Arrangement consisting of an electrolysis cell component and a catalyst layer, method for manufacturing the arrangement and electrolysis device

Abstract

An arrangement comprising an electrolysis cell component of an electrolysis cell of an electrolysis device and an anode-side catalyst layer (15) arranged on the electrolysis cell component, wherein the anode-side catalyst layer (15) comprises first particles (19) of platinum (Pt), second particles (20) of iridium (Ir) and / or of ruthenium (Ru) and / or of iridium oxide (IrOX) and / or of ruthenium oxide (RuOX) and / or of mixed phases (IrRuOX) of these oxides and an ionomer (21), and wherein the first particles (19) and the second particles (20) are bonded to each other exclusively via the ionomer (21).

Description

[0001] The invention relates to an arrangement comprising an electrolysis cell component of an electrolysis cell of an electrolysis device and a catalyst layer arranged on the anode side of the electrolysis cell component. The invention further relates to a method for manufacturing such an arrangement and an electrolysis device with such an arrangement.

[0002] DE 10 2017 108 413 A1 discloses an electrochemical device designed as an electrolysis apparatus with a cell stack consisting of several cell stack elements or several electrolysis cell components, which together form several electrolysis cells. Furthermore, the electrolysis device known from this prior art has a force application unit by which a force can be exerted on the cell stack to compress the cell stack elements or electrolysis cell components of the cell stack in a fluid-tight manner. One of the electrolysis cell components of an electrolysis cell is a proton exchange membrane. The proton exchange membrane is arranged between two bipolar plates of the electrolysis cell, with fluid guide elements of the electrolysis cell being arranged between each of the bipolar plates and the proton exchange membrane. The bipolar plates and the fluid guide elements constitute further electrolysis cell components.The proton exchange membrane preferably carries a catalyst layer on both sides, namely an anode-side catalyst layer on one side and a cathode-side catalyst layer on the other. A proton exchange membrane coated with catalyst layers on both sides is also referred to as a catalyst-coated membrane or CCM. Alternatively, the catalyst layers of an electrolysis cell can also be arranged on the fluid guide elements of the electrolysis cell.

[0003] In order for an electrolysis cell, and thus an electrolysis device containing the electrolysis cell, to have high efficiency, it is necessary that the catalyst layer on the anode side, in particular, has high electrical conductivity.

[0004] CN 113 430 555 B discloses a catalyst layer comprising iridium oxide and platinum, wherein the iridium oxide and platinum are chemically bonded, i.e., arranged in a common crystal lattice.

[0005] Starting from this, the present invention is based on the objective of creating a novel arrangement comprising an electrolysis cell component of an electrolysis cell of an electrolysis device and an anode-side catalyst layer arranged on the electrolysis cell component, a method for producing such an arrangement and an electrolysis device with such an arrangement.

[0006] This problem is solved by an arrangement according to claim 1, an electrolysis device according to claim 11 and a method according to claim 12.

[0007] According to the invention, the anode-side catalyst layer comprises first particles made of platinum (Pt), second particles made of iridium (Ir) and / or ruthenium (Ru) and / or iridium oxide (IrOX) and / or ruthenium oxide (RuOX) and / or mixed phases (IrRuOX) of these oxides, and an ionomer. The first and second particles are bonded to each other exclusively via the ionomer. The first and second particles are present in the anode-side catalyst layer without any chemical bond between them.

[0008] It has surprisingly been found that an anode-side catalyst layer for an electrolysis cell, in which the first and second particles are not chemically bonded but are connected solely via the ionomer, exhibits high electrical conductivity, resulting in high efficiency. Furthermore, such an anode-side catalyst layer can be easily produced.

[0009] Preferably, the anode-side catalyst layer has a thickness between 2 µm and 20 µm, particularly a thickness between 4 µm and 5 µm, wherein the first particles and the second particles preferably have a particle size between 0.1 µm and 10 µm, particularly a particle size between 0.8 µm and 1.2 µm. This is particularly preferred to provide a high-efficiency anode-side catalyst layer.

[0010] Preferably, the volume ratio V2:V1 between the volume V2 of all second particles and the volume V1 of all first particles is between 1:1 and 1:2.5, particularly 1:2. This is also particularly preferred in order to provide an anode-side catalyst layer of a high-efficiency electrolysis cell.

[0011] Preferably, the electrolysis cell component is a proton exchange membrane, in particular a PFSA-based polymer membrane. The anode-side catalyst layer is especially preferably applied to a proton exchange membrane to provide a catalyst-coated membrane with high efficiency.

