The effect of titanium on the lithium intercalation capacity of V2O5 thin films

Abstract The effect of Ti incorporation on lithium intercalation capacity of V 2 O 5 thin films prepared by spin coating using metalorganic (MO) and inorganic sol-gel (SG) precursors on indium tin oxide coated glass substrates have been investigated. Earlier studies show that V 2 O 5 –TiO 2 oxide system has a higher cyclic stability than V 2 O 5 . However, there is controversy concerning the capacity of these mixed phases. We observe that upon incorporation of 5% Ti in MO films the lithium intercalation capacity decreases from 47 mC/cm 2 to 27 mC/cm 2 , while for the SG films, the capacity increases from 14 mC/cm 2 to 27 mC/cm 2 . We attribute this difference in the lithium intercalation capacity of the 5% Ti doped V 2 O 5 films prepared by MO and SG precursors to the variation in the nonstoichiometry and the particle size. We find that it is essential to have a critical V:O ratio to achieve high intercalation capacity. Any deviations from this critical V:O ratio leads to a decrease in capacity and films having similar nonstoichiometry have similar values of intercalation capacity and diffusion coefficient.