DE10205850A1 - Flexible electrolyte membrane based on a glass fabric, process for its production and the use thereof - Google Patents

Abstract

The invention relates to a proton-conducting membrane, a process for its production and its use. This proton-conductive, flexible electrolyte membrane for a fuel cell, which is impermeable to the reaction components of the fuel cell reaction, comprises a permeable, flexible, perforated support comprising a glass, the support being permeated with a gel which is suitable for selectively guiding protons through the membrane. DOLLAR A The membrane according to the invention represents a new class of solid proton-conducting membranes. The basis is a porous and flexible support made of glass. This is infiltrated with a proton-conducting material, then the membrane is dried and the proton-conducting material is solidified into a gel, so that in the end an impermeable, proton-conducting membrane is obtained. The electrolyte membrane remains flexible and can easily be used as a membrane in a fuel cell.

Description

The present invention relates to special proton-conductive, flexible electrolyte membranes in particular for a fuel cell, a method for producing it Electrolyte membranes and a flexible membrane electrode assembly for a fuel cell, the one comprises electrolyte membrane according to the invention. The present invention further relates to special intermediates in the manufacture of the membrane electrode assembly and special Uses of the electrolyte membrane and membrane electrode assembly.

Fuel cells contain electrolyte membranes, on the one hand, the proton exchange ensure between the half-cell reactions and on the other hand prevent it from there is a short circuit between the half-cell reactions.

So-called membrane electrode units are conventionally used in fuel cells (MEAs) used, which consist of an ion-conducting electrolyte membrane and the applied, if necessary, catalytically active electrodes (anode and cathode).

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

However, organic polymers have the disadvantage that the conductivity depends on the water content of the Depends on membranes. Therefore, these membranes must be used in the Fuel cells are swollen in water and although water is constantly being formed on the cathode, additional water must be added from the outside during operation of the membrane in order to prevent drying out or a decrease in proton conductivity. typically, must have organic polymer membrane in a fuel cell both anode and be operated on the cathode side in an atmosphere saturated with water vapor.

At elevated operating temperatures, electrolyte membranes can be made from organic polymers not be used because the water content in at temperatures above about 100 ° C the membrane can no longer be guaranteed at atmospheric pressure. The use of such membranes in a reformate or direct methanol fuel cell is therefore in the Usually not possible. In addition, the polymer membranes are used in a Direct methanol fuel cells show too high a permeability for methanol. By the So-called cross-over of methanol on the cathode side can only be slight Realize power densities in the direct methanol fuel cell.

Therefore, conventional organic polymer membranes for use in a reformate or direct methanol fuel cell not in practice despite the high proton conductivity useful.

Inorganic proton conductors are e.g. B. from "Proton Conductors", P. Colomban, Cambridge University Press, 1992 known. For the purposes of a fuel cell, however, 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 can also not be in the form of Produce thin membrane films that provide a low overall resistance Cell are required. Low surface resistances and high power densities Fuel cells for technical applications in automobile construction are made with the known materials therefore not possible.

WO 99/62620 proposes an ion-conducting, permeable composite material as well its use as an electrolyte membrane of an MEA in a fuel cell. The Electrolyte membrane from the prior art consists of a metal network, which with a porous ceramic material is coated on a proton conductive material was applied. This electrolyte membrane has an organic one Nafion membrane superior proton conductivity at temperatures above 80 ° C. The booth However, the technology does not contain an embodiment of a fuel cell in which one 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 terms of the manufacturing process that is required to provide such MEAs. Due to these disadvantages, the Known WO 99/62620 unsuitable for use in a fuel cell in practice. It has been shown that the known electrolyte membranes do indeed increase Temperatures have good proton conductivity, but on the other hand below practical application conditions occur in a fuel cell short circuits that the Make electrolyte membranes unusable. Furthermore, those known from WO 99/62620 Electrolyte membranes regarding the adhesion of the ceramic material to the metal support problematic, so that with long standing times with a detachment of the ceramic layer from Metal network must be expected.

Against this background, the applicant has developed membranes which have no metal support (DE 100 61 920, DE 101 15 927, DE 101 15 928). Although these materials are excellent proton-conducting membranes (hereinafter referred to as cPEM), in practice it has been shown that the conductivity that can be achieved with these materials and therefore also the power density of the fuel cell is not sufficient. The reason for this is that the microfiltration membranes used as the base membrane (MF membranes, cf. WO 99/15262), based on a permeable composite material, have ceramics which have an insufficient porosity of max. 45% by volume, but typically only 30-35% by volume, and also have an uneven pore structure on the inside. As FIGS. 1a and 2a show, only the area of the MF membrane that is free of ceramic or glass fabric can be filled with electrolyte. FIGS. 2a describes the real case of the fabric used better than 1a. Each thread consists of several filaments. When infiltrating such a membrane, it is now very difficult to get the sol through the comparatively small-pore ceramic layer, so that the large spaces between the glass filaments are completely filled. A large proportion of dead volume not filled with electrolyte is inevitable. This problem cannot be solved by bilateral infiltration either.

Due to these effects, the degree of filling with the electrolyte is too low by one Proton conductivity of the membrane to ensure use in fuel cells enables economically sensible.

• a) eine hohe Protonenleitfähigkeit bei deutlich reduzierter Luftfeuchtigkeit im Vergleich zu Polymermembranen aufweist,
• b) eine höhere Protonenleitfähigkeit als Membranen zeigen, die auf Verbundwerkstoffen basieren, die wiederum poröse Keramiken aufweisen,
• c) einen geringen Gesamtwiderstand einer Membranelektrodeneinheit ermöglicht,
• d) mechanische Eigenschaften, wie Zugfestigkeit und Flexibilität, aufweist, die für einen Einsatz unter extremen Bedingungen, wie sie beim Betrieb eines Fahrzeugs auftreten, geeignet sind,
• e) erhöhte Betriebstemperaturen von mehr als 80°C toleriert,
• f) Kurzschlüsse und cross-over-Probleme vermeidet, und
• g) einfach hergestellt werden kann.

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

• a) has a high proton conductivity with significantly reduced air humidity compared to polymer membranes,
• b) show a higher proton conductivity than membranes based on composite materials, which in turn have porous ceramics,
• c) enables a low total resistance of a membrane electrode unit,
• d) has mechanical properties, such as tensile strength and flexibility, which are suitable for use under extreme conditions, such as occur during the operation of a vehicle,
• e) tolerated increased operating temperatures of more than 80 ° C,
• f) avoids short circuits and cross-over problems, and
• g) can be easily manufactured.

Surprisingly, it was found that electrolyte membranes perform the above-mentioned tasks can be easily manufactured in which instead of the used MF membranes directly glass supports such. B. glass fabric or nonwovens, used with the Electrolytes are infiltrated. Because the porosity of these supports, fabrics or fleeces is essential the achievable conductivity is correspondingly higher than that of the MF membrane. The Porosity lies e.g. T. up to 70%, typically 55-60 vol.%, Is about twice as much high as with the known MF membranes. It is important that the carrier is not easy in z. B. mineral acids can be soaked, but that the electrolyte immobilized in the form of a gel or glass must end up in the tissue.

The present invention therefore relates to one for the reaction components Fuel cell reaction impermeable, proton conductive, flexible electrolyte membrane for a fuel cell comprising a flexible, openwork, a glass Carrier, the carrier being permeated with a proton conductive gel that is suitable selectively direct protons through the membrane.

• a) Infiltration eines flexiblen, durchbrochenen, ein Glas umfassenden Träger mit
  • 1. einer Mischung, enthaltend eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder einem Salz davon; oder
  • 2. einer Mischung, enthaltend eine Brönstedsäure und/oder eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder ein Salz davon sowie ein Sol, das eine Vorstufe für Oxide von Aluminium, Silizium, Titan, Zirkonium, und/oder Phosphor als Netzwerkbildner umfasst und
• b) Verfestigung der den Träger infiltrierenden Mischung, um ein den Träger durchsetzendes Gel zu schaffen, das geeignet ist selektiv Protonen durch die Membran zu leiten, erhalten wird.

The present invention also relates to a proton-conductive, flexible electrolyte membrane for a fuel cell which is impermeable to the reaction components of a fuel cell reaction and which is characterized by

• a) Infiltration of a flexible, openwork, glass-enclosed carrier 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 as a network former and
• b) Solidification of the mixture infiltrating the carrier in order to create a gel which penetrates the carrier and is suitable for selectively passing protons through the membrane.

• a) Infiltration eines flexiblen, durchbrochenen, ein Glas umfassenden Träger mit
  • 1. einer Mischung, enthaltend eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder einem Salz davon; oder
  • 2. einer Mischung, enthaltend eine Brönstedsäure und/oder eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder ein Salz davon sowie ein Sol, das eine Vorstufe für Oxide von Aluminium, Silizium, Titan, Zirkonium, und/oder Phosphor als Netzwerkbildner umfasst und
• b) Verfestigung der den Träger infiltrierenden Mischung, um ein den Träger durchsetzendes Gel zu schaffen, das geeignet ist selektiv Protonen durch die Membran zu leiten.

The present invention also relates to a method for producing an electrolyte membrane according to the invention, which is characterized in that the method comprises the following steps:

• a) Infiltration of a flexible, openwork, glass-enclosed carrier 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 as a network former and
• b) solidification of the mixture infiltrating the carrier in order to create a gel which penetrates the carrier and is suitable for selectively guiding protons through the membrane.

At the same time, the subject of the present invention is a flexible one Membrane electrode unit for a fuel cell, with an electrically conductive anode and Cathode layer, each on opposite sides of a particular one invention for the reaction components of the fuel cell reaction impermeable, proton conductive, flexible electrolyte membrane provided for a fuel cell are, the electrolyte membrane is a flexible, openwork, enclosing a glass Carrier comprises, wherein the carrier is permeated with a proton-conductive gel, the is capable of selectively guiding protons through the membrane, and wherein the anode layer and the cathode layer are porous and each have a catalyst for the anode and Cathode reaction, a proton conductive component and optionally one Include catalyst support.

