LITHIUM COBALT BASED COMPOSITE OXIDE, PREPARATION THEREOF, CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY USING THE SAME

摘要

PURPOSE: Provided is a lithium cobalt based composite oxide useful for a cathode active material for a lithium secondary battery. The composition shows excellent load characteristics and cycle life characteristics. CONSTITUTION: The lithium cobalt based composite oxide is formed by coating the surface of particles of lithium cobaltate represented by the formula of LixCoO2-a (wherein x ranges from 0.9 to 1.1, and a ranges from -0.1 to 0.1), with a sulfate salt. The lithium cobalt based composite oxide is prepared by the steps of: mixing a lithium compound with a cobalt compound and firing the mixture to obtain the lithium cobaltate represented by the above formula; and contacting the lithium cobaltate with an aqueous sulfate solution, drying the resultant product and causing the sulfate to be precipitated on the surface of the lithium cobaltate particles to obtain a lithium cobalt based composite oxide coated with the sulfate.