Degradation of La0.6Sr0.4Fe0.8Co0.2O3-δ oxygen electrodes on Ce0.9Gd0.1O2-δ electrolytes during reversing current operation

Justin G. Railsback*, Hongqian Wang, Qinyuan Liu, Matthew Y. Lu, Scott A. Barnett

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

In order to assess the durability of La0.6Sr0.4Co0.2Fe0.8O3 oxygen electrodes in reversible solid oxide cells, current switched ~1000 h galvanostatic (0.7, 1.0, and 1.5 A/cm2) life tests were performed on symmetrical Ce0.9Gd0.1O2-electrolyte cells at 700°C. Cell operating voltage and resistance, the latter measured by impedance spectroscopy, were monitored throughout. Degradation was minimal for the 0.7 A/cm2 case. For the higher current densities, the cell voltage and resistance increased with time, although the cell appeared to stabilize after ~500 h in the 1.5 A/cm2 case. Post-test analyses showed no evidence of electrolyte cracking or delamination for any current. However, 3D imaging revealed measureable microstructural coarsening after 1.5 A/cm2 operation that was not present after 0.7 A/cm2 operation. Furthermore, the amount of Sr segregated onto LSCF surfaces was higher for the cells operated with current switching versus the as-prepared and zero-current cells. Analysis of the results suggest that much of the degradation was due to decreased oxygen surface exchange rate due to current-enhanced Sr segregation, with a smaller contribution due to microstructural coarsening. The possibility of extrapolating these accelerated tests to longer times is discussed.

Original languageEnglish (US)
Pages (from-to)F3083-F3090
JournalJournal of the Electrochemical Society
Volume164
Issue number10
DOIs
StatePublished - Jan 1 2017

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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