Aqueous solution synthesis of lithium-ion conductive tin-based sulphide electrolytes

To overcome the challenges associated with the toxicity of the majority of organic solvents for the liquid phase synthesis of solid electrolytes toward the human body and environment, we demonstrate the synthesis of tin-based sulphide electrolytes using water, which is the most environmentally friendly solvent. ortho-Thiostannate, i.e., Li4SnS4, was obtained from a mixture of Li2S, Sn, and S using aqueous solution synthesis. Furthermore, Li10SnP2S12, a superionic conductor, was obtained by mixing an aqueous solution of Li4SnS4 and tetrahydrofuran suspension of Li3PS4, which exhibited the highest ionic conductivity (5.9 x 10-3 S cm-1 at 25 degrees C) in liquid-phase synthesis. This study successfully demonstrates that water can be efficiently used to synthesize sulphide electrolytes instead of conventional organic solvents. To overcome the challenges associated with the toxicity of the majority of organic solvents for the liquid phase synthesis, we demonstrate the synthesis of tin-based sulfide electrolytes using water as the most environmentally friendly solvent.