POSITIVE ELECTRODE ACTIVE MATERIAL, BATTERY, AND METHOD FOR PRODUCING POSITIVE ELECTRODE ACTIVE MATERIAL

A positive electrode active material comprising a plurality of secondary particles (2, 2a), wherein: each of the secondary particles (2, 2a) includes a plurality of primary particles (1); each of the primary particles (1) contains an olivine-type phosphate compound; carbon is attached to at least part of a surface of the primary particle (1); a cross-sectional surface of the secondary particle (2, 2a) includes a central portion (3a) and a peripheral portion (3b); and a relationship of 0.5 ≤ I/I is satisfied where I is an average value of signal intensities of carbon in the central portion (3a) in TEM-EDS line analysis along a diametrical direction of the secondary particle (2, 2a), and I is an average value of signal intensities of carbon in the peripheral portion (3b) in TEM-EDS line analysis along the diametrical direction of the secondary particle (2, 2a).