Eamex Corp. (Eamex) is a Japanese company that has developed a high energy density capacitor using a proprietary polymeric actuator with metal plating that serves as an electrode.
The capacitor and methods of making it are covered by U.S. Patent No. 7,169,822 (‘822 patent). The ‘822 patent is directed to a polymeric actuator (1) comprising an ion-exchange resin (2) in the form of a flat plate or film and metal electrodes (3a, 3b) attached to the surface of the resin by chemical plating techniques.
Lead wires (4a, 4b) provide an electrical connection between the electrodes (3a, 3b) and a power source (5). The metal electrodes (3a, 3b) are insulated from each other, and application of a potential difference between the electrodes causes the ion-exchange resin product to bend or deform.
According to Eamex’s web site and this Greentech Media article, the electrodes of the patented actuator have greatly increased surface area, and the energy density per unit volume reaches up to 600 Wh/L, which is equivalent to that of a lithium-ion secondary battery.