The electrochemical performance of smooth and highly ordered TiO2 nanotubes with an amorphous structure prepared by anodization was compared to crystalline anatase TiO2 nanotubes that were formed by post-treatment annealing. The amorphous TiO2 nanotube electrode shows enhanced electrochemical properties vs. the anatase electrode, which was evaluated in terms of discharge capacity, rate capability and cycling performance. The irreversible Li capacity observed in the amorphous TiO2 nanotube was primarily due to the formation of crystalline Li x TiO2, which is an inactive phase. The higher rate capability of the amorphous TiO2 nanotube electrode compared to the anatase electrode can be attributed to better reversibility and higher Li+ diffusivity.