Characteristics of amorphous WO3 thin films as anode materials for lithium-ion batteries

Amorphous WO3 thin films were fabricated on copper substrate by the magnetron sputtering technique. X-ray diffraction and X-ray diffraction pattern confirm the formation of phase is pure WO3. The as-prepared WO3 thin films as anode materials exhibit good electrochemical properties such as high reversible capacity, good cyclic stability and high rate capability in lithium-ion batteries. Specially, the WO3 electrode can exhibit high discharging capacity of about 142 μA h cm−2 (585 mA h g−1) even at the 100th electrochemical cycle at the current density of 24.3 μA h cm−2 (100 mA g−1). The redox couples, as shown in the CVs analysis, at around 1.02/2.14, 0.41/1.41 and 0.15/1.09 V in the 2nd and 3rd cycles are possibly attributed to the formation of the transition compound LixWO3 during lithium-ion inserting into and extracting from the WO3 thin film electrode. The good electrochemical properties of WO3 thin film make it become an excellent Li-ion storage material for rechargeable lithium batteries.