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The interaction of Ca evaporated in vacuum onto a 2H–NbSe2 surface held at room temperature was studied by photoelectron spectroscopy. Indications of an intercalation reaction were observed initially, but larger Ca depositions resulted in a layer-breaking reaction producing a disordered overlayer of varying compositions. The layer-breaking reaction is likely due to the intercalation compound becoming unstable as the local Ca concentration exceeds the threshold value. Continued Ca depositions eventually resulted in the growth of three-dimensional islands of Ca metal, exposing relatively unaffected NbSe2 layers between the Ca islands. [ABSTRACT FROM AUTHOR]

The typical metal chloride‐graphite intercalation compounds (MC‐GICs) inherit intercalation capacity, high charge conductivity, and high tap density from graphite, and these are considered as one of the promising alternatives of graphite anode in rechargeable metal‐ion batteries (MIBs). Notably, the special interlayer decoupling effects and the introduction of extra conversion capacity by metal chloride could greatly break the capacity limitation of graphite anodes and achieve higher energy density in MIBs. The optimization of both graphite host and metal chloride species with specific structures endows MC‐GICs with design feasibility for different application requirements of different MIBs, such as several times the actual capacity compared to graphite anodes, rapid migration of large carriers, and other properties. Herein, a brief review has been provided with the latest understanding of conductivity characteristics and energy storage mechanisms of MC‐GICs and their interesting performance features of full potential application in rechargeable MIBs. Based on the existing research of MC‐GICs, necessary improvements and prospects in the near future have been put forward. [ABSTRACT FROM AUTHOR]

Herein, initially, we present a general overview of the global financial support for chemistry devoted to materials science, specifically intercalation layered compounds (ILCs). Subsequently, the strategies to synthesise these host structures and the corresponding guest-host hybrid assemblies are exemplified on the basis of some families of materials, including pillared clays (PILCs), porous clay heterostructures (PCHs), zirconium phosphate (ZrP), layered double hydroxides (LDHs), graphite intercalation compounds (GICs), graphene-based materials, and MXenes. Additionally, a non-exhaustive survey on their possible application in the field of energy through electrochemical storage, mostly as electrode materials but also as electrolyte additives, is presented, including lithium technologies based on lithium ion batteries (LIBs), and beyond LiBs with a focus on possible alternatives such XIBs (X = Na (NIB), K (KIB), Al (AIB), Zn (ZIB), and Cl (CIB)), reversible Mg batteries (RMBs), dual-ion batteries (DIBs), Zn-air and Zn-sulphur batteries and supercapacitors as well as their relevance in other fields related to (opto)electronics. This selective panorama should help readers better understand the reason why ILCs are expected to meet the challenge of tomorrow as electrode materials. [ABSTRACT FROM AUTHOR]

Owing to the crustal abundance of sodium element, sodium ion batteries (SIBs) are considered a promising complementary to lithium‐ion battery for stationary energy storage applications. The cointercalation chemistry enables the use of cost‐effective graphite as anodes, whereas the low capacity (<130 mAh g−1) and high redox potential (>0.6 V vs. Na/Na+) of graphite significantly limit the energy density of SIBs. Herein, we induce the high‐capacity Na metal into sodiophilic ternary graphite intercalation compounds (t‐GICs) via co‐intercalation and deposition reactions, thereby achieving Na/t‐GIC anodes with high capacities and low working voltage (0.18 V). The new anodes exhibit high coulombic efficiencies of above 99.7 % over 550 cycles and a high‐rate capacity of 588.4 mAh g−1 at 6 C (10 min per charge). When it is paired with Na3V2(PO4)2F3 (NVPF) cathodes, the SIBs demonstrate a high energy density of 259 Wh kg−1both electrodes surpassing that of commercial LiFePO4//graphite batteries. The outstanding anode performance is attributed to the tailored sodiophilicity of graphite through manipulating the ether solvents and the in situ generated space among t‐GIC flakes to stably accommodate Na metal. Our findings for stable Na plating/striping on sodiophilic graphite materials provide an effective approach for developing advanced SIBs. [ABSTRACT FROM AUTHOR]

Defect engineering is an effective strategy to improve the electrochemical and electrocatalytic properties of transition metal oxide-based electrode materials. In this work, NH4+ ion intercalated MnO2 nanoflowers (C-A-MnO2) were prepared from hydrothermally synthesized manganese dioxide (MnO2) using a simple temperature-controlled method, in which oxygen vacancies on/inside the C-A-MnO2 nanoflowers were generated by the reduction of Mn4+ species by NH4+ ions. The electrical conductivity and electrochemical properties were improved by modulating the content of oxygen vacancies. In addition, the intercalation of NH4+ ions further enlarged the layer spacing of MnO2, obtaining a larger specific surface area, exposing more active sites, and shortening the electron/ion transport paths. The specific capacitance of the 1 M-A-MnO2 samples exhibited a significant enhancement (from 182.2 F g−1 to 252.2 F g−1 at a current density of 0.5 A g−1). An ASC device (1 M-A-MnO2//La-MoO3/GQD) with an operating voltage of 1.9 V was assembled. The energy density of the device was 66.66 W h kg−1 at a power density of 475 W kg−1. 1 M-A-MnO2 also exhibited excellent cycling stability with 94.3% capacitance retention after 8000 cycles. Meanwhile, it exhibited a low overpotential (361 mV at 10 mA cm−2) and Tafel slope (61 mV dec−1) as the oxygen evolution reaction (OER) electrocatalyst. Thus, this work provides valuable insights for rational intercalation of NH4+ ions for controlled synthesis of supercapacitor electrode materials and OER catalysts. [ABSTRACT FROM AUTHOR]

