Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
  • H01M4/88—Processes of manufacture
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0289—Means for holding the electrolyte
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1007—Fuel cells with solid electrolytes with both reactants being gaseous or vaporised
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
  • H01M8/1018—Polymeric electrolyte materials
  • H01M8/1041—Polymer electrolyte composites, mixtures or blends
  • H01M8/1046—Mixtures of at least one polymer and at least one additive
  • H01M8/1048—Ion-conducting additives, e.g. ion-conducting particles, heteropolyacids, metal phosphate or polybenzimidazole with phosphoric acid
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
  • H01M8/1018—Polymeric electrolyte materials
  • H01M8/1041—Polymer electrolyte composites, mixtures or blends
  • H01M8/1046—Mixtures of at least one polymer and at least one additive
  • H01M8/1051—Non-ion-conducting additives, e.g. stabilisers, SiO2 or ZrO2
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
  • H01M8/1018—Polymeric electrolyte materials
  • H01M8/1067—Polymeric electrolyte materials characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
  • H01M8/1018—Polymeric electrolyte materials
  • H01M8/1069—Polymeric electrolyte materials characterised by the manufacturing processes
  • H01M8/1072—Polymeric electrolyte materials characterised by the manufacturing processes by chemical reactions, e.g. insitu polymerisation or insitu crosslinking
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/24—Mechanical properties, e.g. strength
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/40—Fibre reinforced membranes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49108—Electric battery cell making
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49108—Electric battery cell making
  • Y10T29/49115—Electric battery cell making including coating or impregnating

Definitions

• the present invention relates to membrane-electrode assemblies
• Increased power fuel cells comprising at least two electrochemically active electrodes separated by a polymer electrolyte membrane.
• Stability of the polymer in combination with acidic water and the reaction gases hydrogen and oxygen usually limits the operating temperature of the PEM fuel cell stacks to 80.
• Fuel cell can not be realized.
• Object of the present invention was therefore to provide membrane electrode assemblies and fuel cells with the highest possible performance, which can be produced in the simplest possible way, on a large scale, as inexpensively and as reproducibly.
• the fuel cell should preferably have the following properties:
• the fuel cells should last as long as possible.
• the fuel cells should be able to be used at operating temperatures which are as high as possible, in particular above 100 ° C.
• the fuel cells should have as high a quiescent voltage as possible and as little gas penetration as possible (gas cross-over). Furthermore, they should be able to be operated at the lowest possible stoichiometry. • The fuel cells should, if possible, do without additional fuel gas humidification.
• the fuel cells should be able to withstand permanent or changing pressure differences between anode and cathode in the best possible way. • In particular, the fuel cells should be robust against different ones
• the fuel cells should have improved temperature and corrosion resistance and a comparatively low gas permeability, especially at high temperatures.
• the present invention accordingly provides a membrane-electrode assembly comprising at least two electrochemically active electrodes which are separated by at least one polymer-electrolyte membrane and wherein the above-mentioned polymer-electrolyte membrane comprises reinforcing elements which support the polymer electrolyte.
• Penetrate membrane at least partially.
• polymer electrolyte membranes are known per se and are not subject to any restriction. Rather, all proton-conductive materials are suitable.
• membranes are used which comprise acids, which acids may be covalently bound to polymers.
• a sheet material may be doped with an acid to form a suitable membrane.
• gels in particular polymer gels, can also be used as the membrane, particularly suitable for the present purposes
• Polymer membranes are described for example in DE 102 46461.
• These membranes may be inter alia by swelling flat materials, for example a polymeric film, with a liquid comprising acidic compounds, or by preparing a mixture of polymers and acidic compounds and then forming a membrane by forming a sheet article and then solidifying it Membrane to be generated.
• Suitable polymers include polyolefins, such as
• high temperature stable polymers which contain at least one nitrogen, oxygen and / or sulfur atom in one or in different repeat units.
• Blends preferred which contain polyazoles and / or polysulfones.
• the preferred blend components are polyether sulfone, polyether ketone and polymers modified with sulfonic acid groups, as described in German patent application DE 100 522 42 and DE 102 464 61.
• polymer blends which comprise at least one basic polymer and at least one acidic polymer, preferably in a weight ratio of from 1:99 to 99: 1 (so-called acid-base polymer blends), have proven especially useful for the purposes of the present invention.
• acidic polymers in this context include polymers having sulfonic acid and / or phosphonic acid groups.
• Very particularly suitable acid-base polymer blends according to the invention are described in detail, for example, in the publication EP1073690 A1.
• a particularly preferred group of basic polymers are polyazoles.
