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2. Influences from Solvents on Charge Storage in Titanium Carbide MXenes

Author

Wang, Xuehang, primary, Mathis, Tyler S., additional, Li, Ke, additional, Lin, Zifeng, additional, Vlcek, Lukas, additional, Torita, Takeshi, additional, Osti, Naresh C., additional, Hatter, Christine, additional, Urbankowski, Patrick, additional, Sarycheva, Asia, additional, Tyagi, Madhusudan, additional, Mamontov, Eugene, additional, Simon, Patrice, additional, and Gogotsi, Yury, additional

Published
2023
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5. A two-dimensional type I superionic conductor

Author

Rettie, Alexander J. E., Ding, Jingxuan, Zhou, Xiuquan, Johnson, Michael J., Malliakas, Christos D., Osti, Naresh C., Chung, Duck Young, Osborn, Raymond, Delaire, Olivier, Rosenkranz, Stephan, and Kanatzidis, Mercouri G.

Published
2021
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9. Dynamics of polymer electrolyte with LiTFSI via Quasi-Elastic Neutron Scattering

Author

Wang Hui, Osti Naresh C., Allgaier Jürgen, Berg Marcella Cabrera, Halver Rene, Mamontov Eugene, Sutmann Godehard, Doi Yuya, Bucher Nicolas, Egami Takeshi, Förster Stephan, and Ohl Michael

Subjects
Physics, QC1-999
Abstract

Most lithium batteries offer a wide range of applications. However, safety issues are still an unresolved issue for several applications. To solve the safety issue of Li-ion batteries, solid polymer electrolyte is a promising candidate to replace commercial liquid electrolyte. A 4-arm star poly(ethylene oxide) polymer with LiTFSI salt as an electrolyte was studied. The dynamics of this polymer were explored with the Quasi-Elastic Neutron Scattering technique. Furthermore, the influence of temperature and Li salt concentration on the polymer dynamics was investigated. The dynamics of the polymer ends of the arm show much higher flexibility than the core parts making those types of polymers attractive for further studies in battery research.

Published
2023
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11. Influence of Interlayer Cation Ordering on Na Transport in P2-Type Na0.67–xLiyNi0.33–zMn0.67+zO2for Sodium-Ion Batteries

Author

Gabriel, Eric, Wang, Zishen, Singh, Vibhu Vardhan, Graff, Kincaid, Liu, Jue, Koroni, Cyrus, Hou, Dewen, Schwartz, Darin, Li, Cheng, Liu, Juejing, Guo, Xiaofeng, Osti, Naresh C., Ong, Shyue Ping, and Xiong, Hui

Abstract

P2-type Na2/3Ni1/3Mn2/3O2(PNNMO) has been extensively studied because of its desirable electrochemical properties as a positive electrode for sodium-ion batteries. PNNMO exhibits intralayer transition-metal ordering of Ni and Mn and intralayer Na+/vacancy ordering. The Na+/vacancy ordering is often considered a major impediment to fast Na+transport and can be affected by transition-metal ordering. We show by neutron/X-ray diffraction and density functional theory (DFT) calculations that Li doping (Na2/3Li0.05Ni1/3Mn2/3O2, LFN5) promotes ABC-type interplanar Ni/Mn ordering without disrupting the Na+/vacancy ordering and creates low-energy Li–Mn-coordinated diffusion pathways. A structure model is developed to quantitatively identify both the intralayer cation mixing and interlayer cationic stacking fault densities. Quasielastic neutron scattering reveals that the Na+diffusivity in LFN5 is enhanced by an order of magnitude over PNNMO, increasing its capacity at a high current. Na2/3Ni1/4Mn3/4O2(NM13) lacks Na+/vacancy ordering but has diffusivity comparable to that of LFN5. However, NM13 has the smallest capacity at a high current. The high site energy of Mn–Mn-coordinated Na compared to that of Ni–Mn and higher density of Mn–Mn-coordinated Na+sites in NM13 disrupts the connectivity of low-energy Ni–Mn-coordinated diffusion pathways. These results suggest that the interlayer ordering can be tuned through the control of composition, which has an equal or greater impact on Na+diffusion than the Na+/vacancy ordering.

Published
2024
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16. Topology driven and soft phonon mode enabled Na-ion diffusion in quaternary chalcogenides, Na3ZnGaX4 (X = S, and Se).

Author

Kumar, Sajan, Gupta, Mayanak K., Mittal, Ranjan, Sundaramoorthy, Santhoshkumar, Choudhury, Amitava, Osti, Naresh C., Kolesnikov, Alexander I., Stone, Matthew B., Cheng, Yongqiang, and Chaplot, Samrath L.

