METHOD FOR PRODUCING SULFIDE SOLID ELECTROLYTE

The present invention is able to provide a method for producing a sulfide solid electrolyte, which is characterized by comprising: a solution forming step 1 wherein an Li-P-S homogeneous solution is 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; a solution forming step 2 wherein an Li-Si-S homogeneous solution, which contains at least elemental lithium (Li), elemental silicon (Si) and elemental sulfur (S) in an organic solvent, is prepared; a solution mixing step wherein a homogeneous mixed solution is prepared by mixing the Li-P-S homogeneous solution and the Li-Si-S homogeneous solution with each other; a slurry forming step wherein a slurry is prepared by mixing the homogeneous mixed solution and Li2S with each other; a drying step wherein a precursor is obtained by removing the organic solvent from the slurry; and a heating step wherein a sulfide solid electrolyte is obtained by heating the precursor at 200-700°C.