• a basic polymer based on polyazole contains recurring azole units of the general formula (I) and / or (II) and / or (III) and / or (IV) and / or (V) and / or (VI) and / or ( VII) and / or (VIII) and / or (IX) and / or (X) and / or (XI) and / or (XII) and / or (XIII) and / or (XIV) and / or (XV) and / or (XVI) and / or (XVII) and / or (XVIII) and / or (XIX) and / or (XX) and / or (XXI) and / or (XXII) and / or (XXII) and / or (XXII)) and / or (XXII)) and / or (XXII)) and / or (XXII)) and / or (XX
• Ar 8 are the same or different and represent a trivalent aromatic or heteroaromatic group which may be mononuclear or polynuclear,
• Ar 9 are the same or different and represent a di- or tri- or tetravalent aromatic or heteroaromatic group which may be mononuclear or polynuclear,
• Ar 10 are the same or different and represent a divalent or trivalent aromatic or heteroaromatic group which may be mononuclear or polynuclear,
• Ar 11 are the same or different and are a divalent aromatic or heteroaromatic group which may be mononuclear or polynuclear, X is the same or different and is oxygen, sulfur or a
• Amino group which represents a hydrogen atom, a 1-20 carbon atoms group, preferably a branched or unbranched
• Alkyl or alkoxy group, or an aryl group as another radical R is identical or different hydrogen, an alkyl group or an aromatic group and in formula (XX) is an alkylene group or an aromatic group, with the proviso that R in formula (XX ) is not hydrogen, and n, m is an integer greater than or equal to 10, preferably greater than or equal to 100.
• Preferred aromatic or heteroaromatic groups are derived from benzene, naphthalene, biphenyl, diphenyl ether, diphenylmethane, diphenyldimethylmethane, bisphenone, diphenylsulfone, quinoline, pyridine, bipyridine, pyridazine, pyrimidine, pyrazine,
• the substitution pattern of Ar 1 , Ar 4 , Ar 6 , Ar 7 , Ar 8 , Ar 9 , Ar 10 , Ar 11 is arbitrary, in the case of phenylene, for example, Ar 1 , Ar 4 , Ar 6 , Ar 7 , Ar 8 , Ar 9 , Ar 10 , Ar 11 are ortho, meta and para-phenylene. Particularly preferred groups are derived from
• alkyl groups are short chain alkyl groups of 1 to 4 carbon atoms, such as. For example, methyl, ethyl, n- or i-propyl and t-butyl groups.
• Preferred aromatic groups are phenyl or naphthyl groups.
• the alkyl groups and the aromatic groups may be substituted.
• Preferred substituents are halogen atoms such as. For example, fluorine, amino groups, hydroxy groups or short-chain alkyl groups, such as. For example, methyl or ethyl groups.
• the polyazoles can also have different recurring units which differ, for example, in their radical X. Preferably, however, it has only the same X radicals in a repeating unit.
• polyazole polymers are polyimidazoles, polybenzothiazoles, polybenzoxazoles, polyoxadiazoles, polyquinoxalines, polythiadiazoles, poly (pyridines), poly (pyrimidines) and poly (tetrazapyrenes).
• the polymer containing recurring azole units is a copolymer or a blend containing at least two units of the formulas (I) to (XXII) which differ from each other.
• the polymers can be present as block copolymers (diblock, triblock), random copolymers, periodic copolymers and / or alternating polymers.
• the polymer containing recurring azole units is a polyazole which contains only units of the formula (I) and / or (II).
• the number of repeating azole units in the polymer is preferably an integer greater than or equal to 10.
• Particularly preferred polymers contain at least 100 recurring azole units.
• polymers containing recurring benzimidazole units are preferred.
• Some examples of the most useful polymers containing benzimidazole recurring units are represented by the following formulas:
• n and m are integers greater than or equal to 10, preferably greater than or equal to 100.
• the polyazoles used, but especially the polybenzimidazoles are characterized by a high molecular weight. Measured as intrinsic viscosity, this is at least 0.2 dl / g, preferably 0.8 to 10 dl / g, in particular 1 to 10 dl / g.
• Preferred polybenzimidazoles are commercially available under the trade name Celazole®.
• Preferred polymers include polysulfones, especially polysulfone having aromatic and / or heteroaromatic groups in the backbone. According to a particular aspect of the present invention, preferred
• Polysulfones and polyethersulfones a melt volume rate MVR 300/21, 6 is less than or equal to 40 cm 3/10 min, especially less than or equal to 30 cm 3/10 min and particularly preferably less than or equal to 20 cm 3/10 min measured according to ISO 1133.
• polysulfones having a Vicat softening temperature VST / A / 50 of 18O 0 C to 230 0 C are preferred.
• the polysulfones described above may under the trade names ® Victrex 200 P 1 ® Victrex 720 P, ® Ultrason E, ® Ultrason S, ® Mindel, ® Radel A 1 ® Radel R, ® Victrex HTA, ® Astrel and ® Udel be obtained commercially.
• polyether ketones polyether ketone ketones
• polyether ether ketones polyether ketone ketones
• polyaryl ketones are particularly preferred. These high performance polymers are known per se and can be obtained commercially under the trade names Victrex® PEEK TM, ® Hostatec, ® Kadel.
