Role of chemical heterogeneities on oxygen reduction kinetics on the surface of thin film cathodes

Wonyoung Lee, Zhuhua Cai, Bilge Yildiz

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

7 Scopus citations

Abstract

We investigated the effects of annealing and A-site stoichiometry on the surface heterostructures at (La0.8Sr0.2) yMnO3 (LSM, y≤1) dense thin films. While annealing at the high temperature induces cation segregation on LSM, A-site deficiency is hypothesized to reduce the level of Sr enrichment on the surface upon annealing by providing more space in the bulk of LSM for this relatively large cation. Localized chemical analysis by nano-probe Auger electron spectroscopy revealed the strong enrichment of Sr and Zr in particles that form on the surface of LSM films upon annealing. By systematically varying y from 1.0 to 0.95, A-site deficiency in LSM films was shown to suppress the Sr segregation on the surface and to decrease the particle density of these secondary phases on the surface of the annealed LSM films, suggesting a higher chemical stability of LSM surface with A-site deficiency. Our results contribute to understanding the elastic energy contributions to cation segregation on the surface of perovskite cathodes, and to elucidating the role of surface chemical heterogeneities to the ORR kinetics.

Original languageEnglish
Title of host publicationIonic and Mixed Conducting Ceramics 8
PublisherElectrochemical Society Inc.
Pages405-412
Number of pages8
Edition1
ISBN (Electronic)9781607683162
ISBN (Print)9781566779531
DOIs
StatePublished - 2012
Externally publishedYes
EventIonic and Mixed Conducting Ceramics 8 - 221st ECS Meeting - Seattle, WA, United States
Duration: 6 May 201210 May 2012

Publication series

NameECS Transactions
Number1
Volume45
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

Conference

ConferenceIonic and Mixed Conducting Ceramics 8 - 221st ECS Meeting
Country/TerritoryUnited States
CitySeattle, WA
Period6/05/1210/05/12

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