Characterization of amorphous Ta2O5 film as a novel anode material

Amorphous Ta2O5 film has been fabricated by reactive pulsed laser deposition and used for the first time as an anode material for the lithium ion rechargeable batteries. This thin film of anode material exhibits a reversible capacity of 400 mAh/g and a low initial irreversible capacity of; 100 mAh/g. Spectroelectrochemical measurements coupled with X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis, and electron diffraction have been employed to characterize the as-deposited tantalum oxide film electrode and its lithiated electrode. According to results of the XPS and measured high reversible capacity corresponding to more than 6 Li per Ta2O5, the reversible reaction of an amorphous tantalum oxide film with lithium different from the lithium ion insertion/extraction process for Li ion anodes is proposed. (C) 2003 The Electrochemical Society.