Recycling of catalytic coated membrane components from fuel cells and reformers

Abstract

The present invention relates to a method for recycling a membrane electrode assembly from a fuel cell or a reformer. Further, the present invention relates to a polymer or a polymer solution obtained from the method according to the invention and to the use of the obtained polymer or polymer solution.

Description

[0001] RECYCLING OF CATALYTIC COATED MEMBRANE COMPONENTS FROM FUEL CELLS

[0002] AND REFORMERS

[0003] The present invention relates to a method for recycling a membrane electrode assembly from a fuel cell or a reformer. Further, the present invention relates to a polymer or a polymer solution obtained from the method according to the invention and to use of the obtained polymer or polymer solution.

[0004] A fuel cell is an electrochemical cell that converts the chemical energy of a fuel, such as hydrogen or lower hydrocarbons, and an oxidizing agent, such as oxygen, into electricity through a pair of redox reactions. Fuel cells play a crucial role in the supply of energy on the way of a more sustainable economy with a less severe ecological footprint. Fuels can be produced from regenerative energy, stored in large quantities and converted in a fuel cell to electrical power as needed. Fuel cells thus belong to the “green” technology for energy supply as long as the fuel is produced by green techniques.

[0005] Hydrogen as the fuel for fuel cells is becoming more and more important in the area of green technology. Excess electrical power may be used in so called reformers or electrolyzers to produce hydrogen as energy storing medium. The hydrogen may also be produced by reformers which transform natural gas, thus mostly methane, together with steam to hydrogen and carbon dioxide.

[0006] The hydrogen produced by electrolyzers or reformers can be used for operating fuel cells in vehicles or stationary power generators to generate electricity. The predominantly used fuel cell is the proton exchange membrane fuel cells (PEMFC). In these PEMFC as well as in reformers, catalysts - predominantly platinum and noble metals of the platinum group - are supported on carbon black materials which are deposited on membranes. These membranes are polymeric materials mostly comprising fluorinated polymers which are called ionomers.

[0007] Many attempts were pursued to recover the materials of fuel cells and reformers after the expiry of their life span. Most efforts concerned the recovery of the noble metals as they are most valuable materials in fuel cells. State of the art methods for the recovery of the noble metals are pyrometallurgical and hydrometallurgical methods. The pyrometallurgical method is conducted as follows: The combustion of the supporting film including the noble metal supported carbon produces an ash residue with the precious metals. This can be further processed into pure precious metal in the usual further treatment steps in precious metal refineries. The disadvantage is that the polymeric material is converted into carbon dioxide and other harmful substances including fluorine containing substances. In the hydrometallurgical method, alcohols are used for dissolving the membrane. The solids are separated from the solution by filtration and further processed pyrometallurgically. Such a method is disclosed in the US 2007 0292745 A1. However, here again a pyrometallurgical step is required.

[0008] The polymeric materials of the membranes have as well a high value. Furthermore, it is a contribution to environmental protection to fully recover the polymeric materials. The recovery of the materials for an arbitrary purpose is a first issue. However, the recovery of the polymeric materials such that they can be reused in rebuilt fuel cell membranes is a further and more interesting issue.

[0009] The invention’s underlaying problem relates to the provision of a method for recycling materials of fuel cells and reformers. The invention’s underlaying problem preferably refers to the provision of a method for recycling the noble metals and the polymeric materials of the membrane electrode assembly. A more preferred invention’s underlaying problem relates to the provision of a recycling method, which enables the reuse of the polymeric material for the purpose of rebuilding membranes for a fuel cell or a reformer. In particular, it is an object to provide the method as environmentally friendly as possible.

[0010] The invention’s underlaying problems are solved by the subject-matter of claim 1. Thus, according to a first aspect, the invention relates a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry; (b) heating the slurry to a temperature of 90°C to 160°C at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase.

