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Enhanced Proton Conductivity in Y-Doped BaZrO 3 via Strain Engineering

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Fluri Aline, Marcolongo Aris, Roddatis Vladimir, Wokaun Alexander, Pergolesi Daniele, Marzari Nicola, Lippert Thomas,
Project The search for low temperature super protonic conductivity
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Original article (peer-reviewed)

Journal Advanced Science
Volume (Issue) 4(12)
Page(s) 1700467 - 1700467
Title of proceedings Advanced Science
DOI 10.1002/advs.v4.12

Open Access

URL http://doi.org/10.1002/advs.v4.12
Type of Open Access Publisher (Gold Open Access)

Abstract

The effects of stress-induced lattice distortions (strain) on the conductivity of Y-doped BaZrO3, a high-temperature proton conductor with key technological applications for sustainable electrochemical energy conversion, are studied. Highly ordered epitaxial thin films are grown in different strain states while monitoring the stress generation and evolution in situ. Enhanced proton conductivity due to lower activation energies is discovered under controlled conditions of tensile strain. In particular, a twofold increased conductivity is measured at 200 °C along a 0.7% tensile strained lattice. This is at variance with conclusions coming from force-field simulations or the static calculations of diffusion barriers. Here, extensive first-principles molecular dynamic simulations of proton diffusivity in the proton-trapping regime are therefore performed and found to agree with the experiments. The simulations highlight that compressive strain confines protons in planes parallel to the substrate, while tensile strain boosts diffusivity in the perpendicular direction, with the net result that the overall conductivity is enhanced. It is indeed the presence of the dopant and the proton-trapping effect that makes tensile strain favorable for proton conduction.
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