A rechargeable lithium battery, comprising: a positive electrode comprising a positive current collector and a positive active mass layer on the positive current collector, the positive active mass layer comprising a composite oxide of lithium and at least one of cobalt, manganese, nickel, or a combination thereof as a positive active material and activated carbon; a negative electrode comprising a negative current collector and a negative active mass layer on the negative current collector, the negative active mass layer comprising soft carbon as a negative active material; and an electrolyte, wherein Equation 1 is satisfied: 0.3 ≤ A / B ≤ 2.222 wherein, in Equation 1, A satisfies Equation 2, and B satisfies Equation 3: 0.01 ≤ active mass density g / cm 3 g / cc of the positive active mass layer / thickness μm of the positive electrode 2 ≤ 0.1, 0.01 ≤ active mass density g / cm 3 g / cc of the negative active mass layer / thickness μm of the negative electrode 4 ≤ 0.05 and wherein the active mass density of the positive active mass layer is about 0.5 g/cc to about 4.0 g/cc, the thickness of the positive electrode is about 30 μm to about 200 μm, the active mass density of the negative active mass layer is about 0.5 g/cm 3 (g/cc) to about 2.5 g/cm 3 (g/cc), and the thickness of the negative electrode is about 30 μm to about 200 μm; wherein in the positive active mass layer, the positive active material and activated carbon is included in an amount of about 85 wt% to about 98 wt% based on the total weight of the positive active material layer; and wherein the positive active mass layer comprises the positive active material and the activated carbon in a weight ratio of 77:23 to 98:2. a positive electrode comprising a positive current collector and a positive active mass layer on the positive current collector, the positive active mass layer comprising a composite oxide of lithium and at least one of cobalt, manganese, nickel, or a combination thereof as a positive active material and activated carbon; a negative electrode comprising a negative current collector and a negative active mass layer on the negative current collector, the negative active mass layer comprising soft carbon as a negative active material; and an electrolyte, wherein Equation 1 is satisfied: 0.3 ≤ A / B ≤ 2.222 wherein, in Equation 1, A satisfies Equation 2, and B satisfies Equation 3: 0.01 ≤ active mass density g / cm 3 g / cc of the positive active mass layer / thickness μm of the positive electrode 2 ≤ 0.1, 0.01 ≤ active mass density g / cm 3 g / cc of the negative active mass layer / thickness μm of the negative electrode 4 ≤ 0.05 A satisfies Equation 2, and B satisfies Equation 3: 0.01 ≤ active mass density g / cm 3 g / cc of the positive active mass layer / thickness μm of the positive electrode 2 ≤ 0.1, 0.01 ≤ active mass density g / cm 3 g / cc of the negative active mass layer / thickness μm of the negative electrode 4 ≤ 0.05 and wherein the active mass density of the positive active mass layer is about 0.5 g/cc to about 4.0 g/cc, the thickness of the positive electrode is about 30 μm to about 200 μm, the active mass density of the negative active mass layer is about 0.5 g/cm 3 (g/cc) to about 2.5 g/cm 3 (g/cc), and the thickness of the negative electrode is about 30 μm to about 200 μm; wherein in the positive active mass layer, the positive active material and activated carbon is included in an amount of about 85 wt% to about 98 wt% based on the total weight of the positive active material layer; and wherein the positive active mass layer comprises the positive active material and the activated carbon in a weight ratio of 77:23 to 98:2.