[0011] By use of a short chain alkanol and under mild conditions of temperature and pressure, it is possible to dissolve ionomers and to obtain a solubilized polymeric phase and a solid phase. The obtained solution residue, i.e. the solid phase, contains the precious metals bound on carbon, which can be fed into the usual precious metal refining processes. In particular, the mild conditions together with the fluid containing the at least one Ci to Ce alkanol result in obtaining a liquid phase which contains the polymeric constituents which can be subjected to a work-up procedure to gain material which can be reused in a manufacturing of rebuilt fuel cells or reformers. The membrane electrode assembly used in the method of the invention is a membrane electrode assembly used in proton exchange membrane fuel cells (PEMFC).

[0012] Method steps (a) and (b) may be performed such that the membrane electrode assembly is firstly contacted with the fluid which has a higher temperature, wherein pressure is than exerted to the slurry. Further, method steps (a) and (b) can be performed simultaneously or subsequently one after the other.

[0013] Optionally, before method step (a) the membrane electrode assembly may be pre- processed. Preferably, before method step (a) the membrane electrode assembly may be mechanically treated, more preferred treated by a step of shredding the membrane electrode assembly. Further, before method step (a) the membrane electrode assembly may be chemically treated, more preferred with an acidic of basic composition. Such a treatment is beneficial to remove excess portions of adhesives or fatty substances. The optional steps taken before method step (a) are beneficial in order to isolate those parts of the fuel cell comprising the polymeric portions and the noble metal coated carbon material which are to be obtained from the method according to the invention. Therefore, according to a preferred embodiment, only those parts of the membrane electrode assembly are used which comprise the composite comprising the polymeric material of the membrane and the noble metal coated carbon material.

[0014] Performing method steps (a) and (b) results in obtaining a mixture of a solid phase and a liquid phase (step (c)). The solid phase predominantly contains the carbon supported noble metal catalyst. The liquid phase predominantly contains the solubilized polymeric constituents of the membrane electrode assembly. Step (d) of separating the solid phase and the liquid phase results in obtaining a phase which predominantly contains the polymeric constituents.

[0015] The polymer electrolyte membrane being the feedstock material of the method according to the invention comprises proton conducting polymer materials. These materials are also referred to below as ionomers. A tetrafluroethylene — flurovinyl ether copolymer with acid functions, particularly sulfuric acid groups, is preferably used. A material of this type is sold under the trade name Nation® by E.l. DuPont, for example. Other ionomer materials, particularly fluorine-free examples such as sulfonated polyether ketones or aryl ketones or polybenzimidazoles, can also be used, however.

[0016] The present invention aims at recovering the polymeric constituents comprising linear and / or branched perfluorinated copolymers. In a preferred embodiment of the present invention those membrane electrode assemblies are used in the recycling method which comprise these copolymers as the polymeric membrane material. In a further preferred embodiment, the membrane electrode assembly comprises a fluorocarbon-containing polymer essentially being devoid of cross-links. This means that the membrane electrode assembly is a thermoplastic material according to this preferred embodiment.

[0017] According to a preferred embodiment, the membrane electrode assembly comprises a fluorocarbon-containing polymer essentially being devoid of cross-links. The term “essentially” in this respect means that the fluorocarbon-containing polymer is not a network or a thermoset material. According to a more preferred embodiment, the membrane electrode assembly comprises a fluorocarbon-containing polymer is devoid of cross-links.

[0018] According to preferred embodiments, the Ci to Ce alkanol is represented by methanol, ethanol, propanol and / or isopropanol, more preferred the Ci to Ce alkanol is represented by ethanol.

[0019] According to an embodiment, the fluid comprises the Ci to Ce alkanol and water. Preferably, the fluid consists of the Ci to Ce alkanol and water, wherein preferably the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, more preferred from 90 / 10 to 55 / 45, even more preferred from 85 / 15 to 75 / 25. The term “ratio of x / y” means ratio of x versus y in terms of the weight percentages (wt.-%). It is understood that the fluid may consist of ethanol and water, wherein preferably the ratio of ethanol to water (ethanol / water) is from 95 / 5 to 50 / 50, more preferred from 90 / 10 to 55 / 45, even more preferred from 85 / 15 to 75 / 25. In a further preferred embodiment, the mixtures of alkanol and water may comprise further constituents.

