α‐Fe 2 O 3 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 Fe 2 O 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 Fe 2 O 3 nanocubes is presented via the hydrothermal method using a mixed solvent system. The annealed α‐Fe 2 O 3 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 Fe 2 O 3 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 Fe 2+ /Fe 3+ ions. Further, the assembled two‐electrode asymmetric device α‐Fe 2 O 3 //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‐Fe 2 O 3 nanocubes as a promising material for the development of next‐generation supercapacitors, with profound implications for the advancement of sustainable energy storage solutions.