Chemical reduction-induced defect-rich and synergistic effects of reduced graphene oxide based Cu-doped NiO nanocomposite (RGO@Cu-NiO NCs) decorated on woven carbon fiber for supercapacitor device and their charge storage mechanism

In today's technological landscape, energy storage devices such as batteries and supercapacitors play a critical role, with hybrid variants attracting significant attention. This study focuses on synthesizing a ternary nanocomposite material composed of reduced graphene oxide adorned Cu-doped NiO (RGO@Cu-NiO NC) for high-performance supercapacitor device applications. Unlike most research that analyzes NiO-based nanocomposites in alkaline electrolytes, our study explores RGO@Cu-NiO NCs coated on woven carbon fiber in Na₂SO₄ electrolyte, revealing a more dominant surface reaction mechanism. Electrochemical analysis unveiled that the specific capacitances of RGO@Cu-NiO NCs surpass those of Cu-doped NiO NPs by 1.14 times and those of pristine NiO nanoparticles (NPs) by 1.28 times, showcasing a remarkable enhancement in performance. Additionally, the study investigated the charge storage mechanism, providing intriguing insights into the capacity contribution from RGO@Cu-NiO NC to the overall capacitance. The outstanding performance of RGO@Cu-NiO NCs is attributed to incorporating RGO sheets and enhancing charge-storage capacity through facilitated conductive networks. Impressively, the material retained 94 % capacity even after 10,000 cycles. Furthermore, a symmetric supercapacitor device (SSD) based on RGO@Cu-NiO NCs demonstrated a notable specific capacitance of 261.25 F/g at 1.5 A/g, along with 43.54 Wh/kg energy density at 750 W/kg power density, and retained ~96 % capacitance after 10,000 cycles. These findings establish RGO@Cu-NiO nanocomposites as auspicious materials for advanced supercapacitor applications.