Plate-like NiCo2O4 integrated with g-C3N4 nanostructures for hybrid supercapacitors and green energy technologies

The development of nanostructured electrode materials for supercapacitors and green energy applications remains a challenging task, particularly in achieving maximum surface area for optimal electrode-electrolyte interaction. In this study, we synthesize interconnected nanostructured NiCo₂O₄/g-C₃N₄ using a cost-effective hydrothermal method. The NiCo₂O₄/g-C₃N₄ nanocomposite undergoes comprehensive characterization to analyze its structural, morphological, and electrochemical properties using various techniques. Electrodes fabricated from the NiCo₂O₄/g-C₃N₄ material exhibit a high specific capacity (Qs) of 203 C/g. Additionally, the as-fabricated asymmetric supercapacitor (ASC) achieves a remarkable energy density (Ed) of 87.3 Wh/kg and a power density (Pd) of 1038 W/kg at 1.4 A/g, with superior cycling performance, retaining 95.04 % of its capacity after 10,000 cycles. Furthermore, we evaluate the modified NiCo₂O₄/g-C₃N₄ electrodes for their electrocatalytic performance in the oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The results indicate that the NiCo₂O₄/g-C₃N₄ electrode exhibits the best OER performance (overpotential (η) = 287 mV and Tafel slope = 121 mV/dec at 10 mA/cm²) and demonstrates excellent HER activity (η = 336 mV and Tafel slope = 93 mV/dec at −10 mA/cm²) with exceptional cyclic stability. This research highlights the potential of NiCo₂O₄/g-C₃N₄ as a promising material for supercapacitor and green energy technology.