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

A composite cathode active material comprising a plurality of secondary particles, the secondary particles comprising:

• a core comprising an aggregate of a plurality of primary particles;
• and
• a shell on the core, the shell comprising a second composition comprising at least two second metals,
• wherein the plurality of primary particles comprise a nickel-containing lithium transition metal oxide represented by Formula 4:
• LiaNibCocMndM3eO2 Formula 4
• wherein, in Formula 4, 0.9≤a≤1.1, 0.7<b<1.0, 0<c<0.08, 0<d≤0.1, 0.001<e≤0.0045, b+c+d+e=1, and
• M3 is Zr, and
• a first composition including LiaZrbOc disposed in grain boundaries between adjacent primary particles of the plurality of primary particles and on a surface of the core to provide a LiaZrbOc shell, the LiaZrbOc having a monoclinic crystalline structure, where 1.9≤a≤2.1, 0.9≤b≤1.1, and 2.9≤c≤3.1,
• wherein the second metals comprises Mg and at least one of Co or Ni, and
• wherein the second composition is different from the first composition, and the second composition has a crystalline structure that is different from the crystal structure of the first composition and the crystal structure of the nickel-containing lithium transition metal oxide, and
• wherein a total amount of the zirconium in the secondary particle is about 0.05 mol % to 0.75 mol % with respect to total moles of the transition metal and the zirconium in the nickel-containing lithium transition metal oxide.