Formation of Li2O in a chemically Li-intercalated V2O5 xerogel

We studied the electronic structure of a chemically Li-intercalated V2O5 xe rogel. The technique used in the study was V 2p and O 1s X-ray absorption s pectroscopy (XAS). The V ions in the as-prepared V2O5 xerogel are mostly in a pentavalent V5(+) state. The spectra show that the V ions are partially reduced to V4(+) and V3(+) states upon Li intercalation. The results also s how that low Li intercalation (x<l) affects mostly O 2p-V 3d mixed states, whereas for higher Li intercalation (x > 1), this mechanism saturates and l eads to Li,O formation. (C) 2001 Elsevier Science B.V. All rights reserved.