• Title, Summary, Keyword: Polymer electrolyte membrane

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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.

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.

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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Performance Analysis of Polymer Electrolyte Membrane Fuel Cell by AC Impedance Measurement (교류 임피던스 측정법을 이용한 고분자 전해질 연료전지의 성능특성 분석)

  • Seo, Sang-Hern;Lee, Chang-Sik
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.4
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    • pp.283-290
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    • 2009
  • This study focuses on the performance characteristics of polymer electrolyte membrane fuel cell (PEMFC) using the AC impedance technique. The experiment was carried out to investigate the optimal operating conditions of PEMFC such as cell temperature, flow rate, humidified temperature and back-pressure. The fuel cell performance was analyzed by DC electronic-loader with constant voltage mode and expressed by voltage-current density. Additionally, AC impedance was measured to analysis of ohmic and activation loss and expressed by Nyquist plot. The results showed that the cell performance increased with increase of cell temperature, air flow rate, humidified temperature and backpressure. Also, the activation loss decreased as the increase of cell temperature, air flow rate, humidified temperature and backpressure.

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.

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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Polymer Electrolyte Membranes and their Applications to Membranes, Fuel Cells and Solar Cells

  • Kang, Yong-Soo
    • Proceedings of the Membrane Society of Korea Conference
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    • pp.29-32
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    • 2003
  • Polymer electrolyte membranes are developed for the applications to facilitated transport membranes, fuel cells and solar cells. The polymer electrolyte membranes containing silver salt show the remarkably high separation performance for olefin/paraffin mixture in the solid state; the propylene permeance is 45 GPU and the ideal selectivity of propylene/propane is 15,000. For fuel cell membranes, the effects of the presence and size of the proton transport channels on the proton conductivity and methanol permeability were investigated. The cell performance for dye-sensitized solar cells employing polymer electrolytes are measured under light illumination. The overall energy conversion efficiency reaches 5.44 % at 10 ㎽/$\textrm{cm}^2$, to our knowledge the highest value ever reported in the polymer electrolytes.

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Characterization of DNA/Poly(ethylene imine) Electrolyte Membranes

  • Park, Jin-Kyoung;Won, Jong-Ok;Kim, Chan-Kyung
    • Macromolecular research
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    • v.15 no.6
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    • pp.581-586
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    • 2007
  • Cast DNA/polyethyleneimine (PEI) blend membranes containing different amounts of DNA were prepared using acid-base interaction and characterized with the aim of understanding the polymer electrolyte membrane properties. Two different molecular weights of PEI were used to provide the mechanical strength, while DNA, a polyelectrolyte, was used for the proton transport channel. Proton conductivity was observed for the DNA/PEI membrane and reached approximately $3.0{\times}10^{-3}S/cm$ for a DNA loading of 16 wt% at $80^{\circ}C$. The proton transport phenomena of the DNA/PEI complexes were investigated in terms of the complexation energy using the density functional theory method. In the case of DNA/PEI, a cisoid-type complex was more favorable for both the formation of the complex and the dissociation of hydrogen from the phosphate. Since the main requirement for proton transport in the polymer matrix is to dissociate the hydrogen from its ionic sites, this suggests the significant role played by the basicity of the matrix.

Decrease in hydrogen crossover through membrane of polymer electrolyte membrane fuel cells at the initial stages of an acceleration stress test

  • Hwang, Byung Chan;Oh, So Hyeong;Lee, Moo Seok;Lee, Dong Hoon;Park, Kwon Pil
    • The Korean Journal of Chemical Engineering
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    • v.35 no.11
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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.