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Beyond the Structure–Property Relationship Paradigm: Influence of the Crystal Structure and Microstructure on the Li + Conductivity of La 2/3 Li x Ti 1− x Al x O 3 Oxides
Author(s) -
GarcíaMartín Susana,
MorataOrrantía Ainhoa,
AlarioFranco Miguel A.,
RodríguezCarvajal Juan,
Amador Ulises
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200700235
Subject(s) - microstructure , materials science , crystal structure , crystallography , neutron diffraction , octahedron , ionic conductivity , lithium (medication) , perovskite (structure) , conductivity , electrical resistivity and conductivity , ion , lanthanum , chemistry , inorganic chemistry , physics , medicine , organic chemistry , electrode , electrolyte , endocrinology , quantum mechanics
The crystal structures of several oxides of the La 2/3 Li x Ti 1− x Al x O 3 system have been studied by selected‐area electron diffraction, high‐resolution transmission electron microscopy, and powder neutron diffraction, and their lithium conductivity has been by complex impedance spectroscopy. The compounds have a perovskite‐related structure with a unit cell √2 a p ×2 a p ×√2 a p ( a p =perovskite lattice parameter) due to the tilting of the (Ti/Al)O 6 octahedra and the ordering of lanthanum and lithium ions and vacancies along the 2 a p axis. The Li + ions present a distorted square‐planar coordination and are located in interstitial positions of the structure, which could explain the very high ionic conductivity of this type of material. The lithium conductivity depends on the oxide composition and its crystal microstructure, which varies with the thermal treatment of the sample. The microstructure of these titanates is complex due to formation of domains of ordering and other defects such as strains and compositional fluctuations.