DE10115928A1 - Electrolyte membrane, this comprehensive membrane electrode assembly, manufacturing method and special uses - Google Patents

Abstract

The invention relates to a proton-conductive, flexible electrolyte membrane for a fuel cell, which is impermeable to the reaction components of the fuel-cell reaction. Said membrane comprises a composite material that is permeable to substances and that consists of a flexible, perforated support comprising a glass, in addition to a porous ceramic material. The composite material is interspersed with a proton-conductive material, which is suitable for selectively conducting protons through the membrane.

Description

The present invention relates to special proton-conductive, flexible Electrolyte membranes for a fuel cell, process for producing the same Electrolyte membranes and a flexible membrane electrode unit for one Fuel cell which comprises an electrolyte membrane according to the invention. The The present invention further relates to special intermediates in the manufacture membrane electrode assembly and special uses of the electrolyte membrane and membrane electrode assembly.

Fuel cells contain electrolyte membranes Ensure proton exchange between the half-cell reactions and on the other hand, prevent a short circuit between the Half-cell reactions are coming.

Conventionally, so-called Membrane electrode units (MEAs) are used, which consist of an ion-conducting Electrolyte membrane and optionally catalytically applied thereon effective electrodes (anode and cathode) exist.

From the prior art are as proton exchange membranes (PEMs) for Fuel cell electrolyte membranes made from organic polymers known to use acidic groups are modified, such as Nation® (DuPont, EP 0 956 604) sulfonated polyether ketones (Höchst, EP 0 574 791), sulfonated Hydrocarbons (Dais, EP 1 049 724) or those containing phosphoric acid Polybenzimidazole membranes (Celanese, WO 99/04445).

However, organic polymers have the disadvantage that the conductivity of  Water content of the membranes depends. Therefore, these membranes must be Use in the fuel cell can be swollen in water and although on the cathode Water is constantly being formed during operation of the membrane from the outside additional water can be added to dry out or decrease the To prevent proton conductivity. Typically organic Polymer membrane in a fuel cell both on the anode and cathode side in be operated in an atmosphere saturated with water vapor.

At elevated operating temperatures, electrolyte membranes made of organic Polymers are not used because at temperatures greater than about 100 ° C the water content in the membrane at atmospheric pressure is no longer guaranteed can be. The use of such membranes in a reformate or Direct methanol fuel cells are therefore generally not possible. In addition the polymer membranes when used in a direct methanol fuel cell show great permeability to methanol. Through the so-called cross-over from Methane oil on the cathode side can only have low power densities in the Realize direct methanol fuel cells.

Therefore, conventional organic polymer membranes are for use in one Reformat or direct methanol fuel cell despite the high proton conductivity in not usable in practice.

Inorganic proton conductors are e.g. B. from "Proton Conductors", P. Colomban, Cambridge University Press, 1992 known. However, for the purposes of a fuel cell, proton-conductive zirconium phosphates known from EP 0 838 258 show conductivities which are too low. On the other hand, in the case of defect perovskites, a usable proton conductivity is only achieved at temperatures which are above the operating temperatures of a fuel cell that occur in practice. Known proton-conducting MHSO ₄ salts are readily soluble in water and are therefore only of limited use for fuel cell applications in which water is formed in the fuel cell reaction (WO 00/45447).

Known inorganic proton-conducting materials also cannot be molded of thin membrane films that are used to provide a low Total cell resistance is required. Low sheet resistance and high Power densities of a fuel cell for technical applications in automotive engineering are therefore not possible with the known materials.

WO 99/62620 proposes an ion-conducting, permeable composite material and its use as an MEA electrolyte membrane in a fuel cell in front. The electrolyte membrane from the prior art consists of a metal network, which is coated with a porous ceramic material on the one proton conductive material was applied. This electrolyte membrane has an im Proton conductivity superior to an organic Nafion membrane Temperatures of more than 80 ° C. However, the prior art does not contain any Embodiment of a fuel cell in which such an electrolyte membrane was used.

It has now been found that the electrolyte membrane known from WO 99/62620 has serious disadvantages with regard to the usability of these MEA containing electrolyte membrane in practice and in view of that Manufacturing process required to provide such MEAs. By these disadvantages are the MEA known from WO 99/62620 for use in a Fuel cell unsuitable in practice. It has been shown that the known electrolyte membranes a good one at elevated temperatures Have proton conductivity, but on the other hand under practical Conditions of use occur in a fuel cell that shorts the Make electrolyte membranes unusable.

It is therefore an object of the present invention to provide a proton-conductive, flexible electrolyte membrane for a fuel cell which is suitable for use in practice and in particular

• a) high proton conductivity with significantly reduced air humidity in the Compared to polymer membranes,
• b) enables a low total resistance of a membrane electrode unit,  
• c) mechanical properties, such as tensile strength and flexibility, which for use under extreme conditions, such as when operating a Vehicle are suitable,
• d) tolerated increased operating temperatures of more than 80 ° C,
• e) avoids short circuits and cross-over problems, and
• f) can be easily manufactured.

This task is done with one for the reaction components of the fuel cells reaction impermeable, proton conductive, flexible electrolyte membrane for one Fuel cell solved according to claim 1. The present invention provides one Electrolyte membrane ready, which is a combination of a special Composite and a proton conductive material includes.

It has been found that the practical usability of a state of the art Technology known electrolyte membrane is related to the fact that the Ceramic coating of the metal net easily at the union points of the metal threads tears and thereby the conductive surface of the metal carrier is exposed. It a single very small crack in the ceramic coating is sufficient to remove the make the entire membrane unusable. Because of this, it is not possible the electrolyte membrane known from the prior art in one size manufacture that is required for use in a fuel cell without it under operating conditions, the ceramic coating is subjected to high stress comes, which destroys the membrane in a short time.

The present invention therefore proposes one for the reaction components of the Fuel cell reaction impermeable, proton conductive, flexible Electrolyte membrane for a fuel cell, comprising a permeable Composite material made of a flexible, openwork, glass-encased carrier and a porous ceramic material, the composite material having a proton conductive material is penetrated, which is suitable for the proton selectively To guide the membrane.

It has been found that, surprisingly, a practical and  especially insensitive to short circuits and cross-over problems Electrolyte membrane can be provided if as a material for the Membrane support a glass is chosen.

The electrolyte membrane of the present invention has the advantage that it is not in Water must be swelled to provide usable conductivity. It is therefore much easier to combine the electrodes and the electrolyte membrane To combine membrane electrode unit. In particular, there is no need for one to provide a swollen membrane with an electrode layer, as in the case of a Nafion membrane is necessary to prevent the electrode layer when Sources tears. The choice of the special carrier also ensures firm liability of the porous ceramic material on the carrier possible. This enables a stable MEA be manufactured that can withstand high mechanical loads. The good stability and conductivity of the invention Electrolyte membranes in a reformate or direct methanol fuel cell long service life and high power densities are also used provide low water partial pressures and high temperatures. Furthermore, it is possible the water balance of the new membrane electrode units through the Control the hydrophobicity / hydrophilicity of the membrane and electrodes. Through the targeted creation of nanopores in the membrane, the Take advantage of the effect of capillary condensation. A flooding of the electrodes Product water or a drying out of the membrane at a higher operating temperature or current density can be avoided in this way.

The glass of the carrier is preferably an aluminosilicate glass, a silicate glass or a Borosilicate glass, each of which may contain other elements. As another Magnesium is particularly preferred. The content of alkali metals should be as low as possible to ensure the stability of the glass under the operating conditions not endangered.

An aluminosilicate glass is particularly preferred. The glass preferably contains at least 50% by weight of SiO ₂ and optionally at least 5% by weight of Al ₂ O ₃ , preferably at least 60% by weight of SiO ₂ and optionally at least 10% by weight of Al ₂ O ₃ . In the event that the glass contains less than 60% by weight of SiO ₂ , the chemical resistance of the glass is likely to be too low and the carrier will be destroyed under the operating conditions. In the event that less than 10% by weight Al ₂ O _{3 is present} in the glass, the softening point of the glass may be too low and the technical manufacture of the composite membranes may therefore become very difficult.

Other elements in an aluminosilicate glass, silicate glass or borosilicate glass can be present are alkali metals, such as lithium, sodium, potassium, rubidium, or Cesium, alkaline earth metals such as magnesium, calcium, strontium or barium, as well Lead, zinc, titanium, arsenic, antimony, zirconium, iron, lanthanum, cerium, cadmium, or Halogens such as fluorine or chlorine.

A preferred glass composition for a support is as follows:
64-66% by weight SiO ₂ ,
24-25% by weight Al ₂ O ₃ ,
9-12% by weight of MgO,
<0.2% by weight CaO, Na ₂ O, K ₂ O, Fe ₂ O ₃

The support must be used both in the course of manufacturing the electrolyte membrane as well be stable under the operating conditions in a fuel cell. Hence the glass for the carrier preferably stable towards protons through the membrane be guided, the proton-conducting material with which the composite material is penetrated and the ceramic material with which the carrier is contacted. Further is the glass preferably also stable to the reaction medium with that of Carrier can come into contact if the ceramic coating of the carrier cracks having. It is therefore particularly preferred if the glass is not acidic contains leachable cations. On the other hand, leachable cations can be found in the glass if the stability of the support does not suffer, if cations by protons be replaced, for example, if the glass is suitable a gel layer on the To form a surface that protects the glass support from further attack by the acid.

It is also possible to use a glass, quartz or quartz glass that has a stability under operating conditions that is not sufficient for practical use. In this case, the surface of the carrier can be coated with a material that gives the carrier the necessary stability. An acid-resistant coating made of α-Al ₂ O ₃ , ZrO ₂ or TiO ₂ can be provided, for example, by a sol-gel process. A glass fabric (softening point: <800 ° C) with the following chemical composition is then available as material:
52-56 wt% SiO ₂
12-16% by weight Al ₂ O ₃ ,
5-10% by weight B ₂ O ₃ ,
16-25% by weight CaO,
0-5 wt% MgO
<2 wt% Na ₂ O + K ₂ O
<1.5% by weight of TiO ₂
<1 wt% Fe ₂ O ₃

The glass from which the carrier is made preferably has one Softening point of <800 ° C, particularly preferably <1000 ° C.

The weight loss in 10% HCl is preferably <4% by weight after 24 hours and after 168 h <5.5% by weight.

