Plasma-Assisted Fluorine Doping of Graphene Oxide for High Performance Supercapacitors

Abstract

Carbon-based materials are considered to be promising cadidates for energy storage systems because of their superior conductivity, low price, and high specific surface area. Moreover, heteroatom-doped graphene or graphitic carbons are prepared by various methods for modulating their physicochemical properties, improving their wettabililty, and achieving favorable pseudocapacity for use in electrochemical supercapacitors. Here we report a simple solvent-free scale-up technique to synthesis fluorine-doped graphene oxide (FGO) by direct plasma treatment of graphene oxide (GO) powder at ambient pressure. The FGO enabled fast electrochemical charge transfer and provided a large number of active sites for redox reactions during supercapacitor operation, and the mechanisms were thoroughly studied by various electrochemical analyses. As a result, fabricated symmetric supercapacitor using FGO electrodes exhibited a maximum power density (~3200 W/kg) and energy density (~25.87 Wh/kg) with superior cycle stability (20000 cycles) without capacitance loss. Furthermore, the computational calculation results clarified the roles of semi-ionic C–F bonding of FGO: huge charge accumulation on the electrodes and superior electrical conductivity. Thus, our study demonstrates a facile strategy to develop promising functionalized materials, which can enhance the viability of supercapacitor for the next generation of energy storage systems.