▎ 摘　　要

NOVELTY - An electrode active material comprises excess lithium transition metal oxide, and a spinel layer formed on the surface of the excess lithium transition metal oxide. USE - Active material used for forming positive electrode of lithium secondary battery (all claimed) for mobile device. ADVANTAGE - The electrode active material has suppressed interfacial side reaction, and excellent rate-limiting characteristics to realize a high-performance battery, thermal stability, and is economically prepared in simple manner without damaging the structure of the active material. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of the electrode active material; (2) a lithium secondary battery; and (3) a positive electrode.