The flexible, openwork, glass-containing support may also be a material include, which is selected from ceramics, minerals, plastics, amorphous non-conductive substances, natural products, composite materials, composite materials or from at least a combination of these materials, provided that this Materials the usefulness of the electrolyte membrane according to the invention among the Do not affect operating conditions in a fuel cell. As a more flexible, Openwork, glass-enclosed carrier, a carrier can also be used become permeable by treatment with laser beams or ion beams have been done. The carrier of the composite material preferably comprises a fabric or fleece. The carrier preferably comprises fibers and / or filaments with a  Diameter from 1 to 150 microns, preferably 1 to 20 microns, and / or threads with a Diameter from 5 to 150 microns, preferably 20 to 70 microns.

In the event that the carrier is a fabric, then it is preferably around a fabric made of 11-Tex yarns with 5-50 warp or weft threads and especially 20-28 warps and 28-36 wefts. Very particularly preferred 5.5-Tex yarns with 10-50 warp or weft threads and preferably 20-28 Warp and 28-36 wefts.

The porous ceramic material preferably has pores with a medium one Diameter of at least 20 nm, preferably of at least 100 nm, entirely particularly preferably more than 500 nm. The ceramic material of the Composite preferably has a porosity of 10% to 60%, preferably from 20% to 45%.

The proton conductive material of an electrolyte membrane according to the invention comprises preferably a Bronsted acid, an immobilized hydroxysilylalkyl acid of Sulfur or phosphorus or a salt thereof, and / or an ionic liquid. These components impart proton conductivity to the electrolyte membrane. If necessary, the proton-conductive material can be an oxide of aluminum, Contain silicon, titanium, zirconium, and / or phosphorus. Such an oxide is at Use of a Bronsted acid essential. In the event that an immobilized Hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof, and / or If an ionic liquid is used, the additional oxide can be dispensed with become.

Bronsted acid can be sulfuric acid, phosphoric acid, perchloric acid, Nitric acid, hydrochloric acid, sulfurous acid, phosphorous acid as well Esters thereof and / or a monomeric or polymeric organic acid.

The electrolyte membrane according to the invention is preferably at least 80 ° C. preferably at least 120 ° C, and very particularly preferably at least 140 ° C, stable.  

The composite material of the electrolyte membrane preferably has a thickness in the range from 10 to 150 µm, preferably 10 to 80 µm, most preferably 10 to 50 µm.

The electrolyte membrane according to the invention preferably tolerates a bending radius of at least 100 mm, in particular of at least 20 mm and very particularly preferably of at least 5 mm.

The electrolyte membrane according to the invention exhibits at room temperature and at one relative air humidity of 35%, preferably a conductivity of at least 2 mS / cm, preferably at least 20 mS / cm, very particularly preferably 23 mS / cm on.

The following is the production of the electrolyte membranes according to the invention described.

An electrolyte membrane of the present invention is available from

• a) infiltration of a permeable composite material from a flexible, openwork, a glass support and a porous Ceramic material with an ionic liquid to make up the composite to create penetrating material that is suitable for selectively protons to guide the membrane, or
• b) Infiltration of a permeable composite material from a flexible, openwork, a glass-containing carrier and a porous ceramic material with
  • 1. a mixture containing an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof; or
  • 2. a mixture containing a Bronsted acid and / or an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and a sol which comprises a precursor for oxides of aluminum, silicon, titanium, zirconium and / or phosphorus and solidification of the composite infiltrating mixture,

and optionally infiltration of the composite material obtained after step (b) with an ionic liquid to create a material penetrating the composite create that is capable of selectively guiding protons through the membrane.

The electrolyte membranes of the present invention can be a special one Composite, which in general form and for another application from the PCT / EP 981 05 939 is known. This composite can be used with a proton-conducting material or a precursor thereof, whereupon the Dried membrane, solidified and optionally modified in a suitable manner so that an impermeable, ion / proton-conducting and flexible membrane is obtained. To manufacture the composite material, a glass is first used containing carrier according to PCT / EP98 / 05939 in a mechanical and thermal stable, permeable ceramic base membrane that neither electrically is still ion-conducting. Then this becomes porous, electrically insulating Basic membrane penetrated with the proton-conducting material.

A flexible, openwork, is used in the manufacture of the composite material Glass-containing carrier, contacted or infiltrated with a suspension, the one Contains precursor for the porous ceramic material. As a preliminary stage for the porous Ceramic material comes from at least one inorganic component Connection of a metal, a semi-metal or a mixed metal with one of the Elements of the 3rd to 7th main group in question as a suspension on the carrier can be applied and preferably solidified by heating. The Contact or infiltration can be done by printing, pressing, or pressing Roll up, knife, spread, dip, spray or pour.

The suspension with which the carrier is contacted preferably contains one inorganic component and a metal oxide sol, a semimetal oxide sol or a Mixed metal oxide sol or a mixture of these brines. Such a preferred Suspension can be achieved by suspending an inorganic component in a this brine can be produced.

Commercial sols such as titanium nitrate sol, zirconium nitrate sol or silica sol can be used  be used. However, the brine can also be obtained by hydrolysis of one Metal compound, semi-metal compound or mixed metal compound in one Medium, such as water, alcohol or an acid. As a compound to be hydrolyzed is preferably a metal nitrate, a metal chloride, a metal carbonate, a Metal alcoholate compound or a semimetal alcoholate compound, especially preferably at least one metal alcoholate compound, a metal nitrate, a metal chloride, a metal carbonate or at least one semimetal alcoholate compound is selected from the compounds of the elements Ti, Zr, Al, Si, Sn, Ce and Y or the Lanthanoids and actinoids, such as. B. titanium alcoholates such. B. titanium isopropylate, Silicon alcoholates, zirconium alcoholates, or a metal nitrate, such as. B. zirconium nitrate, hydrolysed. It may be advantageous to use at least half the hydrolysis Molar ratio of water, based on the hydrolyzable group of hydrolyzable Connection to perform. The hydrolyzed compound can be mixed with an acid, preferably with a 10 to 60% acid, preferably with a mineral acid, selected from sulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid and Nitric acid or a mixture of these acids can be peptized.

An inorganic component with a grain size of 1 to 10,000 nm can be suspended in the sol. An inorganic component which has a compound selected from metal compounds, semimetal compounds, mixed metal compounds and mixed metal compounds with at least one of the elements of the 3rd to 7th main group, or at least a mixture of these compounds, is preferably suspended. Particular preference is given to at least one inorganic component which comprises at least one compound from the oxides of the subgroup elements or from the elements of the 3rd to 5th main group, preferably oxides, selected from the oxides of the elements Sc, Y, Ti, Zr, Nb, Ce, V , Cr, Mo, W, Mn, Fe, Co, B, Al, In, Tl, Si, Ge, Sn, Pb and Bi, such as. B. Y ₂ O ₃ , ZrO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , SiO ₂ , Al ₂ O ₃ , suspended. The inorganic component can also be aluminosilicates, aluminum phosphates, zeolites or partially exchanged zeolites, such as, for. B. ZSM-5, Na-ZSM-5 or Fe-ZSM-5 or amorphous microporous mixed oxides, which can contain up to 20% non-hydrolyzable organic compounds, such as. B. vanadium oxide, silicon oxide glass or aluminum oxide-silicon oxide-methyl silicon sesquioxide glasses.

The mass fraction of the suspended component is preferably 0.1 to 500 times the hydrolyzed compound used.

By a suitable choice of the grain size of the suspended compounds in Depending on the size of the pores, holes or spaces of the support, but also by a suitable choice of the layer thickness of the composite material and the Proportional ratio of sol: solvent: metal oxide cracks in the Avoid composite material.

When using a mesh fabric with a mesh size of z. B. 100 microns suspensions can preferably be used to increase freedom from cracks, which is a suspended compound with a grain size of at least 0.7 microns having. In general, the ratio of grain size to mesh or Pore size from 1: 1000 to 50: 1000. The composite can preferably a thickness of 5 to 1000 microns, particularly preferably from 10 to 70 microns and very particularly preferably have from 10 to 30 microns. The suspension from sol and compounds to be suspended preferably have a ratio of solids to the compounds to be suspended from 0.1: 100 to 100: 0.1, preferably from 0.1: 10 to 10: 0.1 parts by weight.

After contacting the carrier, the suspension can be heated by heating the Composite of suspension and carrier are solidified to 50 to 1000 ° C. In a particular embodiment, the composite is for 10 seconds to 1 hour, preferably 10 seconds to 10 minutes, a temperature of 50 to 100 ° C. exposed. In a further special embodiment, the composite for 5 Seconds to 10 minutes, preferably 5 seconds to 5 minutes, especially preferably for 5 seconds to 1 minute, a temperature of 100 to 800 ° C. exposed. The composite can be heated with heated air, hot air, Infrared radiation, microwave radiation or electrically generated heat. In Another embodiment can thereby solidify the suspension achieved that the suspension is contacted with a preheated carrier and thus solidifies immediately after contacting.  

In a further special embodiment, the carrier is from a roll unrolled at a speed of 1 m / h to 1 m / s, on an apparatus that the Suspension contacted with the carrier and then to another apparatus, which enables the suspension to solidify by heating, and the like The composite material produced is rolled up on a second roll. In this way it is possible to manufacture the composite material continuously.

By repeatedly infiltrating a carrier with a suspension or a sol it is possible to manufacture composite materials with a certain pore size also to use carriers whose pore or mesh size for production a composite material with the required pore size is not suitable. This can e.g. B. the case when a composite material with a pore size of 0.25 microns produced using a carrier with a mesh size of over 300 microns shall be. To obtain such a composite, it can be advantageous to to bring the carrier first at least one suspension that is suitable carrier with to treat a mesh size of 300 microns, and this suspension after Apply to solidify. The composite material obtained in this way can now can be used as a carrier with a smaller mesh or pore size. On a further suspension can be applied to this carrier, which is a compound with a grain size of 0.5 microns.

The insensitivity to cracks in composite materials with large mesh or Pore sizes can also be improved by adding suspensions to the Carrier are applied, the at least two suspended compounds exhibit. Compounds to be suspended are preferably used which are a Grain size ratio of 1: 1 to 1:20, particularly preferably from 1: 1.5 to 1: 2.5 exhibit. The weight fraction of the grain size fraction with the smaller one Grain size should be at most 50%, preferably 20% and whole particularly preferably of 10% of the total weight of the used Do not exceed the grain size fraction.