Exfoliated graphite (EG) is a promising macroporous sorbent for oils and liquid hydrocarbons on water surfaces. The preparation of EG includes a synthesis of graphite intercalation compounds, expandable graphite and its thermal exfoliation. The structure of the initial graphite intercalation compound (GIC) has a significant influence on the structure of exfoliated graphite and its sorption properties: sorption capacity and selectivity of water/octane sorption. Thus, the aim of this work was to investigate the relationship between the structure of EG based on 1st stage, 2nd stage, 3rd stage, 4th stage GICs and EG sorption properties and water wettability. The influence of the GIC stage number on the EG sorption and surface properties is studied. EG obtained from 1st stage GIC at 1000 °C is characterized by a higher sorption capacity toward octane than EG from 4th stage GIC. The selectivity of octane/water sorption reduces when decreasing the GIC stage number from 4 to 1. The high sorption of water can be explained by a higher surface area of EG and the presence of remaining oxygen groups on the edges of graphite crystallites in the EG structure. The EG structure was investigated by XRD, SEM, nitrogen adsorption–desorption method, FTIR and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered materials have been studied in depth during the past two decades due to their unique structure and properties. Transition metal (TM) intercalation of layered materials have been proven as an effective way to introduce new physical properties, such as tunable 2D magnetism, but the direct growth of atomically thin heteroatoms-intercalated layered materials remains untapped. Herein, we directly synthesize various ultrathin heteroatoms-intercalated 2D layered materials (UHI-2DMs) through flux-assisted growth (FAG) approach. Eight UHI-2DMs (V1/3NbS2, Cr1/3NbS2, Mn1/3NbS2, Fe1/3NbS2, Co1/3NbS2, Co1/3NbSe2, Fe1/3TaS2, Fe1/4TaS2) were successfully synthesized. Their thickness can be reduced to the thinnest limit (bilayer 2D material with monolayer intercalated TM), and magnetic ordering can be induced in the synthesized structures. Interestingly, due to the possible anisotropy-stabilized long-range ferromagnetism in Fe1/3TaS2 with weak interlayer coupling, the layer-independent magnetic ordering temperature of Fe1/3TaS2 was revealed by magneto-transport properties. This work establishes a general method for direct synthesis of heteroatom-intercalated ultrathin 2D materials with tunable chemical and physical properties. The intercalation of heteroatoms has been demonstrated to be an effective approach to introduce new physical properties in 2D layered materials (2DMs). Here, the authors report a flux-assisted growth method to synthesize various ultrathin heteroatoms-intercalated 2DMs, showing evidence of anisotropy-stabilized long-range ferromagnetism in Fe1/3TaS2. [ABSTRACT FROM AUTHOR]

The purpose of the work is to establish the possibility of obtaining expanded graphite of high purity (carbon content more than 99.5 % wt.) from flotation-enriched graphite (carbon content 94–97 % wt.) by combining into one process intercalation of graphite with a solution of potassium dichromate in concentrated sulfuric acid with subsequent hydrolysis, and chemical purification using solutions of ammonium bifluoride in sulfuric or hydrochloric acid and Trilon B in an alkaline buffer as purification reagents, and to confirm this possibility by quantum chemical calculations. It has been experimentally shown that combining oxidized graphite synthesis and its chemical purification into one process allows obtaining expanded graphite of high purity, with a carbon content of 99.75–99.85 % wt. The methods of X-ray diffraction and thermogravimetry show that the interaction of oxidized graphite (the residual compound of intercalation of graphite with sulfuric acid) with cleaning reagents does not reduce the ability to expand. The magnitude of the mass loss of oxidized graphite according to various variants of chemical post-cleaning and the temperature range of such loss remain practically unchanged. Quantum chemical calculations of the adsorption energy (∆Eads) of one molecule of Trilon B on the surface of a graphene-like plane (GLP), the complexation reaction of metal sulfates, the energy effect of the interaction of Trilon B with sulfates of alkaline earth metals in an aqueous solution, and with the participation of the surface of the graphene plane were carried out using the GAMESS (US) program by the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d,p) basis set, taking into account the Grimme D3 dispersion correction within the PCM polarizable continuum. The results of the analysis of quantum chemical calculations indicate that the Trilon B molecule is better physically sorbed on the oxidized GLP (–412 kJ/mol) than on its native form (–188 kJ/mol). The values of the energy effect of the complexation of magnesium and calcium cations with Trilon B have a negative value both in an aqueous solution and in the presence of the oxidized form of GLP. This indicates the thermodynamic probability of this process, which is consistent with the experimental results. Regardless of the nature of the cation, its interaction with Trilon B is thermodynamically more likely in an aqueous solution than in the adsorbed state on the surface of oxidized GLP. [ABSTRACT FROM AUTHOR]

Silicon-carbon materials have broad development prospects as negative electrode materials for lithium-ion batteries. In this paper, polyvinyl butyral (PVB)-based carbon-coated silicon (Si/C) composite materials were prepared using PVB-coated Si particles and then high-temperature carbonization methods. Furthermore, the PVB-based carbon-coated silicon/artificial graphite composite materials (Si/C-Gr) were prepared by using artificial graphite as conductive skeleton. And the electrochemical and battery performances of Si/C and Si/C-Gr composite materials as negative electrode materials of lithium-ion batteries were investigated in detail. The results showed that PVB-based carbon was uniformly coated on the surface of silicon particles, and the electrochemical performance and battery performance of the Si/C composite material was improved with the increasing proportion of PVB in the reaction feed. With the introduction of artificial graphite, the constructed ternary composite of Si/C-Gr as anode exhibited a further improved electrochemical performances, such as cycling stability, rate performance, and coulombic efficiency. Specially, the Si/C-Gr (1:30:0.7) composite anode has a discharge specific capacity of 1239.9 mAh/g in the first cycle and 922.9 mAh/g in the 100th cycles at a current density of 0.1 A/g. And the corresponding coulombic efficiency was 84.5% in the first cycle and maintained at around 98% after 100 cycles. The average discharge specific capacity was 1045.5, 796.08, 688.75, 507.09, and 479.11 mAh/g at the current rate of 0.1, 0.2, 0.4, 0.8, and 1 A/g, respectively. This is attributed to the addition of artificial graphite forming an effective conductive skeleton structure, which enhanced the structural stability of the composite material and improved the electronic conductivity of the electrode material. Also, PVB as functional coating polymer improved the dispersion of Si particles on the surface of graphite. All above reasons enabled the electrode materials to have good electrochemical performances. [ABSTRACT FROM AUTHOR]

Faced with the increasing volume of retired lithium-ion batteries (LIBs), recycling and reusing the spent graphite (SG) is of great significance for resource sustainability. Here, a facile method for transforming the SG into a carbon framework as well as loading Fe2O3 to form a composite anode with a sandwich structure is proposed. Taking advantage of the fact that the layer spacing of the spent graphite naturally expands, impurities and intercalants are eliminated through microwave thermal shock to produce microwave-puffed graphite (MPG) with a distinct three-dimensional structure. Based on the mechanism of microwave-induced gasification intercalation, a Fe2O3-MPG intercalation compound (Fe2O3-MPGIC) anode material was constructed by introducing iron precursors between the framework layers and subsequently converting them into Fe2O3 through annealing. The Fe2O3-MPGIC anode exhibits a high reversible capacity of 1000.6 mAh g-1 at 200 mA g-1 after 100 cycles and a good cycling stability of 504.4 mAh g-1 at 2000 mA g-1 after 500 cycles. This work can provide a reference for the feasible recycling of SG and development of high-performance anode materials for LIBs. [ABSTRACT FROM AUTHOR]

