• 제목/요약/키워드: Gas diffusion layer

검색결과 265건 처리시간 0.033초

전처리가 그래핀을 코팅한 고체고분자 연료전지 분리판의 전기화학적 특성에 미치는 영향 (Effect of Pretreatments on Graphene Coated Bipolar Plate of PEMFC on Electrochemical)

  • 차성윤;이재봉
    • Corrosion Science and Technology
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    • 제13권6호
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    • pp.224-232
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    • 2014
  • Effect of pretreatments on the graphene coated bipolar plate of proton exchange membrane fuel cell(PEMFC) was investigated in simulated environments for PEMFC by using electrochemical measurement techniques. Interfacial contact resistance(ICR) between the graphene coated bipolar plate and the gas diffusion layer(GDL) was measured. The value of ICR decreased with an increase in compaction stress($20N/cm^2{\sim}220N/cm^2$). ICR of graphene coated bipolar plate was higher than that of bare 316L stainless steel. However, Potentiodynamic measurement results showed that the corrosion resistance of graphene coated bipolar plate was higher than that of bare 316L stainless steel. $H_2SO_4$ acid pretreatment was the most effective among various pretreatments. The lowest ICR and the corrosion current density were obtained when using $H_2SO_4$ solution pretreatment.

고분자전해질 수전해용 MEA의 촉매침투도에 따른 성능변화 (Performance change according to the catalyst intrusion rate in the MEA for the PEM water electrolysis)

  • 김홍열
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 추계학술대회 논문집
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    • pp.254-256
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    • 2009
  • The performances of proton exchange membrane (PEM) water electrolysis depend on many factors such as materials, geometries, fabrication methods, operating conditions, and so forth. The fabrication method is concerned, membrane electrode assemblies (MEA) are a most important part to show different performances by different fabrication methods. The performance change of PEM water electrolysis was experimentally measured according to the fabrication differences of the anode electrodes. One point of view is the catalyst intrusion rate to the anode gas diffusion layer (GDL), and the other point of view is the catalyst loading distribution in depth of the anode GDL. Results show that the performances of MEA with deep intrusion of the catalysts are better in the range of low current densities but worse at higher current densities. The catalyst loading distribution does not affect significantly to the performance of PEM water electrolyser.

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X선 영상기법을 이용한 고분자 전해질형 연료전지의 수분분포 가시화 (Visualization of Water Distribution in a Polymer Electrolyte Fuel Cell Using an X-ray Imaging Technique)

  • 임남윤;박구곤;김창수;이상준
    • 한국가시화정보학회지
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    • 제5권2호
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    • pp.33-38
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    • 2007
  • Water management in polymer electrolyte fuel cell (PEFC) has been receiving large attention as an important issue in practical applications. Proper water management is vital to achieve high performance and durability of PEFC. In this study, an X-ray imaging technique was employed to visualize the water distribution in a PEFC quantitatively. X-ray images of the PEFC components with and without water were distinguished clearly. From the visualized X-ray images, we could evaluate the water distribution in the region between separator and gas diffusion layer (GDL) quantitatively. In addition, the contact angle of water in the micro-channels was also clearly visualized.

하이드라진으로 환원시킨 그래핀을 코팅한 오스테나이트와 마르텐사이트 스테인리스 강 고체고분자형 연료전지 금속 분리판의 전기화학적 특성 평가 (Evaluation of Electrochemical Characteristics on Graphene Coated Austenitic and Martensitic Stainless Steels for Metallic Bipolar Plates in PEMFC Fabricated with Hydrazine Reduction Methods)

  • 차성윤;이재봉
    • Corrosion Science and Technology
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    • 제15권2호
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    • pp.92-107
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    • 2016
  • Graphene was coated on austenitic and martensitic stainless steels to simulate the metallic bipolar plate of proton exchange membrane fuel cell (PEMFC). Graphene oxide (GO) was synthesized and was reduced to reduced graphene oxide (rGO) via a hydrazine process. rGO was confirmed by FE-SEM, Raman spectroscopy and XPS. Interfacial contact resistance (ICR) between the bipolar plate and the gas diffusion layer (GDL) was measured to confirm the electrical conductivity. Both ICR and corrosion current density decreased on graphene coated stainless steels. Corrosion resistance was also improved with immersion time in cathodic environments and satisfied the criteria of the Department of Energy (DOE), USA. The total concentrations of metal ions dissolved from graphene coated stainless steels were reduced. Furthermore hydrophobicity was improved by increasing the contact angle.

