Structural analysis of lithium lanthanum titanate with perovskite structure

Abstract

Abstract Neutron and high‐energy X‐ray diffraction analysis of polycrystalline La 4/3‐x Li 3x Ti 2 O 6 have been performed to clarify the extent of disorder of the distribution of La and Li ions and to understand the relation of these distributions to ionic conduction. The distributions of the La and Li ions in a 10 × 10 × 20 cubic box (i.e., 10 × 10 × 10 unit cell) super‐structure, in which Ti and O atoms are fixed onto their regular sites, were obtained by the reverse Monte Carlo (RMC) structural modelling of both diffraction data sets. When the occupancy of La ions in the planes perpendicular to the c‐axis is analysed, one can find a La‐rich and La‐poor layers alternating, which is consistent with the results of earlier Rietveld analysis (Stramare et al., Chem. Mater. 15 , 3974 (2003) [1]). Of particular interest, the Li ions are found mainly on the interstitial sites between the O‐3 triangle plane of the TiO 6 octahedron and a La ion, which is different from the earlier work (Yashima et al., J. Am. Chem. Soc. 127 , 3491 (2005) [2]). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)