Synthesis of Li₁₀GeP₂S₁₂ Electrolyte Using Aqueous Solution

The development of a mass production process for sulfide electrolytes is crucial for the advancement of all-solid-state batteries. In this context, liquid-phase synthesis has gained attention as a practical and scalable approach for the synthesis of these materials. However, conventional liquid-phase synthesis typically employs organic solvents, which pose both environmental and safety concerns. In this study, a novel liquid-phase synthetic strategy is presented for the preparation of sulfide electrolytes using an aqueous solution, which eliminates the requirement for organic solvents. Consequently, a Li₁₀GeP₂S₁₂ electrolyte was successfully synthesized, and was demonstrated to exhibit an ionic conductivity of 1.6 × 10^-3 S cm^-1 at 25 °C in a powder compact. Additionally, an all-solid-state Li-In/LiNi_1/3Co_1/3Mn_1/3O₂ cell incorporating the developed electrolyte demonstrated stable and reversible cycle performances over 500 cycles. Overall, this work demonstrates the feasibility of using water as an environmentally friendly solvent for synthesizing high-performance sulfide electrolytes.