Influence of current collecting and functional layer thickness on the performance stability of La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.8Sm0.2O1.9 composite cathode

S. A. Muhammed Ali, Mustafa Anwar, Lily Siong Mahmud, Noor Shieela Kalib, Andanastuti Muchtar, Mahendra Rao Somalu

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The effect of current collecting layer (CCL) and cathode functional layer (CFL) thicknesses on the catalytic activity of the La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -Ce 0.8 Sm 0.2 O 1.9 (LSCF-SDC) composite cathode was investigated by electrochemical impedance spectroscopy at 600 °C for 100 h. Results revealed that the charge transfer process associated with the incorporation of O 2− ions and the surface oxygen reduction reaction rate are dependent on CFL and CCL thicknesses, respectively. Area-specific resistance is dependent on CCL thickness in high-frequency arcs and on CFL thickness in low-frequency arcs. No significant change was observed in area-specific resistance value as the thickness of LSCF CCL decreased (25–5 μm) while the LSCF-SDC CFL thickness (5-25 μm) was gradually increased. However, the LSCF-SDC composite cathode (without CCL) showed poor catalytic activity toward the oxygen reduction reaction and had a high area-specific resistance value (3.31 Ω cm 2 ). When LSCF CCL (5 μm) was used, the area-specific resistance value decreased by 16 times relative to the ASR of a sample without CCL. The field emission scanning electron microscopy results indicated that these cathodes exhibited a clear change in microstructure on the surface of the LSCF CCL after 100 h of thermal treatment in oxygen. The particle agglomeration and Sr surface segregation affected the surface catalytic activity toward oxygen reduction reaction at the LSCF CCL. As a result, the ASR value increased gradually in 100 h thermal treatment. [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)1155-1164
Number of pages10
JournalJournal of Solid State Electrochemistry
Volume23
Issue number4
Early online date9 Feb 2019
DOIs
Publication statusPublished - Apr 2019

Keywords

  • Composite cathode
  • Current collector
  • Solid oxide fuel cell
  • Stability
  • Thickness

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Electrochemistry
  • Electrical and Electronic Engineering

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