CATHODE ACTIVE MATERIAL, LITHIUM SECONDARY BATTERY FOR CONTROLLING IMPURITIES OR SWELLING CONTAINING SAME, AND PREPARATION METHOD OF CATHODE ACTIVE MATERIAL WITH IMPROVED PRODUCTIVITY

摘要

The present invention relates to: a cathode active material represented by the following chemical formula 1, wherein a metal cation represented by M having a larger ionic diameter than that of a Ni cation is contained in a Li cation site or an empty space in a crystal lattice to prevent the mixing of Ni cations in a Li layer; a lithium secondary battery containing the same; and a preparation method of a cathode active material with improved productivity. LiaNixMnyCozMwO2-tAt (1) (In said formula, a, x, y, w, M, A, z, and t are as defined in the specification)