Study of Flooding Prevention on Cathode Gas Diffusion Layer for Dynamic Load Fuel Cell

  • Choi, Dong-Won;You, Jin-Kwang;Rokhman, Fatkhur;Bakhtiar, Agung;Choi, Kwang-Hwan
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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    • pp.270-273
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    • 2011
  • Water management is important in proton exchange membrane fuel cell because the water balance has a significant impact on the overall fuel cell system performance. In fuel cell vehicle, the vehicle's power demand is dynamic; therefore, the dynamic water management system is required. This present study proposes a method to control the humidity of the input air in cathode side of the fuel cell vehicle. The simulation using several driving cycles shows the proposed air humidification control obtains a relatively good result. The liquid saturation level is seen constant at the target level although still there are small deviations at driving cycles which having averagely high power demands.

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복합재료 연료전지 스택의 열응력 해석 (Thermal Stress Analysis of a Fuel Cell Stack using an Orthotropic Material Model)

  • 전지훈;황운봉;엄석기;김수환;임태원
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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    • pp.206-209
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    • 2004
  • Mechanical behavior of a fuel stack was studied using an orthotropic material model. The fuel stack is essentially composed of a bipolar plate (BP), a gasket, an end plate, a membrane electrolyte assembly (MEA), and a gas diffusion layer (GDL). Each component is fastened with a suitable pressure. It is important to maintain a suitable contact pressure distribution of BP, because it influences the power efficiency of the fuel cell stack. When it is exposed to high temperature, its behavior must be stable. Hence, we performed stress analysis at high temperature as well as at room temperature. At high temperature, the contact pressure distribution becomes poor. Many patents have shown that using an elastomer can overcome this phenomena. Its effect was also studied. By using an elastomer, we found a good contact pressure distribution at high temperature as well as at room temperature.

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고분자전해질 수전해용 MEA의 촉매침투도에 따른 성능변화 (Performance Change according to the Catalyst Intrusion Rate in the MEA for the PEM Water Electrolysis)

  • 김홍열;이지정;이재영;이홍기
    • 신재생에너지
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    • 제5권4호
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    • pp.75-78
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    • 2009
  • The performances of proton exchange membrane (PEM) water electrolysis depend on many factors such as materials, geometries, fabrication methods, operating conditions, and so forth. The fabrication method is concerned, membrane electrode assemblies (MEA) are a most important part to show different performances by different fabrication methods. The performance change of PEM water electrolysis was experimentally measured according to the fabrication differences of the anode electrodes. One point of view is the catalyst intrusion rate to the anode gas diffusion layer (GDL), and the other point of view is the catalyst loading distribution in depth of the anode GDL. Results show that the performances of MEA with deep intrusion of the catalysts are better in the range of low current densities but worse at higher current densities. The catalyst loading distribution does not affect significantly to the performance of PEM water electrolyser.

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다공성 스테인리스 강 지지체의 표면개질에 따른 팔라듐-은 합금 수소 분리막의 수소 투과 선택도의 변화 (Effect of Surface Modification of the Porous Stainless Steel Support on Hydrogen Perm-selectivity of the Pd-Ag Alloy Hydrogen Separation Membranes)

