Solid phase synthesis method of positive electrode active material of nickel-rich lithium composite transition metal oxide in a form of a single particle, positive electrode active material of nickel-rich lithium composite transition metal oxide in a form of a single particle formed therefrom, positive electrode and lithium secondary battery containing the same

Abstract

A positive electrode active material and a method of making the same are disclosed herein. In some embodiments, a method includes mixing transition metal raw powders including a nickel raw powder to prepare a first mixture, where the first mixture has a molar ratio of lithium to total transition metals of 0.95 to 1.02, and where a molar ratio of nickel to total transition metals is 80 mol % or more, sintering the first mixture in an oxygen-containing atmosphere, and cooling the sintered first mixture to obtain a first sintered product, mixing the first sintered product with a second lithium raw material to prepare a second mixture, where the second mixture has molar ratio of lithium to total transition metals of 1.00 to 1.09, and sintering the second mixture in the oxygen-containing atmosphere to prepare a lithium composite transition metal oxide in the form of a single particle.