• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.81.2-81.2
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• 2011

The gas diffusion layer (GDL) consists of two main parts, the GDL backing layer, called as a substrate and the micro porous layer (MPL) coated on the GDBL. In this process, carbon particles of MPL penetrates to the GDBL consequently forms MPL penetration part. In this study, the micro porous layer (MPL) penetration thickness is determined as a design parameter of the GDL which affect pore size distribution profile through the GDL inducing different mass transfer characteristics. The pore size distribution and water permeability characteristics of the GDL are investigated and the cell performance is evaluated under fully/low humidification conditions. Transient response and voltage instability are also studied. In addition, to determine the effects of MPL penetration on the degradation, the carbon corrosion stress test is conducted. The GDL that have deep MPL penetration thickness shows better performance in high current density region because of enhanced water management, however, loss of penetrated MPL parts is shown after aging and it induces worse water management characteristics.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.2
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• pp.65-73
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• 2012

The Gas Diffusion Layer (GDL) of fuel cell, are required to provide both delivery of reactant gases to the catalyst layer and removal of water in either vapor or liquid form in typical PEMFCs. In this study, the fabrication of GDL containing Micro Porous Layer (MPL) made of the slurry of PVDF mixed with carbon black is investigated in detail. Physical properties of GDL containing MPL, such as electrical resistance, gas permeability and microstructure were examined, and the performance of the cell using developed GDL with MPL was evaluated. The results show that MPL with PVDF binder demonstrated uniformly distributed microstructure without large cracks and pores, which resulted in better electrical conductivity. The fuel cell performance test demonstrates that the developed GDL with MPL has a great potential due to enhanced mass transport property due to its porous structure and small pore size.

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.32-39
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• 2024

The key components of a Phosphoric acid fuel cell (PAFC) are an electrode catalyst, an electrolyte matrix and a gas diffusion layer (GDL). In this study, we introduced a microporous layer on the GDL of PAFC to enhance liquid electrolyte management and overall electrochemical performance of PAFC. MPL is primarily used in polymer electrolyte membrane fuel cells to serve as an intermediate buffer layer, effectively managing water within the electrode and reducing contact resistance. In this study, electrodes were fabricated using GDLs with and without MPL to examine the influence of MPL on the performance of PAFC. Internal resistance and polarization curves of the unit cell were measured and compared to each other to assess the impact of MPL on PAFC electrode performance. As the results, the application of MPL improved power density from 170.2 to 192.1 mW/cm². MPL effectively managed electrolyte and water within the matrix and electrode, enhancing stability. Furthermore, the application of MPL reduced internal resistance in the electrode, resulting in sustained and stable performance even during long-term operation.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.270-278
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• 2007

PEMFC electrodes with various gas diffusion layers (GDL) were characterized to find out the effect of GDL on fuel cell performance. The physical properties of GDL such as electric conductivity, porosity, air permeability, water flux, PTFE content, etc had close relationship each other and affected on the variation of the cell performance. It was observed that the micro-porous layer (MPL) on carbon paper or cloth changed the physical properties of GDL and changed the cell performance. The variation of cell performance as a function of the physical properties of GDL showed different behaviors according to the amount of current density.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.4
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• pp.320-325
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• 2013

TUnitized reversible fuel cells (URFC) combine the functionality of a fuel cell and electrolyzer in one unitized device. For a URFC with proton exchange membrane, a titanium (Ti)-felt is applied to the gas diffusion layer (GDL) substrate at the oxygen electrode, and additionally titanium (Ti)-powders and TiN-powders are loaded in the GDL substrate as a micro porous layer (MPL). Double porous layer with TiN MPL was not acceptable for the URFC because both of fuel cell performance and electrolysis performance are degraded. The double porous layer with Ti-powder loading in the Ti-felt substrate influence rearly for the electrolysis performance. In contrast, the change of pore-size distribution brings a significant improvement of fuel cell performance under fully humidification conditions. This fact indicates that the hydrophobic meso-pores in the GDL play an important role for mass transport.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.3
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• pp.216-222
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• 2013

Durability characteristics of Gas Diffusion Layer(GDL) is one of the important issues for accomplishing commercialization of Proton Exchange Membrane Fuel Cell(PEMFC). It is strongly related to the performances of PEMFC because one of the main functions of GDL is to work as a path of fuel, air and water. When the GDL does not work on their proposed functions due to the degradation of durability, mass transfer in PEMFC is disturbed and it might cause the flooding phenomenon. Thus, investigating the durability of GDL is important and understanding the GDL degradation process is needed. In this study, electrochemical degradation with carbon corrosion is introduced. The carbon corrosion experiment is carried out with GDLs which have different MPL penetration thicknesses. After the experiment, the amount of degradation of GDL is measured with various properties of GDL such as weight, thickness and performance of the PEMFC. The degraded GDL shows loss of their properties.

