Free-standing V2O5 electrode for flexible lithium ion batteries

Free-standing and flexible V2O5 films have been prepared by the filtration of ultra-long nanowires synthesized through the hydrothermal technique. In order to improve the conductivity of the films, multiwalled carbon nanotubes (MWCNTs) were added to the V2O5 nanowires to form an integrated web-like structure. The structure of the V2O5 nanowires was investigated with X-ray diffraction and transmission electron microscopy. The possible use of these films as a cathode for lithium ion batteries was also investigated. The free-standing and flexible film electrodes exhibited good rate capability and excellent cycling performance, with a capacity of 140 mAh/g, even after 50 cycles at 1.7 °C in a voltage range of 2.5–4.0 V. The superior reversible lithium storage capability can be attributed to the fully reversible phase transitions of α-V2O5 through to δ-LiV2O5, good lithium diffusion in V2O5, and increased electronic conductivity and electrolyte diffusion from the incorporated MWCNT web.