Composite cathode active material, cathode and lithium battery including composite cathode active material and preparation method thereof

A composite cathode active material, a cathode and a lithium battery including the composite cathode active material, and a preparation method of the composite cathode active material are provided. The composite cathode active material includes a first core including a first lithium transition metal oxide; a second core including a second lithium transition metal oxide; and a shell along a surface of at least one of the first core or the second core, wherein the shell includes a first metal oxide represented by Formula MOand a carbonaceous material, wherein the first metal oxide is within a carbonaceous metal matrix, the first lithium transition metal oxide and the second lithium transition metal oxide have a different particle size from each other, and the second lithium transition metal oxide includes a primary particle having a particle size of about 1 μm or more.