Deposition of Fe3O4 on oxidized activated carbon by hydrazine reducing method for high performance supercapacitor

Oxidized activated carbon/Fe3O4 (AC/Fe3O4) composites for supercapacitor electrodes were synthesized by a reduction method. Poly(vinylpyrrolidone) was added as a dispersing agent for homogeneous deposition of Fe3O4 on AC. The obtained products were identified as AC/Fe3O4 by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. Morphological characterization of AC/Fe3O4 was carried out by field emission scanning electron microscopy (FE-SEM); the results clearly showed the formation of Fe3O4 nanoparticles about 30 nm in diameter on AC. Moreover, by using N2 adsorption/desorption isotherm analysis, we confirmed that surface areas and pore volumes decreased with increasing Fe3O4 content. We also carried out electrochemical characterization of AC and AC/Fe3O4 composites. Remarkably, we found that the value of specific capacitance increased significantly from 99.4 F g−1 of raw AC to 202.6 F g−1 of AC/Fe3O4 composites at 10 mV s−1 of scan rate. This result can be ascribed to a synergistic effect of the combination of electrical double-layer capacitance and pseudo-capacitance properties. This research represents a valuable contribution to the application of supercapacitor electrodes in regard to cost effectiveness and simple fabrication.