A method of storing charge comprising the steps of providing a capacitor comprising an anode, a cathode, and an electrolyte, wherein the electrolyte comprises a nonaqueous liquid of sufficient dielectric constant to dissociate salts soluble in the nonaqueous liquid, a composite comprising a prefabricated porous carbon electrode structure or a carbon foam substrate that is a prefabricated paper structure and a coating deposited by infiltrating the structure with iron oxide via self-limiting electroless deposition on the surface.