title: Fast Li-Ion-Conducting Garnet-Related Li7-3xFexLa3Zr2O12with UncommonI4̅3dStructure.
abstract: Fast Li-ion-conducting Li oxide garnets receive a great deal of attention as they are suitable candidates for solid-state Li electrolytes. It was recently shown that Ga-stabilized Li7La3Zr2O12crystallizes in the acentric cubic space groupI4̅3d. This structure can be derived by a symmetry reduction of the garnet-typeIa3̅dstructure, which is the most commonly found space group of Li oxide garnets and garnets in general. In this study, single-crystal X-ray diffraction confirms the presence of space groupI4̅3dalso for Li7-3xFexLa3Zr2O12. The crystal structure was characterized by X-ray powder diffraction, single-crystal X-ray diffraction, neutron powder diffraction, and Mößbauer spectroscopy. The crystal-chemical behavior of Fe3+in Li7La3Zr2O12is very similar to that of Ga3+. The symmetry reduction seems to be initiated by the ordering of Fe3+onto the tetrahedral Li1 (12a) site of space groupI4̅3d. Electrochemical impedance spectroscopy measurements showed a Li-ion bulk conductivity of up to 1.38 × 10-3S cm-1at room temperature, which is among the highest values reported for this group of materials.
authors: Department of Chemistry and Physics of Materials, University of Salzburg , Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors: Reinhard
authors: R
authors: Wagner
authors: Department of Chemistry and Physics of Materials, University of Salzburg , Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors: Günther J
authors: GJ
authors: Redhammer
authors: Center for Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, United States.
authors: Daniel
authors: D
authors: Rettenwander
authors: Department of Chemistry and Physics of Materials, University of Salzburg , Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors: Gerold
authors: G
authors: Tippelt
authors: Institute of Chemical Technologies and Analytics, Vienna University of Technology , Getreidemarkt 9/164EC, 1060 Vienna, Austria.
authors: Andreas
authors: A
authors: Welzl
authors: Institute of Chemical Technologies and Analytics, Vienna University of Technology , Getreidemarkt 9/164EC, 1060 Vienna, Austria.
authors: Stefanie
authors: S
authors: Taibl
authors: Institute of Chemical Technologies and Analytics, Vienna University of Technology , Getreidemarkt 9/164EC, 1060 Vienna, Austria.
authors: Jürgen
authors: J
authors: Fleig
authors: Department of Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin , Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors: Alexandra
authors: A
authors: Franz
authors: Department of Chemistry and Physics of Materials, University of Salzburg , Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors: Werner
authors: W
authors: Lottermoser
authors: Department of Chemistry and Physics of Materials, University of Salzburg , Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors: Georg
authors: G
authors: Amthauer