The composite material is permeated with a proton-conducting material that is suitable to selectively conduct protons through the membrane and that of  Electrolyte membrane gives proton conductivity. The proton-conducting material can thereby after the production of the composite material or also during the Production of the composite material can be introduced into the ceramic material.

The proton conductive material can be a Bronsted acid, an immobilized Hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof, and / or an ionic liquid, and optionally an oxide of aluminum, silicon, Include titanium, zirconium, and / or phosphorus. As a suitable proton-conducting Material for the production of the electrolyte membrane can in particular all in the Proton-conducting materials described in WO 99/62620 can be used.

Starting from the permeable composite material, the method according to the invention for producing an electrolyte membrane can comprise in particular the following steps:

• a) infiltration of a permeable composite material from a flexible, openwork, a glass support and a porous Ceramic material with an ionic liquid to make up the composite to create penetrating material that is suitable for selectively protons to guide the membrane, or
• b) Infiltration of a permeable composite material from a flexible, openwork, a glass-containing carrier and a porous ceramic material with
  • 1. a mixture containing an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof; or
  • 2. a mixture containing a Bronsted acid and / or an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and a sol which comprises a precursor for oxides of aluminum, silicon, titanium, zirconium and / or phosphorus and solidification of the composite infiltrating mixture, and optionally infiltration of the composite material obtained in step (b) with an ionic liquid,

to create a material penetrating the composite that  selectively passing protons through the membrane is suitable.

The mixture containing a sol with which the composite material is infiltrated obtainable by hydrolysis of a hydrolyzable compound, preferably in one Mixture of water and alcohol to form a hydrolyzate, the hydrolyzable Compound is selected from hydrolyzable alcoholates, acetates, Acetylacetonates, nitrates, oxynitrates, chlorides, oxychlorides, carbonates, of Aluminum, silicon, titanium, zirconium, and / or phosphorus or esters, preferably Methyl esters, ethyl esters and / or propyl esters of phosphoric acid or phosphoric acid, and peptization of the hydrolyzate to that containing a sol Mixture.

It may be advantageous if the hydrolyzable compound is not hydrolyzable Bears groups in addition to hydrolyzable groups. Preferably, as such, too hydrolyzing compound an alkyltrialkoxy or dialkyl dialkoxy or Trialkylalkoxy compound of the element silicon used.

The mixture can be an acid or base which is soluble in water and / or alcohol be added. An acid or base of the elements Na, Mg, K, Ca, V, Y, Ti, Cr, W, Mo, Zr, Mn, Al, Si, P or S added.

The mixture can also be non-stoichiometric metal or semi-metal Include non-metal oxides or hydroxides by changing the Oxidation level of the corresponding element were generated. The change in Oxidation stage can be achieved by reaction with organic compounds or inorganic compounds or by electrochemical reactions. The change in the oxidation state is preferably carried out by reaction with a Alcohol, aldehyde, sugar, ether, olefin, peroxide or metal salt. Connections on this way change the oxidation level are z. B. Cr, Mn, V, Ti, Sn, Fe, Mo, W or Pb.

Substances can also be added to the mixture which are used to form lead inorganic ion-conducting structures. Such substances can e.g.  Zeolite and / or β-aluminosilicate particles.

The permeable composite material can also be treated with a Silane ionic be equipped. For this, a 1 to 20% solution of this silane is used prepared in a solution containing water and the composite material immersed. Aromatic and aliphatic alcohols, aromatic and aliphatic hydrocarbons and other common solvents or mixtures can be used. It is advantageous to use ethanol, octanol, Toluene, hexane, cyclohexane and octane. After draining the adhering liquid the soaked composite material is dried at approx. 150 ° C and can either directly or after repeated subsequent coating and drying at 150 ° C can be used as an ion-conducting, permeable composite material. Suitable for this silanes carrying both cationic and anionic groups. In the event of proton-conducting materials, sulfonic or phosphonic acid groups are preferred.

It may also be advantageous if the solution or suspension is for treatment the composite material in addition to a trialkoxysilane also acidic or basic Compounds and water includes. Preferably, the acidic or basic compounds at least one Brönstedt or known to the expert Lewis acid or base.

The mixture with which the composite material is infiltrated can contain further proton-conducting substances, preferably titanium phosphates, titanium phosphonates, zirconium phosphates, zirconium phosphonates, iso- and heteropoly acids, nanocrystalline and / or crystalline metal oxides, with Al ₂ O ₃ -, ZrO ₂ -, TiO ₂ - or SiO ₂ - Powder are preferred. Examples of iso- and heteropolyacids are tungsten phosphoric acid and silicon tungstic acid.

The infiltration of the composite material can be done by printing, pressing, Pressing in, rolling up, knife coating, spreading on, dipping, spraying or pouring on the Mix on the permeable composite material. Infiltration with the Mixing can be repeated. If necessary, a Drying step, preferably at an elevated temperature in a range of  50 to 200 ° C, between repeated infiltration. In a preferred one In one embodiment, the permeable composite material is infiltrated continuously. It may be advantageous for the composite to be used for infiltration is preheated.

The mixture can be solidified in the composite material by heating to a temperature of 50 to 800 ° C, preferably 100 to 600 ° C, very particularly preferably 150 to 200 ° C, the heating by heated air, hot air, Infrared radiation or microwave radiation can take place.

However, the electrolyte membrane can also be made using a sol containing a ion-conducting material or a material that after further treatment has ion-conducting properties in the manufacture of the composite material be preserved. Materials are preferably added to the sol, which are used for formation of inorganic ion-conducting layers on the inner and / or outer Lead surfaces of the particles contained in the composite.

An acidic and / or basic group can be used to produce the electrolyte membrane containing trialkoxysilane solution or suspension is used. Preferably at least one of the acidic or basic groups is a quaternary ammonium, Phosphonium, alkyl sulfonic acid, carboxylic acid or phosphonic acid group.

A membrane electrode unit according to the invention is described below. The flexible membrane electrode unit for a fuel cell comprises one Anode layer and a cathode layer, each on opposite sides one impermeable to the reaction components of the fuel cell reaction, Proton-conductive, flexible electrolyte membrane intended for a fuel cell are, wherein the electrolyte membrane from a permeable composite material a flexible, openwork, glass and porous support Ceramic material comprises, wherein the composite material with a proton conductive Material is penetrated, which is capable of selectively guiding protons through the membrane, and wherein the anode layer and the cathode layer are porous and one each Catalyst for the anode and cathode reaction, a proton conductive  Component and optionally include a catalyst support.

The proton-conductive component of the anode and / or cathode layer and / or the proton-conductive material of the composite material preferably each comprises

• a) an immobilized hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof, and optionally an oxide of aluminum, Silicon, titanium, zirconium and / or phosphorus, and / or
• b) a Bronsted acid and an oxide of aluminum, silicon, titanium, Zirconium, and / or phosphorus and optionally
• c) inorganic oxides, phosphates, phosphides, phosphonates, sulfates, Sulfonates, vanadates, antimonates, stannates, plumbates, chromates, Tungsten, molybdates, manganates, titanates, silicates, aluminosilicates and aluminates of the elements lithium, sodium, potassium, magnesium, Calcium, aluminum, silicon, titanium, zirconium, yttrium, phosphorus Vanadium, tungsten, molybdenum, chrome, manganese, iron, cobalt, nickel, Copper, zinc or cerium or a combination of these elements,

and comprises the proton conductive material of the composite optionally an ionic liquid containing a Bronsted acid can.

In a preferred embodiment, the hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof is an organosilicon compound of the general formulas

[{(RO) _y (R ² ) _z } _a Si {R ¹ -SO ₃ ^- } _a ] _x M ^{x +} (I)

or

[(RO) _y (R ² ) _z Si {R ¹ -O _b -P (O _c R ³ ) O ₂ ^- } _a ] _x M ^{x +} (II)

where R ^{1 is} a linear or branched alkyl or alkylene group having 1 to 12 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms or a unit of the general formulas

stands,
where n, m each represents an integer from 0 to 6,
M represents H, NH ₄ or a metal,
x = 1 to 4,
y = 1 to 3, z = 0 to 2 and a = 1 to 3, with the proviso that y + z = 4 - a,
b, c = 0 or 1,
R, R ^{2 are the} same or different and stand for methyl, ethyl, propyl, butyl radicals or H.
and
R ^{3 represents} M or a methyl, ethyl, propyl or butyl radical.

The hydroxysilylalkyl acid of sulfur or phosphorus is preferred Trihydroxysilylpropylsulfonic acid, trihydroxysilylpropylmethylphosphonic acid or Dihydroxysilylpropylsulfondisäure. The hydroxysilylalkyl acid is preferably the Sulfur or phosphorus or a salt thereof with a hydrolyzed compound phosphorus or a hydrolyzed nitrate, oxynitrate, chloride, oxychloride, Carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal immobilized. In a further preferred embodiment, the Hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof a hydrolyzed compound obtained from titanium propylate, titanium ethylate, Tetraethyl orthosilicate (TEOS) or tetramethyl orthosilicate (TMOS), zirconium nitrate, Zirconium oxynitrate, zirconium propylate, zirconium acetate, zirconium acetylacetonate, Phosphoric acid methyl ester, diethyl phosphite (DEP) or diethyl ethyl phosphonate (DEEP) immobilized.  

Advantageously, the composite impregnated with a proton conductive material can additionally contain an ionic liquid which comprises a cation which is selected from the imidazolium ions, pyridinium ions, ammonium ions or phosphonium ions of the following formulas:

where R and R 'can be identical or different and represent alkyl, olefin or aryl groups or are hydrogen,
and wherein the ionic liquid comprises an anion which is selected from the following ions: nitrate, sulfate, hydrogen sulfate, chloroaluminations, BF ₄ ^- , alkyl borate ions, preferably triethylhexyl borate, halogenophosphate ions, preferably PF ₆ ^- .

The membrane electrode assembly according to the invention can preferably be in a Fuel cell at a temperature of at least 80 ° C, preferably at operated at least 120 ° C, and very particularly preferably at least 140 ° C can be. The membrane electrode assembly according to the invention preferably tolerates a bending radius of at least 100 mm, in particular of at least 20 mm, very particularly preferably tolerated by at least 5 mm.

