Sulfide-based solid electrolyte for lithium ion battery
Provided is a solid electrolyte with which charge/discharge efficiency and cycle characteristics can be increased by reducing the electron conductivity of a compound which has a cubic crystal structure belonging to a space group F-43m, and is represented by Compositional Formula: Li 7-x PS 6-x Ha x (Ha is Cl or Br). Proposed is a sulfide-based solid electrolyte for a lithium ion battery, which includes a compound having a cubic crystal structure belonging to a space group F-43m, and being represented by Compositional Formula: Li 7-x PS 6-x Ha x (Ha is Cl or Br), in which x in the above Compositional Formula is 0.2 to 1.8, and the value of the lightness L* thereof in the L*a*b* color system is 60.0 or more.
1. A sulfide-based solid electrolyte for a lithium ion battery comprising a compound which has a cubic crystal structure belonging to a space group F-43m and is represented by Compositional Formula: Li 7-x PS 6-x Ha x (Ha is Cl or Br), wherein x in the above Compositional Formula represents 0.2 to 1.8, and a value of lightness L* in a L*a*b* color system is 60.0 or more.
2. The sulfide-based solid electrolyte for a lithium ion battery according to claim 1 , wherein a transport number of lithium ion is 90% or more.
3. The sulfide-based solid electrolyte for a lithium ion battery according to claim 1 , wherein when Ha is Cl in the above Compositional Formula, x represents 0.2 to 1.8.
4. The sulfide-based solid electrolyte for a lithium ion battery according to claim 1 , wherein when Ha is Br in the above Compositional Formula, x represents 0.2 to 1.2.
5. The sulfide-based solid electrolyte for a lithium ion battery according to claim 1 , wherein the sulfide-based solid electrolyte for a lithium ion battery can be obtained by mixing a lithium sulfide (Li 2 S) powder, a phosphorus sulfide (P 2 S 5 ) powder, and a lithium chloride (LiCl) powder or a lithium bromide (LiBr) powder, and firing the mixture thus obtained at 350 to 500° C. under an inert atmosphere or firing the mixture thus obtained at 350 to 650° C. under an atmosphere including a hydrogen sulfide gas.
6. A lithium ion battery comprising the solid electrolyte according to claim 1 .
7. A lithium ion battery comprising the solid electrolyte according to claim 1 and a negative electrode active material including a carbon.
8. The sulfide-based solid electrolyte for a lithium ion battery according to claim 2 , wherein when Ha is Cl in the above Compositional Formula, x represents 0.2 to 1.8.
9. The sulfide-based solid electrolyte for a lithium ion battery according to claim 2 , wherein when Ha is Br in the above Compositional Formula, x represents 0.2 to 1.2.
10. The sulfide-based solid electrolyte for a lithium ion battery according to claim 2 , wherein the sulfide-based solid electrolyte for a lithium ion battery can be obtained by mixing a lithium sulfide (Li 2 S) powder, a phosphorus sulfide (P 2 S 5 ) powder, and a lithium chloride (LiCl) powder or a lithium bromide (LiBr) powder, and firing the mixture thus obtained at 350 to 500° C. under an inert atmosphere or firing the mixture thus obtained at 350 to 650° C. under an atmosphere including a hydrogen sulfide gas.
11. The sulfide-based solid electrolyte for a lithium ion battery according to claim 3 , wherein the sulfide-based solid electrolyte for a lithium ion battery can be obtained by mixing a lithium sulfide (Li 2 S) powder, a phosphorus sulfide (P 2 S 5 ) powder, and a lithium chloride (LiCl) powder or a lithium bromide (LiBr) powder, and firing the mixture thus obtained at 350 to 500° C. under an inert atmosphere or firing the mixture thus obtained at 350 to 650° C. under an atmosphere including a hydrogen sulfide gas.
12. The sulfide-based solid electrolyte for a lithium ion battery according to claim 4 , wherein the sulfide-based solid electrolyte for a lithium ion battery can be obtained by mixing a lithium sulfide (Li 2 S) powder, a phosphorus sulfide (P 2 S 5 ) powder, and a lithium chloride (LiCl) powder or a lithium bromide (LiBr) powder, and firing the mixture thus obtained at 350 to 500° C. under an inert atmosphere or firing the mixture thus obtained at 350 to 650° C. under an atmosphere including a hydrogen sulfide gas.
13. A lithium ion battery comprising the solid electrolyte according to claim 2 .
14. A lithium ion battery comprising the solid electrolyte according to claim 3 .
15. A lithium ion battery comprising the solid electrolyte according to claim 4 .
16. A lithium ion battery comprising the solid electrolyte according to claim 5 .
17. A lithium ion battery comprising the solid electrolyte according to claim 2 and a negative electrode active material including a carbon.
18. A lithium ion battery comprising the solid electrolyte according to claim 3 and a negative electrode active material including a carbon.
19. A lithium ion battery comprising the solid electrolyte according to claim 4 and a negative electrode active material including a carbon.
20. A lithium ion battery comprising the solid electrolyte according to claim 5 and a negative electrode active material including a carbon.