Next generation V2O5 cathode materials for Li rechargeable batteries

We report on investigations of vanadium oxide thin film cathodes prepared by three different synthesis techniques. 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 exhibited an immediate and continuous fade in capacity as well as a nearly 90% decrease in XRD peak intensity and a similar decrease in Raman signal intensity in as few as ten cycles. PLD-grown amorphous films show capacity loss of <2% over 200 cycles. Amorphous plasma-enhanced chemical vapor deposition (PECVD) films have capacities as :high as 1.5 Li/V with excellent stability over 3000 cycles. Solution-grown nanoparticles (<100 nm) of VO2 were spray-deposited and sintered at relatively low temperatures to produce nanoporous films. Cycling properties along with structural investigations by XRD and Raman scattering will be presented. (C) 1998 Published by Elsevier Science B.V. All rights reserved.