CuO-doped bismuth cobalt oxyhydroxide (CuO–BiCoOOH) nanostructures were successfully synthesized via a hydrothermal route. The obtained samples were characterized using XRD and FT-IR analyses and subsequently employed for electrode fabrication in supercapacitor applications. The engineered morphology provides electrochemically active sites, enabling efficient charge transfer and storage. The fabricated electrode delivered a specific capacitance of 300 F g⁻¹ at 1 A g⁻¹ in 1 M KOH electrolyte, along with stable cycling performance. These findings indicate that CuO doping in BiCoOOH frameworks can tune electrochemical behavior, offering a pathway toward reliable energy storage devices