Method of producing sulfide solid electrolyte
Provided is a method of producing a sulfide solid electrolyte with which the capacity retention of an all-solid-state battery can be improved. The method of producing a sulfide solid electrolyte comprises synthesizing material for a sulfide solid electrolyte from raw material for an electrolyte; and after said synthesizing, heating the material for a sulfide solid electrolyte in a flow of a gas at a temperature of no less than a melting point of elemental sulfur, the gas being able to form a chemical bond with the elemental sulfur.
1. A method of producing a sulfide solid electrolyte, the method comprising:
synthesizing sulfide solid electrolyte material from an electrolyte raw material; and
after said synthesizing, heating the synthesized material in a flow of a H 2 S gas or a H 2 gas at a temperature that is lower than the formation temperature of a low Li-ion conductive phase but no less than a melting point of β-sulfur; wherein
the temperature, which is lower than the formation temperature of a low Li-ion conductive phase but no less than a melting point of β-sulfur, of the heating is within the range of 119.6° C. to 230° C.
2. The method of producing a sulfide solid electrolyte according to claim 1 , wherein said heating is in a flow of the H 2 S gas.
3. The method of producing a sulfide solid electrolyte according to claim 1 , further comprising:
washing a sulfide solid electrolyte with an organic solvent, the sulfide solid electrolyte being obtained after said heating in the flow of the H 2 S gas or the H 2 gas.
4. The method of producing a sulfide solid electrolyte according to claim 1 , wherein
the raw material for an electrolyte contains at least Li 2 S, and one or more sulfide(s) selected from P 2 S 3 , P 2 S 5 , SiS 2 , GeS 2 , B 2 S 3 and Al 2 S 3 ,
the method further comprising heat-treating the sulfides prior to said synthesizing.
5. The method of producing a sulfide solid electrolyte according to claim 4 , wherein the raw material for an electrolyte contains at least Li 2 S and P 2 S 5 .
6. The method of producing a sulfide solid electrolyte according to claim 1 , the method further comprising:
after said synthesizing and prior to said heating in the flow of the H 2 S gas or the H 2 gas, pulverizing the synthesized material.
7. The method of producing a sulfide solid electrolyte according to claim 1 , wherein
in said heating in the flow of the H 2 S gas or the H 2 gas, the synthesized material is heated at a temperature of no less than a crystallization temperature of the synthesized material, to obtain a sulfide solid electrolyte of glass ceramics.