A positive electrode active material including: a lithium complex oxide represented by Formula 1; and a carbon coating layer disposed on the lithium complex oxide, wherein, in a C1s XPS spectrum of the positive electrode active material, a peak intensity of a first peak at a binding energy from about 288 eV to about 293 eV is greater than a peak intensity of a second peak at a binding energy from about 283 eV to about 287 eV, and in an O1s X-ray photoelectron spectrum of the positive electrode active material, a peak intensity of a third peak at a binding energy from about 530.5 eV to about 535 eV is greater than a peak intensity of a fourth peak at a binding energy from about 527.5 electron volts to about 530 electron volts, LiaMbM′cM″dOe.  Formula 1