| abstract |
Iron oxide film directly grown on iron, steel, or other substrates by chemical or electrochemical oxidation is a promising material for energy storage through surface adsorption of static charges. As the electrode materials of energy-storage devices, the iron oxide has a chemical composition of Fe x O y H z , where 1.0≦x≦3.0, 0.0≦y≦4.0, and 0 0≦z≦1.0. An aqueous or organic solution of a metallic salt including sulfates, sulfites, hydroxides, chlorides, phosphates and nitrates is used as electrolyte for the electrochemical devices. Cyclic voltammetry indicates that the iron-oxide electrodes in the electrolytes can store charges as high as 0.5 F/cm 2 or 320 F/g of the electrode materials. Electrochemical capacitors using the iron oxide as the electrode material is an economical and viable power source for use in portable electronics, power tools, and electrical vehicles. |