Superior lithium storage performance of hierarchical porous vanadium pentoxide nanofibers for lithium ion battery cathodes

Abstract

The hierarchical V2O5 nanofibers cathode materials with diameter of 200–400nm are successfully synthesized via an electrospinning followed by annealing. Powder X-ray diffraction (XRD) pattern confirms the formation of phase-pure product. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) obviously display the hierarchical porous nanofibers constructed by attached tiny vanadium oxide nanoplates. Electrochemical behavior of the as-prepared product is systematically studied using galvanostatic charge/discharge testing, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). It turns out that in comparison to the commercial V2O5 and other unique nanostructured materials in the literature, our V2O5 nanofibers show much enhanced lithium storage capacity, improved cyclic stability, and higher rate capability. After 100 cycles at a current density of 800mAg−1, the specific capacity of the V2O5 nanofibers retain 133.9mAhg−1, corresponding to high capacity retention of 96.05%. More importantly, the EIS at various discharge depths clearly reveal the kinetics process of the V2O5 cathode reaction with lithium. Based on our results, the possible approach to improve the specific capacity and rate capability of the V2O5 cathode material is proposed. It is expected that this study could accelerate the development of V2O5 cathode in rechargeable lithium ion batteries.