Enhanced electrochemical performance and cycling stability of cadmium-doped copper vanadate electrodes for supercapacitor applications

Supercapacitors are promising energy storage devices owing to their high power density, rapid charge–discharge capability, and long cycle life. However, the moderate cycling stability of copper vanadate electrodes limits their practical application. In this work, cadmium-doped copper vanadate nanostructures are synthesized via a cost-effective co-precipitation method with varying Cd contents (1 %, 3 %, 5 %, and 7 %). Structural and morphological studies confirm the successful incorporation of Cd, which modifies the crystallite size, lattice strain, and surface features. Electrochemical analyses (CV, GCD, and EIS) demonstrate that Cd doping significantly enhances charge storage and charge transfer kinetics. Among all samples, the 5 % Cd-doped electrode exhibits the highest specific capacitance of 576 F/g at 5 mV/s and superior stability with 92.2 % retention after 3000 cycles. These findings highlight cadmium doping as an effective strategy to improve the pseudocapacitive behavior and long-term performance of copper vanadate electrodes, making them attractive candidates for next-generation supercapacitor applications.