• Applied Microscopy
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• v.47 no.3
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• pp.101-104
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• 2017

In this investigation, synchrotron X-ray imaging was used to investigate the water distribution inside newly developed gas diffusion media in polymer electrolyte membrane fuel cells. In-situ radiography was used to reveal the relationship between the structure of the microporous layer (MPL) and the water flow in a newly developed MPL equipped with randomly arranged holes. A strong influence of these holes on the overall water transport was found. This contribution provides a brief overview to some of our recent activities on this research field.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.38-46
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• 2022

Two different gas diffusion layers having noticeable differences in micro-porous layer's (MPL's) crack were studied as a substrate for the gas diffusion electrode (GDE) with different binder/carbon (B/C) ratios in high-temperature polymer electrolyte fuel cell (Ht-PEMFC). As a result, the performance defined as the voltage at 0.2 A/cm² and maximum power density from the single cells using GDEs from H23 C2 and SGL38 BC with different B/C ratios were compared. GDEs from H23 C2 showed a proportional increase of the voltage with the binder content on the other hand GDEs from SGL38 BC displayed a proportional decline of the voltage to the binder content. It was revealed that MPL crack influences the structure of catalyst layer in GDEs as well as affects the RC_athode which is in close connection with the Ht-PEMFC performance.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.71.1-71.1
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• 2010

고분자 전해질 연료전지(PEMFC) 내의 기체확산층(GDL)은 셀 내의 물 관리에 중요한 역할을 수행한다. 일반적으로 다공성 기제(GDBL) 위에 미세기공층(MPL)을 코팅한 2층 구조의 기체확산층이 사용되는데, 이 미세기공층은 카본파우더와 테프론의 혼합물로 이루어져 있으며 촉매층에서 발생한 물을 셀 밖으로 빠르게 배출하는 역할을 수행한다. 본 연구에서는 다양한 기공분포를 갖는 미세기공층을 제조하여 고분자 전해질 연료전지 성능에 미치는 영향을 분석하였다. 미세기공층 슬러리내에 암모늄염 계열의 기공형성제를 혼합하여 다공성 기제 위에 코팅한 후 다양한 온도조건에서 건조함에 따라 기공분포가 다른 미세기공층을 제조하였다. 이렇게 제조된 미세기공층의 물성은 수은기공도계, FE-SEM, 자체적으로 제조한 기체투과도 측정 장치를 사용하여 측정하였으며, 단위 전지 성능 측정은 두 개의 가습조건(RH100%, RH50%)에서 실시하였다. 기공분포 측정결과 건조온도가 높은 미세기공층은 건조온도가 낮은 미세기공층에 비해 직경이 1,000 - 20,000 nm 인 대공극(macropore)의 수가 많지만, 직경이 100 nm 이하의 미세공 (micropore)의 수가 적은 것을 확인하였다. 전지성능 측정 결과 고가습 조건 (RH100%)에서는 미세공 (micropore)이 발달한 미세기공층을 포함한 기체확산층을 사용한 경우 가장 우수한 성능을 보여고, 저가습 조건 (RH50%)에서는 대공극 (macropore)이 발달한 미세기공층을 포함한 기체확산층을 사용한 경우 가장 우수한 성능을 나타내었다. 이는 물배출에 유리한 미세공 (micropore)의 성질과 원료 기체의 이동에 유리한 대공극(macropore)의 성질에 의한 것으로 판단된다. 따라서 셀 운전 가습조건에 따라 최적화된 기공구조를 갖는 미세기공층을 사용함으로써 셀 운전 성능을 향상 시킬 수 있을 것으로 예상된다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.9
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• pp.683-694
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• 2008

The performance and durability of Polymer Electrolyte Fuel Cells (PEFCs) are strongly influenced by the uniformity of current density, temperature, species distributions inside a cell In order to obtain uniform distributions in them, the optimal design of flowfield must be a key factor. In this paper, the numerical study of land/channel flowfield optimizations is performed, using a multi-dimensional, multi-phase, non-isothermal PEFC model. Numerical simulations reveal more uniform current density and HFR(High Frequency Resistance) distributions and thus better PEFC performance with narrower land/channel width where the less severe oxygen depletion effect near the land region and more uniform contact resistance variation along the in-plane direction are achieved. The present study elucidates detailed effects of land/channel width and assist in identifying optimal flow-field design strategies for the operation of PEFCs.