Electrodeposited Cu–GO/PANI Hybrid with Enhanced Charge Transport and Pseudocapacitive Synergy for High-Performance Supercapacitors

The development of electrode materials that combine high capacitance, rapid charge transport, and structural stability remains a central challenge in advancing supercapacitor technology. In this study a ternary nanocomposite copper-doped graphene oxide/polyaniline (Cu–GO/PANI) engineered via novel electrodeposition approach to exploit the synergistic interaction between conducting polymers, two-dimensional carbons, and transition-metal nanoparticles. Structural characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area analysis, and field emission scanning electron microscopy coupled with energy-dispersive spectroscopy (FESEM-EDS) confirmed the successful integration of copper nanoparticles within the GO/PANI framework. Electrochemical performance was systematically evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The Cu–GO/PANI electrode exhibited a significantly enhanced charge storage capability, achieving a specific capacitance of 1953 F·g⁻¹ at 1 A·g⁻¹, with an energy density of 43.4 Wh·kg⁻¹. The superior performance was attributed to copper-induced doping effects, synergistic interactions between PANI and GO nanosheets, and improved charge-transfer pathways that reduced internal resistance. Although capacitance retention decreased to 53% after 200 cycles, the study demonstrates the effectiveness of this novel synthesis strategy in producing metal–polymer–graphene hybrids. These findings highlight the potential of Cu–GO/PANI as a promising electrode platform for next-generation supercapacitors with high energy and power densities.