Abstract: Disclosed are a method for preparing a positive electrode active material for a lithium secondary battery and a positive electrode active material for a lithium secondary battery, the method including: preparing a mixture of a precursor represented by Chemical Formula 1 below, a lithium composite oxide represented by Chemical Formula 2 below and capable of intercalating/deintercalating lithium ions, and a lithium feed material; and firing the prepared mixture: A(OH)2-a ??[Chemical Formula 1] Li[LizA(1-z-a)Da]EbO2-b ??[Chemical Formula 2]

Abstract: Disclosed are a method for preparing a positive electrode active material for a lithium secondary battery and a positive electrode active material for a lithium secondary battery, the method including: preparing a mixture of a precursor represented by Chemical Formula 1 below, a lithium composite oxide represented by Chemical Formula 2 below and capable of intercalating/deintercalating lithium ions, and a lithium feed material; and firing the prepared mixture: A(OH)2-a??[Chemical Formula 1] Li[LizA(1-z-a)Da]EbO2-b??[Chemical Formula 2]

Abstract: Provided are a cathode active material for a lithium secondary battery and a lithium secondary battery including the same. The cathode active material includes a lithium composite oxide represented by the following Chemical Formula 1. Li[LizA]O2 A={M11-x-y(M10.78Mn0.22)x}M2y??[Chemical Formula 1] In Chemical Formula, M1 and M2 are independently one or more selected from a transition element, a rare earth element, or a combination thereof, M1 and M2 are elements that are different from each other, ?0.05?z?0.1, 0.8?x+y?1.8, and 0.05?y?0.35, and Ni has an oxidation number of 2.01 to 2.4.