Patent ID: 11764356

Abstract:
Making a positive electrode active material for lithium ion secondary batteries includes: weighting and mixing lithium carbonate and a compound containing respective metallic elements other than Li in a composition formula LiαNixCoyM21-x-y-zM2zO2+β so as to have a metallic constituent ratio of the formula to obtain a mixture, and firing the mixture to obtain a lithium composite compound. Performing, on the mixture, a first heat treatment at 200° C. to 400° C. for 0.5 to 5 hours to obtain a first precursor. A step of performing a heat treatment on the first precursor under an oxidizing atmosphere at 450° C. to 800° C. for 0.5 to 50 hours, and reacting 92 mass % or more of the lithium carbonate to obtain a second precursor, and a finishing step of performing a heat treatment on the second precursor under an oxidizing atmosphere at 755° C. to 900° C. for 0.5 to 50 hours to obtain the lithium composite compound.