• A) Bereitstellung einer insbesondere erfindungsgemäßen für die Reaktionskomponenten der Brennstoffzellenreaktion undurchlässigen, protonenleitfähigen, flexiblen Elektrolytmembran für eine Brennstoffzelle, wobei die Elektrolytmembran einen stoffdurchlässigen, flexiblen, durchbrochenen, ein Glas umfassenden Träger umfasst, wobei der Träger mit einem protonenleitfähigen Gel durchsetzt ist, das geeignet ist selektiv Protonen durch die Membran zu leiten,
• B) Bereitstellung jeweils eines Mittels zur Herstellung einer Anodenschicht und einer Kathodenschicht, wobei das Mittel jeweils umfasst:
  • 1. eine kondensierbare Komponente, die nach der Kondensation der Elektrodenschicht Protonenleitfähigkeit verleiht,
  • 2. einen Katalysator, der die Anodenreaktion bzw. die Kathoden-reaktion katalysiert, oder eine Vorstufenverbindung des Katalysators,
  • 3. gegebenenfalls einen Träger und
  • 4. gegebenenfalls einen Porenbildner,
• C) Aufbringen der Mittel aus Stufe (B) auf jeweils eine Seite der Elektrolytmembran zur Bildung einer Beschichtung,
• D) Schaffung eines festen Verbundes zwischen den Beschichtungen und der Elektrolytmembran unter Ausbildung einer porösen, protonenleitfähigen Anodenschicht oder Kathodenschicht, wobei die Ausbildung der Anodenschicht und der Kathodenschicht gleichzeitig oder nacheinander erfolgen kann.

The present invention also relates to a method for producing a membrane electrode unit according to the invention, the method comprising the following steps:

• A) Provision of a proton-conductive, flexible electrolyte membrane, in particular for the reaction components of the fuel cell reaction, which is impermeable to the fuel cell reaction, for a fuel cell, the electrolyte membrane comprising a permeable, flexible, openwork, glass-containing carrier, the carrier being permeated with a proton-conductive gel which is suitable selectively direct 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 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.

• 1. eine kondensierbare Komponente, die nach der Kondensation einer Anodenschicht oder einer Kathodenschicht einer Membranelektrodeneinheit einer Brennstoffzelle Protonenleitfähigkeit verleiht,
• 2. einen Katalysator, der die Anodenreaktion oder die Kathodenreaktion in einer Brennstoffzelle katalysiert, oder eine Vorläuferverbindung des Katalysators,
• 3. gegebenenfalls einen Katalysatorträger und
• 4. gegebenenfalls einen Porenbildner, und
• 5. gegebenenfalls Additive zur Verbesserung von Schaumverhalten, Viskosität und Haftung.

The present invention also relates to an agent comprising:

• 1. a condensable component which, after the condensation of an anode layer or a cathode layer of a membrane electrode assembly, imparts proton conductivity to a fuel cell,
• 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.

At the same time, the present invention relates to the use of a electrolyte membrane according to the invention in a fuel cell or for the production of a Membrane electrode unit, a fuel cell, or a fuel cell stack.

The present invention also relates to the use of a device according to the invention Membrane electrode unit in a fuel cell and fuel cells with one electrolyte membranes according to the invention or according to the invention Membrane electrode assemblies.

The membranes according to the invention have the advantage that they are high Proton conductivity with significantly reduced air humidity compared to conventional ones Have polymer membranes. Furthermore, electrolyte membranes according to the invention have higher proton conductivity than membranes based on composite materials, which have porous ceramics. In addition, enable according to the invention Electrolyte membranes manufacture membrane electrode assemblies that have a low total resistance have good mechanical properties such as tensile and compressive strength as well Flexibility, which is suitable for use under extreme conditions, such as during operation of a vehicle, are suitable, increased operating temperatures of more than 80 ° C tolerate and avoid short circuits and cross-over problems.

With the method according to the invention, membranes are obtained which also have the advantage have that they can be extremely flexible and a bending radius of a few mm or more can have below. This is another advantage compared to the cPEMs based of MF membranes, which are quite brittle and due to this fact easy to Sealing or fail catastrophically when operating in the fuel cell. The Membrane based on glass fabrics according to the invention show practically the same Elasticity but also the same strength as the glass fabric itself.

The electrolyte membrane of the present invention also has the advantage that it does not need to be swollen in water to achieve a useful conductivity. It is therefore much easier to combine the electrodes and the electrolyte membrane To combine membrane electrode assembly. In particular, there is no need for one to provide the swollen membrane with an electrode layer, as in the case of a Nafion membrane is necessary to prevent the electrode layer from swelling tears. The choice of the special carrier also ensures firm adhesion of the porous one Ceramic material on the carrier possible. This enables a stable MEA to be produced that can withstand high mechanical loads. Due to the good stability and The electrolyte membranes according to the invention can be conductive in a reformate or Direct methanol fuel cells are used, the long service life as well as long Have power densities even at low water partial pressures and high temperatures.

It is also possible to maintain the water balance of the new membrane electrode units through the Control the hydrophobicity / hydrophilicity of the membrane and electrodes. By The targeted creation of nanopores in the membrane can also have the effect of Use capillary condensation. A flooding of the electrodes by product water or Drying out of the membrane at a higher operating temperature or current density can thus be avoided. Through the use of diffusion barriers, i.e. proton conductive Coatings that are not soluble in water and methanol can also do that Prevent the phenomenon of electrolyte bleeding. The diffusion barriers themselves are Subject of a property right applied for in parallel.

The membranes according to the invention are gas-tight or impermeable to Reaction components in a fuel cell, such as. B. hydrogen, oxygen, air and / or Methanol. Under gas-tight or impermeable to the reaction components in the sense of The present invention understood that less than 50 liters of hydrogen and less than 25 liters of oxygen per day, bar and square meter passes through and the permeability of the membrane for methanol is significantly lower than in commercially available Nafion membranes, which are usually also referred to as impermeable become.

The membranes according to the invention, the method according to the invention for producing them Membrane as well as the various uses or articles that this membrane are described below, without the invention being based on this Types of execution should be limited.

The membranes according to the invention are characterized in that they are suitable for Reaction components of the fuel cell reaction impermeable, proton conductive, are flexible electrolyte membranes for a fuel cell that have a flexible, openwork carrier comprising a glass, the carrier containing a proton-conductive gel which is capable of selectively guiding protons through the membrane. The proton-conducting gel has a plastic and / or elastic deformability.

• a) eine immobilisierte Hydroxysilylalkylsäure von Schwefel oder Phosphor sowie gegebenenfalls ein Oxid von Aluminium, Silizium, Titan, Zirkonium und/oder Phosphor als Netzwerkbildner, und/oder
• b) eine Brönstedsäure und ein Oxid von Aluminium, Silizium, Titan, Zirkonium, und/oder Phosphor als Netzwerkbildner.

The proton conductive gel preferably comprises

• a) an immobilized hydroxysilylalkyl acid of sulfur or phosphorus and optionally an oxide of aluminum, silicon, titanium, zirconium and / or phosphorus as a network former, and / or
• b) a Bronsted acid and an oxide of aluminum, silicon, titanium, zirconium, and / or phosphorus as a network former.

• a) Infiltration eines flexiblen, durchbrochenen, ein Glas umfassenden Träger mit
  • 1. einer Mischung, enthaltend eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder einem Salz davon; oder
  • 2. einer Mischung, enthaltend eine Brönstedsäure und/oder eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder ein Salz davon sowie ein Sol, das eine Vorstufe für Oxide von Aluminium, Silizium, Titan, Zirkonium, und/oder Phosphor umfasst und
• b) Verfestigung der den Träger infiltrierenden Mischung, um ein den Träger durchsetzendes Gel zu schaffen, das geeignet ist selektiv Protonen durch die Membran zu leiten, erhältlich.

The proton-conductive, flexible electrolyte membranes for a fuel cell, which are impermeable to the reaction components of the fuel cell reaction, are e.g. B. by

• a) Infiltration of a flexible, openwork, glass-enclosed carrier 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
• b) Solidification of the mixture infiltrating the carrier in order to create a gel which penetrates the carrier and is suitable for selectively passing protons through the membrane.

The gel-like structure is ensured by cross-linking the components, the Crosslinking by poly- or oligomerization, especially the hydroxysilylalkyl acids and / or by using the oxides mentioned as network formers.

The proton-conducting gel can be an organic and / or an inorganic material. The proton-conducting gel can only have material that has proton-conducting properties has or not in addition to the material with proton-conducting properties have proton-conducting material which, for. B. have support functions or form networks can.

The proton-conductive gel of an electrolyte membrane according to the invention preferably comprises a Bronsted acid, an immobilized hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof. These components impart proton conductivity to the electrolyte membrane. If appropriate, the proton-conductive gel can contain an oxide of aluminum, silicon, titanium, zirconium and / or phosphorus as a network former. Such an oxide is essential when using Bronsted acid. In the event that an immobilized hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof is present, the additional oxide can be dispensed with, since an SiO ₂ network can form in which the acidic groups via the three remaining OH groups of the Hydroxysilylalkyl acid are condensed. The network can also contain other network-forming oxides such as SiO ₂ , Al ₂ O ₃ , ZrO ₂ , or TiO ₂ .

The Bronsted acid can e.g. B. sulfuric acid, phosphoric acid, perchloric acid, nitric acid, Hydrochloric acid, sulfurous acid, phosphorous acid and esters thereof and / or one be monomeric or polymeric organic acid.

As the hydroxysilylalkyl acid of sulfur or phosphorus, the gel in the electrolyte membrane according to the invention preferably has 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)

on, 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


or

stands,
in which
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 or H and
R ^{3 represents} M or a methyl, ethyl, propyl or butyl radical.

The gel in the electrolyte membrane according to the invention particularly preferably has Hydroxysilylalkyl acid of sulfur or phosphorus trihydroxysilylpropylsulfonic acid, Trihydroxysilylpropylmethylphosphonic acid or dihydroxysilylpropylsulfonedioic acid.

The hydroxysilylalkyl acid of sulfur or phosphorus is preferred with a hydrolyzed compound of phosphorus or a hydrolyzed nitrate, oxynitrate, chloride, Oxychloride, carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal or 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, zirconium acetylacetonate, methyl phosphorate or with precipitated silica immobilized.

