Lithium secondary battery with high power
View Patent ↗The present invention provides a non-aqueous electrolyte-based high power lithium secondary battery having a long-term service life and superior safety at both room temperature and high temperature, even after repeated high-current charging and discharging, wherein the battery comprises a mixture of a particular lithium manganese-metal composite oxide (A) having a spinel structure and a particular lithium nickel-manganese-cobalt composite oxide (B) having a layered structure, as a cathode active material.
1. A cathode active material for a secondary battery, comprising a lithium manganese-metal composite oxide (A) having a spinel structure and represented by the following general formula 1, and a lithium nickel-manganese-cobalt composite oxide (B) having a layered structure and represented by the following general formula 2:
Li 1+x Mn 2−x−y M y O 4 (1)
Li 1−a Ni b Mn c Co 1−b−c O 2 (2)
wherein,
0<x<0.2;
0<y<0.1;
M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Ti, V, Zr and Zn;
−0.1≦a≦0.1;
0.3<b<0.5; and
0.3<c<0.5, wherein the content of the lithium manganese-metal composite oxide (A) is in the range of 80% to 95%, based on the total weight of the mixture, and the pH of the cathode active material is in the range of 8.9<pH≦10.2.
2. The cathode active material according to claim 1 , wherein the metal (M) is selected from the group consisting of Mg, Al, Co and Ni.
3. A lithium secondary battery comprising the cathode active material according to claim 2 .
4. A lithium secondary battery comprising the cathode active material according to claim 1 .
5. The lithium secondary battery according to claim 4 , wherein the battery is used as a high power, large capacity power source.