• Title/Summary/Keyword: Phosphoric acid doped membrane

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Phosphoric Acid-doped SDF-F/poly(VI-co-MPS)/PTFE Membrane for a High Temperature Proton Exchange Membrane Fuel Cell

  • Lee, Jong-Won;Yi, Cheol-Woo;Kim, Keon
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1902-1906
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    • 2011
  • Sulfonated poly(fluorinated arylene ether)s (SDF-F)/poly[(N-vinylimidazole)-co-(3-methacryloxypropyl-trimethoxysilane)] (poly(VI-co-MPS))/poly(tetrafluoroethylene) (PTFE) is prepared for a high temperature proton exchange membrane fuel cell (PEMFC). The reaction of the membrane with phosphoric acid forms silicate phosphor, as a chemically bound proton carrier, in the membrane. Thus-formed silicate phosphor, nitrogen in the imidazole ring, and physically bound phosphoric acid act as proton carriers in the membrane. The physico-chemical and electrochemical properties of the membrane are investigated by various analytical tools. The phosphoric acid uptake and proton conductivity of the SDF-F/poly(VI-co-MPS)/PTFE membrane are higher than those of SDF-F/PVI/PTFE. The power densities of cells with SDF-F/poly(VI-co-MPS)/PTFE membranes at 0.6 V are 286, 302, and 320 mW $cm^{-2}$ at 150, 170, and 190 $^{\circ}C$, respectively. Overall, the SDFF/poly(VI-co-MPS)/PTFE membrane is one of the candidates for anhydrous HT-PEMFCs with enhanced mechanical strength and improved cell performance.

Synthesis and Characterization of Polybenzimidazole Random Copolymers Containing Methylene Chain for High Temperature PEMFC (고온 PEMFC용 메틸렌 사슬을 포함하는 폴리벤즈이미다졸 랜덤 공중합체의 합성과 특성 분석)

  • HAN, DAEUN;YOO, DONG JIN
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.6
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    • pp.578-586
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    • 2018
  • In this study, we prepared the modified PBI random copolymer to reduce the problems of the pristine PBI about low solubility and proton conductivity. The random copolymer was synthesized from suberic acid, 5-aminoisophthalic acid, and 3,3'-diaminobenzidine to obtain $X_1Y_9$, $X_1Y_1$, $X_9Y_1$. Then, the membrane was fabricated by using solvent casting method with methanesulfonic acid at $140^{\circ}C$. Subsequently, the membrane was doped with phosphoric acid at $40^{\circ}C$. The chemical structure of the polymers was characterized by FT-IR. In addition, the physiochemical properties of the PBI were investigated by TGA, oxidative stability, acid uptake. Finally, the proton conductivity was measured at $100-180^{\circ}C$ without humidification. As the result, $X_1Y_9$ PBI random copolymer membrane showed higher conductivity.

Synthesis and Characterization of Polybenzimidazoles Containing Perfluorocyclobutane Groups for High-temperature Fuel Cell Applications

  • Chang, Bong-Jun;Kim, Dong-Jin;Kim, Jeong-Hoon;Lee, Soo-Bok;Joo, Hyeok-Jong
    • Korean Membrane Journal
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    • v.9 no.1
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    • pp.43-51
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    • 2007
  • This paper describes the preparation and characterization of two kinds of fluorinated polybenzimidazole (PBI)s which can be potentially used for phosphoric acid-doped, high-temperature polymer electrolyte membrane fuel cells. Two kinds of perfluorocyclobutane (PFCB)-containing monomers were prepared via following synthetic steps; after fluoroalkylation of methyl 3-(hydroxy) benzoate and methyl 4-(hydroxy) benzoate with 1,2-dibromotetrafluoroethane and subsequent Zn-mediated dehalogenation, these compounds were cyclodimerized at $200^{\circ}C$ affording the ester-terminated monomers containing PFCB ether groups. The synthesized intermediates and monomers were characterized using FT-IR, $^1H-NMR,\;^{19}F-NMR$, and mass spectroscopy. The fluorinated PBIs were then successfully prepared through the solution polycondensation of the monomers and 3,3'-diaminobenzidine in polyphosphoric acid. Compared with traditional PBI, the glass transition temperatures of the fluorinated PBIs were obtained at $262^{\circ}C\;and\;269^{\circ}C$ which are lower than that of PBI and their initial degradation temperatures were still high over $400^{\circ}C$ under nitrogen. The fluorinated PBIs showed higher d-spacing values and improved solubility in several organic solvents as well as phosphoric acid, which confirmed they could be good candidates for the high temperature fuel cell membranes.

