Graphene/ZnO Hybrid Nanocomposites Electrode Material for High-Performance Supercapacitor Application

Through ex situ synthesis, a graphene-zinc oxide nanocomposite system has been assembled. The ZnO nanoparticle concentration in this system was adjusted at intervals of 5% in a given amount of graphene. The ZnO mean crystallite size was determined using the Debye–Scherrer formula and was found to be 19.26 nm. This work illustrates how the supercapacitive characteristics of graphene-ZnO nanocomposites were optimized. An electrolyte (3 M KOH) was used in the electrochemical investigations. The addition of ZnO nanoparticles affected the supercapacitive properties of graphene, as predicted, and it was optimal for a ZnO concentration of 20 wt.%. Specific capacitance of 278.30 F g⁻¹ at a scan rate of 20 mV s⁻¹ was demonstrated by the 20 wt.% graphene-ZnO nanocomposites. The material maintained high capacity retention (~94.78%) after 2000 cycles. Similarly, the galvanostatic charge/discharge curves of the graphene-ZnO nanocomposite exhibit lengthy, almost symmetric behavior that makes them appropriate for a variety of real-world uses.