Structural and electrical properties of Li-doped TiO2 rutile ceramics

Li doped TiO2 rutile-type (TL) polycrystalline ceramics with Li concentration in the range 0≤x≤0.02 have been synthesized by a solid state reaction method. The structural properties were investigated using an x-ray diffraction (XRD) technique. The dc conductivity (σdc), obtained from impedance spectroscopy, has been investigated over the temperature range of 400–750 °C. The activation energy (Ea) of the samples was calculated from the absolute temperature dependence of the dc conductivity. The physical parameters, such as the lattice parameters, dc conductivity and activation energy, show changes in their behavior with increasing Li concentration. Such observed behaviors can be interpreted in terms of two different defect reaction mechanisms. For instance, for x≤0.01 the Li incorporates into interstitial sites, whereas for higher concentrations (0.01