In a special embodiment of the membrane according to the invention electrode unit have the proton conductive component of the anode layer and Cathode layer and the proton conductive material of the electrolyte membrane same composition. On the other hand, it is also possible that only the Anode layer and the cathode layer have the same composition or that the anode layer and the cathode layer different catalysts exhibit. In a preferred embodiment, the catalyst support is in the Anode layer and electrically conductive in the cathode layer.

To manufacture the membrane electrode assembly, an electrolyte membrane is inserted through a  suitable method with the optionally catalytically active electrode material coated.

The electrolyte membrane can be provided with the electrode in various ways become. The way as well as the order of how the electrically conductive Material, catalyst, electrolyte and possibly other additives applied to the membrane be at the discretion of the expert. It is only important to ensure that the Interface gas space / catalyst (electrode) / electrolyte is formed. In one special case is on the electrically conductive material as a catalyst carrier waived, in this case the electrically conductive catalytic converter takes care of the Deriving the electrons from the membrane electrode assembly.

To manufacture the membrane electrode assembly, a special Embodiment on the electrolyte membrane the catalytically active (Gas diffusion) electrodes built. For this, an ink from a soot Catalyst powder and at least one proton conductive material. The Ink can also contain other additives that improve the properties of the Improve the membrane electrode assembly. The soot can also be electric by others conductive materials (such as metal powder, metal oxide powder, carbon, coal) be replaced. In a special embodiment, is used as a catalyst support a metal or semimetal oxide powder (such as Aerosil) is used for soot. This Ink is then, for example, by screen printing, scraping, spraying, rolling or applied to the membrane by dipping.

The ink can contain any ion-conducting material that is also used to infiltrate the composite. The ink can thus contain an acid or its salt, which is immobilized by a chemical reaction in the course of a solidification process after the ink has been applied to the membrane. So this acid can e.g. B. simple Bronsted acid, such as sulfuric or phosphoric acid, or a silylsulfonic or silylphosphonic acid. As materials that support the solidification of the acid, for. B. Al ₂ O ₃ , SiO ₂ , ZrO ₂ , TiO ₂ are used, which are also added via molecular precursors of the ink.

In contrast to the proton conductive material of the composite material, which for the Reaction components of the fuel cell reaction must be impermeable, Both the cathode and the anode must have a large porosity so that the Reaction gases, such as hydrogen and oxygen, without inhibiting mass transfer to the Interface between catalyst and electrolyte can be brought up. This Porosity can be achieved, for example, by using metal oxide particles a suitable particle size and of organic pore formers in the ink or by a suitable proportion of solvent in the ink.

A medium comprising the following components can be used as a special ink:

• 1. a condensable component, which after the condensation of a Anode layer or a cathode layer of a membrane electrode assembly gives proton conductivity to a fuel cell,
• 2. a catalyst that the anode reaction or the cathode reaction in one Catalyzed fuel cell, or a precursor compound of the catalyst,
• 3. optionally a catalyst support
• 4. optionally a pore former, and
• 5. optionally additives to improve foam behavior, viscosity and liability.

The condensable component which imparts proton conductivity to the anode layer or the cathode layer after the condensation is preferably selected from

• A) hydrolyzable compound of phosphorus and / or hydrolyzable nitrates, oxynitrates, chlorides, oxychlorides, carbonates, Alcoholates, acetates, acetylacetonates of a metal or semimetal, preferably aluminum alcoholates, vanadium alcoholates, titanium propylate, Titanium ethylate, zirconium nitrate, zirconium oxynitrate, zirconium propylate, Zirconium acetate or zirconium acetylacetonate, and / or Metal acids of aluminum, titanium, vanadium, antimony, tin, lead, Chromium, tungsten, molybdenum, manganese, being tungsten phosphoric acid and Silicotungstic acid are preferred and or  
• B) an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and in a particularly preferred embodiment additionally a hydroxysilylalkyl acid of sulfur or phosphorus or their salt immobilizing hydrolyzable compound of phosphorus or a hydrolyzable nitrate, oxynitrate, chloride, oxychloride, carbonate, alcoholate, Acetate, acetylacetonate of a metal or semimetal, preferably Phosphoric acid methyl ester, diethyl phosphite (DEP), diethyl ethyl phosphonate (DEEP) titanium propylate, titanium ethylate, tetraethyl orthosilicate (TEOS) or Tetramethyl orthosilicate (TMOS), zirconium nitrate, zirconium oxynitrate, Zirconium propylate, zirconium acetate or zirconium acetylacetonate.

However, to increase proton conductivity, the ink can also contain nanoscale oxides, such as B. of aluminum, titanium, zirconium or silicon, or zirconium or Contain titanium phosphates or phosphonates.

The catalyst or precursor compound of the catalyst preferably comprises Platinum or a platinum alloy and optionally a cocatalyst, the Cocatalyst is a transition metal complex of phthalocyanine or substituted Is phthalocyanine. The catalyst precursor preferably comprises Platinum, palladium and / or ruthenium. The transition metal complex of the Cocatalyst preferably comprises nickel and / or cobalt.

The pore former that may be contained in the ink may be an organic one and / or inorganic substance that is at a temperature between 50 and 600 ° C and preferably decomposed between 100 and 250 ° C. In particular, the inorganic pore formers ammonium carbonate or ammonium bicarbonate.

The catalyst support which is optionally contained in the ink is preferred electrically conductive and preferably contains carbon black, metal powder, metal oxide powder, Carbon or coal.

In a further embodiment, a prefabricated gas distributor, which the  Gas diffusion electrode consisting of an electrically conductive material (e.g. a contains porous carbon fleece) catalyst and electrolyte, directly on the membrane be applied. In the simplest case, the gas distributor and are fixed Membrane by a pressing process. For this it is necessary that membrane or Gas distributors have thermoplastic properties at the pressing temperature. The The gas distributor can also be fixed to the membrane with an adhesive. This adhesive must have ion-conducting properties and can, in principle, consist of the material classes already mentioned above. For example, as Adhesive a metal oxide sol can be used, which also contains a hydroxysilyl acid contains. Finally, the gas distributor can also "in situ" at the last stage of the Membrane or gas diffusion electrode manufacture can be applied. In this The proton-conducting material in the gas distributor or in the membrane is not yet stage cured and can be used as an adhesive. The gluing process takes place in both Precipitation by gelation of the sol followed by drying / solidification.

However, it is also possible to deposit the catalyst directly on the membrane and with an open-pore gas diffusion electrode (such as an open-pore coal paper). For this, e.g. B. a metal salt or an acid on the Surface applied and reduced to metal in a second step. So For example, platinum can be applied via hexachloroplatinic acid and used for Reduce metal. In the last step, the lead electrode is pressed or fixed with an electrically conductive adhesive. The solution that the Contains metal precursor, can additionally contain a compound that already is proton-conductive or at least ion-conductive at the end of the manufacturing process is. Suitable materials come again from those already mentioned above ion-conducting substances in question.

In this way, a membrane electrode assembly is obtained which is in a Fuel cell, especially in a direct methanol fuel cell or one Reformat fuel cell can be used.

The electrolyte membrane according to the invention and the one according to the invention Membrane electrode unit can in particular be used to manufacture a fuel cell  or a fuel cell stack can be used, the fuel cell in particular a direct methanol fuel cell or a reformate fuel cell that is used in a vehicle.

The invention is explained in more detail below with the aid of examples.

EXAMPLES 3 Production Example 1 Production of suspensions Production example 1.1

120 g of titanium tetraisopropylate are mixed with 140 g of deionized ice with vigorous stirring stirred until the precipitate is finely distributed. After adding 100 g of 25% hydrochloric acid is stirred until the phase becomes clear. Subsequently 280 g of aluminum oxide of the type CT300OSG from Alcoa, Ludwigshafen, added and stirred for several days until the aggregates dissolved. This Suspension can then be used to make a composite or as Precursor for a proton-conducting material can be used.

Production example 1.2

80 g of titanium tetraisopropylate are hydrolyzed with 20 g of water and the resulting one Precipitation is peptized with 120 g of nitric acid (25%). This solution is up stirred to clear and after adding 40 g of titanium dioxide from Degussa (P25) is stirred until the agglomerates dissolve. This suspension can then for the production of a composite material or as a preliminary stage for a proton-conducting Material can be used.

Production example 1.3

90 g of titanium isopropylate are mixed with 40 g of ethanol and with 10 g of water hydrolyzed. The gel that precipitates is mixed with 80 g of a 30% sulfuric acid peptized and after complete dissolution of the gel 30 g of aluminum oxide Degussa added and stirred until the agglomerates dissolve. This  Suspension can then be used to make a composite or as Precursor for a proton-conducting material can be used.

Production example 1.4

50 g of titanium tetraethoxylate were hydrolyzed with 270 g of water and with 30 g Nitric acid (25%) peptized. Then 100 g of ethanol and 350 g of CT 2000 SG from Alcoa added and stirred. This suspension can then for the production of a composite material or as a preliminary stage for a proton-conducting Material can be used.

Production example 1.5

40 g of titanium isopropylate and 30 g of methyltriethoxysilane are mixed with 60 g of ethanol and hydrolyzed with 10 g of water. The gel which precipitates is 60% 30% Hydrochloric acid peptized and after complete dissolution of the gel 90 g amorphous microporous mixed oxides (cf. DE 195 45 042) are added and by Dissolve the agglomerates stirred. This suspension can then be used Manufacture of a composite material or as a preliminary stage for a proton-conducting Material can be used.

Production example 1.6

80 g of titanium tetraisopropylate are hydrolyzed with 20 g of water and the resulting one Precipitation is peptized with 120 g of nitric acid (25%). This solution is up stirred to clear and after adding 20 g of titanium dioxide from Degussa (P25) and 40 g of titanium dioxide in the anatase form until the agglomerates dissolve touched. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material become.

Production example 1.7

40 g of titanium tetraisopropylate are hydrolyzed with 20 g of water and the resulting one Precipitation is peptized with 60 g of nitric acid (25%). This solution is up stirred to clear and after addition of 40 g of tin oxide from Aldrich is until stirred to dissolve the agglomerates. This suspension can then be used  Manufacture of a composite material or as a preliminary stage for a proton-conducting Material can be used.

Production example 1.8

80 g of titanium tetraisopropylate are hydrolyzed with 40 g of water and the resulting one Precipitation is peptized with 120 g of hydrochloric acid (25%). This solution will last until Are stirred clear and after adding 200 g of titanium dioxide from Bayer stirred to dissolve the agglomerates. This suspension can then be used Manufacture of a composite material or as a preliminary stage for a proton-conducting Material can be used.

