Physico-chemical properties of V2O5 thin films obtained by Atomic Layer Deposition

Vanadium oxides films were deposited on titanium substrate by Atomic Layer Deposition (ALD). AFM results showed a good stability and homogeneity of the vanadium oxide film even under thermal stress. XRD measurements have shown that the as-deposited films were amorphous ; after annealing under air at 500°C, the films were crytallised V 2 O 5 . XRD analyses have also revealed a strong orientation along the c axis. Electronic conductivity measurements performed in the frequency range 40 Hz to 1.8 GHz have evidenced small-polaron hopping with characteristic time of about 3.2x10 -10 s (at room temperature). Cyclic galvanostatic experiments in the potential range 3.8 / 2.8 V vs Li/Li + show a good reversibility of the V 2 O 5 film towards the lithium insertion / deinsertion reaction and especially a good adherence leading to a specific capacity of 135 mAh/g during cycling. Raman experiments provide new local information on the lithiated phases electrochemically produced.