Sulfide-based solid electrolyte all solid secondary battery comprising sulfide-based solid electrolyte and preparation method thereof

As a sulfide-based solid electrolyte for an all-solid-state battery, presented are a sulfide-based solid electrolyte for an all-solid-state battery, an all-solid secondary battery containing the same, and a method for manufacturing a sulfide-based solid electrolyte, which contains a compound having an argyrodite-type crystal structure and represented by the following formula (1), which has an average particle diameter of 0.1 ㎛ to 10 ㎛, which has an ion conductivity of 0.01 mS/cm to 3 mS/cm at 25 ℃, in which the ratio (Ia/Ib) of the intensity (Ia) of the first peak at the diffraction angle 2θ=23°±0.5° and the intensity (Ib) of the second peak at the diffraction angle 2θ=25.5°±0.5° is greater than 0 and less than or equal to 1 in the XRD spectrum of the sulfide-based solid electrolyte. Li_aM1_xPS_yM2_zM3_w In the above formula, M1 is one or more metal elements other than Li selected from groups 1 to 15 of the periodic table, M2 is one or more elements selected from group 17 of the periodic table, and M3 is SO_n, 4