All-solid secondary battery
An all-solid secondary battery includes a cathode layer; an anode layer; and a solid electrolyte layer disposed between the cathode layer and the anode layer. The cathode layer includes a cathode current collector and a cathode active material layer disposed on the cathode current collector, the anode layer includes an anode current collector and a first anode active material layer disposed on the anode current collector, the cathode active material layer includes a porous oxide-based composite solid electrolyte, and the solid electrolyte layer includes a sulfide-based solid electrolyte.
1. An all-solid lithium secondary battery comprising:
a cathode layer;
an anode layer; and
a solid electrolyte layer between the cathode layer and the anode layer,
wherein the cathode layer comprises a cathode current collector and a cathode active material layer on the cathode current collector,
wherein the anode layer comprises an anode current collector and a first anode active material layer on the anode current collector,
wherein the cathode active material layer comprises a porous oxide-based composite solid electrolyte and a cathode active material, and
wherein the solid electrolyte layer conducts lithium ion and comprises a sulfide-based solid electrolyte.
2. The all-solid secondary battery of claim 1 , wherein the porous oxide-based composite solid electrolyte comprises a porous oxide matrix, and an electrolyte in pores of the porous oxide matrix.
3. The all-solid secondary battery of claim 2 , wherein the porous oxide matrix comprises at least one selected from SiO 2 , Al 2 O 3 , ZrO 2 , TiO 2 , ZnO, SnO 2 , and CeO 2 .
4. The all-solid secondary battery of claim 2 , wherein the porous oxide matrix comprises ordered mesoporous pores.
5. The all-solid secondary battery of claim 2 , wherein the electrolyte comprises a lithium salt and a medium, and
wherein the medium comprises at least one selected from an organic solvent and an ionic liquid.
6. The all-solid secondary battery of claim 5 , wherein the lithium salt comprises at least one selected from LiN(SO 2 F) 2 (LiFSI), LiN(SO 2 CF 3 ) 2 (LiTFSI), LiSCN, LiN(CN) 2 , LiCIO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , LiC(CF 3 SO 2 ) 3 , LiN(SO 2 C 2 F 5 ) 2 , LiSbF 6 , LiPF 3 (CF 2 CF 3 ) 3 , LiPF 3 (CF 3 ) 3 , and LiB(C 2 O 4 ) 2 .
7. The all-solid secondary battery of claim 5 , wherein the organic solvent comprises at least one selected from N-methylacetamide, ethylene carbonate, propylene carbonate, dimethyl carbonate, fluoroethylene carbonate, diethyl carbonate, ethylmethyl carbonate, poly(ethylene glycol) dimethyl ether (PEGDME, polyglyme), tetra(ethylene glycol) dimethyl ether (TEGDME, tetraglyme), tri(ethylene glycol)dimethyl ether (triglyme), poly(ethylene glycol) dilaurate (PEGDL), poly(ethylene glycol) monoacrylate (PEGMA), poly(ethylene glycol) diacrylate (PEGDA), 3-dioxolane, 4,5-diethyl-1,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, 4-methyl-1,3-dioxolane, 4-ethyl-1,3-dioxolane, 2,2-dimethoxy-2-phenylacetophenone, 1,2-dimethoxyethane (DME), 1,2-diethoxyethane, tetrahydrofuran, gamma butyrolactone, 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, succinonitrile, adiponitrile, sulfolane, dimethylsulfone, ethylmethylsulfone, and diethylsulfone.
8. The all-solid secondary battery of claim 5 , wherein the ionic liquid is a compound comprising:
at least one cation selected from an ammonium-based cation, a pyrrolidinium-based cation, a pyridinium-based cation, a pyrimidinium-based cation, an imidazolium-based cation, a piperidinium-based cation, a pyrazolium-based cation, an oxazolium-based cation, a pyridazinium-based cation, a phosphonium-based cation, a sulfonium-based cation, a triazolium-based cation, and a mixture thereof; and
at least one anion selected from BF 4 − , PF 6 , AsF 6 , SbF 6 − , AlCl 4 − , HSO 4 , CIO 4 − , CH 3 SO 3 − , CF 3 CO 2 − , CI − , Br − , I − , BF 4 − , SO 4 − , CF 3 SO 3 − , (FSO 2 ) 2 N − , (C 2 F 5 SO 2 ) 2 N − (C 2 F 5 SO 2 )(CF 3 SO 2 )N − , and (CF 3 SO 2 ) 2 N − .
