Publication:
Study of the La₁/₂+₁/₂ₓLi₁/₂-₁/₂ₓTi₁-ₓAlₓO₃ (0 ≤ x ≤ 1) solid solution. A new example of percolative system in fast ion conductors

Thumbnail Image
Identifiers
URI: https://hdl.handle.net/10016/31262
ISSN: 0925-8388
ISSN: 1873-4669 (online)
DOI: https://doi.org/10.1016/j.jallcom.2017.05.278
UXXI: AR/0000020247
Files
study_JAC_2017_ps.pdf (2.35 MB)
Publication date
2017-10-05
Defense date
Authors
Advisors
Tutors
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier B.V.
Impact
Google Scholar
Export
Research Projects
Organizational Units
Journal Issue
Abstract
The synthesis by solid state reaction of new fast ion conductors with perovskite structure was carried out. The crystal structure and electric properties of the La1/2+1/2xLi1/2-1/2xTi1-xAlxO3 (0 ≤ x ≤ 1) solid solution were investigated by powder X-ray diffraction and impedance spectroscopy. All compositions of the La1/2Li1/2TiO3-LaAlO3 system, exhibited a single cubic perovskite structure (ac approximate to 3.87-3.79 angstrom; SG Pm-3m). The progressive decrease in the unit cell parameters agrees with the lower ionic radii of Al3+ in relation to Ti4+, which are allocated in the same octahedra. An upward deviation from the lineal ideal solid solution behavior described by Vegard's law was observed and it was tentatively associated with a volume excess created by solid dilution of non-isovalent cations. Structural features were deduced from Rietveld analysis of XRD patterns. Ti(Al)O6 octahedra are regular and La/vacancies are randomly distributed in A-site of the perovskite. The conductivity decreased almost four orders of magnitude with the Li content. This important decrease on the conductivity was attributed to the charge carrier (Li+) decrease and the blockade of the perovskite conduction pathways by La ions, according to a three dimensional percolative process. In consequence we present here a new example of percolative system of ionic conductors and the results confirm the important role played by effective vacant A-sites, neff = [Li] + nA, on Li conductivity of this fast ion conductors family with perovskite structure.
Description
Keywords
X-Ray diffraction, Ionic conduction, Solid-state electrolyte, Li-batteries, Percolative phenomena
Bibliographic citation
Journal of alloys and compounds, 720, Oct. 2017, Pp. 460-465
Collections
DCIMIQ - CIMIQ - SPM - Artículos de Revistas
OpenAIRE: Open Access Infrastructure for Research in Europe