Rapid and Economic Synthesis of a Li₇PS₆ Solid Electrolyte from a Liquid Approach

Solid electrolytes are the key to realize future solid-state batteries that show the advantages of high energy density and intrinsic safety. However, most solid electrolytes require long time and energy-consuming synthesis conditions of either extended ball milling or high-temperature solid-state reactions, impeding practical applications of solid electrolytes for large-scale systems. Here, we report a new and rapid liquid-based synthetic method for preparing a high-purity Li₇PS₆ solid electrolyte through the stoichemical reaction of Li₃PS₄ and Li₂S. This method relies on facile and low-cost solution-based soft chemistry to complete chemical reaction in extensively short time (2 h). The prepared Li₇PS₆ solid electrolyte shows a high phase purity, an impressive ionic conductivity (0.11 mS cm^-1), and a reasonable electrochemical stability with a metallic lithium anode. Our results highlight the use of an economic and nontoxic solvent to quickly synthesize a Li₇PS₆ solid electrolyte, which would promote the development of solid-state batteries for next-generation energy storage systems.