CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, PREPARATION METHOD THEREFOR AND LITHIUM SECONDARY BATTERY COMPRISING SAME

摘要

The present invention provides a cathode active material for a lithium secondary battery, comprising particles of a lithium cobalt oxide, wherein the particles of the lithium cobalt oxide comprises, on the particle surface and in a region corresponding to a distance of 0% or more and less than 100% from the particle surface with respect to a distance (r) from the surface to the center of the particle, a lithium defective lithium cobalt oxide, of which the mole ratio of Li/Co is less than 1 and a space group belongs to Fd-3m, and having a cubic crystalline structure. The cathode active material for a lithium secondary battery according to the present invention facilitates intercalation and deintercalation of lithium at the particle surface, thereby improving output characteristics and rate characteristics when applied to a battery. Consequently, excellent lifetime characteristics are exhibited and the amount of generated gas can be minimized even when the cathode active material is a large particle.