Synthesis and Characterization of Phosphoric Acid-doped Poly (2,5-benzimidazole) Membrane for High Temperature Polymer Electrolyte Membrane Fuel Cells (고온 고분자 연료전지용 인산 도핑 폴리(2,5-벤지이미다졸) 막의 제조 및 특성)

  • Nguyen, Thi Xuan Hien;Mishra, Ananta Kumar;Choi, Ji-Sun;Kim, Nam-Hoon;Lee, Joong-Hee
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.1
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    • pp.26-33
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    • 2012
  • Phosphoric acid-doped poly (2,5-benzimidazole) (DABPBI) was prepared by condensation polymerization of 3,4-diaminobenzoic acid for high temperature proton electrolyte membrane fuel cells. The membranes were casted directly using a hot-press unit and characterized by fourier transform infrared spectroscopy, thermogravimetric analysis, conductivity measurement, scanning electron microscopy and tensile test. The proton conductivities of DABPBI are observed to be 0.062 and 0.018 $S{\cdot}cm^{-1}$ under 30 and 1% relative humidity, respectively at a temperature of $120^{\circ}C$ which is appreciably higher than that of Nafion 115 under similar conditions. The DABPBI membrane has demonstrated excellent thermo- mechanical properties and proton conductivity suggesting its suitability as a high temperature membrane.

Synthesis and Properties of New Type of Proton Conducting Polymer Membrane for High Temperature Fuel Cells (고온 연료전지용 새로운 형태의 고분자 전해질막의 합성과 특성연구)

  • Lee, Joong-Hee;Sambhu, Bhadra;Kim, Nam-Hoon;Lee, Hong-Ki;Kim, Hong-Gun
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.166-169
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    • 2009
  • Poly(benzimidazole-co-aniline) (PBIANI), a self-crosslinked, net-structured, proton conducting polymer has been synthesized for the membrane of high temperature proton exchange membrane fuel cells (HT-PEMFC) with improved proton conductivity and mechanical strength. The stress at break (26$\pm$3MPa)and proton conductivity (167 mS cm-1)of the phosphoric acid doped PBIANI (DPBIANI)membrane is much higher than those of other doped polybenzimidazole(PBI) type membranes.

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The Electrochemical Performance Evaluation of PBI-based MEA with Phosphoric Acid Doped Cathode for High Temperature Fuel Cell (인산 도핑 PBI계 막전극접합체를 적용한 고온형 수소연료전지의 전기화학적 내구성 연구)

  • RHEE, JUNKI;LEE, CHANMIN;JEON, YUKWON;LEE, HONG YEON;PARK, SANG SUN;KIM, TAE YOUNG;KIM, HEESEON;SONG, SOONHO;PARK, JUNG OCK;SHUL, YONG-GUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.5
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    • pp.471-480
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    • 2017
  • A proton exchange membrane fuel cell (PEMFC) operated at $150^{\circ}C$ was evaluated by a controlling different amount of phosphoric acid (PA) to a membrane-electrode assembly (MEA) without humidification of the cells. The effects on MEA performance of the amount of PA in the cathode are investigated. The PA content in the cathodes was optimized for higher catalyst utilization. The highest value of the active electrochemical area is achieved with the optimum amount of PA in the cathode confirmed by in-situ cyclic voltammetry. The current density-voltage experiments (I-V curve) also shows a transient response of cell voltage affected by the amount of PA in the electrodes. Furthermore, this information was compared with the production variables such as hot pressing and vacuum drying to investigate those effect to the electrochemical performances.

