Cathode active material, its production process, and positive electrode for lithium ion secondary battery

Abstract

To provide a cathode active material with which it is possible to obtain a lithium ion secondary battery having a high discharge capacity and being excellent in the cycle characteristic, and its production process. A cathode active material, comprising particles of a lithium-containing composite oxide, the lithium-containing composite oxide being represented by LiαNiaCobMncTidMeO2+δ wherein α is from 1 to 1.8, a is from 0.15 to 0.5, b is from 0 to 0.09, c is from 0.33 to 0.8, d is from 0.01 to 0.1, e is from 0 to 0.1, δ is from 0 to 0.8, a+b+c+d+e=1, and M is Mg, Al, Ca or the like, wherein in an X-ray diffraction pattern, the ratio (H020/H003) of the height of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height of a peak of (003) plane assigned to a crystal structure with space group R-3m is at least 0.02, and D90/D10 is at most 4.

Dependencies are inferred from the claim text.