Li + and Al 3+ site occupancies impact on ionic conductivity in Li (7−3x) Al x La 3 Zr 2 O 12 garnet - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Communication Dans Un Congrès Année : 2017

Li + and Al 3+ site occupancies impact on ionic conductivity in Li (7−3x) Al x La 3 Zr 2 O 12 garnet

Résumé

Cubic garnets Li(7−3x)AlxLa3Zr2O12 (LLAZO) exhibit high conductivity and are envisioned as electrolyte material for all-solid-state batteries. To better understand the role of Al 3+ , we investigated different Al-doped LLAZO prepared by conventional solid-state reaction. Cubic phase was formed at 900°C, confirmed by X-ray diffraction. Based on 6 Li, 7 Li and 27 Al MAS NMR spectroscopies, we identified for different Al doping levels the Li and Al site occupancies and investigated their mobility by 7Li static NMR with variable temperature. Ionic conductivity measurements on pellets were also performed using electrochemical impedance spectroscopy. Li and Al site occupancies were found dependent on Al doping levels and strongly impact ionic mobility. From our measurements, garnet with x=0.35 exhibits higher ionic conductivity than with x=0.24. Al ions were mainly found at octahedral sites (96h) for x=0.35 whereas they were mainly on tetrahedral sites (24d) for x=0.24. More vacancies were also found on tetrahedral sites for x=0.35, that could facilitate [octa-tetra-octa] diffusion pathway. The latter have been shown to be more favorable energetically, i.e more mobility. Some pellets were sintered using Spark Plasma Sintering (SPS) and further investigated. We found that SPS modifies the material as Li and Al site occupancies were different compared to non-sintered powders. Al occupancy on octahedral sites was increased for x=0.24 at levels comparable to non-sintered powders at x=0.35.

Domaines

Matériaux
Abstract EMRS_A. Castillo.pdf (226.89 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-01563394 , version 1 (17-07-2017)

Identifiants

  • HAL Id : hal-01563394 , version 1

Citer

Adriana Castillo, Thibault Charpentier, Saïd Yagoubi, Eddy Foy, Mélanie Moskura, et al.. Li + and Al 3+ site occupancies impact on ionic conductivity in Li (7−3x) Al x La 3 Zr 2 O 12 garnet. The 2017 E-MRS : European Materials Research Society, May 2017, Strasbourg, France. ⟨hal-01563394⟩
273 Consultations
30 Téléchargements

Partager

Gmail Facebook X LinkedIn More