POSITIVE ELECTRODE ACTIVE MATERIAL, ELECTRODE, AND BATTERY

A positive electrode active material includes olivine lithium manganese iron phosphate, wherein the olivine lithium manganese iron phosphate contains a first dopant at a phosphorus site and a second dopant at an oxygen site, the first dopant has a valence of +4 and a coordination number of 4 at the phosphorus site, and the second dopant has a valence of −1 at the oxygen site.