Cathode active material and lithium secondary battery including the same, and method of manufacturing cathode active material
View Patent ↗Disclosed are a cathode active material and a lithium secondary battery including the same, and a method of manufacturing the cathode active material, the method including: (a) manufacturing a lithium metal oxide according to formula 1 below: Li 1+z Ni a Mn b Co 1−(a+b) O 2 (1) wherein 0≦z≦0.1, 0.1≦a≦0.8, 0.1≦b≦0.8 and a+b<1; (b) dry mixing the lithium metal oxide, and a precursor including zirconium and fluorine; and (c) changing the precursor including zirconium and fluorine into ZrO 2 and substituting some of oxygen (O) anions with F by heat-treatment after dry mixing of step (b), wherein the cathode active material is coated with ZrO 2 and F.
1. A method of manufacturing a cathode active material for secondary batteries, the method comprising:
manufacturing a lithium metal oxide according to formula 1 below:
Li 1+z Ni a Mn b CO 1−(a+b) O 2 (1)
wherein 0≦z≦0.1, 0.1≦a≦0.8, 0.1≦b≦0.8 and a+b<1;
dry mixing the lithium metal oxide and a precursor comprising zirconium and fluorine; and
changing the precursor comprising zirconium and fluorine into ZrO 2 and substituting some of oxygen (O) anions with F, by heat-treatment after the dry mixing,
wherein the cathode active material is coated with ZrO 2 and F, and in the dry mixing, an amount of a lithium transition metal oxide mixed with the precursor is controlled such that a total amount of ZrO 2 and F coated on the lithium transition metal oxide is 0.001 to 0.100 wt % based on the total weight of the cathode active material.
2. The method according to claim 1 , wherein the lithium metal oxide of Formula 1 is Li 1 Ni 1/3 Mn 1/3 Co 1/3 O 2 or LiNi 0.5 Mn 0.3 Co 0.2 O 2 .
3. The method according to claim 1 , wherein the precursor comprising zirconium and fluorine is ZrF 4 .
4. The method according to claim 1 , wherein an amount of the mixed lithium transition metal oxide is controlled such that a total amount of ZrO 2 and F is 0.001 to 0.010 wt % based on a total weight of the cathode active material.
5. The method according to claim 1 , wherein the dry mixing is carried out by high energy milling.
6. The method according to claim 1 , wherein the heat-treating is carried out at 400 to 1000° C. for 4 to 7 hours.
7. A cathode active material for secondary batteries coated with ZrO 2 and F manufactured using the method according to claim 1 .
8. The cathode active material according to claim 7 , wherein ZrO 2 and F are coated to a thickness of 0.01 to 0.10 μm.
9. The cathode active material according to claim 7 , wherein an area coated with ZrO 2 and F is 60 to 100% based on a surface area of the cathode active material.
10. A cathode mix comprising the cathode active material according to claim 7 .
11. A cathode for secondary batteries comprising the cathode mix according to claim 10 coated on a collector.
12. A lithium secondary battery comprising the cathode for the secondary batteries according to claim 11 .
13. The lithium secondary battery according to 13 , wherein the lithium secondary battery is a unit cell of a battery module as a power supply of a medium and large-scale device.
14. The lithium secondary battery according to 14 , wherein the medium and large-scale device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a system for storing power.