Raman spectroscopic investigations of Li-intercalated V₂O₅ xerogel

Xerogel films of vanadium oxide, obtained via spin-coating method, have been analyzed by a micro Raman probe. A comparison has been made among xerogel samples coated at an angular velocity of 1500 rpm (water molar concentration 1.8), the same compounds after vacuum dehydration (water molar concentration 0.5) and the dehydrated gels intercalated with different amounts of Li⁺ ion. Only minor spectral changes are observed in the xerogel films after the partial dehydration. On the contrary, significant spectral modifications occur after electrochemical intercalation of Li⁺ ion, even for relatively low concentration (0.15 molar fraction). In fact, the strongest Raman mode of the oxide, occurring at 170 cm^-1, disappears after intercalation, For increasing content of Li⁺ (up to 0.4 molar fraction) new Raman bands occur between 800 and 950 cm^-1.