Author: "Mathieu Salanne" / Topic: molecular dynamics - Searchworks@Jio Institute Digital Library Search Results

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1. Unexpectedly High Capacitance of the Metal Nanoparticle/Water Interface: Molecular-Level Insights into the Electrical Double Layer

Author: Mahnaz Azimzadeh Sani, Paolo Cignoni, Marie-Pierre Gaigeot, Mathieu Salanne, Julia Linnemann, Kristina Tschulik, Nicholas G. Pavlopoulos, Simone Pezzotti, Alessandra Serva, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Laboratoire Analyse, Modélisation et Matériaux pour la Biologie et l'Environnement (LAMBE - UMR 8587), and Université d'Évry-Val-d'Essonne (UEVE)-Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
Subjects: Materials science, chemistry.chemical_element, Nanoparticle, Nanotechnology, 02 engineering and technology, Electrochemistry, 010402 general chemistry, Capacitance, 7. Clean energy, 01 natural sciences, Catalysis, Corrosion, Metal, Molecular dynamics, Adsorption, ComputingMilieux_MISCELLANEOUS, General Chemistry, General Medicine, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, visual_art, visual_art.visual_art_medium, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Platinum, 0210 nano-technology
Abstract: The electrical double-layer plays a key role in important interfacial electrochemical processes from catalysis to energy stor-age and corrosion. Therefore, understanding its structure is crucial for the progress of sustainable technologies. We extract new physico-chemical information on the capacitance and structure of the electrical double-layer of platinum and gold nanoparticles at the molecular level, employing single nanoparticle electrochemistry. We reveal that the charge storage ability of the solid/liquid interface is larger by one order-of-magnitude than predicted by the traditional mean-field models of the double-layer such as the Gouy-Chapman-Stern-model. Performing Molecular Dynamics simulations, we investigate the possible relationship between the measured high capacitance and adsorption strength of the water adlayer formed at the metal surface. These insights may launch the active tuning of solid-solvent and solvent-solvent interactions as innovative design strategy to transform energy technologies towards superior performance and sustainability.
Published: 2021
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2. Transport Properties of Li-TFSI Water-in-Salt Electrolytes

Author: Benjamin Rotenberg, Anne-Laure Rollet, Olivier Fontaine, Oleg Borodin, Roza Bouchal, Frédéric Favier, Zhujie Li, Cécile Rizzi, Trinidad Méndez-Morales, S. Le Vot, and Mathieu Salanne
Subjects: Aqueous solution, Materials science, 010304 chemical physics, Force field (physics), Ionic bonding, chemistry.chemical_element, Electrolyte, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Ion, Molecular dynamics, chemistry.chemical_compound, chemistry, Chemical physics, 0103 physical sciences, Ionic liquid, Materials Chemistry, Lithium, Physical and Theoretical Chemistry
Abstract: Water-in-salts are a new family of electrolytes that may allow the development of aqueous Li-ion batteries. They have a structure that is reminiscent of ionic liquids, and they are characterized by a high concentration of ionic species. In this work, we study their transport properties and how they evolve with concentration by using molecular dynamic simulations. We first focus on the choice of the force field. By comparing the simulated viscosities and self-diffusion coefficients with experimental measurements, we select a set of parameters that reproduces well the transport properties. We then use the selected force field to study in detail the variations of the self and collective diffusivities of all the species as well as the transport number of the lithium ion. We show that correlations between ions and water play an important role over the whole concentration range. In the water-in-salt regime, the anions form a percolating network that reduces the cation-anion correlations and leads to rather large values for the transport number compared to other standard electrolytes.
Published: 2019
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3. Molecular Dynamics Simulations of Ether-Modified Phosphonium Ionic Liquid Confined in between Planar and Porous Graphene Electrode Models

Author: Guilherme Ferreira Lemos Pereira, Leonardo J. A. Siqueira, Rafael Guimarães Pereira, and Mathieu Salanne
Subjects: chemistry.chemical_classification, Materials science, Ether, 02 engineering and technology, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Molecular dynamics, General Energy, chemistry, Chemical engineering, Ionic liquid, Electrode, Phosphonium, Physical and Theoretical Chemistry, 0210 nano-technology, Alkyl
Abstract: Phosphonium-based ionic liquids with short alkyl chains present low viscosity besides their relative high electrochemical stability. These properties make them good candidates for electrolytes of e...
Published: 2019
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4. Solvation of anthraquinone and Tempo redox-active species in acetonitrile using a polarizable force field

Author: Alessandra Serva, Mathieu Salanne, Kyle G. Reeves, Esther Heid, Roxanne Berthin, and Christian Schroeder
Subjects: chemistry.chemical_compound, Molecular dynamics, Chemical physics, Polarizability, Chemistry, Force field (physics), Ionic liquid, Solvation, Molecule, Density functional theory, Acetonitrile, 3. Good health
Abstract: Redox active molecules are of interest in many fields such as medicine, catalysis or energy storage. In particular, in supercapacitor applications, they can be grafted to ionic liquids to form so-called biredox ionic liquids. To completely understand the structural and transport properties of such systems, an insight at the molecular scale is often required but few force fields are developed ad hoc for these molecules. Moreover, they do not include polarization effects, which can lead to inaccurate solvation and dynamical properties. In this work, we developed polarizable force fields for redox-active species anthraquinone (AQ) and 2,2,6,6-tetra-methylpiperidinyl-1-oxyl (TEMPO) in their oxidized and reduced states, as well as for acetonitrile. We validate structural properties of AQ, AQ$^{\bullet-}$, AQ$^{2-}$, TEMPO$^{\bullet}$ and TEMPO$^{+}$ in acetonitrile against density functional theory-based molecular dynamics simulations and we study the solvation of these redox molecules in acetonitrile. This work is a first step toward the characterization of the role played by AQ and TEMPO in electrochemical and catalytic devices.
Published: 2021
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5. Computational Amperometry of Nanoscale Capacitors in Molecular Simulations

Author: Mathieu Salanne, Thomas Dufils, and Michiel Sprik
Subjects: Condensed Matter - Materials Science, Materials science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Mechanics, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Capacitance, Amperometry, 0104 chemical sciences, law.invention, Capacitor, Molecular dynamics, law, Electrode, General Materials Science, Physical and Theoretical Chemistry, 0210 nano-technology, Constant (mathematics), Electric displacement field, Intensity (heat transfer)
Abstract: In recent years, constant applied potential molecular dynamics has allowed to study the structure and dynamics of the electrochemical double-layer of a large variety of nanoscale capacitors. Nevertheless it remained impossible to simulate polarized electrodes at fixed total charge. Here we show that combining a constant potential electrode with a finite electric displacement fills this gap by allowing to simulate open circuit conditions. The method can be extended by applying an electric displacement ramp to perform computational amperometry experiments at different current intensities. As in experiments, the full capacitance of the system is obtained at low intensity, but this quantity decreases when the applied ramp becomes too fast with respect to the microscopic dynamics of the liquid., Comment: 17 pages, 7 figures
Published: 2021
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6. MetalWalls: A classical molecular dynamics software dedicated to the simulation of electrochemical systems

Author: Sara Bonella, Alessandra Serva, Stewart K. Reed, Alessandro Coretti, Benjamin Rotenberg, Abel Marin-Laflèche, Paul A. Madden, Matthieu Haefele, Thomas Dufils, Guillaume Jeanmairet, Laura Scalfi, Camille Bacon, Roxanne Berthin, Mathieu Salanne, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Mathematical Sciences [Torino] (DISMA), Politecnico di Torino = Polytechnic of Turin (Polito), Centre Européen de Calcul Atomique et Moléculaire (CECAM), École normale supérieure de Lyon (ENS de Lyon)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), School of Chemistry [Leeds], University of Leeds, Department of Materials, University of Oxford, École normale supérieure - Lyon (ENS Lyon)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and University of Oxford [Oxford]
Subjects: Supercapacitor, [PHYS]Physics [physics], Electrode material, 010304 chemical physics, 010405 organic chemistry, business.industry, Computer science, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, Engineering physics, 7. Clean energy, 6. Clean water, 0104 chemical sciences, Molecular dynamics, Software, 0103 physical sciences, Fuel cells, 0210 nano-technology, business, Water desalination
Abstract: International audience; Applied electrochemistry plays a key role in many technologies, such as Li-ion batteries, fuelcells, supercapacitors, solar cells, etc. It is therefore at the core of many research programs allover the world. However, fundamental electrochemical investigations remain scarce. In par-ticular, electrochemistry is among the fields for which the gap between theory and experimentis the largest. From the computational point of view, there is no classical molecular dynamics(MD) software devoted to the simulation of electrochemical systems while other fields such asbiochemistry or material science have dedicated tools.MetalWalls, a MD code dedicated toelectrochemistry, fills this gap. Its main originality is the inclusion of a series of methods whichallow a constant electrical potential to be applied to the electrode materials. It also allowsthe simulation of bulk liquids or solids using the polarizable ion model and the aspherical ionmodel.MetalWallsis designed to be used on high-performance computers and it has alreadybeen employed in a number of scientific publications. It was for example used to study thecharging mechanism of supercapacitors (Merlet et al.,2012), nanoelectrowetting (Choudhuriet al.,2016) and water desalination devices (Simoncelli et al.,2018).
Published: 2020
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7. Solvent-Solvent Correlations across Graphene: The Effect of Image Charges

Author: Mathieu Salanne, Neda Ojaghlou, Mahdi Shafiei, Alenka Luzar, and Dusan Bratko
Subjects: Materials science, Graphene, General Engineering, General Physics and Astronomy, 02 engineering and technology, Substrate (electronics), Conductivity, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, law.invention, Contact angle, chemistry.chemical_compound, Molecular dynamics, chemistry, Chemical physics, law, General Materials Science, Diiodomethane, Wetting, 0210 nano-technology, Polarization (electrochemistry)
Abstract: Wetting experiments show pure graphene to be weakly hydrophilic, but its contact angle (CA) also reflects the character of the supporting material. Measurements and molecular dynamics simulations on suspended and supported graphene often reveal a CA reduction due to the presence of the supporting substrate. A similar reduction is consistently observed when graphene is wetted from both sides. The effect has been attributed to transparency to molecular interactions across the graphene sheet; however, the possibility of substrate-induced graphene polarization has also been considered. Computer simulations of CA on graphene have so far been determined by ignoring the material's conducting properties. We improve the graphene model by incorporating its conductivity according to the constant applied potential molecular dynamics. Using this method, we compare the wettabilities of suspended graphene and graphene supported by water by measuring the CA of cylindrical water drops on the sheets. The inclusion of graphene conductivity and concomitant polarization effects leads to a lower CA on suspended graphene, but the CA reduction is significantly bigger when the sheets are also wetted from the opposite side. The stronger adhesion is accompanied by a profound change in the correlations among water molecules across the sheet. While partial charges on water molecules interacting across an insulator sheet attract charges of the opposite sign, apparent attraction among like charges is manifested across the conducting graphene. The change is associated with graphene polarization, as the image charges inside the conductor attract equally signed partial charges of water molecules on both sides of the sheet. Additionally, using a nonpolar liquid (diiodomethane), we affirm a detectable wetting translucency when liquid-liquid forces are dominated by dispersive interactions. Our findings are important for predictive modeling toward a variety of applications including sensors, fuel cell membranes, water filtration, and graphene-based electrode materials in high-performance supercapacitors.
Published: 2020