It can be advantageous if the gel has ceramic particles of at least one oxide selected from the series Al ₂ O ₃ , SiO ₂ , ZrO ₂ or TiO ₂ . The proportion of ceramic particles which make no contribution to proton conductivity in the gel is preferably less than 50 percent by volume, particularly preferably less than 30 percent by volume and very particularly preferably less than 10 percent by volume. It can be advantageous if the ceramic particles have one or more particle size fractions with particle sizes in the range from 10 to 100 nm, from 100 to 1000 nm and / or from 1 to 5 μm. Coarser particle fractions with particle sizes of 0.1 to 5 μm, such as B. Al ₂ O ₃ (AlCoA CT3000) or ZrO ₂ (Tosoh TZ3Y), finer particle or agglomerate sizes from 50 nm to 500 nm, such as. B. Aerosil 200, Aerosil Ox50 or Aerosil VP 25 (each Degussa AG), or very fine-scaled particles, the z. B. be used directly as a suspension, such as. B. Levasil200E (Bayer AG). The concentration of protons is reduced by the additional proportion of powder, but the membrane is so much easier to manufacture without cracks.

In contrast to the proton-conducting microfiltration membranes, the membranes according to the invention have a significantly higher proportion of material with proton-conducting properties, since the ceramic material proportion is completely or at least partially dispensed with. This is shown schematically in FIGS. 1 and 2. In the realistic Fig. 2b can be clearly seen that it is easily possible, glass fabric completely with particle-containing sols, that is to infiltrate without dead volumes, as in the infiltration of MF membranes (see. Fig. 2a).

It may be advantageous if the gel has other proton-conducting substances. Preferred proton-conducting substances are e.g. For example, selected from the titanium phosphates, Titanphosphonaten, Titansulfoarylphosphonaten, zirconium phosphates, Zirkoniumphosphonaten, Zirkoniumsulfoarylphosphonaten, iso- and heteropoly acids, preferably tungstophosphoric acid or silicotungstic acid, or nano-crystalline metal oxides and Al ₂ O ₃ - ZrO ₂ -, TiO ₂ - or SiO ₂ powder are preferred. These can again (if necessary) form the proton-conducting gel in combination with the network formers mentioned. In the case of the phosphates or phosphonates, the Zr-OP or Ti-OP groups are immobilized via a ZrO ₂ or TiO ₂ network.

The electrolyte membrane according to the invention preferably has a volume ratio of gel to wearers of at least 30 to 70. The volume ratio of gel to is preferably Carriers from 35 to 65 to 90 to 10, particularly preferably from 40 to 60 to 80 to 20 and whole particularly preferably from 50 to 50 to 70 to 30.

The carrier comprising glass preferably has glass, in particular ECR, S or (with restriction) also E glass. In addition to the glass, the carrier can also have other components. In particular, the glass substrate as components oxidic coatings, such as. B. Al ₂ O ₃ , SiO ₂ , TiO ₂ or ZrO ₂ coatings of the glass. The oxidic coatings are particularly preferred for types of glass that have low acid stability, such as. B. E-glass. The weight ratio of oxidic coating to glass in the carrier is preferably less than 15 to 85, preferably less than 10 to 90 and very particularly preferably less than 5 to 95. In order to achieve good protection of the glass fabric, very dense oxide films must be formed. This can be achieved by using particle-free, polymeric brine based on the corresponding hydrolyzable compounds of Al, Zr, Ti or Si. These thin ceramic films protect the individual filaments.

The glass of the carrier is preferably an aluminosilicate glass, a silicate glass or a Borosilicate glass, each of which may contain other elements. Another element is Magnesium particularly preferred. The alkali metal content should be as low as possible, in order not to endanger the stability of the glass under the operating conditions.

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 of Al ₂ O _{3 is present} in the glass, the softening point of the glass may be too low and the industrial manufacture of the membranes according to the invention may therefore become very difficult.

Other elements that are present in an aluminosilicate glass, silicate glass or borosilicate glass are alkali metals, such as lithium, sodium, potassium, rubidium, or cesium, Alkaline earth metals, such as magnesium, calcium, strontium or barium as well as 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:
from 64 to 66% by weight SiO ₂ ,
from 24 to 25% by weight of Al ₂ O ₃ ,
from 9 to 12% by weight of MgO and
less than 0.2% by weight of CaO, Na ₂ O, K ₂ O and / or Fe ₂ O ₃ .

The carrier must be used both in the course of the production of the electrolyte membrane and under the Operating conditions in a fuel cell must be stable. Therefore, the glass is for the wearer preferably stable to protons which are passed through the membrane and compared to the proton-conducting material (gel) with which the membrane is penetrated. It is therefore particularly preferred if the glass does not contain any acid-leachable cations contains. On the other hand, leachable cations can be present in the glass if the stability of the Carrier does not suffer if cations are replaced by protons, for example if that Glass is suitable to form a gel layer on the surface, which protects the glass support from one protects further attack of acid.

It is also possible to use a glass, quartz or quartz glass which has a stability under operating conditions which is not sufficient for practical use (in particular an insufficient acid stability). 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 e.g. B. SiO ₂ , 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 also available as material:
from 52 to 56% by weight of SiO ₂ ,
from 12 to 16% by weight of Al ₂ O ₃ ,
from 5 to 10% by weight of B ₂ O ₃ ,
from 16 to 25% by weight CaO,
from 0 to 5% by weight of MgO,
less than 2% by weight Na ₂ O + K ₂ O,
less than 1.5% by weight of TiO ₂ and
less than 1% by weight of Fe ₂ O ₃ .

The glass from which the support is made preferably has a softening point of greater than 700 ° C, particularly preferably greater than 800 and very particularly preferably greater than 1000 ° C. Preferred carriers have glasses whose weight loss in 10% HCl after 24 h is preferably less than 4% by weight and after 168 h less than 5.5% by weight.

The flexible, perforated support comprising a glass can further comprise components which are selected from ceramics, minerals, amorphous non-conductive substances, Natural products, or at least a combination of these materials, provided that these materials the usefulness of the electrolyte membrane according to the invention among the Operating conditions in a fuel cell and do not interfere with the above made restrictions on the weight proportions of these components on the carrier. The carrier preferably comprises a woven or non-woven fabric. The carrier preferably comprises Fibers and / or filaments with a diameter of 1 to 150 microns, preferably 1 to 20 microns, and / or threads with a diameter of 5 to 150 microns, preferably 20 to 70 microns.

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

The electrolyte membrane according to the invention is preferably at least 80 ° C. preferably at least 100 ° C, and very particularly preferably at least 120 ° C, stable.

The electrolyte membrane preferably has a thickness in the range from 10 to 150 μm, preferably 10 to 80 μm, very particularly preferably 10 to 50 μm. The invention Electrolyte membrane preferably tolerates a bending radius of down to 5000 mm, preferably 100 mm, in particular from down to 50 mm, preferably 20 mm and entirely particularly preferably from down to 5 mm.

The electrolyte membrane according to the invention exhibits at room temperature and at a relative Air humidity of at most 40%, preferably a conductivity of at least 5 mS / cm, preferably at least 20 mS / cm, very particularly preferably at least 50 mS / cm.

It can be advantageous if the membrane according to the invention has an additional coating on the side surfaces which serves as a diffusion barrier and prevents leaching of an electrolyte from the electrolyte membrane. This coating has a water- and methanol-insoluble proton-conducting material. As a material for the diffusion barrier, the membranes according to the invention can in particular be the polymeric proton conductors known from the specialist literature, such as B. Nafion®, sulfonated or phosphonated polyphenyl sulfones, polyimides, polyoxazoles, polytriazoles, polybenzimidazoles, polyether ether ketones (PEEK), polyether ketones (PEK), etc. or inorganic proton conductors, such as, for. B. immobilized sulfonic or phosphonic acid (z. B. hydroxysilylalkyl acids), zirconium or titanium phosphates or phosphonates. These inorganic proton conductors can also contain other oxides, e.g. B. of Al, Zr, Ti or Si, included as a network former. The organic proton-conducting polymers can be applied either as pure materials or in the form of inorganic-organic composite materials. Such composite materials can e.g. B. Solidified solutions from Nafion with precipitated silica (Levasil®), tetraethoxysilane (Dynasilan A®, TEOS) or with sols based on Al ₂ O ₃ , SiO ₂ , TiO ₂ or ZrO ₂ . The combination of organic proton conductors with immobilized inorganic sulfonic and phosphonic acids is also possible. The use of composite materials has the advantage that the adhesive strength of the protective layer on the membrane is better than that of the pure (hydrophobic) proton-conducting polymer.

All materials can also be used in the range of polymeric proton conductors, in particular are used, which do not form or only very poorly dense, thin films and thus as Eliminate self-supporting membranes.

The presence of a diffusion barrier can prevent the membrane from bleeding out and the mechanical stability can be improved. This results in a higher one Long-term performance compared to membranes that show electrolyte bleeding.

To avoid performance losses that can occur because of the diffusion barrier has lower proton conductivity than the membrane according to the invention without Diffusion barrier, the diffusion barrier is made as thin as possible. Preferably points the diffusion barrier has a thickness of less than 5 μm, preferably from 10 to 1000 nm and entirely particularly preferably from 100 to 500 nm. Due to the very thin design of the Diffusion barrier, only affects the lower conductivity of the diffusion barrier the proton conductivity of the actual membrane is insignificant.

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

• a) Infiltration eines stoffdurchlässigen, flexiblen, durchbrochenen, ein Glas umfassenden Trägers mit
  • 1. einer Mischung, enthaltend eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder einem Salz davon; oder
  • 2. einer Mischung, enthaltend eine Brönstedsäure und/oder eine immobilisierbare Hydroxysilylalkylsäure von Schwefel oder Phosphor oder ein Salz davon sowie ein Sol, das eine Vorstufe für Oxide von Aluminium, Silizium, Titan, Zirkonium, und/oder Phosphor als Netzwerkbildner umfasst, und
• b) Verfestigung der in den Träger infiltrierten Mischung, um ein den Träger durchsetzendes Gel zu schaffen, das geeignet ist selektiv Protonen durch die Membran zu leiten.

An electrolyte membrane of the present invention is e.g. B. obtainable by the method according to the invention for producing an electrolyte membrane, which, starting from the permeable support, comprises in particular the following steps:

• a) Infiltration of a permeable, flexible, openwork, a glass-containing carrier 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 as a network former, and
• b) Solidification of the mixture infiltrated in the carrier in order to create a gel which penetrates the carrier and is suitable for selectively guiding protons through the membrane.

The gel formation is due to condensation and / or polymerization or Oligomerization reactions that take place during the solidification, in particular free OH- Condense groups together. The structure of the gel depends on the degree of condensation, which can be controlled via the temperature and the duration of the heat treatment.

