All-solid-state secondary battery
An all-solid-state secondary battery including: a positive electrode layer; a negative electrode layer; and a solid electrolyte layer between the positive electrode layer and the negative electrode layer, wherein the positive electrode layer includes a sulfur-containing positive electrode active material, a halogen-containing sulfide solid electrolyte, and a conductive carbon material, and wherein the sulfur-containing positive electrode active material includes elemental sulfur and a transition metal disulfide.
1. An all-solid-state secondary battery, comprising:
a positive electrode layer;
a negative electrode layer; and
a solid electrolyte layer between the positive electrode layer and the negative electrode layer,
wherein the positive electrode layer comprises a sulfur-containing positive electrode active material, a halogen-containing sulfide solid electrolyte, and a conductive carbon material, and
wherein the sulfur-containing positive electrode active material comprises elemental sulfur and a transition metal disulfide and a weight ratio of the transition metal disulfide to the elemental sulfur is greater than 0 and less than 8.
2. The all-solid-state secondary battery of claim 1 , wherein the transition metal disulfide comprises iron disulfide.
3. The all-solid-state secondary battery of claim 1 , wherein the weight ratio of the transition metal disulfide to the elemental sulfur is greater than or equal to 0.5 and less than or equal to 2.
4. The all-solid-state secondary battery of claim 1 , wherein a content of the sulfur-containing positive electrode active material in the positive electrode layer is about 0.5 milligrams per square centimeter or more.
5. The all-solid-state secondary battery of claim 1 , wherein a content of the sulfur-containing positive electrode active material in the positive electrode layer is about 10 milligrams per square centimeter or less.
6. The all-solid-state secondary battery of claim 1 , wherein a content of the sulfur-containing positive electrode active material in the positive electrode layer is about 5 weight percent to about 70 weight percent, based on a total weight of the positive electrode layer.
7. The all-solid-state secondary battery of claim 1 , wherein a surface area of the conductive carbon material is about 1000 square meters per gram or more.
8. The all-solid-state secondary battery of claim 1 , wherein a surface area of the conductive carbon material is about 6000 square meters per gram or less.
9. The all-solid-state secondary battery of claim 1 , wherein the conductive carbon material comprises active carbon.
10. The all-solid-state secondary battery of claim 1 , wherein the halogen-containing sulfide solid electrolyte comprises a halide, and wherein the halide is of the formula LiX, wherein X is Cl, Br, I, or combination thereof.
11. The all-solid-state secondary battery of claim 1 , wherein a composition of the halogen-containing sulfide solid electrolyte is of the formula aLiX·(100-a)(0.75Li 2 S-0.25P 2 S 5 ), wherein 0<a<50 and X is Cl, Br, I, or a combination thereof.
12. The all-solid-state secondary battery of claim 1 , wherein a composition of the halogen-containing sulfide solid electrolyte is of the formula 35LiI·65(0.75Li 2 S.0.25P 2 S 5 ).
13. The all-solid-state secondary battery of claim 1 , wherein the positive electrode layer further comprises a sulfide solid electrolyte other than the halogen-containing sulfide solid electrolyte.
14. The all-solid-state secondary battery of claim 13 , wherein the sulfide solid electrolyte comprises Li 2 S—P 2 S 5 , Li 2 S—P 2 S 5 —LiX wherein X is a halogen element, Li 2 S—P 2 S 5 —Li 2 O, Li 2 S—SiS 2 , Li 2 S—SiS 2 —B 2 S 3 , Li 2 S—B 2 S 3 , Li 2 S—P 2 S 5 —Z m S n wherein m and n are each independently a positive integer and Z is Ge, Zn, Ga, or a combination thereof, Li 2 S—GeS 2 , Li 2 S—SiS 2 —Li 3 PO 4 , Li 2 S—SiS 2 —Li p MO q wherein p and q are each independently a positive integer, and M is P, Si, Ge, B, Al, Ga, In, or a combination thereof, or a combination comprising at least one of the foregoing.
15. The all-solid-state secondary battery of claim 13 , wherein the sulfide solid electrolyte comprises Li 3 PS 4 .
16. The all-solid-state secondary battery of claim 13 , wherein the sulfide solid electrolyte comprises Li 2 S—P 2 S 5 .
17. The all-solid-state secondary battery of claim 16 , wherein a molar ratio of Li 2 S to P 2 S 5 in the Li 2 S—P 2 S 5 is 50:50 to 90:10.
18. The all-solid-state secondary battery of claim 16 , wherein a composition of the sulfide solid electrolyte is 0.75Li 2 S.0.25P 2 S 5 .
19. The all-solid-state secondary battery of claim 1 , wherein the negative electrode layer is a lithium metal layer.
20. The all-solid-state secondary battery of claim 1 , wherein the weight ratio of the transition metal disulfide to the elemental sulfur is greater than or equal to 0.2 and less than or equal to 3.