Lithium Insertion into Mixed Phase Titania Nanotubes

Abstract

Titanium dioxide nanotubes were obtained by a simple alkaline hydrothermal route forming titanate nanotubes in a first step and subsequent ion exchange with hydrochloric acid. The obtained TiO2 nanotubes were structurally characterized by powder X-ray diffraction, Raman spectroscopy, transmission electron microscopy. Electrochemical analysis by cyclic voltammetry shows the presence oif anatase and TiO2-B phase in the tubes. From Randles-Ševcik plots a diffusion-controlled anodic reaction is found for the anatase phase, the TiO2-B phase, however, exhibits a pseudocapacitive behavior. A quite high amount of TiO2-B phase present in our TiO2 nanotubes is responsible for high charge and discharge capacities exceeding those found by other research groups for comparable nanotube systems. Furthermore, galvanostatic long-time cycling proves a high stability of the TiO2 nanotubes.