Sr surface segregation on La0.6Sr0.4Co0.2Fe0.8O3-δ porous solid oxide fuel cell cathodes

Hongqian Wang, Scott A Barnett

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Scopus citations

Abstract

La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) symmetric-electrode cells with Gd0.1Ce0.9O1.95 (GDC) electrolytes were aged in ambient air at temperatures ranging from 550 to 800°C for times up to 1400 h, without current/polarization. Electrochemical impedance spectroscopy measurements, taken periodically during the tests at a testing temperature of 700°C for cells aged ≥ 700°C, showed a continuous increase in polarization resistance. Focused ion beam-scanning electron microscopy (FIB-SEM) 3D tomography showed that the LSCF electrode did not coarsen measurably even at the highest ageing temperature, 800°C, ruling out LSCF microstructural changes as the mechanism behind the resistance increase. On the other hand, Sr surface segregation, determined by chemical etching with inductively coupled plasma-optical emission spectrometry (ICP-OES) detection, was found to increase with increasing ageing temperature > 650°C. The effect of Sr surface segregation on the oxygen surface exchange and diffusion processes is quantified by comparing the measured electrochemical and microstructural data.

Original languageEnglish (US)
Title of host publicationECS Transactions
PublisherElectrochemical Society Inc.
Pages905-913
Number of pages9
Volume78
Edition1
ISBN (Electronic)9781607685395
DOIs
StatePublished - May 30 2017
Event15th International Symposium on Solid Oxide Fuel Cells, SOFC 2017 - Hollywood, United States
Duration: Jul 23 2017Jul 28 2017

Other

Other15th International Symposium on Solid Oxide Fuel Cells, SOFC 2017
CountryUnited States
CityHollywood
Period7/23/177/28/17

ASJC Scopus subject areas

  • Engineering(all)

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