• 한국수소및신에너지학회논문집
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• 제18권4호
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• pp.439-445
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• 2007

Proton exchange membrane Fuel Cells(PEMFCs) have been spotlighted because of their broad potential application for potable electrical devices, automobiles and residential usages. However, their utilization is limited to low temperature operation due to the electrolyte dehydration at high temperature. High temperature PEMFC operation offers high CO tolerance and easy water management. This review presents development of high temperature($120{\sim}200^{\circ}C$) PEMFC. Especially, PEMFC which is based on acid-doped PBI membrane is discussed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.92.2-92.2
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• 2011

고분자전해질 연료전지 (PEMFC)의 가격 결정 요인 중 막 전극 접합체 (MEA)가 차지하는 비중은 약 45%정도이며, 이것을 구성하는 주요 부품인 기체 확산층 (GDL)은 carbon paper나 carbon cloth 형태가 사용되고 있다. 그렇지만 GDL을 제조하는 공정은 매우 복잡하고, 그 가격이 너무 높은 단점이 있다. 본 연구에서는 카본블랙, 흑연 등의 탄소화합물과 polymer binder를 이용하여 단순화된 공정으로 GDL을 제조하였다. 또한, GDL의 물리적 특성이 전극 성능에 미치는 영향을 분석하기 위하여 표면 morphology, 접촉각 및 표면에너지, 전기전도도, 기체투과도, porosity, pore distrivution 등을 측정하였고, 각각의 GDL 표면에 동량의 Pt 촉매를 도포하여 MEA를 제작한 후 그 성능을 평가하였다.

• 전기화학회지
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• 제10권4호
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• pp.279-282
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• 2007

개질기에서 생산된 수소를 연료전지용 연료로 사용할 때에는 개질수소가 포함하고 있는 일산화탄소가 막-전극접합체의 촉매를 피독시켜서 연료전지 성능이 크게 감소된다. 본 논문에서는 개질수소에 포함된 일산화탄소가 스퍼터링 공정으로 제조된 박막층에 의하여 개선된 막-전극접합체의 성능에 어떠한 영향을 미치는지 연구하였다. 실험결과 Pt와 Ru박막은 MEA의 단위전지 성능을 개선하였으며, 금속박막은 막-전극접합체의 일산화탄소에 대한 내구성을 증가시켰다. 산화전극으로의 공기주입 운전기법은 막-전극접합체의 일산화탄소에 대한 내구성을 증가시켰다. 게다가 Pt, Ru그리고 PtRu박막은 공기주입 운전에 영향을 주는 것으로 확인되었다.

• 전기화학회지
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• 제9권3호
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• pp.118-123
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• 2006

반복적인 작동/멈춤에 의해 고분자전해질 연료전지의 성능 감소가 촉진되며, 이는 연료전지 자동차의 상용화를 위해 반드시 해결되야 한다. 고분자전해질 연료전지 스택의 운전을 정지했을 때 연료극 유로에는 수소가, 공기극 유로에는 공기가 남아 있어 연료전지가 열림회로 전위 상태에 한동안 유지되며 이로 인해 촉매의 소결이 촉진되고 과산화수소 라디칼이 형성되어 전해질를 분해시키는 것으로 보고되고 있다. 본 연구에서는 반복적인 작동/멈춤이 따라 고분자전해질 연료전지의 성능 감소와 막-전극 접합체의 특성에 미치는 영향을 조사하고, 운전 정지 시 잔존 수소를 제거함으로써 연료전지 스택의 내구성을 향상시키는 방법을 제안하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.180-184
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• 2005

An experimental study is performed to evaluate the performance and the efficiency by humidifying MEA and by making the double-tied catalyst layers in a fuel cell system which is taken into account the physical and thermal concept. An electrical output produced by PEFC(polymer Electrolyte Fuel Cell) is measured to assess the performance of the stack and the efficiency is also evaluated according to the different situation in which is placed with and without the humidification of MEA (Membrane Electrolyte Assembly). Subsequently, It is found that the measured values of stack voltage and current are influenced by the stack temperature, humidification, and the double-tied catalyst layers which gives more enhanced values to apply for electric units.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.8-18
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• 2012

This paper presents a three-dimensional, transient cold-start polymer electrolyte fuel cell (PEFC) model to numerically evaluate the effects of membrane electrode assembly (MEA) design and cell location in a PEFC stack on PEFC cold start behaviors. The cold-start simulations show that the end cell experiences significant heat loss to the sub-freezing ambient and thus finally cold-start failure due to considerable ice filling in the cathode catalyst layer. On the other hand, the middle cells in the stack successfully start from $-30^{\circ}C$ sub-freezing temperature due to rapid cell temperature rise owing to the efficient use of waste heat generated during the cold-start. In addition, the simulation results clearly indicate that the cathode catalyst layer (CL) composition and thickness have an substantial influence on PEFC cold-start behaviors while membrane thickness has limited effect mainly due to inefficient water absorption and transport capability at subzero temperatures.

