Structural and electrical properties of Li5TlO4
Abstract The structural and electrical properties of Li 5 TlO 5 were investigated. Li 5 TlO 4 was found to be sensitive to moisture or CO 2 in ambient environment. An electronically conducting brown to black thin layer, mainly composed of LiTlO 2 , was formed on the surface of Li 5 TlO 4 pellets during sintering and impedance measurement. The electronic conduction exceeded ionic conduction below 150°C. Above 150°C, ionic conduction became predominant with a maximum conductivity of 1×10 −3 (Ω-cm) −1 at 250°C for one of the samples. This value is high in comparison with the conductivity of other Li 5 M III O 4 isomorphs Above 400°C, a large increase in the conductivity, probably due to the presence of LiOH, was observed. Sample-to-sample differences in conductivity and variation during heating-cooling cycles were noted. These results are discussed in relation to the structural and thermal properties.