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

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 LiMnOhaving a stoicheiometric spinel structure with a flat level voltage profile in the range of 2.5 V to 3.3V. [chemical formula 1] xLiMnO· (1-x)LiMO, wherein 0