[0020] The water is preferably demineralized water. In a most preferred embodiment, the electrical conductivity of the water amounts to 50pS / cm at most. Therefore, in a preferred embodiment, the water used in the fluid is essentially free of salt. The term “essentially” means that no salt constituents are added and the electrolytes are removed from taped water by known means. It is important to use mild conditions in the method according to the invention in order to keep the polymeric material non-destructed. According to a preferred embodiment, the method is conducted in that step (b) heating the slurry is performed at a temperature of 110°C to 150°C, preferably 125°C to 145°C. Further, the pressure is important. According to a preferred embodiment, the pressure amounts to 5 bar to 15 bar, preferably 8 to 10 bar.

[0021] Mild conditions also refer to the way of contacting the membrane electrode assembly with the fluid as well as the duration of method steps (a) and (b). According to a preferred embodiment, step (b) is performed under mixing. According to a further preferred embodiment, step (b) is performed for a duration of 1 minute to 120 minutes, preferably 5 minutes to 60 minutes; more preferred 15 minutes to 30 minutes.

[0022] It has surprisingly been found that the way of conducting step (d), i.e. the step of separating the two phases, is important. According to a preferred embodiment, step (d) is performed by centrifugation, sedimentation, decantation or filtration. Performing step (d) by a regular filtration only is the least preferred.

[0023] It was surprisingly found that the separation by centrifugation gave the best performing polymeric material when being reused for fuel cells or reformers. The reason as to why this separation technique is the most beneficial is not immediately conceivable. Without being bound to a specific theory, it could possibly be assumed that the centrifugation of the dispersion comprising the solid phase and the liquid phase results in a separation of very small polymeric aggregates. In a regular state of the art filtration, such material is possibly not be separated. It was the most preferred object of the present invention to provide a method where the polymeric material of the membrane electrode assembly of a fuel cell or a reformer can be recycled such that the polymeric material can be reused in a rebuilt fuel cell or reformer.

[0024] In an alternative preferred embodiment, step (d) is performed by centrifugation followed by filtration. The filtration in this preferred embodiment is most preferred a vacuum filtration. The two fractions are, however, preferably separated by means of a centrifuge.

[0025] According to a preferred embodiment, the method is characterized in that it further comprises the steps of (d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution; and (e-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid, wherein preferably the at least partially separating the fluid from the polymer solution is performed by evaporating at least part of the fluid.

[0026] According to further embodiments, it is preferred that the above method step (d) of separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution or step (e-1) are alternatively performed in the method according to the invention.

[0027] Method step (d) according to this preferred embodiment results in obtaining a liquid phase being a polymer solution. This polymer solution contains the polymer which constituted the polymer film of the membrane electrode assembly. Due to the fact that the membrane electrode assembly is subjected to the treatment steps according to the invention, it may be possible that the polymer received from the liquid phase distinguishes from the originally used polymer constituting the polymer film of the membrane electrode assembly.

[0028] Therefore, the polymer obtained from the liquid phase is designated as “recovered polymer”. In a very preferred embodiment, between step (d) and step (e-1), a further step is performed, which further step comprises an ultra-filtration and / or dialysis of the liquid phase being the polymer solution. This further step may be performed to separate low molecular weigh components from the polymer solution.

[0029] However, it might be possible that the “recovered polymer” represents the polymer of the polymer film of the membrane electrode assembly. In any case, the recovered polymer is ready for being reused for a manufacturing process of a membrane electrode assembly.

