Electrochemical investigation of magnetite-carbon nanocomposite in situ grown on nickel foam as a high-performance binderless pseudocapacitor

Magnetite-carbon nanocomposite was grown in situ on nickel foam by a novel auto-combustion method, and it was investigated for application as a pseudocapacitor electrode. Scanning electron microscopy (SEM) images of the magnetite-carbon (Fe3O4-C/Ni) show a sphere-like morphology with a diameter of 50 nm, and the amount of carbon in the nanocomposite was calculated 12.6% based on the thermogravimetric analysis (TGA). Infrared analysis indicates an in situ coating of the Fe3O4 nanospheres by carbon-oxygen moieties. The electrochemical behavior of the nanocomposite was studied in a wide potential window of 0 to − 1.2 V in 3 M KOH solution. The effect of a potential scan rate on the voltammetric currents shows a capacitive-dominant charge storage mechanism due probably to abundant electroactive sites on the electrode surface. A high specific capacitance of 300 F g−1 at 1 A g−1 in a wide potential window from 0 to − 1.2 V was achieved. The cycling stability studies were carried out in two different potential windows over 1000 CV cycles, and the nanocomposite showed a capacitance retention of 73% over 1 V. The pseudocapacitive performance observed here is superior to most of the magnetite-based pseudocapacitors reported to date.