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The wet-chemical processability of sulfide solid electrolytes (SEs) provides intriguing opportunities for all-solid-state batteries. Thus far, sulfide SEs are wet-prepared either from solid precursors suspended in solvents (suspension synthesis) or from homogeneous solutions using SEs (solution process) with restricted composition spaces. Here, a universal solution synthesis method for preparing sulfide SEs from precursors, not only Li 2 S, P 2 S 5 , LiCl, and Na 2 S, but also metal sulfides (e.g., GeS 2 and SnS 2 ), fully dissolved in an alkahest: a mixture solvent of 1,2-ethylenediamine (EDA) and 1,2-ethanedithiol (EDT) (or ethanethiol). Raman spectroscopy and theoretical calculations reveal that the exceptional dissolving power of EDA-EDT toward GeS 2 is due to the nucleophilicity of the thiolate anions that is strong enough to dissociate the GeS bonds. Solution-synthesized Li 10 GeP 2 S 12 , Li 6 PS 5 Cl, and Na 11 Sn 2 PS 12 exhibit high ionic conductivities (0.74, 1.3, and 0.10 mS cm -1 at 30 °C, respectively), and their application for all-solid-state batteries is successfully demonstrated., (© 2022 Wiley-VCH GmbH.)

Developing high-performance all-solid-state batteries is contingent on finding solid electrolyte materials with high ionic conductivity and ductility. Here we report new halide-rich solid solution phases in the argyrodite Li 6 PS 5 Cl family, Li 6-x PS 5-x Cl 1+x , and combine electrochemical impedance spectroscopy, neutron diffraction, and 7 Li NMR MAS and PFG spectroscopy to show that increasing the Cl - /S 2- ratio has a systematic, and remarkable impact on Li-ion diffusivity in the lattice. The phase at the limit of the solid solution regime, Li 5.5 PS 4.5 Cl 1.5 , exhibits a cold-pressed conductivity of 9.4±0.1 mS cm -1 at 298 K (and 12.0±0.2 mS cm -1 on sintering)-almost four-fold greater than Li 6 PS 5 Cl under identical processing conditions and comparable to metastable superionic Li 7 P 3 S 11 . Weakened interactions between the mobile Li-ions and surrounding framework anions incurred by substitution of divalent S 2- for monovalent Cl - play a major role in enhancing Li + -ion diffusivity, along with increased site disorder and a higher lithium vacancy population., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Bulk-type all-solid-state lithium-ion batteries (ASLBs) for large-scale energy-storage applications have emerged as a promising alternative to conventional lithium-ion batteries (LIBs) owing to their superior safety. However, the electrochemical performance of bulk-type ASLBs is critically limited by the low ionic conductivity of solid electrolytes (SEs) and poor ionic contact between the active materials and SEs. Herein, highly conductive (0.14 mS cm -1 ) and dry-air-stable SEs (Li 4 SnS 4 ) are reported, which are prepared using a scalable aqueous-solution process. An active material (LiCoO 2 ) coated by solidified Li 4 SnS 4 from aqueous solutions results in a significant improvement in the electrochemical performance of ASLBs. Side-effects of the exposure of LiCoO 2 to aqueous solutions are minimized by using predissolved Li 4 SnS 4 solution., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

All-solid-state sodium-ion batteries that operate at room temperature are attractive candidates for use in large-scale energy storage systems. However, materials innovation in solid electrolytes is imperative to fulfill multiple requirements, including high conductivity, functional synthesis protocols for achieving intimate ionic contact with active materials, and air stability. A new, highly conductive (1.1 mS cm(-1) at 25 °C, Ea =0.20 eV) and dry air stable sodium superionic conductor, tetragonal Na3 SbS4 , is described. Importantly, Na3 SbS4 can be prepared by scalable solution processes using methanol or water, and it exhibits high conductivities of 0.1-0.3 mS cm(-1) . The solution-processed, highly conductive solidified Na3 SbS4 electrolyte coated on an active material (NaCrO2 ) demonstrates dramatically improved electrochemical performance in all-solid-state batteries., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new, highly conductive (4.1 × 10(-4) S cm(-1) at 30 °C), highly deformable, and dry-air-stable glass 0.4LiI-0.6Li4 SnS4 is prepared using a homogeneous methanol solution. The solution process enables the wetting of any exposed surface of the active materials with highly conductive solidified electrolytes (0.4LiI-0.6Li4 SnS4), resulting in considerable improvements in the electrochemical performance of these electrodes over conventional mixture electrodes., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)