Fabrication and characterization of silver-V2O5 composite thin films as lithium-ion insertion materials

Silver-vanadium pentoxide composite films have been fabricated by 355-nm pulsed laser reactive deposition on stainless steel substrates. XRD and SEM analyses showed that the composite films AgxV2O5 (x = 0.1-0.5) deposited at a substrate temperature of 300 degreesC in the presence of ambient 100 mTorr O-2 for 0.5 h were amorphous and became a polycrystalline structure after 2 h of deposition. The valence states of Ag and V for AgxV(2)O(5) composite film were examined by XPS measurement. The amorphous Ag-0.5 V2O5 composite film electrode exhibited a specific capacity as high as 396 mA(.)h/g in the range of 4.0-1.0 V at a 2 C rate and remained at a capacity of 260 mA(.)h/g at a high rate of 20 C with no obvious fading upon cycling more than 1000 cycles. In addition, the electronic conductivities of AgxV2O5 composite films were 2-3 orders of magnitude higher than that of pure V2O5 film. The dramatically improved rate and cycling performance might be related to the changes in microstructure of the AgxV2O5 composite films.