METHOD FOR MANUFACTURING POSITIVE ELECTRODE ACTIVE MATERIAL

The present invention relates to a method of preparing a positive electrode active material which includes the steps of forming a pre-sintered product by mixing a transition metal precursor having a nickel content of 70 atm% or more and a lithium raw material and performing primary sintering, and forming a lithium composite transition metal oxide by performing secondary sintering on the pre-sintered product, wherein the primary sintering is performed such that a ratio of a spinel phase of the pre-sintered product is in a range of 7% to 16%.