Highly ordered iron oxide nanotube arrays as electrodes for electrochemical energy storage

Highly ordered α-Fe₂O₃ nanotube arrays have been fabricated by a simple and cost-effective anodization method on iron foils. The α-Fe₂O₃ nanotube arrays exhibit high specific capacitance (138 F•g^{- 1} at 1.3 A•g^{- 1}), remarkable rate capability (91 F•g^{- 1} at 12.8 A•g ^{- 1}) and good cycling stability (the capacitance retention close to 89% after 500 cycles), due to the unique nanostructures of the α-Fe ₂O₃ nanotube arrays, which providing high surface area, fast ion transport pathways and robust structures. These features made the α-Fe₂O₃ nanotube array electrode very attractive for supercapacitor applications.