Performance enhancement of supercapacitors using zinc oxide/reduced graphene oxide nanocomposites and Nafion-117 based hybrid electrolytes

Abstract This study presents a cost-effective strategy to enhance supercapacitor performance using ZnO/reduced graphene oxide (ZnO/rGO) nanocomposites synthesized via a microwave-assisted method. The nanocomposites exhibit pseudocapacitive behavior, enabling improved charge storage. A PVA/KOH gel polymer electrolyte and a Nafion-117 film were integrated to enhance ionic conductivity and structural stability. Structural and morphological characterizations (XRD, FTIR, SEM, and TGA) confirmed the successful formation of uniformly distributed ZnO nanoparticles (average size: 22.44 ± 0.09 nm) on rGO sheets. Electrochemical testing revealed a high specific capacitance of 812.23 F·g⁻ 1 , an energy density of 28.20 Wh·kg⁻ 1 , and a power density of 4,060.80 W·kg⁻ 1 . Moreover, the composite retained 99.97% of its capacitance after 5,000 cycles. These results demonstrate the potential of ZnO/rGO–Nafion hybrid electrodes for next-generation high-performance supercapacitors.