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Improving Hydride Conductivity in Layered Perovskites via Crystal Engineering

preprint
submitted on 28.07.2020 and posted on 29.07.2020 by Harry W. T. Morgan, Harry J. Stroud, Neil Allan
Hydride ion conduction in layered perovskites is of great interest for sustainable-energy applications. In this report we study Ba2ScHO3, a recently synthesized oxyhydride with an unusual anion ordering, using a multifaceted density functional theory approach involving both transition state calculations and molecular dynamics simulations. Beyond simply identifying the key ion migration pathways, we perform detailed analysis of transition states and identify key interactions which drive trends in ionic mobility. Our key findings are that ionic mobility is, remarkably, independent of hydride-oxide disorder, the dominant migration pathway changes under pressure, and a reduction in A-site cation size accelerates hydride diffusion. Local structural flexibility along migration pathways is understood in terms of dimensionality and ionic size, and we thus identify crystal engineering principles for rational design of ion conductors. On the basis of our new insights into these materials, we predict that Sr2ScHO3 will show improved conductivity over existing analogues.

Funding

EP/L015722/1

Tier 2 Hub in Materials and Molecular Modelling

Engineering and Physical Sciences Research Council

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History

Email Address of Submitting Author

harry.morgan@chem.ox.ac.uk

Institution

Department of Chemistry, University of Oxford

Country

UK

ORCID For Submitting Author

0000-0001-9647-8807

Declaration of Conflict of Interest

No conflict of interest

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