Improved charge storage kinetics using metal carbide integrated NiO hybrid composite electrodes for supercapacitors

The intrinsic meagre storage kinetics and electrical conductivity of transition metal oxides are posing significant obstacles to their exploration as electrode materials for supercapacitor applications. The hybridization of transition metal oxides with metal carbides (Mo₂C and W₂C) have shown as the promising approach for the electrode fabrication which offered enhancing electrical conductivity, specific surface area, and high porosity in the resulting nanocomposites. Hence, herein, we produced the NiO-Mo₂C and NiO-W₂C nanocomposite electrode materials by the hydrothermal process. The prepared NiO-Mo₂C and NiO-W₂C electrode materials exhibited improved specific capacitance, reaching 604 and 592 F g⁻¹ at 0.5 A g⁻¹, respectively. Additionally, these materials demonstrated superior cycling stability, maintaining 96.5 % and 97.8 % of their initial capacitance even after 3000 cycles at a current density of 3 A g⁻¹. Moreover, an asymmetric supercapacitor (ASCs) was fabricated with (NiO-Mo₂C and NiO-W₂C) as the positive and activated carbon (AC) as the negative electrode which exhibited enriched energy density of 37 and 34 Wh kg⁻¹ at a power density of 2.4 kW kg⁻¹ compared with pristine structures. Importantly, the illumination of light-emitting diodes (LEDs) by couple of connected ASCs authorized the prepared NiO-Mo₂C and NiO-W₂C materials' significant potential for practical applications.