• 81.07.De;
  • 82.45.Vp;
  • 82.45.Yz


The present work investigates lithium insertion into highly ordered nanotubular layers of TiO2 and its electrochromic effects. The nanotubes were formed by anodization of titanium in 1 M (H3PO4) + 1 M (NaOH) + 0.5wt% HF electrolyte at 20 V. This leads to nanotubular layers with a thickness of 1 ± 0.1 µm, individual tube diameter of 100 ± 10 nm and a tube wall thickness of 10 ± 2 nm. The cathodic behavior of tubes in the “as formed” amorphous phase and annealed to anatase were studied in a solution of 1 M LiClO4 in acetonitrile. Cyclic voltammograms and potential step experiments combined with reflectance measurements show for anatase nanotubes a well defined uptake potential for Li+ and a very strong and reversible electrochromic effect, while on the other investigated TiO2 structures the effects were much less pronounced. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)