Electrode material for high performance symmetric supercapacitors based on superparamagnetic Fe₃O₄ nanoparticles modified with cetyltrimetylammonium bromide

A facile preparation method is reported to develop a supercapacitance material with high specific capacitance and stability. Fe₃O₄ superparamagnetic material was synthesised via CTAB assisted co-precipitation method to modify the morphology. Presence of CTAB has resulted in excellent output in terms of high specific capacitance of 1192 F/g at a current density of 1 A/g. 93% of charge storage capacity was retained by the working electrode after 4000 charge-discharge cycles with the optimum concentration of CTAB. The TEM micrograph showed a quasi-spherical morphology for the bare Fe₃O₄ and the same was modified to semi-cuboidal shape after CTAB modification. The change in crystal lattice was confirmed through SAED in parallel to the WAXRD analysis. The phase purity was deciphered using XPS and surface roughness of the electrode was studied using AFM. Increased saturation magnetisation value for CTAB modified Fe₃O₄ was also in line with the improved charge storage capacity.