CATHODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

A cathode active material for a lithium secondary battery includes a lithium metal oxide particle containing nickel (Ni) and cobalt (Co). The lithium metal oxide particle includes a concentration gradient region formed in at least one region between a center of the lithium metal oxide particle and a surface of the lithium metal oxide particle. A ratio of a concentration represented as an atomic percent of Co at the surface relative to a concentration represented as an atomic percent of Co at the center is 6.7 or more.