Synthesis, characterization, and supercapacitor applications of Ni-doped CuMnFeO4 nano Ferrite

Nickel (Ni) doped magnetically separable Cu1-xNixMn1.0Fe1.0O4 ferrite was synthesized using the sol-gel auto-combustion method. The system exhibits a cubic spinel structure with a single phase in all the samples, which was confirmed using Rietveld refinement. Mixed morphology with agglomerated particles with nearly spherical/multi-faceted shapes was observed in FESEM studies. The elemental composition was confirmed from EDAX analysis. TEM images are in well accordance with FESEM images and reveals the crystalline nature of the synthesized samples. Magnetic properties of all the ferrites were studied using VSM. With the increase in the concentration Ni2+ the Cu1-xNixMn1.0Fe1.0O4 ferrite transform from ferrimagnetic character to a superparamagnetic character. The as-synthesized materials were further tested for their electrochemical and supercapacitor applications. The electrochemical measurements revealed that Cu1-xNixMn1.0Fe1.0O4 with (x = 0.75) exhibits superior electrochemical performance over the other samples. The high specific capacitance of 975 F g−1, the high energy density of 20.8 Whkg−1 at a scan rate of 5 mVs-1, and 94.4% capacity retention over 5000 cycles were observed for Cu1-xNixMn1.0Fe1.0O4 with a concentration of x = 0.75.