An Eco-Friendly Nitrogen Source for the Preparation of Vanadium Nitride/Nitrogen-Doped Carbon Nanocomposites for Supercapacitors

It is highly urgent to find an eco-friendly nitrogen source for the preparation of metal nitrides as an electrode material for supercapacitors (SCs). Herein, vanadium nitride/N-doped carbon (VN/NC) nanocomposites were prepared from the nitrogen source of g-C3N4 by a facile one-step annealing process. VN NPs, with an average particle size of 7 nm, make an important contribution to the capacitance of the composites. N-doped carbon (NC), with an advanced sheet-like structure and high nitrogen content provides a large surface area and effective electrolyte penetration, leading to more exposed VN active sites and a good electrical conductivity. As a supporting substrate, NC nanosheets (NCS) prevent VN NPs from aggregation, thereby a favorable cycling stability of the composite electrode was achieved. In addition, as the (-) 0.04-VN/NCS2//NiCo2S4 (+) asymmetric device is assembled, favorable specific capacitance, high energy, and power density can also be obtained.