Solid-state battery
A solid-state battery comprising a positive electrode, a negative electrode, and a solid electrolyte membrane between the positive electrode and the negative electrode, the solid electrolyte membrane including a first solid electrolyte layer and a second solid electrolyte layer, is provided. The first solid electrolyte layer faces the positive electrode and includes a first sulfide-based solid electrolyte, and the second solid electrolyte layer includes a second sulfide-based solid electrolyte having an average particle diameter (D50) larger than an average particle diameter (D50) of the first sulfide-based solid electrolyte.
1 . A solid-state battery comprising:
a positive electrode;
a negative electrode; and
a solid electrolyte membrane between the positive electrode and the negative electrode,
wherein the solid electrolyte membrane comprises a first solid electrolyte layer and a second solid electrolyte layer,
wherein the first solid electrolyte layer faces the positive electrode and comprises a first sulfide-based solid electrolyte,
wherein the second solid electrolyte layer comprises a second sulfide-based solid electrolyte having an average particle diameter (D50) larger than an average particle diameter (D50) of the first sulfide-based solid electrolyte,
wherein a resistance of the second solid electrolyte layer is lower than a resistance of the first solid electrolyte layer.
2 . The solid-state battery according to claim 1 , wherein the average particle diameter (D50) of the second sulfide-based solid electrolyte is 2-7 times larger than the average particle diameter (D50) of the first sulfide-based solid electrolyte.
3 . The solid-state battery according to claim 1 , wherein the average particle diameter (D50) of the second sulfide-based solid electrolyte is 1 μm or more and 4 μm or less.
4 . The solid-state battery according to claim 1 , wherein the average particle diameter (D50) of the first sulfide-based solid electrolyte is 100 nm or more and 1,000 nm or less.
5 . The solid-state battery according to claim 1 , wherein a content of the second sulfide-based solid electrolyte is larger than a content of the first sulfide-based solid electrolyte.
6 . The solid-state battery according to claim 5 , wherein the content of the second sulfide-based solid electrolyte is 95 parts by weight or more based on 100 parts by weight of the second sulfide-based solid electrolyte layer, and
the content of the first sulfide-based solid electrolyte is 81-95 parts by weight or more based on 100 parts by weight of the first sulfide-based solid electrolyte layer.
7 . The solid-state battery according to claim 1 , wherein the first solid electrolyte layer has the same thickness as the second solid electrolyte layer.
8 . The solid-state battery according to claim 1 , wherein each of the first sulfide-based solid electrolyte and the second sulfide-based solid electrolyte contains sulfur(S) and has ion conductivity of a metal that belongs to Group 1 or Group 2 in the Periodic Table, and the first sulfide-based solid electrolyte and the second sulfide-based solid electrolyte are represented by the same chemical formula.
9 . The solid-state battery according to claim 8 , wherein each of the first sulfide-based solid electrolyte and the second sulfide-based solid electrolyte is any one selected from the group consisting of Li 2 S—P 2 S 5 , Li 2 S—LiI—P 2 S 5 , Li 2 S—P 2 S 5 —LiCl, Li 2 S—LiI—Li 2 O—P 2 S 5 , Li 2 S—LiBr—P 2 S 5 , Li 2 S—Li 2 O—P 2 S 5 , Li 2 S—Li 3 PO 4 —P 2 S 5 , Li 2 S—P 2 S 5 —P 2 O 5 , Li 2 S—P 2 S 5 —SiS 2 , Li 2 S—P 2 S 5 —SnS, Li 2 S—P 2 S 5 —Al 2 S 3 , Li 2 S—GeS 2 and Li 2 S—GeS 2 —ZnS, and
wherein the first sulfide-based solid electrolyte and the second sulfide-based solid electrolyte are represented by the same chemical formula.
10 . The solid-state battery according to claim 1 , wherein the first sulfide-based solid electrolyte has a particle diameter of 100-500 nm,
wherein the second sulfide-based solid electrolyte has a particle diameter of 2-4 μm,
wherein a content of the first sulfide-based solid electrolyte is 90 parts by weight or more based on 100 parts by weight of the first sulfide-based solid electrolyte layer, and
wherein a content of the second sulfide-based solid electrolyte is 95 parts by weight or more based on 100 parts by weight of the second sulfide-based solid electrolyte layer.
11 . The solid-state battery according to claim 1 , wherein the first solid electrolyte layer has an ion conductivity of 1×10 4 S/cm or more, and
the second solid electrolyte layer has an ion conductivity of 1×10 4 S/cm or more.
12 . The solid-state battery according to claim 1 , of which a time point where a short-circuit occurs is after 80 th cycle, when being charged at 0.1 C to 4.25 V in a constant current-constant voltage (CCCV) mode (0.05 C cut-off) and discharged at 0.1 C to 3 V cut-off in a constant current (CC) mode.