Effect of CeO2 interlayer on ZrO2 electrolyte/La(Sr)CoO3 cathode for low-temperature SOFCs

• Published in: Solid state ionics Vol. 170; no. 1-2; pp. 1 - 7
• Main Authors: SHIONO, M, KOBAYASHI, K, LANNGUYEN, T, HOSODA, K, KATO, T, OTA, K, DOKIYA, M
• Format: Journal Article
• Language: English
• Published: 14.05.2004
• ISSN: 0167-2738
• DOI: 10.1016/j.ssi.2004.02.018

Porous Ce0.9Gd0.1O2-delta (GDC) and dense Ce0.8Sm0.2O2-delta (SDC) protection interlayer were introduced between Scandia-stabilized zirconia (SSZ) electrolyte and La0.6Sr0.4CoO3-delta(LSC) cathode of low-temperature SOFCs which operate at 600-800 deg C. The reactivity of the interlayer and the area-specific resistance (ASR) were investigated. EPMA analysis clearly showed that the reaction between LSC cathode and SSZ electrolyte did not occur even though GDC interlayer (3-6 mum) was porous. Moreover, the reaction between GDC interlayer and SSZ electrolyte which were fired at 1320 deg C was not observed. The ASR of LSC/GDC/SSZ measured by an AC impedance method was reduced 40% or more at each temperature compared to LSC cathode on a GDC pellet and showed a low value in 600-800 deg C. Thin and relatively dense SDC interlayer ( < 1 mum) was fabricated between LSC cathode and SSZ electrolyte by using 2-ethylhexanoic acid salts of Sm and Ce, and also in the system using this SDC thin interlayer, low ASR equivalent to LSC/GDC/SSZ was shown, and it became clear that the interlayer in this experiment is very effective in the reduction of ASR.