<p>In this study, we aimed to develop a novel electrode material for hybrid supercapacitors by synthesizing NiO@Sb₂Se₃ nanocomposites and evaluating their electrochemical performance. Antimony triselenide (Sb₂Se₃) nanoparticles were synthesized via a facile melt diffusion technique at 700&#xa0;°C, while nickel oxide (NiO) nanoparticles were prepared by a hydrothermal method. Both nanomaterials were composited through ball milling and characterized using SEM, PXRD, SAED, HRTEM, and XPS. Electrochemical studies demonstrated that the composite delivered a specific capacity of 140.26 Fg⁻¹ at 10 mVs⁻¹ and 128.97 Fg⁻¹ at 1 Ag⁻¹ in a three-electrode configuration. A hybrid supercapacitor device assembled with PVA–KOH gel electrolyte exhibited a wide potential window (0–2&#xa0;V), achieving 60.58 Cg⁻¹ at 1 Ag⁻¹, with an energy density of 33.65 Whkg⁻¹ at 2000 Wkg⁻¹, power density, and 82.3% capacity retention over 2000 cycles. These results demonstrate the potential of NiO@Sb₂Se₃ nanocomposites as promising electrode materials for next-generation energy storage devices.</p>