title: Influence of Li(+) and H(+) Distribution on the Crystal Structure of Li(7-x)H(x)La3Zr2O12 (0 ≤ x ≤ 5) Garnets.
abstract: With appropriate doping or processing, Li7La3Zr2O12 (LLZO) is an excellent candidate to be used in Li batteries either as a solid electrolyte or as a separator between the Li anode and a liquid electrolyte. For both uses, the reactivity with water either from the air or in aqueous media is a matter of interest. We address here the structural changes undergone by LLZO as a result of H(+)/Li(+) exchange and relate them with the amount of H content and atomic distribution. Neutron diffraction is performed to elucidate Li and H location. Two different cubic phases derive from LLZO through H(+)/Li(+) exchange: Deep hydration up to 150 °C yields a noncentrosymmetric I4̅3d phase in which octahedral Li ions are exchanged by H ions, tetrahedral Li ions split into two sites with very different occupancies, and H ions form O4H4 entities around the less occupied tetrahedral site. Annealing above 300 °C results in a centrosymmetric Ia3̅d phase with lower H content in which Li ions occupy the usual sites of the cubic garnets and H ions occupy a split pseudooctahedral site. The centrosymmetric or noncentrosymmetric character is determined by the temperature at which exchange is performed and the H content. Both factors are not independent: at low temperature, the high H content favors H ordering around the vacant tetrahedra, while low H content and higher mobility at 350 °C lead to a disordered configuration of Li and H ions. The deeply hydrated garnets are stable up to at least 300 °C and also upon aging at room temperature.
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , E- 50009 Zaragoza, Spain.
authors.forename: Alodia
authors.initials: A
authors.lastname: Orera
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , E- 50009 Zaragoza, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Larraz
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , E- 50009 Zaragoza, Spain.|Institut Laue-Langevin , 38042 Grenoble Cedex 9, France.
authors.forename: José Alberto
authors.initials: JA
authors.lastname: Rodríguez-Velamazán
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , E- 50009 Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Campo
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , E- 50009 Zaragoza, Spain.
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Sanjuán