POSITIVE ELECTRODE ACTIVE MATERIAL, POSITIVE ELECTRODE, AND RECHARGEABLE LITHIUM BATTERIES

A positive electrode active material including a first positive electrode active material including a lithium nickel-manganese-based composite oxide having a nickel content of greater than or equal to about 60 mol% based on about 100 mol% of a total metal excluding lithium and including secondary particles made by agglomerating a plurality of primary particles wherein an average particle diameter (D50) of the secondary particle is about 10 µm to about 20 µm, a second positive electrode active material including a lithium nickel-manganese-based composite oxide having a nickel content of greater than or equal to about 60 mol% based on about 100 mol% of a total metal excluding lithium and including single particles wherein an average particle diameter (D50) of each of the single particles is about 2 µm to about 8 µm, and a third positive electrode active material including particles including lithium transition metal phosphate.