• Title, Summary, Keyword: Proton conductivity

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Titanium Dioxide Nanoparticles filled Sulfonated Poly(ether ether ketone) Proton Conducting Nanocomposites Membranes for Fuel Cell

  • Kalappa, Prashantha;Hong, Chang-Eui;Kim, Sung-Kwan;Lee, Joong-Hee
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.87-90
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    • 2005
  • This paper presents an evaluation of the effect of titanium dioxide nanoparticles in sulfonated poly(ether ether ketone) (SPEEK) with sulfonation degree of 57%. A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxide nanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of temperature were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with standard nafion membrane.

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Fabrication of $SrZrO-3$-based Proton Conductors and Their Characterization

  • Yoo, Kwang-Soo;Byun, Douck-Young
    • The Korean Journal of Ceramics
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    • v.7 no.2
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    • pp.93-96
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    • 2001
  • The Y- or Yb-doped SrZrO$_3$ proton conductors were fabricated using the powders prepared by the self-propagating high-temperature synthesis (SHS). The electrical conductivity was evaluated from an a.c. impedance measurements. The conductivity of SrZr$_{0.92}$Yb$_{0.08}$O$_{3-\delta}$ was 1.8$\times$10$^{-3}$ Scm$^{-1}$ at $900^{\circ}C$ in dry air atmosphere and its activation energy was 0.50 eV. The conductivity in wet air was larger, compared with the dry air, and the activaton energy of SrZr$_{0.92}$Yb$_{0.08}$O$_{3-\delta}$ in wet air was 0.40 eV.

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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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    • 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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Preparation and Their Characterization of Blended Polymer Electrolyte Membranes of Polysulfone and Sulfonated Poly(ether ether ketone) (Polysulfone/SPEEK 블랜드 고분자 전해질 막 제조 및 특성 연구)

  • Cheon, Hun-Sang;Oh, Min;Hong, Seong-Uk
    • Membrane Journal
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    • v.13 no.1
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    • pp.47-53
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    • 2003
  • Poly(ether ether ketone)(PEEK) was sulfonated using sulfuric acid and blended with polysulfone with various ratios. The blended polymer electrolyte membranes were characterized in terms of methanol permeability, proton conductivity and ion exchange capacity. As the amount of sulfonated PEEK increased, both methanol permeability and proton conductivity increased. This was due to the increase of ion exchange capacity. The experimental results indicated that the blend membrane with 20% polysulfone was the best choice In terms of the ratio of proton conductivity to methanol permeability.

Effect of the Molecular Weight of Poly(vinyl alcohol) Blended with Sulfonated Polysulfone Membranes for Fuel Cell Applications

  • Chang, Sung-Hyuk;Chung, Sung-Il;Rhim, Ji-Won
    • Korean Membrane Journal
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    • v.5 no.1
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    • pp.18-24
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    • 2003
  • In order to improve the mechanical properties of the sulfonated polysulfone (SPSf) membranes previously synthesized in our laboratory, poly(vinyl alcohol) (PVA) was blended which is well known as the excellent physical and chemical properties. The resulting membranes blended with several molecular weight of PVA varying from 13,000 to 124,000 have been characterized to investigate the effect of PVA molecular weight in terms of ion conductivities, methanol permeabilities, water contents and ion exchange capacities for both heat treated and untreated membranes at 150$^{\circ}C$. The proton conductivity is decreased as the molecular weight of PVA increases. The plain SPSf-6.0 showed the proton conductivity of 0.078 S/cm whereas the blended membrane with M.W. 31,000 PVA indicated 0.04 S/cm. For methanol permeabilities, when PVA is added to SPAf-6.0, methanol crossover is increased because of the gain of the hydrophilicity from 3.4 to 6.5${\times}$10$\^$-6/ $\textrm{cm}^2$/s. For the annealed blended membranes (with M.W. 31,000 PVA), both the methanol corssover and proton conductivity showed very consistent values, about 2.3${\times}$10$\^$-6/ $\textrm{cm}^2$/s and 0.036 S/cm, respectively.

The Effect of sGO Content in sPEEK/sGO Composite Membrane for Unitized Regenerative Fuel Cell (일체형 재생연료전지 적용을 위한 sGO 함량 변화에 따른 sGO/sPEEK 복합막의 특성 평가)

  • Jung, Ho-Young;Kim, Min-Woo;Lim, Ji-Hun;Choi, Jin H.;Roh, Sung-Hee
    • KEPCO Journal on Electric Power and Energy
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    • v.2 no.1
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    • pp.127-131
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    • 2016
  • Polymer electrolyte membrane for unitized regenerative fuel cells requires high proton conductivity, high dimensional stability, low permeability, and low cost. However, DuPont's Nafion which is a commercial polymer electrolyte membrane has high permeability, high cost, and decreasing proton conductivity and dimensional stability over $80^{\circ}C$. To address these problems, sulfonated poly ether ether ketone (sPEEK) which is a low cost hydrocarbon polymer is selected as matrix polymer for the preparation of polymer electrolyte membrane. In addition, composite membrane with improved proton conductivity and dimensional stability is prepared by introducing sulfonated graphene oxide (sGO). The fundamental properties of polymer electrolyte membranes are analyzed by investigating membrane's water content, dimensional stability, proton conductivity, and morphology. The cell test is conducted to consider the possibility of application of sPEEK/sGO composite membrane for an unitized regenerative fuel cell.

