• Title/Summary/Keyword: Polymer electrolyte membrane

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Carbon-Supported Ordered Pt-Ti Alloy Nanoparticles as Durable Oxygen Reduction Reaction Electrocatalyst for Polymer Electrolyte Membrane Fuel Cells

  • Park, Hee-Young;Jeon, Tae-Yeol;Lee, Kug-Seung;Yoo, Sung Jong;Sung, Young-Eun;Jang, Jong Hyun
    • Journal of Electrochemical Science and Technology
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    • v.7 no.4
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    • pp.269-276
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    • 2016
  • Carbon-supported ordered Pt-Ti alloy nanoparticles were prepared as a durable and efficient oxygen reduction reaction (ORR) electrocatalyst for polymer electrolyte membrane fuel cells (PEMFCs) via wet chemical reduction of Pt and Ti precursors with heat treatment at $800^{\circ}C$. X-ray diffraction analysis confirmed that the prepared electrocatalysts with Ti precursor molar compositions of 40% (PtTi40) and 25% (PtTi25) had ordered $Pt_3Ti$ and $Pt_8Ti$ structures, respectively. Comparison of the ORR polarization before and after 1500 electrochemical cycles between 0.6 and 1.1 V showed little change in the ORR polarization curve of the electrocatalysts, demonstrating the high stability of the PtTi40 and PtTi25 alloys. Under the same conditions, commercial carbon-supported Pt nanoparticle electrocatalysts exhibited a negative potential shift (10 mV) in the ORR polarization curve after electrochemical cycling, indicating degradation of the ORR activity.

Current Status of One-Dimensional Nanostructured Catalysts for Polymer Electrolyte Membrane Fuel Cell (고분자 전해질 막 연료 전지용 1차원 나노 구조 촉매의 연구 현황)

  • Jeon, Kiung;Jung, Yeon Sik
    • Ceramist
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    • v.21 no.4
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    • pp.331-348
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    • 2018
  • With the expectation to overcome the problem of increasing energy consumption, polymer electrolyte membrane fuel cells are getting more attention as a promising environmentally friendly and sustainable next-generation energy conversion system. In spite of the rapid improvement of polymer electrolyte membrane fuel cells(PEMFCs), there are several critical issues still need to be resolved for practical commercialization. Out of the many issues, the main hurdle comes from oxygen reduction reaction(ORR), thus development of efficient ORR electrocatalysts is the main key for enhancing PEMFC performance. Among various catalysts, 1D nanostructured catalyst is a promising candidate because it holds many advantages that come from nanostructuring while supplementing the disadvantages of other nanostructures such as nanoparticles(0D) or gyroids(3D). This review focused on diverse 1D nanostructures and talks about their advantages as catalyst for ORR. Different 1D nanostructures will be introduced while applying the structures to different materials system showing the prospects of 1D nanostructures for improving PEMFC.

High Performance Electrode of Polymer Electrolyte Membrane Fuel Cells Prepared by Direct Screen Printing Process (직접 스크린 프린팅법으로 제조된 고분자 전해질 연료전지의 고성능 전극)

  • 임재욱;최대규;류호진
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.1
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    • pp.65-69
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    • 2004
  • Screen printing it one of the most popular methods for the fabrication of catalytic layer in electrode of polymer electrolyte membrane fuel cells (PEMFCs) due to its convenience and adaptability. This paper suggests an improved screen-printing method, which is rather simple suppressing the swelling trouble without additive process and competitive with very low Pt loading in comparison with the previous methods. Particularly, the gasket unified MEA made better performances than the other especially at high current area due to blocking effect on the gas leakage during the operation. These methods give us more simplified and faster fabrication chances.

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SIMULATION OF UNIT CELL PERFORMANCE IN THE POLYMER ELECTROLYTE MEMBRANE FUEL CELL

  • Kim, H.G.;Kim, Y.S.;Shu, Z.
    • International Journal of Automotive Technology
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    • v.7 no.7
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    • pp.867-872
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    • 2006
  • Fuel cells are devices that convert chemical energy directly into electrical energy. Owing to the high efficiency of the fuel cells, a large number of research work have been done during these years. Among many kinds of the fuel cells, a polymer electrolyte membrane fuel cell is such kind of thing which works under low temperature. Because of the specialty, it stimulated intense global R&D competition. Most of the major world automakers are racing to develop polymer electrolyte membrane fuel cell passenger vehicles. Unfortunately, there are still many problems to be solved in order to make them into the commercial use, such as the thermal and water management in working process of PEMFCs. To solve the difficulites facing the researcher, the analysis of the inner mechanism of PEMFC should be implemented as much as possible and mathematical modeling is an important tool for the research of the fuel cell especially with the combination of experiment. By regarding some of the assumptions and simplifications, using the finite element technique, a two-dimensional electrochemical mode is presented in this paper for the further comparison with experimental data. Based on the principals of the problem, the equations of electronic charge conservation equation, gas-phase continuity equation, and mass balance equation are used in calculating. Finally, modeling results indicate some of the phenomenon in a unit cell, and the relationships between potential and current density.