8. Size-dependence of hydrophobic hydration at electrified gold/water interfaces

Author: Martina Havenith, Simone Pezzotti, Alessandra Serva, and Mathieu Salanne
Subjects: Work (thermodynamics), Materials science, FOS: Physical sciences, 02 engineering and technology, 010402 general chemistry, Electrochemistry, 01 natural sciences, 7. Clean energy, Metal, Molecular dynamics, Adsorption, Physics - Chemical Physics, Chemical Physics (physics.chem-ph), Condensed Matter - Materials Science, Quantitative Biology::Biomolecules, Multidisciplinary, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, 0104 chemical sciences, Hydrophobe, Volume (thermodynamics), 13. Climate action, Chemical physics, visual_art, Physical Sciences, visual_art.visual_art_medium, 0210 nano-technology, Hydrate
Abstract: Significance The optimization of “green” electrochemical processes is one of the most important challenges in the transition toward renewable energy technologies. In many of these processes, including, e.g., C O 2 and N 2 reduction, small hydrophobic molecules are formed and react at the interface, and their hydration free energy modulates the associated thermodynamics. Here, we use molecular dynamics simulations to elucidate the mechanisms and energetics of hydrophobic hydration at an electrified gold/water interface. We propose an adaptation of the Lum–Chandler–Weeks theory that maps the changes in hydration free energies at the interface as a function of solute size and applied potential.
Published: 2020
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9. Mass-zero constrained molecular dynamics for electrode charges in simulations of electrochemical systems

Author: Giovanni Ciccotti, Laura Scalfi, Alessandro Coretti, Camille Bacon, Benjamin Rotenberg, Mathieu Salanne, Rodolphe Vuilleumier, Sara Bonella, Centre Européen de Calcul Atomique et Moléculaire (CECAM), École normale supérieure de Lyon (ENS de Lyon)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Politecnico di Torino = Polytechnic of Turin (Polito), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare [Sezione di Roma 1] (INFN), Istituto Nazionale di Fisica Nucleare, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE09-0046,NEPTUNE,Transport hors equilibre de fluides aux échelles nanométriques(2017), École normale supérieure - Lyon (ENS Lyon)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: water, Degrees of freedom (statistics), General Physics and Astronomy, FOS: Physical sciences, Kinematics, 010402 general chemistry, 01 natural sciences, Stability (probability), law.invention, Molecular dynamics, law, Physics - Chemical Physics, 0103 physical sciences, [CHIM]Chemical Sciences, Statistical physics, Physical and Theoretical Chemistry, energy-levels, Condensed Matter - Statistical Mechanics, Physics, [PHYS]Physics [physics], Chemical Physics (physics.chem-ph), 010304 chemical physics, Statistical Mechanics (cond-mat.stat-mech), Charge density, Computational Physics (physics.comp-ph), 0104 chemical sciences, Capacitor, Electrode, Constant (mathematics), Physics - Computational Physics
Abstract: International audience; Classical molecular dynamics simulations have recently become a standard tool for the study of electrochemical systems. State-of-the-art approaches represent the electrodes as perfect conductors, modelling their responses to the charge distribution of electrolytes via the so-called fluctuating charge model. These fluctuating charges are additional degrees of freedom that, in a Born-Oppenheimer spirit, adapt instantaneously to changes in the environment to keep each electrode at a constant potential. Here we show that this model can be treated in the framework of constrained molecular dynamics, leading to a symplectic and time-reversible algorithm for the evolution of all the degrees of freedom of the system. The computational cost and the accuracy of the new method are similar to current alternative implementations of the model. The advantage lies in the accuracy and long term stability guaranteed by the formal properties of the algorithm and in the possibility to systematically introduce additional kinematic conditions of arbitrary number and form. We illustrate the performance of the constrained dynamics approach by enforcing the electroneutrality of the electrodes in a simple capacitor consisting of two graphite electrodes separated by a slab of liquid water.
Published: 2020
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10. Structural study of Na2O-B2O3-SiO2-La2O3 glasses from molecular simulations using a polarizable force field

Author: Fabien Pacaud, Jean-Marc Delaye, Thibault Charpentier, Laurent Cormier, Mathieu Salanne, Service Manutention Phénix (SMP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA Marcoule, Bagnols-sur-Ceze, France, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Propriétés des amorphes, liquides et minéraux [IMPMC] (IMPMC_PALM), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), and Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Lanthanide, Materials science, Ionic bonding, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Electronic structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Force field (chemistry), 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Ion, Molecular dynamics, Homogeneous, Polarizability, Chemical physics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Chemistry, Ceramics and Composites, [PHYS.COND.CM-DS-NN]Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn], 0210 nano-technology
Abstract: International audience; The properties of Na2O-B2O3-SiO2+La2O3 glasses (NBS_La) are not well understood. In particular the influence of the lanthanides on the polymerized network structure and organization are not well known. In this work, we use a Polarizable Ion Model (PIM) that was fitted on electronic structure calculations to simulate a series of NBS_La glasses using molecular dynamics. The simulations account well for the main structural characteristics of NBS_La glasses such as the structure factors and the ionic local environments despite minor discrepancies with experiments about the Si-O distance and the B coordination. In particular, we examine the impact of La2O3 addition to Na2O-B2O3-SiO2 glasses in term of structural changes and in the Na migration paths which become more homogeneous.
Published: 2018
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11. Structure and dynamics of aqueous NaCl solutions at high temperatures and pressures

Author: Annalisa Polidori, Mathieu Salanne, Anita Zeidler, Burkhard Annighöfer, Stefan Klotz, Ruth F. Rowlands, Henry E. Fischer, and Philip S. Salmon
Subjects: Materials science, Aqueous solution, Hydrogen bond, Coordination number, Neutron diffraction, Isotopes of chlorine, General Physics and Astronomy, Physics and Astronomy(all), Chloride, Ion, Molecular dynamics, Chemical physics, medicine, Physical and Theoretical Chemistry, medicine.drug
Abstract: The structure of a concentrated solution of NaCl in D2O was investigated by in situ high-pressure neutron diffraction with chlorine isotope substitution to give site-specific information on the coordination environment of the chloride ion. A broad range of densities was explored by first increasing the temperature from 323 to 423 K at 0.1 kbar and then increasing the pressure from 0.1 to 33.8 kbar at 423 K, thus mapping a cyclic variation in the static dielectric constant of the pure solvent. The experimental work was complemented by molecular dynamics simulations using the TIP4P/2005 model for water, which were validated against the measured equation of state and diffraction results. Pressure-induced anion ordering is observed, which is accompanied by a dramatic increase in the Cl–O and O–O coordination numbers. With the aid of bond-distance resolved bond-angle maps, it is found that the increased coordination numbers do not originate from a sizable alteration to the number of either Cl⋯D–O or O⋯D–O hydrogen bonds but from the appearance of non-hydrogen-bonded configurations. Increased pressure leads to a marked decrease in the self-diffusion coefficients but has only a moderate effect on the ion–water residence times. Contact ion pairs are observed under all conditions, mostly in the form of charge-neutral NaCl0 units, and coexist with solvent-separated Na+–Na+ and Cl−–Cl− ion pairs. The exchange of water molecules with Na+ adopts a concerted mechanism under ambient conditions but becomes non-concerted as the state conditions are changed. Our findings are important for understanding the role of extreme conditions in geochemical processes.
Published: 2021
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12. Ca 2+ ‐Cl − Association in Water Revisited: the Role of Cation Hydration

Author: Mathieu Salanne, Benjamin Rotenberg, Sami Tazi, Rodolphe Vuilleumier, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Subjects: Coordination sphere, 010304 chemical physics, Chemistry, Coordination number, Ionic bonding, 010402 general chemistry, 01 natural sciences, Atomic and Molecular Physics, and Optics, Dissociation (chemistry), 0104 chemical sciences, Molecular dynamics, Chemical physics, Computational chemistry, Ab initio quantum chemistry methods, 0103 physical sciences, Physics::Atomic and Molecular Clusters, [CHIM]Chemical Sciences, Molecule, Physics::Chemical Physics, Physical and Theoretical Chemistry, Potential of mean force
Abstract: International audience; We investigate the dissociation of a Ca2+-Cl− pair in water using classical molecular dynamics simulations with a polarizable interaction potential, parameterized from ab initio calculations. By computing the potential of mean force as a function not only of the interionic distance but also of the coordination numbers by water molecules, we show that it is necessary to use a collective variable describing the cation hydration in order to capture the dissociation mechanism. In the contact ion pair, the Ca2+ cation has a first coordination sphere containing 5 or 6 water molecules. The minimum free-energy path for dissociation involves a two-step process: First one or two additional water molecules enter the cation coordination shell, increasing the coordination number up to 7 with an almost fixed interionic distance. Then the dissociation of the ionic pair occurs at this fixed coordination number.
Published: 2017
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13. Study of a water-graphene capacitor with molecular density functional theory

