Positive electrode active material for use in secondary batteries and method for production thereof

Abstract

The invention provides a secondary battery positive electrode active material including an oxide containing Li, Mn, and Ti, wherein the oxide has a Li content of 43 to 60 mol %, a Mn content of 22 to 35 mol %, and a Ti content of 7 to 29 mol %, the oxide has an X-ray diffraction pattern that is measured using CuKα as an X-ray source and has a maximum X-ray diffraction peak exhibiting the highest peak intensity and existing at an angle in the range of 43 to 45 degrees, the oxide satisfies the formula 0.70<a/(a+b)<0.90, wherein a is the intensity of the maximum X-ray diffraction peak and b is the intensity of a maximum peak among X-ray diffraction peaks in the 20 range of 15 to 22 degrees, and the oxide has a lattice constant of 4.10 to 4.14 Å.