• a polymer preferably a polyazole
• polar, aprotic solvents such as, for example, dimethylacetamide (DMAc)
• DMAc dimethylacetamide
• the reinforcing elements are preferably introduced into the film during film production.
• the film thus obtained can be treated with a washing liquid as described in German patent application DE 101 098 29.
• the cleaning of the polyazole film from solvent residues described in the German patent application surprisingly improves the mechanical properties of the film. These properties include in particular the modulus of elasticity, the tear strength and the fracture toughness of the film.
• the polymer film may have further modifications, for example by crosslinking, as described in German patent application DE 101 107 52 or in WO 00/44816.
• the polymer film used contains a basic polymer and at least one Embedded membrane and protrude, if at all, only sporadically out of her.
• the membranes reinforced according to the invention can no longer be delaminated without destruction
• Electrolyte membrane and the reinforcing elements each form separate layers, which are indeed connected to each other, but do not penetrate each other.
• the present invention includes only those reinforced polymer electrolyte membranes in which the reinforcing elements are at least partially connected to the membrane.
• a composite of reinforcing element and membrane is considered in which the reinforcing elements expediently absorb a force such that in the force-elongation diagram at 20 ° C. the reference force of the polymer electrolyte membrane with reinforcing elements, compared with the polymer Electrolyte membrane without
• Reinforcing elements in the range between 0 and 1% elongation at least one location by at least 10%, preferably by at least 20% and most preferably by at least 30%, different.
• the polymer electrolyte membrane is preferably fiber-reinforced and the reinforcing elements preferably comprise monofilaments, multifilaments, long and / or short fibers, hybrid yarns and / or bi-component fibers.
• the reinforcing element can also form a textile surface. Suitable textile surfaces are nonwovens, woven fabrics, knitted fabrics, knitted fabrics, felts, scrims and / or meshes, particularly preferably scrims,
• Nonlimiting examples of the above-mentioned fabrics are those of poly (acrylic), poly (ethylene terephthalate), poly (propylene), poly (tetrafluoroethylene), poly (ethylene-co-tetrafluoroethylene) (ETFE), 1: 1 alternating copolymer of ethylene and chlorotrifluoroethylene (E-CTFE), polyvinylidene fluoride (PVDF), poly (acrylonitrile) and polyphenylene sulfide (PPS).
• Fabrics designate products of predominantly crossed threads of monofilaments and / or multifilament threads.
• the mesh size of the textile surface may usually be 20 to 2000 microns, for the purposes of the present invention, textile surfaces, in particular tissue, scrim and grid, have proven particularly useful with a mesh size in the range of 30 to 300 microns.
• the mesh size can be determined, for example, by electronic image analysis of an optical or TEM image.
• the open screen surface a 0 of the textile surface, in particular of the fabric, scrim and grid, can usually be in the range from 0.1 to 98%, preferably in the range from 20 to 80%. She can talk about the relationship Adhesively consolidated nonwovens are preferably obtained by bonding the fibers with liquid binders, in particular with acrylate polymers, SBR / NBR, polyvinyl ester or polyurethane dispersions, or by melting or dissolving so-called binder fibers which have been added to the nonwoven during production.
• the fiber surfaces are conveniently dissolved by suitable chemicals and pressure bonded or heat sealed at elevated temperature.
• the nonwoven fabrics are further reinforced by additional threads, woven or knitted fabric.
• the weight per unit area of the nonwoven fabrics is advantageously 30 g / m 2 to 500 g / m 2 , in particular 30 g / m 2 to 150 g / m 2 .
• Nonlimiting examples of particularly preferred nonwovens are SEFAR PETEX ⁇ , SEFAR FLUORTEX ⁇ , SEFRA PEEKTEX ⁇ .
• the composition of the reinforcing elements can in principle be chosen freely and adapted to the specific application.
• the reinforcing elements expediently contain glass fibers, mineral fibers, natural fibers, carbon fibers, boron fibers, synthetic fibers, polymer fibers and / or ceramic fibers, in particular SEFAR CARBOTEX®, SEFAR PETEX®, SEFAR FLUORTEX®,
• the reinforcing elements which may be part of a woven, knitted, knitted or nonwoven fabric, may have a virtually round cross-section or may have other shapes, such as dumbbell, kidney-shaped, triangular or multilobal cross-sections. Also bicomponent fibers are possible.
• the reinforcing elements preferably have a maximum diameter in the range of 10 ⁇ m to 500 ⁇ m, preferably in the range of 20 ⁇ m to 300 ⁇ m, 22
• the proton-conductive membranes are preferably obtained by a process comprising the steps
• step II heating the solution obtainable according to step I) under inert gas to 5 temperatures of up to 400 0 C,
• step IV forming a membrane using the solution of the polymer according to step II), optionally after intermediate cooling, on the support of step III) in such a way that the reinforcing elements at least the solution
• step 30 C) applying a layer using the mixture according to step A) on the carrier from step B) in such a way that the reinforcing elements at least partially penetrate the mixture
• step D) heating of the sheet / layer obtainable according to step C) under inert gas to temperatures of up to 350 0 C, preferably up to 280 0 C below
• step E) Treatment of the membrane formed in step D) (until it is self-supporting).
