Role of the doping level in localized proton motions in acceptor-doped barium zirconate proton conductors
Journal article, 2018

Acceptor-doped barium zirconates are currently receiving considerable interest because of their high proton conductivity at intermediate temperatures, making them applicable as electrolytes in various electrochemical devices, but the mechanism of proton conduction is unclear. Here, we investigate the role of the acceptor-dopant level in the localized proton motions, i.e. proton transfers between oxygens and O-H reorientations, in hydrated samples of the proton conducting, acceptor-doped, perovskites BaZr1-xInxO3-x/2 with x = 0.10 and 0.20, using quasielastic neutron scattering (QENS). Analysis of the QENS spectra reveals that several proton transfer and O-H reorientational motions contribute to the QENS signal, as a consequence of the locally disordered nature of the structure due to the In doping of these materials, and establishes a generic and complex picture of localized proton dynamics in acceptor-doped barium zirconate based proton conductors. A comparison of the QENS results with vibrational spectroscopy data of the same materials, as reported in the literature, suggests a predominance of O-H reorientational motions in the observed dynamics. The highest doping level corresponds to a more distorted structure and faster dynamics, which thus indicates that some degree of structural disorder is favourable for high local proton mobility.


Daria Noferini

Institut Laue-Langevin

Chalmers, Chemistry and Chemical Engineering

Michael Marek Koza

Institut Laue-Langevin

Habibur Seikh Mohammad Rahman

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Zach Evenson

Heinz Maier-Leibnitz Zentrum (MLZ)

Technical University of Munich

Gøran J. Nilsen

Institut Laue-Langevin

ISIS Neutron and Muon Source

Sten Eriksson

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Andrew Wildes

Institut Laue-Langevin

Maths Karlsson

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 20 20 13697-13704

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Swedish Research Council (VR) (621-2010-3519), 2011-01-01 -- 2016-12-31.

Swedish Research Council (VR) (621-2010-3519), 2011-01-01 -- 2016-12-31.

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Swedish Research Council (VR) (2011-4887), 2012-01-01 -- 2014-12-31.

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Physical Sciences

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9/6/2018 1