Published online by Cambridge University Press: 10 February 2011
We report on investigations of V2O5 thin film cathodes prepared by pulsed laser deposition and the phase transformations which occur during electrochemical cycling. Our experimental results on PLD-grown, textured V2O5 crystalline films concur with reports in the literature that there is a voltage threshold above which, cycling appears to be completely reversible and below which, cycling appears to be irreversible. Crystalline films discharged beyond the threshold to 2.0 V vs. Li exhibited an immediate and continuous fade in capacity as well as a ∼90% decrease in XRD peak intensity and a similar decrease in Raman signal intensity in as few as 10 cycles. We have made co-phase material by both electrochemically discharging virgin, crystalline V2O5 and by further discharging previously cycled films which showed irreversible structural changes.