Synthesis and investigations of structural, surface morphology, electrochemical, and electrical properties of NiFe2O4 nanoparticles for usage in supercapacitors

This article reports the synthesis of NiFe₂O₄ nano-ferrites in form of nanoparticles and investigating their various properties such as structural, surface morphology, electrocehmical and electrical properties with the help of a variety of characterization techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), cyclic-voltammetry, and impedance analyzer. The NiFe₂O₄ nanoparticles were synthesized via sol–gel route for the suitable application in making the energy storage devices like supercapacitors. Structural analysis was performed by XRD for determining the crystalline size and micro-strain produced in the sample via study of W–H plot. The average crystalline size was found ~ 40 nm and the micro-strain was determined as ~ (− 0.00346) corresponding to negative intercept in W–H plot. The negative micro-strain confirms the presence of compressive micro-strain in the sample. The FESEM was used for analysis of surface morphology which confirms the size of nanoparticles. For understanding the super-capacitive behavior of the synthesized samples, recording of cyclic-voltammetry data for the prepared sample was performed at the scan frequency 10, 20, 50, and 100 mV/s. The maximum area is covered at the 100 mV/s scan rate with maximum specific capacitance of ~ 200 F/g. The highest contribution of active ions is seen at lower scan rates during the redox reaction and vice versa. For electrical characteristics (dielectric constant, dielectric loss, ac conductivity, and impedance), the impedance analyzer was utilized. These all studies suggest that the nano-ferrites like NiFe₂O₄ nano-particles are very important materials which show low loss at very high frequency and thus these materials can be recommended for high frequency supercapacitor applications.