The interplay and impact of strain and defect association on the conductivity of rare-earth substituted ceria

George F. Harrington; Lixin Sun; Bilge Yildiz; Kazunari Sasaki; Nicola H. Perry; Harry L. Tuller

doi:10.1016/j.actamat.2018.12.058

The interplay and impact of strain and defect association on the conductivity of rare-earth substituted ceria

George F. Harrington, Lixin Sun, Bilge Yildiz, Kazunari Sasaki, Nicola H. Perry, Harry L. Tuller

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

35 Citations (SciVal)

Abstract

The effects of strain on the ionic conductivity of rare-earth substituted CeO ₂ have been extensively studied, but the results have been inconsistent and focused upon the ‘optimised’ conductors such as Gd or Sm substituted CeO ₂ where defect association is minimised. By thermally annealing epitaxial films deposited by pulsed laser deposition, we varied the strain systematically, whilst avoiding any influence from interfacial or grain boundary effects. The activation energy of the in-plane conductivity was found to increase with increasing compressive biaxial strain, which was quantitatively in excellent agreement with previous computational and experimental studies. These results provide a much needed quantitative consensus on the effects of lattice strain on ionic transport. Furthermore, we demonstrate that the change in the activation energy for Yb-substituted CeO ₂ is around three times that for Gd or La substitutions for the same applied strain, indicating the important role played by defect association. These results have significant implications for ionic transport at reduced or ambient temperatures, where changes in conductivity due to strain may be several orders of magnitude larger for ‘non-optimised’ conductors compared with ‘optimised’ conductors. We rationalise our results by considering the defect-defect interactions in these materials and through force-field calculations.

Original language	English
Pages (from-to)	447-458
Number of pages	12
Journal	Acta Materialia
Volume	166
DOIs	https://doi.org/10.1016/j.actamat.2018.12.058
Publication status	Published - 31 Mar 2019

Bibliographical note

Funding Information:
GFH thanks R. De Souza and J. Kilner for illuminating discussions, and J. Santiso for assistance with the XRD RSM analysis. GFH also gratefully acknowledges financial support from a Kakenhi Grant-in-Aid for Encouragement of Young Scientists (B) Award (No. JP16K18235 ). The authors 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). L. Sun, B. Yildiz and H. L. Tuller acknowledge support for their research from the Department of Energy, Basic Energy Sciences under award number DE-SC0002633 (Chemomechanics of Far-From-Equilibrium Interfaces).

Publisher Copyright:
© 2019 Acta Materialia Inc.

Funding

GFH thanks R. De Souza and J. Kilner for illuminating discussions, and J. Santiso for assistance with the XRD RSM analysis. GFH also gratefully acknowledges financial support from a Kakenhi Grant-in-Aid for Encouragement of Young Scientists (B) Award (No. JP16K18235 ). The authors 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). L. Sun, B. Yildiz and H. L. Tuller acknowledge support for their research from the Department of Energy, Basic Energy Sciences under award number DE-SC0002633 (Chemomechanics of Far-From-Equilibrium Interfaces).

Keywords

Ceria
Ionic diffusion
Lattice strain
Point defects
Thin films

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

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10.1016/j.actamat.2018.12.058

Cite this

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title = "The interplay and impact of strain and defect association on the conductivity of rare-earth substituted ceria",

abstract = " The effects of strain on the ionic conductivity of rare-earth substituted CeO 2 have been extensively studied, but the results have been inconsistent and focused upon the {\textquoteleft}optimised{\textquoteright} conductors such as Gd or Sm substituted CeO 2 where defect association is minimised. By thermally annealing epitaxial films deposited by pulsed laser deposition, we varied the strain systematically, whilst avoiding any influence from interfacial or grain boundary effects. The activation energy of the in-plane conductivity was found to increase with increasing compressive biaxial strain, which was quantitatively in excellent agreement with previous computational and experimental studies. These results provide a much needed quantitative consensus on the effects of lattice strain on ionic transport. Furthermore, we demonstrate that the change in the activation energy for Yb-substituted CeO 2 is around three times that for Gd or La substitutions for the same applied strain, indicating the important role played by defect association. These results have significant implications for ionic transport at reduced or ambient temperatures, where changes in conductivity due to strain may be several orders of magnitude larger for {\textquoteleft}non-optimised{\textquoteright} conductors compared with {\textquoteleft}optimised{\textquoteright} conductors. We rationalise our results by considering the defect-defect interactions in these materials and through force-field calculations.",

