Positive electrode active material with improved output and lithium secondary battery comprising the same

Abstract

A mixed positive electrode active material comprising a lithium manganese oxide represented by following [Chemical Formula 1] and a second positive electrode active material represented by following [Chemical Formula 2], and a lithium secondary battery comprising the same are disclosed. aLi2MnO3.(1−a)LixMO2  [Chemical Formula 1] In [Chemical Formula 1], 0<a<1, 0.9≦x≦1.2, and M is at least one element selected from the group consisting of Al, Mg, Mn, Ni, Co, Cr, V and Fe. Li4-xMn5-2x-yCO3xMyO12  [Chemical Formula 2] In [Chemical Formula 2], 0<x<1.5, 0≦y<0.5, and M is at least one of transition metal elements. By comprising Mn-rich and Co-doped Li4Mn5O12, a rapid output decrease at a low SOC section may be relaxed to enlarge an available SOC section. Improved output may be obtained throughout an entire SOC section when compared with a case using pure Li4Mn5O12.

Dependencies are inferred from the claim text.