Proton exchange membranes based on the short-side-chain perfluorinated ionomer for high temperature direct methanol fuel cells (original) (raw)
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The application of Dow Chemical's perfluorinated membranes in proton-exchange membrane fuel cells
Journal of Power Sources, 1990
Dow Chemical's research activities in fuel cells revolve around the development of perfluorosulfonic acid membranes, useful as the proton transport medium and separator. The following work will outline some of the performance characteristics which are typical for such membranes. 0378-7753/90/$3.50 @ Elsevier Sequoia/Printed in The Netherlands 2 B. R. Ezzell, B. Carl and W. A. Mod, Ion exchange membranes for the chlor-alkali industry, AIChE Symp. Series, Houston, TX, March 1985, pp. 49 -51. 3 G. A. Eisman, The physical and mechanical properties of a new perfluorosulfonic acid ionomer for use as a separator/membrane in proton exchange processes, Proc. 136th Electrochem. Sot. Meeting, Boston, MA, May 1986. 4 G. A. Eisman, The application of a new perfluorosulfonic acid ionomer in protonexchange membrane fuel cells: new ultra-high current density capabilities, Ext.
International Journal of Hydrogen Energy, 2014
We report on polymer electrolyte membrane fuel cells (PEMFCs) that function at high temperature and low humidity conditions based on short-side-chain perfluorosulfonic acid ionomer (SSC-PFSA). The PEMFCs fabricated with both SSC-PFSA membrane and ionomer exhibit higher performances than those with long-side-chain (LSC) PFSA at temperatures higher than 100 C. The SSC-PFSA cell delivers 2.43 times higher current density (0.524 A cm À1) at a potential of 0.6 V than LSC-PFSA cell at 140 C and 20% relative humidity (RH). Such a higher performance at the elevated temperature is confirmed from the better membrane properties that are effective for an operation of high temperature fuel cell. From the characterization technique of TGA, XRD, FT-IR, water uptake and tensile test, we found that the SSC-PFSA membrane shows thermal stability by higher crystallinity, and chemical/mechanical stability than the LSC-PFSA membrane at high temperature. These fine properties are found to be the factor for applying Aquivion™ E87-05S membrane rather than Nafion ® 212 membrane for a high temperature fuel cell.
ACS Applied Materials & Interfaces, 2009
Random disulfonated poly(arylene ether sulfone)-silica nanocomposite (FSPAES-SiO 2) membranes were physicochemically tuned via surface fluorination. Surface fluorination for 30 min converted about 20% of the C-H bonds on the membrane surface into C-F bonds showing hydrophobicity and electronegativity at the same time. The membranes with hydrophobic surface properties showed high dimensional stability and low methanol permeability when hydrated for direct methanol fuel cell applications. In particular, the surface enrichment of fluorine atoms led to anisotropic swelling behavior, associated with a stable electrode interface formation. Interestingly, in spite of the use of a random copolymer as a polymer matrix, the low surface free energy of the C-F bonds induced a well-defined continuous ionic channel structure, similar to those of multiblock copolymers. In addition to the morphological transition, fluorine atoms with high electron-withdrawing capability promoted the dissociation of sulfonic acid (-SO 3 H) groups. Consequently, FSPAES-SiO 2 membranes exhibited improved proton conductivity. Thus, FSPAES-SiO 2 membranes exhibited significantly improved single-cell performances (about 200%) at a constant voltage of 0.4 V in comparison with those of Nafion 117 and nonfluorinated membranes. Surprisingly, their good electrochemical performances were maintained with very low nonrecovery loss over the time period of 1400 h and interfacial resistances 380% times lower than those of conventional membrane-electrode assemblies comprising the control hydrocarbon membrane and a Nafion binder for the electrodes.
The Development of New Membranes for Proton Exchange Membrane Fuel Cells
ECS Transactions, 2007
Recent work at 3M has focused on the development of solvent cast proton exchange membranes (PEM's) for use in PEM fuel cells. These new membranes are a perfluorinated sulfonic acids based on a low molecular weight perfluorinated monomer and they exhibit excellent mechanical properties and chemical stability and high ionic conductivity. The low molecular weight of the monomer allows membranes with equivalent weight as low as 800 g/mole to have good mechanical properties when hydrated. Stabilizing additives in these membranes have been shown to improve the oxidative stability in Fenton's tests. Physical property, conductivity and fuel cell tests have been performed. When incorporated into membrane electrode assemblies, these new membranes have provided excellent performance and a greater than 15-fold increase in durability under accelerated fuel cell test conditions, compared with similar commercial PEM's.
Recent advances in proton exchange membranes for fuel cell applications
Chemical Engineering Journal, 2012
h i g h l i g h t s " We summarize recent developments of PEMs that maintain performance at high temperature and low relative humidity. " Three types of PEMs are evaluated: polymeric, ceramic, and inorganic-organic composite. " The advantages and limitations of three types of PEMs under different operation conditions are discussed.
