Construction of MOF-derived Vanadium Nitride Decorated Micro/mesoporous Carbon Nanofibers for Aqueous Zinc-Ion Batteries.

Design and manufacture of cathode materials, with suitable pore structure and high electrical conductivity to matching zinc anode, solving the problem of dissolution and structural degradation of cathode materials for zinc ion batteries (ZIBs), is great significance to the development of ZIBs. Herein, Vanadium Nitride (VN) uniformly decorated N-doped micro/mesoporous carbon nanofibers (VN/N-MCNF) with appropriate porous and reactive sites for Zn2+ is prepared by using V-MOF, as important precursor via electrostatic spinning and pyrolysis technique. As a cathode electrode for ZIBs, the VN/N-MCNF is suitable for diffusion and adsorption of large-sized solvated structured [Zn(H2O)6]2+, for its abundant micro/mesoporous structure and good electrical conductivity. The VN/N-MCNF electrode has high specific capacity of 242 mAh g-1 at 0.1 A g-1 and rate performance. Moreover, the VN/N-MCNF-based ZIBs can reach 92.5% capacity retention after 200 cycles at a low current density of 0.3 A g-1, and can reach 86.1% capacity retention after 5000 cycles at a high current density of 5 A g-1. These findings highlight the importance of a rational design of cathode materials for high-performance metal batteries, which can also be extended to the design of other materials.