A lithium secondary battery comprising: a positive electrode which includes a positive electrode active material layer including a lithium nickel cobalt manganese-based oxide represented by [Formula 1] below and a lithium cobalt-based oxide represented by [Formula 2] below in a weight ratio of 50: 50 to 80: 20; a negative electrode which includes a negative electrode active material layer including a negative electrode active material; and an electrolyte including an organic solvent and a lithium salt, wherein an average particle diameter of primary particles of the lithium nickel cobalt manganese-based oxide is 3 um or more as determined by the method in the description, and the organic solvent comprises propyl propionate and a cyclic carbonate solvent containing ethylene carbonate and propylene carbonate, wherein the ethylene carbonate is included in an amount of 23 wt% or less in the organic solvent: [Formula 1] Li x [Ni y Co z Mn w M 1 v]O 2-p A p wherein, in [Formula 1], M 1 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, A comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 1.0≤x≤1.30, 0.3≤y<1, 0<z≤0.6, 0<w≤0.6, 0≤v≤0.2, y+z+w+v=1 and 0≤p≤0.2; [Formula 2] LiCo 1-a M 2 a O 2-b B b wherein, in Formula 2, M 2 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, B comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 0≤a≤0.2 and 0≤b≤0.1. a positive electrode which includes a positive electrode active material layer including a lithium nickel cobalt manganese-based oxide represented by [Formula 1] below and a lithium cobalt-based oxide represented by [Formula 2] below in a weight ratio of 50: 50 to 80: 20; a negative electrode which includes a negative electrode active material layer including a negative electrode active material; and an electrolyte including an organic solvent and a lithium salt, wherein an average particle diameter of primary particles of the lithium nickel cobalt manganese-based oxide is 3 um or more as determined by the method in the description, and the organic solvent comprises propyl propionate and a cyclic carbonate solvent containing ethylene carbonate and propylene carbonate, wherein the ethylene carbonate is included in an amount of 23 wt% or less in the organic solvent: [Formula 1] Li x [Ni y Co z Mn w M 1 v]O 2-p A p wherein, in [Formula 1], M 1 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, A comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 1.0≤x≤1.30, 0.3≤y<1, 0<z≤0.6, 0<w≤0.6, 0≤v≤0.2, y+z+w+v=1 and 0≤p≤0.2; [Formula 2] LiCo 1-a M 2 a O 2-b B b wherein, in Formula 2, M 2 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, B comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 0≤a≤0.2 and 0≤b≤0.1. M 1 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, A comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 1.0≤x≤1.30, 0.3≤y<1, 0<z≤0.6, 0<w≤0.6, 0≤v≤0.2, y+z+w+v=1 and 0≤p≤0.2; [Formula 2] LiCo 1-a M 2 a O 2-b B b wherein, in Formula 2, M 2 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, B comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 0≤a≤0.2 and 0≤b≤0.1. M 2 comprises at least one element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, B comprises at least one element selected from the group consisting of F, Cl, Br, I, At, and S, and 0≤a≤0.2 and 0≤b≤0.1.