As available in the mixture Bronsted acid z. B. 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 can be used. Preferred organic acids are immobilizable sulfonic and / or phosphonic acids. As the oxides of Al, Zr, Ti and Si can be used as additional network formers.

Organosilicon compounds of the general formulas are preferably used as the hydroxysilylalkyl acid of sulfur or phosphorus in the mixture

[{(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)

used, 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,
in which
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 or H and
R ^{3 represents} M or a methyl, ethyl, propyl or butyl radical.

Particularly preferred are hydroxysilylalkyl acid of sulfur or phosphorus Trihydroxysilylpropylsulfonic acid, trihydroxysilylpropylmethylphosphonic acid or Dihydroxysilylpropylsulfondisäure used in the mixture.

The hydroxysilylalkyl acid of sulfur or phosphorus is preferred with a hydrolyzed compound of phosphorus or a hydrolyzed nitrate, oxynitrate, chloride, Oxychloride, carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal or 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, zirconium acetylacetonate, phosphoric acid methyl ester or with precipitated silica immobilized.

It can be advantageous if the mixture contains further proton-conducting substances selected from the group of iso- or heteropolyacids, such as, for example, tungsten phosphoric acid or silicon tungstic acid, zeolites, mordenites, aluminosilicates, β-aluminum oxides, zirconium, titanium or cerium phosphates or phosphonates sulfoarylphosphonates, antimonic acids, phosphorus oxides, sulfuric acid, perchloric acid or their salts and / or crystalline metal oxides, preference being given to Al ₂ O ₃ , ZrO ₂ , TiO ₂ or SiO ₂ powders.

The mixture containing a sol with which the carrier is infiltrated is obtainable from Hydrolysis of a hydrolyzable compound, preferably in a mixture of water and Alcohol, to a hydrolyzate, the hydrolyzable compound being 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 the phosphorous acid, and peptizing the hydrolyzate to that containing a sol Mixture.

It may be advantageous if the hydrolyzable compound is non-hydrolyzable groups in addition to hydrolyzable groups. It is preferred to be hydrolyzed as such Compound an alkyltrialkoxy or dialkyl dialkoxy or trialkylalkoxy compound of Silicon used.

An acid or base which is soluble in water and / or alcohol can be added to the mixture as the hydrolysis and condensation catalyst. Preferably a mineral acid, such as. B. H ₂ SO ₄ , H ₃ PO ₄ , HNO ₃ or HCl are added.

It can furthermore be advantageous if the mixture for infiltrating the carrier next to one Trialkoxysilane as a network former also acidic or basic compounds and water includes. The acidic or basic compounds preferably comprise at least one of the Brönstedt or Lewis acid or base known to those skilled in the art.

Trihydroxysilyl acids are known from EP 0 771 589, EP 0 765 897 and EP 0 582 879. In These publications have made the manufacture of molded acid catalysts based described by trihydroxysilylpropylsulfonic acid and trihydroxysilylpropyl mercaptan.

In a preferred embodiment, the brine or mixtures also contain ceramic particles. The oxides of the elements Si, Al, Zr, Ti are particularly preferred here. These can be present in several particle size fractions. It can be advantageous if the ceramic particles have one or more particle size fractions with particle sizes in the range from 10 to 100 nm, from 100 to 1000 nm and / or from 1 to 5 μm. Coarse particle fractions with particle sizes of 0.1-5 μm, such as B. Al ₂ O ₃ (AlCoA CT3000) or ZrO ₂ (Tosoh TZ3Y), finer particle or agglomerate sizes of 50 nm - 500 nm, such as. B. Aerosil200, AerosilOx50 or Aerosil VP 25, or very fine-scale particles, which, for. B. be used directly as a suspension, such as. B. Levasil200E.

The mixtures are preferred by suitable measures, such as. B. by longer Stirring with a magnetic stirrer or wave stirrer, using an Ultraturrax or attritor mill or homogenized using ultrasound before the actual infiltration is carried out.

Infiltration of the carrier can be done by printing, pressing, pressing, rolling, Doctor knife, spread, dip, spray or pour the mixture onto the permeable carrier. Infiltration with the mixture can be carried out repeatedly become. If necessary, a drying step, preferably an increased one Temperature in a range of 50 to 200 ° C, between repeated infiltration. In In a preferred embodiment, the carrier is infiltrated continuously. It can be advantageous if the carrier is preheated for infiltration.

The mixture can be solidified in the carrier by heating to a temperature of 50 to 300 ° C, preferably 50 to 200 ° C, most preferably 80 to 150 ° C, the heating by heated air, hot air, infrared radiation or Microwave radiation can take place. At a temperature of 80 to 150 ° C the solidification takes place over a time from 1 second to 1 hour, preferably from 10 seconds to 10 minutes and entirely particularly preferably from 1 to 5 minutes.

A membrane electrode unit according to the invention is described below. The Flexible membrane electrode assembly for a fuel cell comprises an anode layer and a cathode layer, each on opposite sides for the Reaction components of the fuel cell reaction impermeable, proton conductive, flexible Electrolyte membrane are provided for a fuel cell, the electrolyte membrane comprises a permeable, flexible, openwork carrier comprising a glass, wherein the carrier is interspersed with a proton conductive gel that is suitable selective To conduct protons through the membrane, and being the anode layer and the cathode layer are porous and each have a catalyst for the anode and cathode reactions, one proton conductive component and optionally a catalyst support.

• a) eine immobilisierte Hydroxysilylalkylsäure von Schwefel oder Phosphor oder ein Salz davon sowie gegebenenfalls ein Oxid von Aluminium, Silizium, Titan, Zirkonium und/oder Phosphor, und/oder
• b) eine Brönstedsäure und ein Oxid von Aluminium, Silizium, Titan, Zirkonium, und/oder Phosphor.

The proton-conductive component of the anode and / or cathode layer and / or the proton-conductive gel of the electrolyte membrane each preferably 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.

The Bronsted acid can e.g. B. sulfuric acid, phosphoric acid, perchloric acid, nitric acid, Hydrochloric acid, sulfurous acid, phosphorous acid and esters thereof and / or one be monomeric or polymeric organic acid.

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 formula n


stands,
in which
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 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 sulfur or phosphorus or a salt thereof with a hydrolyzed compound of phosphorus or a hydrolyzed one Nitrate, oxynitrate, chloride, oxychloride, carbonate, alcoholate, acetate, acetylacetonate one Metal or semi-metal immobilized. In a further preferred embodiment, the Hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof with one 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.

The proton-conductive component of the anode and / or cathode layer may also include proton-conducting materials selected from titanium phosphates, Titanphosphonaten, zirconium phosphates, Zirkoniumphosphonaten, iso- and heteropoly acids, preferably tungstophosphoric acid or silicotungstic acid, or nano-crystalline metal oxides and Al ₂ O ₃ - ZrO ₂ -, TiO ₂ or SiO ₂ powder are preferred.

The membrane electrode assembly according to the invention can preferably be used in a fuel cell at a temperature of at least 80 ° C, preferably at least 100 ° C, and completely are particularly preferably operated at at least 120 ° C. The invention Membrane electrode unit preferably tolerates a bending radius of down to 5000 mm, preferably 100 mm, in particular from down to 50 mm and particularly preferred from down to 20 mm. The inventive method very particularly preferably tolerates Membrane electrode unit has a bending radius of down to 5 mm.

In a special embodiment of the membrane electrode unit according to the invention have the proton conductive component of the anode layer and cathode layer and that proton conductive gel of the electrolyte membrane has the same composition. on the other hand it is also possible that the proton conductive component of the anode layer and / or Cathode layer and / or the membrane are different.

The catalyst may be the same on the anode and cathode sides, in the preferred one The embodiment is different. In a preferred embodiment, the Catalyst carrier in the anode layer and in the cathode layer electrically conductive.

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

The electrolyte membrane can be provided with the electrode in various ways. The way and the order of how the electrically conductive material, catalyst, Electrolyte and any other additives that may be applied to the membrane are at will of the specialist. You just have to make sure that the interface Gas space / catalyst (electrode) / electrolyte is formed. In a special case, the electrically conductive material is omitted as a catalyst carrier, in this case the electrically conductive catalyst directly for the derivation of the electrons from the Membrane electrode assembly.

• A) Bereitstellung einer für die Reaktionskomponenten der Brennstoffzellenreaktion undurchlässigen, protonenleitfähigen, flexiblen Elektrolytmembran für eine Brennstoffzelle, insbesondere einer erfindungsgemäßen Elektrolytmembran, wobei die Elektrolytmembran einen stoffdurchlässigen, flexiblen, durchbrochenen, ein Glas umfassenden Träger umfasst, wobei der Träger mit einem protonenleitfähigen Gel durchsetzt ist, das geeignet ist selektiv Protonen durch die Membran zu leiten,
• B) Bereitstellung jeweils eines Mittels zur Herstellung einer Anodenschicht und einer Kathodenschicht, wobei das Mittel jeweils umfasst:
  • 1. eine kondensierbare Komponente, die nach der Kondensation der Elektrodenschicht Protonenleitfähigkeit verleiht,
  • 2. einen Katalysator, der die Anodenreaktion bzw. die Kathodenreaktion katalysiert, oder eine Vorstufenverbindung des Katalysators,
  • 3. gegebenenfalls einen Katalysatorträger und
  • 4. gegebenenfalls einen Porenbildner,
• C) Aufbringen der Mittel aus Stufe (B) auf jeweils eine Seite der Elektrolytmembran aus Stufe (A) zur Bildung einer Beschichtung,
• D) Schaffung eines festen Verbundes zwischen den Beschichtungen und der Elektrolytmembran unter Ausbildung einer porösen, protonenleitfähigen Anodenschicht oder Kathodenschicht, wobei die Ausbildung der Anodenschicht und der Kathodenschicht gleichzeitig oder nacheinander erfolgen kann.

The method according to the invention for producing a membrane electrode unit according to the invention comprises the following steps:

• A) provision of a proton-conductive, flexible electrolyte membrane which is impermeable to the reaction components of the fuel cell reaction, for a fuel cell, in particular an electrolyte membrane according to the invention, the electrolyte membrane comprising a permeable, flexible, openwork, glass-containing carrier, the carrier being permeated with a proton-conductive gel, that is capable of selectively passing 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 catalyst support 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.

The application of the agent in step (C) can, for. B. by printing, pressing, Pressing in, rolling up, knife application, spreading on, dipping, spraying or pouring on.