[0030] According to a preferred embodiment, the method further comprises the step of (f-1) reusing the recovered fluid in method step (a). Preferably, method step (f-1) is performed after method step (e-1). As will be understood by a skilled person, the advantage of this method step refers to both economic and environmental aspects since it reduces the consumption of hydrocarbons.

[0031] In an alternative or additional preferred embodiment of the invention, the solid phase is subjected to a work-up procedure in order to obtain recovered noble metal. According to this preferred embodiment, the method comprises the steps of (d’) separating the solid phase and the liquid phase to receive the solid phase comprising a recovered supported noble metal catalyst; and (e-2) subjecting the recovered supported noble metal catalyst to a refining method to recover the noble metal. The step (d’) represents the alternative or additional step compared to step (d), which concerns the recovery of the polymeric material.

[0032] The supported noble metal catalyst may comprise platinum, palladium, rhodium, iridium, or any alloy thereof being supported on carbon particles. In the membrane electrode assembly, the composite of said metals and carbon particles is again supported on at least one side of the polymer film. In said alternative or additional preferred embodiment of the invention, said noble metals are recovered for any purpose or for the purpose of reusing it in rebuilding membrane electrode assemblies.

[0033] If in the present application, it is referred to a “membrane electrode assembly of a fuel cell”, the membrane electrode assembly of a reformer is meant as well.

[0034] The invention’s underlaying problems are further solved by the subject-matter of claim 11. Thus, according to a second aspect, the invention relates to a polymer solution obtained from a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry; (b) heating the slurry at a temperature of 90°C to 160°C and at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution.

[0035] As an alternative second aspect, the invention relates to a polymer obtained from a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry; (b) heating the slurry at a temperature of 90°C to 160°C and at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution. Subject of the second aspect of the present invention is the polymer and the polymer solution obtained from the method of recycling a membrane electrode assembly. Although it is the polymer without the fluid which is used for rebuilding a membrane electrode assembly, it may be beneficial to store the polymer together with the fluid, i.e. in form of its solution. Firstly, the polymer solution can be subjected to further purification processes like e.g. a dialysis, and further the solution is not to such an extent exerted to changes in terms of the polymer’s chemical or structural nature. With regard to the alternative aiming at the polymer solution, it is obvious for a skilled person that the polymer may be obtained from the polymer solution by separating the fluid from the polymer by evaporation of the fluid.

[0036] In a preferred embodiment, the invention relates to a polymer obtained from a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry; (b) heating the slurry at a temperature of 90°C to 160°C and at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; (d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution; and (e-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid.

[0037] In an alternative preferred embodiment, the method further comprises the step of (e’-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid, wherein the at least partially separating the fluid from the polymer solution is performed by ultrafiltering or dialyzing the polymer solution prior to evaporating at least part of the fluid. This alternative preferred embodiment assists in getting rid of low molecular constituents from the polymer solution.

[0038] The invention’s underlaying problems are further solved by the subject-matter of claim 15. Thus, according to a third aspect, the invention relates to the use of a polymer or a polymer solution according to the invention for manufacturing a membrane electrode assembly for a fuel cell or a reformer. Features relating to preferred embodiments of the first aspect of the present invention, which are solely disclosed relating to the first aspect of the invention represent preferred embodiments of the second and third embodiment as well.

[0039] The enclosed figure as a part of this description illustrates an embodiment of the invention and together with the description serves to explain the principles of the invention. The figure is enclosed for this illustrative purpose, it is not to be understood as limiting the invention’s scope.

[0040] Fig. 1 illustrates the process for recycling catalytic coated membrane (CCM) components from fuel cells and reformers in accordance with the present invention as non-limiting aspects of the present invention.

