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Innovative rechargeable batteries that can effectively store renewable energy, such as solar and wind power, urgently need to be developed to reduce greenhouse gas emissions. All-solid-state batteries with inorganic solid electrolytes and electrodes are promising power sources for a wide range of applications because of their safety, long-cycle lives and versatile geometries. Rechargeable sodium batteries are more suitable than lithium-ion batteries, because they use abundant and ubiquitous sodium sources. Solid electrolytes are critical for realizing all-solid-state sodium batteries. Here we show that stabilization of a high-temperature phase by crystallization from the glassy state dramatically enhances the Na(+) ion conductivity. An ambient temperature conductivity of over 10(-4) S cm(-1) was obtained in a glass-ceramic electrolyte, in which a cubic Na(3)PS(4) crystal with superionic conductivity was first realized. All-solid-state sodium batteries, with a powder-compressed Na(3)PS(4) electrolyte, functioned as a rechargeable battery at room temperature.

Controlling Li ion transport in glasses at atomic and molecular levels is key to realizing all‐solid‐state batteries, a promising technology for electric vehicles. In this context, Li3PS4 glass, a promising solid electrolyte candidate, exhibits dynamic coupling between the Li+ cation mobility and the PS43− anion libration, which is commonly referred to as the paddlewheel effect. In addition, it exhibits a concerted cation diffusion effect (i.e., a cation–cation interaction), which is regarded as the essence of high Li ion transport. However, the correlation between the Li+ ions within the glass structure can only be vaguely determined, due to the limited experimental information that can be obtained. Here, this study reports that the Li ions present in glasses can be classified by evaluating their valence oscillations via Bader analysis to topologically analyze the chemical bonds. It is found that three types of Li ions are present in Li3PS4 glass, and that the more mobile Li ions (i.e., the Li3‐type ions) exhibit a characteristic correlation at relatively long distances of 4.0–5.0 Å. Furthermore, reverse Monte Carlo simulations combined with deep learning potentials that reproduce X‐ray, neutron, and electron diffraction pair distribution functions showed an increase in the number of Li3‐type ions for partially crystallized glass structures with improved Li ion transport properties. Our results show order within the disorder of the Li ion distribution in the glass by a topological analysis of their valences. Thus, considering the molecular vibrations in the glass during the evaluation of the Li ion valences is expected to lead to the development of new solid electrolytes. [ABSTRACT FROM AUTHOR]

Composite quasi-solid electrolytes composed of Li3PS4 (LPS) glass and a carboxylate ester were prepared via planetary ball milling, and the influence of the molecular structure of the carboxylate esters on their ion-conduction was investigated. The results revealed that filling the voids in the solid electrolyte with a bulky carboxylate ester, which hardly reacted with the LPS glass, effectively maintains the high ionic conductivity of the LPS glass even when the relative density of LPS decreases. The use of this composite quasi-solid electrolyte is an effective approach to maintain the ion-conduction in not only an electrolyte separator layer but also a composite electrode layer in an all-solid-state battery. [ABSTRACT FROM AUTHOR]

Highly safe all-solid-state batteries are constructed using oxide electrolytes because of their high chemical and electrochemical stabilities. Previously, we have developed various Li 3 BO 3 -based glass-ceramic electrolytes with high ductility and conductivity. In this study, we focus on the importance of electrode/electrolyte interfacial contacts in all-solid-state batteries. All-oxide solid-state cells (Li-In/LiNi 1/3 Mn 1/3 Co 1/3 O 2) with Li 3 BO 3 -based glass-ceramic electrolytes, are fabricated simply by pressing at room temperature. Furthermore, the effects of the ductility and ionic conductivity of glass-ceramic electrolytes on the charge-discharge properties of all-solid-state batteries are investigated. The 33Li 3 BO 3 ·33Li 2 SO 4 ·33Li 2 CO 3 (mol%) glass-ceramic electrolyte shows lower ionic conductivity and better ductility than the 90Li 3 BO 3 ·10Li 2 SO 4 electrolyte. The all-solid-state cells using these electrolytes operate as secondary batteries at 100 °C. However, better cycle performance is obtained with cells using the former electrolyte. Formation of well-contacted electrode/electrolyte interfaces when using highly ductile electrolytes leads to enhanced electrochemical performance of bulk-type all-solid-state batteries. • All-solid-state cells using Li 3 BO 3 -based glass-ceramic electrolytes are fabricated. • The cell with highly ductile electrolyte shows better charge-discharge performance. • Electrode-electrolyte interfacial formation is important for good cyclability. [ABSTRACT FROM AUTHOR]

