A facile method to synthesize FexCy/C composite as negative electrode with high capacitance for supercapacitor

The FexCy/C composite as negative electrode for supercapacitor has been prepared facilely through one-step solid state reaction. The SEM images show that the FexCy exhibits polyhedron shape with average size of 50 nm and distributes randomly on the wire-like carbon substrate. The XRD patterns reveal that the FexCy is composed of Fe1.88C0.12 and Fe15.1C. The electrochemical results demonstrate that the as-prepared product exhibits enlarged specific capacitance (274.68 F/g at a current density of 2.5 A/g), which is almost four times as high as that of carbon (79 F/g) and higher than those of other Fe-based materials. Furthermore, its low charge-transfer resistance is 0.12 Ω. The capacitance can remain 95.24% of its initial capacitance at a high current density of 30 A/g after 1000 cycles. From the results above, we can conclude that the obtained FexCy/C is a promising negative electrode material for supercapacitor.