Facile synthesis of vanadium nitride/nitrogen-doped graphene composite as stable high performance anode materials for supercapacitors

Novel vanadium nitride/nitrogen-doped graphene (VN/NG) composite was fabricated and used as stable high performance anode materials for supercapacitors. The VN/NG composite anode material exhibited excellent rate capability, outstanding cycling stability, and superior performance. FE-SEM and TEM studies of VN/NG composite revealed that ultra-thin VN nanostructures were homogeneously distributed on flexible NG nanosheets. The NG provided a highly conductive network to boost the charge transport involved during the capacitance generation and also aided the dispersion of nanostructured VN within the NG network. The synergetic VN/NG composite exhibited an ultra-high specific capacitance of 445 F g^-1 at 1 Ag^-1 with a wide operation window (-1.2 to 0 V) and showed outstanding rate capability (98.66% capacity retention after 10,000 cycles at 10 Ag^-1). The VN/NG electrode offered a maximum energy density (∼81.73 Wh kg^-1) and an ultra-high power density (∼28.82 kW kg^-1 at 51.24 Wh kg^-1). The cycling performance of the VN/NG composite was superior to that of pure VN nanostructure. These finding open a new path way to the designated fabrication of VN/NG composite as anode materials in the development of high performance energy storage devices.