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author = "Harrington, {George F.} and Lixin Sun and Bilge Yildiz and Kazunari Sasaki and Perry, {Nicola H.} and Tuller, {Harry L.}",

note = "Funding Information: GFH thanks R. De Souza and J. Kilner for illuminating discussions, and J. Santiso for assistance with the XRD RSM analysis. GFH also gratefully acknowledges financial support from a Kakenhi Grant-in-Aid for Encouragement of Young Scientists (B) Award (No. JP16K18235 ). The authors 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). L. Sun, B. Yildiz and H. L. Tuller acknowledge support for their research from the Department of Energy, Basic Energy Sciences under award number DE-SC0002633 (Chemomechanics of Far-From-Equilibrium Interfaces). Publisher Copyright: {\textcopyright} 2019 Acta Materialia Inc.",

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AU - Harrington, George F.

AU - Sun, Lixin

AU - Yildiz, Bilge

AU - Sasaki, Kazunari

AU - Perry, Nicola H.

AU - Tuller, Harry L.

N1 - Funding Information: GFH thanks R. De Souza and J. Kilner for illuminating discussions, and J. Santiso for assistance with the XRD RSM analysis. GFH also gratefully acknowledges financial support from a Kakenhi Grant-in-Aid for Encouragement of Young Scientists (B) Award (No. JP16K18235 ). The authors 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). L. Sun, B. Yildiz and H. L. Tuller acknowledge support for their research from the Department of Energy, Basic Energy Sciences under award number DE-SC0002633 (Chemomechanics of Far-From-Equilibrium Interfaces). Publisher Copyright: © 2019 Acta Materialia Inc.

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N2 - The effects of strain on the ionic conductivity of rare-earth substituted CeO 2 have been extensively studied, but the results have been inconsistent and focused upon the ‘optimised’ conductors such as Gd or Sm substituted CeO 2 where defect association is minimised. By thermally annealing epitaxial films deposited by pulsed laser deposition, we varied the strain systematically, whilst avoiding any influence from interfacial or grain boundary effects. The activation energy of the in-plane conductivity was found to increase with increasing compressive biaxial strain, which was quantitatively in excellent agreement with previous computational and experimental studies. These results provide a much needed quantitative consensus on the effects of lattice strain on ionic transport. Furthermore, we demonstrate that the change in the activation energy for Yb-substituted CeO 2 is around three times that for Gd or La substitutions for the same applied strain, indicating the important role played by defect association. These results have significant implications for ionic transport at reduced or ambient temperatures, where changes in conductivity due to strain may be several orders of magnitude larger for ‘non-optimised’ conductors compared with ‘optimised’ conductors. We rationalise our results by considering the defect-defect interactions in these materials and through force-field calculations.

AB - The effects of strain on the ionic conductivity of rare-earth substituted CeO 2 have been extensively studied, but the results have been inconsistent and focused upon the ‘optimised’ conductors such as Gd or Sm substituted CeO 2 where defect association is minimised. By thermally annealing epitaxial films deposited by pulsed laser deposition, we varied the strain systematically, whilst avoiding any influence from interfacial or grain boundary effects. The activation energy of the in-plane conductivity was found to increase with increasing compressive biaxial strain, which was quantitatively in excellent agreement with previous computational and experimental studies. These results provide a much needed quantitative consensus on the effects of lattice strain on ionic transport. Furthermore, we demonstrate that the change in the activation energy for Yb-substituted CeO 2 is around three times that for Gd or La substitutions for the same applied strain, indicating the important role played by defect association. These results have significant implications for ionic transport at reduced or ambient temperatures, where changes in conductivity due to strain may be several orders of magnitude larger for ‘non-optimised’ conductors compared with ‘optimised’ conductors. We rationalise our results by considering the defect-defect interactions in these materials and through force-field calculations.

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KW - Ionic diffusion

KW - Lattice strain

KW - Point defects

KW - Thin films

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The interplay and impact of strain and defect association on the conductivity of rare-earth substituted ceria

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

Access to Document

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