STUDY OF THE LITHIUM INTERCALATION DEINTERCALATION PROCESSES INTO V2O5 BY LINEAR VOLTAMMETRY AT SLOW SWEEP RATES

Linear voltammetry at slow sweep rates allows us to obtain, via the corresponding -dx/dE vs. x curves, more information than the charge/discharge curves, on the V2O5 electrochemical behavior during the intercalation and the deintercalation of the first lithium. In fact, the two first electroreduction steps of this material have been subdivided into two and three processes, respectively. X-ray diffraction studies on electrogenerated LixV2O5 compounds have shown that each of these processes corresponds to a given modification of the c lattice parameter when the lithium content is modified. Reoxidation of LixV2O5 COMPounds has shown that some lithium is irreversibly intercalated in the V2O5 Structure even for small x values. The LiV2O5 species produced, when the lithium intercalation is greater than 0.7 lithium per V2O5, is difficult to reoxidize; this may be the origin of the loss of the reversibility that we have observed during cycling.