Surface-treated cathode active material and lithium secondary battery using the same
A surface-treated cathode active material useful for manufacturing a lithium secondary battery have excellent output characteristics by performing a double coating with metal oxide and an electron and ion conductive polymerized copolymer on a surface of a cathode active material for a lithium secondary battery to enhance electrochemical properties and thermal stability of the cathode active material.
1. A surface-treated cathode active material which is double-coated by primarily coating a metal oxide on a surface of a cathode active material, and secondarily coating a polymerized copolymer having both electron conductivity and ion conductivity thereby forming a double coating on the surface of the cathode active material,
wherein the polymerized copolymer is separated from the surface of the cathode active material and is a poly(3,4-ethylenedioxythiophene)-block-poly(ethylene glycol) (PEDOT-PEG).
2. The surface-treated cathode active material of claim 1 , wherein the cathode active material is selected from lithium transition metal oxides and sulfur compounds.
3. The surface-treated cathode active material of claim 1 , wherein the metal oxide is one or more selected from the group consisting of Al 2 O 3 , SiO 2 , TiO 2 , SnO 2 , CeO 2 , ZrO 2 , BaTiO 3 , and Y 2 O 3 .
4. The surface-treated cathode active material of claim 1 , wherein the metal oxide has an average particle diameter in a range of 1 to 100 nm.
5. The surface-treated cathode active material of claim 1 , wherein a total thickness of the double coating is in a range of 10 to 100 nm.
6. A lithium secondary battery comprising the surface-treated cathode active material of claim 1 .
7. The lithium secondary battery of claim 6 , wherein the battery is for a mobile electronic battery and an electric vehicle battery.
8. A lithium secondary battery comprising the surface-treated cathode active material of claim 2 .
9. A lithium secondary battery comprising the surface-treated cathode active material of claim 3 .
10. A lithium secondary battery comprising the surface-treated cathode active material of claim 4 .
11. A lithium secondary battery comprising the surface-treated cathode active material of claim 5 .