(100 − x)(0.75Li2S·0.25P2S5)·xLiBH4 (0 ≤ x (mol%) ≤ 33) glass electrolytes were prepared from 75Li2S·25P2S5 (mol%) glass and LiBH4 crystal by a mechanical milling technique. The effects of the addition of LiBH4 on the structures and properties of the glass electrolytes were examined. The DSC curves of the prepared glasses with LiBH4 did not have the endothermic peak attributable to the phase transition of LiBH4 crystal. The Raman spectra of the glasses indicated that the glasses included PS4 3− and BH4 − ions. The conductivities of the glasses increased with increasing the LiBH4 content. The glass at the composition of x = 33 showed the highest lithium-ion conductivity of 1.6 × 10−3 S cm−1 at room temperature. The glass had a wide electrochemical window up to 5 V vs. Li+/Li. An all-solid-state Li/TiS2 cell using the glass as an electrolyte successfully operated as a secondary battery at 25 °C. [ABSTRACT FROM AUTHOR]

Highly lithium-ion conductive Li2S–P2S5 thin films were prepared using pulsed laser deposition at room temperature. The ambient Ar gas pressure during deposition strongly affected the thin films' chemical compositions and local structures. The chemical composition and the local structure of the 80Li2S·20P2S5 thin film prepared under 5 Pa showed good agreement with those of the highly lithium-ion conducting 80Li2S·20P2S5 glass powder prepared by mechanical milling. The ionic conductivity at 25°C and the activation energy for conduction of the as-deposited 80Li2S·20P2S5 thin films were, 7.9 × 10−5 S/cm and 43 kJ/mol, respectively. The ionic conductivity of the 80Li2S·20P2S5 thin film was increased to 2.8 × 10−4 S/cm through heat treatment. The highly lithium-ion conducting thin-films reported in this study are promising electrolytes for developing all-solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

Effects of modification of the electrode/electrolyte interface with Li2O-SiO2 thin films on impedance profiles and rate capabilities of all-solid-state ln/80Li2S·20P2S5 glass ceramic/LiCoO2 cells were investigated. Large resistance was observed at the LiCoO2—electrode/sulfide—electrolyte interface in all-solid-state cells. The interfacial resistance was decreased by 0.06 wt % oxide coatings on LiCoO2 the effective coatings were a lithium-ion conductive Li2SiO3 glassy film and an insulative SiO2 film. The Li2SiO3 coating film decreased the interfacial resistance more effectively when the coating amounts increased from 0.06 to 0.6 wt % (film thickness was ca. 10 nm). However, 0.6 wt % of SiO2 coating exhibited higher interfacial resistance than noncoating because the thick SiO2 coating film acted as a high-resistance layer. Temperature dependence of the interfacial resistance suggests that the resistance decrease was achieved mainly by an increase of pre-exponential factor rather than by a decrease of activation energy for ion conduction at the interface. At room temperature, all-solid-state cells with Li2SiO3-coated LiCoO2 were discharged even under the high current density, 6.4 mA cm-2. [ABSTRACT FROM AUTHOR]

Mechanical properties and ionic conductivities of solid electrolytes are important factors influencing the performance of all-solid-state batteries. This study investigates composite quasi-solid electrolytes composed of Li 2 S–P 2 S 5 glass and a phosphate ester, prepared via planetary ball milling, and the relative densities of the powder-compressed pellets, formed using the composite quasi-solid electrolytes. Dense pellets of the Li 2 S–P 2 S 5 glass electrolyte are obtained via addition of phosphate esters; the relative densities increase from 90.6% to 93.1%, without the ionic conductivities decreasing, upon addition of a small quantity of tris (2, 2, 2-trifluoroethyl) phosphate to the Li 3 PS 4 glass. The addition of small quantities of phosphate esters to sulfide solid electrolytes is effective in improving the formability of these solid electrolytes. • Quasi-solid electrolytes of Li 2 S-P 2 S 5 (LPS) glass and phosphate ester are prepared. • Relative density of the electrolytes increases by adding the ester to LPS glass. • Adding the ester increases formability and conductivity of the composites. [ABSTRACT FROM AUTHOR]

Abstract The use of Li metal anode is important for developing all-solid-state Li rechargeable batteries with high energy densities. In this study, all-solid-state Li symmetric cells using sulfide electrolytes in the Li 3 PS 4 -LiI system were fabricated to investigate the Li dissolution/deposition cycling performance. A cell using 54Li 3 PS 4 ·46LiI (mol%) glass electrolyte was cycled at a current density of 1.25 mA cm−2 for 3400 h at 100 °C without short-circuiting, and the highest areal capacity of 7.5 mAh cm−2 was achieved. Structural analyses of the interface between Li and solid electrolytes revealed that the reduction of electrolyte by the Li metal was suppressed by adding LiI to Li 3 PS 4 , and good interfacial contact was maintained even after prolonged cycling. The addition of LiI to Li 3 PS 4 glass improved the tolerance to reduction with Li metal, and enhanced the Li dissolution/deposition cycling performance. [ABSTRACT FROM AUTHOR]

