Construction of novel nanocomposite ZnO@CoFe2O4 microspheres grown on nickel foam for high performance electrochemical supercapacitors

Novel ZnO@CoFe2O4 and CoFe2O4 nanocomposites have potential applications on account of their high surface area and electrical properties. These two nanocomposite electrodes on nickel foam were developed for high performance electrochemical supercapacitor applications using a low-cost and facile one-step hydrothermal approach. The surface morphologies and electrochemical properties of the ZnO@CoFe2O4 and CoFe2O4 nanocomposites were examined by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. The electrochemical tests indicated that the ZnO@CoFe2O4 nanocomposite electrode achieved a high specific capacitance of 4050.4 F g(-1) at 10 mA cm(-2) with a high energy density of 77.01 W h kg(-1) in a 3 M KOH aqueous solution. This electrode exhibited attractive cycling stability and specific capacitance with approximately 90.9% capacity retention after 1000 cycles. On the other hand, the CoFe2O4 electrode showed lower specific capacitance (3499.9 F g(-1)) and cycling stability (50.07%) than the ZnO@CoFe2O4 nanocomposite electrode. These results highlight the potential of these ZnO@CoFe2O4 nanocomposite electrodes as electrodes for next generation supercapacitor applications in high energy density storage systems.