Positive Electrode Active Material for Secondary Battery, Method for Preparing the Same, and Lithium Secondary Battery Including the Same

A positive electrode active material for a secondary battery is provided. The positive electrode active material being a lithium cobalt-based oxide includes a doping element M. A lithium cobalt-based oxide particle containing the doping element M in an amount of 3,000 ppm or more, wherein in a bulk portion corresponding to 90% of a core side among the radius from a core of the particle to a surface thereof, the doping element M in the lithium cobalt-based oxide particle is contained at a constant concentration, and in a surface portion from the surface of the particle to 100 nm in a core direction, the doping element M is contained at a concentration equal to or higher than that in the bulk portion and has a concentration in which the concentration thereof is gradient gradually decreased in the core direction from the surface of the particle.