All-solid-state sodium batteries are attracting attention as next-generation batteries, owing to their improved safety and abundance of sodium resources. To realize all-solid-state sodium batteries, solid electrolytes with high sodium-ion conductivities are required. In this study, Na 3 PS 4 electrolytes with partial substitution of P5+ with W6+ were investigated. The Na 3– x P 1– x W x S 4 sulfide-based solid electrolytes were prepared via a mechanochemical process and consecutive heat treatment. The Na 2.85 P 0.85 W 0.15 S 4 electrolyte with Na vacancies exhibited an ionic conductivity of 8.8 × 10−3 S cm−1 at 25 °C, which was higher than that of Na 3 PS 4 solid electrolyte. The all-solid-state batteries (Na-Sn/Na 2.85 P 0.85 W 0.15 S 4 /TiS 2) exhibited a reversible capacity of 140 mA h g−1 at a current density of 0.038 mA cm−2 and retained the capacity of 115 mAh g−1 for 40 cycles at 0.130 mA cm−2 at 25 °C. The Na 3– x P 1– x W x S 4 samples prepared via mechanochemistry are homogeneous electrolytes free of crystalline WS 2 impurities and are effective for application to all-solid-state sodium batteries. • Sulfide Na 3– x P 1– x W x S 4 electrolytes are prepared via a mechanochemical process. • Na 2.85 P 0.85 W 0.15 S 4 with Na vacancies shows a conductivity of 8.8 × 10−3 S cm−1. • All-solid-state cells exhibit a reversible capacity of 140 mAh g−1 of TiS 2 at 25 °C. [ABSTRACT FROM AUTHOR]

Sulfide-based lithium ionic conductors show high conductivity. Many studies have focused on improving conductivity and understanding their migration mechanisms. Argyrodite-type Li 6 PS 5 X (X = Cl, Br, I) electrolytes with P cations are among the main subjects of research regarding the substitution of anions and cations. In this study, argyrodite-type thioantimonate electrolytes were prepared to extend the compositions of argyrodite-type electrolytes and study their mechanisms of ion conduction. An argyrodite-type crystal precipitated in the composition of Li 6 SbS 5 I, but was not obtained in the composition of Li 6 SbS 5 X (X = Cl, Br). This could be explained by the difference in size between the SbS 4 tetrahedra and halide anions. Argyrodite-type Li 6 SbS 5 I displayed a conductivity of 2.1 × 10−6 S cm−1 at 25 °C, which was higher than that of Li 6 PS 5 I. Comparing these crystal structures, only the lattice parameters differed, and the site positions and occupancies were almost identical. However, the pathways limiting 3D migration were intra-cage jumps within Li 6 SbS 5 I and inter-cage jumps within Li 6 PS 5 I, based on their bond valence-based energy landscapes. The bottleneck sizes for ionic conduction in Li 6 SbS 5 I is better than that of Li 6 PS 5 I. This difference was due to the lattice parameters derived from the SbS 4 and PS 4 tetrahedra. This study reveals a strategy to predict the producibilities and increase the conductivities of argyrodite-type electrolytes. • Argyrodite-type Li 6 SbS 5 X (X = Cl, Br, I) electrolytes are prepared. • Only Li 6 SbS 5 I exhibits an argyrodite-type structure. • The sizes of the MS 4 tetrahedra are critical in forming the argyrodite structure. • Li 6 SbS 5 I displays a higher ionic conductivity than that of Li 6 PS 5 I. • The different sizes of the MS 4 tetrahedra affect the ion migration pathways. [ABSTRACT FROM AUTHOR]