Production example 1.9

120 g of titanium tetraisopropylate are mixed with 140 g of deionized ice with vigorous stirring stirred until the precipitate is finely distributed. After adding 100 g of 25% nitric acid is stirred until the phase becomes clear and 280 g Alumina of the type CT3000SG from Alcoa, Ludwigshafen, added and stirred for several days until the aggregates dissolved. This suspension can then for the production of a composite material or as a preliminary stage for a proton conducting material can be used.

Production example 1.10

20 g titanium tetraisopropylate and 120 g titanium hydroxide hydrate (S500-300, test product from Rhone-Poulenc were hydrolyzed or dissolved with 45 g of water and with 50 g peptized with a 25% hydrochloric acid. After clearing and adding 300 g Alumina (7988 E330, Norton Materials) and 50 g of iron (III) chloride stirred until the agglomerates dissolve. This suspension can then be used Manufacture of a composite material or as a preliminary stage for a proton-conducting Material can be used.

Production example 1.11

6 g of titanium tetrachloride were hydrolyzed with 10 g of 25% hydrochloric acid. To Clear and add 13 g of aluminum oxide (7988 E330, Norton Materials) and 2 g of ruthenium chloride were stirred until the agglomerates dissolved.  

This suspension can then be used to produce a composite or can be used as a precursor for a proton-conducting material.

Production example 1.12

100 g of silica sol (Levasil 200, from Bayer AG) were mixed with 180 g of aluminum oxide AA07 from Sumitomo Chemical until the agglomerates have dissolved. This Suspension can then be used to make a composite or as Precursor for a proton-conducting material can be used.

Production example 1.13

70 g of tetraethoxysilane are hydrolyzed with 20 g of water and the resulting one Precipitation is peptized with 120 g of nitric acid (25%). This solution is up stirred to clear and after adding 40 g of amorphous silica or amorphous silicon dioxide from Degussa until the agglomerates dissolve touched. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material become.

Preparation example 1.14

20 g of aluminum triisopropylate are placed in 10 g of ethanol and with 5 g of water hydrolyzed. The resulting gel is peptized with 45 g of nitric acid (15%) and stirred until the gel completely dissolves. After adding 60 g Vanadium pentoxide from Aldrich is used until the agglomerates are completely dissolved touched. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material become.

Production example 1.15

20 g of zirconium tetraisopropylate are hydrolyzed with 15 g of water and the resulting precipitate is peptized with 30 g of nitric acid (25%). To the precipitate is completely dissolved after adding 60 g of zeolite Y (type CBV 780 from Zeolyst) until the agglomerates are completely dissolved. This Suspension can then be used to make a composite or as  Precursor for a proton-conducting material can be used.

Preparation example 1.16

20 g of zirconium tetraisopropylate are hydrolyzed with 15 g of water and the resulting precipitate is peptized with 30 g of nitric acid (25%). To The precipitate is completely dissolved after the addition of 10 g of zirconium dioxide from Degussa (particle size 50 run) until the agglomerates are completely dissolved touched. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material become.

Production example 1. 17

20 g of zirconium tetraisopropylate are hydrolyzed with 15 g of water and the resulting precipitate is peptized with 30 g of nitric acid (25%). To the precipitate is completely dissolved after the addition of 60 g of corundum powder Particle size 10 micrometers (Amperit, HC Stark) until the Agglomerates stirred. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material become.

Production example 1.18

20 g of zirconium nitrate sol (30% from MEL Chemicals were mixed with 150 g of water, 25 g Titanium dioxide (Finntianx 78173 from Kemira Pigments and 210 g glass powder (HK, the Robert Reidt) stirred. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material become.

Production example 1.19

10 g of zirconium nitrate sol (30% from MEL Chemicals and 50 g Titanium dioxide filter cake, test product from Sachtzleben was charged with 150 g Water, 290 g of aluminum oxide 71340 RA from Nabaltec until the Agglomerates stirred. This suspension can then be used to produce a Composite or used as a precursor for a proton conductive material  become.

Production example 1.20

120 g of zirconium tetraisopropylate are mixed with 140 g of deionized ice under vigorous Stir until the precipitate is finely divided. To The addition of 100 g of 25% hydrochloric acid is stirred until the phase becomes clear and 280 g of α-aluminum oxide of the type CT3000SG from Alcoa, Ludwigshafen, were added and stirred for several days until the aggregates dissolved. This Suspension can then be used to make a composite or as Precursor for a proton-conducting material can be used.

Production Example 2 Manufacture of composite materials Production example 2.1

A suspension according to Example 1.9 is placed on a square mesh fabric made of glass (65% by weight SiO ₂ , 25% by weight Al ₂ O ₃ , 10% by weight MgO, <0.2% by weight CaO, Na ₂ O. , K ₂ O, Fe ₂ O ₃ ; 11-Tex yarn with 24 warp and 32 weft threads) with a mesh size of 90 µm and by blowing with hot air at a temperature of 550 ° C within 10 seconds dried. A flat composite material was obtained which can be used as a composite material with a pore size of 0.2 to 0.4 µm. The composite material can be bent to a radius of 5 mm without the composite material being destroyed. The composite material can be used to produce an electrolyte membrane according to the invention.

Production example 2.2

A suspension according to preparation example 1.2 was applied to one as in example 2.1 Composite described by rolling up with a layer thickness of 5 microns applied. The suspension was solidified again by blowing the Compound with 550 ° C hot air for a period of about 5 seconds. It became a Composite obtained, which had a pore size of 30-60 nm and for Production of an electrolyte membrane according to the invention is suitable.  

Production examples 2.3 to 2.19

The suspensions of Preparation Examples 1.3 to 1.19 are each based on the in Production example 2.1 described carrier applied and by blowing with Air dried at a temperature of 450-550 ° C for a few seconds. The Composite material obtained can be used to produce an inventive Composite membrane are used.

Production example 2.20

The suspension produced according to production example 1.20 is in a thin layer applied to a glass fabric (11-Tex yarn with 28 warp and 32 weft threads) and solidified at 550 ° C within 5 seconds. The composite material obtained can can be used to produce a composite membrane according to the invention.

example 1 Production of an electrolyte membrane by treatment of a composite material with silanes

An inorganic permeable composite made by Application of a thin layer of the suspension from preparation example 1.1 a glass support according to Production Example 2.1 was immersed in a solution that consisted of the following components: 5% Degussa Silan 285 (a Propylsulfonic acid triethoxysilane), 20% deionized (VE) water in 75% ethanol. The solution had to be stirred at room temperature for 1 h before use.

After draining off the supernatant solution, the composite material was at 80 to 150 ° C. dried to provide an electrolyte membrane of the present invention.

Example 2 Production of an electrolyte membrane

20 g of aluminum alcoholate and 17 g of vanadium alcoholate were mixed with 20 g of water hydrolyzed and the resulting precipitate was treated with 120 g of nitric acid (25%) peptized. This solution was stirred until clear and after adding 40 g  Titanium dioxide from Degussa (P25) was still until all agglomerates dissolved touched. After adjusting the pH to about 6, the suspension was opened a composite material produced according to production example 2.1 and dried to a proton conductive with negative fixed charges To create electrolyte membrane.

Examples 3 and 4 Production of an electrolyte membrane with zeolites

10 g methyltriethoxisilane, 30 g tetraethylorthosiloxane and 10 g aluminum trichloride were hydrolyzed with 50 g water in 100 g ethanol. For this purpose, 190 g Zeolite USY (CBV 600 from Zeolyst). It was stirred until all agglomerates had dissolved and then the suspension was opened a composite material produced according to production example 2.1 or 2.2 painted and solidified by heat treatment at 600 ° C to a to create proton-conducting electrolyte membrane.

Example 5 Production of an electrolyte membrane

10 ml of anhydrous trihydroxysilylpropylsulfonic acid, 30 ml of ethanol and 5 ml of water are mixed by stirring. 40 ml of TEOS (tetraethyl orthosilicate) are slowly added dropwise to this mixture with stirring. For condensation, this sol is stirred in a closed vessel for 24 h. The composite material from production example 2.20 is immersed in this sol for 15 minutes. The sol is then allowed to gel in the impregnated membrane for 60 minutes in air and dry. The membrane filled with the gel is dried at a temperature of 150 ° C. for 60 minutes, so that the gel solidifies and becomes water-insoluble. In this way a dense membrane is obtained which has a proton conductivity at room temperature and normal ambient air of approx. 2.10 ^-3 S / cm.

Example 6 Production of an electrolyte membrane

In 50 ml of the sol from Example 5, an additional 25 g of tungsten phosphoric acid solved. In this sol, the composite material from production example 2.1 is left for 15 minutes dipped. Then proceed as in Example 5.

Example 7 Production of an electrolyte membrane

100 ml of titanium isopropylate is added dropwise to 1200 ml of water with vigorous stirring. The The resulting precipitate is aged for 1 h and then concentrated with 8.5 ml Added nitric acid and peptized at the boil for 24 h. In 25 ml of this sol 50 g of tungsten phosphoric acid are dissolved. A further 25 ml is added to this solution Trihydroxysilylpropylsulfonic acid and stirred for one hour at room temperature. In this sol is then the composite material from production example 2.1 for 15 min immersed. Then the membrane is dried and through a Heat treatment solidified at 150 ° C and into the proton-conducting form transferred.

Example 8 Production of an electrolyte membrane

Sodium trihydroxysilylmethylphosphonate dissolved in a little water is mixed with ethanol diluted. The same amount of TEOS is added to this solution and stirring is continued briefly. In this sol, the composite material from production example 2.1 is left for 15 minutes immersed. Then the membrane is dried and through a Heat treatment solidified at 250 ° C and by an acid treatment in the proton conductive form.

Example 9 Production of an electrolyte membrane

10 g of methyltriethoxisilane, 30 g of tetraethylorthosilicate and 10 g of aluminum trichloride are hydrolyzed with 50 g of water in 100 g of ethanol. Become this mixture then 190 g of zeolite USY (CBV 600 from Zeolvst) added. It will still be there  stirred until all agglomerates have dissolved and then the Brush suspension on a composite material prepared according to Example 2.20 and solidified by a temperature treatment at 500 ° C and into the ion-conducting Membrane transferred.

