▎ 摘　　要

NOVELTY - Positive electrode active material comprises a core and a coating layer arranged on the core, where the core comprises a lithium oxide compound (I). The coating layer comprises carbon-based particles comprising a structure in which graphene sheets are connected to each other, and a D/G peak ratio is 0.9 to 1.3 in Raman spectrum measurement. USE - The active material is useful in a positive electrode for a secondary battery (all claimed) for a medium-to-large device chosen from electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems as a power source. ADVANTAGE - The active material has improved electrical conductivity, improved input/output characteristics and lifespan characteristics, overall battery performance, thermal conductivity, heat resistance and mechanical strength, blocks contact between core and external moisture, prevents structural collapse of core, and suppresses transition metal elution problem. DETAILED DESCRIPTION - Positive electrode active material comprises a core and a coating layer arranged on the core, where the core comprises a lithium oxide compound of formula: Li1+xMyO2+z (I). The coating layer comprises carbon-based particles comprising a structure in which graphene sheets are connected to each other, and a D/G peak ratio is 0.9 to 1.3 in Raman spectrum measurement. M = at least one element chosen from Ni, Co, Mn, Fe, P, Al, Mg, Ca, Zr, Zn, Ti, Ru, Nb, W, B, Si, Na, K, Mo, and V; x = -0.2-0.2; y = 0-2;and z = 0-2.