METHOD OF PRODUCING CATHODE ACTIVE MATERIAL, AND METHOD OF PRODUCING LITHIUM ION BATTERY

A major object is to provide a method of producing a cathode active material having a high average discharge potential, and a high degree of stability at high potential. The method includes: a step of preparing a Na-doped precursor of making a sodium-containing transition metal oxide having the P2 structure belonging to a space group of P6/mmc; and an ion exchange step of substituting lithium for at least part of sodium contained in the sodium-containing transition metal oxide by the ion exchange method, wherein in the ion exchange step, at least lithium iodide is used as a Li ion source.