Electrochemical and structural properties of V2O5 thin films prepared by DC sputtering

Vanadium pentoxide thin films have been prepared by reactive DC magnetron sputtering from a vanadium metal target without annealing posttreatment. XRD, Raman and electrochemical experiments on 800 nm thin films show a high crystallinity of the deposits. Chronopotentiometric measurements performed in the two voltage range 3.8-2.8 and 3.8-2.15 V have demonstrated the promoting effect of the h 0 0 preferred orientation of V2O5 films in terms of polarization, kinetics and rate capability. The same reproducible deposition method is successfully applied to get films thicker than 1 μm in order to optimize the specific capacity. Effective high specific capacities can be then obtained with films 2.4 μm thick tested at high constant current density (100 μA cm−2): a stable capacity of 75 μAh cm−2 is available over 100 cycles in the 3.8-2.8 V potential range and 130 μAh cm−2 are still recovered in the range 3.8-2.15 V. These results indicate a promising cycling behaviour can be expected with thick films exhibiting a preferred orientation corresponding to V2O5 planes perpendicular to the substrate.