• 1. Herstellung eines Sols, umfassend
  eine Hydroxysilylalkylsäure des Schwefels oder Phosphors bzw. deren Salz und gegebenenfalls eine die Hydroxysilylalkylsäure des Schwefels oder Phosphors bzw. deren Salz immobilisierende hydrolysierbare Verbindung des Phosphors
  oder ein hydrolysierbares Nitrat, Oxynitrat, Chlorid, Oxychlorid, Carbonat, Alkoholat, Acetat, Acetylacetonat eines Metalls oder Halbmetalls, vorzugsweise Phosphorsäuremethylester, Diethylphosphit (DEP), Diethylethylphosphonat (DEEP), Titanpropylat, Titanethylat, Tetraethylorthosilikat (TEOS) oder Tetramethylorthosilikat (TMOS), Zirkoniumnitrat, Zirkoniumoxynitrat, Zirkoniumpropylat, Zirkoniumacetat oder Zirkoniumacetylacetonat,
• 2. Dispergieren des Katalysators und gegebenenfalls des Katalysatorträgers und Porenbildners in dem Sol aus (S1).

The agent according to step (B) for producing an anode layer or a cathode layer is preferably a suspension which is obtainable from

• 1. Preparation of a sol, comprising
  a hydroxysilylalkyl acid of sulfur or phosphorus or its salt and optionally a hydrolyzable compound of phosphorus immobilizing 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 methylphosphate, diethylphosphite (DEP), diethylethylphosphonate (DEEP), titanium propylate, titaniumethylate, tetraethylorthosilicate (TEOS) or tetraethyl orthosilicate (TEOS) or Zirconium nitrate, zirconium oxynitrate, zirconium propylate, zirconium acetate or zirconium acetylacetonate,
• 2. Dispersing the catalyst and optionally the catalyst support and pore former in the sol from (S1).

• 1. Hydrolyse einer hydrolysierbaren Verbindung zu einem Hydrolysat, wobei die hydrolysierbare Verbindung ausgewählt ist aus
  einer hydrolysierbaren Verbindung des Phosphors oder
  hydrolysierbaren Nitraten, Oxynitraten, Chloriden, Oxychloriden, Carbonaten, Alkoholaten, Acetaten, Acetylacetonaten eines Metalls oder Halbmetalls, vorzugsweise Aluminiumalkoholaten, Vanadium-alkoholaten, Titanpropylat, Titanethylat, Zirkoniumnitrat, Zirkoniumoxynitrat, Zirkoniumpropylat, Zirkoniumacetat oder Zirkoniumacetylacetonat, oder
  Metallsäuren des Aluminiums, Siliziums, Titans, Vanadiums, Antimons, Zinns, Bleis, Chroms, Wolframs, Molybdäns, Mangans, wobei Wolframphosphorsäure und Siliziumwolframsäure bevorzugt ist,
• 2. Peptisierung des Hydrolysats mit einer Säure zu einer Dispersion,
• 3. Vermischen der Dispersion mit einem nanokristallinen protonenleitenden Metalloxid, vorzugsweise Al₂O₃-, ZrO₂-, TiO₂- oder SiO₂-Pulver,
• 4. Dispergieren des Katalysators und gegebenenfalls des Trägers und Porenbildners.

The agent according to step (B) for producing an anode layer or a cathode layer is very particularly preferably 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 acetate
  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 form a dispersion,
• 3. Mixing the dispersion with a nanocrystalline proton-conducting 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.

It can be advantageous if the means for producing an anode layer and a Cathode layer can be 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 from 50 to 300 ° C, preferably 50 to 200 ° C, most preferably 80 to 150 ° C is heated.

• 1. Aufbringen des Mittels zur Herstellung einer Anodenschicht oder Kathodenschicht auf eine Stützmembran, vorzugsweise aus Polytetrafluorethylen,
• 2. Antrocknen der unter (M1) erhaltenen Beschichtung,
• 3. Aufpressen der angetrockneten Beschichtung auf die Elektrolytmembran bei einer Temperatur von 20 bis 300°C, vorzugsweise 50 bis 200°C, ganz besonders bevorzugt 80 bis 150°C,
• 4. Entfernen der Stützmembran insbesondere durch mechanisches Ablösen, chemisches Auflösen, oder Pyrolisieren oder
• 5. Aufbringen des Mittels zur Herstellung einer Anodenschicht oder Kathodenschicht auf eine Stützmembran, vorzugsweise aus Kohlepapier oder einem elektrisch leitfähigen Vlies oder Gewebe,
• 6. Antrocknen der unter (N1) erhaltenen Beschichtung zur Herstellung einer beschichteten Stützmembran,
• 7. Aufpressen der beschichteten Stützmembran auf die Elektrolytmembran bei einer Temperatur von Raumtemperatur bis 300°C, vorzugsweise 50 bis 200°C, ganz besonders bevorzugt 80 bis 150°C umfassen.

The method according to the invention can also include the steps:

• 1. Applying the agent for producing an anode layer or cathode layer to a support membrane, preferably made of polytetrafluoroethylene,
• 2. drying of the coating obtained under (M1),
• 3. pressing the dried coating onto the electrolyte membrane at a temperature of 20 to 300 ° C., preferably 50 to 200 ° C., very particularly preferably 80 to 150 ° C.,
• 4. Removing the support membrane, in particular by mechanical detachment, chemical dissolving, or pyrolizing or
• 5. 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 or fabric,
• 6. drying of the coating obtained under (N1) to produce a coated support membrane,
• 7. Press the coated support membrane onto the electrolyte membrane at a temperature of from room temperature to 300 ° C., preferably 50 to 200 ° C., very particularly preferably 80 to 150 ° C.

• a) ein Katalysatormetallsalz, vorzugsweise Hexachloroplatinsäure umfasst
• b) nach dem Aufbringen der Mittel durch Schritt (C) das Katalysatormetallsalz zu einem Katalysator, der die Anodenreaktion oder die Kathodenreaktion katalysiert, reduziert wird,
• c) in Schritt (D) eine offenporige Gasdiffusionselektrode, vorzugsweise ein offenporiges Kohlepapier, auf den Katalysator aufgepresst oder mit einem elektrisch leitfähigen Klebstoff auf den Katalysator geklebt wird.

It can be advantageous if in step (B) the agent is provided in each case when providing an agent for producing an anode layer and a cathode layer

• a) comprises a catalyst metal salt, preferably hexachloroplatinic acid
• b) 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,
• c) in step (D), an open-pore gas diffusion electrode, preferably an open-pore carbon paper, is pressed onto the catalyst or glued to the catalyst with an electrically conductive adhesive.

The inventive method can be carried out so that the application of the Repeatedly carried out by means of producing an anode layer or cathode layer and optionally a drying step, preferably at an elevated temperature in a range from 50 to 300 ° C, preferably from 50 to 200 ° C and very particularly preferably at an elevated temperature of 80 to 150 ° C between the repeated The application is carried out.

It can be advantageous if the agent is used to produce an anode layer or cathode layer on a flexible electrolyte membrane unrolled from a first roll or flexible support membrane. In particular, it can be advantageous if the Application of the agent for producing an anode layer or cathode layer done continuously. It can be particularly advantageous if the application of the agent for Production of an anode layer or cathode layer on a heated electrolyte or Support membrane is made.

To create a firm bond between the coatings and the The composite electrolyte membrane is preferably, at a temperature of 50 to 300 ° C, preferably 50 to 200 ° C, most preferably 80 to 150 ° C heated. The warming can be done using heated air, hot air, infrared radiation or microwave radiation.

In a special embodiment, the membrane electrode assembly is manufactured on the electrolyte membrane according to the invention 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 But can also contain other additives that have the properties of Improve membrane electrode assembly. The soot can also be caused by other, electrically conductive Materials (such as metal powder, metal oxide powder, carbon, coal) are replaced. In In a special embodiment, a metal or Semimetal oxide powder (such as Aerosil) is used. This ink is then, for example by screen printing, knife coating, spraying on, rolling on or by dipping on the membrane applied.

The ink can contain all proton-conducting materials that are also used to infiltrate the carrier. 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 gel of the electrolyte membrane, which for the Reaction components of the fuel cell reaction must be impermeable, both Both cathode and anode have a large porosity so that the reaction gases, such as Hydrogen and oxygen, without inhibition of mass transfer to the interface between catalyst and Electrolyte can be introduced. This porosity can be measured, for example Use of metal oxide particles with a suitable particle size and of organic pore formers in the ink or by a suitable solvent content in the Affect ink.

• 1. eine kondensierbare Komponente, die nach der Kondensation einer Anodenschicht oder einer Kathodenschicht einer Membranelektrodeneinheit einer Brennstoffzelle Protonenleitfähigkeit verleiht,
• 2. einen Katalysator, der die Anodenreaktion oder die Kathodenreaktion in einer Brennstoffzelle katalysiert, oder eine Vorläuferverbindung des Katalysators,
• 3. gegebenenfalls einen Katalysatorträger
• 4. gegebenenfalls einen Porenbildner, und
• 5. gegebenenfalls Additive zur Verbesserung von Schaumverhalten, Viskosität und Haftung.

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

• 1. a condensable component which, after the condensation of an anode layer or a cathode layer of a membrane electrode assembly, imparts proton conductivity to a fuel cell,
• 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
• 4. optionally a pore former, and
• 5. optionally additives to improve foam behavior, viscosity and adhesion.

• A) hydrolysierbaren Verbindung des Phosphors und/oder
  hydrolysierbaren Nitraten, Oxynitraten, Chloriden, Oxychloriden, Carbonaten, Alkoholaten, Acetaten, Acetylacetonaten eines Metalls oder Halbmetalls, vorzugsweise Aluminiumalkoholaten, Vanadium-alkoholaten, Titanpropylat, Titanethylat, Zirkoniumnitrat, Zirkoniumoxynitrat, Zirkoniumpropylat, Zirkoniumacetat oder Zirkoniumacetylacetonat, und/oder
  Metallsäuren des Aluminiums, Titans, Vanadiums, Antimons, Zinns, Bleis, Chroms, Wolframs, Molybdäns, Mangans, wobei Wolframphosphorsäure und Siliziumwolframsäure bevorzugt sind, und/oder
• B) einer immobilisierbaren Hydroxysilylalkylsäure von Schwefel oder Phosphor oder ein Salz davon und in einer besonders bevorzugten Ausführungsform zusätzlich eine die Hydroxysilylalkylsäure des Schwefels oder Phosphors bzw. deren Salz immobilisierende hydrolysierbare Verbindung des Phosphors oder ein hydrolisierbares Nitrat, Oxynitrat, Chlorid, Oxychlorid, Carbonat, Alkoholat, Acetat, Acetylacetonat eines Metalls oder Halbmetalls, vorzugsweise Phosphorsäuremethylester, Diethylphosphit (DEP), Diethylethylphosphonat (DEEP) Titanpropylat, Titanethylat, Tetraethylorthosilikat (TEOS) oder Tetramethylorthosilikat (TMOS), Zirkoniumnitrat, Zirkoniumoxynitrat, Zirkoniumpropylat, Zirkoniumacetat oder Zirkoniumacetylacetonat.

