Superior volumetric capacitance of nitrogen and fluorine Co-doped holey graphene/PANI composite film for supercapacitor electrodes

For the development of small portable energy storage devices with limited space, high volumetric capacitance which representing the chance of reducing the volume is becoming the most critical factor to the real industrial applications. Herein, we introduce a novel simple strategy to fabricate a free-standing binder-free N and F co-doped holey graphene/PANI (NFHG/PANI) composite film, in which the doping of nitrogen and fluorine in holey graphene nanosheets boosts the electron transfer efficiency and facilitates the polymerization and growth of aniline on the graphene surface in the form of nanoparticles. The NFHG/PANI performed a gravimetric capacitance of 580 F g(-1) at a current density of 0.5 A g(-1) and long-term cycling stability, more importantly, it delivered 828 F cm(-3) superior volumetric capacitance at a high packing density. Apparently, such a free-standing NFHG/PANI composite film with excellent performance is of great significance for the development of miniaturized portable energy storage devices.