Preparation of binder-free thin film Li4Ti5O12 anode with an adjustable thickness through anodic TiO2 nanotubes

Binder-free thickness-controllable Li4Ti5O12 for application in lithium ion batteries was fabricated by the reaction of Li2CO3 and anodic nanotubular TiO2 at 800 degrees C. As the concentration of Li2CO3 increased, the thickness of Li4Ti5O12 film increased, leading to increase in discharge capacity. The Li4Ti5O12 film prepared at the optimized concentration of Li2CO3 of 3.8 x 10(-6) mol displayed the maximum capacity of 104 mu A h cm(-2) at the first cycle, which corresponds to 103 mA h g(-1). We found that excess Li2CO3 led to creation of LiTiO2 phases in the Li4Ti5O12 film, which reduced the discharge capacity. For comparison, a Li4Ti5O12 film was prepared by the reaction of Li2CO3 on a non-anodized Ti foil. In this case, discharge capacity was dramatically reduced due to the formation of Li2TiO3 phases in Li4Ti5O12, which was confirmed by TEM and XRD analysis. (C) 2013 Elsevier B. V. All rights reserved.