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 acetate or zirconium acetate
  Metal acids of aluminum, titanium, vanadium, antimony, tin, lead, chromium, tungsten, molybdenum, manganese, with tungsten phosphoric acid and silicon tungsten acid being preferred, and / or
• B) an immobilizable hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof and, in a particularly preferred embodiment, additionally a hydrolyzable compound of phosphorus immobilizing 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 phosphate, diethylphosphite (DEP), diethylethylphosphonate (DEEP) titanium propylate, titanium ethylate, tetraethylorthosilicate (TEOS) or tetramethylorthosilicate (TMOS), zirconium nitrate, zirconium oxynium acetate, zirconium oxonium acetate.

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

The catalyst or the precursor compound of the catalyst preferably comprises platinum, Palladium and / or ruthenium or an alloy containing one or more of these metals contains.

The pore former, which is optionally contained in the ink, can be an organic and / or be inorganic material, which is preferred at a temperature between 50 and 600 ° C. decomposed between 100 and 250 ° C. In particular, the inorganic pore former Be ammonium carbonate or ammonium bicarbonate.

The catalyst support, which is optionally contained in the ink, is preferably electrical conductive and preferably comprises carbon black, metal powder, metal oxide powder, carbon or Coal.

In a further embodiment, a prefabricated gas distributor, the Gas diffusion electrode consisting of an electrically conductive material (e.g. a porous Carbon fleece), catalyst and electrolyte contains, are applied directly to the membrane. In the simplest case, the gas distributor and membrane are fixed by a Pressing process. For this it is necessary that the membrane or gas distributor at the Press temperature have thermoplastic properties. The gas distributor can also be fixed on the membrane by an adhesive. This adhesive must be ion-conductive Have properties and can in principle from the material classes already mentioned above consist. For example, a metal oxide sol can be used as the adhesive additionally contains a hydroxysilyl acid. Finally, the gas distributor can also "in situ" applied in the final stage of membrane or gas diffusion electrode manufacture become. At this stage, the proton-conducting material is in the gas distributor or in the membrane not yet 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 a open-pore gas diffusion electrode (such as an open-pore carbon paper). For this purpose, e.g. B. applied a metal salt or an acid to the surface and in one second step to be reduced to metal. For example, platinum can be Apply hexachloroplatinic acid and reduce to metal. In the last step the Lead electrode by a pressing process or by an electrically conductive adhesive fixed. The solution containing the metal precursor can also be a compound contain, which is already proton conductive or at least at the end of the manufacturing process is ionic. Suitable materials come again from those already mentioned above proton-conducting substances in question.

In this way, a membrane electrode unit is obtained which, in a fuel cell, especially in a direct methanol fuel cell or a reformate fuel cell, can be used.

The electrolyte membranes according to the invention can, for. B. in a fuel cell, especially in a direct methanol fuel cell or a reformate fuel cell be used. In particular, the electrolyte membrane according to the invention can Manufacture of a membrane electrode assembly, a fuel cell, or one Fuel cell stacks are used.

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

Accordingly, there are also fuel cells with an electrolyte membrane according to the invention and / or a membrane electrode unit according to the invention the subject of the present Invention and thus also mobile or stationary system with a membrane electrode unit, a fuel cell or a fuel cell stack containing an inventive Electrolyte membrane or a membrane electrode assembly according to the invention. Preferably are the mobile or stationary systems vehicles or home energy systems.

The present invention is explained in more detail with reference to FIGS. 1a and b and 2a and b, without the invention being restricted to these embodiments.

A section of a conventional electrolyte membrane is shown schematically in FIG. 1a. A glass thread G can be seen, which is coated with ceramic particles K. The electrolyte E is present between these particles. A glass thread G can again be seen in FIG. 1b. However, the glass filament is surrounded by the gel-like electrolyte E, which contains stochastically distributed ceramic particles. It can be clearly seen that in the embodiment of the electrolyte membrane according to the invention, the volume available to the electrolyte is considerably larger than in the case of conventional electrolyte membranes based on ceramic microfiltration membranes.

The situation is schematically represented in FIG. 2a as in FIG. 1a, with the difference that an optical fiber is shown which has three filaments G '. Because of the low porosity of the ceramic coating K surrounding the glass fiber, the space for the electrolyte E is virtually inaccessible. The electrolyte E is located between the ceramic particles K. The situation is different in FIG. 2b. Here, the gel-like electrolyte is also present between the filaments G 'of the glass fiber. The dead volume, i.e. the volume not available for proton conductivity, in an electrolyte membrane designed in this way is therefore significantly lower than in conventional membranes. Also in Fig. 2b, the gel-like electrolyte back to ceramic particles in random distribution. The distribution as shown in Fig. 1b and Fig. 2b can certainly be assumed to be ideal. Due to the manufacturing process, ceramic particles that may be present during infiltration may collect in particular on the filaments (filtration effect). To counteract this, it can be advantageous if the mixture (the sol) is gelled to a fairly high degree of condensation before infiltration, so that a more viscous paste is formed which is introduced into the carrier. In this way it is possible to almost maintain the statistical distribution of the ceramic particles.

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

EXAMPLES example 1 Production of a proton-conducting electrolyte membrane according to the invention (CPEM) Example 1a Production of a cPEM based on Trihydroxisilylpropylsulfonsäure / Levasil®

10 g of a 30% trihydroxysilylpropylsulfonic acid are dissolved in 50 g Levasil200®. On S-glass fabric with a thickness of 70 µm is used in a continuous rolling process coated this solution and dried briefly at 150 ° C.

Example 1b Production of a cPEM based on trihydroxysilylpropylsulfonic acid / TEOS

10 g of a 30% trihydroxysilylpropylsulfonic acid are dissolved in 40 g of ethanol. To this The solution is first given a few drops of HCl and then 30 ml with vigorous stirring Dynasilan A® and stir the solution for another 24 h.

A solution of 2% Dynasilan A® in ethanol is mixed with a few drops of HCl. To Continue stirring for 24 h, an E-glass fabric with a thickness of 30 µm is sprayed with this solution and dried with hot air at 400 ° C.

The solution containing trihydroxysilylpropylsulfonic acid is then applied in a doctor blade process applied to the treated E-glass fabric and the membrane dried at 100 ° C.

Example 1c Production of a cPEM based on a mineral acid

8 g of a 20% solution of precipitated silica (Levasil®) are mixed with 1 g of diethyl phosphite, 1 g of H ₂ SO ₄ and 1 g of ethanol. After 1 h, 5% by weight of Aerosil200 is added to the sol and the suspension is homogenized for a further 30 min. In a continuous rolling process, an S-glass fabric is coated with it and the membrane is dried at 100 ° C.

Example 1d Production of a cPEM based on a mineral acid with Double coating

For better infiltration, the membrane from Example 1c is again coated with the Aerosil®-free one Sol from 1c coated on the back and also dried at 100 ° C.

This membrane has an LF of 140 mS / cm at 45% relative air humidity (RH) and 220 mS / cm at 85% RH. Due to the very good flexibility, it can be very easily used in the Install fuel cell and shows good performance.

Example 1e Production of several cPEMs based on a mineral acid with a high proportion of Al ₂ O ₃

120 g of a 20% solution of precipitated silica (Levasil200®, Bayer) are mixed with 10 g diethyl phosphite (DEP), 10 g ethanol and 10, 15 or 20 g H ₂ SO ₄ . After 1 h, 5% by weight of Aerosil200® or VP 25® (both Degussa) are added to the sol and the suspension is homogenized for a further 30 min. After the sol has been homogenized for 24 hours, a further 20, 30 or 40% by weight of Al ₂ O ₃ (CT3000®, AlCoA) is optionally added. In a continuous rolling process, an approximately 70 µm thick S-glass fabric is treated and the membrane is dried at 120 ° C for a few minutes using hot air. Table 1 below shows the particular composition of the suspension with which the glass fabric was treated and the conductivities of the membranes obtained (cPEMs).

Example 2 Coating a cPEM with diffusion barriers Example 2a Coating with pure Nafion

A membrane according to Example 1d is in a continuous rolling process with a 5% Nafion® solution coated and dried at 100 ° C. The LF of the entire membrane decreases somewhat, but the membrane is suitable for the DMFC.

Example 2b Coating with Nafion / TEOS

10 ml of Dynasil A® are added to 10 ml of 5% Nafion® solution with vigorous stirring added and stirred until there is only a clear phase. A membrane according to Example 1d, in a continuous rolling process with this solution coated and dried at 100 ° C.

Example 2c Coating with Nafion / TEOS / ethanol

10 ml of Dynasil A® are dissolved in 10 ml of 5% Nafion® solution with vigorous stirring added in 10 ml of ethanol and stirring continued for a short time. A membrane according to the example 1e5, is coated on both sides with this solution in a continuous rolling process and dried at 100 ° C.

Example 2d Coating with trihydroxysilylpropylsulfonic acid / Levasil

10 g of a 30% trihydroxysilylpropylsulfonic acid are dissolved in 50 g Levasil200®. A Membrane according to Example 1d, is in a continuous rolling process with this Solution coated and dried at 100 ° C.

Example 2e Coating with trihydroxysilylpropylsulfonic acid / TEOS

10 g of a 30% trihydroxysilylpropylsulfonic acid are dissolved in 40 g of ethanol. To this The solution is first given a few drops of HCl and then 30 ml with vigorous stirring Dynasilan A® and stir the solution for another 24 h. A membrane according to Example 1d is in a continuous rolling process coated with this solution and at 100 ° C dried.

