Solid electrolyte material, solid electrolyte layer, and all solid state battery

1. A solid electrolyte material comprising:

a composite oxide containing Li and Bi; and

at least one solid electrolyte having a garnet structure, a perovskite structure, and a LISICON structure,

wherein a content of the composite oxide is 0.5% by volume to less than 20% by volume.

2. The solid electrolyte material according to claim 1 , wherein the solid electrolyte has a garnet structure or a LISICON structure.

3. The solid electrolyte material according to claim 1 , wherein the solid electrolyte has a garnet structure.

4. The solid electrolyte material according to claim 3 , wherein the garnet structure is represented by a composition formula (Li [7-ax-(b-4)y] A X ) La 3 Zr 2-y B y O 12 , wherein, A is at least one element selected from the group consisting of Ga, Al, Mg, Zn, and Sc; B is at least one element selected from the group consisting of Nb, Ta, W, Te, Mo, and Bi; 0≤x≤0.5; 0≤y≤2.0; a is an average valence for A; and b is an average valence for B.

5. The solid electrolyte material according to claim 3 , wherein the garnet structure is (Li 6.4 Ga 0.05 Al 0.15 )La 3 Zr 2 O 12 , (Li 6.4 Al 0.2 )La 3 Zr 2 O 12 , (Li 6.4 Ga 0.15 Sc 0.05 )La 3 Zr 2 O 12 , Li 6.75 La 3 (Zr 1.75 Nb 0.25 )O 11 , (Li 6.45 Al 0.1 )La 3 (Zr 1.75 Nb 0.25 )O 12 , (Li 6.175 Al 0.1 )La 3 (Zr 1.475 Ta 0.105 Bi 0.42 )O 12 , or Li 6.6 La 3 (Zr 1.6 Ta 0.4 )O 12 .

6. The solid electrolyte material according to claim 1 , wherein the content of the composite oxide is 1.0% by volume to 10% by volume.

7. The solid electrolyte material according to claim 1 , wherein a molar ratio of Li to Bi in the composite oxide is 1.0 or more.

8. The solid electrolyte material according to claim 1 , wherein the solid electrolyte material further includes at least one of a NASICON-type solid electrolyte, a ramsdellite-type solid electrolyte, and Li-B alumina.

9. The solid electrolyte material according to claim 1 , wherein the Bi in the composite oxide is trivalent Bi or pentavalent Bi.

10. The solid electrolyte material according to claim 1 , wherein the composite oxide containing Li and Bi has a melting point of 800° C. or lower.

11. The solid electrolyte material according to claim 1 , wherein the composite oxide containing Li and Bi further contains at least one of B, Si, P, W, Mo, and Te.

12. The solid electrolyte material according to claim 1 , wherein the solid electrolyte material further includes at least one of a composite oxide composed of La and Zr, a composite oxide composed of Li and Zr, and a composite oxide composed of Li and Al.

13. A solid electrolyte layer comprising a fired product of the solid electrolyte material according to claim 1 .

14. An all solid state battery comprising:

a negative electrode;

a solid electrolyte layer according to claim 13 on the negative electrode; and

a positive electrode on the solid electrolyte layer.