NiSe ₂ @CdO Nanocomposite: A Next‐Generation Electrode for Asymmetric Supercapacitors with Gel Electrolyte

This article investigates the electrochemical performance of NiSe 2 @CdO nanocomposites synthesized by combining melt‐diffusion‐synthesized NiSe 2 and hydrothermally prepared CdO, followed by ball milling to obtain the final NiSe 2 @CdO composite. Structural, morphological, and electrochemical analyses revealed flake‐like NiSe 2 nanoparticles decorated with rod‐shaped CdO nanostructures, exhibiting exceptional electrochemical performance. The nanocomposite electrode achieved a specific capacitance of 255 F/g at 10 mV/s from the three‐electrode setup, and also, was achieved at an energy density of 48 Wh/kg at the power density 2000 W/kg by the NiSe 2 @CdO||AC asymmetric device. fourier transform infrared analysis confirmed the structural integrity, while transmission electron microscopy images revealed nanostructures with clear lattice fringes, and energy‐dispersive X‐ray Spectroscopy verified elemental uniformity. The device demonstrated 96.7% capacitance retention even after 5000 cycles and displayed superior energy and power density characteristics in the Ragone plot. These results in turn, highlight the potential of NiSe 2 @CdO nanocomposites for next‐generation energy storage systems.