Transition-metal dichalcogenides (TMDCs) have been investigated for their versatile properties and remarkable tunability. Recently, there has been a resurgence of interest in magnetically intercalated TMDCs, driven by their potential applications in spintronic devices. In this paper, we describe a novel high-pressure synthesis procedure, yielding nominal NixTi2S4 compositions in a one-step straightforward procedure, starting from TiS2 and Ni metal. According to the Rietveld-refined synchrotron X-ray diffraction data, the compound crystallizes into a trigonal space group P3¯m1 (No. 164) with a crystallographic formula of Ni0.8Ti2S4. We observe anomalies in the thermal evolution of the Ni–S pair-bond at ∼8 K, which were correlated to a minor deviation of ∼0.05% below 25 K from the Grüneisen model for the zero-pressure equation of state that describes the thermal expansion of the unit-cell volume. Extended X-ray absorption fine structure (EXAFS) analysis probed the local atomic dynamics surrounding the Ni atoms (Ni K-edge). A careful examination of the bond variance in paths within the first shell indicated an increase in the covalent bonding between Ni and Ti, in contrast to other intercalated sulfides such as FexTi2S4. The investigated magnetic properties and specific heat do not demonstrate a long-range magnetic order. Instead, we observed a cluster glass-like behavior around 16 K, which suggests the coexistence of anti/ferromagnetic short-range magnetic interactions at low temperatures mediated by electron hopping between Ni eg states due to magnetic frustration in the system. The local atomic arrangement correlates to the short-range magnetic interactions, which suggests the occurrence of magnetoelastic coupling in Ni0.8Ti2S4. [ABSTRACT FROM AUTHOR]

Co‐intercalation reactions make graphite a feasible anode in Ca ion batteries, yet the correlation between Ca ion intercalation behaviors and electrolyte structure remains unclear. This study, for the first time, elucidates the pivotal role of anions in modulating the Ca ion solvation structures and their subsequent intercalation into graphite. Specifically, the electrostatic interactions between Ca ion and anions govern the configurations of solvated‐Ca‐ion in dimethylacetamide‐based electrolytes and graphite intercalation compounds. Among the anions considered (BH4−, ClO4−, TFSI− and [B(hfip)4]−), the coordination of four solvent molecules per Ca ion (CN=4) leads to the highest reversible capacities and the fastest reaction kinetics in graphite. Our study illuminates the origins of the distinct Ca ion intercalation behaviors across various anion‐modulated electrolytes, employing a blend of experimental and theoretical approaches. Importantly, the practical viability of graphite anodes in Ca‐ion full cells is confirmed, showing significant promise for advanced energy storage systems. [ABSTRACT FROM AUTHOR]

The temperature-dependent magnetic susceptibility combined with first-principle calculations was conducted to unravel the magnetic structure and the magnetic interaction of the laminar structure of manganese diboride (MnB2). MnB2 showed weak ferromagnetic, antiferromagnetic, and paramagnetic behavior with increased temperature. Its weak ferromagnetic property below 135.6 K Curie temperature (TC) originated from the spin canting antiferromagnetic magnetic structure. The exotic kink of temperature-dependent magnetic susceptibility at 330 K Néel temperature (TN) correlated with the transition from antiferromagnetic to paramagnetic structure. First-principle calculation show that the antiferromagnetic ordering show lower energy, and suggest a canting anti-ferromagnetic ordering for its ferromagnetic behavior. The peculiar magnetic behavior of MnB2 may be due to the insertion of the honeycomb boron layers into the host matrix of manganese atoms. The honeycomb boron layers played a key role in the exchange between two manganese layers. This study resolved the longstanding puzzle of the magnetic structure of MnB2 and provided a typical laminar magnetic structure prototype. [ABSTRACT FROM AUTHOR]

Abstract The typical metal chloride‐graphite intercalation compounds (MC‐GICs) inherit intercalation capacity, high charge conductivity, and high tap density from graphite, and these are considered as one of the promising alternatives of graphite anode in rechargeable metal‐ion batteries (MIBs). Notably, the special interlayer decoupling effects and the introduction of extra conversion capacity by metal chloride could greatly break the capacity limitation of graphite anodes and achieve higher energy density in MIBs. The optimization of both graphite host and metal chloride species with specific structures endows MC‐GICs with design feasibility for different application requirements of different MIBs, such as several times the actual capacity compared to graphite anodes, rapid migration of large carriers, and other properties. Herein, a brief review has been provided with the latest understanding of conductivity characteristics and energy storage mechanisms of MC‐GICs and their interesting performance features of full potential application in rechargeable MIBs. Based on the existing research of MC‐GICs, necessary improvements and prospects in the near future have been put forward.

Using classical molecular dynamics simulations, we investigate the dielectric properties at interfaces of water with graphene, graphite, hexane, and water vapor. For graphite, we compare metallic and nonmetallic versions. At the vapor–liquid water and hexane–water interfaces, the laterally averaged dielectric profiles are significantly broadened due to interfacial roughness and only slightly anisotropic. In contrast, at the rigid graphene surface, the dielectric profiles are strongly anisotropic and the perpendicular dielectric profile exhibits pronounced oscillations and sign changes. The interfacial dielectric excess, characterized by the shift of the dielectric dividing surface with respect to the Gibbs dividing surface, is positive for all surfaces, showing that water has an enhanced dielectric response at hydrophobic surfaces. The dielectric dividing surface positions vary significantly among the different surfaces, which points to pronounced surface-specific dielectric behavior. The interfacial repulsion of a chloride ion is shown to be dominated by electrostatic interactions for the soft fluid–fluid interfaces and by non-electrostatic Lennard-Jones interactions for the rigid graphene–water interface. A linear tensorial dielectric model for the ion–interface interaction with sharp dielectric interfaces located on the dielectric dividing surface positions works well for graphene but fails for vapor and hexane, because these interfaces are smeared out. The repulsion of chloride from the metallic and nonmetallic graphite versions differs very little, which reflects the almost identical interfacial water structure and can be understood based on linear continuum dielectric theory. Interface flexibility shows up mostly in the nonlinear Coulomb part of the ion–interface interaction, which changes significantly close to the interfaces and signals the breakdown of linear dielectric continuum theory. [ABSTRACT FROM AUTHOR]

Mastering graphene preparation is an essential step to its integration into practical applications. For large‐scale purposes, full graphite exfoliation appears as a suitable route for graphene production. However, it requires overpowering attractive van der Waals forces demanding large energy input, with the risk of introducing defects in the material. This difficulty can be overcome by using graphite intercalation compounds (GICs) as starting material. The greater inter‐sheet separation in GICs (compared with graphite) allows the gentler exfoliation of soluble graphenide (reduced graphene) flakes. A solvent exchange strategy, accompanied by the oxidation of graphenide to graphene, can be implemented to produce stable aqueous graphene dispersions (Eau de graphene, EdG), which can be readily incorporated into many processes or materials. In this work, we prove that electrostatic forces are responsible for the stability of fully exfoliated graphene in water, and explore the influence of the oxidation and solvent exchange procedures on the quality and stability of EdG. We show that the amount of defects in graphene is limited if graphenide oxidation is carried out before exposing the material to water, and that gas removal of water before the incorporation of pre‐oxidized graphene is advantageous for the long‐term stability of EdG. [ABSTRACT FROM AUTHOR]