9. The all-solid secondary battery of claim 5 , wherein the porous oxide-based composite solid electrolyte comprises about 50 parts by weight to about 70 parts by weight of the porous oxide matrix, about 20 parts by weight to about 20 parts by weight of the lithium salt, and about 5 parts by weight to about 10 parts by weight of the medium based on 100 parts by weight of the porous oxide-based composite solid electrolyte.
10. The all-solid secondary battery of claim 1 , wherein an amount of the porous oxide-based composite solid electrolyte is about 1 wt % to about 30 wt % based on the total weight of the cathode active material layer.
11. The all-solid secondary battery of claim 1 , further comprising an inactive member on a peripheral part of the cathode current collector, surrounding one or more side surfaces of the cathode active material layer, and extending to a distal end of the cathode current collector.
12. The all-solid secondary battery of claim 1 , further comprising a carbon layer between the cathode current collector and the cathode active material layer.
13. The all-solid secondary battery of claim 1 , wherein the sulfide-based solid electrolyte comprises at least one selected from Li 2 S—P 2 S 5 , Li 2 S—P 2 S 5 —LiX (where X is a halogen), Li 2 S—P 2 S 5 —Li 2 O, Li 2 S—P 2 S 5 —Li 2 O—LiI, Li 2 S—SiS 2 , Li 2 S—SiS 2 —LiI, Li 2 S—SiS 2 —LiBr, Li 2 S—SiS 2 —LiCl 7 Li 2 S—SiS 2 —B 2 S 3 —LiI, Li 2 S—SiS 2 —P 2 S 5 —LiI, Li 2 S—B 2 S 3 , Li 2 S—P 2 S 5 —ZmSn (where m and n are each a positive number, and Z is one of Ge, Zn, or Ga), Li 2 S—GeS 2 , Li 2 S—SiS 2 —Li 3 PO 4 , and Li 2 S—SiS 2 —Li p MO q (where p and q are each a positive number, and M is one of P, Si, Ge, B, Al, Ga, or In).
14. The all-solid secondary battery of claim 1 , wherein the sulfide-based solid electrolyte comprises at least one selected from Li 7 P 3 S 11 , Li 7 PS 6 , Li 4 P 2 S 6 , Li 3 PS 6 , Li 3 PS 4 , and Li 2 P 2 S 6 .
15. The all-solid secondary battery of claim 1 , wherein the sulfide-based solid electrolyte comprises an argyrodite-type solid electrolyte represented by Formula 1:
Formula 1;
Li + 12-n-x A n+ X 2- 6-x Y − x , and
wherein, in Formula 1:
A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, or Ta,
X is S, Se, or Te,
Y is CI, Br, I, F, CN, OCN, SCN, or N 3 , 1≤n≤5, and
0≤c≤2.
16. The all-solid secondary battery of claim 15 , wherein the argyrodite-type solid electrolyte is at least one selected from Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0≤x≤2), and Li 7-x PS 6-x I x (where 0≤x≤2).
17. The all-solid secondary battery of claim 1 , wherein the first anode active material layer comprises an anode active material and a binder,
wherein the anode active material is in the form of particles, and
wherein an average particle diameter of the anode active material is about 4 μm or less.
18. The all-solid secondary battery of claim 17 , wherein the anode active material comprises at least one selected from a carbonaceous anode active material and a metal or metalloid anode active material, and
wherein the carbonaceous anode active material comprises at least one selected from amorphous carbon and crystalline carbon.
19. The all-solid secondary battery of claim 18 , wherein the metal or metalloid anode active material comprises at least one selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).
20. The all-solid secondary battery of claim 1 , further comprising a second anode active material layer between the anode current collector and the first anode active material layer,
wherein the second anode active material layer is a plated layer or a metal layer comprising lithium or a lithium alloy.