METHODE OF PREPARING SURFACE COATED CATHODE ACTIVE MATERIAL AND CATHODE ACTIVE MATERIAL PREPARED THEREBY

摘要

The present invention relates to a method of preparing a surface coated cathode active material, a surface coated cathode active material prepared thereby, and a lithium secondary battery including the surface coated cathode active material, wherein the method of preparing a surface coated cathode active material comprises a step of mixing a cathode active material with δ-Al_2O_3, and heat-treating the mixture to coat the surface of the cathode active material with Al_2O_3. According to an embodiment of the present invention, the method of preparing a surface coated cathode active material can form a surface coating layer having uniform distribution on the surface of the cathode active material by using δ-Al_2O_3, and can obtain surface coated active material having a high yield of 95% or more since the loss of the cathode active material can be minimized in the coating process. In addition, the surface coated active material prepared by the method includes the surface coating layer having the uniform distribution, thereby exhibiting stable lifetime properties at high temperatures and high voltage for a long period of time.