La0.8Sr0.2Cr1 - xRuxO3 - δ-Gd0.1Ce0.9O1.95 solid oxide fuel cell anodes: Ru precipitation and electrochemical performance

W. Kobsiriphat, B. D. Madsen, Y. Wang, Laurence Marks, Scott A Barnett*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Scopus citations

Abstract

Composites containing La0.8Sr0.2Cr1 - xRuxO3 - δ (LSCrRu) with x = 0-0.25 and Gd0.1Ce0.9O1.95 (GDC) were studied as anodes in solid oxide fuel cells (SOFCs) with La0.9Sr0.1Ga0.8Mg0.2O3 - δ (LSGM) electrolytes. Electrode polarization resistance RP decreased during initial SOFC operation before reaching a minimum. The decrease was more rapid, and the ultimate RP value reached was generally lower, with increasing temperature and Ru content x. RP was stable at longer times except for x = 0.25 where it increased slightly. SOFCs with x = 0.18 anodes at 800 °C yielded power densities as high as 0.53 W/cm2 with an RP value, including the (La,Sr)(Co,Fe)O3-GDC cathode, of < 0.15 Ω cm2. Transmission electron microscopy revealed Ru nano-particles on LSCrRu surfaces; their size increased and their density decreased with increasing temperature. Increasing the Ru content increased the density of Ru surface particles at a given time and temperature. Measured early-stage Ru surface coverage values were consistent with a model where Ru supply to the LSCrRu surface was limited by Ru bulk out-diffusion, but the coverage saturated at longer times. There was surprisingly little Ru particle coarsening over times up to 1000 h at 800 °C, with Ru particles sizes remaining < 10 nm. The cell RP values generally decreased with increasing Ru nano-particle surface area.

Original languageEnglish (US)
Pages (from-to)257-264
Number of pages8
JournalSolid State Ionics
Volume180
Issue number2-3
DOIs
StatePublished - Mar 9 2009

Keywords

  • Composite anode
  • LaSrCrRuO
  • Ru precipitation
  • Solid oxide fuel cell

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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