Synthesis of carbon-coated Fe3O4 nanorods as electrode material for supercapacitor

Carbon-coated Fe3O4 and pure Fe3O4 nanorods are synthesized via hydrothermal reaction and subsequent sintering procedure. The as-prepared products characterized by X-ray diffraction and scanning electron microscopy analysis indicate that carbon coating does not affect the structure and morphology of Fe3O4. Transmission electron microscope shows that Fe3O4 nanorods are homogeneously coated by carbon layer with a thickness of approximately 2 nm. The electrochemical properties measured by cyclic voltammetry, galvanostatic charge–discharge cycling and electrochemical impedance spectroscopy tests show that carbon-coated Fe3O4 (Fe3O4/C) nanorods present improved electrochemical performance due to the carbon layer. A specific capacitance of 275.9 F g−1 is achieved at a current density of 0.5 A g−1 in 1 M Na2SO3 aqueous solution for the Fe3O4/C nanorods in comparison to that of 208.6 F g−1 for pure Fe3O4.