NEW CATHODE ACTIVE MATERIAL

A cathode active material containing the second composite oxide is provided to improve high voltage characteristic of a lithium secondary battery, rate charging and discharging property and lifetime property. A method of manufacturing a cathode active material containing the second composite comprises (S1) a step for preparing the coating solution dispersed with an Al supply precursor in solvent; (S2) a step for dissolving the Al supply precursor in a solvent by heating the coating solution to 40~100 °C; (S3) a step for preparing the first lithium composite oxide remaining in the inside and on the surface of the first lithium composite oxide particles by using the excess of lithium supply precursor; (S4) a step for adding a solvent to the first lithium composite oxide and swelling it; (S5) a step for injecting the coating solution of (S2) step to the first lithium composite oxide and agitating the mixture; and (S6) a step for forming the second lithium composite oxide formed with a LiAlO2-containing film consecutively on the first lithium composite oxide particles by heating the material of (S5) step at 700°C~1000°C.