Patent attributes
A lithium nickel cobalt manganese composite oxide cathode material includes a plurality of secondary particles. Each secondary particle consists of aggregates of fine primary particles. Each secondary particle includes lithium nickel cobalt manganese composite oxide, which is expressed as LiaNi1-b-cCobMncO2. An average formula of each secondary particle satisfies one condition of 0.9≦a≦1.2, 0.08≦b≦0.34, 0.1≦c≦0.4, and 0.18≦b+c≦0.67. The lithium nickel cobalt manganese composite oxide has a structure with different chemical compositions of primary particles from the surface toward core of each of the secondary particles. The primary particle with rich Mn content near the surface and the primary particle with rich Ni content in the core of the secondary particle of the lithium nickel cobalt manganese composite oxide cathode material have provided the advantages of high safety and high capacity.