This work aims to study the insertion of AlCl4−$\text{AlCl}_{4}^{-}$ anion in the crystalline structure of oriented pyrolytic graphite (PG) at the point of view of the anion itself. The electronic and atomic structures of the anion at different intercalation stages are studied. In particular double‐edge (bicolor) X‐ray absorption spectroscopy at the Al and Cl K‐edges is carried out, highlighting a contraction of the anion bonding at the highest intercalation degree obtained electrochemically (stage 3), while the electronic population changes for both the edges upon cycle. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) are the materials that can absorb and release energy during their phase transition. The materials have become ubiquitous but still face challenges. The inevitable transition from solid phase to liquid phase in these materials during operation limits their utility in application areas that require leak-proof properties like orthopaedic mattresses or gel packs, or applications requiring self-load-bearing capabilities (such as ceiling tiles and building walls). Entrapment of PCM in porous matrices is one of the promising methods of capturing the PCM and limiting the flow of materials in the liquid phase. The present study discusses the preparation of exfoliated graphite from commercially available intercalated graphite. The process of exfoliating the intercalated graphite has been holistically characterized using x-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The graphite with a surface area of 47.37 cc/g with a purity of 99% was found to have a maximum absorption of 80% (w/w) stearic acid as PCM. In addition, this paper investigates two synthetic routes to prepare the shape-stabilized PCM. The blends are characterized and compared along six indicators: transition point, latent heat capacity, thermal conductivity, exudation behavior, FTIR, and SEM. Composite 1 refers to stearic acid absorbed in the exfoliated graphite. Composite 2 refers to the stearic acid absorbed in exfoliated graphite which is further treated with an elastomer SEBS. The leak test performed on both blends signifies that SEBS is an essential ingredient. The PCM composition optimized in this study can unlock various thermal applications with critical requirements where direct exposure of chemicals to the user is unacceptable. Further, the study itself is envisaged to serve as a framework to develop enhanced shape-stabilized PCMs with tuneable thermal conductivity and extended operation life in application areas where leakage in liquid phase is a concern. [ABSTRACT FROM AUTHOR]

Intercalation of layered materials offers an effective approach for tunning their structures and generating unprecedented properties. The multiple van der Waals (vdW) gap combined with long‐range ordering guests can change the interaction of layered host materials and electromagnetic field. Herein, a chemical‐scissor intercalation protocol medicated by molten salt is proposed for tailing the electromagnetic properties of transitional metal dichalcogenides (TMDCs). NbS2 is functional intercalated by heteroatoms (Fe, Co, Ni). The intercalated NbS2 with superlattice exhibit improved dielectric properties due to the reduced Brillouin zone size and the local electron distribution. Both the computational and experimental investigations indicate enhanced electron transport and additional polarized centers caused by intercalation. Overall, this work shows the great potential of structure editing of vdW materials, whilst intercalation via the chemical scissor in molten salts is considered a feasible intercalation strategy to further enrich their applications. [ABSTRACT FROM AUTHOR]

Surface Enhanced Raman spectroscopy (SERS) is a molecular‐specific analytical technique with various applications. Although electromagnetic (EM) and chemical (CM) mechanisms have been proposed to be the main origins of SERS, exploring highly sensitive SERS substrates with well‐defined mechanistic pathways remains challenging. Since surface and electronic structures of substrates were crucial for SERS activity, zero‐valent transition metals (Fe and Cu) were intercalated into MoO3 to modulate its surface and electronic structures, leading to unexceptional high enhancement factors (1.0×108 and 1.1×1010 for Fe‐MoO3 and Cu‐MoO3, respectively) with decent reproducibility and stability. Interestingly, different mechanistic pathways (CM and EM) were proposed for Fe‐MoO3 and Cu‐MoO3 according to mechanistic investigations. The different mechanisms of Fe‐MoO3 and Cu‐MoO3 were rationalized by the electronic structures of the intercalated Fe(0) and Cu(0), which modulates the surface and electronic structures of Fe‐MoO3 and Cu‐MoO3 to differentiate their SERS mechanisms. [ABSTRACT FROM AUTHOR]

Graphite‐based dual‐ion batteries are with potential higher energy density, making them a unique candidate in energy storage systems. However, anion insertion into graphite in aqueous environment remains a significant challenge. Herein, we report that the reversible insertion of Al‐Cl superhalide into expanded graphite (EG) delivers an ultrahigh specific capacity of ~171 mAh g−1 from an aqueous deep eutectic solvent (DES) gel electrolyte of 50 m ChCl+5 m AlCl3. High‐resolution transmission electron microscopy (HRTEM), Raman spectra and X‐ray diffraction (XRD) show that the EG generates turbostratic structure during Al‐Cl superhalide (de)insertion instead of presenting typical graphite intercalation compounds (GIC), thus attributing to the high capacity during Al‐Cl superhalide insertion. [ABSTRACT FROM AUTHOR]

Co‐intercalation using ether‐based electrolytes renders graphite as a promising anode material in sodium‐ion batteries (SIBs). While most research on electrochemical solvent co‐intercalation in graphite has focused on linear ethers such as mono‐, di‐, tri‐, tetra‐, and penta‐glyme, we herein investigate the possibility of reversible electrochemical co‐intercalation with alternative solvents, especially cyclic ethers tetrahydrofuran (THF) and 1,3‐dioxolane (DOL), which show no signs of co‐intercalation on their own. We demonstrate, however, that this reaction becomes feasible when incorporating diethylene glycol dimethyl ether (2G, diglyme) as an additive. Operando X‐ray diffraction and ex‐situ ss‐NMR techniques are employed comprehensively to understand the co‐intercalation reaction of these cyclic ethers, along with Na+‐glymes, into graphite during cycling. When using these mixed electrolytes i. e., THF/2G and DOL/2G, the voltage profiles changes compared to the pure glyme‐based electrolyte, while showing comparable specific capacities and good long‐term durability. Overall, we propose that even trace amounts of diglyme prompt the co‐intercalation of THF and DOL into graphite layers. This leads to the formation of quaternary graphite intercalation compounds (q‐GICs), expanding beyond the realm of ternary graphite intercalation compounds (t‐GICs). [ABSTRACT FROM AUTHOR]