  • 김낙천;김세홍;이진범;김현희;양지혜;김동원
    • 한국표면공학회지
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    • 제49권3호
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    • pp.286-300
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    • 2016
  • Pd-Ag alloy membranes have attracted a great deal of attention for their use in hydrogen purification and separation due to their high theoretical permeability, infinite selectivity and chemical compatibility with hydro-carbon containing gas streams. For commercial application, Pd-based membranes for hydrogen purification and separation need not only a high perm-selectivity but also a stable long-term durability. However, it has been difficult to fabricate thin, dense Pd-Ag alloy membranes on a porous stainless steel metal support with surface pores free and a stable diffusion barrier for preventing metallic diffusion from the porous stainless steel support. In this study, thin Pd-Ag alloy membranes were prepared by advanced Pd/Ag/Pd/Ag/Pd multi-layer sputter deposition on the modified porous stainless steel support using rough polishing/$ZrO_2$ powder filling and micro-polishing surface treatment, and following Ag up-filling heat treatment. Because the modified Pd-Ag alloy membranes using rough polishing/$ZrO_2$ powder filling method demonstrate high hydrogen permeability as well as diffusion barrier efficiency, it leads to the performance improvement in hydrogen perm-selectivity. Our membranes, therefore, are expected to be applicable to industrial fields for hydrogen purification and separation owing to enhanced functionality, durability and metal support/Pd alloy film integration.

탄소나노튜브의 저온성장을 위한 합성가스의 최적화 연구 (Optimization of Growth Gases for the Low-temperature Synthesis of Carbon Nanotubes)

  • 김영래;전홍준;이한성;곽정춘;황호수;공병윤;이내성
    • 한국전기전자재료학회논문지
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    • 제22권4호
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    • pp.342-349
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    • 2009
  • This study investigated the growth characteristics of carbon nanotubes (CNTs) by changing a period of annealing time and a $C_{2}H_{2}/H_2$ flow ratio at temperature as low as $450^{\circ}C$ with inductively coupled plasma chemical vapor deposition. The 1-nm-thick Fe-Ni-Co alloy thin film served as a catalyst layer for the growth of CNTs, which was thermally evaporated on the 15-nm-thick Al underlayer deposited on the 50-nm-thick Ti diffusion barrier. The annealing at low temperature of $450^{\circ}C$ brought about almost no granulation of the catalyst layer, and the CNT growth was not affected by a period of annealing time. A study of changing the flow rate of $C_{2}H_{2}$ and $H_2$ showed that as the ratio of the $C_{2}H_{2}$ flow rate to the $H_2$ flow rate was lowered, the CNTs were grown to be longer With further decreasing the flow ratio, the length of CNTs reached the maximum and then became shorter. Under the optimized gas flow rates, we successfully synthesized CNTs with a uniform length over a 4-inch Si wafer at $450^{\circ}C$.

Controlled Growth of Large-area Mono-, Bi-, and Few-layer Graphene by Chemical Vapor Deposition on Copper Substrate

  • Kim, Yooseok;Lee, Su-il;Jung, Dae Sung;Cha, Myoung-Jun;Kim, Ji Sun;Park, Seung-Ho;Park, Chong-Yun
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.380.2-380.2
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    • 2014
  • Direct synthesis of graphene using a chemical vapor deposition (CVD) has been considered a facile way to produce large-area and uniform graphene film, which is an accessible method from an application standpoint. Hence, their fundamental understanding is highly required. Unfortunately, the CVD growth mechanism of graphene on Cu remains elusive and controversial. Here, we present the effect of graphene growth parameters on the number of graphene layers were systematically studied and growth mechanism on copper substrate was proposed. Parameters that could affect the thickness of graphene growth include the pressure in the system, gas flow rate, growth pressure, growth temperature, and cooling rate. We hypothesis that the partial pressure of both the carbon sources and hydrogen gas in the growth process, which is set by the total pressure and the mole fraction of the feedstock, could be the factor that controls the thickness of the graphene. The graphene on Cu was grown by the diffusion and precipitation mode not by the surface adsorption mode, because similar results were observed in graphene/Ni system. The carbon-diffused Cu layer was also observed after graphene growth under high CH4 pressure. Our findings may facilitate both the large-area synthesis of well-controlled graphene features and wide range of applications of graphene.

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