Fe2O3 sheets grown on nickel foam as electrode material for electrochemical capacitors

• Fe2O3 sheets have been synthesized on nickel foam by a simple template-free growth process and heat treatment.
• The Fe2O3 electrode exhibits a specific capacitance of 147 F g−1 at 0.36 A g−1 and 98 F g−1 at 3.6 A g−1.
• The as-prepared Fe2O3 electrode presents a wider potential window of 1.0 V.

Fe2O3 sheets have been synthesized on nickel foam by a simple template-free growth process and heat treatment. Structural characterization by SEM, TEM and BET indicates that the neighboring porous Fe2O3 sheets form a open reaction space on the surface of the nickel foam skeletons. The sheets are confirmed to be pure Fe2O3 phase by X-ray diffraction. The electrochemical capacitance behaviors of Fe2O3 sheets electrode are investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy tests. The results show that the Fe2O3 sheets electrode exhibits a specific capacitance as high as 147 F g−1 at 0.36 A g−1 in 1 mol dm−3 Li2SO4 electrolyte, good cycling stability, and with a wide potential window of 1.0 V. The superior capacitance of Fe2O3 sheets electrode might be attributed to its unique porous structure for easy access of electrolyte ions and high electrochemical activity.