Secondary battery with improved life characteristics
The present disclosure refers to a secondary battery which comprises a high-voltage cathode active material and a separator whose pores are not obstructed even though being used together with the high-voltage cathode active material, thereby preventing the obstruction of pores in the separator and the formation of a dendrite in the anode and eventually providing good battery life performance.
1. An electrode assembly, comprising:
a cathode;
an anode; and
a separator interposed between the cathode and the anode,
wherein the cathode comprises a cathode active material capable of being applied at a high voltage and represented by any one selected from the group consisting of following formulae (I) to (III), and mixtures thereof, and
wherein the separator comprises a porous substrate and a porous coating layer formed on only one surface of the porous substrate and comprising inorganic particles and an organic binder polymer, and has pores whose longest diameter ranges from 50 nm to 1 μm,
wherein the inorganic particles are present in an amount of 50 to 99 wt % based on 100 wt % of the total amount of the inorganic particles and the organic binder polymer,
wherein the porous coating layer is formed in a thickness of 0.5 to 20 μm, and
wherein the porous coating layer is disposed to be faced with the anode,
Li x [Ni a Co b Mn c ]O 2 (I)
(0.95≤x≤1.05, 0≤a, b, c≤1, a+b+c=1, and a and c are not simultaneously 0),
Li[Li x Ni a Co b Mn c ]O 2 (II)
(0.05≤x≤0.6, and x+a+b+c=1),
Li x [Ni a Co b Mn c ]O 2 (III)
(0.95≤x≤1.05, 0<a, b, c≤1, a+b+c=1, and 0.4<c<1).
2. An electrode assembly, comprising:
a cathode;
an anode;
and a separator interposed between the cathode and the anode,
wherein the cathode comprises a cathode active material capable of being applied at a high voltage and represented by any one selected from the group consisting of following formulae (I) to (III), and mixtures thereof, and
wherein the separator comprises a porous substrate and a porous coating layer formed on only one surface of the porous substrate and comprising inorganic particles and an organic binder polymer, and has pores whose longest diameter ranges from 10 nm to 5 μm,
wherein the inorganic particles are present in an amount of 50 to 99 wt % based on 100 wt % of the total amount of the inorganic particles and the organic binder polymer,
wherein the porous coating layer is formed in a thickness of 0.5 to 20 μm, and
wherein the porous coating layer is disposed to be faced with the anode,
wherein the inorganic particles have a size of 0.01 to 10 μm,
Li x [Ni a Co b Mn c ]O 2 (I)
(0.95≤x≤1.05, 0≤a, b, c≤1, a+b+c=1, and a and c are not simultaneously 0),
Li[Li x Ni a Co b Mn c ]O 2 (II)
(0.05≤x≤0.6, and x+a+b+c=1),
Li x [Ni a Co b Mn c ]O 2 (III)
(0.95≤x≤1.05, 0<a, b, c≤1, a+b+c=1, and 0.4<c<1).
3. An electrode assembly, comprising:
a cathode;
an anode; and
a separator interposed between the cathode and the anode,
wherein the cathode comprises a cathode active material capable of being applied at a high voltage and represented by any one selected from the group consisting of following formulae (I) to (III), and mixtures thereof, and
wherein the separator comprises a porous substrate and a porous coating layer formed on only one surface of the porous substrate and comprising inorganic particles and an organic binder polymer, and has pores whose longest diameter ranges from 10 nm to 5 μm,
wherein the inorganic particles are present in an amount of 50 to 99 wt % based on 100 wt % of the total amount of the inorganic particles and the organic binder polymer,
wherein the porous coating layer is formed in a thickness of 0.5 to 20 μm, and
wherein the porous coating layer is disposed to be faced with the anode,
wherein the porous substrate is a porous membrane obtained from a polyethylene resin, a polypropylene/polyethylene/polypropylene resin, or a polypropylene resin,
Li x [Ni a Co b Mn c ]O 2 (I)
(0.95≤x≤1.05, 0≤a, b, c≤1, a+b+c=1, and a and c are not simultaneously 0),
Li[Li x Ni a Co b Mn c ]O 2 (II)
(0.05≤x≤0.6, and x+a+b+c=1),
Li x [Ni a Co b Mn c ]O 2 (III)
(0.95≤x≤1.05, 0<a, b, c≤1, a+b+c=1, and 0.4<c<1).
4. The electrode assembly of claim 1 , wherein the cathode active material has an average diameter of 5 to 15 μm.
5. The electrode assembly of claim 1 , wherein the longest diameter of pores ranges from 50 to 500 nm.
6. The electrode assembly of claim 1 , wherein the porous coating layer is formed in a thickness of 3 to 6 μm.
7. The electrode assembly of claim 1 , wherein the inorganic particles have a dielectric constant of 5 or higher.
8. The electrode assembly of claim 1 , wherein the inorganic particles are selected from the group consisting of BaTiO 3 , Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), Pb(Mg 1/3 Nb 2/3 )O 3 —PbTiO 3 (PMN-PT), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC inorganic particles and a mixture thereof.
9. The electrode assembly of claim 1 , wherein the inorganic particles have a size of 0.01 to 10 μm.
10. The electrode assembly of claim 1 , wherein the organic binder polymer is selected from the group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer, polyimide, and a mixture thereof.
11. The electrode assembly of claim 1 , wherein the porous substrate is a porous membrane obtained from a polyethylene resin, a polypropylene/polyethylene/polypropylene resin, or a polypropylene resin.
12. The electrode assembly of claim 1 , wherein the porous substrate is a non-woven fabric.
13. The electrode assembly of claim 2 , wherein the inorganic particles have a dielectric constant of 5 or higher.
14. The electrode assembly of claim 2 , wherein the porous coating layer is formed in a thickness of 3 to 6 μm.
15. The electrode assembly of claim 3 , wherein the inorganic particles have a dielectric constant of 5 or higher.
16. The electrode assembly of claim 3 , wherein the porous coating layer is formed in a thickness of 3 to 6 μm.