Sulfide solid electrolyte

1. A sulfide solid electrolyte comprising a crystallized glass represented by the following chemical formula (1):

75Li 2 S•(25- x )P 2 S 5 •x P 2 O 5   (1)

wherein:

0<x<25.

2. The sulfide solid electrolyte according to claim 1 , wherein the crystallized glass has a crystallinity of 50 to 100%.

3. The sulfide solid electrolyte according to claim 1 , having an ortho composition.

4. The sulfide solid electrolyte according to claim 1 , wherein the crystallized glass does not comprise a P 2 S 7 4− ion.

5. The sulfide solid electrolyte according to claim 1 , wherein 0<x≦20.

6. The sulfide solid electrolyte according to claim 1 , wherein 0<x≦15.

7. The sulfide solid electrolyte according to claim 1 , wherein 5≦x≦20.

8. The sulfide solid electrolyte according to claim 1 , wherein 5≦x≦15.

9. A method for producing a crystallized glass, comprising:

preparing a raw material composition comprising Li 2 S, P 2 S 5 and P 2 O 5 so that a content of Li 2 S is 75 mol % when a total content of Li 2 S, P 2 S 5 and P 2 O 5 is 100 mol %;

amorphizing the raw material composition; and

crystallizing a glass obtained by the amorphization by heating;

wherein the crystallized glass comprises a PS 4 3− ion but does not comprise a P 2 S 7 4− ion.

10. The method according to claim 9 , wherein the raw material composition is amorphized by mechanical milling.

11. A method for producing a crystallized glass, comprising:

preparing a raw material composition comprising Li 2 S, P 2 S 5 and P 2 O 5 so that a content of Li 2 S is 75 mol % when a total content of Li 2 S, P 2 S 5 and P 2 O 5 is 100 mol %;

amorphizing the raw material composition; and

crystallizing a glass obtained by the amorphization by heating.

12. The method according to claim 11 , wherein the raw material composition is amorphized by mechanical milling.