POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, METHOD OF PREPARING THE SAME, AND POSITIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY WHICH INCLUDE THE POSITIVE ELECTRODE ACTIVE MATERIAL

A method of preparing a positive electrode active material includes mixing a lithium raw material and a nickel-containing transition metal hydroxide precursor containing nickel in an amount of 65 mol % or more based on a total number of moles of transition metals and performing a first heat treatment to prepare a nickel-containing lithium transition metal oxide. The method also includes mixing a boron and carbon-containing raw material and a cobalt-containing raw material with the nickel-containing lithium transition metal oxide to form a mixture, and performing a second heat treatment on the mixture to form a coating material including B and Co on a surface of the lithium transition metal oxide. A positive electrode active material prepared by the preparation method is formed, and a positive electrode for a lithium secondary battery and a lithium secondary battery which include the positive electrode active material.