• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2003년도 연료전지심포지움 2003논문집
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• pp.169-171
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• 2003

Organic/inorganic hybrid membranes have been prepared and evaluated as polymer electrolytes in a polymer electrolyte membrane fuel cell (PEMFC). Previously, partially fluorinated poly (arylenether) was synthesized and the polymer was sulfonated by fuming sulfuric acid$(30\%\;SO_3)$. Modification of these polymers with coupling agent and inorganic materials was carried out to prepare membranes. Membranes cast from these materials were investigated in relation to the proton conductivity and weight loss at the room temperature. It was found that these membranes had a higher conductivity of $10^{-2}\;Scm^{-1}$ at the room temperature. But inorganic materials have leaked out from the hybrid membrane. If this problem is resolved, organic/inorganic hybrid membranes will become satisfactory Polymer electrolytes for the PEMFC.

• 한국수소및신에너지학회논문집
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• 제18권2호
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• pp.157-163
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• 2007

During PEMFC operation, low current and low humidity conditions accelerate the degradation of perfluorosulfonic acid membrane. But, there have been no studies that clearly explain why these conditions accelerate the membrane degradation. In this study, the hydrogen permeability through the membrane, I-V polarization of MEA, fluoride emission rate(FER) in effluent water were measured during cell operation under low current densities and low relative humidity(RH). The experimental results were evaluated with oxygen radical mechanism the most commonly known for membrane degradation. It seems that low RH of anode is a good condition for $H{\cdot}$ radical formation on the Pt catalyst and the low current condition accelerates the $H{\cdot}$ to form $HO_2{\cdot}$ radical attacking the polymer membrane.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2290-2295
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• 2018

An acceleration stress test (AST) was performed to evaluate the durability of a polymer membrane in a polymer electrolyte membrane fuel cell (PEMFC) for 500 hours. Previous studies have shown that hydrogen crossover measured by linear sweep voltammetry (LSV) increases when the polymer membrane deteriorates in the AST process. On the other hand, hydrogen crossover of the membrane often decreases in the early stages of the AST test. To investigate the cause of this phenomenon, we analyzed the MEA operated for 50 hours using the AST method (OCV, RH 30% and $90^{\circ}C$). Cyclic voltammetry and transmission electron showed that the electrochemical surface area (ECSA) decreased due to the growth of electrode catalyst particles and that the hydrogen crossover current density measured by LSV could be reduced. Fourier transform infrared spectroscopy and thermogravimetric/differential thermal analysis showed that -S-O-S- crosslinking occurred in the polymer after the 50 hour AST. Gas chromatography showed that the hydrogen permeability was decreased by -S-O-S- crosslinking. The reduction of the hydrogen crossover current density measured by LSV in the early stages of AST could be caused by both reduction of the electrochemical surface area of the electrode catalyst and -S-O-S- crosslinking.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.37-40
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• 2003

Mesoporous zeolite - heteropolyacid-polymer hybrid membrane was prepared by sol-gel processes to make a proton conducting membrane. The crystallinity of mesoporous zeolite in composite membrane was increased with contents of heteropolyacid. Proton conductivity obtained from impedance measurements increases with contents of heteropolyacid, about 10$^{-3}$ S/cm in ca. 1.5 Wt% heteropolyacid.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 추계 총회 및 학술발표회
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• pp.149-151
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• 2004

• 한국막학회:학술대회논문집
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• 한국막학회 2008년도 춘계 총회 및 학술발표회
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• pp.206-209
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• 2008

• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.111-116
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• 2018

The environmental impacts of a 1 kW polymer electrolyte membrane fuel cell (PEMFC) system are quantitatively assessed by performing a Life Cycle Assessment (LCA) study. A PEMFC system produces electricity and heat simultaneously, so an appropriate allocation of associated inputs and outputs is performed between the electricity and heat produced. The environmental impacts of the PEMFC system on the impact categories such as global warming (GW), abiotic depletion (AD), acidification (AC), and eutrophication (EU) are assessed from the life cycle impact assessment. The impact indicator results of the impact assessment on these impact categories are obtained as $3.70E-01kg\;CO_2\;eq./kWh$, 1.86E-03 kg Sb eq./kWh, $4.09E-04kg\;SO_2\;eq./kWh$, and $1.88E-05kg\;PO_4{^{3-}}/kWh$, respectively. For all impact categories studied the most influential stage is the operation stage, which accounts for 98.8%, 98.7%, 70.3%, and 62.3% of the total impact on GW, AD, AC, and EU, respectively. For the impact categories of AD, AC, and EU, most of the environmental impacts during the operation stage is attributed to the production of city gas. However, for the impact category of GW, $CO_2$ emission from the reforming process of city gas is the main reason for the largest contribution of the operation stage to the total impact results.