Abstract

The compounds Na3ZnGaX4 (X = S, Se) are potential solid electrolyte materials in sodium-based batteries, which have certain advantages over oxide materials and have shown significant ionic conductivity at ambient temperature. In this paper, we bring out atomic-level features of the diffusion process in these new materials using the microscopic techniques of inelastic neutron scattering (INS), quasielastic neutron scattering (QENS), and ab initio molecular dynamics (AIMD) simulations. The insights obtained from these techniques are unique and not available from other macroscopic experiments. Neutron scattering experiments have been performed at temperatures from 100 to 700 K. The simulations have been carried out up to 900 K. We have calculated the phonon spectra and the space–time correlation functions and found good agreement with the results of the neutron scattering experiments. The simulations enable detailed analysis of the atomic-site dependent dynamical information. We observe low-energy phonon modes of ∼6 meV involving the vibrations of certain Na atoms in the lattice. This reveals that the Na at 32g Wyckoff sites (Na2) has sufficiently shallow potential among the two available crystallographic sites. This shallow potential facilitates diffusion. Furthermore, the specific structural topology of the network of interconnected zig-zag chains of the Na2 atomic sites provides the low-barrier energy pathways for diffusion. A small fraction of vacancy defects appears essential for diffusion. We further observe that the Na2 atoms undergo jump-like diffusion to the vacant next or the 2nd next neighbour sites at ∼4 Å. While the QENS experiments reveal the jump-like diffusion and its time scale, detailed analysis of the AIMD simulations shows that the jumps appear mostly along zig-zag chains of the Na2 sites in the tetragonal ab-plane, as well as between the chains along the c-axis. The net diffusion is essentially 3-dimensional, with little anisotropy despite the anisotropy of the tetragonal crystal structure. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Understanding curing dynamics of arylacetylene and phthalonitrile thermoset blends.

Author

Laskoski, Matthew, Dyatkin, Boris, Osti, Naresh C., Keum, Jong K., Mamontov, Eugene, and Butler, Tristan

Subjects
BENZENEDICARBONITRILE, CURING, NEUTRON scattering, THERMOSETTING composites, MOLECULAR dynamics, CONSTRUCTION materials
Abstract

Tetrakis(phenylethynyl)benzene (TPEB), a high char yield arylacetylene resin, was blended with a resorcinol‐based PEEK™‐like oligomeric phthalonitrile resin (Res). We observed the influence of each polymer precursor on the structural changes and material dynamics of different mixtures of these resins during thermal curing to produce thermosets with high char retention. We provide insight to help understand fundamental processes that control and tune this complex thermally driven curing mechanism, which, to date, has not been well understood. We show that an equivalent blend of Res and TPEB mitigates the exothermic curing process and exhibits a low viscosity, which may facilitate processing of these thermosetting blends for composite manufacturing. To obtain a more comprehensive overview of the different dynamics of these polymers during curing, we correlated thermodynamic changes with rheology, materials characterization, and molecular dynamics derived from neutron scattering. Our efforts shed more light on the thermally driven chemical changes, physical transformation, and gelation dynamics that drive or accompany softening and curing of these two distinct crosslinking resin groups. [ABSTRACT FROM AUTHOR]

Published
2023
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27. Engineering the Interlayer Spacing by Pre‐Intercalation for High Performance Supercapacitor MXene Electrodes in Room Temperature Ionic Liquid (Adv. Funct. Mater. 33/2021)

Author

Liang, Kun, primary, Matsumoto, Ray A., additional, Zhao, Wei, additional, Osti, Naresh C., additional, Popov, Ivan, additional, Thapaliya, Bishnu P., additional, Fleischmann, Simon, additional, Misra, Sudhajit, additional, Prenger, Kaitlyn, additional, Tyagi, Madhusudan, additional, Mamontov, Eugene, additional, Augustyn, Veronica, additional, Unocic, Raymond R., additional, Sokolov, Alexei P., additional, Dai, Sheng, additional, Cummings, Peter T., additional, and Naguib, Michael, additional

Published
2021
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28. Strongly Anharmonic Phonons and Their Role in Superionic Diffusion and Ultralow Thermal Conductivity of Cu7PSe6.