Examples 10 to 14 Production of an electrolyte membrane by infiltrating a proton-conducting Membrane with an ionic liquid

A porous electrolyte membrane according to Examples 5 to 9 is sprayed with [EMIM] CF ₃ SO ₃ (EMIM: 1-ethyl-3-methylimidazolium) as the ionic liquid. Spraying is carried out from one side of the composite material until the opposite side of the composite material is also wetted by the ionic liquid which has passed through the composite material. In this way it is achieved that the air contained in the porous ion-conducting composite material is displaced by the ionically conductive liquid. This membrane can be allowed to air dry after wiping off excess ionic liquid. The ionic liquid is retained in the membrane according to the invention by capillary forces. Since ionic liquids have no measurable vapor pressure, a reduction in the ionic liquid in the membrane cannot be expected even after the membrane produced according to the invention has been stored for a long time.

Examples 15 to 74 Production of an electrolyte membrane by infiltrating a proton-conducting Membrane with an ionic liquid

Instead of the [EMIM] CF ₃ SO ₃ from Examples 10 to 14, the twelve ionic liquids according to [EMIM] CF ₃ SO _{3 are used} according to the following table:

The abbreviations have the following meaning:
EMIM = 1-ethyl-3-methylimidazolium ion, BMIM = 1-n-butyl-3-methylimidazolium ion, MMIM = 1-methyl-3-methylimidazolium ion, Ts = H ₃ CC ₆ H ₄ SO ₂ (tosyl ), Oc = octyl, Et = ethyl, Me = methyl, Bu = n-butyl, CF ₃ SO ₃ = triflate anion and Ph = phenyl.

Example 75

<; H 07782 00070 552 001000280000000200012000285910767100040 0002010115928 00004 07663E1 <Production of an electrolyte membrane by immobilizing a Bronsted acid

A TEOS solution consisting of TEOS: ethanol: H ₂ O: HCl = 1: 8: 4: 0.05 mol is precondensed for 24 h. Then give 20 vol% conc. HClO ₄ (70%) to the sol and after briefly stirring by knife coating it with a base membrane, which was produced according to Preparation Example 2.20. Following the infiltration, the membrane is solidified at RT and dried. The conductivity of the membrane at room temperature and approx. 35% r. F. is approx. 20 mS / cm.

Example 76 Production of an electrolyte membrane by immobilizing a Bronsted acid

An electrolyte membrane was produced as in Example 75, H ₂ SO ₄ (98% strength) being added to the sol instead of HClO ₄ as acid. Under the same measurement conditions (room temperature and approx. 35% RH), the conductivity is about 23 mS / cm after a thermal treatment of 100 ° C (1 h).

Example 77 Production of an electrolyte membrane by immobilizing a Bronsted acid

A TEOS sol consisting of TEOS (11 ml), diethyl phosphite (19 ml), ethanol (11 ml) and H ₃ PO ₄ (10 ml) is precondensed for one hour and then a basic membrane, which was produced according to Preparation Example 2.20 , infiltrated by doctor blade. The membrane is dried at 150 ° C for 1 h. The conductivity of the membrane at room temperature and approx. 35% rh is around. 2.9 mS / cm.

Example 78 Production of an electrolyte membrane by immobilizing a Bronsted acid

100 ml of titanium isopropoxide are dropped into 1200 ml of water with vigorous stirring. The resulting precipitate is aged for 1 h and then concentrated with 8.5 ml. HNO _{3 was} added and peptized at the boil for 24 h. 10 ml of H ₂ SO ₄ (98%) are added to 100 ml of this sol. After coating the base membrane 2.20 with such a sol and solidifying at temperatures of up to approximately 150 ° C., the proton-conducting membrane is obtained.

Example 79 Production of an anode ink

10 ml of anhydrous trihydroxysilylpropylsulfonic acid, 60 ml of ethanol and 5 ml of water are mixed by stirring. 40 ml of TEOS (tetraethyl orthosilicate) are slowly added dropwise to this mixture with stirring. The catalyst known from DE 197 21 437 and DE 198 16 622 is dispersed in this sol so that a degree of catalyst coverage of about 0.2 mg / cm ² or 0.5 mg / cm ² can be achieved in the electrode.

Example 80 Production of an anode ink

100 ml of titanium isopropoxide are dropped into 1200 ml of water with vigorous stirring. The resulting precipitate is aged for 1 h and then concentrated with 8.5 ml. HNO _{3 was} added and peptized at the boil for 24 h. 50 g of tungsten phosphoric acid are dissolved in 50 ml of this sol and the catalyst is then dispersed therein as described in Example 79.

Example 81 Production of an anode ink

20 g of aluminum alcoholate and 17 g of vanadium alcoholate are mixed with 20 g of water hydrolyzed and the resulting precipitate is treated with 120 g of nitric acid (25%) peptized. This solution is stirred until clear and after adding 40 g Titanium dioxide from Degussa (P25) is still until all agglomerates are dissolved touched. After setting a pH of approx. 6, the catalyst is as in Example 79 described dispersed therein.

Example 82 Production of a cathode ink

10 ml of anhydrous trihydroxysilylpropylsulfonic acid, 60 ml of ethanol and 5 ml of water are mixed by stirring. 20 ml of TEOS (tetraethyl orthosilicate) and 20 ml of methyltriethoxysilane are slowly added dropwise to this mixture with stirring. The catalyst used in DE 196 11 510 or the one used in DE 198 12 592 is dispersed in this sol, so that a Pt coverage of about 0.15 mg / cm ² or 0.25 mg / cm ² can be achieved in the electrode ,

Example 83 Production of a cathode ink

20 g methyltriethoxysilane, 20 g tetraethyl orthosilicate and 10 g aluminum trichloride are hydrolyzed with 50 g of water in 200 g of ethanol. For this purpose, 190 g of zeolite USY (CBV 600 from Zeolyst). It is stirred until everyone is happy Agglomerates have dissolved and then the catalyst as in Example 82 described dispersed therein.

Example 84 Manufacture of a membrane electrode assembly

A membrane according to Example 1 is screen printed with the ink according to Example 79 first printed on the front. This page serves in the later Membrane electrode unit as an anode. The printed membrane is at one Dried temperature of 150 ° C. In addition to the escape of the solvent, it happens at the same time as immobilization of the silylpropylsulfonic acid.

In the second step, the membrane on the back, which will later serve as the cathode should be printed with the ink from Example 82. Even now the printed membrane again dried at a temperature of 150 ° C, whereby the solvent escapes and at the same time the silylpropylsulfonic acid is immobilized. Since the Cathode is hydrophobic, can operate when the membrane electrode assembly in the Fuel cell can easily escape the product water. This Membrane electrode unit can be in a direct methanol fuel cell or a  Reformat fuel cell to be installed.

Example 85 Manufacture of a membrane electrode assembly

To produce the electrodes, both the anode ink according to Example 80 and also the cathode ink according to Example 83 in each case on an electrically conductive Carbon paper applied. By heat treatment at a temperature of 150 ° C the solvent is removed and the proton conductive component is immobilized. These two gas diffusion electrodes are made with a proton conductive membrane pressed to a membrane electrode unit, which is then in the fuel cell can be installed.

Example 86 Manufacture of a fuel cell

To manufacture the MEA, the electrodes are first manufactured. For this, a Ceramic fleece coated with a soot / platinum mixture (40%). These electrodes are pressed onto the electrolyte membrane according to Example 77. The pressure takes place via a graphitic gas distribution plate, which is simultaneously used for the electrical Contacting serves. Pure hydrogen comes on the anode side and on the Pure oxygen on the cathode side. Both gases are over Water vapor saturator (so-called "bubbler") moistened.

Comparative example

A fuel cell was made as described in Example 86, except that as MEA a conventional Nafion®117 membrane was used. It was found, that the proton conductivity when using a Nafion membrane in a relative humidity of less than 100% dropped drastically and the Surface resistance rose sharply so that the fuel cell no longer operated  could be. On the other hand, a membrane according to the invention can also be used in a operating relative humidity, the anode side at about 10% and on the cathode side was around 5% without the function of the fuel cell was significantly affected.

Claims (68)

1. Impermeable to the reaction components of the fuel cell reaction, proton-conductive, flexible electrolyte membrane for a fuel cell, comprising a permeable composite material made of a flexible, openwork, a glass support and a porous Ceramic material, the composite with a proton conductive Material is penetrated, which is suitable for selectively protons through the membrane to lead. 2. Electrolyte membrane according to claim 1, characterized in that the proton conductive material

• a) an immobilized hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof, and optionally an oxide of aluminum, silicon, titanium, zirconium and / or phosphorus, and / or
• b) an ionic liquid which may optionally contain a Bronsted acid, and / or
• c) a Bronsted acid and an oxide of aluminum, silicon, titanium, zirconium, and / or phosphorus

includes. 3. Proton-conductive, flexible electrolyte membrane for a fuel cell, impermeable to the reaction components of the fuel cell reaction, obtainable from

• a) infiltration of a permeable composite material from a flexible, perforated support comprising a glass and a porous ceramic material with an ionic liquid in order to create a material penetrating the composite material which is suitable for selectively guiding protons through the membrane, or
• b) Infiltration of a permeable composite material from a flexible, openwork, a glass-containing carrier and a porous ceramic material with
  • 1. a mixture containing an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof; or
  • 2. a mixture containing a Bronsted acid and / or an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and a sol which comprises a precursor for oxides of aluminum, silicon, titanium, zirconium and / or phosphorus and
• c) solidifying the mixture infiltrating the composite, and optionally infiltrating the composite obtained in step (b) with an ionic liquid, in order to create a material penetrating the composite which is suitable for selectively passing protons through the membrane.

