Three Dimensional Graphene Aerogel Encapsulated NiCo₂O₄ Sea Urchin-like Nanospheres for Supercapacitor Application

NiCo2O4 nanostructures have emerged as a promising candidate for high-performance supercapacitor electrodes. In this study, we synthesized NiCo2O4 nanoarchitectures via a hydrothermal method and further enhanced their electrochemical properties by integrating a three-dimensional graphene (3DG) network. This 3DG coating effectively prevents the aggregation of NiCo2O4 nanoparticles, creates hierarchical porous channels, and significantly expands the active surface area at the nanoscale. The optimized 3DG/NiCo2O4 nanocomposite demonstrates exceptional charge storage capabilities, achieving a high specific capacitance of 700.73 F/g at 1 A/g and outstanding cycling stability with 96.24% capacitance retention after 5000 cycles. When configured as an asymmetric supercapacitor (3DG/NiCo2O4//AC) for energy storage applications, the device delivers an impressive energy density of 16.35 Wh/kg at a power density of 749.81 W/kg, while maintaining 85.63% capacity retention after 6000 cycles. These results highlight the crucial role of nanoscale structural engineering in developing advanced energy storage materials.