Three-dimensional porous Fe0.1V2O5.15 thin film as a cathode material for lithium ion batteries

Three-dimensional (3D) porous V2O5 and Fe0.1V2O5.15 thin films have been prepared by electrostatic spray deposition technique. X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy are employed to investigate the structures and valence states of the films. Galvanostatic cell cycling, cyclic voltammetry and impedance spectroscopy are used to characterize their electrochemical properties. The Fe0.1V2O5.15 thin film shows much better cycling performance than the non-doped V2O5 thin film. Fe3+ can act as a stabilizing agent in the layered V2O5 and increase the reversibility of the charge and discharge processes towards deeper depth of lithium insertion/extraction. The dissolution of the active material in the electrolyte can also be significantly suppressed in the Fe-doped sample. Nevertheless, the Fe-doping causes a slight decrease in lithium ion diffusion coefficient.

► The special 3D-porous structure is a main factor to achieve good rate capability in both V2O5 and Fe0.1V2O5.15 samples.
► Fe-doping improves the cycling stability (195 mAh g−1 after 48 cycles).
► Lithium ion diffusion coefficients are derived in V2O5 and Fe0.1V2O5.15 electrodes.