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Fabrication Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF)/Ce0.9Gd0.1O2−δ (GDC) and La0.6Ba0.4Co0.2Fe0.8O3−δ (LBCF)/Ce0.9Gd0.1O2−δ (GDC) Composite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

중저온 SOFC용 Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF)/Ce0.9Gd0.1O2−δ (GDC) 및 La0.6Ba0.4Co0.2Fe0.8O3−δ (LBCF)/Ce0.9Gd0.1O2−δ (GDC) 복합체 양극 제조

  • Lee, Seung-Hun (School of Materials Science and Engineering, Inha University) ;
  • Yoon, Song-Seol (School of Materials Science and Engineering, Inha University) ;
  • Cha, Young-Chul (School of Materials Science and Engineering, Inha University) ;
  • Lee, Jun (School of Materials Science and Engineering, Inha University) ;
  • Hwang, Hae-Jin (School of Materials Science and Engineering, Inha University) ;
  • Moon, Ji-Woong (Korea Institute of Ceramic Enginerring and Technology, Energy & Applied Materials Laboratory)
  • 이승훈 (인하대학교 신소재공학부) ;
  • 윤종설 (인하대학교 신소재공학부) ;
  • 차영철 (인하대학교 신소재공학부) ;
  • 이준 (인하대학교 신소재공학부) ;
  • 황해진 (인하대학교 신소재공학부) ;
  • 문지웅 (요업기술원 에너지응용소재팀)
  • Published : 2007.12.31

Abstract

The potential candidates for IT-SOFCs cathode materials, $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) and $La_{0.6}Ba_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LBCF) powders, were synthesized by a EDTA-citrate combined method from $Sr(NO_3)_2$, $Ba(NO_3)_2$, $La(NO_3)_3{\cdot}6H_2O$, $Co(NO_3)_2{\cdot}6H_2O$, $Fe(NO_3)_3{\cdot}9H_2O$, citric acid and $EDTA-NH_3$. The cathode performance of symmetrical electrochemical cells consisting of BSCF-GDC or LBCF-GDC composite electrodes and a GDC electrolyte was investigated using by AC impedance spectroscopy at the temperature range of 500 to $700^{\circ}C$. It was found that a single phase perovskite could be successfully synthesized when the precursor is heated at $850^{\circ}C$ for 2 h. Due to thermal expansion mismatch between BSCF and GDC, the composite cathodes with lower GDC content than 45 wt% were peeled off from the GDC electrolyte and their electrode polarization resistance was estimated to be high. The thermal expansion coefficient of BSCF-GDC composites was decreased with increasing the GDC content and the electrode peeling off did not occur in BSCF-45 and 55 wt% GDC composites. BSCF-45 wt% GDC composite electrode showed the lowest area specific resistances (ASR) of 0.15 and $0.04{\Omega}{\cdot}cm^2$ at 600 and $700^{\circ}C$, respectively. On the other hand, LBCF-GDC composite cathodes showed higher ASR than the BSCF-45 and 55 wt% GDC and their cathode performance were decreased with the GDC content.

Keywords

References

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