A high-output lithium secondary battery comprising: a cathode comprising, as cathode active materials, a first cathode active material represented by Formula 1 below and having a layered structure and a second cathode active material represented by Formula 2 below and having a spinel structure, wherein an amount of the second cathode active material is between 40 and 100wt% based on a total weight of the first and second cathode active materials, in which the first cathode active material has an average particle diameter with respect to capacity of 0.03 to 0.1 μm/mAh and a powder conductivity of 1x10 -3 S/cm or greater to less than 10x10 -3 S/cm at a powder density of 2.65 to 2.85 g/cm 3, and the second cathode active material has an average particle diameter with respect to capacity of 0.1 to 0.2 μm/mAh and a powder conductivity of 1x10 -5 S/cm or greater to less than 10x10 -5 S/cm at a powder density of 2.65 to 2.85 g/cm 3; an anode comprising crystalline graphite having a specific surface area with respect to capacity of 0.005 to 0.013 m 2 /mAh as an anode active material; and a separator: Li x (Ni v Mn w CoyM z)O 2-t A t wherein 0.8 < x≤1.3, 0≤v≤0.9, 0≤w≤0.9, 0≤y≤0.9, 0≤z≤0.9, x+v+w+y+z=2, and 0≤t < 0.2; M refers to at least one metal or transition metal cation having an oxidation number of +2 to +4; and A is a monovalent or divalent anion, Li a Mn 2-b M' b O 4-c A' c wherein 0.8 < a≤1.3, 0≤b≤0.5, and 0≤c≤0.3; M' refers to at least one metal or transition metal cation having an oxidation number of +2 to +4; and A' is a monovalent or divalent anion. a cathode comprising, as cathode active materials, a first cathode active material represented by Formula 1 below and having a layered structure and a second cathode active material represented by Formula 2 below and having a spinel structure, wherein an amount of the second cathode active material is between 40 and 100wt% based on a total weight of the first and second cathode active materials, in which the first cathode active material has an average particle diameter with respect to capacity of 0.03 to 0.1 μm/mAh and a powder conductivity of 1x10 -3 S/cm or greater to less than 10x10 -3 S/cm at a powder density of 2.65 to 2.85 g/cm 3, and the second cathode active material has an average particle diameter with respect to capacity of 0.1 to 0.2 μm/mAh and a powder conductivity of 1x10 -5 S/cm or greater to less than 10x10 -5 S/cm at a powder density of 2.65 to 2.85 g/cm 3; an anode comprising crystalline graphite having a specific surface area with respect to capacity of 0.005 to 0.013 m 2 /mAh as an anode active material; and a separator: Li x (Ni v Mn w CoyM z)O 2-t A t wherein 0.8 < x≤1.3, 0≤v≤0.9, 0≤w≤0.9, 0≤y≤0.9, 0≤z≤0.9, x+v+w+y+z=2, and 0≤t < 0.2; M refers to at least one metal or transition metal cation having an oxidation number of +2 to +4; and A is a monovalent or divalent anion, Li a Mn 2-b M' b O 4-c A' c wherein 0.8 < a≤1.3, 0≤b≤0.5, and 0≤c≤0.3; M' refers to at least one metal or transition metal cation having an oxidation number of +2 to +4; and A' is a monovalent or divalent anion. M refers to at least one metal or transition metal cation having an oxidation number of +2 to +4; and A is a monovalent or divalent anion, M' refers to at least one metal or transition metal cation having an oxidation number of +2 to +4; and A' is a monovalent or divalent anion.