Ionic conductivity enhancement in Ti-doped Sr11Mo4O23 defective double perovskites

Authors
Lopez, Carlos Alberto; Pedregosa, Jose Carmelo; Fernández Díaz, M. T.; Alonso, J. A.
Publication Year
2017
Language
English
Format
article
Status
Published version
Description
A substantially higher ionic motion can be achieved by partially replacing Mo(VI) by Ti(IV) cations in the novel Sr11Mo4−xTixO23−δ (with x = 0.0, 0.5 and 1.0) electrolyte oxides, successfully enhancing the oxygen vacancy level. These phases can be rewritten as Sr1.75□0.25(Sr)(Mo,Ti)O5.75−δ highlighting the relationship with conventional double perovskites. This original structure presents a broken corner sharing connectivity of the octahedral framework, hence leading to a complex and highly defective network. These materials have been prepared in polycrystalline form by thermal treatment up to 1300 °C. The structures were refined from X-ray and neutron powder diffraction data collected at room temperature and at 500 and 800 °C for x = 1. At high temperature this perovskite shows a phase transition to cubic symmetry and also evidences a reversible process of removal/uptake of O-atoms as observed in the undoped phase. AC-conductivity measurements from impedance spectroscopy confirm that Ti-doping increases the ionic mobility by 70%, attaining ionic conductivity values as high as 3.2 × 10−3 and 1.8 × 10−2 S cm−1 at 650 and 800 °C, respectively.
Fil: Lopez, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; Argentina
Fil: Pedregosa, Jose Carmelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; Argentina
Fil: Fernández Díaz, M. T.. Institut Laue Langevin; Francia
Fil: Alonso, J. A.. Instituto de Ciencia de Materiales de Madrid; España
Subject
Otras Ciencias Químicas
Ciencias Químicas
CIENCIAS NATURALES Y EXACTAS
Access level
Open access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/65090