Author: Benjamin Rotenberg, Daniel Borgis, Mathieu Salanne, Guillaume Jeanmairet, Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Subjects: Chemical Physics (physics.chem-ph), Materials science, 010304 chemical physics, Molecular model, Graphene, General Physics and Astronomy, FOS: Physical sciences, 010402 general chemistry, 01 natural sciences, Capacitance, 0104 chemical sciences, law.invention, Capacitor, Molecular dynamics, law, Chemical physics, Physics - Chemical Physics, 0103 physical sciences, Electrode, Molecular Density, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS, Voltage
Abstract: Most of the performances of electrochemical devices are governed by molecular processes taking place at the solution-electrode interfaces and molecular simulation are the main way to study these processes. Aqueous electrochemical systems have often been studied using classical DFT but with too crude approximations to consider the system description to be realistic. We study the interface between graphene electrodes and liquid water at different applied voltage using molecular DFT, improving the state of the art by the following key points: 1) electrodes have a realistic atomic resolution, 2) classical DFT calculations are carried out at fixed imposed potential difference and 3) water is described by a molecular model. This allows to reveal the structural modification of water adsorbed at the graphene interface and the evolution of water dielectric permittivity when a voltage is applied. The computed capacitance of this device is in agreement with molecular dynamics simulations. This demonstrates the relevance of molecular DFT to study electrochemical systems at the molecular level., 6 pages, 5 figures, Supplementary infos
Published: 2019
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14. NMR shifts in aluminosilicate glasses via machine learning

Author: Jean-Marc Delaye, Mathieu Salanne, Ziyad Chaker, Thibault Charpentier, Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Matériaux et Procédés Actifs (LMPA), Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D)
Subjects: Materials science, business.industry, Computation, Isotropy, Ab initio, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Machine learning, computer.software_genre, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Molecular dynamics, Dimension (vector space), Aluminosilicate, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Artificial intelligence, Physical and Theoretical Chemistry, 0210 nano-technology, Focus (optics), business, computer
Abstract: International audience; Machine learning (ML) approaches are investigated for the prediction of nuclear magnetic resonance (NMR) parameters in aluminosilicate glasses, for which NMR has proven to be a cutting-edge method over the last decade. DFT computations have emerged as a new dimension for complementing these NMR methods although suffering from severe limitations in terms of size, time and computational resources consumption. While previous approaches tend to use DFT-GIPAW calculations for the prediction of NMR parameters in glassy systems, we propose to employ ML methods, characterized by a speed similar to that of classical molecular dynamics while the accuracy of ab initio methods can be reached. We design ML procedures to predict the isotropic magnetic shielding (σiso) for different multicomponent relevant glass compositions. The ML predictions of σiso deviate from DFT-GIPAW calculations, when including relaxed and room-temperature structures, by 0.7 ppm for 29Si (1.0% of the total span of the calculated ) and 1.5 ppm for 17O (1.9%) in SiO2 glasses, 1.4 ppm for 23Na (1.5%) in Na2O–SiO2 and 1.5 ppm for 27Al (2.1%) in Al2O3–Na2O–SiO2 systems. We compare the performances obtained for a set of three descriptors suitable for encoding atomic local environments information (atom-centered representations) together with seven popular ML algorithms with a focus on the simple (but robust) linear ridge regression (LRR) and the popular smooth overlap of atomic positions (SOAP) descriptor.
Published: 2019
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15. Simulating Electrochemical Systems by Combining the Finite Field Method with a Constant Potential Electrode

Author: Benjamin Rotenberg, Michiel Sprik, Mathieu Salanne, Thomas Dufils, Guillaume Jeanmairet, Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and University of Cambridge [UK] (CAM)
Subjects: Condensed Matter - Materials Science, Materials science, Statistical Mechanics (cond-mat.stat-mech), General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Electrolyte, Electrochemistry, 01 natural sciences, Molecular dynamics, Dipole, Chemical physics, Electric field, 0103 physical sciences, Electrode, [CHIM]Chemical Sciences, Surface charge, Physics::Chemical Physics, 010306 general physics, Polarization (electrochemistry), Condensed Matter - Statistical Mechanics
Abstract: A better understanding of interfacial mechanisms is needed to improve the performances of electrochemical devices. Yet, simulating an electrode surface at fixed electrolyte composition remains a challenge. Here we apply a finite electric field to a single electrode held at constant potential and in contact with an aqueous ionic solution, using classical molecular dynamics. The polarization yields two electrochemical interfaces on opposite sides of the same metal slab. While the net charge on one electrode surface is the opposite of the net charge on the other, maintaining overall charge neutrality of the metal. The electrode surface charges fluctuations are compensated by the adsorption of ions from the electrolyte, forming a pair of electric double layers with aligned dipoles. This opens the way towards the efficient simulation of electrochemical interfaces using any flavor of molecular dynamics, from classical to first principles-based methods., Comment: 6 pages, 7 figures (including SI)
Published: 2019
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16. Study of the Partial Charge Transport Properties in the Molten Alumina via Molecular Dynamics

Author: Catherine Bessada, Alessandra Serva, Patrice Chartrand, Kelly Machado, Didier Zanghi, Mathieu Salanne, Aïmen E. Gheribi, École Polytechnique de Montréal (EPM), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), and Université d'Orléans (UO)
Subjects: Materials science, General Chemical Engineering, 02 engineering and technology, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, Article, 0104 chemical sciences, lcsh:Chemistry, Molecular dynamics, Partial charge, lcsh:QD1-999, Chemical physics, 0210 nano-technology, Energy (signal processing), ComputingMilieux_MISCELLANEOUS
Abstract: Knowing the charge-transport properties of molten oxides is essential for industrial applications, particularly when attempting to control the energy required to separate a metal from its ore concentrate. Nowadays, in the context of a drastic increase of computational resources, research in industrial process simulation and their optimization is gaining popularity. Such simulations require accurate data as input for properties in a wide range of compositions, temperatures, and mechanical stresses. Unfortunately, due to their high melting points, we observe a severe lack of (reproducible) experimental data for many of the molten oxides. An alternative consists in using molecular dynamic simulations employing nonempirical force fields to predict the charge-transport properties of molten oxides and thus alleviate the lack of experimental data. Here, we study molten alumina using two polarizable force fields, with different levels of sophistication, parameterized on electronic structure calculations only. After validating the models against the experimental sets of density and electrical conductivity, we are able to determine the various ionic contributions to the overall charge transport in a wide range of temperatures.
Published: 2019
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17. Chasing Aqueous Biphasic Systems from simple salts by exploring the LiTFSI/LiCl/H2O phase diagram

Author: Annie Colin, Alexis Grimaud, Matej Kanduč, Benjamin Rotenberg, Mathieu Salanne, Chanbum Park, Michaël Deschamps, Soufiane Abdelghani-Idrissi, Joachim Dzubiella, and Nicolas Dubouis
Subjects: chemistry.chemical_classification, Aqueous solution, Materials science, chemistry.chemical_element, Polymer, Ion, Molecular dynamics, chemistry.chemical_compound, Chemical engineering, chemistry, Ionic liquid, Lithium, Imide, Phase diagram
Abstract: Aqueous Biphasic Systems (ABS), in which two aqueous phases with different compositions coexist as separate liquids, have first been reported over a century ago with polymer solutions. Recent observations of ABS forming from concentrated mixtures of inorganic salts and ionic liquids raise the fundamental question of how "different" the components of such mixtures should be for a liquid-liquid phase separation to occur. Here we show that even two monovalent salts sharing a common cation (lithium) but with different anions, namely LiCl and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), may result in the formation of ABSs over a wide range of compositions at room temperature. Using a combination of experimental techniques and molecular simulations, we analyze the coexistence diagram and the mechanism driving the phase separation, arising from the different anion sizes. The understanding and control of ABS may provide new avenues for aqueous-based battery systems.
Published: 2019
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18. Structural, Dynamic, and Thermodynamic Study of KF–AlF 3 Melts by Combining High-Temperature NMR and Molecular Dynamics Simulations

Author: Catherine Bessada, Didier Zanghi, Mathieu Salanne, Kelly Machado, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), Université d'Orléans (UO), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), and Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, chemistry.chemical_element, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, Cryolite, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Solvent, chemistry.chemical_compound, Molecular dynamics, General Energy, Chemical engineering, chemistry, Aluminium, Physical and Theoretical Chemistry, 0210 nano-technology, Fluoride
Abstract: International audience; Molten cryolite (NaF-AlF 3) plays a key role for aluminum production since it is used as a solvent. Among the various leads to improve the electrochemical processes, adding other fluoride salts is one of the most promising. However there is very few data on the impact of these additional species on the physico-chemical properties of the melt. In order to fill this gap we investigate the properties of high temperature KF-AlF 3 liquids by combining NMR spectroscopy, molecular dynamics and DFT calculations. Our results show that the speciation, and consequently the transport properties differ from that of cryolite. This work will allow to assess the interest of adding KF in aluminium production processes.
Published: 2019
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19. Formulation of Temperature-Dependent Thermal Conductivity of NaF, β-Na3AlF6, Na5Al3F14, and Molten Na3AlF6 Supported by Equilibrium Molecular Dynamics and Density Functional Theory

Author: Patrice Chartrand, Aïmen E. Gheribi, and Mathieu Salanne
Subjects: Work (thermodynamics), Series (mathematics), Ionic bonding, Thermodynamics, 02 engineering and technology, Function (mathematics), 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Cryolite, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Molecular dynamics, General Energy, Thermal conductivity, chemistry, Density functional theory, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: Numerical modeling of heat transport in the side ledge of a cryolite bath as a function of its thickness requires an accurate knowledge of the thermal transport properties of the cryolite bath as well as the solid phases constituting the side ledge. Unfortunately, due to experimental limitations, there is a lack of experimental data on this subject. The aim of this work is to predict these otherwise unknown properties. The thermal conductivity of major constituents of the side ledge in their solid state, namely: NaF, β– Na3AlF6 and Na5Al3F14 as well as molten Na3AlF6 are formulated as a function of temperature. To achieve this, we have performed a series of equilibrium molecular dynamics simulations (EMD) in both the NPT (isobar-isotherm) and NVT (canonical) statistical ensembles. The proposed approach is purely predictive as the ionic interaction potentials were parametrized on the basis of Density Functional Theory (DFT). The results are then compared to a theoretical model which has been shown to be a ...
Published: 2016
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20. Dynamic Response in Nanoelectrowetting on a Dielectric

