α-Fe2O3 Nanocubes as High-Performance Anode for Supercapacitor

Abstract

The ability to store charge through both Faradaic and non-Faradaic mechanisms in transition metal oxide-based nanomaterials have made them a popular choice for use as electrode materials in energy storage devices. Of these nanostructured iron oxides, especially Fe₂O_3, forms one of the most preferred choices of material as supercapacitor anode due to low cost, non-toxicity, high abundance and availability of variable oxidation states. In this study, the synthesis of nanostructured Fe₂O₃ nanocubes is presented via the hydrothermal method using a mixed solvent system. The annealed α-Fe₂O₃ nanocubes show a superior specific capacitance of 908 F g⁻¹ as compared to 796 F g⁻¹ for the as prepared samples at a current density of 2A g⁻¹, The high specific capacity of Fe₂O₃ nanocubes can be ascribed to the availability and exposure of active sites for charge storage, low charge transfer resistance (Rct) and reversible electrochemical reactions involving Fe²⁺/Fe³⁺ ions. Further, the assembled two-electrode asymmetric device α-Fe₂O₃//NiO shows the energy density of 25.31Wh Kg⁻¹ at a power density of 759.3 W Kg⁻¹, with capacitance retention of 70% after 1000 cycles. These findings underscore the viability of α-Fe₂O₃ nanocubes as a promising material for the development of next-generation supercapacitors, with profound implications for the advancement of sustainable energy storage solutions.