Patent ID: 8192715

Claim:
A lithium-containing composite oxide represented by the general formula Li p N x M y O z F a (where N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, Sn, alkaline earth metal elements and transition metal elements other than Co, Mn and Ni, 0.9≦p≦1.2, 0.965≦x<2.00, 0<y≦0.035, 1.9≦z≦4.2, and 0≦a≦0.05, wherein when a powder of the lithium-containing composite oxide is classified into small particles with an average particle size Ds 50 of 2 μm≦Ds 50 ≦8 μm and large particles with an average particle size Dl 50 of 10 μm≦Dl 50 ≦25 μm, the content of the small particles is from 15 to 40% by weight, and the content of the large particles is from 60 to 85% by weight, and 0.01≦ys≦0.06, 0.001≦y≦0.02 and 0.01≦yl/ys≦0.7, where ys is a proportion of the M element in the general formula in the small particles, and yl is a proportion of the M element in the general formula in the large particles.