Abstract: An electrochemical cell is made with two asymmetric electrodes and a solid polymer electrolyte. The anode is made from materials such metal hydrides, metals, metal hydroxides or metal oxides. The cathode is made from metal hydrides, metals, metal hydroxides or metal oxides. A solid polymer electrolyte is in intimate contact with and situated between the anode and the cathode. The solid polymer electrolyte is made from a polymeric binder such as polyethylene oxide, polyvinylalcohol, polyvinyl acetate, polyacrylamide, poly(vinylpyrrolidone), poly(2-vinylpyridine), poly(4-vinylpyridine) and polyethyleneimine. The polymeric binder has H.sub.2 SO.sub.4 or H3PO4 dispersed within it.

Abstract: An electrolyte system for use in an electrochemical cell such as a battery or capacitor, and which includes an aqueous electrolyte and a modifier species. The modifier should be adapted to act as a surfactant, as well as reduce oxidation of the electrode materials in the electrochemical cell. The aqueous electrolyte may be, for example, KOH, and the modifier species may be a porphine or porphine derivatives.

Abstract: An electrode for an energy storage device is made from an activated carbon support. The activated carbon has adsorbed onto it a protonated polymer, which has a polyoxometalate absorbed into the polymer. Preferably, the protonated polymer is poly(4-vinylpyridine), and the polyoxometalate is isopolymolybdate. An energy storage device, such as a capacitor, can be made from the modified carbon electrode. A pair of the coated carbon electrodes (13) are placed in contact with an electrolyte to form the device.