• step D) (heating 23
• step C) can take place.
• step B it is also possible to omit step B) and to perform the feeding of the 5 reinforcing elements before or during step D).
• aromatic or heteroaromatic carboxylic acid compounds to be used in step A) preferably comprise di-carboxylic acids and tricarboxylic acids and tetracarboxylic acids or their esters or their anhydrides or their acid chlorides.
• aromatic carboxylic acids equally includes heteroaromatic carboxylic acids.
• the aromatic dicarboxylic acids are isophthalic acid, terephthalic acid, phthalic acid, 5-hydroxyisophthalic acid,
• Dimethylaminoisophthalic acid 5-N, N-diethylaminoisophthalic acid, 2,5-dihydroxyterephthalic acid, 2,6-dihydroxyisophthalic acid, 4,6-dihydroxyisophthalic acid, 2,3-dihydroxyphthalic acid, 2,4-dihydroxyphthalic acid, 3,4-dihydroxyphthalic acid, 3-fluorophthalic acid, 5-fluoroisophthalic acid, 2-
• Tetrafluoroterephthalic acid 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, 1,8-dihydroxynaphthalene-3,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, benzophenone 4,4'-dicarboxylic acid, diphenylsulfone
• C5-C12-aryl-esters or their acid anhydrides or their acid chlorides are preferably 1,3,5-benzenetricarboxylic acid (trimesic acid), 1,4-benzene-tricarboxylic acid.
• tricarboxylic acid trimellitic acid
• (2-carboxyphenyl) iminodiacetic acid 3,5,3'-biphenyl tricarboxylic acid or 3,5,4'-biphenyl tricarboxylic acid.
• aromatic tetracarboxylic acids or their C 1 -C 20 -alkyl esters or C 5 -C 12 -aryl esters or their acid anhydrides or their acid chlorides are preferably 3,5,3 ', 5'-biphenyltetracarboxylic acid, 1, 2, 4,5-benzenetetracarboxylic acid, benzophenonetetracarboxylic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2, 2', 3,3'-biphenyltetracarboxylic acid, 1, 2,5,6-naphthalenetetracarboxylic acid or 1, 4,5,8- naphthalene.
• heteroaromatic carboxylic acids used are preferably heteroaromatic dicarboxylic acids or tricarboxylic acids or tetracarboxylic acids or their esters or their anhydrides.
• Heteroaromatic carboxylic acids are aromatic systems which have at least one
• pyridine-2,5-dicarboxylic acid pyridine-3,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3,5 Pyrazole dicarboxylic acid, 2,6-pyrimidinedicarboxylic acid, 2,5-pyrazinedicarboxylic acid, 2,4,6-pyridinetricarboxylic acid or benzimidazole-5,6-
• Acid anhydrides or their acid chlorides are Acid anhydrides or their acid chlorides.
• the content of tricarboxylic acid or tetracarboxylic acids is between 0 and 30 mol%, preferably 0.1 and 20 mol%, 25 in particular 0.5 and 10 mol%.
• aromatic and heteroaromatic diaminocarboxylic acids used are preferably diaminobenzoic acid or its mono- and dihydrochloride derivatives.
• 35 heteroaromatic carboxylic acids is between 1:99 and 99: 1, preferably
• mixtures are, in particular, mixtures of N-heteroaromatic dicarboxylic acids and aromatic dicarboxylic acids.
• Dihydroxyphthalic acid 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, 1,8-dihydroxynaphthalene-3,6-dicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, benzophenone 4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 4-trifluoromethylphthalic acid, pyridine-2,5-dicarboxylic acid, pyridine-3,5-dicarboxylic acid, pyridine-2 , 6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3,5-pyrazoldicarboxylic acid, 2,6-pyr
• the tetra-amino compounds to be used in step A) preferably comprise
• the polyphosphoric acid used in step A) are commercially available polyphosphoric acids, as are obtainable, for example, from Riedel-de Haen.
• the polyphosphoric acids H n - P n O 3n + I (n> 1) usually have a content calculated as P 2 O 5 (acidimetric) of at least 83%. Instead of a
• Solution of the monomers can also be produced a dispersion / suspension.
• the mixture produced in step A) has a weight ratio of polyphosphoric acid to sum of all monomers of 1: 10,000 to 10,000: 1, preferably 1: 1000 to 25: 1000: 1, in particular 1: 100 to 100: 1, on.
• the layer formation according to step C) takes place by means of measures known per se (casting, spraying, doctoring) which are known from the prior art for polymer film production.
• the carrier all under the conditions as innert to 30 designating carrier are suitable.
• the solution may optionally be treated with phosphoric acid (concentrated phosphoric acid, 85%). This allows the viscosity to be adjusted to the desired value and the formation of the membrane can be facilitated.
