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Yellow needles-like single crystals of Li4P2S6 were obtained serendipitously during the preparation of Li7P3S10O. The twinned crystal structure of Li4P2S6 was determined from single-crystal X-ray diffraction data [wR(F2) = 0.069, 716 reflections, 40 variables]. Li4P2S6 crystallizes in the trigonal system, space group P 3 ‾ m 1 (N° 164), a = 10.5042(8) Å, c = 6.5837(6) Å, V = 629.11(9) Å3 and Z = 2. The lithium octahedra form a [Li4S6]8− honeycomb-like structure within which diphosphate units are located. The comparison of our crystal structure to those of P63/mcm-, P 3 ‾ 1 m -, and P321-Li4P2S6 demonstrated group-subgroup relationships and associated the disorder or order of the phosphorus atoms within the identical [Li4S6]8− 3d-frameworks to the choice of the unit cell (the subcell with a ∼ 6.07 Å vs. the supercell with a ∼ 10.5 Å). [ABSTRACT FROM AUTHOR]

Li3PS4 is the most typical solid electrolyte for all-solid-state lithium batteries. However, to date, there are few reports on Li3PS4 solid electrolyte synthesized using the solution process. Here, β-Li3PS4 solid electrolytes were prepared via liquid-phase synthesis by dissolving Li2S and P2S5 in ethylenediamine (EDA) to form a homogeneous solution of Li3PS4. Since EDA is a basic protonic solvent, it effectively suppressed the decomposition of Li3PS4. An intermediate phase consisting of Li3PS4 and EDA was formed as a precursor after drying the EDA solution at 200 °C under vacuum. After heat treatment at temperatures above 260 °C, β-Li3PS4 was crystallized from the precursor. The ionic conductivity of the prepared β-Li3PS4 was 5.0 × 10−5 S cm−1 at 25 °C and the activation energy for conduction was 35 kJ mol−1. The obtained EDA solution of Li3PS4 will be effective in forming electrolyte-electrode interfaces with the large contact areas in all-solid-state batteries. Highlights: β-Li3PS4 is prepared via liquid-phase synthesis using a ethylenediamine solution. Ethylenediamine effectively suppresses the decomposition of PS43−. The ionic conductivity of the prepared β-Li3PS4 is 5.0 × 10−5 S cm−1 at 25 °C. [ABSTRACT FROM AUTHOR]

Sulfide-based solid electrolytes (SEs) exhibiting high ionic conductivity are indispensable battery materials for next-generation all-solid-state batteries. However, sulfide-based SEs have a major drawback in their low chemical stability in air. When exposed to H2O or O2 gas, toxic H2S is generated, and their ionic conductivity considerably declines. However, their degradation mechanism caused by air exposure has not been understood yet. To clarify the degradation process, in this study, we developed a transmission electron microscope (TEM) system to evaluate the air stability of battery materials. Using a vacuum transfer double-tilt TEM holder with a gas-flow system, the in situ observation of the degradation process was conducted for a sulfide-based Li4SnS4 glass ceramic under an air-flow environment. Consequently, electron diffraction (ED) patterns and TEM images could clearly capture morphological changes and the amorphization process caused by air exposure. Moreover, based on the analysis of ED patterns, it is observed that Li4SnS4 is likely to decompose because of the reaction with H2O in air. Therefore, this airtight and air-flow TEM system should be effective in clarifying the process of the deterioration of sulfur-based SEs during exposure to air. [ABSTRACT FROM AUTHOR]

Composite graphite negative electrodes were prepared by mixing graphite particles and 75Li 2 S·25P 2 S 5 (mol%) glass particles with weight ratios of x :100 −  x ( x  = 50, 60 and 70). The cell with the x  = 50 electrode showed the highest reversible capacity of more than 250 mAh g −1 . Optical microscopy was conducted for each composite electrode after electrochemical lithiation to investigate reaction distributions by color changes of graphite particles. In the x  = 50 electrodes, almost all the graphite particles changed to gold color, suggesting that the graphite particles were fully lithiated. In situ optical microscopy was also carried out for the composite graphite electrode to monitor color changes of graphite particles directly during charge-discharge tests. [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]