In this work, the Li ordering and its influence on Li intercalation and plating on graphite, bilayer, and single-layer graphene are investigated by first-principles calculation with two-dimensional cluster expansion and van der Waals corrections. The results show that Li intercalation has a multistage feature for graphite and bilayer graphene at Li concentrations from C2 to LiC6. Beyond LiC6, Li atoms are crowded in graphite and bilayer graphene, resulting in a negative discharge voltage. The calculated overpotential indicates Li plating easily happens on graphite but is unlikely on bilayer graphene. For single-layer graphene, Li atoms uniformly cover the graphene surface from C2 to LiC4 with the presence of voltage stages, while forming an atomic island at a higher Li concentration. Our findings not only give a good recount on recent Li plating phenomena in Li-ion batteries but also provide a rationale for circumventing those side reactions on graphene and its variants. [ABSTRACT FROM AUTHOR]

Geometric and electronic structures of a corannulene ( C 20 H 10) intercalated bilayer graphene are investigated in terms of the molecular conformation using density functional theory. Our calculations indicate that the electronic structure of bilayer graphene is tunable by controlling the molecular conformation of corannulene. Holes and electrons coexist on the upper and lower layers of graphene, which are situated at the convex region and edge of corannulene when it has the bowl conformation. In contrast, bilayer graphene has a tiny gap of 4.7 meV at the K point owing to the substantial interaction between graphene and corannulene when corannulene has flat conformation. Electron and hole redistribution in bilayer graphene intercalating corannulene indicated the possibility of all carbon p-n border at an interface between corannulene with convex and concave arrangements. The intercalation substantially decreases the energy difference between the ground state bowl conformation and the metastable state flat conformation by approximately 400 meV. Accordingly, the two-dimensional nano-spacing between the graphene layers changes the molecular conformation of corannulene from a bowl to a flat structure at 139 MPa. [ABSTRACT FROM AUTHOR]

Seeking new cathode chemistry with high onset potential and compatibility with electrolytes has become a challenge for aqueous Zn ion batteries. Anion intercalation in graphite (4.5 V vs Li+/Li) possesses the potentiality but usually shows a competitive relationship with oxygen evolution reaction (OER) in aqueous solutions. Herein, a decoupled design is proposed to optimize a full utilization of perchlorate ion intercalation in graphite cathode by pH adjustment. Benefiting from the decoupled design, high Coulombic efficiency is obtained by decelerating the kinetic of OER in acidic media. The decoupled Zn‐graphite battery exhibits a wide potential window of 2.01 V, as well as an attractive energy density of 231 Wh kg−1. In addition, a Zn‐graphite battery with SO42−${\mathrm{SO}}_4^{2 - }$ insertion is assembled, which demonstrates the capability of the proposed decoupled strategy to integrate novel electrode chemistries for high‐performance aqueous Zn‐based energy storage systems. [ABSTRACT FROM AUTHOR]

Zinc-based aqueous dual-ion batteries (ADIBs) with halogen-graphite intercalation compound positive electrodes are among the most competitive candidates for next-generation electrochemical energy storage systems. However, most of the electrolytes employed have been gel-like electrolytes; hence, a fundamental understanding of the halogen storage process using fluid hydrates will be essential for constructing efficient Zn-based ADIBs. Herein, the halogen storage mechanism on a graphite electrode from fluid ZnCl2/ZnBr2 hydrates is studied by experimental and computational methods. The results indicate that the halogen storage mechanism is a competition between conversion and intercalation. Moreover, the macroscopic electrode reaction is determined by both the ion-pair solvation state at the graphite–electrolyte interface and the subsequent reactant supply is influenced by the electrode reaction rate. [ABSTRACT FROM AUTHOR]

Alkali metal (AM) intercalation between graphene layers holds promise for electronic manipulation and energy storage, yet the underlying mechanism remains challenging to fully comprehend despite extensive research. In this study, we employ low-voltage scanning transmission electron microscopy (LV-STEM) to visualize the atomic structure of intercalated AMs (potassium, rubidium, and cesium) in bilayer graphene (BLG). Our findings reveal that the intercalated AMs adopt bilayer structures with hcp stacking, and specifically a C6M2C6 composition. These structures closely resemble the bilayer form of fcc (111) structure observed in AMs under high-pressure conditions. A negative charge transferred from bilayer AMs to graphene layers of approximately 1~1.5×1014 e−/cm−2 was determined by electron energy loss spectroscopy (EELS), Raman, and electrical transport. The bilayer AM is stable in BLG and graphite superficial layers but absent in the graphite interior, primarily dominated by single-layer AM intercalation. This hints at enhancing AM intercalation capacity by thinning the graphite material. Here, the authors report a study of the structural properties of intercalated alkali metals in bilayer graphene and graphite via low-voltage scanning transmission electron microscopy, providing mechanistic insights for the development of energy storage applications. [ABSTRACT FROM AUTHOR]

The temperature dependences of the transverse resistivity for acceptor intercalation compounds of different stages based on fine crystalline anisotropic graphite in the temperature range from 4.2 K up to 300 K are studied. The peculiarities of the transverse resistivity are analyzed in the terms of the Sugihara model, which assumes two mechanisms of conduction in the direction perpendicular to the graphite layers, namely the diffusive motion of the charge carriers along the graphite layers and the hopping conduction into the neighboring graphite layers. The possibility of the manifestation of quantum effects of the charge carriers' weak localization and interaction in a low temperature transverse resistance is evaluated. [ABSTRACT FROM AUTHOR]

Sulfur intercalation of a carbon rich (63×63)R30∘$(6\sqrt {3}\times 6\sqrt {3})R30\,^\circ$ reconstruction on silicon carbide, also known as buffer layer, is reported. In a two‐zone furnace a sulfur rich precursor is heated and the gaseous species is transported for intercalation by an argon flow to the sample. Successful intercalation can be confirmed by X‐ray photoelectron spectroscopy and low‐energy electron diffraction. Angle‐resolved photoelectron spectroscopy reveals a p‐type doping of the intercalated samples. In some cases only partial intercalation appears with non‐intercalated sulfur on top of the remaining buffer layer areas. Further annealing of such samples leads to a migration of the non‐intercalated sulfur under the buffer layer areas, indicating that the sulfur bonded to the buffer layer constitutes a transition state. [ABSTRACT FROM AUTHOR]

Graphene has gained significant attention since its discovery in 2004, and the modification of few-layer graphene provides a platform to tailor its physical and electronic properties. In this study, we employed unrestricted density functional theory (DFT) with the PBE+U functional to investigate the electronic and magnetic properties of FeCl3-intercalated bilayer graphene (BLG). Both in BLG and stage-2 intercalated graphite, a distinct localization of electrons on a specific Fe atom is evident, gaining approximately 0.245 electrons evaluated with Bader analysis, while the holes are delocalized within the graphene layers. This results in p-doped graphene, characterized by a shift of the Dirac cone by 0.74 eV for BLG and 0.70 eV for stage-2 intercalated graphite. Ferromagnetic ordering is observed within the plane of FeCl3-intercalated BLG, whereas the FeCl3 layers exhibit antiferromagnetic coupling in stage-2 intercalated graphite. The ferromagnetic nature and electronic structure of the FeCl3-intercalated BLG is retained under pressure. [ABSTRACT FROM AUTHOR]

