Bimetallic ZnFe₂O₄ nanosheets prepared via electrodeposition as binder-free high-performance supercapacitor electrodes

Binder-free bimetallic ZnFe₂O₄ nanosheets were fabricated using one-step electrodeposition, which facilitated excellent electrical contact between the ZnFe₂O₄ nanosheets and the nickel substrate. The resultant numerous ZnFe₂O₄ nanosheets with their cubic spinel structures promote interfacial activity to enhance the electrochemical and Faradaic redox reactions. The metallic Zn and Fe from the cubic spinel structure of ZnFe₂O₄ attract electrolytic ions and increase the energy-storage capability, thus yielding a specific capacitance of 1093 F·g ⁻¹ at a current rate of 1 A·g⁻¹. Different samples were prepared by varying the amount of metal salts in the electrodeposition solution while maintaining a constant ZnNt:FeSO₄ concentration ratio of 1:2 for all cases. The optimal electrode composition, which yielded an energy density of 54 Wh·kg⁻¹ and a capacitance retention of 93.5% at N = 5000 charge-discharge cycles, was identified.