Author: Jyoti Roy Choudhuri, Paul A. Madden, Dusan Bratko, Mathieu Salanne, Alenka Luzar, and Davide Vanzo
Subjects: Materials science, Drop (liquid), General Engineering, Analytical chemistry, General Physics and Astronomy, Response time, 02 engineering and technology, Dielectric, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Contact angle, Molecular dynamics, Chemical physics, Electrode, Miniaturization, General Materials Science, 0210 nano-technology, Electrode potential
Abstract: Droplet spreading at an applied voltage underlies the function of tunable optical devices including adjustable lenses and matrix display elements. Faster response and the enhanced resolution motivate research toward miniaturization of these devices to nanoscale dimensions. The response of an aqueous nanodroplet to an applied field can differ significantly from macroscopic predictions. Understanding these differences requires characterization at the molecular level. We describe the equilibrium and nonequilibrium molecular dynamics simulations of nanosized aqueous droplets on a hydrophobic surface with the embedded concentric electrodes. Constant electrode potential is enforced by a rigorous account of the metal polarization. We demonstrate that the reduction of the equilibrium contact angle is commensurate to, and adjusts reversibly with, the voltage change. For a droplet with O(10) nm diameter, a typical response time to the imposition of the field is of O(10(2)) ps. Drop relaxation is about twice as fast when the field is switched off. The friction coefficient obtained from the rate of the drop relaxation on the nonuniform surface, decreases when the droplet approaches equilibrium from either direction, that is, by spreading or receding. The strong dependence of the friction on the surface hydrophilicity points to the dominance of the liquid-surface friction at the drop's perimeter as described in the molecular kinetic theory. This approach enables correct predictions of trends in dynamic responses associated with varied voltage or substrate material.
Published: 2016
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21. Molecular Dynamics Simulations of the Influence of Drop Size and Surface Potential on the Contact Angle of Ionic-Liquid Droplets

Author: Xiu Song Zhao, Ryan Burt, Greg Birkett, and Mathieu Salanne
Subjects: Materials science, Analytical chemistry, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Ion, law.invention, Physics::Fluid Dynamics, Contact angle, chemistry.chemical_compound, Molecular dynamics, law, Metastability, Physical and Theoretical Chemistry, Graphene, Drop (liquid), 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, chemistry, Chemical physics, Ionic liquid, Wetting, 0210 nano-technology
Abstract: In this work we have performed molecular dynamics simulations of the room temperature ionic-liquid 1-ethyl-3-methylimidazolium tetrafluoroborate on a surface with graphene structured sheets. Contact angles were calculated via polynomial-fitting of two-dimensional atomic density contours. Drop size and surface interaction were varied to assess their influences on the contact angle. At low graphene interaction potential, no change in contact angle with drop size was found. When increasing the surface interaction potential toward actual graphene, the drops deviated to fully wetting, but the spreading rate and extent became dependent on drop size. The smallest drop formed a single adsorbed layer due to its initial size and the large ratio of ions in the adsorbed layer. Larger drops wetted and formed nonuniform metastable drops upon several layers of spread liquid. These were not true equilibrium structures as when starting from a single adsorbed layer film at room temperature, the metastable layers were not r...
Published: 2016
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22. Investigation of ionic local structure in molten salt fast reactor LiF-ThF4-UF4 fuel by EXAFS experiments and molecular dynamics simulations

Author: Mathieu Gibilaro, Mathieu Salanne, Pierre Chamelot, Catherine Bessada, Haruaki Matsuura, Atsushi Nezu, Ana Gil-Martin, Laurent Massot, Didier Zanghi, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), Université d'Orléans (UO), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie Chimique (LGC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Research Laboratory for Nuclear Reactors (RLNR), Tokyo Institute of Technology [Tokyo] (TITECH), and Tokyo City University
Subjects: Materials science, Absorption spectroscopy, Population, Analytical chemistry, chemistry.chemical_element, Ionic bonding, 02 engineering and technology, Molecular dynamics, 010402 general chemistry, 01 natural sciences, Ion, high temperature, Materials Chemistry, Physical and Theoretical Chemistry, Molten salt, education, Spectroscopy, Eutectic system, education.field_of_study, actinides, Extended X-ray absorption fine structure, molten salt reactors, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, EXAFS, speciation, chemistry, Fluorine, 0210 nano-technology
Abstract: This article focuses on the speciation of molten fluoride mixtures based on ThF4 and UF4 actinides used in molten salt reactors. The local structure of molten AF-MF4 systems (A = Li+, Na+, K+; M = Th4+, U4+) was studied in situ by combining measurements by high temperature X-ray absorption spectroscopy and molecular dynamics simulations. In the molten state, 20 higher than the melting temperature, these mixtures are composed of free fluorine and anionic species [MF7]3−, [MF8]4− and [MF9]5− whose distribution varies with the amount of MF4 (M = Th4+, U4+). Regardless of the cation, these complexes consist of an average of 8 F− neighbors for MF4 content is lower than 35 mol%. This value decreases to 7 as the size of the alkaline ion A (A = Li+, Na+, K+) increases. The [MFx]4−x species are linked together by bridging fluorine ions to form long chains [MxFY]4x−y. The addition of a few percent UF4 to the eutectic LiF-ThF4 composition (77.5 mol% - 22.5 mol%) at leads to a slight increase in the population of free fluorine ions due to the breakdown of the Th-F links to form complexes [UFx]4−x isolated or connected to the (ThxFy)4x−y chains. This change in the structure of the liquid results in a slight decrease in viscosity when a few mol. % of UF4 is added.
Published: 2020
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23. Chasing Aqueous Biphasic Systems from Simple Salts by Exploring the LiTFSI

Author: Alexis Grimaud, Matej Kanduč, Mathieu Salanne, Benjamin Rotenberg, Annie Colin, Nicolas Dubouis, Michaël Deschamps, Joachim Dzubiella, Soufiane Abdelghani-Idrissi, and Chanbum Park
Subjects: chemistry.chemical_classification, chemistry.chemical_compound, Molecular dynamics, Aqueous solution, chemistry, Chemical engineering, Ionic liquid, chemistry.chemical_element, Lithium, Polymer, Imide, Phase diagram, Ion
Abstract: Aqueous Biphasic Systems (ABS), in which two aqueous phases with different compositions coexist as separate liquids, have first been reported over a century ago with polymer solutions. Recent observations of ABS forming from concentrated mixtures of inorganic salts and ionic liquids raise the fundamental question of how "different" the components of such mixtures should be for a liquid-liquid phase separation to occur. Here we show that even two monovalent salts sharing a common cation (lithium) but with different anions, namely LiCl and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), may result in the formation of ABSs over a wide range of compositions at room temperature. Using a combination of experimental techniques and molecular simulations, we analyze the coexistence diagram and the mechanism driving the phase separation, arising from the different anion sizes. The understanding and control of ABS may provide new avenues for aqueous-based battery systems.
Published: 2018
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24. A First-Principles Computational Comparison of the Aqueous Anatase TiO2 (001) Interface and the Disordered, Fluorinated TiO2 Interface

Author: Damien Dambournet, Christel Laberty-Robert, Mathieu Salanne, Kyle G. Reeves, and Rodolphe Vuilleumier
Subjects: Molecular dynamics, Anatase, Materials science, Adsorption, Chemical physics, Density of states, Molecule, Density functional theory, Fermi energy, Dissociation (chemistry)
Abstract: Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO2 with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and amonolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that thevariation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change inthe density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.
Published: 2018
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25. Anionic Structure in Molten Cryolite–Alumina Systems

Author: Mathieu Salanne, Kelly Machado, Vincent Stabrowski, Catherine Bessada, Didier Zanghi, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), and Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, Electronic structure, Electrolyte, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Cryolite, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Ion, chemistry.chemical_compound, Molecular dynamics, General Energy, chemistry, Aluminium, Physical and Theoretical Chemistry, 0210 nano-technology, Dissolution, ComputingMilieux_MISCELLANEOUS
Abstract: For aluminum production, the alumina (Al2O3) dissolution in the electrolyte is one of the important step in the industrial process. The electrolyte is a cryolitic bath containing mainly NaF and AlF3 at around 1000 °C. In this liquid, the main anionic species are fluoroaluminates ions such as [AlF6]3–, [AlF5]2–, [AlF4]−, and F–. During the Al2O3 dissolution, different kinds of oxyfluoroaluminates species are formed. However, due to the difficult experimental conditions and the large number of potential ions, no quantitative speciation could be made up to now. Here, we propose a speciation of alumina–cryolite melts combining in situ NMR experiments, classical molecular dynamics simulations, and electronic structure calculations. This allows us to establish the nature and quantities of each species, depending on the Al2O3 concentration, for two different initial cryolitic compositions. In particular, we show that the O atoms are always linked to at least two Al atoms, leading to the formation of polymeric ox...
Published: 2018
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26. On the determination of ion transport numbers in molten salts using molecular dynamics

Author: Patrice Chartrand, Aïmen E. Gheribi, Catherine Bessada, Didier Zanghi, Mathieu Salanne, Kelly Machado, École Polytechnique de Montréal (EPM), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), and Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, General Chemical Engineering, Ionic bonding, 02 engineering and technology, Statistical mechanics, Electrolyte, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Ion, Molecular dynamics, Electrical resistivity and conductivity, Chemical physics, Electrochemistry, Ionic conductivity, Molten salt, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: Individual transport numbers provide a measure of the charge ratio which is carried by each ionic species of an electrolyte. However, unlike the electrical conductivity or diffusion coefficients, this quantity lacks a clear definition from the statistical mechanics point of view. In practice, it is measured via complex experimental setups, and most of the interpretation of the available data is made by using the Nernst–Einstein approximation. Here we show that this approach is not suitable in molten salts due to the large contributions of the cross-terms due to the ionic interactions in the total ionic conductivity. We propose a partition scheme that allows to attribute these cross-terms to the various ions, allowing for an estimate of the transport numbers in a series of molten salt formed by mixing NaF and AlF3 at various compositions. The results are interpreted using the speciation of the melt, which is characterized by the formation of various AlFx clusters. At large AlF3, the Na+ ions are shown to contribute almost totally to the ionic conductivity.
Published: 2018
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27. Computer simulation studies of nanoporous carbon-based electrochemical capacitors

