Hydrothermal synthesis of NiCo2O4 and Typha angustifolia derived activated carbon composite: Physicochemical and electrochemical characterization for supercapacitor application

The growing global demand for clean and efficient energy storage solutions has accelerated research into advanced electrode materials for high-performance supercapacitors. In this study, NiCo 2 O 4 nanoparticles (NCOC), Typha angustifolia -derived activated carbon (TAC), and their composite (NCOC/TAC) were synthesized via a hydrothermal method coupled with chemical activation to develop a sustainable, high-efficiency electrode system. Structural and morphological analyses confirmed the successful formation of a highly porous composite architecture featuring uniformly distributed NiCo 2 O 4 nanoparticles anchored onto a conductive carbon framework. This engineered morphology provides abundant ion diffusion pathways, enhanced electrical conductivity, and a large number of accessible electroactive sites. Electrochemical evaluation demonstrated the superior performance of the NCOC/TAC electrode, which delivered significantly higher specific capacitance, reduced charge-transfer resistance, and improved ionic transport compared to the individual components. When assembled into an asymmetric supercapacitor (NCOC/TAC//TAC), the device achieved an impressive energy density of 86.39 Wh kg⁻ 1 at 500 W kg⁻ 1 power density and maintained 90.03% capacitance retention after 5000 cycles, highlighting exceptional rate capability and long-term stability. The synergistic integration of redox-active NiCo 2 O 4 with biomass-derived activated carbon underscores a promising strategy for developing environmentally friendly, high-performance energy storage devices. These findings establish the NCOC/TAC composite as a strong candidate for next-generation supercapacitors and provide valuable insight into designing sustainable electrode materials for advanced energy storage applications.