[0041] In a first stage the membrane electrode assembly is mechanically treated in a shredder 10 in order to reduce the particle size of the material subjected to the method according to the invention. On a line or more particular a conveyor belt 21, the prepared shredded particles of the membrane electrode assembly are fed to the low-pressure reactor 12. Therein, the above method steps (a) to (c) may be conducted. A basic dispersion is obtained which is fed via line 23 to the centrifuge 14. As described above, the separation of the solid phase and the liquid phase by a centrifuge has figured out to be most beneficial for solving the invention’s underlaying problems. In the exemplary embodiment illustrated in Fig. 1 , the liquid fraction is fed via line 25 to the vacuum filter 16, in which the liquid fraction is subjected to a vacuum filtration. The liquid outcome of this method step is led out and represents to solution comprising the polymeric material. The product solution can be stored. When being ready for use in the rebuilding of a membrane electrode assembly, the fluid can be separated in the rotary evaporator 18. The product is the recovered polymeric material, which can be reused for rebuilding a further membrane electrode assembly. The separated fluid from the rotary evaporator 18 is fed via line 31 to the low-pressure reactor for the reuse as a fluid in a further method of recycling a membrane electrode assembly. The solids containing fraction is led out of the centrifuge via device 27. This fraction is subjected to a noble metal refining in order to obtain recovered noble metals. In the following, exemplary embodiments (A) to (H) are disclosed which represent particularly preferred embodiments.

[0042] (A)

[0043] Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one of methanol, ethanol, propanol or isopropanol to obtain a slurry; (b) heating the slurry to a temperature of 90°C to 160°C at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase.

[0044] (B)

[0045] Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid comprising at least one Ci to Ce alkanol and water, wherein the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, more preferred from 90 / 10 to 55 / 45, even more preferred from 85 / 15 to 75 / 25, to obtain a slurry; (b) heating the slurry to a temperature of 90°C to 160°C at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase.

[0046] (C)

[0047] Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid comprising at least one Ci to Ce alkanol and water, wherein the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, preferably from 90 / 10 to 55 / 45, more preferred from 85 / 15 to 75 / 25, to obtain a slurry; (b) heating the slurry to a temperature of 125°C to 145°C at a pressure of 8 bar to 10 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase. (D)

[0048] Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one of methanol, ethanol, propanol or isopropanol to obtain a slurry; (b) heating the slurry to a temperature of 90°C to 160°C at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase by centrifugation.

[0049] (E)

[0050] Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid comprising at least one Ci to Ce alkanol and water, wherein the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, preferably from 90 / 10 to 55 / 45, more preferred from 85 / 15 to 75 / 25, to obtain a slurry; (b) heating the slurry to a temperature of 125°C to 145°C at a pressure of 8 bar to 10 bar; (c) receiving a mixture of a solid phase and a liquid phase; and (d) separating the solid phase and the liquid phase by centrifugation.

[0051] (F)

[0052] Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalysts coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid comprising at least one Ci to Ce alkanol and water, wherein the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, preferably from 90 / 10 to 55 / 45, more preferred from 85 / 15 to 75 / 25, to obtain a slurry; (b) heating the slurry to a temperature of 125°C to 145°C at a pressure of 8 bar to 10 bar; (c) receiving a mixture of a solid phase and a liquid phase; (d) separating the solid phase and the liquid phase by centrifugation; and (e-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid, wherein preferably the at least partially separating the fluid from the polymer solution is performed by evaporating at least part of the fluid. (G)

[0053] Polymer or polymer solution obtained from a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry; (b) heating the slurry at a temperature of 90°C to 160°C and at a pressure of 2 bar to 25 bar; (c) receiving a mixture of a solid phase and a liquid phase; (d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution by centrifugation; and (e) separating the fluid from the liquid phase to obtain the recovered polymeric material.

[0054] (H)

[0055] Polymer or polymer solution obtained from a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of (a) contacting the membrane electrode assembly with a fluid comprising at least one Ci to Ce alkanol and water, wherein the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, preferably from 90 / 10 to 55 / 45, more preferred from 85 / 15 to 75 / 25, to obtain a slurry; (b) heating the slurry to a temperature of 125°C to 145°C at a pressure of 8 bar to 10 bar; (c) receiving a mixture of a solid phase and a liquid phase; (d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution by centrifugation; and (e) separating the fluid from the liquid phase to obtain the recovered polymeric material.

