LITHIUM SULFIDE AND METHOD FOR PRODUCING SAME, AND METHOD FOR PRODUCING SULFIDE SOLID ELECTROLYTE
Lithium sulfide is provided having, in an X-ray diffraction pattern as measured using an X-ray diffraction apparatus using CuKα1 rays, a diffraction peak A at the position of 2θ=31.2°±1.0° and a diffraction peak B at the position of 2θ=23.0°±1.0°, and a value of I b to I a of from 0.012 to 0.045, where the I a is an intensity of the diffraction peak A and the I b is an intensity of the diffraction peak B. Furthermore, a value of I c to the I a is preferably 0.024 or less, where the I c is an intensity of a diffraction peak C that is at the position of 2θ=21.3°±1.2°.
1 . Lithium sulfide having, in an X-ray diffraction pattern as measured using an X-ray diffraction apparatus using CuKα1 rays,
a diffraction peak A at the position of 2θ=31.2°±1.0° and a diffraction peak
B at the position of 2θ=23.0°±1.0°, and
a value of I b to I a of from 0.012 to 0.045,
wherein the I a is an intensity of the diffraction peak A, and the I b is an intensity of the diffraction peak B.
2 . The lithium sulfide according to claim 1 ,
wherein, in an X-ray diffraction pattern as measured using an X-ray diffraction apparatus using CuKα1 rays, a value of I c to the I a is 0.024 or less,
wherein the I c is an intensity of a diffraction peak C at the position of 2θ=21.3°±1.2°.
3 . A method for producing the lithium sulfide according to claim 1 , comprising:
a step of firing lithium carbonate in an atmosphere containing sulfur gas and hydrogen gas,
wherein the sulfur gas is contained in the atmosphere in such a manner that a value of the number of moles of sulfur element with respect to the number of moles of lithium carbonate is from 8.0 to 24.0.
4 . A method for producing a sulfide solid electrolyte, comprising:
a step of mixing the lithium sulfide according to claim 1 with phosphorus pentasulfide and lithium halide to obtain a raw material composition; and
a step of firing the raw material composition in an atmosphere comprising an inert gas or an atmosphere comprising hydrogen sulfide gas.
5 . The production method according to claim 4 , wherein the raw material composition contains no elemental sulfur.