Enhanced supercapacitor performance of a Cu-Fe ₂ O ₃ /g-C ₃ N ₄ composite material: synthesis, characterization, and electrochemical analysis

A Cu-doped Fe₂O₃/g-C₃N₄ composite, synthesized <i>via</i> a straightforward hydrothermal process with controlled morphologies, represents a significant advancement in supercapacitor electrode materials. This study systematically analyzes the impact of Cu doping in Fe₂O₃ and its synergistic combination with g-C₃N₄ to understand their influence on the electrochemical performance of the resulting composite, focusing on Cu doping in Fe₂O₃ rather than varying Fe₂O₃/g-C₃N₄ content. The comprehensive characterization of these composites involved a suite of physicochemical techniques. X-ray diffraction (XRD) confirmed the successful synthesis of the composite, while field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were employed to investigate the morphological attributes of the synthesized materials. X-ray photoelectron spectroscopy (XPS) spectra confirmed the elemental composition of the composite with 6% Cu doped Fe₂O₃/g-C₃N₄. The composite electrode, which incorporated 6% Cu doped Fe₂O₃ with g-C₃N₄, exhibited exceptional cycling stability, retaining 94.22% of its capacity even after 2000 charge-discharge cycles at a current density of 5 mA cm^-2. Furthermore, this Cu doped Fe₂O₃/g-C₃N₄ composite electrode demonstrated impressive electrochemical performance, boasting a specific capacitance of 244.0 F g^-1 and an impressive maximum energy density of 5.31 W h kg^-1 at a scan rate of 5 mV s^-1. These findings highlight the substantial potential of the Cu doped Fe₂O₃/g-C₃N₄ electrode for supercapacitor applications.