MIXED POSITIVE ELECTRODE ACTIVE MATERIAL WITH IMPROVED OUTPUT CHARACTERISTICS AND LITHIUM SECONDARY BATTERY COMPRISING SAME

摘要

The present invention relates to a mixed positive electrode active material and to a lithium secondary battery comprising the same, wherein the mixed positive electrode active material comprises lithium manganese oxide expressed by the following chemical formula 1 and Li 4 Mn 5 O 12 having a stoicheiometric spinel structure with a flat level voltage profile in the range of 2.5 V to 3.3V. [chemical formula 1] xLi 2 MnO 3 · (1-x)LiMO 2 , wherein 0x1, and M is one element selected from a group consisting of Al, Mg, Mn, Ni, Co, Cr, V and Fe, or two or more elements selected from the group and applied at the same time. The mixed positive electrode active material and the lithium secondary battery comprising the same have enhanced stability, and in which said Li 4 Mn 5 O 12 supplements a low output in a low SOC range to maintain an output at the level higher than a required output level, thereby widening an available SOC range. The mixed positive electrode active material and the lithium secondary battery comprising the same may be suitably used in PHEV, EV or the like.