Method for producing sulfide solid electrolyte material
A sulfide solid electrolyte material having high Li ion conductivity can be obtained by providing a method for producing a sulfide solid electrolyte material that has peaks at 2θ=20.2° and 2θ=23.6° in an X ray diffraction measurement using a CuKα ray, the method including steps of: an amorphizing step of obtaining sulfide glass by amorphization of a raw material composition that contains at least Li 2 S, P 2 S 5 , LiI and LiBr and a heat treatment step of heating the sulfide glass at a temperature of 195° C. or higher.
1. A method for producing a sulfide solid electrolyte material that has peaks at 2θ=20.2° and 2θ=23.6° in an X ray diffraction measurement using a CuKα ray, the method comprising steps of:
an amorphizing step of obtaining sulfide glass by amorphization of a raw material composition that contains at least Li 2 S, P 2 S 5 , LiI and LiBr; and
a heat treatment step of heating the sulfide glass at a temperature of 195° C. or higher, wherein
a ratio of the LiBr relative to all the components in the raw material composition is equal to or more than 10 mol % and equal to or less than 20 mol %,
a ratio of the LiBr relative to the total of the LiI and the LiBr in the raw material composition:
LiBr/(LiI+LiBr)
is in the range of 15 mol % to 50 mol %, and
a ratio of the Li 2 S relative to the total of the Li 2 S and the P 2 S 5 in the raw material composition:
Li 2 S/(Li 2 S+P 2 S 5 )
is in the range of 70 mol % to 80 mol %.
2. The method for producing a sulfide solid electrolyte material according to claim 1 , wherein the sulfide solid electrolyte material has no peaks at 2θ=21.0° and 28.0°.
3. The method for producing a sulfide solid electrolyte material according to claim 1 , wherein
a ratio of the LiI relative to all the components in the raw material composition is more than 5 mol % and less than 15 mol %.