Bionic Bone Structure Anode Material of High-Capacity 3D Porous Vanadium Nitride@Carbon Nanocomposite via Spray Phase Inversion.

Abstract

Vanadium nitride is expected to address the energy density challenge of supercapacitors due to its excellent performance; however, its poor cycle life and rate performance limit its application potential. Compounding vanadium nitride with carbon materials can be a good solution, but a well-designed composite structure is required to fully exhibit the electrochemical properties. In this study, porous carbon composites embedded with vanadium nitride nanoparticles are constructed by a spray phase-inversion strategy. The composites have a mesh structure, which similar to cancellous bone, and exhibit good electrochemical performance as a supercapacitor anode material: the specific capacity reaches 431.5 F g^-1 at the current density of 0.5 A g^-1, and capacity retentions of 78.7% after 5000 cycles in a 6 M KOH electrolyte solution. The good performance is attributed to the fact that the carbon skeleton provides an efficient channel for the transfer of electrons and ions, and the vanadium nitride nanoparticles are effective in increasing the capacity while being well confined by the carbon skeleton. The porous structural composites are versatile and may have good potential for applications in other energy conversion and energy storage systems.