• Title/Summary/Keyword: Polymer electrolyte membrane

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PROPERTY CHANGES OF POLYMER ELECTROLYTE MEMBRANES WITH FREEZE/THAW CYCLES (동결/해동 조건에서 고분자막의 특성 변화 연구)

  • Park Gu-Gon;Lim Nam-Yun;Sohn Young-Jun;Park Jin-Soo;Lee Won-Yong;Kim Sae-Hoon;Lim Tae-Won;Kim Chang-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • pp.281-283
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    • 2005
  • Water management in polymer electrolyte membrane fuel cells(PEMFCs) is one of the most challenging issues. Freeze start-up in the automotive applications is also important research topic in the PEMFC field. Transportation of proton and separation of reactant gases are main roles of polymer electrolyte membranes. It has been known that water in the membrane conducts as a vehicle for the proton transportation. At sub-zero temperature, the frozen water blocks the access of reactant gases to the active sites of electrode as well as occurs the physical destruction of fuel cell structures. In this study, property changes of electrolyte membranes in the freeze conditions $(at\;-25^{\circ}C)$ were investigated. For the various amount of water contained membranes, the property changes, especially for the proton conductivity, were observed after several times of freeze/thaw$(-25\~80^{\circ}C)$ cycle.

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Understanding of Polymer Electrolyte Membrane for a Unitized Regenerative Fuel Cell (URFC) (일체형 재생 연료전지(URFC)용 고분자 전해질 막의 이해)

  • Jung, Ho-Young
    • Applied Chemistry for Engineering
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    • v.22 no.2
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    • pp.125-132
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    • 2011
  • A unitized regenerative fuel cell (URFC) as a next-generation fuel cell technology was considered in the study. URFC is a mandatory technology for the completion of the hybrid system with the fuel cell and the renewable energy sources, and it can be expected as a new technology for the realization of hydrogen economy society in the $21^{st}$ century. Specifically, the recent research data and results concerning the polymer electrolyte membrane for the URFC technology were summarized in the study. The prime requirements of polymer electrolyte membrane for the URFC applications are high proton conductivity, dimensional stability, mechanical strength, and interfacial stability with the electrode binder. Based on the performance of the polymer electrolyte membrane, the URFC technology combining the systems for the production, storage, utilization of hydrogen can be a new research area in the development of an advanced technology concerning with renewable energy such as fuel cell, solar cell, and wind power.

Organic / inorganic composite membrane for Polymer Electrolyte Membrane Fuel Cell (고분자전해질 연료전지용 유기/무기 복합 전해질)

  • Choi Seong Ho;Hong Hyeon Sil;Lee Heung Chan;Kim Yu Mi;Kim Geon
    • 한국전기화학회:학술대회논문집
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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.

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Ionic Cluster Mimic Membranes Using Ionized Cyclodextrin

  • Won Jong-Ok;Yoo Ji-Young;Kang Moon-Sung;Kang Yong-Soo
    • Macromolecular Research
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    • v.14 no.4
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    • pp.449-455
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    • 2006
  • Ionic cluster mimic, polymer electrolyte membranes were prepared using polymer composites of crosslinked poly(vinyl alcohol) (PVA) with sulfated-${\beta}$-cyclodextrins (${\beta}-CDSO_3H$) or phosphated-${\beta}$-cyclodextrins (${\beta}-CDPO(OH)_2$). When Nafion, developed for a fuel cell using low temperature, polymer electrolyte membranes, is used in a direct methanol fuel cell, it has a methanol crossover problem. The ionic inverted micellar structure formed by micro-segregation in Nafion, known as ionic cluster, is distorted in methanol aqueous solution, resulting in the significant transport of methanol through the membrane. While the ionic structure formed by the ionic sites in either ${\beta}-CDSO_3H$ or ${\beta}-CDPO(OH)_2$ in this composite membrane is maintained in methanol solution, it is expected to reduce methanol transport. Proton conductivity was found to increase in PVA membranes upon addition of ionized cyclodextrins. Methanol permeability through the PVA composite membrane containing cyclodextrins was lower than that of Nafion. It is thus concluded that the structure and fixation of ionic clusters are significant barriers to methanol crossover in direct methanol fuel cells.

Effect of Brij98 on Durability of Silver Polymer Electrolyte Membranes for Facilitated Olefin Transport (올레핀 촉진수송용 고분자 전해질막의 내구성에 대한 Brij98의 효과)

  • Kang, Yong-Soo;Kim, Jong-Hak;Park, Bye-Hun;Won, Jong-Ok
    • Membrane Journal
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    • v.16 no.4
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    • pp.294-302
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    • 2006
  • Silver polymer electrolytes are very promising membrane materials for the separation of olefin/paraffn mixtures. Olefin molecules are known to be transported through reversible complex formation with silver ions entrapped iii polymer matrix. However, they have poor long-term stability, which is very important fur the industrial application; the selectivity through the membrane decreases gradually with time mostly due to the reduction of silver ions ($Ag^+$) into silver nanoparticles ($Ag^0$). In this study, the stability of silver polymer electrolyte was investigated for poly(vinyl pyrrolidone) (PVP) and $AgBF_4$ system containing a surfactant, i.e. $C_{18}H_{35}(OCH_2CH_2)_{20}OH$ (Brij98) as a stabilizer. The reduction behavior of silver ions to silver nanoparticles in PVP was also investigated by atomic force microscopy (AFM) and UV-visible spectroscopy. It was found that the growth of silver nanoparticles was slower and selectivity of polymer electrolyte for propylene in propylene/propane was maintained longer time when Brij98 was added as a stabilizer.

