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-nickel metal oxide particle having a form of a secondary particle in which a plurality of primary particles are aggregated therein. The lithium-nickel metal oxide particle includes a penetration region formed in an area extending from a surface to a point 70% or less of a radius of the particle in a direction to a center of the particle. The penetration region includes a tungsten compound at an interface between the primary particles. A relative standard deviation (RSD) value calculated from results of measuring a tungsten content from the surface of the secondary particle to a depth of 10 nm 10 times at different points using an X-ray Photoelectron Spectroscopy (XPS) is in a range from 10% to 40%.