Example 2f Coated with zirconium phosphate

A membrane produced according to Example 1e5 is first coated on both sides by means of a doctor blade with a thin layer of zirconium propylate. The alcoholate is hydrolyzed in the presence of air humidity. The freshly precipitated zirconium hydroxide / oxide is then reacted with H ₃ PO ₄ and the membrane is briefly dried at 200 ° C. in order to solidify the zirconium phosphate formed. This thin layer is then insoluble in water and prevents the electrolyte from bleeding out.

Example 3 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 approximately 0.2 mg / cm ² or 0.5 mg / cm ² can be achieved in the electrode.

Example 4 Production of an anode ink

100 ml of titanium isopropylate 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 boiling point 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 3.

Example 5 Production of an anode ink

20 g of aluminum alcoholate and 17 g of vanadium alcoholate are hydrolyzed with 20 g of water and the precipitate formed is peptized with 120 g of nitric acid (25%). This solution is stirred until clear and after adding 40 g of titanium dioxide from Degussa (P25) is stirred until all agglomerates have dissolved. After setting a pH of about 6, the catalyst is dispersed therein as described in Example 3.

Example 6 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 level of about 0.15 mg / cm ² or 0.25 mg / cm ² can be achieved in the electrode ,

Example 7 Production of a cathode ink

20 g of methyltriethoxysilane, 20 g of tetraethyl orthosilicate and 10 g of aluminum trichloride hydrolyzed with 50 g water in 200 g ethanol. 190 g of zeolite USY (CBV 600 from Zeolyst). The mixture is stirred until all agglomerates are gone have dissolved and then the catalyst is as described in Example 6 therein dispersed.

Example 8 Manufacture of a membrane electrode assembly Example 8a Manufacture of a membrane electrode assembly

A membrane according to Example 2c is screen printed with the ink according to Example 3 first printed on the front. This page serves in the later Membrane electrode unit as an anode. The printed membrane is at a temperature of 150 ° C dried. In addition to the escape of the solvent, there is also a Immobilization of the silylpropylsulfonic acid.

In the second step, the membrane on the back, which will later serve as the cathode, is attached printed on the ink from Example 6. Even now the printed membrane is in turn at one Dried temperature of 150 ° C whereby the solvent escapes and at the same time it becomes a Immobilization of the silylpropylsulfonic acid comes. Since the cathode is hydrophobic, the Operation of the membrane electrode assembly in the fuel cell makes the product water easily escape. This membrane electrode assembly can be used in a direct methanol fuel cell or a reformate fuel cell can be installed.

Example 8b Manufacture of a membrane electrode assembly

To produce the electrodes, both the anode ink according to Example 4 and Cathode ink according to Example 7 each applied to an electrically conductive carbon paper. The solvent is removed by heat treatment at a temperature of 150 ° C and immobilized the proton-conductive component. These two gas diffusion electrodes are once with a proton conductive membrane according to Example 1e5 and once with a proton-conductive membrane according to Example 2c to form a membrane electrode assembly pressed, which can then be installed in the fuel cell.

Example 9 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 become one on a proton conductive membrane according to Example 1e5 and the other on one proton-conductive membrane pressed according to Example 2c. The pressure is applied via a graphitic gas distribution plate, which also serves for electrical contacting. On the Pure hydrogen is added to the anode side and pure oxygen is added to the cathode side Commitment. Both gases are moistened via water vapor saturators (so-called "bubblers").

Comparative example

A fuel cell was made as described in Example 9, except that as proton-conducting membrane, a conventional Nafion®117 membrane was used. It it was found that the proton conductivity when using a Nafion membrane a relative humidity of less than 100% and the Surface resistance increased sharply so that the fuel cell can no longer be operated could. On the other hand, a membrane according to the invention can also be used in a relative Humidity operated, the anode side at about 10% and the cathode side at about 5% was without significantly impairing the function of the fuel cell.

Claims (73)

