Composite cathode active material, method of preparing the same, and cathode and lithium battery including the composite cathode active material

A composite cathode active material, comprising:

• a secondary particle comprising
• a plurality of primary particles comprising a lithium transition metal oxide having a layered crystal structure;
• and
• a coating layer disposed on a surface of the secondary particle and between primary particles of the plurality of primary particles,
• wherein the coating layer comprises a compound having a spinel crystal structure, and
• wherein the coating layer comprises a compound represented by Formula 1:
• LixCOaMebO4+δ Formula 1
• wherein, in Formula 1, Me is a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof, and
• wherein 1.0≤x≤1.1, 0<a<2, 0.4≤b≤1.6, 0<a+b≤2 and −1.5≤δ≤0.