Composite positive active material for lithium secondary battery, method of preparing composite positive active material, and lithium secondary battery including composite positive active material

Abstract

Provided are a composite positive active material for a lithium secondary battery, a method of preparing the composite positive active material, and a lithium secondary battery containing a positive electrode including the composite positive active material. The composite positive active material may include a lithium cobalt-based oxide, wherein a particle coating portion may be in an island form on a surface of the lithium cobalt-based oxide, the particle coating portion including a first coating layer containing lithium titanium-based oxide, a lithium-deficient cobalt oxide phase having a molar ratio of lithium to cobalt of 0.9 or less may be included in an inner portion of the lithium cobalt-based oxide corresponding to the particle coating portion, and the composite positive active material may include a first lithium zirconium-based oxide spaced apart from a surface of the lithium cobalt-based oxide.