The graphite intercalation compounds have attracted wide interest due to the superconductivity. In this work, the thermal transport in bilayer graphene intercalated with Ca atoms (C6CaC6) at room temperature is studied by using non-equilibrium molecular dynamics simulations. Our simulation results show that the in-plane lattice thermal conductivity (κ L) of C6CaC6 is significantly lower than that of the bilayer graphene. The detailed phonon mode analysis reveals that the reduction of κ L is because of the mode hybridization and flatbands induced by the intercalated Ca atoms, leading to the decrease in phonon group velocity and the enhancement of phonon scattering. Unlike the role of van der Waals interactions in multilayer graphene and supported graphene, increasing coupling strength between intercalated Ca atoms and graphene brings an enhanced κ L in C6CaC6. The spectral phonon analysis uncovers that such anomalous phenomenon is caused by the redistribution of phonon scattering phase space originated from the shift of the flatbands. This study indicates that atom intercalation is an effective way to regulate the heat transport in two-dimensional materials. [ABSTRACT FROM AUTHOR]

Atmospheric plasma processing, which combines the efficacy of chemical processes and the safety of physical processes, has been used to modify the surface characteristics of graphite-based materials. In this work, two distinct plasma source gases, C4F8 and O2, with the addition of a rotary reactor were used. The effectiveness of modifying the basal plane of intercalated graphite nanoplatelets (GnP) was investigated with various analytical techniques and the visual observation of the dispersion of these plasma-treated GnP in solvents was also reported. It is shown that this low-temperature plasma processing technique can be used to successfully modify the GnP surface without significantly changing the intrinsic structure of the GnP, which is desirable in many applications. With the C4F8 plasma treatment, the immersion characteristics in solvents can be tuned and the functional groups present on the surface can be tailored to produce desired bonding environments. This surface chemistry tunability will provide the needed functionalities in creating graphene-containing composite materials. [ABSTRACT FROM AUTHOR]

Graphite anodes experience co‐intercalation of K+ ions and solvent in ether‐based electrolytes, which enables ultrafast kinetics of potassium‐ion storage. The potassium‐ion storage mechanisms of amorphous soft carbon (SC) and hard carbon (HC) anodes in ether‐based electrolytes are ambiguous. Herein, the co‐intercalation mechanisms of SC and HC in ether‐based electrolytes are elucidated. The solvated K+ intercalates with a solvation structure, which avoids the sluggish desolvation process. Thus, HC and SC anodes display excellent rate capabilities. Moreover, the SC anode forms ternary K‐graphite intercalation compounds during the potassiation process. It is also demonstrated that solvated K+ is not only stored in the spacing between graphene nanodomains but can also be stored in the closed pores of HC, enabling higher capacities than pure K+ intercalation in ester‐based electrolytes. Nevertheless, the co‐intercalation causes the large volume expansion of SC and HC, giving rise to irreversible structural damage and capacity decay of SC and HC. The strong interaction between K+ ions and ether molecules is the main reason for the co‐intercalation. A thick and organic‐rich solid electrolyte interphase film formed in ester‐based electrolytes can hinder the co‐intercalation in ether‐based electrolytes. [ABSTRACT FROM AUTHOR]

We present a Li-intercalated-CeO2 catalyst that exhibits outstanding activity for ammonia synthesis. The incorporation of Li significantly reduces the activation energy and suppresses hydrogen poisoning of the Ru co-catalysts. As a result, the lithium intercalation enables the catalyst to achieve ammonia production from N2 and H2 at substantially lower operating temperatures. [ABSTRACT FROM AUTHOR]

We present an analytical model of the charge density wave instability in graphene sheets within the intercalated graphite CaC6 compound. The instability yields the experimentally observed uniaxial charge stripes of periodically modulated electron density, coupled to the softest phonon mode of the superlattice consisting of the Ca atoms intercalated between graphene planes. The Fermi surface of the chemically doped graphene undergoes the novel type of instability driven by the mechanism that gains the condensation energy of the stripe state by the topological reconstruction of the Fermi surface. This mechanism appears to be entirely different from the one based on the Fermi surface nesting, which has been considered a paradigm in the present literature concerning the onset of charge density waves. [ABSTRACT FROM AUTHOR]

Graphite electrodes are widely used in commercial metal‐ion batteries as anodes. Electrochemical impedance spectroscopy serves as one of the primary non‐destructive techniques to obtain key information about various batteries during their operation. However, interpretation of the impedance response of graphite electrodes in contact with common organic electrolytes can be complicated. It is especially challenging, particularly when utilizing the 2‐electrode configuration that is common in battery research. In this work, we elaborate on a physical impedance model capable of accurately describing the impedance spectra of a graphite|electrolyte|metallic Li system in a coin‐cell assembly during two initial charge/discharge cycles. We analyze the dependencies of the model parameters for graphite and metallic lithium as a function of the state of charge to verify the model. Additionally, we suggest that the double layer capacitance values obtained during specific intercalation stages could help to determine if the area‐normalized values align with the expected range. The data and the procedure necessary for calibration are provided. [ABSTRACT FROM AUTHOR]

Composites made of epoxy‐based systems are popular in many engineering applications because of their enhanced mechanical performance, fatigue properties, and other physical and thermal properties, but their low fracture toughness can limit their usefulness in high‐performance structural applications. This study aims to enhance the fracture properties of epoxy‐based composites by adding cost‐effective ball‐milled graphitic nanoparticles. Herein, dry ball milling for 15 and 48 h is done to produce ball‐milled graphite (BMG) nanoparticles. A significant reduction in particle size is achieved after 15 h of dry milling. Interestingly, a similar reduction in particle size is achieved for BMG (~258 nm) when wet ball milling for 3 h is performed. These BMGs were silanized (SBMG@3) and incorporated into the epoxy network. We found even at a higher loading level of SBMG@3, the resulting nanocomposites exhibited a significant improvement in fracture toughness (~2.47 MPa m1/2) and energy (~1.55 kJ/m2). This improvement was attributed to the upliftment of the in‐plane crack propagation resistance of the nanocomposites primarily offered by SBMG@3 due to coagulated interfacial interaction with the epoxy network that effectively hindered the propagation of the crack by providing numerous sites for energy dissipation, leading to improved fracture toughness. Our results demonstrate that SBMG@3 has great potential for improving the fracture toughness and energy of epoxy‐based composites, making them suitable for various industrial applications. Highlights: Synthesized cost‐effective 2D carbon nanofillers via high‐energy ball milling.To overcome the re‐agglomeration effect wet ball milling is performed.Transformation of natural graphite to BMG with sizes of ~258 nm.KIC and GIC improve to ~2.47 MPa m1/2 and 1.55 kJ/m2, respectively, for ECSB1.FS and FM of the epoxy nanocomposites enhanced by ~43.69% and ~51.64%. [ABSTRACT FROM AUTHOR]

