Proton Exchange Membranes (PEM)
“Fuel cells have been proposed as a power source for electric vehicles and other applications. One known fuel cell is the PEM (i.e., Proton Exchange Membrane) fuel cell that includes a so-called MEA ("membrane-electrode-assembly") comprising a thin, solid polymer membrane-electrolyte having an anode on one face and a cathode on the opposite face. The anode and cathode typically comprise finely divided carbon particles, very finely divided catalytic particles supported on the internal and external surfaces of the carbon particles, and proton conductive material intermingled with the catalytic and carbon particles. The MEA is sandwiched between gas diffusion media layers and a pair of electrically conductive contact elements which serve as current collectors for the anode and cathode, which may contain appropriate channels and openings therein for distributing the fuel cell's gaseous reactants (i.e. H.sub.2 and O.sub.2/air) over the surfaces of the respective anode and cathode.”
“Bipolar PEM fuel cells comprise a plurality of the MEAs stacked together in electrical series while being separated one from the next by an impermeable, electrically conductive contact element known as a bipolar plate or septum. The bipolar plate has two working surfaces, one confronting the anode of one cell and the other confronting the cathode on the next adjacent cell in the stack, and electrically conducts current between the adjacent cells. Contact elements at the ends of the stack contact only the end cells and are referred to as end plates. “
(Dadheech et al of General Motors, US Patent 7,803,476)
Phosphoric Acid Membranes for Fuel Cells
Polyazole Membranes
Polyester Fuel Cell Membranes
Polyether Membranes for Fuel Cells
Polysulfone Proton Exchange Membranes
PVDF Proton Exchange Membranes
Recent US Patents
11/2/2010
7,824,820
Electrolyte film and solid polymer fuel cell using the same
Yamaguchi et al of Nitto Denko Corporation, Japan, have developed an electrolyte membrane having a porous base material having pores filled with a first polymer capable of conducting a proton, wherein the porous base material comprises i) at least one second polymer selected from the group consisting of polyolefins and ii) a third polymer having double bond in the polymer, and contains a crosslinked second polymer wherein molecules of the second polymer are crosslinked with one another; and a fuel cell, particularly a solid polymer fuel cell, more specifically a direct methanol polymer fuel cell, using the electrolyte membrane. The electrolyte membrane is excellent in the inhibition of permeation of methanol, exhibits no or reduced change in its area, and is excellent in proton conductivity. (RDC 3/2/2011)
7,824,819
Membrane-electrode assembly for mixed reactant fuel cell and mixed reactant fuel cell system including the same
Kwak et al of Samsung SDI Co., South Korea have developed a membrane-electrode assembly for a mixed reactant fuel cell system. The membrane-electrode assembly of the present invention instead includes an electrode substrate that is disposed on a surface of an anode or a cathode of the membrane-electrode assembly. The electrode substrate has a flow path, through which a fuel and an oxidant are supplied. The fuel and oxidant are absorbed into the electrode substrate and further into the anode and the cathode. The fuel and the oxidant are selectively oxidized and reduced in the anode and the cathode, respectively, to produce electricity. (RDC 3/2/2011)
10/19/2010
7,816,482
Epoxy-crosslinked sulfonated poly (phenylene) copolymer proton exchange membranes
Hibbs of Sandia, New Mexico developed an epoxy-crosslinked sulfonated poly(phenylene) copolymer composition used as proton exchange membranes, . These improved membranes are tougher, have higher temperature capability, and lower SO.sub.2 crossover rates. (RDC 1/24/2011)
7,816,416
Polymer membrane for fuel cell, method of preparing the same, membrane-electrode assembly including the same, and fuel cell system including the same
Han et al of Samsung, South Korea developed a polymer electrolyte membrane for a fuel cell including a polymer micelle inside a hydrophilic channel. The micelle includes a vinyl-based polymer surrounded by an anionic surfactant. (RDC 1/24/2011)
7,816,053
Membrane-electrode assembly for solid polymer electrolyte fuel cell
Kanaoka, Iguchi and Sohma of Honda, Japan has developed a membrane-electrode assembly with superior hot water resistance. The membrane is an aromatic fluoro polymer. (RDC 1/24/2011)
Cho and Park of Samsung, Japan has developed a proton conductive electrolyte including a polymerized polyurethane, polyethylene(metha)acrylic acid (PEAA), and a cross-linking agent mixture; an electrode and a catalyst layer. The proton conductive electrolyte can be prepared at lower costs than conventionally used polybenzimidazole and NAFION and can be easily formed into a membrane with a controlled thickness by casting. The fuel cell produced using the proton conductive electrolyte and/or the electrode can operate at 100.degree. C. or higher under non-humidified conditions and exhibits an improved performance. (RDC 1/24/2011)
Recent Journal Articles
2/4/2011
Freeze-dried solid foams prepared from carbon nanotube aqueous suspension: Application to gas diffusion layers of a proton exchange membrane fuel cell
(22-30) Chemical Engineering and Processing 50, #1 (2011)
