POSITIVE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, METHOD FOR PRODUCING POSITIVE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, POSITIVE ELECTRODE FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, AND ENERGY STORAGE APPARATUS

Provided is a positive active material for a nonaqueous electrolyte secondary battery which contains a lithium transition metal composite oxide, the lithium transition metal composite oxide having an α-NaFeOstructure, containing Ni, Co and Mn as a transition metal (Me), and having an X-ray diffraction pattern attributable to a space group R3-m, in which a ratio of the full width at half maximum of a diffraction peak of the (003) plane to the full width at half maximum of a diffraction peak of the (104) plane, (003)/(104) at a Miller index hkl in X-ray diffraction measurement using a CuKα ray is 0.810 to 0.865, and a crystallite size is 410 Å or more.