• the layer produced according to step C) has a thickness between 20 and 4000 ⁇ m, preferably between 30 and 3500 ⁇ m, in particular between 50 and 3000 ⁇ m.
• step A) also contains tricarboxylic acids or tetracarboxylic acid, this results in a branching / crosslinking of the polymer formed. This contributes to the improvement of the mechanical
• step D Treating the polymer layer produced according to step D) in the presence of moisture at temperatures and for a time sufficient for the layer to have sufficient strength for use in fuel cells.
• the treatment can be carried out so far that the membrane is self-supporting, so that it can be detached from the carrier without damage.
• step D) the flat structure obtained in step C) is heated to a temperature of up to 350 0 C, preferably up to 280 0 C and particularly preferably in the range of 200 0 C to 25O 0 C.
• the inert gases 10 to be used in step D) are known in the art. These include in particular nitrogen as well
• Noble gases such as neon, argon, helium.
• step A) by heating the mixture from step A) to temperatures of up to 350 ° C., preferably up to 280 ° C., the formation of oligomers and / or polymers can already be effected. Depending on the selected temperature and duration, then the heating in step D) can be omitted partially or completely.
• This variant is also the subject of the present invention.
• the treatment of the membrane in step E) is carried out at temperatures above 0 0 C and below 15O 0 C, preferably at temperatures between 10 0 C and 120 0 C, in particular between room temperature (20 0 C) and 90 0 C, in the presence of Moisture or water and / or water vapor and / or water-containing phosphoric acid of up to 85%.
• the treatment is preferably carried out under
• the partial hydrolysis of the polyphosphoric acid in step E) leads to solidification of the membrane and to a decrease in the layer thickness and formation of a membrane having a thickness between 15 and 3000 .mu.m, preferably between 20 and 2000 .mu.m, in particular between 20 and 1500 .mu.m, the self-supporting is.
• the upper temperature limit of the treatment according to step E) is usually 150 ° C. In the case of extremely short exposure to moisture, for example from 27
• this steam can also be hotter than 150 0 C.
• Essential for the upper temperature limit is the duration of the treatment.
• the partial hydrolysis (step E) can also be carried out in climatic chambers, in which the hydrolysis can be controlled in a controlled manner under defined action of moisture.
• the moisture can be adjusted in a targeted manner by the temperature or saturation of the contacting environment, for example gases, such as air, nitrogen, carbon dioxide or other suitable gases, or water vapor.
• gases such as air, nitrogen, carbon dioxide or other suitable gases, or water vapor.
• the duration of treatment depends on the parameters selected above. 10
• the duration of treatment depends on the thickness of the membrane.
• the duration of treatment is between a few seconds to minutes, for example under the action of superheated steam, or up to 15 to full days, for example in the air at room temperature and low relative humidity.
• the treatment time is preferably between 10 seconds and 300 hours, in particular 1 minute to 200 hours.
• the treatment duration is between 1 and 200 hours.
• the membrane obtained according to step E) can be made self-supporting, i. it can be detached from the carrier without damage and then 25 optionally further processed directly.
• the concentration of phosphoric acid and thus the conductivity of the polymer membrane is adjustable.
• a concentration (mol of phosphoric acid based on a repeat unit of the formula (I), for example polybenzimidazole) is between 10 and 50, in particular between
• step 6) treatment of the membrane formed in step 5) until it is self-supporting.
• Reinforcing elements are for example available under the trade name Celtec ®.
• step C) applying a layer using the mixture according to step A) on the carrier from step B) in such a way that the reinforcing elements at least partially penetrate the mixture
• doped polyazole films are obtained by a process comprising the steps
• step B) heating the solution from step A) under inert gas to temperatures of up to 400 0 C, preferably up to 350 0 C, in particular of up to 300 0 C,
• step E) Treatment of the membrane formed in step D) until it is self-supporting.
• organic phosphonic anhydrides used in step A) are cyclic compounds of the formula
• anhydrides of the multiple organic phosphonic acids such as the formula of anhydrides of diphosphonic acid 30
• radical R and R ' are identical or different and represent a C 1 -C 20 -carbon-containing group. 5
• C 20 carbon-containing group is preferably the radicals -C 2 -alkyl, particularly preferably methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, - in the context of the present invention, a C t-butyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-octyl or cyclooctyl, C 1 -C 20 -alkenyl,
• aryl particularly preferably phenyl, biphenyl, naphthyl, anthracenyl, triphenylenyl,
• C 20 -Aryloxyaryl particularly preferably p-phenoxyphenyl, Cs-C ⁇ heteroaryl, particularly preferably 2-pyhdyl, 3-pyridyl, 4-pyridyl, quinolinyl, isoquinolinyl, acridinyl, benzoquinolinyl or benzoisoquinolinyl, C 4 -C 2 o-heterocycloalkyl , furyl, benzofuryl, 2-pyrolidinyl, 2-indolyl, 3-indolyl, 2,3-Aryloxyaryl, particularly preferably p-phenoxyphenyl, Cs-C ⁇ heteroaryl, particularly preferably 2-pyhdyl, 3-pyridyl, 4-pyridyl, quinolinyl, isoquinolinyl, acridinyl, benzoquinolinyl or benzoisoquinolinyl, C 4 -C 2 o-heterocycloal
• 35 can form a cyclic system.