Nakagawa et al, Japan and Thailand prepared freeze-dried macroporous solid foams from multi-walled carbon nanotube (MWCNT) aqueous suspensions dispersed by chitosan. Thin film shaped CNT solid foams were prepared, and applied to the gas diffusion layers (GDLs) of a laboratory scale proton exchange membrane fuel cell (PEMFC). (RDC 2/11/2011)
1/28/2011
Mesoscale modeling of the influence of morphology on the mechanical properties of proton exchange membranes
(201-210) Polymer 52 #1 (2011)
Qi and Lai of General Motors, Michigan used multi-scale modeling to obtain the morphologies of hydrated perfluorosulfonic acid (PFSA) membranes and then to predict their mechanical properties based on the simulated morphology. Spherical and cylindrical morphologies represented cast and extruded membranes. The cylindrical morphology develops much lower peak stress than the isotropic spherical morphology under the same level of strain. These results explain why the extruded membranes show more than 10 times longer life in durability tests than recast membranes, despite having similar bulk moduli. (RDC 1/27/2011)
1/7/2010
A modified poly(aryle ether ketone sulfone) proton exchange membrane with in situ polymerized polypyrrole for the direct methanol fuel cells
(914–920)Journal of Applied Polymer Science 120 #2 (2011)
Wang of Changchun University of Technology, China prepared sulfonated poly(aryle ether ketone sulfone)/ polypyrrole(SPAEKS/Ppy) composite membranes with different contents of polypyrrole were prepared by chemically in situ polymerization. Polypyrrole particles were uniformly distributed throughout the membranes matrix. The composite membranes showed good thermal stability, low water uptake, and high proton conductive capability. The composite membranes showed very good potential in direct methanol fuel cells (DMFCs). (RDC 1/11/2011)
Nafion®—titania nanocomposite proton exchange membranes
(1186–1192)Journal of Applied Polymer Science 120 #2 (2011)
Ye et al of Wuhan University of Technology, China have developed proton exchange membranes consisting of Nafion® and crystallized titania nanoparticles for improved water-retention and proton conductivity at elevated temperature and low relative humidity. (RDC 1/10/2011)
10/29/2010
‘Click’-functionalization of poly(sulfone)s and a study of their utilities as proton conductive membranes in direct methanol fuel cells
(5352-5358) Polymer 51 #23 (2010)
Norris et al of the University of Texas at Austin using the copper-catalyzed 1,3-dipolar “click” cycloaddition reaction, poly(sulfone)s containing pendant azide moieties were functionalized with various quantities of sodium 3-(prop-2-ynyloxy)propane-1-sulfonate and crosslinked with 1,7-octadiyne. The membranes showed a reduction in methanol permeability with increasing concentration of crosslinker and exhibited performance on par with direct methanol fuel cells containing Nafion-based membranes. (RDC 12/17/2010)
Proton conducting membranes based on semi-interpenetrating polymer network of Nafion® and polybenzimidazole
(5473-5481) Polymer 51 #23 (2010)
Guan et al ofTongji University prepared the interpenetrating network during membrane formation using N-vinylimidazole as the crosslinker. The composite membranes exhibit excellent thermal stability, high-dimensional stability, and significantly improved mechanical properties compared with Nafion®212. The benzimidazole structure of PBI and the acidic component of Nafion® provide the possibility for the proton mobility via structure diffusion involving proton transfer between the heterocycles with a corresponding reorganization of the hydrogen bonded network (RDC 12/17/2010)
Novel side-chain-type sulfonated hydroxynaphthalene-based Poly(aryl ether ketone) with H-bonded for proton exchange membranes
(3047-3053) Polymer 51 #14 (2010)
Zhu et al of Jilin University, China synthesized these polymers by post grafted method and the sulfonated degree (Ds) of the polymers could be well controlled. These polymers are candidate materials for fuel cell applications. (RDC 12/22/2010)
Review Articles
2/4/2011
Review
Recent developments in fuel-processing and proton-exchange membranes for fuel cells
(26–41)Polymer International 60 #1 (2011)
Bai and Ho of The Ohio State University , Ohio reviews the development of proton-exchange membrane fuel cells (PEMFCs) for both mobile and stationary applications. This review covers two types of new membranes: (1) carbon dioxide-selective membranes for hydrogen purification and (2) proton-exchange membranes; both of these are crucial to the widespread application of PEMFCs. On hydrogen purification for fuel cells, the new facilitated transport membranes synthesized from incorporating amino groups in polymer networks have shown high CO2 permeability and selectivity versus H2. The membranes can be used in fuel processing to produce high-purity hydrogen (with less than 10 ppm CO and 10 ppb H2S) for fuel cells. On proton-exchange membranes, the new sulfonated polybenzimidazole copolymer-based membranes can outperform Nafion® under various conditions, particularly at high temperatures and low relative humidities.
(RDC 2/3/2011)
1/21/2011
Block Copolymers for Fuel Cells
(1–11) Macromolecules 44 #1 (2011)
Elabd and Hickner of Drexel University and Pennsylvania State University, Pennsylvania review ion-containing block copolymers as next-generation proton exchange membranes in hydrogen and methanol fuel cells. These materials’ self-assembled ordered nanostructures facilitate proton transport over a wide range of conditions, a requirement for robust fuel cell performance. (RDC 1/19/2011)