Development and Characterization of Polymer Electrolyte Membranes Containing Polysilsesquioxane Spheres (Polysilsesquioxane 구를 함유하는 고분자 전해질 막 제조 및 특성 연구)

  • Hong Seong Uk;Cheon Hun Sang;Kim Young Baik;Park Hun Hwee
    • Membrane Journal
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    • v.15 no.1
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    • pp.1-7
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    • 2005
  • Polymer electrolyte membranes containing polysilsesquioxane (PSQ) spheres were prepared with the blend of sulfonated poly(ether ether ketone) (SPEEK) (60%) and poly(ether sulfone) (PES) (40%). The amount of PSQ spheres was fixed at 10 wt%. The prepared polymer electrolyte membranes were characterized in terms of methanol permeability, proton conductivity, and ion exchange capacity. In all cases, both methanol permeability and proton conductivity of the polymer electrolyte membranes containing PSQ spheres were lower than the values of Nafion 117 and higher than those of SPEEK/PES (6:4) blend without PSQ spheres. The experimental results indicated that the polymer electrolyte membranes containing MS64 and VTMOS spheres were the best choice in terms of the ratio of proton conductivity to methanol permeability.

Electrospun $SiO_2$ membrane using covalently cross-linked SPEEK/HPA by impregnation for high temperature PEMFC

  • Na, Heesoo;Hwang, Hyungkwon;Lee, Chanmin;Shul, Yonggun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.85.2-85.2
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    • 2010
  • There is widespread effort to develop polymer membranes in place of Nafion for high temperature polymer electrolyte membrane fuel cell(PEMFC). In our study, SiO2 membranes are arranged by electrospinning method. For impregnation solution, the modified sulfonated poly(ether ether ketone)(SPEEK) polymer is prepared from sulfonation, sulfochlorination, partial reduction and lithiation reaction. The modified polymer is cross-linked with 1,4-diiodobetane in NMP solvent and then blended with Heteropoly acid(HPA). The characterization of membranes is confimed by FT-IR, Thermogravimetry(TGA), water uptake test and single cell performance test for PEMFC, etc. The composite membrane shows satisfactory thermal and mechanical properties. Beside, The membrane exhibits good ion exchange capacity and high proton conductivity. As a result, The composite membrane is promising as an alternative membrane in high temperature PEMFC.

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Study on Pressurized Diesel Reforming System for Polymer Electrolyte Membrane Fuel Cell in Underwater Environment (수중 환경에서 고분자 전해질 연료전지(PEMFC) 공급용 수소 생산을 위한 가압 디젤 개질시스템에 관한 연구)

  • Lee, Kwangho;Han, Gwangwoo;Bae, Joongmyeon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.4
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    • pp.528-535
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    • 2017
  • Fuel cells have been spotlighted in the world for being highly efficient and environmentally friendly. A hydrogen which is the fuel of fuel cell can be obtained from a number of sources. Hydrogen source for operating the polymer electrolyte membrane fuel cell(PEMFC) in the current underwater environment, such as a submarine and unmanned underwater vehicles are currently from the metal hydride cylinder. However, metal hydride has many limitations for using hydrogen carrier, such as large volume, long charging time, limited storage capacity. To solve these problems, we suggest diesel reformer for hydrogen supply source. Diesel fuel has many advantages, such as high hydrogen storage density, easy to transport and also well-infra structure. However, conventional diesel reforming system for PEMFC requires a large volume and complex CO removal system for lowering the CO level to less than 10 ppm. In addition, because the preferential oxidation(PROX) reaction is the strong exothermic reaction, cooling load is required. By changing this PROX reactor to hydrogen separation membrane, the problem from PROX reactor can be solved. This is because hydrogen separation membranes are small and permeable to pure hydrogen. In this study, we conducted the pressurized diesel reforming and water-gas shift reaction experiment for the hydrogen separation membrane application. Then, the hydrogen permeation experiments were performed using a Pd alloy membrane for the reformate gas.