Metal-Doped Cobalt Precursor for Preparing Positive Electrode Active Material for Secondary Battery

Provided is a cobalt precursor for preparing a lithium cobalt oxide of a layered structure which is included in a positive electrode active material, wherein the cobalt precursor is cobalt oxyhydroxide (CoM′OOH) doped with, as dopants, magnesium (Mg) and M′ different from the magnesium.