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

Provided are a positive electrode active material comprising at least one secondary particle comprising an agglomerate of primary macro particles, a method for preparing the same and a lithium secondary battery comprising the same. Further provided is a positive electrode active material comprising secondary particles with improved resistance by simultaneously growing the average particle size (D50) and the crystal size of the primary macro particles. Thus, it is possible to provide a nickel-based positive electrode active material with high press strength, long life and good gas performance.