Sulfide-based solid electrolyte, method for producing the sulfide-based solid electrolyte, and method for producing all-solid-state battery

A method for producing a sulfide-based solid electrolyte comprising a sulfide glass-based material that contains at least one lithium halide compound selected from the group consisting of LiI, LiBr and LiCl,

• the method comprising immersing the sulfide glass-based material, which is at least one sulfide glass-based material selected from the group consisting of a sulfide glass and a glass ceramic, in an organic solvent having a solubility parameter of 7.0 or more and 8.8 or less, for 1 hour to 100 hours, thereby forming the sulfide glass-based material into a porous sulfide glass-based material,
• wherein the organic solvent is at least one selected from the group consisting of butyl butyrate, diethyl ether, cyclohexane, toluene, chlorotoluene, hexyl acetate, n-pentane, and n-octane, and
• wherein, when the sulfide glass-based material is a sulfide glass, the method further comprises heating the sulfide glass at a temperature higher than a crystallization temperature (Tc) of the sulfide glass, which is a temperature observed by thermal analysis measurement, thereby obtaining a glass ceramic, and
• wherein a specific surface area of the porous sulfide glass-based material measured by the BET method, is from 10 m2/g to 35 m2/g.