Study of magneto-supercapacitance properties of nickel cobalt ferrite-activated carbon composite

Ni0.5Co0.5Fe2O4-Activated Carbon (NCFO-AC) composite was synthesized and studied for its super-capacitance under the influence of an external magnetic field. The magnetic nickel cobalt inverse spinel ferrite was prepared via a conventional sol-gel synthesis route. The high surface area activated carbon was synthesized from mushrooms' spent substrate using the green microwave technique. A simple physical mixing was used to obtain the NCFO-AC composite material. The structural analysis using XRD confirmed the formation of the composite corroborating the findings of Raman spectroscopy. The accommodation of NCFO nanoparticles on the porous carbon base was verified by analysing the morphology of NCFO-AC composite using SEM. The stoichiometric ratio of all the elements present in the composite material was confirmed by EDX spectra. The magnetic studies at room temperature revealed the soft ferromagnetic nature of NCFO and reduction in magnetization on the addition of carbon (NCFO-AC). The composite material exhibited a specific capacitance of 1790.9 F/g at a scan rate of 1 mV/s. The composite exhibited a near doubling of the specific capacity from 574.9 F/g to 1242.5 F/g under the influence of the magnetic field of 4000 G at a scan rate of 50 mV/s. The composite showed capacitance retention of 98.34% after 10,000 cycles demonstrating high stability.