Structural, electro-chemical and conduction mechanism in spinel NiFe2O4/NFO supercapacitor electrode material

Abstract

In the present work we have synthesized spinel nickel ferrite (NiFe2O4/NFO) nanoparticles by hydrothermal route using urea as basic medium. The prepared material was structurally characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy and Transmission electron microscopy (TEM). The structural analysis result clears that formation of single-phase nano structure of NFO system with particle size ∼23 nm. The electrical properties were examined in terms of impedance, relaxation mechanism and activation energy. Simultaneously the conductivity spectrum was analyzed in terms of hopping mechanism. Due to the increase of frequency exponent (n) with respect to temperature, the results are discussed using non overlapping small polaron tunneling (NSPT) model. In addition, NFO nanoparticle exhibits noble electrochemical behavior through a specific capacitance value of 560 Fg-1 in 3 M solution. The estimated optical band gap energy from the UV–visible spectrum for direct transition (n = 2) is found to be 2.5eV. In brief the present work gives useful guidance for preparing the NFO sample for energy storage and multifunctional device applications.