Abstract
Supercapacitors have the characteristics of high specific capacitance, long cycle life and fast charging ability, which have shown extremely valuable applications in energy storage fields. Improving the electrode materials is a crucial approach to achieve high capacity. Vanadium nitride (VN) has higher theoretical capacitance than noble metal oxides, as well as better chemical stability and good electrical conductivity. Herein, a composite of VN nanowires with multiple cavities encapsulated in N-doped reduced graphene oxide lamellar layers (VNNWs@rGO) has been synthesized by facile freeze-casting and subsequent nitridation technique. The hierarchical VNNWs@rGO composite exhibited excellent supercapacitor performance: high capacitances of 222 and 65 F g−1 were achieved at current densities of 0.5 and 10 A g−1, respectively. The improved electrochemical performance is associated with the unique structural design: the N-doped rGO sheets endowed enhanced electric conductivity and chemical stability for VN, the interconnected laminar network of VNNWs@rGO are crucial for electrolyte penetration and charge transfer, and the cavities and nanoparticles inside the VN nanowires can provide abundant active sites for electric double-layer capacitor and pseudocapacitance.
Highlights
Developing efficient electrochemical energy storage materials and devices is crucial to developing renewable new energy system
Nanocarved Vanadium nitride (VN) nanowires were transformed from intact V2O5 nanowires, and VNNWs@rGO sheets were obtained from VONW@graphene oxide (GO) by heat treatment under NH3 flow at a certain rate
VNNWs@rGO sample that prepared with 2 M and 4 M GO suspension are donated as VNNWs@rGO-2, and VNNWs@rGO-4, respectively
Summary
Developing efficient electrochemical energy storage materials and devices is crucial to developing renewable new energy system. As a type of electric energy storage device, the characteristic of a supercapacitor is between the secondary battery and traditional dielectric capacitor[1,2,3,4]. Compared with carbon electrode materials, transition metal nitrides have higher mass capacity and vibrational density, and exhibit greater volume energy density[7, 8]. The application of transition metal nitrides in electrochemical energy storage field still has the following problem: exhibit high capacity, transition metal nitrides is a typical ceramic material with nonnegligible brittleness, which inhibited its structural stability during long-term cycling process of a supercapacitor device[23]. Possible underlying mechanisms for the promising electrochemical performance were discussed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