The Fabrication of BaZrO3-based Proton Conductors and their Electrical Properties by Dopants (BaZrO3계 수소이온 전도체의 제조 및 첨가물에 따른 전기적 특성)

  • 권정범;유광수
    • Journal of the Korean Ceramic Society
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    • v.40 no.5
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    • pp.415-422
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    • 2003
  • BaZr $O_3$-based proton conductors in which B-site cations are partially substituted by Ce and Yb were fabricated by a solid state reaction method. The electrical properties of the specimens were measured by using impedance analyzer in dry air and wet air atmospheres. The electrical conductivity showed higher value in wet air than in dry air at below $600^{\circ}C$. As the Ce content increased, the electrical conductivity increased. Among four compositions, BaZ $r_{0.8}$C $e_{0.15}$Y $b_{0.05}$ $O_3$$_{-{\delta}}$ specimen showed the highest electrical conductivity,1.72$\times$10$^{-3}$ S$cm^{-1}$ /, at 80$0^{\circ}C$. In the low temperature region, the electrical conductivity was higher in wet air than in dry air. However, as the temperature increased, the proton conductivity reduced and thus the electrical conductivity showed similar value at approximately $700^{\circ}C$.

Defect Structure and Electrical Conductivities of $SrCe_{0.95}Yb_{0.05}O_3$ ($SrCe_{0.95}Yb_{0.05}O_3$의 결함엄개와 전기전도 특성)

  • 최정식;이도권;유한일
    • Journal of the Korean Ceramic Society
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    • v.37 no.3
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    • pp.271-279
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    • 2000
  • 5 m/o Yb-doped SrCeO3 proton conductor was prepared by a solid state reaction method and its total electriccal conductivity measured as a function of both oxygen partial pressure and water vapor partial pressure in the temperature range of 500~100$0^{\circ}C$. From the total conductivity have been deconvoluted the partial conductivities of oxide ions, protons, and holes, respectively, on the basis of the defect model proposed. The equilibrium constant of hydrogen-dissolution reaction, proton concentration, and mobilities of oxygen vacancies and protons have subsequently been evaluated. It is verified that SrCe1-xYbxO3 is a mixed conductor of holes, protons and oxide ions and the proton conduction prevails as temperature decreases and water vapor pressure increases. The heat of water dissolution takes a representative value of $\Delta$HoH=-(140$\pm$20) kJ/mol-H2O, but tends to be less negative with increasing temperature. Migration enthalpies of proton and oxygen vacancy are extracted as 0.83$\pm$0.10 eV and 0.81$\pm$0.01 eV, respectively.

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Proton Conductivity and Methanol Permeability of Sulfonated Polysulfone/PPSQ Composite Polymer Electrolyte Membrane (설폰화된 폴리설폰/PPSQ 유-무기 복합 전해질막의 수소이온 전도도 및 메탄올 투과 특성)

  • Kwon Jeongdon;Lee Changjin;Kang Yongku
    • Journal of the Korean Electrochemical Society
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    • v.7 no.2
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    • pp.89-93
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    • 2004
  • Sulfonated polysulfone (SPSF) with poly(phenylmethyl silsesquioxane, PPSQ) composite polymer electrolyte membranes were prepared and their proton conductivity, water uptake and methanol permeability of membranes were characterized. By controlling the ratio of $(CH_3)_3SCI\;and\;CISO_3H$ and reaction time, SPSF with $37\~75\%$ degree of sulfonation were synthesized. The increase of sulfonate groups in the base polymer resulted in the increase of the water uptake in the membranes as well as methanol permeability. Composite membranes were prepared by casting of DMF solution of SPSF and PPSQ. The proton conductivity of the composite membrane at room temperature was $2.8\times10^{-3}\~4.9\times10^{-2}S/cm.$ The increase of PPSQ contents in composite membranes resulted in a decrease in water uptake and methanol permeability. Composite membranes containing $5\%$ PPSQ did not make a significant effect on the proton conductivity nO methanol permeability compared with that of pristine SPSF, but a significant decrease of water uptake was observed.