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

Abstract

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.