High-performance α-Fe2O3 nano cubes as anode for supercapacitors

Abundant availability, high theoretical specific capacitance and low cost of transition metal oxides such as iron oxides, make them attractive as electrode materials for energy storage. In order to achieve improved performance, high conductivity, shorter ion-diffusion path, and faster ion accessibility, rational design of morphology of electrode material is highly desirable. We have successfully synthesized mesoporous alpha-Fe2O3 nanocubes to achieve high specific capacitance and better retention. The as-prepared and annealed alpha-Fe2O3 nanocubes show high reversible redox activity along with good thermodynamic stability. These nanostructure give rise to high specific capacitance and similar to 90 % of the capacitance can be retained even after 1000 redox cycles, suggesting good cyclic stability. The electrochemical performance of mesoporous alpha-Fe2O3 nanocubes is attributed to the morphological features, which results in efficient K+ ion transport into the pores. A two electrode alpha-Fe2O3//NiO device is fabricated, which shows excellent power and energy density of similar to 627 W/kg and similar to 23.32 Wh/kg, respectively. Our work demonstrates that 3D nanoporous alpha-Fe2O3 electrodes forms promising material system as anode for improved charge storage performance.