[Display omitted] Reasonable construction of Li/Al-LDHs with interlayer anions is essential to improve the adsorption performance, especially for intercalating SO 4 2− anions and blocking Li+ desorption. Hence, anion exchange between Cl− and SO 4 2− in the interlayer of Li/Al-LDHs was designed and prepared to demonstrate the strong exchangeability of SO 4 2− for Cl− intercalated in the Li/Al-LDH interlayer. Intercalated SO 4 2− enlarged the interlayer spacing and significantly transformed the stacking structure of Li/Al-LDHs, resulting in fluctuating adsorption performance with changes in the intercalated SO 4 2− content at different ionic strengths. What is more, SO 4 2− repelled the intercalation of other anions, thus inhibiting Li+ adsorption, as verified by the negative correlation between adsorption performance and intercalated SO 4 2− content in high-ionic-concentration brines. Desorption experiments further revealed that enhanced electrostatic attraction between SO 4 2− and the Li/Al-LDH laminates hindered Li+ desorption. Additional Li+ in the laminates was essential for preserving the structural stability of Li/Al-LDHs with higher SO 4 2− contents. This work provides a new insight into the development of functional Li/Al-LDHs in ion adsorption and energy conversion applications. [ABSTRACT FROM AUTHOR]

Graphite is the state‐of‐the‐art anode active material in lithium‐ion batteries with high specific capacity and long cycling stability. Nevertheless, due to the growing market requirements especially for the automotive sector, many efforts are dedicated to improve the fast‐charging performance of the anode. Therefore, research focuses on different levels of the anode, for example, on material level to improve the kinetics of the lithium intercalation process or by optimization at the electrode level. For anode active material production, the spheroidization of natural and synthetic graphite is a very important step that affects particle characteristics and electrochemical behavior. Herein, natural and synthetic graphite materials are spheroidized by using a lab‐scale spheroidization process. The obtained samples are characterized by means of different analytical techniques to investigate the influence of the spheroidization conditions on selected graphite characteristics that directly influence the charging rate performance. Apart from particle morphology, surface‐related properties induced by the spheroidization process show correlation with the measured lithiation rate performance. [ABSTRACT FROM AUTHOR]

The intercalation of H into Pd-based nanocatalysts plays a crucial role in optimizing the catalytic performance by tailoring the structural and electronic properties. We herein present a comprehensive review about the recent progress of interstitial hydrogen atom modified Pd-based nanocatalysts for various energy-related electrocatalytic reactions. Before systematically manifesting the great potential of Pdbased hydrides for electrocatalytic applications, we have briefly illustrated the synthesis strategies and corresponding mechanisms for the Pd-based hydrides. This is followed by a comprehensive discussion about the fundamentals and functions of H intercalation in tailoring their physicochemical and electrochemical properties. Subsequently, we focus on the widespread application of Pd-based hydrides for electrocatalytic reactions, with the emphasis on the role of H intercalation played in determining electrocatalytic performance. Finally, the future direction and perspectives regarding the development of more efficient Pd-based hydrides are also manifested. [ABSTRACT FROM AUTHOR]

For Li‐ion and Na‐ion batteries, the intercalation behavior of graphite anodes is quite different. While Li‐ions intercalate, Na‐ions only co‐intercalate with solvent molecules from the electrolyte solution leading to ternary graphite intercalation compound (t‐GIC) formation along with an expansion of the graphite interlayer spacing to 1.2 nm. This large interlayer spacing represents a micropore with parallel slit geometry. Little is known about t‐GIC formation, but it is commonly believed that throughout the reaction the ion is accompanied by either a full or partial solvation shell. Here, it is elucidated for the first time, using two independent methods – mass measurements and electrochemical impedance spectroscopy – supplemented by operando microscopy, entropymetry and simulations, that the storage mechanism is far more complex. A new model for the electrochemical solvent co‐intercalation process is proposed: As soon as solvated ions enter, the graphite structure is flooded with free solvents, which are subsequently replaced by solvated ions. Close to full sodiation, few free solvents remain and structural rearrangement take place to reach the full storage capacity. Thus, t‐GICs represent a unique case of switchable microporous systems and hence appear as a bridge between ion storage in the bulk phase and in micropores, i.e., between batteries and supercapacitors. [ABSTRACT FROM AUTHOR]

Dual‐ion battery is a new type of battery in which both anions and cations participate in the energy storage process. However, this unique battery configuration imposes high requirements on the cathode, which typically presents a poor rate performance due to the sluggish diffusion dynamics and intercalation reaction kinetics of anions. Herein, we report petroleum coke‐based soft carbon as the cathode for dual‐ion batteries, exhibiting a superior rate performance with a specific capacity of 96 mAh g−1 at a rate of 2 C and 72 mAh g−1 remained even at 50 C. In situ XRD and Raman demonstrate that the anions can directly form lower‐stage graphite intercalation compounds during the charge process owing to the surface effect, skipping the long evolutionary process from higher to lower stage, thus significantly improving the rate performance. This study highlights the impact of the surface effect and provides a promising perspective for dual‐ion batteries. [ABSTRACT FROM AUTHOR]

Hybrid propulsion, consisting of solid fuel and liquid oxidizer, exhibits major advantage regarding safety, development costs, energetic performance, and controllability. Hence, it has been considered for space and other propulsion programs. One of the characteristic features of hybrid motors, that may be of major disadvantage, is their relatively low thrust due to the characteristic low regression rate of the typical polymeric solid fuels. This research group had revealed that a small fraction of an expandable graphite (EG) additive could double the burning rate and thrust of hybrid motors. EG is an intercalated form of graphite, elongating and swelling, getting a worm‐like string shape at elevated temperatures. In an earlier work it was hypothesized that enhanced heat transfer via conduction through the EG strings protruding from the hot surface, is a significant parameter increasing the burning rate. In the present investigation, thermal analysis revealed that the ignition temperature of polyester fuel containing 5 wt% of EG, is substantially lower than that of the pure polymer, which may promote higher burning rate as well. High‐speed photography of the surface of EG‐containing solid fuels as well as that of individual EG particles during controlled heating, demonstrated the dynamic behavior resulting in the formation of EG strings longer by an order of magnitude compared to the original particles. The different phenomena were related to the observation of enhanced burning rate. [ABSTRACT FROM AUTHOR]

Graphite is widely used as the negative electrode for alkali-metal ion secondary batteries because of its ability to accommodate various ions between its graphene layers resulting in the formation of graphite intercalation compounds (GICs). In this study, we investigated the intercalation of Cs+ ions into graphite using an ionic liquid (IL)-based electrolyte, Cs[FTA]–[C4C1pyrr][FTA] (FTA = (fluorosulfonyl)(trifluoromethylsulfonyl)amide, C4C1pyrr = N-butyl-N-methylpyrrolidinium). In this electrolyte, the graphite negative electrode imparted an initial reversible capacity of 180 mAh g−1 at 298 K. The formation of Cs-GICs was analyzed using an X-ray diffraction technique to reveal the formation of stage-1 CsC8. The formation potentials of various alkali metal GICs were also compared with respect to the potential of ferrocenium/ferrocene redox couple, revealing that these GICs particularly for stage-1 compounds form in a similar potential range with small differences of 0.2–0.3 V.