Author: Zhujie Li, Trinidad Méndez-Morales, Mathieu Salanne, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), ANR-10-LABX-0076,STORE-EX,Laboratory of excellency for electrochemical energy storage(2010), ANR-17-ERC2-0028,SELFIE,Electrolytes superconcentrés pour les applications électrochimiques(2017), European Project: 676629,H2020 Pilier Excellent Science,H2020-EINFRA-2015-1,EoCoE(2015), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Maison de la Simulation ( MDLS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX ( PHENIX ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -ESPCI ParisTech-Centre National de la Recherche Scientifique ( CNRS ), Réseau sur le stockage électrochimique de l'énergie ( RS2E ), Centre National de la Recherche Scientifique ( CNRS ), ANR-10-LABX-0076/10-LABX-0076,STORE-EX,Laboratory of excellency for electrochemical energy storage ( 2010 ), ANR-17-ERC2-0028,SELFIE,Electrolytes superconcentrés pour les applications électrochimiques, and European Project : 676629,H2020 Pilier Excellent Science,H2020-EINFRA-2015-1,EoCoE ( 2015 )
Subjects: Materials science, Nanoporous, Complex system, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, law.invention, Amorphous solid, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Capacitor, Molecular dynamics, Nanopore, law, [ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistry, Electrode, Electrochemistry, Surface modification, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: Summary Among the various techniques that are used for understanding the operation of electrochemical energy storage devices, computer simulations are now playing a key role. In the case of electrochemical capacitors, the main driving force is the adsorption of ions at the surface of a nanoporous electrode, so that the most widespread simulation technique is molecular dynamics, which gives access to a microscopic picture. Here, we review the most recent advances in the elucidation of charging mechanisms for a wide range of electrode geometries, ranging from slit to amorphous nanopores. We also discuss the impact of surface functionalization, doping and oxidation on the performance of electrochemical devices as predicted using such computer simulation techniques. Finally, we provide a few perspectives on the difficulties that still need to be overcome for fully understanding the complex systems, which are used in electrochemical devices.
Published: 2018
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28. Classical Polarizable Force Field to Study Hydrated Hectorite: Optimization on DFT Calculations and Validation against XRD Data

Author: Benjamin Rotenberg, Eric Ferrage, Vivien Ramothe, Virginie Marry, Stéphane Tesson, Baptiste Dazas, Ragnhild Hånde, Bruno Lanson, Mathieu Salanne, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Diffraction, Materials science, lcsh:QE351-399.2, molecular dynamics, density functional theory, polarizability, X-ray diffraction, hydrated charged clay, Na-, Ca-, Sr- and Cs-hectorites, Thermodynamics, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Force field (chemistry), Physics::Geophysics, Molecular dynamics, Polarizability, lcsh:Mineralogy, Geology, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Geotechnical Engineering and Engineering Geology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Dipole, Na, Hectorite, Density functional theory, 0210 nano-technology, Electronic density
Abstract: International audience; Following our previous works on dioctahedral clays, we extend the classical Polarizable Ion Model (PIM) to trioctahedral clays, by considering dry Na-, Cs-, Ca-and Sr-hectorites as well as hydrated Na-hectorite. The parameters of the force field are determined by optimizing the atomic forces and dipoles on density functional theory calculations. The simulation results are validated by comparison with experimental X-ray diffraction (XRD) data. The XRD patterns calculated from classical molecular dynamics simulations performed with the PIM force field are in very good agreement with experimental results. In the bihydrated state, the less structured electronic density profile obtained with PIM compared to the one from the state-of-the-art non-polarizable force field clayFF explains the slightly better agreement between the PIM results and experiments.
Published: 2018
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29. In situ high-temperature EXAFS measurements on radioactive and air-sensitive molten salt materials

Author: E. Capelli, Jörg Rothe, Philippe Martin, Malte N. Verleg, Aïmen E. Gheribi, Anna Smith, Rudy J. M. Konings, Dick de Haas, Kathy Dardenne, Jaen A. Ocadiz-Flores, Mathieu Salanne, Lambert van Eijck, J. Vlieland, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), and Université Paris sciences et lettres (PSL)
Subjects: Technology, Nuclear and High Energy Physics, Materials science, XAFS, Neutron diffraction, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, chemistry.chemical_compound, Thorium tetrafluoride, neutron diffraction, law, [CHIM]Chemical Sciences, Molten salt, Instrumentation, fluoride salts, Radiation, Extended X-ray absorption fine structure, Molten salt reactor, Thorium, 021001 nanoscience & nanotechnology, Research Papers, molecular dynamics, 0104 chemical sciences, X-ray absorption fine structure, Beamline, chemistry, molten salt reactor, 0210 nano-technology, ddc:600
Abstract: An experimental set-up and specific sample containment allowing high-temperature in situ EXAFS measurements of radioactive, air-sensitive and corrosive fluoride salts is described. First results are reported and compared with molecular dynamics simulations of the highly disordered liquid salts., The development at the Delft University of Technology (TU Delft, The Netherlands) of an experimental set-up dedicated to high-temperature in situ EXAFS measurements of radioactive, air-sensitive and corrosive fluoride salts is reported. A detailed description of the sample containment cell, of the furnace design, and of the measurement geometry allowing simultaneous transmission and fluorescence measurements is given herein. The performance of the equipment is tested with the room-temperature measurement of thorium tetrafluoride, and the Th—F and Th—Th bond distances obtained by fitting of the EXAFS data are compared with the ones extracted from a refinement of neutron diffraction data collected at the PEARL beamline at TU Delft. The adequacy of the sample confinement is checked with a mapping of the thorium concentration profile of molten salt material. Finally, a few selected salt mixtures (LiF:ThF4) = (0.9:0.1), (0.75:0.25), (0.5:0.5) and (NaF:ThF4) = (0.67:0.33), (0.5:0.5) are measured in the molten state. Qualitative trends along the series are discussed, and the experimental data for the (LiF:ThF4) = (0.5:0.5) composition are compared with the EXAFS spectrum generated from molecular dynamics simulations.
Published: 2018
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30. A Molecular Density Functional Theory Approach to Electron Transfer Reactions

Author: Daniel Borgis, Maximilien Levesque, Mathieu Salanne, Guillaume Jeanmairet, Benjamin Rotenberg, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ANR-15-CE09-0013,LENNS,Ecouter le bruit électrique pour les capteurs nanofluidiques(2015), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris)
Subjects: Physics, Chemical Physics (physics.chem-ph), 010405 organic chemistry, Band gap, Thermodynamics, FOS: Physical sciences, Observable, General Chemistry, Dielectric, 010402 general chemistry, 01 natural sciences, Force field (chemistry), 0104 chemical sciences, 3. Good health, Marcus theory, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Electron transfer, Molecular dynamics, Chemistry, Physics - Chemical Physics, Molecular Density
Abstract: Beyond the dielectric continuum description initiated by Marcus theory, the nowadays standard theoretical approach to study electron transfer (ET) reactions in solution or at interfaces is to use classical force field or ab initio Molecular Dynamics simulations. We propose here an alternative method based on liquid-state theory, namely molecular density functional theory, which is numerically much more efficient than simulations while still retaining the molecular nature of the solvent. We begin by reformulating molecular ET theory in a density functional language and show how to compute the various observables characterizing ET reactions from an ensemble of density functional minimizations. In particular, we define in that formulation the relevant order parameter of the reaction, the so-called vertical energy gap, and determine the Marcus free energy curves of both reactant and product states along that coordinate. Important thermodynamic quantities such as the reaction free energy and the reorganization free energies follow. We assess the validity of the method by studying the model Cl$^0\rightarrow$ Cl$^+$ and Cl$^0\rightarrow$ Cl$^-$ ET reactions in bulk water for which molecular dynamics results are available. The anionic case is found to violate the standard Marcus theory. Finally, we take advantage of the computational efficiency of the method to study the influence of confinement on the ET, by investigating the evolution of the reorganization free energy of the Cl$^0\rightarrow$ Cl$^+$ reaction when the atom approaches an atomistically resolved wall., Comment: 30 pages, 10 figures, Chemical Science, 2019
Published: 2018
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31. Toward an Accurate Modeling of Ionic Liquid–TiO2 Interfaces

Author: Barbara Kirchner, Mathieu Salanne, and Henry Weber
Subjects: Anatase, Chemistry, Ab initio, Analytical chemistry, Electrolyte, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Condensed Matter::Soft Condensed Matter, chemistry.chemical_compound, Molecular dynamics, General Energy, Adsorption, Chemical physics, Ionic liquid, Surface layer, Physical and Theoretical Chemistry, Polarization (electrochemistry)
Abstract: Structural properties of the ionic liquids 1-ethyl-3-methylimidazolium thiocyanate and tetracyanoborate at the anatase (101) surface are of crucial interest for energy harvesting and storage devices, but their investigation via molecular dynamics requires large simulation cells. Thus, two classical interaction potentials with and without polarization effects were parametrized in order to accurately model the interface between the liquid and solid. The parameters were fitted to match ab initio reference interaction energies. Application of the generated force field to model the interface is demonstrated. The adsorption profiles of the ionic liquid’s components reveal a very dense surface layer with an excess of cations, which has some possible implications for the use of the ionic liquids as electrolytes, for example in solar cells.
Published: 2015
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32. Molecular aspects of the Eu3+/Eu2+ redox reaction at the interface between a molten salt and a metallic electrode

Author: Paul A. Madden, Michael A. Pounds, and Mathieu Salanne
Subjects: Chemistry, Inorganic chemistry, Biophysics, Electrolyte, Condensed Matter Physics, Electrochemistry, Marcus theory, Ion, Molecular dynamics, Electron transfer, Chemical physics, Electric potential, Physical and Theoretical Chemistry, Molten salt, Molecular Biology
Abstract: We perform molecular dynamics simulations of a system consisting of Eu3+ and Eu2+ species dissolved in a high-temperature KCl electrolyte between two metallic electrodes. The interaction potential includes ion polarisation effects, and a constant electric potential is maintained within the electrodes by allowing the atomic charges to fluctuate in response to the environment. This setup allows us to study the electrochemical Eu3+/Eu2+ reaction in the framework of Marcus theory. Numerous studies have pointed to the highly structured nature of ionic liquids and molten salts close to solid surfaces which is not accounted for in the conventional mean-field description of this interface that underpins the theories of electrochemical reaction rates. Here we examine the influence on the kinetics of the charge-transfer event of the electrical potential across the electrode–electrolyte interface and on the effect of the presence of charged surface on the coordination structure and energetics of the ions in the regi...
Published: 2015
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33. Transport coefficients and the Stokes–Einstein relation in molten alkali halides with polarisable ion model

