POSITIVE ELECTRODE ACTIVE MATERIAL AND LITHIUM SECONDARY BATTERY USING SAME

Disclosed is a cathode active material for secondary batteries comprising one or more compounds having a layered-crystal structure, represented by the following Formula 1, wherein a transition metal layer contains Li, in an amount lower than 20%, based on a total amount of a transition metal site, and a ratio of Ni positioned in a lithium layer, that is, a cation mixing ratio is 1% to 4.5%, based on a total amount of a lithium site in the lithium layer to stably support the layered-crystal structure. (1-s-t)[Li(LiMnNiCo)O]*s[LiCO]*t[LiOH] (1) wherein 0