POSITIVE ACTIVE MATERIAL FOR RECHARGEABLE LITHIUM BATTERY, METHOD OF PREPARING THE SAME AND RECHARGEABLE LITHIUM BATTERY INCLUDING THE SAME

A positive active material for a rechargeable lithium battery includes a nickel-based lithium transition metal oxide including a secondary particle in which a plurality of primary particles are agglomerated, wherein the secondary particle includes a core and a surface layer surrounding the core, and the surface layer includes a plurality of primary particles and a nano-sized cobalt-based lithium transition metal oxide absorbed in the surface layer, between the primary particles.