Open AccessEnhanced Proton Conductivity in Y‐Doped BaZrO 3 via Strain Engineering
Author(s) -
Fluri Aline,
Marcolongo Aris,
Roddatis Vladimir,
Wokaun Alexander,
Pergolesi Daniele,
Marzari Nicola,
Lippert Thomas
Publication year - 2017
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201700467
Subject(s) - materials science , conductivity , dopant , proton , doping , thermal diffusivity , ultimate tensile strength , proton transport , thermal conduction , trapping , condensed matter physics , chemical physics , composite material , chemistry , thermodynamics , optoelectronics , physics , quantum mechanics , ecology , biology
The effects of stress‐induced lattice distortions (strain) on the conductivity of Y‐doped BaZrO 3 , 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.