Hydrothermally Engineered Ni, Zn (Fe2O4) Spinel Ferrite Nanostructures: for High-Energy Supercapacitors

Abstract

The work report here involves synthesis of Ni–Zn spinel ferrite nanoparticles for potential energy storage in supercapacitors. The structural and morphological analysis reveals that the highly crystalline phases exhibit average crystallite sizes of 41.8 nm (nickel ferrite) and 35.9 nm (zinc ferrite). The spinel ferrites' structure is further validated through FT-IR and Raman spectroscopic analyses. Field-emission SEM demonstrates a porous morphology, whereas EDS confirms the elemental composition. XPS analysis is confirming the binding energy of each element. BET results confirm a high specific surface area of synthesized material, ranging from 28.04 to 31.83 m²/g. Electrochemical studies of nickel ferrite and zinc ferrite nanoparticles were performed in a 3 M KCL electrolyte. Among the investigated electrodes, the symmetric devices delivered specific capacitances of nickel ferrite (NF) and zinc ferrite (ZF) of 81.7 F/g and 243.3 F/g @ lower current density of 0.9 A/g, respectively. Moreover, the ZF electrodes demonstrate a significantly higher energy density (27.37 Wh/kg) compared to NF (9.19 Wh/kg), while maintaining nearly identical power densities (~405 W/kg) at 0.9A/g. The NF//ZF asymmetric supercapacitor demonstrates excellent electrochemical performance, achieving 385.67 F/g specific capacitance, accompanied by a 53.56 Wh/kg energy density and a power density of 399.95 W/kg, all measured at 0.8 A/g.