Review on Polymer Electrolyte Membranes for Dye-sensitized Solar Cells (염료감응 태양전지용 고분자 전해질막의 총설)

  • Lee, Jae Hun;Park, Cheol Hun;Lee, Chang Soo;Kim, Jong Hak
    • Membrane Journal
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    • v.29 no.2
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    • pp.80-87
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    • 2019
  • Dye-sensitized solar cells (DSSCs) have attracted great attention as sustainable energy devices. The efficiency and long-term stability of DSSCs are greatly influenced by electrode materials and electrolytes. In this review, we focused on the electrolytes of DSSCs. Polymer electrolyte membranes have been proposed as an alternative to conventional liquid electrolytes in DSSCs. Conventional liquid electrolytes can exhibit a high efficiency, but due to some problems such as poor long-term stability of device and leakage of liquid, much interest in polymer electrolyte membranes continues to rise and the papers on polymer electrolytes membranes have been extensively reported recently. This review covers the concept and development of polymer electrolyte membranes for DSSCs, and discusses the efficiency and electrochemical properties of DSSCs, highlighting the modification of polymer matrix, the introduction of additives such as organic-inorganic plasticizers and ionic liquids.

Pore-network Study of Liquid Water Transport through Multiple Gas Diffusion Medium in PEMFCs (고분자 연료전지의 다공성층 내에서의 액상수분 이동에 관한 공극-네트워크 해석 연구)

  • Kang, Jung-Ho;Lee, Sang-Gun;Nam, Jin-Hyun;Kim, Charn-Jung
    • 한국전산유체공학회:학술대회논문집
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    • pp.46-53
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    • 2011
  • Water is continuously produced in polymer electrolyte membrane fuel cell (PEMFC), and is transported and exhausted through polymer electrolyte membrane (PEM), catalyst layer (CL), microporous layer (MPL), and gas diffusion layer (GDL). The low operation temperatures of PEMFC lead to the condensation of water, and the condensed water hinders the transport of reactants in porous layers (MPL and GDL). Thus, water flooding is currently one of hot issues that should be solved to achieve higher performance of PEMFC. This research aims to study liquid water transport in porous layers of PEMFC by using pore-network model, while the microscale pore structure and hydrophilic/hydrophobic surface properties of GDL and MPL were fully considered.

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Investigation of Water Transport in Newly Developed Micro Porous Layers for Polymer Electrolyte Membrane Fuel Cells

  • Alrwashdeh, Saad S.;Markotter, Henning;Haussmann, Jan;Hilger, Andre;Klages, Merle;Muller, Bernd R.;Kupsch, Andreas;Riesemeier, Heinrich;Scholta, Joachim;Manke, Ingo
    • 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.

A study on the application of Residential Polymer Electrolyte Membrane Fuel Cell (가정용 고분자 전해질 연료전지 시스템의 적용에 관한 연구)

  • Lee, Cheol-Ki;Kim, Ju-Young;Hong, Won-Hwa
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • pp.315-318
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    • 2005
  • One of the problems in using renewable energy sources is great difficulty of stable and sustainable supply. Because the fuel cell can provide stable and sustainable supply of energy sources without regard to external conditions, however, it will become one of the most useful renewable energy sources for buildings that need stable energy supply. For practical application of PEMFC system to common household, the data of household energy consumption are analyzed by electricity, cooking and heating. From the result of the data analysis, practical application methods of PEMFC system to household are designed to several models. The aim of this study is to establish a plan of practical application for applying Polymer Electrolyte Membrane Fuel Cell(PEMFC) system to the households.

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The Effect of Annealing on sSEBS/Polyrotaxanes Electrolyte Membranes for Direct Methanol Fuel Cells

  • Won, Jong-Ok;Cho, Hyun-Dong;Kang, Yong-Soo
    • Macromolecular Research
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    • v.17 no.10
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    • pp.729-733
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    • 2009
  • Solution casting films of sulfonated poly[styrene-b-(ethylene-r-butylene)-b-styrene] copolymer (sSEBS)-based composite membranes that contained different amounts of organic, nanorod-shaped polyrotaxane were annealed at various temperatures for 1 h. The films' properties were characterized with respect to their use as polymer electrolyte membranes in direct methanol fuel cells (DMFCs). Different aspect ratios of polyrotaxane were prepared using the inclusion-complex reaction between $\alpha$-cyclodextrin and poly(ethylene glycol). The presence of the organic polyrotaxane inside the membrane changed the morphology during the membrane preparation and reduced the transport of methanol. The conductivity and methanol permeability of the composite membranes decreased with increasing polyrotaxane content, while the annealing temperature increased. All of the sSEBS-based, polyrotaxane composite membranes annealed at $140^{\circ}C$ showed a higher selectivity parameter, suggesting their potential usage for DMFCs.