Abstract: Amorphous thin film electrolytes in the system Li4SiO4–Li3PO4 were prepared by pulsed laser deposition (PLD). The ionic conductivity of the amorphous film at the composition 50Li4SiO4·50Li3PO4 (mol%) was 1.6×10−6 Scm−1 at room temperature which is higher than the conductivities of Li3PO4 and Li4SiO4 films. The 50Li4SiO4·50Li3PO4 film was coated on LiCoO2 active material particles by PLD. All-solid-state lithium secondary batteries using the coated LiCoO2 electrode and the Li2S–P2S5 solid electrolyte were fabricated. The PLD coating of oxide film with high conductivity on LiCoO2 was effective in decreasing the electrode/electrolyte interfacial resistance and developing power density of the all-solid-state cells. [Copyright &y& Elsevier]

Abstract: All-solid-state lithium secondary batteries using LiCoO2 particles coated with amorphous Li2O–TiO2 films as an active material and Li2S–P2S5 glass-ceramics as a solid electrolyte were fabricated; the electrochemical performance of the batteries was investigated. The interfacial resistance between LiCoO2 and solid electrolyte was decreased by the coating of Li2O–TiO2 films on LiCoO2 particles. The rate capability of the batteries using the LiCoO2 coated with Li2Ti2O5 (Li2O·2TiO2) film was improved because of the decrease of the interfacial resistance of the batteries. The cycle performance of the all-solid-state batteries under a high cutoff voltage of 4.6V vs. Li was highly improved by using LiCoO2 coated with Li2Ti2O5 film. The oxide coatings are effective in suppressing the resistance increase between LiCoO2 and the solid electrolyte during cycling. The battery with the LiCoO2 coated with Li2Ti2O5 film showed a large initial discharge capacity of 130mAh/g and good capacity retention without resistance increase after 50 cycles at the current density of 0.13mA/cm2. [Copyright &y& Elsevier]

Abstract: All-solid-state lithium secondary batteries using LiCoO2 active materials coated with Li2SiO3 and SiO2 oxide films and Li2S–P2S5 solid electrolytes were fabricated and their electrochemical performance was investigated. The electrochemical performace of the all-solid-state cells at a high voltage region was highly improved by using oxide-coated LiCoO2. The oxide coatings are effective in suppressing the formation of an interfacial resistance between LiCoO2 and the solid electrolyte at a high cutoff voltage of 4.6V (vs. Li). As a result, charge–discharge capacities and cycle performance at the cutoff voltage were improved. The cell with Li2SiO3-coated LiCoO2 showed a large initial discharge capacity of 130mAhg−1 and a good capacity retention of 110mAhg−1 after 50th cycles at the cutoff voltage of 4.6V (vs. Li). [Copyright &y& Elsevier]

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]