2010
Direct methanol fuel cell (DMFC) system has tremendous potential to be developed as energy converters due to the simplicity and low temperature of its operation. However, the weaknesses of commercial polymer electrolyte membrane of the cell, perfluorinated ionomer (PFI) membrane, such as methanol crossover, limited operating temperature, susceptibility to osmotic swelling and high costs are among the factors hindering the commercialization of DMFC. This paper reviews a number of studies that have been recently performed in order to overcome the weaknesses. This review has classified the membrane development into three different branches, namely the modification of PFI membranes, the development of other fluoropolymer membranes, and the development of non-fluorinated polymers membranes.
Investigation Of Short-Side-Chain Ionomer And Membrane For Proton Exchange Membrane Fuel Cells
Progress in Canadian Mechanical Engineering, 2018
Proton exchange membrane (PEM) fuel cells have been progressively designed to become suitable for hightemperature operation to achieve further performance improvements. However, the current state-of-the-art fuel cell materials, such as long-side-chain (LSC) ionomers and membranes, are not suitable for high-temperature operation, requiring development and investigation of alternative materials. In this study, short-side-chain (SSC) membrane and ionomer are considered as potential materials, and performance of a membrane-electrode assembly (MEA) manufactured with the SSC ionomer and membrane is experimentally investigated in a scaled-up fuel cell (45 cm 2). Comparison is made with an MEA based on the LSC ionomer and membrane under identical preparation and testing conditions. The catalyst layers (CLs) made of either SSC or LSC ionomer are characterized through scanning electron microscopy (SEM) to understand their surface morphology and microstructure. Results show that the SSC ionomer embedded in the CL provides much more uniform surface morphology and well-proportioned microstructural characteristics than its LSC counterpart. Further, the MEA based on SSC ionomer and membrane demonstrates considerable performance superiorities under all the applied operating conditions. Furthermore, the performance of the MEA based on the SSC ionomer and membrane is found to be less sensitive to changes in operating conditions.
Review of the proton exchange membranes for fuel cell applications
International Journal of Hydrogen Energy, 2010
Proton-exchange membrane fuel cells (PEMFCs) are considered to be a promising technology for clean and efficient power generation in the twenty-first century. Proton exchange membranes (PEMs) are the key components in fuel cell system. The researchers have focused to reach the proton exchange membrane with high proton conductivity, low electronic conductivity, low permeability to fuel, low electroosmotic drag coefficient, good chemical/thermal stability, good mechanical properties and low cost. These are classified into the "iron triangle" of performance, durability, and cost. Current PEMFC technology is based on expensive perflourinated proton-exchange membranes (PEMs) that operate effectively only under fully hydrated conditions. There is considerable application-driven interest in lowering the membrane cost and extending the operating window of PEMs. PEMFC system complexity could be reduced by the development of 'water-free' electrolytes that do not require hydration. It also enables the PEMFC to be operated under 'warm' conditions (i.e. above 100 C) thus further improving its efficiency. Capital cost could also be further reduced because at warmer conditions less Pt could be used. This paper presents an overview of the key requirements for the proton exchange membranes (PEM) used in fuel cell applications, along with a description of the membrane materials currently being used and their ability to meet these requirements. A number of possible alternative candidates are reviewed and presented in this paper. Also discussed are some of the new materials, technologies, and research directions being pursued to try to meet the demanding performance and durability needs of the PEM fuel cell industry. The alternative PEMs are classified into three categories: (1) modified Nafion Ò composite membranes; (2) functionalized non-fluorinated membranes and composite membranes therein; and (3) acidebase composite membranes. Several commonly used inorganic additives are reviewed in the context of composite membranes. Finally, the general methods of the measuring and evaluating of proton exchange membrane properties have been investigated such as proton conductivity, ion exchange capacity, water uptake, gas permeability, methanol permeability, durability, thermal stability and fuel cell performance test.
Composites of proton-conducting polymer electrolyte membrane in direct methanol fuel cells
Critical Reviews in Solid State and …, 2007
Fuel cells are a replacement for the conventional energy resources. As early as 1839, William Grove discovered the basic operating principle of fuel cells by reversing water electrolysis to generate electricity from hydrogen and oxygen. A Direct Methanol Fuel Cell (DMFC) operates on liquid fuel, which is one of the exciting varieties of fuel cells. There are many problems with DMFCs such as the high cost of electrolyte membranes, high platinum loading, CO poisoning, fuel cross-over, and so on. In this review, research regarding the solution of these problems will be cited and discussed. The electrical performance (in respect to power density) of the composites for the Nafion R and other perfluorinated membranes in DMFC are evaluated. The effect of these modifications on various aspects, such as mobility of protons through the membrane, permeation of hydronium ions, and cross-over of methanol through the membrane leading to the negative potential, have previously been discussed. Therefore, the main focus of this review is on the effect of composites of Nafion R and non-fluorinated membranes on the DMFC performance.
2011
which is two times longer than that of un-fluorinated SPFEK. The PEM properties and single fuel cell performances were investigated by comparison of un-and fluorinated polymer ionomers. The fluorinated membranes demonstrated an enhanced hydrophobic surface property, increased proton conductivities and better single fuel cell performances. Surface fluorination provides a convenient and useful approach to prepare highly proton conductive membrane with long life-time PEM fuel cell applications.