Positive electrode material and battery

1. A positive electrode material comprising:

a positive electrode active material;

a cover layer that covers at least part of a surface of the positive electrode active material and that contains a first solid electrolyte material; and

a second solid electrolyte material that is a material different from the first solid electrolyte material,

wherein the first solid electrolyte material contains Li, M, and X and does not contain sulfur,

M represents Y and at least one element selected from the group consisting of semi-metal elements and metal elements other than Li and Y, and

X represents halogen elements including Cl.

2. The positive electrode material according to claim 1 ,

wherein the first solid electrolyte material is denoted by Composition formula (1) below,

Li α M β X γ   Formula (1)

and herein, each of α, β, and γ represents a value greater than 0.

3. The positive electrode material according to claim 2 ,

wherein 2.7≤α≤3, 1≤β≤1.1, and γ=6 are satisfied.

4. The positive electrode material according to claim 1 ,

wherein the second solid electrolyte material contains Li, M′, and X′,

M′ is at least one element selected from the group consisting of metal elements other than Li and semi-metal elements, and

X′ represents halogen elements including at least one element selected from the group consisting of Br and I.

5. The positive electrode material according to claim 4 , wherein the second solid electrolyte material is denoted by Composition formula (2) below,

Li α′ M′ β′ X′ β′   Formula (2)

and herein, each of α′, β′, and γ′ represents a value greater than 0.

6. The positive electrode material according to claim 4 ,

wherein X includes Cl and at least one element selected from the group consisting of Br and I, and

A<B is satisfied, and herein, a molar ratio of a total of Br and I included in X to X is denoted as A and a molar ratio of a total of Br and I included in X′ to X is denoted as B.

7. The positive electrode material according to claim 1 , wherein X does not include Br.

8. The positive electrode material according to claim 4 ,

wherein X and X′ include Br, and

C<D is satisfied, and herein, a molar ratio of Br included in X to X is denoted as C and the molar ratio of Br included in X′ to X is denoted as D.

9. The positive electrode material according to claim 4 , wherein M′ includes yttrium.

10. The positive electrode material according to claim 4 , wherein X′ includes Cl and at least one element selected from the group consisting of Br and I.

11. The positive electrode material according to claim 1 , wherein the second solid electrolyte material is a sulfide solid electrolyte.

12. The positive electrode material according to claim 11 ,

wherein the sulfide solid electrolyte contains lithium sulfide and phosphorus sulfide.

13. The positive electrode material according to claim 11 ,

wherein the sulfide solid electrolyte is Li 2 S—P 2 S 5 .

14. The positive electrode material according to claim 1 , wherein the positive electrode active material is lithium-nickel-cobalt manganese oxide.

15. The positive electrode material according to claim 1 , wherein the positive electrode active material and the second solid electrolyte material are separated from each other by the first solid electrolyte material and are not in direct contact with each other.

16. A battery comprising:

a positive electrode containing the positive electrode material according to claim 1 ;

a negative electrode; and

an electrolyte layer disposed between the positive electrode and the negative electrode.

17. The battery according to claim 16 ,

wherein the electrolyte layer contains the same material as the first solid electrolyte material or the second solid electrolyte material.

18. The battery according to claim 17 , wherein the electrolyte layer contains the same material as the first solid electrolyte material.

19. The battery according to claim 16 , wherein the electrolyte layer contains a halide solid electrolyte different from the first solid electrolyte material.

20. The battery according to claim 19 , wherein the electrolyte layer contains a halide solid electrolyte different from the first solid electrolyte material and the second solid electrolyte material.

21. The battery according to claim 16 , wherein the electrolyte layer contains a sulfide solid electrolyte.

22. The positive electrode material according to claim 4 , wherein M′ is Y and at least one element selected from the group consisting of semi-metal elements and metal elements other than Li and Y.

23. A positive electrode material comprising:

a positive electrode active material;

a cover layer that covers at least part of a surface of the positive electrode active material and that contains a first solid electrolyte material; and

a second solid electrolyte material that is a material different from the first solid electrolyte material,

wherein the first solid electrolyte material contains Li, M, and X and does not contain sulfur,

M represents at least one element selected from the group consisting of metal elements other than Li and semi-metal elements, and

X represents halogen elements including Cl and at least one element selected from the group consisting of Br and I.

24. A battery comprising:

a positive electrode containing the positive electrode material according to claim 23 ;

a negative electrode; and

an electrolyte layer disposed between the positive electrode and the negative electrode.