All-solid-state sodium batteries with sulfide-based solid electrolytes are attracting attention as next-generation energy storage systems to replace Li-ion batteries, owing to their improved safety and the abundant sodium resources. Na 3 PS 4 -based materials, which have relatively high conductivities and favorable mechanical properties, make promising Na-ion solid electrolytes for realizing all-solid-state sodium batteries. However, it is essential to establish a further simple and effective protocol for manufacturing such solid electrolytes and composite electrodes. In this study, Na 3- x PS 4- x Cl x (x = 0, 0.0625) was prepared by a liquid-phase (suspension) process from Na 2 S, P 2 S 5 , and NaCl using 1,2-dimethoxyethane as a reaction media. Na 3 PS 4 heated at 400 °C and Na 2.9375 PS 3.9375 Cl 0.0625 heated at 480 °C exhibited Na-ion conductivities of 2.6 × 10−4 and 4.3 × 10−4 S cm−1 at 25 °C, respectively. A homogenous composite electrode was prepared with TiS 2 active material and Na 3 PS 4 solid electrolyte via the simple liquid-phase process, resulting in large contact areas between electrode and electrolyte particles. The electrode obtained by liquid-phase provided an all-solid-state cell with higher reversible capacity of 161 mAh g−1 than a conventional mechanically mixed electrode. Suspension syntheses of Na 3- x PS 4- x Cl x are useful for the simple production of solid electrolytes and are highly applicable to all-solid-state sodium batteries. • Na 3- x PS 4- x Cl x (x = 0, 0.0625) electrolytes are prepared using 1,2-dimethoxyethane. • Na 3 PS 4 shows a high sodium-ion conductivity of 2.6 × 10−4 S cm−1. • Na 2.9375 PS 3.9375 Cl 0.0625 exhibits a superior conductivity of 4.3 × 10−4 S cm−1. • A TiS 2 –Na 3 PS 4 composite electrode is obtained by a simple liquid-phase process. • An all-solid-state cell using the electrode shows a high capacity of 161 mAh g−1. [ABSTRACT FROM AUTHOR]

Abstract Li 3 SbS 4 glass was prepared by a mechanochemical process and a glass-ceramic was prepared by heating the glass above the crystallization temperature. The glass-ceramic had a crystal structure similar to that of γ-Li 3 PS 4. As indicated by the Raman spectra, both electrolytes contained an SbS 4 unit. The conductivity of the pelletized Li 3 SbS 4 glass was 1.5 × 10−6 S·cm−1 at 25 °C, which was higher than that of its glass-ceramic. The amount of H 2 S generated from Li 3 SbS 4 glass in humid air was considerably lower than that from the Li 3 PS 4 glass. Highlights • Li 3 SbS 4 glass electrolyte is prepared by a mechanochemical process. • The crystal structure of Li 3 SbS 4 precipitated in Li 3 SbS 4 glass-ceramic is revealed. • The glass exhibits the conductivity of 1.5 × 10−6 S cm−1 at 25 °C. • The conductivity of the glass-ceramic is lower than that of the glass. • The glass hardly generates any H 2 S gas even when exposed to humid air. [ABSTRACT FROM AUTHOR]

Na 3 PS 4 solid electrolytes were synthesized by liquid-phase reactions of Na 2 S and P 2 S 5 in 1,2-dimethoxyethane or diethyl ether. After stirring of the starting materials, white suspensions were obtained. The suspensions were dried at room temperature and heated at 270 °C under vacuum to obtain powders. The crystalline phases of the powders were cubic Na 3 PS 4 . The pelletized Na 3 PS 4 prepared using 1,2-dimethoxyethane or diethyl ether showed conductivities of 2.6 × 10 − 5 S cm − 5 or 1.8 × 10 − 5 S cm − 1 at 25 °C, respectively. [ABSTRACT FROM AUTHOR]

A new lithium-ion conducting oxide, hexagonal Li 4 GeO 4 , with a space group of P 6 3 /mmc , was prepared by mechanochemical treatment and subsequent heat treatment at 250 °C. The crystal structure was found in sulfide Li 4 SnS 4 , and this is the first study to report an oxide system. In addition, (100- x)Li 4 GeO 4 · x Li 2 MO 4 (M = S or W; x = 10, 20, 30, and 40 mol%) glass-ceramic electrolytes with the hexagonal phase were prepared by crystallization of their mother glasses. The formability of the electrolytes improved as the quantity of Li 2 SO 4 increased, and the 90Li 4 GeO 4 ·10Li 2 SO 4 glass-ceramic electrolyte showed the highest ionic conductivity of 2.9 × 10−6 S cm−1 at 25 °C. Compared with the experimental results, the bond valence sum (BVS) analysis results indicated that ionic conduction paths are easily connected along the c -axis in the hexagonal phase, suggesting that the relatively small lattices in the a - and b -axes are more advantageous for three-dimensional ionic conduction. • Li 4 GeO 4 -based glass electrolytes are prepared via a mechanochemical process. • The addition of Li 2 SO 4 improves the formability of the electrolytes. • A hexagonal metastable phase is formed by crystallization of Li 4 GeO 4 -based glasses. • The 90Li 4 GeO 4 ·10Li 2 SO 4 glass-ceramic has the highest conductivity of 2.9 × 10−6 S cm−1. [ABSTRACT FROM AUTHOR]