METHOD FOR PREPARING CATHODE ACTIVE MATERIAL, CATHODE ACTIVE MATERIAL PREPARED BY THE SAME, AND LITHIUM SECONDARY BATTERIES COMPRISING THE SAME

摘要

The present invention relates to a method for preparing a positive electrode active material, comprising a step of mixing Li_(NH_4)_PO_4(+=3) to lithium metal composite oxide particles and treating the same by heat, wherein the a lithium metal phosphorus oxide is engraved and coated from surfaces of the lithium metal composite oxide particles to the inside by heat treatment, and to the positive electrode active material prepared by the method. According to the present invention, a lithium secondary battery using the positive electrode active material expresses high capacity due to the lithium metal phosphorus oxide having strong binding force with oxygen, and can highly improve lifespan properties since occurrence of oxygen gas is inhibited on surfaces of the positive electrode active material.