Author

Gupta, Mayanak K., Ding, Jingxuan, Bansal, Dipanshu, Abernathy, Douglas L., Ehlers, Georg, Osti, Naresh C., Zeier, Wolfgang G., and Delaire, Olivier

Subjects
THERMAL conductivity, PHONONS, INELASTIC neutron scattering, ACOUSTIC phonons, PHONON scattering, NEUTRON scattering, LATTICE dynamics
Abstract

The quest for advanced superionic materials requires understanding their complex atomic dynamics, but detailed studies of the interplay between lattice vibrations and ionic diffusion remain scarce. Here inelastic and quasielastic neutron scattering measurements in the superionic argyrodite Cu7PSe6 are reported, combined with molecular dynamics (MD) based on ab initio and machine‐learned potentials, providing critical insights into the atomistic mechanisms underlying fast ion conduction. The results reveal how long‐range Cu diffusion is limited by intercluster hopping, controlled by selective anharmonic phonons of the crystalline framework. Further, the Green–Kubo simulations reproduce the ultralow lattice thermal conductivity and identify contributions from mobile ions, phonons, and their cross‐correlations. The mode resolved analysis shows that the thermal conductivity is dominated by low‐energy acoustic phonon modes of the overall crystal framework. The analysis of mode‐resolved spectral functions further show that vibrational modes with significant Cu contributions are strongly damped, corresponding to the breakdown of associated phonon quasiparticles. These results highlight the importance of strongly anharmonic effects in superionic systems, in which the traditional quasiharmonic phonon picture is insufficient, and pave the way toward combining machine‐learning accelerated simulations with neutron scattering experiments to rationalize the complex atomic dynamics underlying ionic and thermal transport. [ABSTRACT FROM AUTHOR]

Published
2022
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33. Association of a multifunctional ionic block copolymer in a selective solvent.

Author

Etampawala, Thusitha N., Aryal, Dipak, Osti, Naresh C., Lilin He, Heller, William T., Willis, Carl L., Grest, Gary S., and Perahia, Dvora

Subjects
MOLECULAR self-assembly, SMALL-angle neutron scattering, BLOCK copolymers, SOLUTION (Chemistry), SULFONATION, CHEMICAL decomposition
Abstract

The self-assembly of multiblock copolymers in solutions is controlled by a delicate balance between inherent phase segregation due to incompatibility of the blocks and the interaction of the individual blocks with the solvent. The current study elucidates the association of pentablock copolymers in a mixture of selective solvents which are good for the hydrophobic segments and poor for the hydrophilic blocks using small angle neutron scattering (SANS). The pentablock consists of a center block of randomly sulfonated polystyrene, designed for transport, tethered to poly-ethylene-r-propylene and end-capped by poly-t-butyl styrene, for mechanical stability. We find that the pentablock forms ellipsoidal core-shell micelles with the sulfonated polystyrene in the core and Gaussian decaying chains of swollen poly-ethylene-r-propylene and poly-t-butyl styrene tertiary in the corona. With increasing solution concentration, the size of the micelle, the thickness of the corona, and the aggregation number increase, while the solvent fraction in the core decreases. In dilute solution the micelle increases in size as the temperature is increased, however, temperature effects dissipate with increasing solution concentration. [ABSTRACT FROM AUTHOR]

Published
2016
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38. Discovery of a Two-Dimensional Type I Superionic Conductor

Author

Rettie, Alex, primary, Ding, Jingxuan, primary, Johnson, Michael, primary, Malliakas, Christos, primary, Osti, Naresh, primary, Chung, Duck Young, primary, Osborn, Raymond, primary, Delaire, Olivier, primary, Rosenkranz, Stephan, primary, and Kanatzidis, Mercouri, primary

Published
2020
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41. Multiscale and Multimodal Characterization of 2D Titanium Carbonitride MXene

Author

Sun, Weiwei, primary, Wang, Hsiu‐Wen, additional, Vlcek, Lukas, additional, Peng, Jing, additional, Brady, Alexander B., additional, Osti, Naresh C., additional, Mamontov, Eugene, additional, Tyagi, Madhusudan, additional, Nanda, Jagjit, additional, Greenbaum, Steven G., additional, Kent, Paul R. C., additional, and Naguib, Michael, additional

Published
2020
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42. Critical Role of Anion–Solvent Interactions for Dynamics of Solvent-in-Salt Solutions

Author

Popov, Ivan, primary, Sacci, Robert L., additional, Sanders, Nicolette C., additional, Matsumoto, Ray A., additional, Thompson, Matthew W., additional, Osti, Naresh C., additional, Kobayashi, Takeshi, additional, Tyagi, Madhusudan, additional, Mamontov, Eugene, additional, Pruski, Marek, additional, Cummings, Peter T., additional, and Sokolov, Alexei P., additional

Published
2020
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46. Confined Interlayer Water Promotes Structural Stability for High-Rate Electrochemical Proton Intercalation in Tungsten Oxide Hydrates

Author

Mitchell, James B., primary, Geise, Natalie R., additional, Paterson, Alisa R., additional, Osti, Naresh C., additional, Sun, Yangyunli, additional, Fleischmann, Simon, additional, Zhang, Rui, additional, Madsen, Louis A., additional, Toney, Michael F., additional, Jiang, De-en, additional, Kolesnikov, Alexander I., additional, Mamontov, Eugene, additional, and Augustyn, Veronica, additional

Published
2019
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