COMPOSITE CATHODE ACTIVE MATERIAL, CATHODE AND LITHIUM BATTERY EACH INCLUDING THE SAME, AND METHOD OF PREPARING COMPOSITE CATHODE ACTIVE MATERIAL

A composite cathode active material includes a secondary particle; and a coating on a surface of the secondary particle, wherein the secondary particle comprises a plurality of primary particles, and the plurality of primary particles include a lithium nickel transition metal oxide having a layered crystal structure; and a grain boundary between primary particles of the plurality of primary particles, the grain boundary including a lithium metal oxide having a crystal structure different from the lithium nickel transition metal oxide having a layered crystal structure, wherein the coating on the surface of the secondary particle includes a metal oxide including cobalt, and a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof