Positive electrode active material, positive electrode including the positive electrode active material, and secondary battery including the positive electrode

Provided is a positive electrode active material including a core and a coating layer disposed on the core, wherein the core includes LiMO, wherein M is at least one element selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), phosphorus (P), aluminum (Al), magnesium (Mg), calcium (Ca), zirconium (Zr), zinc (Zn), titanium (Ti), ruthenium (Ru), niobium (Nb), tungsten (W), boron (B), silicon (Si), sodium (Na), potassium (K), molybdenum (Mo), and vanadium (V), wherein −0.2≤x≤0.2, 0