[0012] Preferred embodiments of the invention are set forth in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1. A diagram of an electrolysis cell, Fig. 2 an excerpt from Fig. 1 in the area of ​​an anode-side catalyst layer.

[0013] Fig. Figure 1 shows a section of an electrolysis device in the area of ​​an electrolysis cell 10.

[0014] The electrolysis cell 10 comprises two bipolar plates 11, 12 as electrolysis cell components, with a catalyst-coated membrane 13 arranged between the bipolar plates 11, 12 and a fluid conduction structure 17, 18 arranged between the catalyst-coated membrane 13 and each of the bipolar plates 11, 12 as further electrolysis cell components. The electrolysis cell 10 is connected to a current or voltage source via the bipolar plates 11, 12, such that one of the bipolar plates 12 serves as the anode and the other of the bipolar plates 11 as the cathode.

[0015] A fluid conduction structure is a component that enables the transport of media from inlets and outlets located in or on the bipolar plates to the catalyst-coated membrane. In addition to media transport, another requirement for fluid conduction structures is good electrical conductivity. Electrical voltage induced across the end plates of an electrolysis cell stack (the electrolysis device) must be conducted through all electrolysis cells and each electrolysis cell component. Therefore, a good fluid conduction structure must contain as much conductive material as possible for good conductivity (i.e., few pores or fluid channels), while for good media transport, it should contain as little material as possible (i.e., many pores or fluid channels). A suitable fluid conduction structure could be a titanium felt or titanium sinter product with macroporous pore sizes (macroporous = pores > 50 nm).

[0016] The catalyst-coated membrane 13 includes a proton exchange membrane 14 as a further electrolysis cell component, which carries a porous catalyst layer 15 or 16 on each side. The porous catalyst layer 15 is also referred to as the cathode-side catalyst layer, and the porous catalyst layer 16 as the anode-side catalyst layer. The catalyst layers 15 and 16 must be porous to allow the transport of reactants (water, hydrogen, oxygen) to and from the membrane 13.

[0017] In the illustrated embodiment, the catalyst layers 15, 16 are arranged on the proton exchange membrane 14 and thus form the catalyst-coated membrane 13. In contrast, it is also possible for the cathode-side catalyst layer 15 to be arranged on the fluid conduction structure 17 and the anode-side catalyst layer 16 to be arranged on the fluid conduction structure 18 and to be metallurgically bonded.

[0018] The anode-side catalyst layer 16 has at least first particles 19, second particles 20 and an ionomer 21.

[0019] The first particles, number 19, are particles made of platinum (Pt).

[0020] The second set of particles 20 consists of iridium particles (Ir) and / or ruthenium particles (Ru) and / or iridium oxide particles (IrO). X and / or particles made of ruthenium oxide RuO X and / or particles from mixed phases of these oxides, i.e., from mixed phases IrRuOX of iridium oxide and ruthenium oxide.

[0021] The first particles 19 and the second particles 20 are bonded to each other exclusively via the ionomer 21, so that the first particles 19 and the second particles 20 are present in the anode-side catalyst layer 16 without any chemical bond between them. In other words, there is no direct chemical bond between the first and second particles. The first and second particles are bonded indirectly via the ionomer.

[0022] It is a finding of the invention that an anode-side catalyst layer 16, in which the first particles 19 are made of platinum and the second particles 20 are made of iridium and / or ruthenium and / or iridium oxide and / or ruthenium oxide and / or mixed phases of these oxides, which are not chemically bonded to each other but are only bonded to each other via an ionomer 21, has excellent properties with regard to the electrical conductivity of electrons and protons, so that high efficiency can be provided.

[0023] Preferably, the anode-side catalyst layer 16 has a thickness between 2 µm and 20 µm, more preferably a thickness between 4 µm and 10 µm or a thickness between 4 µm and 5 µm. The first particles 19 and the second particles 20 have a particle size between 0.1 µm and 10 µm, more preferably a particle size between 0.8 µm and 1.2 µm.

[0024] To provide an anode-side catalyst layer 16 with high electrical conductivity and thus high efficiency, it is particularly preferred if the volume ratio V2:V1 between the volume V2 of all second particles 20 and the volume V1 of all first particles 19 is between 1:1 and 1:2.5. Preferably, the volume ratio V2:V1 is 1:2.

[0025] To provide an anode-side catalyst layer 16 with good electron and proton conductivity properties and thus high efficiency, it is advantageous if the mass ratio m1:m2 between the mass m1 of all first and second particles 19 and 20 and the mass m2 of the ionomer 21 is between 95:5 and 65:35. It is particularly preferred if the anode-side catalyst layer 16 is applied to a proton exchange membrane 14, thus forming part of a catalyst-coated membrane 13.

