Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Diagnosis of Performance Degradation of Direct Methanol Fuel Cell Stack after Long-Term Operation

장기운전에 의한 직접메탄올 연료전지 스택의 성능 열화 분석

  • Kim, Sang-Kyung (Fuel Cell Research Center, Korea Institute of Energy Research) ;
  • Hyun, Min-Soo (Advanced Technology R&D Center, LS Industrial Systems Co., Ltd.) ;
  • Lee, Byung-Rok (Fuel Cell Research Center, Korea Institute of Energy Research) ;
  • Jung, Doo-Hwan (Fuel Cell Research Center, Korea Institute of Energy Research) ;
  • Peck, Dong-Hyun (Fuel Cell Research Center, Korea Institute of Energy Research) ;
  • Lim, Seong-Yop (Fuel Cell Research Center, Korea Institute of Energy Research)
  • 김상경 (한국에너지기술연구원 연료전지연구단) ;
  • 현민수 ((주) LS산전 선행기술연구소) ;
  • 이병록 (한국에너지기술연구원 연료전지연구단) ;
  • 정두환 (한국에너지기술연구원 연료전지연구단) ;
  • 백동현 (한국에너지기술연구원 연료전지연구단) ;
  • 임성엽 (한국에너지기술연구원 연료전지연구단)
  • Published : 2011.12.01
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Abstract

5-cell DMFC stack was fabricated and operated with the load of 4 A for 4000 hrs. After 4000 hrs operation peak power density of the stack reduced by 27.3%. Two of the five cells did now show performance degradation, the performance of other two was reduced by 40% and the performance of the other decreased by 60%. The amount of performance degradation of each cell by long-term operation did not correlate with the position in the stack. Platinum particle size in the anode catalyst layer of the MEA with the strongest degradation increased and the increase was severer on the position of methanol inlet than on the position of methanol outlet. However, platinum particle size in the cathode catalyst layers did not changed for all the MEA'. Ruthenium crossover from the anode catalyst layer to the cathode catalyst layer through the membrane was observed after 4,000 hrs operation by SEM-EDX and it occurred for all MEA' regardless of the degree of performance degradation. Atomic ratio of ruthenium to platinum in the cathode catalyst layer was the highest in the MEA with the strongest performance degradation.

50 $cm^2$의 활성면적을 가진 셀을 이용하여 5-셀 DMFC 스택을 제작하고 4 A의 부하로 4,000 시간 운전한 후 성능감소 및 성능 감소 원인을 분석하였다. 4,000 시간 운전 후 10 A에서 스택의 전력 밀도가 28.7% 감소하였으며 다섯개의 셀 중 두 개는 거의 성능저하가 일어나지 않았고 두 개는 약 40%의 성능 저하, 한 개는 약 60%의 성능 저하를 보였으며 각 셀별 성능저하의 정도의 차이는 스택 내에서의 위치와 상관관계가 없었다. 스택 내의 다섯 셀 중 가장 성능감소가 심하였던 셀의 경우 연료극 촉매층의 Pt 입자 크기가 증가하였으며 연료가 들어가는 쪽의 Pt 입자의 크기 증가가 더 심하였다. 그러나 4,000 시간 장기운전 후 공기극 촉매층에서는 Pt 입자 크기의 변화는 거의 없었다. 스택 내의 모든 셀에서 4,000 시간 운전 후 연료극 촉매에서 공기극 촉매로의 루테늄의 크로스오버가 SEM-EDX로 관찰되었으며 특히 성능감소가 심하였던 셀의 경우 공기극 촉매층에서 Ru/Pt의 비율이 가장 컸다.

Keywords

References

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