Author: Satoshi Kasai, Norikazu Ohtori, Yoshiki Ishii, and Mathieu Salanne
Subjects: Ionic radius, Chemistry, Inorganic chemistry, Biophysics, Thermodynamics, Slip (materials science), Condensed Matter Physics, Ion, Molecular dynamics, Thermal conductivity, Electrical resistivity and conductivity, Density functional theory, Boundary value problem, Physical and Theoretical Chemistry, Molecular Biology
Abstract: A polarisable ion model is parameterised for the whole series of molten alkali halides by using first-principles calculations based on density functional theory. Viscosity, electrical conductivity and thermal conductivity are determined using molecular dynamics simulations via the Green–Kubo formulae and confronted to experimental results. The calculated transport coefficients are generally in much better agreement than those obtained with the empirical Fumi–Tosi potentials. The inclusion of polarisation effects significantly decreases the viscosity and thermal conductivity, while it increases the electrical conductivity. The individual dynamics of the ions is analysed using the Stokes–Einstein relation. The anion behaviour is always well represented using the slip boundary condition, while for cations there is an apparent shift from slip to stick condition when the ionic radius decreases. This difference is interpreted by subtle changes in their coordinating environment, which are maximised in the case o...
Published: 2015
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34. Structural study of Na2O–B2O3–SiO2 glasses from molecular simulations using a polarizable force field

Author: Thibault Charpentier, Fabien Pacaud, Mathieu Salanne, Laurent Cormier, Jean-Marc Delaye, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Matériaux et Procédés Actifs (LMPA), Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Propriétés des amorphes, liquides et minéraux [IMPMC] (IMPMC_PALM), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CINES, French National HPCOCCIGEN projects x2015097321 and x2016087684, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), and Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)
Subjects: Borosilicate glass, Chemistry, Neutron diffraction, Complex system, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Force field (chemistry), 0104 chemical sciences, Molecular dynamics, Polarizability, Computational chemistry, Chemical physics, Density functional theory, Physical and Theoretical Chemistry, 0210 nano-technology, Boron
Abstract: International audience; Sodium borosilicate glasses Na 2 O–B 2 O 3 –SiO 2 (NBS) are complex systems from a structural point of view. Three main building units are present: tetrahedral SiO 4 and BO 4 (B IV) and triangular BO 3 (B III). One of the salient features of these compounds is the change of the B III /B IV ratio with the alkali concentration, which is very difficult to capture in force fields-based molecular dynamics simulations. In this work, we develop a polarizable force field that is able to reproduce the boron coordination and more generally the structure of several NBS systems in the glass and in the melt. The parameters of the potential are fitted from density functional theory calculations only, in contrast with the existing empirical potentials for NBS systems. This ensures a strong improvement on the transferability of the parameters from one composition to another. Using this new force field, the structure of NBS systems is validated against neutron diffraction and nuclear magnetic resonance experiments. A special focus is given to the distribution of B III /B IV with respect to the composition and the temperature.
Published: 2017
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35. Study of NaF–AlF 3 melts by coupling molecular dynamics, density functional theory, and NMR measurements

Author: Vincent Sarou-Kanian, Mario Burbano, Mathieu Salanne, Catherine Bessada, Sylvian Cadars, Kelly Machado, Didier Zanghi, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Réseau sur le stockage électrochimique de l'énergie (RS2E), Aix Marseille Université (AMU)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Nantes Université (Nantes Univ)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Institut des Matériaux Jean Rouxel (IMN), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN), Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-13-RMNP-0012,MIMINELA,Mécanismes Interfaciaux et Matériaux d'anodes INertes pour l'Electrolyse de l'Aluminium(2013), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Subjects: Chemistry, Chemical shift, Thermodynamics, Ionic bonding, Interatomic potential, 02 engineering and technology, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Ion, Viscosity, Molecular dynamics, General Energy, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Physical chemistry, Density functional theory, Physical and Theoretical Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Improvement of the industrial electrolytic process for aluminum production necessitates a thorough understanding of the underlying ionic structure of the electrolyte, which mainly comprises NaF and AlF3 at around 965 °C. The chemical and physical properties of this melt strongly depend on the aluminum speciation, which requires a multipronged approach in order to clarify its properties. Here we parametrize a new polarizable ion model (PIM) interatomic potential for the molten NaF−AlF3 system, which is used to study the liquid properties up to 50 mol % of AlF$_3$ at high temperatures. The potential parameters are obtained by force fitting to density functional theory (DFT) reference data. Molecular dynamics (MD) simulations are combined with further DFT calculations to determine NMR chemical shifts for $^{27}$Al, $^{23}$Na, and $^{19}$F. An excellent agreement is obtained with experimental values. This enables the study of the dynamic properties of the melts such as viscosity, electrical conductivity, and self-diffusion coefficient.
Published: 2017
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36. Classical Polarizable Force Field to Study Dry Charged Clays and Zeolites

Author: Anne Boutin, Benjamin Rotenberg, Stéphane Tesson, Wilfried Louisfrema, Virginie Marry, Mathieu Salanne, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL)
Subjects: Thermodynamics, 02 engineering and technology, Zeolite faujasite, 010402 general chemistry, Molecular Dynamics, 01 natural sciences, Force field (chemistry), Ion, chemistry.chemical_compound, Molecular dynamics, Computational chemistry, Polarizability, Aluminosilicate, Physical and Theoretical Chemistry, Density Functional Theory, Montmorillonite, Wannier function, Charged Clay, Trans-vacant montmorillonite, 021001 nanoscience & nanotechnology, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Energy, chemistry, Crystal Structure, Density functional theory, Cis-vacant montmorillonite, 0210 nano-technology
Abstract: International audience; We extend the classical Polarizable Ion Model (PIM) to charged clays. We focus on Na-, Ca-, Sr- and Cs-montmorillonite with two types of structures for the octahedral sheet : trans- and cis-vacant. The full set of parameters of the force field is determined by density functional theory calculations, using maximally localized Wannier functions with a force- and dipole-optimization procedure. Simulation results for our polarizable force field are compared to the state-of-the-art non-polarizable flexible force field named Clay Force Field (ClayFF), in order to assess the importance of taking polarization effects into account for the prediction of structural properties. This force field is validated by comparison with experimental data. We also demonstrate the transferability of this force field to other aluminosilicates by considering faujasite-type zeolites and comparing the cation distribution for anhydrous Na, Ca, and Sr Y (and X) faujasites predicted by the PIM model and with experimental data.
Published: 2017
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37. Confinement Effects on an Electron Transfer Reaction in Nanoporous Carbon Electrodes

Author: Trinidad Méndez-Morales, Mathieu Salanne, Mario Burbano, Zhujie Li, Matthieu Haefele, Guillaume Jeanmairet, Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), European Project: 676629,H2020 Pilier Excellent Science,H2020-EINFRA-2015-1,EoCoE(2015), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Nantes Université (Nantes Univ)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), ANR-10-LABX-0076,STORE-EX,Laboratory of excellency for electrochemical energy storage(2010), Maison de la Simulation ( MDLS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX ( PHENIX ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -ESPCI ParisTech-Centre National de la Recherche Scientifique ( CNRS ), Réseau sur le stockage électrochimique de l'énergie ( RS2E ), Centre National de la Recherche Scientifique ( CNRS ), and European Project : 676629,H2020 Pilier Excellent Science,H2020-EINFRA-2015-1,EoCoE ( 2015 )
Subjects: Inorganic chemistry, chemistry.chemical_element, FOS: Physical sciences, 02 engineering and technology, 010402 general chemistry, Electrochemistry, 01 natural sciences, chemistry.chemical_compound, Molecular dynamics, Electron transfer, Physics - Chemical Physics, General Materials Science, Physical and Theoretical Chemistry, Physics::Chemical Physics, [PHYS]Physics [physics], Chemical Physics (physics.chem-ph), Condensed Matter - Materials Science, [ PHYS ] Physics [physics], Nanoporous, Chemistry, Solvation, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, 0104 chemical sciences, 3. Good health, Marcus theory, Chemical physics, Ionic liquid, 0210 nano-technology, Carbon
Abstract: Nanoconfinement generally leads to drastic effect on the physical and chemical properties of ionic liquids. Here we investigate how the electrochemical reactivity in such media may be impacted inside nanoporous carbon electrodes. To this end, we study a simple electron transfer reaction using molecular dynamics simulations. The electrodes are held at constant electric potential by allowing the atomic charges on the carbon atoms to fluctuate. We show that the $\mathrm{Fe^{3+}}/\mathrm{Fe^{2+}}$ couple dissolved in an ionic liquid exhibits a deviation with respect to Marcus theory. This behavior is rationalized by the stabilization of a solvation state of the Fe$^{3+}$ cation in the disordered nanoporous electrode that is not observed in the bulk. The simulation results are fitted with a recently proposed two solvation state model, which allows us to estimate the effect of such a deviation on the kinetics of electron transfer inside nanoporous electrodes., Comment: 8 pages, 10 figures
Published: 2017
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38. Molecular dynamics simulations of Y in silicate melts and implications for trace element partitioning

Author: Sandro Jahn, Volker Haigis, Max Wilke, Sebastian Simon, and Mathieu Salanne
Subjects: Extended X-ray absorption fine structure, Chemistry, Trace element, Mineralogy, Thermodynamics, Thermodynamic integration, 550 - Earth sciences, Geology, 010502 geochemistry & geophysics, 01 natural sciences, Silicate, Gibbs free energy, Bond length, Molecular dynamics, symbols.namesake, chemistry.chemical_compound, Polymerization, Geochemistry and Petrology, 0103 physical sciences, symbols, 010306 general physics, 0105 earth and related environmental sciences
Abstract: Element partitioning depends strongly on composition and structure of the involved phases. In this study, we use molecular dynamics simulations to investigate the local environment of Y as an exemplary trace element in four silicate melts with different compositions and thus varying degrees of polymerization. Based on these structural results, we propose a mechanism which explains the observed partitioning trends of Y and other rare-earth elements between crystals and melts or between two melts. With our computational approach, we found a systematic correlation between melt composition and Y coordination as well as Y―O bond lengths, a result which was corroborated by EXAFS spectroscopy on glasses with the same compositions as the simulated melts. Our simulations revealed, moreover, the affinity of Y for network modifiers as second-nearest neighbors (Ca in this study) and the tendency to avoid network formers (Si and Al). This is consistent with the observation that Y (and other rare-earth elements) in general prefer depolymerized to polymerized melts in partitioning experiments (see, e.g., Schmidt et al. (2006)). Furthermore, we used the method of thermodynamic integration to calculate the Gibbs free energy which governs Y partitioning between two exemplary melts. These more quantitative results, too, are in line with the observed partitioning trends.
Published: 2013
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39. Molecular dynamics simulation of the thermodynamic and transport properties of the molten salt fast reactor fuel LiF–ThF4

