| 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 |
| 이승훈, 윤종설, 차영철, 이준, 황해진, 문지웅1 |
인하대학교 신소재공학부
1요업기술원 에너지응용소재팀 |
| 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 |
| Seung-Hun Lee, Song-Seol Yoon, Young-Chul Cha, Jun Lee, Hae-Jin Hwang, Ji-Woong Moon1 |
School of Materials Science and Engineering, Inha University
1Korea Institute of Ceramic Enginerring and Technology, Energy & Applied Materials Laboratory |
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| ABSTRACT |
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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. |
| Key words:
Solid oxide fuel cell, BSCF, LBCF, Cathode, Perovskite, Mixed ionic and electronic conductor |
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