Preparation and Characterization of the $H_3PO_4$-doped Sulfonated Poly(aryl ether benzimidazole) Membrane for Polymer Electrolyte Membrane Fuel Cell (고분자전해질 연료전지용 인산 도핑 술폰화 폴리아릴에테르벤즈이미다졸 고분자전해질 막의 제조 및 특성)

  • Hong, Young-Taik;Jeong, Jin-Ju;Yoon, Kyung-Sock;Choi, Jun-Kyu;Kim, Young-Jun
    • Membrane Journal
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    • v.16 no.4
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    • pp.276-285
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    • 2006
  • Acid-doped sulfonated poly(aryl ether benzimidazole) (S-PAEBI) copolymers were synthesized by a direct polymerization technique and a doping with phosphoric acid as a dopant, and the polymer electrolyte membranes were fabricated from them by a solution casting method. To optimize the reaction condition, the degree of sulfonation and doping level were varied in the ranges of $0{\sim}60%\;and\;0.7{\sim}5.7$, respectively. Physiochemical properties of the doped membranes were investigated by AFM, TGA and the measurement of proton conductivity. It was found that proton conductivities depend on doping levels of membranes. Conductivity determined at the condition of $130^{\circ}C$ and no humidity was $7.3{\times}10^{-2}S/cm$ for the $H_3PO_4$-doped PAEBI membrane with a doping level of 5.7.

Operating Method to Maximize Life Time of 5 kW High Temperature Polymer Exchange Membrane Fuel Cell Stack (5 kW 고온 고분자연료전지 스택 수명 극대화를 위한 운전 방법론)

  • KIM, JIHUN;KIM, MINJIN;SOHN, YOUNG-JUN;YU, SANGSEOK
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.2
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    • pp.144-154
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    • 2016
  • HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) using PA (phosphoric acid) doped PBI (polybenzimidazole) membrane has been researched for extending the lifetime. However, the existing work on durability of HT-PEMFC focuses on identifying degradation causes of lab scale. The short life time of HT-PEMFC is still the problem for its commercialization. In this paper, an operating method to maximize life time of 5kW HT-PEMFC stack are proposed. The proposed method includes major steps such as minimization of OCV (Open Circuit Voltage) exposure, control of the proper stack temperature, and N2 purging for the stack. This long life operating method was based on the fragmentary results of degradation from previous research works. Experimentally, the 5 kW homemade HT-PEMFC stack was operated for a long time based on the proposed method and the stack successfully can operate within the desired degradation rate for the target life time.

Inorganic-organic Hybrid Proton Conductive Membranes Doped with Phosphoric Acid

  • Huang Sheng-Jian;Lee Yong Su;Lee Hoi Kwn;Kang Won Ho
    • Proceedings of the KAIS Fall Conference
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    • 2004.06a
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    • pp.96-99
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    • 2004
  • A new proton conductive inorganic-organic hybrid membrane doped with $H_3PO_4$ was fabricated via sol-gel process wit 3- glycidoxypropyltrimethoxysilane(GPTMS), 3-aminopropyltriethoxysilane(APTES) and tetraethoxysilane(TEOS) asprecursors. Theproto conductivity of about 3.0$\times10^{-3}S/cm$ was obtained at $120^{\circ}C$ under $50\%$ relative humidity (R.H). DTA curves showed that the thermal stability of the membrane is significantly enhanced by the presence of $SiO_2$ framework up to $250^{\circ}C$. SEM and XRD revealed that the gel is microporou and amorphous. The addition of APTES improved the conductivity of the membranes and the effect of the APTES on the conductivity was also discussed in this paper.

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Analysis of Thermal Effect by Coolant Plate Number in High-Temperature Polymer Electrolyte Membrane Fuel Cell Stack (고온형 고분자 전해질 연료전지 스택 내부의 냉각판 수가 스택에 미치는 열 영향성의 수치적 연구)

  • Choi, Byung Wook;Ju, Hyun Chul
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.2
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    • pp.127-135
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    • 2015
  • High-Temperautre Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) with phosphoric acid-doped polybenzimidazole (PBI) membrane has high power density because of high operating temperature from 100 to $200^{\circ}C$. In fuel cell stack, heat is generated by electrochemical reaction and high operating temperature makes a lot of heat. This heat is caouse of durability and performance decrease about stack. For these reasons, heat management is important in HT-PEMFC. So, we developed HT-PEMFC model and study heat flow in HT-PEMFC stack. In this study, we placed coolant plate number per cell number ratio as variable and analysed heat flow distribution in stack.