The present invention provides a cathode comprising two or more lithium-containing metal composite oxides, having different potentials versus lithium (Li / Li+) and different impedances, the cathode comprising: (a) a first lithium-containing metal composite oxide; and (b) a second lithium-containing metal composite oxide, which has a high impedance and low potential versus lithium (Li / Li+), compared to those of the first lithium-containing metal composite oxide. In the invention, two or more lithium-containing metal composite oxides are used in combination as cathode components in a battery, whereby, when a short circuit occurs in the battery, the instantaneous flow of a large amount of current can be minimized and, at the same time, the accumulation of heat in the battery can be reduced, thus ensuring the safety of the battery.