<p>Cobalt oxides (Co₃O₄) decorated on bismuth vanadate (BiVO₄) via the co-precipitation method exhibit significant potential for supercapacitor applications. This synthesis enables controlled nucleation and uniform growth of Co₃O₄–BiVO₄ nanostructures, enhancing the morphology of electrode and electrochemical performance. We characterized the structural and morphological properties of the nanocomposite and evaluated its electrochemical performance in 1&#xa0;M KOH aqueous solution. The Co₃O₄–BiVO₄ nanocomposite demonstrated a specific capacitance of 726 F g⁻¹ at a current density of 1 A g⁻¹. Furthermore, an asymmetric solid-state device integrating the nanocomposite with activated carbon (AC) retained 86% of its initial capacitance over 2500 charge–discharge cycles at a current density of 2 A g⁻¹, demonstrating excellent stability. Overall, our findings suggest that the Co₃O₄–BiVO₄ nanocomposite holds promise as an electrode material for supercapacitor applications, offering high specific capacitance, longevity, and noteworthy energy and power density. These results also highlight the potential scalability of this facile synthesis approach for practical supercapacitor devices.</p>