METHOD FOR PRODUCING SULFIDE SOLID ELECTROLYTE

A method for producing a sulfide solid electrolyte includes: forming an Li—P—S homogeneous solution prepared by mixing Li2S and P2S5 with each other in an organic solvent so that the Li2S/P2S5 molar ratio is from 0.7 to 1.5; forming an Li—Si—S homogeneous solution, which contains prepared containing at least elemental lithium (Li), elemental silicon (Si) and elemental sulfur (S) in an organic solvent; mixing a homogeneous mixed solution prepared by mixing the Li—P—S homogeneous solution and the Li—Si—S homogeneous solution with each other; forming a slurry prepared by mixing the homogeneous mixed solution and Li2S with each other; drying a precursor obtained by removing the organic solvent from the slurry; and a heating a sulfide solid electrolyte obtained by heating the precursor at 200-700° C.