A thorough study of the chemical bonding between intercalated copper and host lattice TiCh2 (Ch = S, Te) was performed. In order to separate the contributions of the copper, titanium, and chalcogen states into the electronic structure of the valence band, photoelectron spectroscopy in nonresonant and resonant (Cu 3p-3d and Ti 2p-3d) excitation modes was used. It is shown that the ionicity of the chemical bond between copper and host lattice is decreased in the TiS2 → TiSe2 → TiTe2 row. In CuxTiS2, copper atoms form the chemical bond with TiCh2 host lattice, while in CuxTiTe2 directly with tellurium atoms. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of the types of interlayer anions on the adsorption performance of LDHs, herein, we synthesized three cobalt-aluminum layered double hydroxides (CoAl-LDHs) with different interlayer anions (NO3–/Cl–/CO32–). The experimental results demonstrate that the CoAl-LDH (Cl–) exhibited high adsorption capacity of 1372.1 mg/g at room temperature and the fastest adsorption rate on methyl orange (MO), mainly attributed to the excellent ion exchange capacity and high specific surface area and pore volume. Furthermore, the ion exchange driven by electrostatic interaction, hydrogen bonding, and surface complexation might be the main mechanisms for MO adsorption on CoAl-LDH (Cl–) and CoAl-LDH (NO3–). However, the MO adsorption on CoAl-LDH (CO32–) was strongly pH-dependent and the optimal pH value was about 3.5. Additionally, the supramolecular structure of CoAl-LDHs-MO was formed through electrostatic interaction, hydrogen bonding, and surface complexation between the host hydroxide layers and the guest MO– after adsorption equilibrium. An in-depth understanding of the differences in the adsorption performance of three anion-intercalated CoAl-LDHs will provide opportunities for further improvement of the adsorption capacity and exhibit a bright future for the design and optimization of efficient nano-adsorbents shortly. [ABSTRACT FROM AUTHOR]

A high‐concentration electrolyte is favored in dual‐ion batteries (DIBs) due to the lower onset potential for anion intercalation, higher specific discharge capacity, and better oxidation stability. Inspired by the correlation between the high‐concentration electrolytes and localized high‐concentration electrolytes, it is suspected that it is not the salt concentration but the solution structure of the electrolyte that determines the intercalation behavior of anion into graphite cathode. To prove the viewpoint, a series of electrolytes are prepared by controlling the salt concentration or solution structure and the intercalation behavior of PF6−$PF_6^ - $ within the graphite cathode is investigated in Li||graphite and graphite||graphite cells. It is found that PF6−$PF_6^ - $ anions exhibit similar onset potentials and specific discharge capacities in the electrolytes with different salt concentrations but similar solution structures. This study provides a new perspective on designing promising electrolytes for DIBs, which can accelerate the further exploitation of high‐performance DIBs. [ABSTRACT FROM AUTHOR]

Blending of poly(levorotatory-lactic acid) (PLLA) and poly(dextrorotatory-lactic acid) (PDLA) produces the stereocomplex crystallites (PLA SC), which present higher melting temperature and mechanical properties than that of neat PLLA or PDLA. However, in the PLLA/PDLA blends with higher molecular weights, the phase separation occurs and the SC exhibits weak memory after melting, which lead to a small amount of SC together with a large amount of homochiral crystallites (HC) develop during crystallization from the melt. In this study, a small content of graphite oxide was blended with PLLA and PDLA to form ternary blends, and it was exciting to find that the formation of SC was enhanced gradually with the content of graphite oxide. The SC exclusively developed when 2 wt% graphite oxide was incorporated into the PLLA/PDLA, and the crystallinity with ∼50% was received even during fast cooling from the melt (−50 °C/min). The acceleration formation of SC was speculated due to the interaction between PLA molecular chains and the hydroxyl groups on the surface of graphite oxide and the obstruction of proliferation of graphite oxide. [ABSTRACT FROM AUTHOR]

The representative of natural layered clays, bentonite, was modified according to two routes and tested as a new catalyst for selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR). The natural acid-activated clay was ion-exchanged with Na+ or remained in H-form and pillared with metal oxides. In order to limit the number of synthesis steps, iron as an active phase was introduced simultaneously with Al2O3 during the intercalation procedure. Additionally, the samples were doped with 0.5 wt% of copper to promote low-temperature activity. It was found that the performed modifications resulted in disorganization of the ordered layered arrangement of bentonite. Nevertheless, acid activation and pillaring improved structural and textural parameters. The results of catalytic tests indicated that the samples containing Fe2O3 pillars promoted with Cu exhibited the highest NO conversion of 85% at 250 °C (H-Bent-AlFe-Cu) and 75% at 300 °C (Na-Bent-AlFe-Cu). What is important, activity of the protonated samples in the high-temperature region was noticeably affected by the side reaction of ammonia oxidation, correlated with the production of NO and resulting in N2O emission during the process comparing to Na-Bentonite catalysts. [ABSTRACT FROM AUTHOR]

We report on the synthesis of self-intercalated Nb1+xSe2 thin films by molecular beam epitaxy. Nb1+xSe2 is a metal-rich phase of NbSe2 where additional Nb atoms populate the van der Waals gap. The grown thin films are studied as a function of the Se to Nb beam equivalence pressure ratio (BEPR). X-ray photoelectron spectroscopy and x-ray diffraction indicate that BEPRs of 5:1 and greater result in the growth of the Nb1+xSe2 phase and that the amount of intercalation is inversely proportional to the Se to Nb BEPR. Electrical resistivity measurements also show an inverse relationship between BEPR and resistivity in the grown Nb1+xSe2 thin films. A second Nb-Se compound with a stoichiometry of ∼1:1 was synthesized using a Se to Nb BEPR of 2:1; in contrast to the Nb1+xSe2 thin films, this compound did not show evidence of a layered structure. [ABSTRACT FROM AUTHOR]