Fabrication of nickel ferrite@MWCNTs for super-capacitor applications

Nickel ferrites have served as electrode materials in energy storage applications such as batteries and supercapacitors in comparison to other metal oxides, they have a higher theoretical capacitance range. Pristine metal oxides are poor candidates as electrode components in electrochemical applications because of their tendency to aggregate and their less specific surface areas. Herein, we reported wet impregnation method to incorporate Nickel Ferrite (NiFe₂O₄) to multiwalled carbon nanotubes (MWCNTs) for improved electrochemical performance of nickel ferrites (NiFe₂O₄). The synthesized materials attained good crystallinity confirmed by X-ray diffraction (XRD). NiFe₂O₄ nanoparticle adhesions on multiwalled carbon nanotubes have been confirmed by scanning electron microscopy (SEM). UV-DRS was used to measure the bandgap for optical studies. Cyclic Voltammetry (CV), Galvanostatic Charge/Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) investigations for supercapacitor applications revealed that synthesized materials demonstrated good electrochemical potential, but MWCNTs supported NiFe₂O₄ composite attained exceptionally high specific capacitance (CV: 830 F g⁻¹ at 5 mV s⁻¹, GCD:343 F g⁻¹ at current density of 0.1 A g⁻¹) with capacitance retention of 98% at the current density of 0.8 A g⁻¹ after 3500 stability cycles.