RT-NaMn 1/2 Sn 1/2 S 2 was prepared by mechanochemical synthesis from a mixture of Na 2 S, MnS, and SnS 2. The crystal structure was determined from X-ray powder diffraction data. The chemical composition was confirmed by energy dispersive X-ray spectroscopy, and the electrical conductivity was measured using electrochemical impedance spectroscopy. The RT-NaMn 1/2 Sn 1/2 S 2 sample crystallizes with rock salt-type structure, space group Fm 3 ‾ m , a = 5.4368(2) Å, V = 160.71(2) Å3, and Z = 2. This sample exhibits an irreversible phase transition. It transforms into a high temperature phase, HT-NaMn 1/2 Sn 1/2 S 2 which crystallizes with α-NaFeO 2 -type structure, space group R 3 ‾ m , a = 3.7523 (4) Å, c = 19.883 (2) Å, V = 242.44 (4) Å3, and Z = 3. The structure was determined from single crystal XRD data. The electrical conductivities of the RT- and HT-forms are 2.5 × 10−8 S cm−1 (E a = 0.58 eV) and 3.3 × 10−7 S cm−1 (E a = 0.42 eV) at 25 °C, respectively. [Display omitted] • The cubic NaMn 1/2 Sn 1/2 S 2 phase was prepared by mechanochemical synthesis route. • The rock salt structure of the NaMn 1/2 Sn 1/2 S 2 phase was solved from XRPD data. • Irreversible cubic to trigonal phase transition was observed at high temperature. • The trigonal NaMn 1/2 Sn 1/2 S 2 phase is crystallizes with the α-NaFeO 2 -type structure. • The ionic conductivity of the trigonal phase is higher than the cubic phase. [ABSTRACT FROM AUTHOR]

Yellow needles-like single crystals of Li4P2S6 were obtained serendipitously during the preparation of Li7P3S10O. The twinned crystal structure of Li4P2S6 was determined from single-crystal X-ray diffraction data [wR(F2) = 0.069, 716 reflections, 40 variables]. Li4P2S6 crystallizes in the trigonal system, space group P 3 ‾ m 1 (N° 164), a = 10.5042(8) Å, c = 6.5837(6) Å, V = 629.11(9) Å3 and Z = 2. The lithium octahedra form a [Li4S6]8− honeycomb-like structure within which diphosphate units are located. The comparison of our crystal structure to those of P63/mcm-, P 3 ‾ 1 m -, and P321-Li4P2S6 demonstrated group-subgroup relationships and associated the disorder or order of the phosphorus atoms within the identical [Li4S6]8− 3d-frameworks to the choice of the unit cell (the subcell with a ∼ 6.07 Å vs. the supercell with a ∼ 10.5 Å). [ABSTRACT FROM AUTHOR]

Transparent needles-like single crystals of Na 2 MgP 2 S 6 were obtained by self-flux synthesis route from Na 2 S, Mg, and P 2 S 5. The crystal structure of the new compound was determined from single-crystal X-ray diffraction data [ wR (F 2) = 0.066, 1088 reflections, 58 variables]. The chemical composition was confirmed by energy dispersive X-ray spectroscopy (EDX), and the ionic conductivity was measured using electrochemical impedance spectroscopy (EIS). Na 2 MgP 2 S 6 crystallizes in the orthorhombic system, space group Pbcn (N° 60), a = 7.3629 (3) Å, b = 21.5547 (8) Å , c = 6.2155 (3) Å, V = 986.43 (7) Å3 and Z = 4. The sulfur atoms form a distorted hexagonal close packing within which the sodium, magnesium, and P-P dimer units are octahedrally coordinated and form a honeycomb-like structure. Two of the three sodium atomic positions are partially occupied. Na 2 MgP 2 S 6 exhibits an ionic conductivity of 8.8×10−7 S cm−1 (E a = 0.48 eV) at 29.6 °C. [Display omitted] • The crystallographic data of thiohypodiphosphate compounds were reviewed. • The single crystals of Na 2 MgP 2 S 6 were obtained by self-flux synthesis route. • The unique crystal structure of Na 2 MgP 2 S 6 was solved from single crystal XRD. • The structure of Na 2 MgP 2 S 6 is isostructural to the Na 2 MnP 2 S 6 -type. • The electrical conductivity of Na 2 MgP 2 S 6 is 8.8×10−7 S cm−1 at 29.6 °C. [ABSTRACT FROM AUTHOR]

