Electrochemical behavior and structural changes of V2O5 xerogel

Thin films of V2O5 xerogel were characterized by several in-situ techniques for different amount of intercalated Li+. Changes in the V2O5 mechanical properties were analyzed by electroacoustic impedance data, indicating that lithium intercalation does not produce an important change in the viscoelastic properties. So that, it is possible to use the electrochemical quartz crystal microbalance to measure mass change. Electrogravimetric results showed a significant participation of propylene carbonate molecules during charge/discharge cycles, associated with a significant expansion/contraction of the structure. The ultraviolet-visible spectrophotometry, chronoamperometry and electrochemical impedance spectroscopy data showed the influence of structural modifications on electronic and ionic properties during the intercalation process. The amorphization of the material in the discharged state produces a diminution in the charge carrier rate. Besides this, changes in the local symmetry of the vanadium ion by extended X-ray absorption fine structure experiments, were verified.