Electrochemical fabrication of anatase TiO2 nanostructure as an anode material for aqueous lithium-ion batteries

Nanostructured titanium oxide films are fabricated directly by an anodic electrodeposition strategy at an aqueous TiCl3 solution. Surface morphology shows that the deposited films are consisted of fine particles having 15–25 nm in diameter. Annealing temperature influences both the crystal structure and the electrochemical performance of the deposited titanium oxide. When the annealing temperature exceeds 300 °C, the poorly crystalline titanium oxide converts into anatase phase. Cyclic voltammograms (CVs) show that the anatase titanium oxide films exhibit reversible insertion/de-insertion of lithium ion in an aqueous LiOH electrolyte. The formation of lithiated titanium oxide is confirmed from an X-ray photoelectron spectroscopy. An optimal annealing temperature is found to be about 400 °C in terms of the CV peak current density. In addition, the diffusion coefficient of lithium ion in cathodic process (1.6 × 10−15 cm2 s−1) is higher than that of anodic process (9.4 × 10−16 cm2 s−1), probably due to the formation of higher O–Li bond strength during the lithium insertion.