White opaque single crystals of Na 6 Ge 2 S 6 O were obtained serendipitously during the preparation of Na 4 GeS 4. Then, pure glass and ceramic Na 6 Ge 2 S 6 O samples were synthesized from Na 2 S, GeS 2 , and GeO 2 reagents. The crystal structure was determined from powder and single crystal X-ray diffraction data. The physical properties were characterized by TG-DTA, SEM-EDX, Raman spectroscopy and electrochemical impedance spectroscopy. Na 6 Ge 2 S 6 O crystallizes with a new type of structure in the non-centro-symmetric space group P 2 1 2 1 2 1 , a = 6.96882 (6) Å, b = 7.04159 (6) Å, c = 26.7069 (2) Å, V = 1310.55 (2) Å3 and Z = 4. The asymmetric unit is built up of six Na+ cations surrounding a bi-tetrahedral complex anion, [S 3 GeOGeS 3 ]6−, which adopts a staggered conformation. The strongly distorted sodium polyhedra share edges and/or faces. The electrical conductivities of Na 6 Ge 2 S 6 O glass and ceramic at 25 °C are 2.9 × 10−5 S cm−1 (E a = 0.47 eV) and 1.8 × 10−7 S cm−1 (E a = 0.43 eV), respectively. [Display omitted] • The ternary system Na 2 S-GeO 2 -GeS 2 was investigated by solid state synthesis. • Glass and ceramic forms of the new Na 6 Ge 2 S 6 O compound were prepared. • Single crystals of Na 6 Ge 2 S 6 O were isolated after melting the Na 4 GeS 4 composition. • The new crystal structure was solved from powder and single crystal XRD data. • The electrical conductivity of amorphous Na 6 Ge 2 S 6 O is 2.9 × 10−5 S cm−1 at 25 °C. [ABSTRACT FROM AUTHOR]

The Na 2 S-Na 4 GeS 4 section of the binary system Na 2 S-GeS 2 has been studied and the crystal structure of the Na 4 GeS 4 compound was determined from single-crystal X-Ray diffraction data. The physical properties of Na 4 GeS 4 were characterized by X-ray powder diffraction, TG/DTA, SEM-EDX, Raman spectroscopy and electrochemical impedance spectroscopy. Na 4 GeS 4 crystallizes with a new type of structure in the non-centro-symmetric space group Im , a = 10.9822(9) Å, b = 29.652(2) Å, c = 20.0391(16) Å, β = 105.77(1) (°), V = 6279.96(90) Å3 and Z = 30. The Na 4 GeS 4 asymmetric unit that contains 76 atoms is made up of 10 isolated GeS 4 tetrahedra. The 31 sodium atoms are located between these tetrahedra. The distorted NaS 6 octahedra, NaS 5 trigonal bipyramids, NaS 5 square pyramids and NaS 4 tetrahedra share corners, edges or faces. The electrical conductivity [2.7 × 10−5 S cm−1 (E a = 0.41 eV) at 25 °C] of the Na 4 GeS 4 glass phase, prepared by mechanochemical synthesis, is two orders of magnitude higher than that of the glass-ceramic phase, prepared by the combination of mechanochemical and solid-state synthesizes [9.8 × 10−8 (E a = 0.65 eV) at 25 °C]. [Display omitted] • The binary system Na 2 S-GeS 2 was reinvestigated by solid state synthesis. • Amorphous Na 4 GeS 4 was prepared by mechanochemical synthesis. • Single crystals of Na 4 GeS 4 were isolated after melting the Na 6 GeS 5 composition. • The unique crystal structure of Na 4 GeS 4 was solved from single crystal XRD. • The electrical conductivity of amorphous Na 4 GeS 4 is 2.7 × 10−5 S cm−1 at 25 °C. [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]

