Fe₃O₄@Carbon Nanosheets for All-Solid-State Supercapacitor\nElectrodes

Abstract

Fe₃O₄@carbon\nnanosheet composites were synthesized using ammonium ferric citrate\nas the Fe₃O₄/carbon precursor and graphene oxide\nas the structure-directing agent under a hydrothermal process. The\nsurface chemical compositions, pore structures, and morphology of\nthe composite were analyzed and characterized by nitrogen adsorption\nisotherms, TG analysis, FT-IR, X-ray photoelectron energy spectrum,\ntransmission electron microscopy, and scanning electron microscopy.\nThe composites showed excellent specific capacitance of 586 F/g, 340\nF/g at 0.5 A/g and 10 A/g. The all-solid-state asymmetric supercapacitor\ndevice assembled using carbon nanosheets in situ embedded Fe₃O₄ composite and porous carbon showed a largest energy\ndensity of 18.3 Wh/kg at power density of 351 W/kg in KOH/PVA gel\nelectrolyte. The synergism of high special surface to volume ratio,\nmesoporous structure, graphene-based conduction paths, and Fe₃O₄ nanoparticles provided a high surface area of\nion-accessibility, high electric conductivity, and the utmost utilization\nof Fe₃O₄ and resulted in excellent specific\ncapacitance, outstanding rate capability and cycling life as all-solid-state\nsupercapacitor electrodes.