Elevation of the Electrochemical Stability Performance of Co₃O₄/g-C₃N₄ for an Asymmetric Supercapacitor

Transition metal oxides play a crucial role in the research and application of electrode materials for supercapacitors owing primarily to their significant cost effectiveness, high theoretical energy storage capacity, and favorable reversibility. However, their intrinsic low conductivity and sluggish reaction kinetics often lead to limited specific capacitance and slow rate capability in devices. To address these issues, this study introduces a novel composite material, namely, the combination of Co3O4 with graphitic carbon nitride (g-C3N4). The design of this Co3O4/g-C3N4 composite material aims to enhance the electrochemical performance by harnessing the synergistic properties of the two materials. Detailed characterization results unveil that, in comparison to standalone Co3O4 electrodes, the composite electrode material demonstrates a greater electrochemical reaction area. Consequently, the composite material exhibits a prolonged discharge time and higher capacity, thereby augmenting overall capacitance performance. Even after extended cycling, the composite material maintains an impressive capacity retention rate of 90.4%. Additionally, density functional theory calculations reveal that the electrode possesses a relatively small band gap and excellent conductivity. Through this innovative material design strategy, Co3O4/g-C3N4 emerges as a promising choice for efficient and high-performance supercapacitors.