Strain-modified ionic conductivity in rare-earth substituted ceria: effects of migration direction, barriers, and defect-interactions

George F. Harrington, Sunho Kim, Kazunari Sasaki, Harry L. Tuller, Steffen Grieshammer

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4 Citations (SciVal)

Abstract

It is crucial to understand how ionic transport in functional oxides is affected by strain, which may unintentionally occur during the fabrication or operation of electrochemical devices or may be intentionally engineered for improved functional properties. In this work, the change in ionic conductivity of biaxially strained epitaxial films of rare-earth substituted ceria was measured. By thermally annealing strained epitaxial films, the strain state was varied, and the conductivity was extracted without contributions from grain boundaries. It is shown that transport in the out-of-plane direction, with respect to the strained axes, is more sensitive to the strain state than in the in-plane direction. In addition, the size of the rare-earth substitutionals significantly impacts the extent of the strain effect on the ionic conductivity. The conductivity was simulated by the kinetic Monte Carlo method based on energies from density functional theory to deconvolute the effects of strain on the migration barriers and defect interactions. It was revealed that both the barriers and interactions contribute to the strain-modified transport, however, it is important to take into account the long-range motion rather than individual barriers and interactions. These findings provide new generalized insights into how strain affects ionic transport in crystalline materials, which may lead to a more sophisticated approach to engineering functional oxides.

Original languageEnglish
Pages (from-to)8630-8643
Number of pages14
JournalJournal of Materials Chemistry A
Volume9
Issue number13
DOIs
Publication statusPublished - 9 Apr 2021

Bibliographical note

Funding Information:
S. G. gratefully acknowledges the computing time granted by the JARA Vergabegremium and provided on the JARA Partition part of the supercomputer CLAIX at RWTH Aachen University. G. F. H. gratefully acknowledges nancial support from a Kakenhi Grant-in-Aid for Encouragement of Young Scientists (B) Award (No. JP18K13992), and the Platform of Inter/ Transdisciplinary Energy Research Support Program (Q-pit) at Kyushu University. G. F. H., H. L. T., and K. S. are also grateful for support from the Progress 100 program of Kyushu University, and the International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), both supported by MEXT, Japan, and the Center of Innovation Science and Technology based Radical Innovation and Entrepreneurship Program (COI Program), by the Japan Science and Technology Agency (JST) (grant number: JPMJCE1318). H. L. T acknowledges support for his research from the Department of Energy, Basic Energy Sciences under award number DE-SC0002633 (Chemomechanics of Far-From-Equilibrium Interfaces).

Publisher Copyright:
© The Royal Society of Chemistry 2021.

ASJC Scopus subject areas

  • General Chemistry
  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

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