• 한국수소및신에너지학회논문집
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• 제23권2호
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• pp.125-133
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• 2012

Nafion ionomer located in electrode helps to increase the platinum utilization and proton conductivity. To achieve higher performance in PEMFCs, it is important an optimum Nafion content in the electrode. As the platinum loading and fabricated method depend on the optimum Nafion content. In this study, we have examined the interrelationship between platinum loading and Nafion content fabricated by decal transfer method. For electrodes with 0.25 and 0.4 mg/$cm^2$ Pt loading, best performance was obtained at 25 wt.% Nafion ionomer loading. It is also found that MEA with 0.25 mg/$cm^2$ Pt, the optimum Nafion content appears differently at low and high current density.

• 전기화학회지
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• 제15권2호
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• pp.109-114
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• 2012

고분자전해질 연료전지 (PEMFC)의 공기극을 양극산화 알루미늄 (AAO) 템플레이트를 이용하여 제조하고 촉매층의 구조적 특성을 주사현미경 (SEM) 측정과 BET (Brunauer-Emmett-Teller) 분석을 통해 알아보았다. SEM 측정을 통해 일정한 크기와 모양의 Pt nanowire 가 규칙적으로 형성된 것을 확인할 수 있었다. BET 분석을 통해 AAO 템플레이트로 인하여 20-100 nm 크기의 기공 분포가 증가한 것을 확인하였다. 단위전지 성능평가와 임피던스 측정을 통하여 막-전극접합체 (MEA)의 전기화학적 특성을 분석하였다. 그 결과, AAO 템플레이트를 이용하여 제조한 MEA는 촉매층의 구조 개선으로 인하여 물질 전달 저항을 감소시킬 수 있었으며, 25%의 단위전지 성능이 향상되었다.

• 한국수소및신에너지학회논문집
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• 제19권1호
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• pp.18-25
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• 2008

The membrane electrode assembly(MEA) was prepared by a nonequilibrium impregnation- reduction (I-R) method. Nafion 117 and covalently cross-linked sulfonated polyetherether with tungsto- phosphoric acid (CL-SPEEK/TPA30) prepared by our laboratory, were chosen as polymer electrolyte membrane(PEM). $Pt(NH_3)_4Cl_2$, $RuCl_3$ and reducing agent $(NaBH_4)$ were used as electrocatalytic materials. Electrochemical activity surface area(ESA) and specific surface area(SSA) of Pt cathodic electrode with Nafion 117 were $22.48m^2/g$ and $23.50m^2/g$ respectively under the condition of 0.8 M $NaBH_4$. But Pt electrode prepared by CL-SPEEK/TPA30 membrane exhibited higher ESA $23.46m^2/g$ than that of Nafion 117. In case of Pt-Ru anodic electrode, the higher concentration of Ru was, the lower potential of oxygen reduction and region of hydrogen desorption was, and Pt-Ru electrode using 10 mM $RuCl_3$ showed best properties of SSA $34.09m^2/g$ with Nafion 117. In water electrolysis performance, the cell voltage of Pt/PEM/Pt-Ru MEA with Nafion 117 showed cell property of 1.75 V at $1A/cm^2$ and $80{\circ}C$. On the same condition, the cell voltage with CL-SPEEK/TPA30 was the best of 1.73 V at $1A/cm^2$.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.523-530
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• 2019

For the low-Pt electrodes for polymer electrolyte fuel cells (PEMFCs), the optimization of ionomer content for anode catalyst layers was carried out. A commercial catalyst of 20 wt.% Pt/C was used instead of 50 wt.% Pt/C which is commonly used for PEMFCs. The ionomer content varies from 0.6 to 1.2 based on ionomer to carbon ratio (I/C) and the catalyst layer is formed over the electrolyte by the ultrasonic spray process. Evaluation of the prepared MEA in the unit cell showed that the optimal ionomer content of the air electrode was 0.8 on the I/C basis, while the hydrogen electrode was optimal at the relatively high ionomer content of 1.0. In addition, a large difference in cell performance was observed when the ionomer content of the hydrogen electrode was changed. Increasing the ionomer content from 0.6 to 1.0 by I/C in a hydrogen electrode with 0.05 mg/㎠ platinum loading resulted in more than double cell performance improvements on a 0.6 V. Through the analysis of various electrochemical properties in the single cell, it was assumed that the change in ionomer content of the hydrogen electrode affects the water flow between the hydrogen and air electrodes bounded by the membrane in the cell, which affects the overall performance of the cell. A more specific study will be carried out to understand the water flow mechanism in the future, and this study will show that the optimization process of hydrogen electrode can also be a very important cell design variable for the low-Pt and high-performance MEA.