Author: Leslie Dewan, Linn W. Hobbs, Mathieu Salanne, Paul A. Madden, and Christian Simon
Subjects: Nuclear and High Energy Physics, Chemistry, Coordination number, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Heat capacity, 0104 chemical sciences, Molecular dynamics, Dipole, Nuclear Energy and Engineering, Polarizability, Electrical resistivity and conductivity, General Materials Science, Molten salt, 0210 nano-technology, Eutectic system
Abstract: The local structure and transport properties of molten LiF-ThF4 at the eutectic composition have been studied at a range of temperatures, using molecular dynamics simulations that incorporate dipole polarization effects. This polarizable interaction potential was parameterized from first-principles calculations. We have calculated the density, self-diffusion coefficients, electrical conductivity, viscosity, and heat capacity at a range of temperatures from 850 K to 1273 K. We have also examined the changes in coordination number as a function of temperature. The simulation results were in good agreement with available experimental data, indicating that such simulations can fulfill a valuable role in augmenting existing experimental work. © 2012 Elsevier B.V. All rights reserved.
Published: 2013
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40. A DFT-Based Aspherical Ion Model for Sodium Aluminosilicate Glasses and Melts

Author: Koichi Shiraki, Kohei Kasahara, Mathieu Salanne, Yoshiki Ishii, Norikazu Ohtori, Thibault Charpentier, Niigata University, Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Structure et Dynamique par Résonance Magnétique (LCF) (LSDRM), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Nippon sheet glass Co, Nippon Sheet Glass Co, Ltd, and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Neutron diffraction, Oxide, Ionic bonding, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Atomic packing factor, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Ion, chemistry.chemical_compound, Molecular dynamics, General Energy, chemistry, 13. Climate action, Aluminosilicate, Chemical physics, Physical and Theoretical Chemistry, 0210 nano-technology, Sodium aluminosilicate
Abstract: International audience; Na + ions play important roles on the physical and chemical properties of aluminosilicate glasses. It is known that they strongly modify the network of tetahedral SiO 4 and AlO 4 units, but the microscopic details on how they alter the local structure remain to be fully established. Here we address this issue by performing classical molecular dynamics simulations over a wide range of glasses compositions. The simulations include atomic polarization and deformation effects through the use of a DFT-parametrized aspherical ion model (AIM), which is carefully validated against experimental data (bond lengths, neutron and X-ray diffraction, and NMR spectroscopy). We show that the structure of the glasses is a subtle interplay between the nature of bridging/nonbridging oxides and the arrangement of Na + ions around them. This reflects, in particular, on the oxide instantaneous dipole moments. ■ INTRODUCTION Durability and mechanical properties of oxide glasses at ambient pressure have attracted much attention from the perspective of material chemistry. 1−11 In particular, in the case of aluminosilicates, the mechanical strength can be further improved through the ion-exchanging procedure on the glass surface, such as in the well-known Corning Gorilla glass. 12,13 Since aluminosilicates in the form of polycrystalline ceramics also show excellent optical property thanks to structural disorder, they are practically used as transparent materials in electrical devices. 14 The dense packing structure of oxide glasses also enables to seal radioactive ions for a long period. 15−18 A key component of functional glasses are alkali and alkaline-earth ions. Because of the weaker character of the bonds they form with oxide ions, in a pure silicate network, they generally create nonbridging oxygens and modify the tetrahedral network topology; they are acting as network modifiers. However, when coexisting with Al 3+ or B 3+ , they can also play the role of charge compensators and assist the formation of four-coordinated cations (tetrahedral AlO 4 or BO 4 units) and bridging oxygens. 11 As a consequence, they increase the packing fraction of the network structure. Due to the difference of strengths between the Si−O/Al−O/B−O bonds on the one hand and the Na−O bonds on the other hand, these oxide materials are often called iono-covalent glasses, even if most of the interactions are very well captured by purely ionic models. 19 Recently, structural and mechanical properties of several aluminosilicate glasses have been extensively investigated using experimental techniques 4,5,8,20,21 and computer simulations. 7,13,22 One of the main remaining challenges is to fully understand the effect of network modifiers on the glass properties. Thereby, a precise atomistic understanding of the nature of ionic bonding in aluminosilicate glasses is important both for fundamental studies and because of their widespread usage in material design. The most intuitive approaches for the experimental determination of atomic structures are X-ray and neutron diffraction, together with EXAFS measurements. 23−37 They are indeed useful techniques for obtaining first coordination shell bond lengths and numbers, although it remains difficult to extract information on the second coordination shell. For such a task, NMR spectroscopy has proven to be a very powerful tool that gives access to the short-and intermediate-range
Published: 2016
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41. ChemInform Abstract: Simulations of Room Temperature Ionic Liquids: from Polarizable to Coarse-Grained Force Fields

Author: Mathieu Salanne
Subjects: chemistry.chemical_compound, Molecular dynamics, chemistry, Force field (physics), Chemical physics, Polarizability, Ionic liquid, Coulomb, Molecule, General Medicine, Polarization (electrochemistry), Ion
Abstract: Room temperature ionic liquids (RTILs) are solvent with unusual properties, which are difficult to characterize experimentally because of their intrinsic complexity (large number of atoms, strong Coulomb interactions). Molecular simulations have therefore been essential in our understanding of these systems. Depending on the target property and on the necessity to account for fine details of the molecular structure of the ions, a large range of simulation techniques are available. Here I focus on classical molecular dynamics, in which the level of complexity of the simulation, and therefore the computational cost, mostly depends on the force field. Depending on the representation of the ions, these are either classified as all-atom or coarse-grained. In addition, all-atom force fields may account for polarization effects if necessary. The most widely used methods for RTILs are described together with their main achievements and limitations.
Published: 2016
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42. From molten salts to room temperature ionic liquids: simulation studies on chloroaluminate systems

Author: Mathieu Salanne, Barbara Kirchner, Paul A. Madden, Ari P. Seitsonen, Leonardo J. A. Siqueira, Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques (PECSA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laborat orio de Materiais H ibridos, Universidade Federal de Sao Paulo, Physikalisch-Chemisches Institut [Zürich], Universität Zürich [Zürich] = University of Zurich (UZH), Department of Materials, University of Oxford, Chemie, Universität Leipzig, Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC), University of Oxford [Oxford], Universität Leipzig [Leipzig], University of Zurich, and Salanne, Mathieu
Subjects: 10120 Department of Chemistry, Aluminium chloride, Materials science, Analytical chemistry, Ionic Liquids, FOS: Physical sciences, Car-Parrinello, Electronic structure, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Chloride, Ion, chemistry.chemical_compound, Molecular dynamics, polarizable force field, Electrical resistivity and conductivity, Physics - Chemical Physics, 540 Chemistry, 0103 physical sciences, RTIL, medicine, Organometallic Compounds, Physical and Theoretical Chemistry, ionic liquid, Chemical Physics (physics.chem-ph), Condensed Matter - Materials Science, Ionic radius, 010304 chemical physics, Temperature, Materials Science (cond-mat.mtrl-sci), molecular dynamics, 0104 chemical sciences, chemistry, Ionic liquid, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Salts, 1606 Physical and Theoretical Chemistry, medicine.drug, Aluminum
Abstract: International audience; An interaction potential including chloride anion polarization effects, constructed from first-principles calculations, is used to examine the structure and transport properties of a series of chloroaluminate melts. A particular emphasis was given to the study of the equimolar mixture of aluminium chloride with 1-ethyl-3-methylimidazolium chloride, which forms a room temperature ionic liquid EMI-AlCl 4. The structure yielded by the classical simulations performed within the framework of the polarizable ion model is compared to the results obtained from entirely electronic structure-based simulations: An excellent agreement between the two flavors of molecular dynamics is observed. When changing the organic cation EMI+ by an inorganic cation with a smaller ionic radius (Li+, Na+, K+), the chloroaluminate speciation becomes more complex, with the formation of Al2Cl 7- in small amounts. The calculated transport properties (diffusion coefficients, electrical conductivity and viscosity) of EMI-AlCl4 are in good agreement with experimental data.
Published: 2016
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43. Calculation of activities of ions in molten salts with potential application to the pyroprocessing of nuclear waste

Author: Christian Simon, Paul A. Madden, Pierre Turq, and Mathieu Salanne
Subjects: Activity coefficient, Quantitative Biology::Biomolecules, Nuclear fission product, Fission products, Chemistry, Inorganic chemistry, Pyroprocessing, Surfaces, Coatings and Films, Ion, Solvent, Molecular dynamics, Materials Chemistry, Physics::Chemical Physics, Physical and Theoretical Chemistry, Molten salt
Abstract: The ability to separate fission products by electrodeposition from molten salts depends, in part, on differences between the interactions of the different fission product cations with the ions present in the molten salt "solvent". These differences may be expressed as ratios of activity coefficients, which depend on the identity of the solvent and other factors. Here, we demonstrate the ability to calculate these activity coefficient ratios using molecular dynamics simulations with sufficient precision to guide the choice of suitable solvent systems in practical applications. We use polarizable ion interaction potentials which have previously been shown to give excellent agreement with structural, transport, and spectroscopic information of the molten salts, and the activity coefficients calculated in this work agree well with experimental data. The activity coefficients are shown to vary systematically with cation size for a set of trivalent cations.
Published: 2016

44. Charge storage in nanoporous carbons: The molecular origin of supercapacitance

Author: Céline Merlet, Clarisse Péan, Mathieu Salanne, Benjamin Rotenberg, PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)
Subjects: Chemical Physics (physics.chem-ph), Supercondensateur, Electrode, Carbone nanoporeux, FOS: Physical sciences, Molecular Dynamics, Nanoporous carbon, Physics - Chemical Physics, Supercapacitors, Adsorption, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Echange ionique, Ion exchange, Simulation moléculaire
Abstract: Supercapacitors are electric devices able to deliver a large power, enabling their use e.g. for the recovery of breaking energy in cars. This is achieved by using two carbon electrodes and an electrolyte solution or a pure ionic liquid (Room Temperature Ionic Liquid, RTIL). Energy is stored by the adsorption of ions at the surface of the electrodes, but the microscopic mechanism underlying the exceptional performance of Carbide Derived Carbon (CDC) electrodes remained unknown. Using molecular simulation with realistic electrode structures and under constant voltage conditions, we investigate the effect of confinement and solvation on the microscopic charging mechanism. We further analyse the dynamics of the charging process and make the link with equivalent circuit models used by electrochemists., in French
Published: 2016

