Patent ID: 8691445

Claim:
A positive electrode for a lithium secondary battery, the positive electrode including a positive electrode plate comprising a positive activation material mixture that intercalates and deintercalates lithium ions, wherein the positive activation material mixture comprises a first positive activation material having an average particle diameter D 50 of from 15.1 μm to 18.8 μm and a second positive activation material having an average particle diameter D 50 of from 2.3 μm to 5 μm, wherein a weight ratio of the first positive activation material to the second positive activation material in the positive activation material mixture is from 95:5 to 85:15, wherein the density of the positive electrode plate is at least 3.8 g/cm 3 , and wherein the first positive activation material and the second positive activation material have the same or different chemical composition and are each independently selected from the group consisting of compounds of the following Chemical Formulas 1 and 2, Li x Co 1-y M y A 2 [Chemical Formula 1] Li x Co 1-y M y O 2-Z X z [Chemical Formula 2] wherein 0.9≦x≦1.1, 0≦y≦0.5, 0≦z≦0.5, M is an element selected from the group consisting of Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V, and rare earth elements, A is an element selected from the group consisting of O, F, S, and P, and X is F, S, or P.