1. Impermeable to the reaction components of a fuel cell reaction Proton-conductive, flexible electrolyte membrane for a fuel cell, comprising a flexible, openwork carrier comprising a glass, the carrier with a proton-conductive gel is penetrated, which is suitable for selectively protons through the To guide the membrane. 2. Electrolyte membrane according to claim 1, characterized in that the proton-conductive gel a) an immobilized hydroxysilylalkyl acid of sulfur or phosphorus, and optionally an oxide of aluminum, silicon, titanium, zirconium and / or phosphorus as a network former, and / or b) comprises a Bronsted acid and an oxide of aluminum, silicon, titanium, zirconium, and / or phosphorus as a network former. 3. Proton-conductive, flexible electrolyte membrane for a fuel cell, impermeable to the reaction components of a fuel cell reaction, obtainable from a) Infiltration of a flexible, openwork, glass-enclosed carrier 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 b) solidification of the mixture infiltrating the carrier in order to create a gel which penetrates the carrier and is suitable for selectively guiding protons through the membrane. 4. electrolyte membrane according to one of claims 2 or 3, characterized, that the Bronsted acid sulfuric acid, phosphoric acid, perchloric acid, nitric acid, Hydrochloric acid, sulfurous acid, phosphorous acid and esters thereof and / or comprises a monomeric or polymeric organic acid. 5. Electrolyte membrane according to one of claims 2 to 4, characterized in that the hydroxysilylalkyl acid of sulfur or phosphorus 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,
in which
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 or H and
R ^{3 represents} M or a methyl, ethyl, propyl or butyl radical. 6. electrolyte membrane according to claim 5, characterized, that the hydroxysilylalkyl acid of sulfur or phosphorus Trihydroxysilylpropylsulfonic acid, trihydroxysilylpropylmethylphosphonic acid or Dihydroxysilylpropyl sulfondioic acid. 7. electrolyte membrane according to one of claims 2 to 6, characterized, that the hydroxysilylalkyl acid of sulfur or phosphorus is hydrolyzed with a Compound of phosphorus or a hydrolyzed nitrate, oxynitrate, chloride, Oxychloride, carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal or 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, zirconium acetylacetonate, phosphoric acid methyl ester or is immobilized with precipitated silica. 8. electrolyte membrane according to one of claims 1 to 7, characterized, that the volume ratio of gel to carrier is at least 30 to 70. 9. Electrolyte membrane according to one of claims 1 to 8, characterized in that the gel has ceramic particles of at least one oxide selected from the series Al ₂ O ₃ , SiO ₂ , ZrO ₂ or TiO ₂ . 10. electrolyte membrane according to one of claims 1 to 9, characterized, that the ceramic particles have one or more particle size fractions Particle sizes in the range from 10 to 100 nm, from 100 to 1000 nm and / or from 1 to 5 µm exhibit. 11. Electrolyte membrane according to one of claims 1 to 10, characterized in that the gel has proton-conducting substances selected from the titanium phosphates, titanium phosphonates, zirconium phosphates, zirconium phosphonates, iso- and heteropolyacids, preferably tungsten phosphoric acid or silicon tungstic acid, or nanocrystalline metal oxides, wherein Al ₂ O ₃ , ZrO ₂ , TiO ₂ or SiO ₂ powder are preferred. 12. Electrolyte membrane according to one of claims 1 to 11, characterized in that the glass is aluminosilicate glass containing at least 60 wt .-% SiO ₂ and at least 10 wt .-% Al ₂ O ₃ . 13. Electrolyte membrane according to one of claims 1 to 12, characterized in that the glass of the carrier has the following composition:
from 64 to 66% by weight SiO ₂ ,
from 24 to 25% by weight of Al ₂ O ₃ ,
from 9 to 12% by weight of MgO and
less than 0.2% by weight of CaO, Na ₂ O, K ₂ O and / or Fe ₂ O ₃ . 14. Electrolyte membrane according to one of claims 1 to 13, characterized in that the carrier contains fibers or filaments made of glass, which are equipped with an acid-resistant coating of α-Al ₂ O ₃ , ZrO ₂ or TiO ₂ and the glass preferably has the following composition having:
from 52 to 56% by weight of SiO ₂
from 12 to 16% by weight of Al ₂ O ₃
from 5 to 10% by weight of B ₂ O ₃
from 16 to 25 wt% CaO
from 0 to 5 wt% MgO
less than 2% by weight Na ₂ O + K ₂ O
less than 1.5% by weight of TiO ₂
less than 1% by weight of Fe ₂ O ₃ . 15. electrolyte membrane according to one of claims 1 to 14, characterized, that the carrier comprises a fabric or fleece. 16. electrolyte membrane according to claim 15, characterized, that the carrier fibers and / or filaments with a diameter of 1 to 150 microns, preferably 1 to 20 µm, and / or threads with a diameter of 5 to 150 µm, preferably 10 to 70 microns. 17. electrolyte membrane according to claim 15 or 16, characterized, that the carrier is a fabric with a mesh size of 5 to 500 μm, preferably 10 up to 200 µm. 18. Electrolyte membrane according to one of claims 1 to 17, characterized, that they are up to a temperature of at least 80 ° C, preferably up to at least 100 ° C, and very particularly preferably is stable up to at least 120 ° C. 19. Electrolyte membrane according to one of claims 1 to 18, characterized, that the carrier has a thickness in the range from 10 to 150 μm, preferably 10 to 80 μm, very particularly preferably has 10 to 50 microns. 20. Electrolyte membrane according to one of claims 1 to 19, characterized, that they have a bending radius of down to 500 m, preferably down to 10 mm, very particularly preferably tolerated from down to 5 mm. 21. Electrolyte membrane according to one of claims 1 to 20, characterized, that at room temperature and with a relative humidity of maximum 40% a conductivity of at least 5 mS / cm, preferably at least 20 mS / cm, whole particularly preferably has at least 50 mS / cm. 22. Electrolyte membrane according to one of claims 1 to 21, characterized, that the electrolyte membrane has an outer proton conductive on at least one side Has coating that is insoluble in water and methanol. 23. electrolyte membrane according to claim 22, characterized, that the electrolyte membrane has an outer proton-conductive coating on both sides which is insoluble in water and methanol. 24. electrolyte membrane according to one of claims 22 or 23, characterized, that the polymeric proton conductor, which is insoluble in water and methanol, selected from Nafion®, sulfonated or phosphonated polyphenyl sulfones, Polyimides, polyoxazoles, polytriazoles, polybenzimidazoles, polyether ether ketones (PEEK), polyether ketones (PEK), or inorganic proton conductors, selected from Sulfonic or phosphonic acids, Zr or Ti phosphates, phosphonates or Sulfoarylphosphonates or mixtures of organic and inorganic proton conductors having. 25. A method for producing an electrolyte membrane according to one of claims 1 to 24, characterized in that the method comprises the following steps: a) Infiltration of a flexible, openwork, glass-enclosed carrier 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 b) solidification of the mixture infiltrating the carrier in order to create a gel which penetrates the carrier and is suitable for selectively guiding protons through the membrane. 26. The method of claim 25, 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 phosphorous acid, 2. (a1-2) peptizing the hydrolyzate to a sol. 27. The method according to claim 25 or 26, characterized in that the mixture 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 metal oxides, wherein Al ₂ O ₃ -, ZrO ₂ -, TiO ₂ or SiO ₂ powder are preferred. 28. The method according to any one of claims 25 to 27, wherein the infiltration by printing, Pressing on, pressing in, rolling up, knife application, spreading on, dipping, spraying or The mixture is poured onto the permeable carrier. 29. The method according to any one of claims 25 to 28, wherein the infiltration with the mixture is carried out repeatedly and optionally a drying step, preferably at an elevated temperature in a range of 50 to 200 ° C, between the repeated Infiltration takes place. 30. The method according to any one of claims 25 to 29, wherein the infiltration of the permeable carrier takes place continuously. 31. The method according to any one of claims 25 to 30, wherein the solidification by heating to a temperature of 50 to 300 ° C, preferably 50 to 200 ° C, very particularly preferably 80 to 150 ° C. 32. The method according to claim 30 or 31, wherein the heating by heated air, Hot air, infrared radiation or microwave radiation takes place. 33. Flexible membrane electrode assembly for a fuel cell, with an electrical conductive anode and cathode layers, each on opposite sides of one impermeable to the reaction components of the fuel cell reaction, proton conductive, flexible electrolyte membrane for a fuel cell, especially after one of claims 1 to 24, are provided, wherein the electrolyte membrane comprises a flexible, openwork carrier comprising a glass, the carrier comprising a proton-conductive gel is penetrated, which is suitable for selectively protons through the Conduct membrane, and wherein the anode layer and the cathode layer are porous and one catalyst each for the anode and cathode reactions, one proton conductive Component and optionally include a catalyst support. 34. Membrane electrode unit according to claim 33, wherein the proton-conductive component of the anode and / or cathode layer and / or the electrolyte membrane 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. 35. membrane electrode assembly according to claim 34, characterized, that the Bronsted acid sulfuric acid, phosphoric acid, perchloric acid, nitric acid, Hydrochloric acid, sulfurous acid, phosphorous acid and esters thereof and / or comprises a monomeric or polymeric organic acid. 36. Membrane electrode unit according to claim 34, 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,
in which
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 or H and
R ^{3 represents} M or a methyl, ethyl, propyl or butyl radical. 37. Membrane electrode unit according to claim 36, wherein the hydroxysilylalkyl acid Sulfur or phosphorus trihydroxysilylpropylsulfonic acid, Is trihydroxysilylpropylmethylphosphonic acid or dihydroxysilylpropylsulfondioic acid. 38. membrane electrode assembly according to one of claims 34, 36 or 37, characterized, that having the hydroxysilylalkyl acid of sulfur or phosphorus or a salt thereof a hydrolyzed compound of phosphorus or a hydrolyzed nitrate, Oxynitrate, chloride, oxychloride, carbonate, alcoholate, acetate, acetylacetonate of a metal or semimetal or with a hydrolyzed compound obtained by hydrolysis of 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, zirconium acetylacetonate, Phosphoric acid methyl ester or immobilized with precipitated silica. 39. Membrane electrode unit according to one of claims 33 to 38, characterized in that the proton-conducting component has proton-conducting substances selected from the titanium phosphates, titanium phosphonates, zirconium phosphates, zirconium phosphonates, iso- and heteropolyacids, preferably tungsten phosphoric acid or silicon tungstic acid, or nanocrystalline metal oxides, where Al ₂ O ₃ , ZrO ₂ , TiO ₂ or SiO ₂ powder are preferred. 40. membrane electrode assembly according to one of claims 33 to 39, characterized, that they are at a temperature of at least 80 ° C, preferably at least 100 ° C, and very particularly preferably can be operated at at least 120 ° C. 41. Membrane electrode unit according to one of claims 33 to 40, which has a bending radius of at least 5000 mm, preferably of at least 100 mm, very particularly preferably tolerated by at least 50 mm. 42. Membrane electrode unit according to one of claims 33 to 41, wherein the proton conductive component of the anode layer and cathode layer and that proton conductive gel of the electrolyte membrane have the same composition. 43. Membrane electrode unit according to one of claims 33 to 42, wherein the proton conductive component of the anode layer and the cathode layer the same Have composition. 44. Membrane electrode unit according to one of claims 33 to 43, wherein the anode layer and the cathode layer have different catalysts. 45. Membrane electrode unit according to one of claims 33 to 44, wherein the Catalyst carrier in the anode layer and in the cathode layer is electrically conductive. 46. A method for producing a membrane electrode unit according to one of claims 33 to 45, 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 24, wherein the electrolyte membrane comprises a permeable, flexible, openwork, glass-comprising carrier, the carrier having a proton-conductive Gel is penetrated, which is capable of 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 catalyst support 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. 47. The method of claim 46, wherein the application of the agent in step (C) by Printing on, pressing on, pressing in, rolling up, knife coating, spreading on, dipping, Spraying or pouring takes place. 48. The method according to any one of claims 46 or 47, 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 sol, comprising
a hydroxysilylalkyl acid of sulfur or phosphorus or its salt and optionally a hydrolyzable compound of phosphorus immobilizing 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 methylphosphate, diethylphosphite (DEP), diethylethylphosphonate (DEEP), titanium propylate, titaniumethylate, tetraethylorthosilicate (TEOS) or tetraethyltosilicate (TEOS) or Zirconium nitrate, zirconium oxynitrate, zirconium propylate, zirconium acetate or zirconium acetylacetonate, 2. Dispersing the catalyst and optionally the catalyst support and pore former in the sol from (S1). 49. The method according to any one of claims 46 to 48, 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 acetate
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 form a dispersion, 3. Mixing the dispersion with a nanocrystalline proton-conducting 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. 50. The method according to any one of claims 46 to 49, wherein the means for producing a Anode layer and a cathode layer are printed in step (C) and for 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 in step (D) to a temperature of 50 to 300 ° C, preferably 50 to 200 ° C, most preferably 80 to 150 ° C is heated. 51. The method according to claim 48 or 49, characterized by 1. Applying the agent for producing an anode layer or cathode layer to a support membrane, preferably made of polytretrafluoroethylene, 2. drying of the coating obtained under (M1), 3. pressing the dried coating onto the electrolyte membrane at a temperature of 20 to 300 ° C., preferably 50 to 200 ° C., very particularly preferably 80 to 150 ° C., 4. Removing the support membrane, in particular by mechanical detachment, chemical dissolving, or pyrolizing 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 or fabric, 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 300 ° C., preferably 50 to 200 ° C., very particularly preferably 80 to 150 ° C. 52. The method according to any one of claims 48 or 49, wherein in step (B) in each case providing an agent for producing an anode layer and a cathode layer, the agent a) a metal catalyst salt, preferably hexachloroplatinic acid, b) 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, c) in step (D), an open-pore gas diffusion electrode, preferably an open-pore carbon paper, is pressed onto the catalyst or glued to the catalyst with an electrically conductive adhesive. 53. The method according to any one of claims 46 to 52, wherein the application of the agent for Production of an anode layer or cathode layer is carried out repeatedly and optionally a drying step, preferably at an elevated temperature in a range of 50 to 200 ° C, between repeating the Applying. 54. The method according to any one of claims 46 to 53, wherein the application of the agent for Production of an anode layer or cathode layer on one of a first roll unrolled flexible electrolyte membrane or flexible support membrane. 55. The method according to any one of claims 46 to 54, wherein the application of the agent for Production of an anode layer or cathode layer takes place continuously. 56. The method according to any one of claims 46 to 55, wherein the application of the agent for Production of an anode layer or cathode layer on a heated electrolyte or Support membrane is made. 57. The method according to any one of claims 46 to 56, wherein in step (D) to create a firm bond between the coatings and the electrolyte membrane on a Temperature of 50 to 300 ° C, preferably 50 to 200 ° C, most preferably 80 is heated to 150 ° C. 58. The method of claim 57, wherein by means of heated air, hot air, infrared radiation or microwave radiation is heated. 59. Medium comprising: 1. a condensable component which, after the condensation of an anode layer or a cathode layer of a membrane electrode assembly, imparts proton conductivity to a fuel cell, 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. 60. Composition according to claim 59, wherein the condensable component which, after the condensation of the anode layer or the cathode layer, gives proton conductivity is selected from A) hydrolyzable compounds 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 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 phosphorus or a hydrolysable 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. 61. Agent according to claim 59, in which the catalyst or the precursor compound of Catalyst includes platinum, palladium and / or ruthenium. 62. Agent according to one of claims 59 to 61, wherein the pore former is an organic and / or inorganic substance that is at a temperature between 50 and 300 ° C. and preferably decomposes between 100 and 200 ° C. 63. Agent according to claim 62, in which the inorganic pore former is ammonium carbonate or is ammonium bicarbonate. 64. Agent according to one of claims 59 to 63, wherein the catalyst support is electrical is conductive and preferably made of carbon black, graphite, carbon, carbon, activated carbon or Metal oxides exist. 65. Use of an electrolyte membrane according to one of claims 1 to 24 in one Fuel cell. 66. Use according to claim 65, wherein the fuel cell is a direct methanol Fuel cell or a reformate fuel cell. 67. Use of an electrolyte membrane according to one of claims 1 to 24 for the production a membrane electrode unit, a fuel cell, or a fuel cell stack. 68. Use of a membrane electrode assembly according to any one of claims 33 to 45 in a fuel cell. 69. Use according to claim 68, wherein the fuel cell is a direct methanol Fuel cell or a reformate fuel cell. 70. Fuel cell with an electrolyte membrane according to one of claims 1 to 24. 71. Fuel cell with a membrane electrode unit according to one of claims 33 to 45th 72. Mobile or stationary system with a membrane electrode assembly, one Fuel cell or a fuel cell stack containing an electrolyte membrane according to one of the Claims 1 to 24 or a membrane electrode assembly according to any one of claims 33 to 45. 73. Mobile or stationary system according to claim 72, characterized, that the mobile system is a vehicle and the stationary system is a house energy system.