Lithium secondary battery positive electrode material for improving output characteristics and lithium secondary battery including the same

A lithium secondary battery positive electrode material consisting essentially of:

• a mixed positive electrode active material comprising a 3-component system lithium-containing metal oxide having a layered structure expressed as following Chemical Formula 1 and a metal oxide having an olivine structure expressed as following Chemical Formula 2;
• and
• two conductive materials having particle shapes and sizes different from each other:
• Li1+aNixCoyMn1-x-yO2, 0≦a<0.5, 0<x<1, 0<y<0.5 Chemical Formula 1
• AxMyM′zXO4 Chemical Formula 2
• where, A is at least one selected from alkali metals, M and M′ are at least one selected from transition metal elements, X is any one selected from the group consisting of P, Si, S, As, Sb, and combinations thereof, and x+y+z=2,
• wherein the metal oxide having the olivine structure, which is expressed as Chemical Formula 2, is contained in a ratio of about 10 wt % to about 40 wt % with respect to the 3-component system lithium-containing metal oxide, which is expressed as Chemical Formula 1, on the basis of the total weight of the mixed positive electrode active material, and
• wherein the two conductive materials having the particle shapes and sizes different from each other are graphite and acetylene black,
• wherein the two conductive materials having the particle shapes and sizes different from each other, which are formed of graphite and acetylene black, have a content of about 0.5 wt % to about 15 wt % with respect to the total weight of the lithium secondary battery positive electrode material,
• wherein the acetylene black has a content of about 3 wt % to about 10 wt % with respect to the total weight of the lithium secondary battery positive electrode material,
• wherein a content ratio of acetylene black to graphite is 2:1, and
• wherein a particle size of the 3-component system lithium-containing metal oxide of the Chemical Formula 1 is larger than that of the metal oxide of the Chemical Formula 2, so that a surface area of the 3-component system lithium-containing metal oxide of the Chemical formula 1 is 0.3 to 1 m2/g and a surface area of the metal oxide of the Chemical Formula 2 is 10 to 40 m2/g.