Claims

Claims1. Method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of(a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry;(b) heating the slurry at a temperature of 90°C to 160°C and at a pressure of 2 bar to 25 bar;(c) receiving a mixture of a solid phase and a liquid phase; and(d) separating the solid phase and the liquid phase.

2. Method according to claim 1, characterized in that the Ci to Ce alkanol is Ethanol; or characterized in that the fluid consists of the Ci to Ce alkanol and water, wherein preferably the ratio of the Ci to Ce alkanol to water (alkanol / water) is from 95 / 5 to 50 / 50, more preferred from 90 / 10 to 55 / 45, even more preferred from 85 / 15 to 75 / 25.

3. Method according to claim 1 or claim 2, characterized in that the membrane electrode assembly comprises a fluorocarbon-containing polymer essentially being devoid of cross-links.

4. Method according to claim 1 or claim 3, characterized in that step (b) heating the slurry is performed at a temperature of 110°C to 150°C, preferably 125°C to 145°C; and / or the pressure amounts to 5 bar to 15 bar, preferably 8 to 10 bar.

5. Method according to any one of claims 1 to 4, characterized in that step (b) is performed under mixing; or characterized in that step (b) is performed for a duration of 1 minute to 120 minutes, preferably 5 minutes to 60 minutes; more preferred 15 minutes to 30 minutes.

6. Method according to any one of claims 1 to 5, characterized in that step (d) is performed by centrifugation, sedimentation, decantation or filtration, preferably centrifugation.

7. Method according to any one of claims 1 to 5, characterized in that step (d) is performed by centrifugation followed by filtration.

8. Method according to any one of claims 1 to 7, characterized in that the method further comprises the steps of(d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution; and(e-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid, wherein preferably the at least partially separating the fluid from the polymer solution is performed by evaporating at least part of the fluid.

9. Method according to any one of claims 1 to 8, characterized in that the method comprises the step of(f-1) reusing the recovered fluid in method step (a).

10. Method according to any one of claims 1 to 7, characterized in that the method comprises the steps of(d’) separating the solid phase and the liquid phase to receive the solid phase comprising a recovered supported noble metal catalyst; and(e-2) subjecting the recovered supported noble metal catalyst to a refining method to recover the noble metal.

11. A polymer or a polymer solution obtained from a method for recycling a membrane electrode assembly from a fuel cell or a reformer, wherein the membrane electrode assembly comprises a polymer film and a supported noble metal catalyst coated on at least one side of the polymer film, wherein the method comprises the steps of(a) contacting the membrane electrode assembly with a fluid containing at least one Ci to Ce alkanol to obtain a slurry;(b) heating the slurry at a temperature of 90°C to 160°C and at a pressure of 2 bar to 25 bar;(c) receiving a mixture of a solid phase and a liquid phase; and(d) separating the solid phase and the liquid phase to receive the liquid phase being a polymer solution.

12. Polymer or polymer solution according to claim 11, characterized in the method further comprises the step of(e-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid.

13. Polymer or polymer solution according to claim 11, characterized in the method further comprises the step of(e-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid, wherein the at least partially separating the fluid from the polymer solution is performed by evaporating at least part of the fluid.

14. Polymer or polymer solution according to claim 11, characterized in the method further comprises the step of(e’-1) at least partially separating the fluid from the polymer solution to obtain a recovered polymer and a recovered fluid, wherein the at least partially separating the fluid from the polymer solution is performed by ultrafiltering or dialyzing the polymer solution prior to evaporating at least part of the fluid.

15. Use of a polymer or a polymer solution according to any one of claims 11 to 14 for manufacturing a membrane electrode assembly for a fuel cell or a reformer.

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