• Ci - groups by -O-, -S-, -NR 1 - - or -CONR 2 - C 2 o-carbon containing groups one or more non-adjacent CH 2 may be replaced and one or more H Atoms can be replaced by F.
• one or more non-adjacent CH groups may be replaced by -O-, -S-, -NR 1 - or -CONR 2 and one or more several H atoms can be replaced by F.
• radicals R 1 and R 2 are identical or different at each occurrence H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C-atoms.
• organic phosphonic anhydrides which are partially or perfluorinated.
• the organic phosphonic anhydrides used in step A) can also be used in combination with polyphosphoric acid and / or with P 2 O 5 .
• the polyphosphoric acid is commercially available polyphosphoric acids such as those available from Riedel-de Haen, for example.
• the polyphosphoric acids are commercially available polyphosphoric acids such as those available from Riedel-de Haen, for example.
• organic phosphonic anhydrides used in step A) can also be used in combination with simple and / or multiple organic phosphonic acids.
• the simple and / or multiple organic phosphonic acids are compounds of the formula
• radical R is the same or different and is a C 1 - C 2 o- carbon-containing group and n> 2. Particularly preferred radicals R have already been described above. 35
• the organic phosphonic acids used in step A) are commercially available, for example the products of the company Clariant or Aldrich.
• the organic phosphonic acids used in step A) do not comprise any vinyl-containing phosphonic acids as described in German Patent Application No. 10213540.1. 5
• the mixture produced in step A) has a weight ratio of organic phosphonic anhydrides to the sum of all polymers of 1: 10,000 to 10,000: 1, preferably 1: 1000 to 1,000: 1, in particular 1: 100 to 100: 1. Inasmuch as these phosphonic anhydrides in admixture with polyphosphoric acid or simple and
• organic phosphonic acids 10 or more organic phosphonic acids are used, these are to be considered in the phosphonic anhydrides.
• organophosphonic acids preferably perfluorinated organic phosphonic acids
• the membrane in particular the membrane based on polyazoles, can be crosslinked by the action of heat in the presence of atmospheric oxygen on the surface. This hardening of the membrane surface additionally improves the properties of the membrane.
• the membrane on a the membrane on a
• the oxygen concentration in this process step is usually in the range of 5 to 50% by volume, preferably 10 to 40% by volume, without this being intended to limit it.
• IR infra red, ie light with a wavelength of more than 700 nm
• NIR near IR, ie light with a wavelength in the range of about 700 to 2000 nm or an energy in the range of about 0.6 to 1.75 eV).
• Another method is the irradiation
• the radiation dose is between 5 and 200 kGy.
• the duration of the crosslinking reaction can be in a wide range. In general, this reaction time is in the range of 1 second to 10 hours, preferably 1 minute to 1 hour, without this being a limitation. 33
• the preparation of the reinforced polymer electrolyte membranes can be carried out in a manner known per se. Particularly preferred is the introduction of the reinforcing elements into a flowable or at least still ductile polymer composition and / or monomer or oligomer composition, preferably a polymer melt, solution, dispersion or suspension, and the subsequent solidification of the polymer composition, for example by cooling or removal of volatiles (solvents) and / or chemical reaction (eg, crosslinking or polymerization).
• a flowable or at least still ductile polymer composition and / or monomer or oligomer composition preferably a polymer melt, solution, dispersion or suspension
• the subsequent solidification of the polymer composition for example by cooling or removal of volatiles (solvents) and / or chemical reaction (eg, crosslinking or polymerization).
• the membrane-electrode assembly comprises at least two electrochemically active electrodes (anode and cathode) which are separated by the polymer-electrolyte membrane.
• electrochemically active indicates that the electrodes are capable of catalyzing the oxidation of hydrogen and / or at least one reformate and the reduction of oxygen
• Electrode means that the material is electrically conductive, and the electrode may optionally comprise a noble metal layer Such electrodes are known and are described, for example, in US 4,191,618, US 4,212,714 and US 4,333,805.
• the electrodes preferably include gas diffusion layers in contact with a catalyst layer.
• gas diffusion layers usually planar, electrically conductive and 25 acid-resistant structures are used. These include, for example, graphite fiber
• Papers, carbon fiber papers, graphite cloth and / or papers rendered conductive by the addition of carbon black Through these layers, a fine distribution of the gas and / or liquid streams is achieved.
• gas diffusion layers can be used which contain a mechanically stable support material, which is coated with at least one electrically conductive material, for.
• a mechanically stable support material which is coated with at least one electrically conductive material, for.