4. Electrolyte membrane according to one of claims 1 to 3, wherein the glass is aluminosilicate glass containing at least 60 wt .-% SiO ₂ and at least 10 wt .-% Al ₂ O ₃ . 5. Electrolyte membrane according to one of claims 1 to 4, characterized in that the glass of the carrier has the following composition:
64-66% by weight SiO ₂ ,
24-25% by weight Al ₂ O ₃ ,
9-12% by weight of MgO,
<0.2% by weight CaO, Na ₂ O, K ₂ O, Fe ₂ O ₃ 6. Electrolyte membrane according to one of claims 1 to 4, wherein the carrier contains fibers or filaments made of glass, which are provided with an acid-resistant coating of α-Al ₂ O ₃ , ZrO ₂ or TiO ₂ and the glass preferably has the following composition:
52-56 wt% SiO ₂
12-16 wt% Al ₂ O ₃
5-10 wt% B ₂ O ₃
16-25 wt% CaO
0-5 wt% MgO
<2 wt% Na ₂ O + K ₂ O
<1.5% by weight of TiO ₂
<1 wt% Fe ₂ O ₃ 7. Electrolyte membrane according to one of claims 2 to 6, characterized characterized that the Bronsted acid sulfuric acid, phosphoric acid, Perchloric acid, nitric acid, hydrochloric acid, sulfurous acid, phosphorous acid and esters thereof and / or a monomeric or polymeric organic acid. 8. Electrolyte membrane according to one of claims 1 to 7, characterized characterized in that the carrier comprises a fabric or fleece. 9. electrolyte membrane according to claim 8, characterized in that the Carrier fibers and / or filaments with a diameter of 1 to 150 μm, preferably 1 to 20 microns, and / or threads with a diameter of 5 to 150 microns, preferably 20 to 70 microns comprises. 10. Electrolyte membrane according to claim 8 or 9, characterized in that the carrier is a fabric with a mesh size of 5 to 500 μm, preferably 10 to 200 microns. 11. Electrolyte membrane according to one of claims 1 to 10, characterized  characterized in that the porous ceramic material has a porosity of 10% to 60%, preferably from 20% to 45%. 12. Electrolyte membrane according to one of claims 1 to 11, characterized characterized in that the porous ceramic material has pores with a medium Diameter of at least 20 nm, preferably of at least 100 nm, very particularly preferably has more than 250 nm. 13. Electrolyte membrane according to one of claims 1 to 12, the at least 80 ° C, preferably at least 120 ° C, and most preferably at at least 140 ° C, is stable. 14. Electrolyte membrane according to one of claims 1 to 13, characterized characterized in that the composite has a thickness in the range of 10 to 150 microns, preferably 10 to 80 microns, most preferably 10 to 50 microns having. 15. Electrolyte membrane according to one of claims 1 to 14, which has a bending radius of at least 100 mm, preferably at least 20 mm, whole tolerated particularly preferably of at least 5 mm. 16. Electrolyte membrane according to one of claims 1 to 15, which A room temperature and a relative humidity of 35% Conductivity of at least 2 mS / cm, preferably at least 20 mS / cm, very particularly preferably has 23 mS / cm. 17. A method for producing an electrolyte membrane according to one of claims 1 to 16, characterized in that the method comprises the following steps:

• a) infiltration of a permeable composite material from a flexible, perforated support comprising a glass and a porous ceramic material with an ionic liquid in order to create a material penetrating the composite material which is suitable for selectively guiding protons through the membrane, or
• b) Infiltration of a permeable composite material from a flexible, openwork, a glass-containing carrier and a porous ceramic material with
  • 1. a mixture containing an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof; or
  • 2. a mixture containing a Bronsted acid and / or an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and a sol which comprises a precursor for oxides of aluminum, silicon, titanium, zirconium and / or phosphorus and
  Solidification of the mixture infiltrating the composite, and optionally infiltration of the composite obtained in step (b) with an ionic liquid in order to create a material penetrating the composite which is suitable for selectively guiding protons through the membrane.

18. The method of claim 17, wherein the sol is obtainable by

• 1. (a1-1) hydrolysis of a hydrolyzable compound, preferably in a mixture of water and alcohol, to give a hydrolyzate, the hydrolyzable compound being selected from hydrolyzable alcoholates, acetates, acetylacetonates, nitrates, oxynitrates, chlorides, oxychlorides, carbonates Aluminum, silicon, titanium, zirconium, and / or phosphorus or esters, preferably methyl esters, ethyl esters and / or propyl esters of phosphoric acid or phosphoric acid,
• 2. (a1-2) peptizing the hydrolyzate to a sol.

19. The method according to claim 17 or 18, characterized in that the mixture of further proton-conducting substances, preferably titanium phosphates, titanium phosphonates, zirconium phosphates, zirconium phosphonates, iso- and heteropoly acids, preferably tungsten phosphoric acid or silicon tungstic acid, nanocrystalline and / or crystalline metal oxides, wherein Al ₂ O ₃ , ZrO ₂ , TiO ₂ or SiO ₂ powders are preferred. 20. The method according to any one of claims 17 to 19, wherein the infiltration by Printing on, pressing on, pressing in, rolling up, knife coating, spreading on, Dip, spray or pour the mixture onto the permeable fabric Composite material is made. 21. The method according to any one of claims 17 to 20, wherein the infiltration with the Mixing is carried out repeatedly and if necessary Drying step, preferably at an elevated temperature in one Range from 50 to 200 ° C between repeated infiltration. 22. The method according to any one of claims 17 to 21, wherein the infiltration of the permeable composite material takes place continuously. 23. The method according to any one of claims 17 to 22, wherein a heated Composite is infiltrated. 24. The method according to any one of claims 17 to 23, wherein the solidification by Heating to a temperature of 50 to 800 ° C, preferably 100 to 600 ° C, very particularly preferably 150 to 200 ° C. 25. The method of claim 20 or 21, wherein the heating by heated  Air, hot air, infrared radiation or microwave radiation takes place. 26. Flexible membrane electrode assembly for a fuel cell, with an electrical conductive anode and cathode layers, each on opposite Pages one for the reaction components of the fuel cell reaction impermeable, proton conductive, flexible electrolyte membrane for one Fuel cell, in particular according to one of claims 1 to 16, provided are, the electrolyte membrane is a permeable composite material from a flexible, openwork, a glass and a support comprises porous ceramic material, wherein the composite material with a proton conductive material is interspersed, which is suitable selectively protons to pass through the membrane, and wherein the anode layer and the Are porous cathode layer and each have a catalyst for the anode and Cathode reaction, a proton conductive component and optionally comprise a catalyst carrier. 27. The membrane electrode assembly according to claim 26, wherein the proton-conductive component of the anode and / or cathode layer and / or the proton-conductive material of the composite material each comprises

• a) an immobilized hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof, and optionally an oxide of aluminum, silicon, titanium, zirconium and / or phosphorus, and / or
• b) a Bronsted acid and an oxide of aluminum, silicon, titanium, zirconium, and / or phosphorus and optionally
• c) inorganic oxides, phosphates, phosphides, phosphonates, sulfates, sulfonates, vanadates, antimonates, stannates, plumbates, chromates, tungstates, molybdates, manganates, titanates, silicates, aluminosilicates and aluminates of the elements lithium, sodium, potassium, magnesium, calcium, Aluminum, silicon, titanium, zirconium, yttrium, phosphorus vanadium, tungsten, molybdenum, chromium, manganese, iron, cobalt, nickel, copper, zinc
  or cerium or a combination of these elements,

and the proton conductive material of the composite optionally comprises an ionic liquid which may contain Bronsted acid. 28. The membrane electrode assembly according to claim 27, wherein the hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof is an organosilicon compound of the general formulas
[{(RO) _y (R ² ) _z } _a Si {R ¹ -SO ₃ ^- } _a ] _x M ^{x +} (I)
or
[(RO) _y (R ² ) _z Si {R ¹ -O _b -P (O _c R ³ ) O ₂ ^- } _a ] _x M ^{x +} (II)
, where R ^{1 is} a linear or branched alkyl or alkylene group having 1 to 12 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms or a unit of the general formulas
stands,
where n, m each represents an integer from 0 to 6,
M represents H, NH ₄ or a metal,
x = 1 to 4,
y = 1 to 3, z = 0 to 2 and a = 1 to 3, with the proviso that y + z = 4 - a,
b, c = 0 or 1,
R, R ^{2 are the} same or different and stand for methyl, ethyl, propyl, butyl radicals or H.
and
R ^{3 represents} M or a methyl, ethyl, propyl or butyl radical. 29. The membrane electrode assembly according to claim 28, wherein the hydroxysilylalkyl acid sulfur or phosphorus trihydroxysilylpropylsulfonic acid, Trihydroxysilylpropylmethylphosphonic acid or dihydroxysilylpropyl is sulfondioic acid. 30. Membrane electrode unit according to one of claims 27 to 29, characterized characterized in that the hydroxysilylalkyl acid of sulfur or Phosphorus or a salt thereof with a hydrolyzed compound of Phosphorus or a hydrolyzed nitrate, oxynitrate, chloride, oxychloride, Carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal is immobilized. 31. Membrane electrode unit according to claim 30, characterized in that the hydroxysilylalkyl acid of sulfur or phosphorus or a salt of which with a hydrolyzed compound obtained from diethyl phosphite (DEP), Diethyl ethyl phosphonate (DEEP), titanium propylate, titanium ethylate, Tetraethyl orthosilicate (TEOS) or tetramethyl orthosilicate (TMOS), Zirconium nitrate, zirconium oxynitrate, zirconium propylate, zirconium acetate or Zirconium acetylacetonate or methyl phosphorate is immobilized. 32. Membrane electrode unit according to one of claims 26 to 31, characterized in that the composite permeated with a proton-conductive material additionally contains an ionic liquid which comprises a cation which is selected from the imidazolium ions, pyridinium ions, ammonium ions or phosphonium ions of the following formulas:
where R and R 'can be identical or different and stand for alkyl, olefin or aryl groups or stand for hydrogen,
and wherein the ionic liquid comprises an anion which is selected from the following ions: nitrate, sulfate, hydrogen sulfate, chloroaluminations, BF ₄ ^- , alkyl borate ions, preferably triethylhexyl borate, halogenophosphate ions, preferably PF ₆ ^- . 33. Membrane electrode unit according to one of claims 26 to 32, which in a Temperature of at least 80 ° C, preferably at least 120 ° C, and can very particularly preferably be operated at at least 140 ° C. 34. Membrane electrode unit according to one of claims 26 to 33, wherein the flexible, openwork straps include an acid-proof glass. 35. Membrane electrode unit according to one of claims 26 to 34, the one Bending radius of at least 100 mm, preferably of at least 20 mm, very particularly preferably tolerated by at least 5 mm. 36. Membrane electrode unit according to one of claims 26 to 35, wherein the proton conductive component of the anode layer and cathode layer and the proton conductive material of the electrolyte membrane is the same Have composition. 37. Membrane electrode unit according to one of claims 26 to 36, wherein the  Anode layer and the cathode layer have the same composition exhibit. 38. Membrane electrode unit according to one of claims 26 to 36, wherein the Anode layer and the cathode layer different catalysts exhibit. 39. Membrane electrode unit according to one of claims 26 to 38, wherein the Catalyst carrier in the anode layer and in the cathode layer electrically is conductive. 40. A method for producing a membrane electrode unit according to one of claims 26 to 39, the method comprising the following steps,

• A) Providing a proton-conductive, flexible electrolyte membrane for a fuel cell, which is impermeable to the reaction components of the fuel cell reaction, in particular according to one of claims 1 to 16, wherein the electrolyte membrane is a permeable composite material made of a flexible, perforated, glass-containing carrier and a porous ceramic material, wherein the composite material is permeated with a proton-conductive material which is suitable for selectively guiding protons through the membrane,
• B) Provision in each case of an agent for producing an anode layer and a cathode layer, the agent in each case comprising:
  • 1. a condensable component which gives proton conductivity after the condensation of the electrode layer,
  • 2. a catalyst which catalyzes the anode reaction or the cathode reaction, or a precursor compound of the catalyst,
  • 3. optionally a carrier and
  • 4. if necessary, a pore former,
• C) applying the agents from stage (B) to one side of the electrolyte membrane from stage (A) to form a coating,
• D) Creation of a firm bond between the coatings and the electrolyte membrane with the formation of a porous, proton-conductive anode layer or cathode layer, it being possible for the anode layer and the cathode layer to be formed simultaneously or in succession.

