| abstract |
The present invention relates to a positive electrode active material for a lithium secondary battery, and the positive electrode active material has the following Chemical Formula 1 having a higher Co concentration in the surface layer from the surface to a depth of 10 microns.n n n [Formula 1]n n n Li 1 + x Mn 2-x Co x O 4 n n n (Wherein -0.1? X? 0.1)n n n The active material of Chemical Formula 1 is prepared by mixing and heating a lithium salt, cobalt salt, alcohol, and chelating agent to prepare a cobalt material in a sol or gel state, and mixing the cobalt material in a sol or gel state with Li 2 MnO 4. And a step of heat treating the mixture.n n n In this active material, Co, which is present at a high concentration in the surface layer, prevents the elution of manganese, so the cycle life at high temperature is improved by 20% or more compared to LiMn 2 O 4 . |