The ternary oxide glasses in the system of Li 3 BO 3 -Li 2 SO 4 -Li 2 CO 3 were prepared by mechanical milling. By heating the glasses to crystallize, the glass-ceramics were obtained. The 90Li 3 BO 3 ·7Li 2 SO 4 ·3Li 2 CO 3 (mol%) glass-ceramic electrolyte showed the conductivity of 1.0 × 10 − 5 S cm − 1 at room temperature, which was higher than that of the 90Li 3 BO 3 ·10Li 2 SO 4 glass-ceramic electrolyte. At the 33Li 3 BO 3 ·33Li 2 SO 4 ·33Li 2 CO 3 composition, a cold-pressed pellet at 720 MPa of the glass exhibited excellent formability with the relative density of 90%, which was comparable to that of sulfide glass electrolytes. By heating the glass, a metastable phase was precipitated and the glass-ceramic exhibited the conductivity of 1.8 × 10 − 6 S cm − 1 at room temperature. To obtain a denser pellet, hot-pressing at around its glass-transition temperature and consecutive crystallization were conducted. The hot-pressed pellet of the glass-ceramic was transparent and showed the conductivity of 2.3 × 10 − 6 S cm − 1 at room temperature. From the ultrasonic pulse-echo measurement, the bulk modulus of the glass was 44 GPa, which was lower than that of 68 GPa of the 90Li 3 BO 3 ·10Li 2 SO 4 glass. From the galvanostatic cycling test, the 33Li 3 BO 3 ·33Li 2 SO 4 ·33Li 2 CO 3 glass-ceramic electrolyte was kinetically stable against lithium metal negative electrode. The 33Li 3 BO 3 ·33Li 2 SO 4 ·33Li 2 CO 3 glass-ceramic electrolyte is therefore a promising material with both conductivity and ductility for the application to all-solid-state batteries. [ABSTRACT FROM AUTHOR]

Sulfide-based solid electrolytes have gained attention for application in solid-state lithium batteries, due to their high ionic conductivities, suitable mechanical properties, and wide electrochemical windows. However, the sulfide in these materials is very hygroscopic, and can react with traces of water, thus generating toxic H 2 S gas. This reduces the lithium-ion conductivity, which plays an important role in solid state batteries. On the contrary, it has also been found that the conductive performance of a sulfide solid electrolyte exposed to water can be partially recovered by a suitable heat treatment. In this study, multiple spectroscopic analyses using X-ray photoelectron spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, and diffuse reflectance infrared Fourier-transform spectroscopy were performed on an argyrodite-type sulfide solid electrolyte to elucidate the degradation mechanism under a small amount of moisture, as in a dry room, as well as the recovery mechanism of a degraded sample by vacuum heat treatment. We found that the degradation behavior of the PS 4 3− unit and the adsorption/desorption of water molecules on the surface of the electrolyte were correlated with the lithium-ion conductivity. [Display omitted] • Water durability of an argyrodite-type sulfide-based solid electrolyte in a low dew point air was investigated by using XPS, Raman, NMR, and DRIFTS. • The decomposed species and the adsorbed H 2 O were observed on the SE surface. • It was directly confirmed that the adsorbed H 2 O was desorbed by vacuum heating, and the conductivity recovered partially. [ABSTRACT FROM AUTHOR]

Liquid-phase synthesis for solid electrolytes has received considerable attention owing to its shape control, with the potential to produce particles easily on a large scale, and its low cost and energy consumption. However, solid electrolytes prepared through liquid-phase synthesis have been shown to have lower ionic conductivity than solid electrolytes prepared through the mechanical milling method. Recently, following various efforts, our group found that the crystallinity and remaining intermediate are the reasons for the low ionic conductivity of these materials. By using tetrahydrofuran (THF), we successfully improved the ionic conductivity of Li 3 PS 4 to 1.85 × 10−4 S cm−1 at 25 °C, higher than that afforded by ethyl propionate, which was reported to produce the highest ionic conductivity among the solvents used for liquid-phase synthesis. High-energy X-ray diffraction (XRD) measurements coupled with pair distribution function (PDF) analysis were employed to analyze the synthesized materials in order to determine why the ionic conductivity was higher than that of a sample prepared using ethyl propionate. The PDF analysis revealed that the crystallization of Li 3 PS 4 can be suppressed using THF, which has a lower boiling point than ethyl propionate. Moreover, it was revealed that the solvent could not be removed completely when the material has an amorphous structure, and thus, the ionic conductivity was lower than that of a material prepared using the solid-phase synthesis method. • By using tetrahydrofuran (THF) for liquid-phase synthesis, we prepared for Li3PS4 with relatively high ionic conductivity. • The Li 3 PS 4 structure was analyzed by high-energy X-ray diffraction coupled with pair distribution function (PDF) analysis. • The PDF analysis revealed that the crystallization of Li3PS4 can be suppressed using THF because of its low boiling point. • The THF could not be removed completely when the Li3PS4 has an amorphous structure, reducing the ionic conductivity. [ABSTRACT FROM AUTHOR]

