Abstract: An asymmetric electrochemical capacitor has at least a larger capacitance electrode and a smaller capacitance electrode, with an electrolyte therebetween. The larger capacitance electrode has a larger absolute capacitance than the smaller capacitance electrode. The capacitor thus has an overall capacitance which is approximately the absolute capacitance of the smaller capacitance electrode. The electrodes may be made of different materials, with the larger capacitance electrode made of the material having a larger specific capacitance. The larger capacitance electrode may thus be the same physical size as or smaller than the smaller capacitance electrode.