• Title/Summary/Keyword: polymer electrolyte membrane

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Development of Pore-filled Polymer Electrolyte Membranes for Flexible Electrochromic Devices (유연한 전기변색 소자를 위한 세공충진 고분자 전해질 멤브레인의 개발)

  • Park, Hyeon-Jung;Lee, Ji-Hyeon;Kang, Moon-Sung
    • Membrane Journal
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    • v.31 no.5
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    • pp.333-342
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    • 2021
  • A flexible electrochromic device (ECD) is a promising technology that is expected to be applied in various fields such as smart windows. Polymer electrolyte is an important component that determines the bleaching-coloration performance and physical stability of flexible ECDs. In this study, a pore-filled polymer electrolyte membrane (PFPEM) with excellent dimensional stability was developed to effectively fabricate flexible ECDs and improve durability. Polyvinyl acetate, which has excellent adhesion, and polyethylene glycol, which can improve ionic conductivity, were filled in the pores of a porous substrate made of polyethylene, which is inexpensive and has excellent physical and chemical stability. The optimal lithium salt (LiTFSI) content of the prepared PFPEM was determined at about 27 wt%, and it was confirmed to possess excellent dimensional stability, adhesive strength, and ion conductivity close to that of conventional polymer electrolytes. Although the visible light transmittance was lowered by the use of the porous substrate, it was expected to act as an advantage in the colored state.

Developing High-Performance Polymer Electrolyte Membrane Electrolytic Cell for Green Hydrogen Production (그린수소 생산을 위한 고성능 고분자 전해질막 전해조 개발 연구)

  • Choi, Baeck Beom;Jo, Jae Hyeon;Lee, Yae Rin;Kim, Jungsuk;Lee, Taehee;Jeon, Sang-Yun;Yoo, Young-Sung
    • KEPCO Journal on Electric Power and Energy
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    • v.7 no.1
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    • pp.137-143
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    • 2021
  • As an electrochemical water electrolysis for green hydrogen production, both polymer electrolyte membrane (PEM) and alkaline electrolyte are being developed extensively in various countries. The PEM electrolyzer with high current density (above 2 A/cm2) has the advantage of being able to design a simple structure. Also, it is known that it has high response to electrical output fluctuations. However, the cost problem of major components is the most important issue that a PEM electrolyzer must overcome. Instantly, there are platinum group metal (PGM)-based electrocatalysts, fluorine-based polyfluoro sulfuric acid (PFSA) membrane, Ti felt (porous transport layer, PTL) and so on. Another challenging issue is productivity. A securing outstanding productivity brings price benefits of the electrolytic cells. From this point of view, we conducted basic studies on manufacturing electrode and membrane electrode assembly (MEA) for PEM electrolyzer production.

Performance Evaluation of Platinum Dispersed Self-humidifying Polymer Electrolyte Membrane Prepared by Using RF Magnetron Sputter

  • Kwak, Sang-Hee;Yang, Tae-Hyun;Kim, Chang-Soo;Yoon, Ki-Hyun
    • Journal of the Korean Ceramic Society
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    • v.40 no.2
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    • pp.118-122
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    • 2003
  • The performance evaluation on Pt loading in the self-humidifying polymer electrolyte membrane for Polymer Electrolyte Mem-Brane Fuel Cell(PEMFC) was investigated by using single cell test and measurement of membrane resistance. The self-humidifying membrane comprised two membranes made of perfluorosulfonylfluroride copolymer resin and fine Pt particles tying between them, coated by sputtering. From the results of performance characteristics of self-humidifying membrane cell with different Pt loading, a single cell using self-humidifying membrane with 0.15 mg/$\textrm{cm}^2$ Pt loading showed better performance than that with the others over entire current density. Also, a single cell with 0.15 mg/$\textrm{cm}^2$ Pt loading had a lower resistance value than the other cells under externally nonhumidifying condition. It is indicated that the water produced in the membrane cell with 0.15 mg/$\textrm{cm}^2$ Pt loading showed a higher provision to maintain ionic conductivity of the membrane than the other cells. The optimum amount of Pt particles embedded in the membrane for self-humidifying PEMFC was determined to be about 0.15 mg/$\textrm{cm}^2$.

Effect of operating conditions on carbon corrosion in High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) (고온형 고분자 전해질막 연료전지(HT-PEMFC) 구동환경에 따른 탄소 담지체 부식 평가)

  • Lee, Jinhee;Kim, Hansung
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.89.1-89.1
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    • 2011
  • The influence of potential and humidity on the electrochemical carbon corrosion in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs) is investigated by measuring $CO_2$ emission at different potentials for 30 min using on-line mass spectrometry. These results are compared with low tempterature polymer electrolyte membrane fuel cells(LT-PEMFCs) operated at lower temperature and higher humidity condition. Although the HT-PEMFC is operated at non humidified condition, the emitted $CO_2$ in the condition of HT-PEMFC is more than LT-PEMFC at the same potential in carbon corrosion test. Thus, carbon corrosion shows a stronger positive correlation with the cell temperature. In addition, the presence of a little amount of water activate electrochemical carbon corrosion considerably in HT-PEMFC. With increased carbon corrosion, changes in fuel cell electrochemical characteristics become more noticeable and thereby indicate that such corrosion considerably affects fuel cell durability.

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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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    • 2005.06a
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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.

Electrospun Poly(Ether Sulfone) Membranes Impregnated with Nafion for High-Temperature Polymer Electrolyte Membrane Fuel Cells

  • Lee, Hong Yeon;Hwang, Hyung Kwon;Lee, Jin Goo;Jeon, Yukwon;Park, Dae-Hwan;Kim, Jong Hak;Shul, Yong-Gun
    • Journal of the Korean Electrochemical Society
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    • v.19 no.1
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    • pp.9-13
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    • 2016
  • Electrospun poly(ether sulfone) (PES) membrane impregnated with Nafion (PES-N) have been developed for high-temperature polymer-electrolyte membrane fuel cell (HT-PEMFC). The PES-N obtains highly thermal stability up to $430^{\circ}C$, which is higher than that of the commercial Nafion 212. The PES-N membrane shows a good proton conductivity of about $10^{-2}S\;cm^{-1}$ in a temperature range from $75^{\circ}C$ to $120^{\circ}C$. The membrane-electrode assembly (MEA) with the PES-N membrane exhibits a current density of $1.697A\;cm^{-2}$ at $75^{\circ}C$, and $0.813A\;cm^{-2}$ at $110^{\circ}C$ when the applied voltage is 0.6 V, whereas the MEA with the Nafion 212 membrane shows the current density of $0.647Acm^{-2}$ at $110^{\circ}C$. The results suggest that the PES-N can be a good candidate for a polymer electrolyte membrane of the HT-PEMFC.

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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    • 2003.07a
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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.