MnFe₂O₄ Nanoparticles as an Efficient Electrode for Energy Storage Applications

In this study, solvothermal method was used for the synthesis of MnFe₂O₄ nanoparticles at different processing period of 7, 14, and 21 h. X-ray diffraction (XRD) pattern study confirms that MnFe₂O₄ nanoparticles correspond to the face-centered cubic spinel structure and belong to the Fd3m [227] space group. From Raman spectra analysis, two major peaks were observed at 476 and 616 cm⁻¹, which correspond to the vibration modes of MnFe₂O₄ nanoparticles; especially, the broad peak at 620 cm⁻¹ (A1g) corresponds to the symmetric stretching vibration of oxygen atoms at tetrahedral site. Infrared spectra (FTIR) analysis at 490 and 572 cm⁻¹ can be attributed to the stretching vibration of tetrahedral groups of FeO₄, and the vibration of octahedral groups of FeO₆ belongs to the intrinsic vibrations of manganese ferrites. The uniformly distributed MnFe₂O₄ nanospheres (RT2) can be affirmed by field emission scanning electron microscopy images and confirmed by the high-resolution transmission electron microscopic studies. The electrochemical properties of synthesized MnFe₂O₄ nanoparticles investigated by cyclic voltammetry, impedance spectroscopy and galvanstatic charging and discharging (GCD) studies clearly predict the reversible faradaic reactions of MnFe₂O₄ nanospheres. Further, the MnFe₂O₄ nanospheres (RT2) exhibit high specific capacitance of 697 F g⁻¹ at 0.5 A g⁻¹ current density in galvanostatic charging and discharging profile and after 1000 cycles exhibits 79% retain ability of initial specific capacitance and hence can be considered as the efficient electrode for supercapacitor applications.