Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La0.6Sr0.4CoO3-δ epitaxial films

doi:10.1039/c8ta08355j

This content will become publicly available on November 16, 2019

Title: Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La _0.6Sr _0.4CoO _3-δ epitaxial films

Abstract

The bulk-to-surface Sr segregation can seriously compromise the stability of oxygen electrocatalysis in La _1-xSr _xCoO _3-δ and limit its practical applications such as in solid oxide fuel cells. We show via in situ ambient pressure X-ray photoelectron spectroscopy (APXPS) that the surface Sr-segregation is a kinetically fast process and the equilibrium surface Sr-concentration follows Arrhenius law from 250 to 520 °C at a fixed p _O₂ = 1 × 10 ^-3 atm. We also show that application of a nanoscaled, atomic layer deposition (ALD) derived ZrO ₂ overcoat can effectively suppress the Sr-segregation by reducing the surface concentration of oxygen vacancies. Electrochemical impedance spectroscopy (EIS) study further confirms that the ALD-ZrO ₂-coated LSCo epitaxial film exhibits a much lower and more stable polarization resistance than the uncoated one at 550 °C for >300 hours, suggesting that Sr-segregation is the source of the higher resistance.

Authors:

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Univ. of South Carolina, Columbia, SC (United States). Dept. of Mechanical Engineering
Univ. of South Carolina, Columbia, SC (United States). Dept. of Mechanical Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Sciences and Technology Division
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Sciences and Technology Division
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source

Publication Date:: 2018-11-16

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of South Carolina, Columbia, SC (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)

OSTI Identifier:: 1491297

Alternate Identifier(s):: OSTI ID: 1482846

Grant/Contract Number:: AC05-00OR22725; AC02-05CH11231; DMR-1464112

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Materials Chemistry. A

Additional Journal Information:: Journal Volume: 6; Journal Issue: 47; Journal ID: ISSN 2050-7488

Publisher:: Royal Society of Chemistry

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats


                    Wen, Yeting, Yang, Tianrang, Lee, Dongkyu, Lee, Ho Nyung, Crumlin, Ethan J., and Huang, Kevin. Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La0.6Sr0.4CoO3-δ epitaxial films.  United States: N. p., 2018. 
        Web.  doi:10.1039/c8ta08355j.

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                    Wen, Yeting, Yang, Tianrang, Lee, Dongkyu, Lee, Ho Nyung, Crumlin, Ethan J., & Huang, Kevin. Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La0.6Sr0.4CoO3-δ epitaxial films.  United States.  doi:10.1039/c8ta08355j.

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                    Wen, Yeting, Yang, Tianrang, Lee, Dongkyu, Lee, Ho Nyung, Crumlin, Ethan J., and Huang, Kevin. Fri .  
        "Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La0.6Sr0.4CoO3-δ epitaxial films".  United States.  doi:10.1039/c8ta08355j.

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@article{osti_1491297,

  title        = {Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La0.6Sr0.4CoO3-δ epitaxial films},

  author       = {Wen, Yeting and Yang, Tianrang and Lee, Dongkyu and Lee, Ho Nyung and Crumlin, Ethan J. and Huang, Kevin},

  abstractNote = {The bulk-to-surface Sr segregation can seriously compromise the stability of oxygen electrocatalysis in La1-xSrxCoO3-δ and limit its practical applications such as in solid oxide fuel cells. We show via in situ ambient pressure X-ray photoelectron spectroscopy (APXPS) that the surface Sr-segregation is a kinetically fast process and the equilibrium surface Sr-concentration follows Arrhenius law from 250 to 520 °C at a fixed pO2 = 1 × 10-3 atm. We also show that application of a nanoscaled, atomic layer deposition (ALD) derived ZrO2 overcoat can effectively suppress the Sr-segregation by reducing the surface concentration of oxygen vacancies. Electrochemical impedance spectroscopy (EIS) study further confirms that the ALD-ZrO2-coated LSCo epitaxial film exhibits a much lower and more stable polarization resistance than the uncoated one at 550 °C for >300 hours, suggesting that Sr-segregation is the source of the higher resistance.},

  doi          = {10.1039/c8ta08355j},

  journal      = {Journal of Materials Chemistry. A},

  number       = 47,

  volume       = 6,

  place        = {United States},

  year         = {2018},

  month        = {11}

}

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Works referenced in this record:

Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides
journal, September 1976

Shannon, R. D.
Acta Crystallographica Section A, Vol. 32, Issue 5, p. 751-767
DOI: 10.1107/S0567739476001551

Enhanced oxygen reduction activity on surface-decorated perovskite thin films for solid oxide fuel cells
journal, January 2011

Mutoro, Eva; Crumlin, Ethan J.; Biegalski, Michael D.
Energy & Environmental Science, Vol. 4, Issue 9, p. 3689-3696
DOI: 10.1039/c1ee01245b

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Similar Records

This content will become publicly available on November 16, 2019

Title: Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La 0.6Sr 0.4CoO 3-δ epitaxial films

Abstract

Citation Formats

Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides journal, September 1976

Enhanced oxygen reduction activity on surface-decorated perovskite thin films for solid oxide fuel cells journal, January 2011

Title: Temporal and thermal evolutions of surface Sr-segregation in pristine and atomic layer deposition modified La _0.6Sr _0.4CoO _3-δ epitaxial films

Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides
journal, September 1976

Enhanced oxygen reduction activity on surface-decorated perovskite thin films for solid oxide fuel cells
journal, January 2011