41. The method of claim 40, wherein the application of the agent in step (C) by printing, pressing on, pressing in, rolling up, knife coating, spreading on, Dipping, spraying or pouring takes place. 42. The method according to any one of claims 40 or 41, wherein the agent according to step (B) for producing an anode layer or a cathode layer is a suspension which is obtainable by

• 1. Preparation of a hydrosol comprising a hydroxysilylalkyl acid of sulfur or phosphorus or its salt and
  optionally a hydrolyzable compound of phosphorus that immobilizes the hydroxysilylalkyl acid of sulfur or phosphorus or its salt
  or a hydrolyzable nitrate, oxynitrate, chloride, oxychloride, carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal, preferably methyl phosphorate, diethylphosphite (DEP), diethylethylphosphonate (DEEP), titanium propylate, titanium ethylate, tetraethyl orthosilicate (TEOS) or tetraethyl orthosilicate (TEOS) or Zirconium nitrate, zirconium oxynitrate, zirconium propylate, zirconium acetate or zirconium acetylacetonate,
• 2. Dispersing the catalyst and, if appropriate, the catalyst support and pore former.

43. The method according to any one of claims 40 to 42, wherein the agent according to step (B) for producing an anode layer or a cathode layer is a suspension which is obtainable by

• 1. hydrolysis of a hydrolyzable compound to a hydrolyzate, the hydrolyzable compound being selected from a hydrolyzable compound of phosphorus or
  hydrolyzable nitrates, oxynitrates, chlorides, oxychlorides, carbonates, alcoholates, acetates, acetylacetonates of a metal or semimetal, preferably aluminum alcoholates, vanadium alcoholates, titanium propylate, titanium ethylate, zirconium nitrate, zirconium oxynitrate, zirconium propylate, zirconium acetate or
  Zirconium acetylacetonate, or
  Metal acids of aluminum, silicon, titanium, vanadium, antimony, tin, lead, chromium, tungsten, molybdenum, manganese, with tungsten phosphoric acid and silicon tungsten acid being preferred,
• 2. peptizing the hydrolyzate with an acid to give a dispersion,
• 3. Mixing the dispersion with a nanocrystalline and / or crystalline metal oxide, preferably Al ₂ O ₃ , ZrO ₂ , TiO ₂ or SiO ₂ powder,
• 4. Dispersing the catalyst and optionally the carrier and pore former.

44. The method of claim 42 or 43, wherein the means for producing a Anode layer and a cathode layer are printed in step (C) and to create a firm bond between the coatings and the electrolyte membrane to form a porous, proton-conductive Anode layer or cathode layer in step (D) to a temperature of 100 to 800 ° C, preferably 150 to 500 ° C, most preferably 180  is heated to 250 ° C. 45. The method according to claim 40 or 41, characterized by

• 1. Application of the agent for producing an anode layer or cathode layer to a support membrane, preferably made of polytretrafluoroethylene, as a coating
• 2. drying of the coating obtained under (M1),
• 3. pressing the dried coating onto the electrolyte membrane at a temperature of 100 to 800 ° C., preferably 150 to 500 ° C., very particularly preferably 180 to 250 ° C.,
• 4. Removing the support membrane, in particular by mechanical detachment, chemical dissolving, or pyrolyzing or

marked by

• 1. applying the agent for producing an anode layer or cathode layer to a support membrane, preferably made of carbon paper or an electrically conductive fleece, as a coating,
• 2. drying of the coating obtained under (N1) to produce a coated support membrane,
• 3. Pressing the coated support membrane onto the electrolyte membrane at a temperature from room temperature to 800 ° C., preferably 150 to 500 ° C., very particularly preferably 180 to 250 ° C.

46. The method according to any one of claims 40 or 41, wherein in step (B) in each case providing an agent for producing an anode layer and a cathode layer, the agent each comprises:

• 1. a condensable component which gives proton conductivity after the condensation of the electrode layer and
• 2. a catalyst metal salt, preferably hexachloroplatinic acid,

after the application of the agents by step (C), the catalyst metal salt is reduced to a catalyst which catalyzes the anode reaction or the cathode reaction,
in step (D) an open-pore gas diffusion electrode, preferably an open-pore carbon paper, is pressed onto the catalyst or is glued to the catalyst with an electrically conductive adhesive. 47. The method according to any one of claims 40 to 46, wherein the application of the Repeated by means of producing an anode layer or cathode layer is carried out and optionally a drying step, preferably at an elevated temperature in a range of 100 to 200 ° C, between the repeated application is carried out. 48. The method according to any one of claims 40 to 47, wherein the application of the Means for producing an anode layer or cathode layer on one of a first roll of unrolled flexible electrolyte membrane or flexible Support membrane is made. 49. The method according to any one of claims 40 to 48, wherein the application of the Means for producing an anode layer or cathode layer done continuously. 50. The method according to any one of claims 40 to 49, wherein the application of the Means for producing an anode layer or cathode layer on a heated electrolyte or support membrane. 51. The method according to any one of claims 40 to 50, wherein in step (D) for Creation of a firm bond between the coatings and the Electrolyte membrane to a temperature of 100 to 800 ° C, preferably 150 is heated to 500 ° C, very particularly preferably 180 to 250 ° C. 52. The method according to claim 51, wherein by means of heated air, hot air,  Infrared radiation or microwave radiation is heated. 53. Medium comprising:

• 1. a condensable component which gives proton conductivity to a fuel cell after condensation of an anode layer or a cathode layer of a membrane electrode unit,
• 2. a catalyst which catalyzes the anode reaction or the cathode reaction in a fuel cell, or a precursor compound of the catalyst,
• 3. optionally a catalyst support and
• 4. optionally a pore former, and
• 5. optionally additives to improve foam behavior, viscosity and adhesion.

54. A composition according to claim 53, wherein the condensable component which gives proton conductivity to the anode layer or the cathode layer after the condensation is selected from

• A) hydrolyzable compound of phosphorus or hydrolyzable nitrates, oxynitrates, chlorides, oxychlorides, carbonates, alcoholates, acetates, acetylacetonates of a metal or semimetal, preferably aluminum alcoholates, vanadium alcoholates, titanium propylate, titanium ethylate, zirconium nitrate, zirconium oxynitate or zirconium propyl acetate
  Metal acids of aluminum, titanium, vanadium, antimony, tin, lead, chromium, tungsten, molybdenum, manganese, with tungsten phosphoric acid being preferred,
  and or
• B) an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and optionally a hydrolysable compound of the phosphorus or a hydrolyzable nitrate, oxynitrate, chloride, oxychloride, carbonate, alcoholate, acetate, acetylacetonate one of the hydroxysilylalkyl acid of sulfur or phosphorus or its salt Metal or semimetal, preferably diethylphosphonate (DEP), diethylethylphosphonate (DEEP), phosphoric acid methyl ester, titanium propylate, titanium ethylate, tetraethylorthosilicate (TEOS) or tetramethylorthosilicate (TMOS), zirconium nitrate, zirconium oxynitrate, zirconium propyl acetate, zirconium propyl acetate.

55. Agent according to claim 53 or 54, in which the catalyst or Precursor compound of the catalyst is a platinum metal or an alloy of Platinum metals and optionally a cocatalyst, wherein the Cocatalyst a transition metal complex of phthalocyanine or substituted phthalocyanines. 56. Agent according to claim 55, in which the catalyst or the precursor compound of the catalyst comprises platinum, palladium and / or ruthenium and optionally the transition metal complex comprises nickel and / or cobalt. 57. Agent according to one of claims 53 to 56, wherein the pore former organic and / or inorganic substance that is at a temperature decomposed between 50 and 600 ° C and preferably between 100 and 250 ° C. 58. Agent according to claim 57, in which the inorganic pore former Is ammonium carbonate or ammonium bicarbonate. 59. Agent according to one of claims 53 to 54, wherein the catalyst support is electrically conductive and preferably made of carbon black, graphite, carbon, carbon, Activated carbon or metal oxides.   60. Use of an electrolyte membrane according to one of claims 1 to 16 in a fuel cell. 61. Use according to claim 61, wherein the fuel cell is a direct methanol fuel cell or a reformate fuel cell. 62. Use of an electrolyte membrane according to one of claims 1 to 16 for Manufacture of a membrane electrode assembly, a fuel cell, or one Fuel cell stacks. 63. Use of a membrane electrode assembly according to one of claims 26 to 39 in a fuel cell. 64. Use according to claim 63, wherein the fuel cell is a direct methanol fuel cell or a reformate fuel cell. 65. Fuel cell with an electrolyte membrane according to one of claims 1 to 16th 66. Fuel cell with a membrane electrode unit according to one of the Claims 26 to 39. 67. Mobile or stationary system with a membrane electrode assembly, one Fuel cell or a fuel cell stack containing one Electrolyte membrane according to one of claims 1 to 16 or one Membrane electrode unit according to one of claims 26 to 39. 68. Mobile or stationary system according to claim 67, which is a vehicle or a Home energy system is.