Al-doped Li 7 La 3 Zr 2 O 12 (LLZ) sintered ceramics with two grain sizes were prepared to investigate the relationship between their microstructure and conducting properties. The X-ray diffraction patterns showed no difference in the peak shift and intensity between the two prepared LLZ ceramics, suggesting that their bulk conductivities were almost the same. Scanning electron microscopy and energy dispersive X-ray spectrometry were used to observe their microstructure. Neither of the ceramics had an obvious impurity phase along grain boundaries. One of LLZ (LLZ_LG) had a larger grain size of 5–20 μm and showed intergranular fracture. The other LLZ (LLZ_SG) had a smaller grain size of primarily <1 μm and showed intragranular fracture. LLZ_LG showed a total conductivity of 3.6 × 10−4 S cm−1 and an activation energy, E a , for conduction of 32 kJ mol−1, while LLZ_SG showed conductivity of 4.4 × 10−4 S cm−1 and E a of 26 kJ mol−1. It is noteworthy that the grain boundary composed of small grains showed lower grain boundary resistance than that composed of large grains. As a result, it is clarified that LLZ ceramics with higher ion-conductivity and lower E a can be prepared by suppressing grain growth. • Al-doped Li 7 La 3 Zr 2 O 12 (LLZ) sintered ceramics with two grain sizes are prepared. • LLZ_LG has a larger grain size of 5–20 μm and shows intergranular fracture. • LLZ_SG has a smaller grain size of <1 μm and shows intragranular fracture. • LLZ_SG shows higher total conductivity of 4.4 × 10−4 S cm−1 compared to LLZ_LG. • LLZ_SG shows lower E a of 26 kJ mol−1 compared to LLZ_LG. [ABSTRACT FROM AUTHOR]

Novel nitride glass electrolyte Li 3 BN 2 was prepared from Li 3 N and BN via a mechanochemical process using planetary ball milling. Raman and X-ray photoelectron spectroscopies revealed that the glass was composed of Li+ and BN 2 3− ions. The Li 3 BN 2 glass exhibited good ductility, and the powder-compressed pellet showed a relative density of 84%. The hot-pressed pellet of the Li 3 BN 2 glass showed a conductivity of 1.3 × 10−5 S cm−1 at 25 °C, which is much higher than that of oxide-based glass electrolytes such as Li 3 BO 3 glass and LiPON thin films. Moreover, Young's modulus of the Li 3 BN 2 glass was 51.1 GPa, which is an intermediate value between sulfides and oxides. The Li symmetric cell using the Li 3 BN 2 glass electrolyte was cycled stably at 100 °C without short-circuiting. Nitride glassy materials are promising electrolytes for all-solid-state batteries because of their high conductivity, good mechanical properties, and electrochemical stability. • Li 3 BN 2 glass electrolyte is prepared via a mechanochemical process. • The glass shows good ductility to be densified just by pressing at room temperature. • The glass electrolyte exhibits the conductivity of 1.3 × 10−5 S cm−1 at 25 °C. • The Li metal symmetric cell using the glass electrolyte is cycled stably at 100 °C. [ABSTRACT FROM AUTHOR]