Method for Preparing Positive Electrode Active Material

Abstract

A method for preparing a positive electrode active material includes: a step for adding a reaction mixture containing a lithium-raw material and a nickel-manganese-cobalt precursor into a first crucible and performing a first heat treatment at a temperature of 500-800° C. to form a pre-calcinated mixture; a step for extracting the pre-calcinated mixture from the first crucible and pulverizing or classifying the same; and a step for adding the pulverized or classified pre-calcinated mixture into a second crucible and performing a second heat treatment at a temperature of 700-1000° C. under an atmosphere in which an oxygen partial pressure is 20% or less to form a lithium nickel-manganese-cobalt-based positive electrode active material, wherein a volume of the pre-calcinated mixture formed after the first heat treatment is 20-50% with respect to a volume of the reaction mixture added into the first crucible.

Dependencies are inferred from the claim text.