Construction of MWCNT nanoneedles decorated on NiCo2O4/MnO2 composite electrodes with high energy density for asymmetric capacitor applications

Abstract

In this work, a nanocomposite electrode of MWCNT nanoneedles decorated on spheres like NiCo2O4/MnO2 on NF is designed by a hydrothermal method and ultrasonication technique. The resulting interconnected network has an open geometric structure and a porous nature. Furthermore, NiCo2O4/MnO2@MWCNT's greater surface area (174.2 m2/g) promoted ion diffusion and transport, which enhanced specific capacitance. Consequently, this hybrid composite demonstrates a remarkable specific capacitance of 1728 F/g at 1 A/g, in addition to outstanding durability, maintaining 93.83 % of its capacitance after 10,000 cycles. A NiCo2O4/MnO2/MWCNT hybrid composite is used as the positive electrode, while Activated carbon serves as the negative electrode in an asymmetric supercapacitor. This configuration achieves an energy density of 55.8 Wh kg−1 and a maximum power density of 4099 W kg−1. This outcome indicates that the NiCo2O4/MnO2/MWCNT hybrid composite shows promise as highly efficient electrodes in energy storage devices.