Flexible free-standing graphene-like film electrode for supercapacitors by electrophoretic deposition and electrochemical reduction
(1. Key Laboratory of Energy Resources and Chemical Engineering, Department of Chemical Science and Engineering,
Ningxia University, Yinchuan 750021, China;
2. Key Laboratory of Ningxia for Photovoltaic Materials, Ningxia University, Yinchuan 750021, China)
Ningxia University, Yinchuan 750021, China;
2. Key Laboratory of Ningxia for Photovoltaic Materials, Ningxia University, Yinchuan 750021, China)
Abstract: Electrophoretic deposition in conjunction with electrochemical reduction was used to make flexible free-standing graphene-like films. Firstly, graphene oxide (GO) film was deposited on graphite substrate by electrophoretic deposition method, and then reduced by subsequent electrochemical reduction of GO to obtain reduced GO (ERGO) film with high electrochemical performance. The morphology, structure and electrochemical performance of the prepared graphene-like film were confirmed by SEM, XRD and FT-IR. These unique materials were found to provide high specific capacitance and good cycling stability. The high specific capacitance of 254 F/g was obtained from cyclic voltammetry measurement at a scan rate of 10 mV/s. When the current density increased to 83.3 A/g, the specific capacitance values still remained 132 F/g. Meanwhile, the high powder density of 39.1 kW/kg was measured at energy density of 11.8 W•h/kg in 1 mol/L H2SO4 solution. Furthermore, at a constant scan rate of 50 mV/s, 97.02% of its capacitance was retained for 1000 cycles. These promising results were attributed to the unique assembly structure of graphene film and low contact resistance, which indicated their potential application to electrochemical capacitors.
Key words: free-standing graphene-like film; supercapacitor; electrophoretic deposition; electrochemical reduction; flexibility