• carbon for example carbon black
• particularly suitable support materials include fibers, for example in the form of nonwovens, papers or fabrics, in particular carbon fibers, glass fibers
• Polyester polyethylene terephthalate
• polyphenylene sulfide polyphenylene sulfide
• polyether ketones Further details of such diffusion layers can be found, for example, in WO 9720358.
• the gas diffusion layers preferably have a thickness in the range from 80 ⁇ m to 2000 ⁇ m, in particular in the range from 100 ⁇ m to 1000 ⁇ m and particularly preferably in the range from 150 ⁇ m to 500 ⁇ m. Furthermore, the gas diffusion layers favorably have a high porosity. This is preferably in the range of 20% to 80%.
• the gas diffusion layers may contain conventional additives. These include, but are not limited to, fluoropolymers, e.g. Polytetrafluoroethylene (PTFE) and surface-active substances.
• fluoropolymers e.g. Polytetrafluoroethylene (PTFE)
• surface-active substances e.g. fluoropolymers, e.g. Polytetrafluoroethylene (PTFE) and surface-active substances.
• At least one of the 10 gas diffusion layers may consist of a compressible material.
• a compressible material is characterized by the property that the gas diffusion layer can be pressed without loss of its integrity by pressure on half, in particular to one third of its original thickness. 15
• This property generally includes gas diffusion layers of graphite fabric and / or paper rendered conductive by the addition of carbon black.
• the catalytically active layer contains a catalytically active substance.
• catalytically active substance include precious metals, in particular platinum, palladium, rhodium, iridium and / or ruthenium.
• precious metals in particular platinum, palladium, rhodium, iridium and / or ruthenium.
• These substances can also be used in the form of alloys with one another.
• these substances can also be used in alloys with base metals, such as, for example, Cr, Zr, Ni,
• the abovementioned noble metals and / or base metals are used.
• the above-mentioned metals are used by known methods on a carrier material, usually carbon with a high specific surface, in the form of nanoparticles.
• the catalytically active compounds i. H. the catalysts, used in the form of particles, which preferably have a size in the range of 1 to 1000 nm, in particular 5 to 200 nm and preferably 10 to 100 nm.
• the weight ratio of fluoropolymer to catalyst material comprising at least one noble metal and optionally one or more support materials is greater than 0.05, said ratio preferably being in the range of 0.1 to 0.6.
• This value represents an average value that can be determined by measuring the layer thickness in the cross-section of images that can be obtained with a scanning electron microscope (SEM). 5
• the noble metal content of the catalyst layer is 0.1 to 10.0 mg / cm 2 , preferably 0.2 to 6.0 mg / cm 2 and more preferably 0.2 to 3.0 mg / cm 2 , These values can be determined by elemental analysis of a flat sample.
• the catalyst layer is generally not self-supporting but is usually applied to the gas diffusion layer and / or the membrane. In this case, a part of the catalyst layer can diffuse, for example, into the gas diffusion layer and / or the membrane, whereby
• the surfaces of the polymer electrolyte membrane are in contact with the electrodes such that the first electrode contacts the front side of the polymer electrolyte membrane.
• Membrane partially or completely, preferably only partially, covered.
• the front and the back of the polymer electrolyte membrane denote the side facing away from the viewer or the polymer electrolyte membrane, wherein a viewing from the first electrode (front),
• the cathode in the direction of the second electrode (back), preferably the anode takes place.
• the separator plates if appropriate in conjunction with other sealing materials, seal the gas spaces of the cathode and the anode to the outside and between the gas spaces of the cathode and the anode 15.
• the separator plates are preferably applied sealingly to the membrane-electrode assembly. The sealing effect can be further increased by pressing the composite of Separatorplatten and membrane electrode unit.
• the separator plates preferably each have at least one gas channel for
• Reaction gases which are conveniently arranged on the sides facing the electrodes.
• the gas channels are to allow the distribution of reactant fluids.
• Electrode units are characterized by a significantly improved mechanical stability and strength and therefore can be used for the production of fuel cell stacks with very high performance.
• the usual performance fluctuations of the resulting fuel cell stacks are not
• the membrane-electrode assemblies according to the invention can be used with fluctuating ambient temperatures and atmospheric humidity
• the membrane-electrode units are perfectly suited for installation in fuel cell stacks.
• the membrane-electrode assembly then no longer needs to be conditioned on-site for external installation, which results in manufacturing
• An advantage of preferred membrane-electrode assemblies is that they allow the operation of the fuel cell at temperatures above 120 0 C. This applies to gaseous and liquid fuels, such as hydrogen-containing gases, which are prepared for example in an upstream reforming step of hydrocarbons. 5 For example, oxygen or air can be used as the oxidant.
• membrane-electrode assemblies have a high tolerance to carbon monoxide in operation above 120 0 C even with pure platinum catalysts, ie without a further 10 alloy constituent. At temperatures of 160 ° C., for example, more than 1% of CO can be contained in the fuel gas, without this leading to a noticeable reduction in the power of the fuel cell.