45. Multi-scale modelling of supercapacitors: From molecular simulations to a transmission line model

Author: Mathieu Salanne, Patrice Simon, Clarisse Péan, Benjamin Rotenberg, Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut National de la Recherche en Informatique et en Automatique - INRIA (FRANCE), Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Versailles Saint-Quentin-en-Yvelines -UVSQ (FRANCE), Université de Picardie Jules Verne (FRANCE), Université Paris-Sud 11 (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UPS (FRANCE), Centre Interuniversitaire de Recherche et d'Ingénierie des Matériaux - CIRIMAT (Toulouse, France), Physicochimie des Electrolytes et Nanosystèmes InterfaciauX - PHENIX (Paris, France), Réseau sur le Stockage Electrochimique de l'Energie - RS2E (Amiens, France), and Maison De La Simulation - MDLS (Saclay, France)
Subjects: Materials science, Matériaux, FOS: Physical sciences, Energy Engineering and Power Technology, Thermodynamics, Nanotechnology, 02 engineering and technology, Electrolyte, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Capacitance, Molecular dynamics, Transmission line, Physics - Chemical Physics, Molecular dynamics simulation, Supercapacitors, Porous materials, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Physics::Chemical Physics, Electrical impedance, Chemical Physics (physics.chem-ph), Supercapacitor, [PHYS]Physics [physics], Condensed Matter - Materials Science, Renewable Energy, Sustainability and the Environment, Dynamic processes, Materials Science (cond-mat.mtrl-sci), [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Transport properties, 0210 nano-technology, Porous medium, Voltage
Abstract: We perform molecular dynamics simulations of a typical nanoporous-carbon based supercapacitors. The organic electrolyte consists in 1-ethyl-3-methyl--imidazolium and hexafluorophosphate ions dissolved in acetonitrile. We simulate systems at equilibrium, for various applied voltages. This allows us to determine the relevant thermodynamic (capacitance) and transport (in-pore resistivities) properties. These quantities are then injected in a transmission line model for testing its ability to predict the charging properties of the device. The results from this macroscopic model are in good agreement with non-equilibrium molecular dynamics simulations, which validates its use for interpreting electrochemical impedance experiments., 7 pages, 6 figures
Published: 2016
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46. Understanding the different (dis)charging steps of supercapacitors: influence of potential and solvation

Author: Clarisse Péan, Benjamin Rotenberg, Patrice Simon, Mathieu Salanne, Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), PHysicochimie des Electrolytes et Nanosystèmes InterfaciauX (PHENIX), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Institut National de la Recherche en Informatique et en Automatique - INRIA (FRANCE), Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Subjects: Field (physics), Matériaux, General Chemical Engineering, Nanotechnology, Solvation, 02 engineering and technology, Molecular dynamics, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Energy storage, [SPI.MAT]Engineering Sciences [physics]/Materials, chemistry.chemical_compound, Electrochemistry, Supercapacitors, Porous materials, Supercapacitor, Dynamic processes, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Electrode, Ionic liquid, 0210 nano-technology, Porous medium
Abstract: International audience; Supercapacitors are an innovative and promising technology in the field of energy storage. In the present study, we use modeling via computer simulation as a technique to study the dynamic processes of charging and discharging. This methodology is complementary to experiments. Various model systems composed of different structures of carbon electrodes, in contact with either pure or solvated ionic liquid, polarized at positive or negative potentials were investigated. From the data obtained, we identify several characteristic times for the charging mechanism of supercapacitors. Furthermore, we determine the influence of the structure of the electrode material, and the effects of potential and solvation on dynamical processes.
Published: 2016
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47. Approach of the Molten Salt Chemistry for Aluminium Production: High Temperature NMR Measurements, Molecular Dynamics and DFT Calculations

Author: Mario Burbano, Mathieu Salanne, Catherine Bessada, Vincent Sarou-Kanian, Didier Zanghi, Sylvian Cadars, and Kelly Machado
Subjects: Electrolysis, Molecular dynamics, Chemistry, law, Chemical shift, Inorganic chemistry, First principle, Thermodynamics, Density functional theory, Electrolyte, Nuclear magnetic resonance spectroscopy, Molten salt, law.invention
Abstract: In aluminum production, the electrolyte is a molten fluorides mixture typically around 1000°C. In order to have a better understanding of the industrial process, it is necessary to have a model which will describe the molten salts on a wide range of compositions and temperatures, to accurately cover all the combinations that may be encountered in an operating electrolysis vessel. The aim of this study is to describe the speciation in the electrolyte in terms of anionic species in the bulk materials far from electrodes. To determine the speciation in situ at high temperature in the absence of an electrical field, we develop an original approach combining experimental methods such as Nuclear Magnetic Resonance spectroscopy (NMR) at high temperature with Molecular Dynamics (MD) simulation coupled with first principle calculations based on Density Functional Theory (DFT). This approach allows the calculation of NMR parameters and the comparison with the experimental ones. It will be provide an additional validation and constraint of the model used for MD. We test this approach on the model NaF-AlF3 system.
Published: 2016
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48. Sparse Cyclic Excitations Explain the Low Ionic Conductivity of Stoichiometric Li 7 La

Author: Mathieu Salanne, Dany Carlier, Benjamin J. Morgan, Florent Boucher, and Mario Burbano
Subjects: Materials science, General Physics and Astronomy, chemistry.chemical_element, Interatomic potential, 02 engineering and technology, Electrolyte, 021001 nanoscience & nanotechnology, 01 natural sciences, Ion, Molecular dynamics, Tetragonal crystal system, chemistry, Chemical physics, 0103 physical sciences, Ionic conductivity, Lithium, Atomic physics, 010306 general physics, 0210 nano-technology, Stoichiometry
Abstract: We have performed long time scale molecular dynamics simulations of the cubic and tetragonal phases of the solid lithium-ion electrolyte Li7La3Zr2O12 (LLZO), using a first-principles parametrized interatomic potential. Collective lithium transport was analyzed by identifying dynamical excitations: persistent ion displacements over distances comparable to the separation between lithium sites, and stringlike clusters of ions that undergo cooperative motion. We find that dynamical excitations in c-LLZO (cubic) are frequent, with participating lithium numbers following an exponential distribution, mirroring the dynamics of fragile glasses. In contrast, excitations in t-LLZO (tetragonal) are both temporally and spatially sparse, consisting preferentially of highly concerted lithium motion around closed loops. This qualitative difference is explained as a consequence of lithium ordering in t-LLZO and provides a mechanistic basis for the much lower ionic conductivity of t-LLZO compared to c-LLZO.
Published: 2016
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49. Vibrational Sum Frequency Generation Spectroscopy of the Water Liquid–Vapor Interface from Density Functional Theory-Based Molecular Dynamics Simulations

Author: Michiel Sprik, Marialore Sulpizi, Mathieu Salanne, Marie-Pierre Gaigeot, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques (PECSA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Cambridge [UK] (CAM), Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement (LAMBE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université d'Évry-Val-d'Essonne (UEVE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Johannes Gutenberg - Universität Mainz (JGU), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Université Paris-Seine-Université Paris-Seine-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Infrared, Bulk spectra, 02 engineering and technology, Molecular dynamics, Vibrational sum-frequency generations, 010402 general chemistry, 01 natural sciences, Molecular physics, Spectral line, Interfacial phenomena, Liquid-vapor interface, symbols.namesake, Dipole orientation, Computational chemistry, General Materials Science, Physical and Theoretical Chemistry, Dividing surfaces, Density functionals, Sum-frequency generation, Molecular dynamics simulations, Chemistry, Interfacial water molecules, Thin layers, 021001 nanoscience & nanotechnology, Liquid-vapor, 0104 chemical sciences, Dipole, Imaginary parts, Density functional theory, Vapors, symbols, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], 0210 nano-technology, Raman spectroscopy, Varying thickness, Sum frequency generation spectroscopy
Abstract: International audience; The vibrational sum frequency generation (VSFG) spectrum of the water liquid-vapor (LV) interface is calculated using density functional theory-based molecular dynamics simulations. The real and imaginary parts of the spectrum are in good agreement with the experimental data, and we provide an assignment of the SFG bands according to the dipole orientation of the interfacial water molecules. We use an instantaneous definition of the surface, which is more adapted to the study of interfacial phenomena than the Gibbs dividing surface. By calculating the vibrational (infrared, Raman) properties for interfaces of varying thickness, we show that the bulk spectra signatures appear after a thin layer of 2-3 Å only. We therefore use this value as a criterion for calculating the VSFG spectrum.
Published: 2012
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50. New Coarse-Grained Models of Imidazolium Ionic Liquids for Bulk and Interfacial Molecular Simulations

Author: Céline Merlet, Benjamin Rotenberg, Mathieu Salanne, Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques (PECSA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Tetrafluoroborate, Capacitive sensing, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Force field (chemistry), chemistry.chemical_compound, Molecular dynamics, surface tension, Hexafluorophosphate, Organic chemistry, supercapacitor, Physical and Theoretical Chemistry, Graphite electrode, graphite, force field, [CHIM.MATE]Chemical Sciences/Material chemistry, electrode, 021001 nanoscience & nanotechnology, molecular dynamics, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, General Energy, chemistry, Ionic liquid, 0210 nano-technology
Abstract: International audience; We introduce new coarse-grained models for two imidazolium-based ionic liquids, namely, 1-butyl-3-methyl-imidazolium tetrafluoroborate [BMI][BF4] and 1-ethyl-3-methylimidazolium tetrafluoroborate [EMI][BF4], derived from the original force field of Roy and Maroncelli (J. Phys. Chem. B2010, 114, 12629-12631) representing the 1-butyl-3-methylimidazolium hexafluorophosphate [BMI][PF6] ionic liquid. We evaluate static and dynamic properties between 298 and 500 K and show that they agree with previous experimental and all-atom simulation studies. The models are used to conduct simulations of the liquid-vapor interface and accurately predict surface tensions at 400 K. Capacitive properties are also examined by doing molecular dynamics simulations of the ionic liquids in contact with graphite electrodes. The obtained structures and capacitances are consistent with all-atom simulation results reported on these systems.
Published: 2012
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