• 한국수소및신에너지학회논문집
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• 제32권4호
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• pp.245-255
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• 2021

Various studies about metallic bipolar plates have been conducted to improve fuel cell performance through flow field design optimization. These research works have been mainly focused on fuel cells for vehicle, but not fuel cells for building. In order to reduce the price and volume of fuel cell stacks for building, it is necessary to apply a metallic flow field, In this study, for a metallic flow field applied to a fuel cell for building, the effect of a change in the flow field shape on the performance of a polymer electrolyte membrane fuel cell was confirmed using a model and experiments with a down-sizing single cell. As a result, the flow field using a metal foam outperforms the channel type flow field because it has higher internal differential pressure and higher reactants velocity in gas diffusion layer, resulting in higher water removal and higher oxygen concentration in the catalyst layer than the channel type flow field. This study is expected to contribute to providing basic data for selecting the optimal flow field for the full stack of polymer electrolyte membrane fuel cells for buildings.

• 멤브레인
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• 제29권2호
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• pp.80-87
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• 2019

염료감응형 태양전지는 지속 가능한 에너지원으로서 많은 관심을 받고 있다. 염료감응형 태양전지의 효율과 장기 안정성은 전극 물질과 전해질에 의해 크게 영향을 받는데 본 총설에서는 전해질에 초점을 두어 서술하고자 한다. 고분자 전해질막은 염료감응형 태양전지에서 기존의 액체 전해질을 대체하기 위한 대안으로 제시되어 왔다. 기존의 액체 전해질은 높은 효율을 나타낼 수 있지만 장기적인 안정성 문제와 누액 문제로 인해 고분자 전해질막에 관한 관심은 지속적으로 증가하고 있으며 매년 이와 관련된 논문들이 활발히 보고되고 있다. 본 총설은 염료감응형 태양전지를 위한 고분자 전해질막의 개념과 개발에 대한 간단한 설명을 다루고 있으며 고분자 매트릭스의 개질, 유-무기 가소제 및 이온성 액체와 같은 첨가제의 도입에 따른 염료감응형 태양전지의 효율과 전기화학적 특성에 대해서도 최근의 연구들이 정리되어 있다.

• 공업화학
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• 제23권5호
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• pp.445-449
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• 2012

고분자 전해질막 연료전지의 대량 생산을 위하여 막-전극 접합체(MEA) 활성화 방법의 개발이 중요한 현안이다. 현재 개발된 MEA활성화 방법은 시간이 많이 소요됨으로 인해 수소의 사용량 또한 증가하여 연료전지의 상용화에 큰 걸림돌이 되고 있다. 통상적인 활성화 방법은 활성화 원리를 주로 전해질 수화 관점에서 이해하였다. 반면, 본 논문에서 제안된 순환전압전류(cyclic voltammetry, CV) 활성화 방법은 전해질 및 촉매적 관점에서 별도로 분리하여 이해하였다. 따라서 전해질 관점에서는 상대 습도 100%인 가습된 질소를 공급하여 전극 및 막의 전해질을 수화시키는 과정으로 구성되고, 촉매적 관점에서는 CV 사이클을 수행하여 백금 촉매에 흡착되어 있는 불필요한 오염물질, 또는 산화피막을 제거하는 과정으로 수행된다. CV 활성화법은 2.5 h 내에 활성화가 종료되어 활성화 시간을 크게 단축시킬 수 있을 뿐만 아니라, 수소 사용량도 기존 활성화 방법에 비하여 1/4 이하로 감소시킬 수 있어서 효과적인 연료전지 활성화 방법으로 제안하고자 한다.