Gold nanoparticles decorated rGO-ZnCo2O4 nanocomposite: A promising positive electrode for high performance hybrid supercapacitors

Abstract

Herein, we have engineered gold nanoparticles decorated reduced graphene oxide-ZnCo2O4 hybrid material by a hydrothermal process. With exercising benefit of a synergistic influence of reduced graphene oxide and gold nanoparticles, the nanohybrid ensures that internal microstructure is altered from ZnCo2O4 microflower to Au@rGO-ZnCo2O4 cauliflower. The prepared Au@rGO-ZnCo2O4 cauliflower electrode shows a high specific capacity of 288.5 mAh g−1 at 2 mV s−1 scan rate. The more detailed electrochemical interpretation is carried out to understand the charge storage abilities of the electrodes occurred from the capacitive- and diffusion-controlled kinetics processes. These excellent electrochemical performances can be assigned to the incorporation of gold nanoparticles and reduced graphene oxide nanosheets that alleviate electrons exchange and transmit through electrochemical active sites, which create an electronic and structural heterogeneity of the electro-active material. Further, Au@rGO-ZnCo2O4//AC hybrid solid-state supercapacitor cell is designed with polymeric gel electrolyte that delivered a good power density of 2121 W kg−1 at an energy density of 31 Wh kg−1 with excellent capacitance retention over 5000 cycles highlights convenience of the utility of mixing high capacity with high electronic transport. The experimental results reveal that the noble metal nanoparticles incorporated hybrid nanostructures are promising electrode materials for energy storage applications.