• Preferred membrane-electrode units can be operated in fuel cells without the need to humidify the fuel gases and the oxidants despite the possible high operating temperatures.
• the fuel cell is still stable and the membrane does not lose its conductivity. This simplifies the entire fuel cell system and brings additional cost savings, as the
• preferred membrane-electrode assemblies allow the fuel cell to be cooled to room temperature and below without any problem
• the preferred membrane-electrode assemblies of the present invention exhibit very high long-term stability. It has been found that a fuel cell according to the invention over long periods, for example more than 5000 hours, at temperatures of more than 120 0 C with dry reaction gases
• Performance degradation is detected.
• the achievable power densities are very high even after such a long time.
• the fuel cells according to the invention show a high rest voltage, which after this
• Time is preferably at least 900 mV.
• Fuel cell after this time preferably a low gas passage (gas cross-over).
• the anode side of the fuel cell is operated with hydrogen (5 Uh), the cathode with nitrogen (5 L / h).
• the anode serves as a reference and counter electrode.
• the cathode as a working electrode.
• the resulting current is a measure of the hydrogen permeation rate.
• the current is ⁇ 3 mA / cm 2 , preferably ⁇ 2 mA / cm 2 , more preferably ⁇ 1 mA / cm 2 in a 50 cm 2 cell.
• the measured values of the H 2 cross over apply for a temperature of 160 0 C.
• membrane-electrode assemblies according to the invention are distinguished by improved temperature and corrosion resistance and a comparatively low gas permeability, in particular at high temperatures. A decrease in mechanical stability and structural
• Integrity especially at high temperatures, is optimally avoided according to the invention.
• membrane-electrode assemblies according to the invention can be produced inexpensively and easily.
• the anode catalyst is Pt supported on carbon.
• Cathode The cathode catalyst is a Pt alloy supported on carbon.
• Membrane A The membrane is a phosphoric acid-doped polymer membrane whose polymer consists of para-polybenzimidazole.
• Membrane Electrode Assembly B 5 Anode: The anode catalyst is Pt supported on carbon.
• Cathode The cathode catalyst is a Pt alloy supported on carbon.
• Membrane A The membrane is a phosphoric acid-doped polymer membrane whose polymer consists of para-polybenzimidazole. The membrane was applied on both sides to a polyether ether ketone nonwoven (Sefar Peektex® 50 .mu.m thick.
• the two membrane electrode assemblies were continuously operated in fuel cells having an active area of 50 cm 2 at 200 0 C for 350h (anode gas: hydrogen at 1.2 stoichiometry; cathode gas with air stoichiometry 2) and
• Voltage characteristics are a measure of the performance of the fuel cell. During operation, the cell resistance (I kHz impedance measurement) was measured. The change in cell resistance is a measure of the change in the electrical contact between the membrane-electrode unit and the flow field used.
• Figure 1 shows the current-voltage characteristics after 350h at 200 0 C.
• Table 1 shows the change in cell resistance during the operation of
• Table 2 shows the change in cell resistance during operation of membrane electrode bone B.
• the current-voltage characteristic after 350 h of membrane electrode assembly A is significantly below the characteristic of membrane electrode assembly B.
• the characteristic of membrane electrode assembly B For example, at a current of 0.5A / cm 2, only the cell voltage of membrane electrode assembly A is 26mV below the cell voltage of membrane-electrode unit B.

Landscapes

• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Energy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Composite Materials (AREA)
• Fuel Cell (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
• Conductive Materials (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Reinforced Plastic Materials (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38884848

Family Applications (1)

Country Status (9)

Families Citing this family (27)

Family Cites Families (26)

• 2006
  • 2006-08-02 DE DE102006036019A patent/DE102006036019A1/de not_active Withdrawn
• 2007
  • 2007-07-31 WO PCT/EP2007/006741 patent/WO2008014964A2/de active Application Filing
  • 2007-07-31 CN CN2007800288407A patent/CN101523642B/zh not_active Expired - Fee Related
  • 2007-07-31 JP JP2009522159A patent/JP5698907B2/ja not_active Expired - Fee Related
  • 2007-07-31 CA CA002659475A patent/CA2659475A1/en not_active Abandoned
  • 2007-07-31 RU RU2009106949/07A patent/RU2411616C2/ru not_active IP Right Cessation
  • 2007-07-31 EP EP07786440A patent/EP2059964A2/de not_active Withdrawn
  • 2007-07-31 KR KR1020097000527A patent/KR101479354B1/ko not_active IP Right Cessation
  • 2007-07-31 KR KR1020147027038A patent/KR20140133884A/ko not_active Application Discontinuation
  • 2007-07-31 US US12/375,550 patent/US20090258274A1/en not_active Abandoned
• 2013
  • 2013-03-05 JP JP2013042592A patent/JP5793524B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events