[0026] The proton exchange membrane 14 is preferably a PFSA-based polymer membrane, wherein the PFSA can have side chains of different lengths and equivalent weights.

[0027] Preferably, the proton exchange membrane 14 has a thickness between 50 µm and 150 µm, preferably a thickness between 75 µm and 125 µm.

[0028] The anode-side catalyst layer 16 can also be part of the fluid conduction structure 18, i.e., firmly connected to the fluid conduction structure. In the present embodiment, however, the catalyst layer 16 is firmly connected to the membrane 14. Contact with the fluid conduction structure is achieved via the aforementioned compression forces of the force application unit. However, a metallurgical bond between the catalyst layer 16 and the fluid conduction structure does not exist in the illustrated embodiment.

[0029] The invention further relates to an electrolysis device with a cell stack consisting of several electrolysis cell components, forming multiple electrolysis cells. Such an electrolysis device further comprises a force application unit with end plates, wherein the electrolysis cell components are arranged and pressed between the end plates. Each electrolysis cell has an anode-side catalyst layer 16, which is arranged either on a proton exchange membrane 14 or on a fluid conduction structure 18.

[0030] The invention further relates to a method for providing an arrangement comprising an electrolysis cell component and an anode-side catalyst layer 16. As already described, the arrangement can comprise the proton exchange membrane 14 or the fluid conduction structure 18 as the electrolysis cell component, wherein the anode-side catalyst layer 16 is applied to the respective electrolysis cell component.

[0031] To provide an assembly consisting of an electrolysis cell component and the anode-side catalyst layer 16, an ink is first provided, comprising a solvent, the first particles 19, the second particles 20, and the ionomer 21. The provided ink is applied to a support film, preferably a PET-reinforced ETFE support film, and spread over it with a doctor blade. The ink is dried on the support film, forming the anode-side catalyst layer 16. During drying, the solvent evaporates, and the remaining components form the continuous catalyst layer 16. Subsequently, the anode-side catalyst layer 16 is transferred from the support film to the respective electrolysis cell component.

[0032] Alternatively, a direct coating process can be used. In a direct coating process, the ink is applied directly to the electrolysis cell component, especially the membrane, and then dried. This enables industrial production. Examples of possible direct coating processes include screen and inkjet printing, slot-die coating, and doctor blade coating.

[0033] To provide the ink comprising the solvent, the first particles 19, the second particles 20 and the ionomer 21, it is preferably carried out by providing two inks, namely a first ink comprising the solvent, the first particles 19 and the ionomer 21, and a second ink comprising the solvent, the second particles 20 and the ionomer 21.

[0034] The first ink and the second ink are mixed in such a way that the ink to be applied to the carrier film has the desired volume ratio V2:V1 between the volume V2 of all second particles 20 and the volume V1 of all first particles 19.

[0035] Alternatively, the first and second particles can also be mixed directly with the solvent and the ionomer to form a common ink solution.

[0036] Advantageous inks contain solids and solvents in suitable mass ratios. A suitable composition can be determined in the laboratory through simple experiments, ensuring the ink exhibits the desired coating and drying properties. Further information can be found in the relevant literature.

[0037] The ink, which comprises the solvent, the first particles 19, the second particles 29 and the ionomer 21, is preferably applied by squeegeeing the ink onto the carrier film.

[0038] After the ink is applied to the carrier film, it is dried on the carrier film, preferably in air at room temperature. Other drying methods, particularly for industrial applications, are possible. Convection drying, for example, is a suitable drying method.

[0039] After the ink has dried on the carrier film, the anode-side catalyst layer 16 is present. Cutouts with defined dimensions can be produced from the carrier film and the anode-side catalyst layer 16 arranged on it. These cutouts are subsequently used to transfer the anode-side catalyst layer 16 from the carrier film to the proton exchange membrane 14. Alternative deposition methods (direct coating) have already been mentioned above.

[0040] To transfer the anode-side catalyst layer 16 from the carrier film to the proton exchange membrane 14, a decal process or decal transfer is preferably used. In this process, a defined pressure is applied to the carrier film at a defined temperature to detach the anode-side catalyst layer 16 from the carrier film and adhere it to the proton exchange membrane 14. For this purpose, the proton exchange membrane 14, together with the carrier film containing the anode-side catalyst layer 16, can be moved through pressure rollers or joined together by hot pressing. Suitable manufacturing and joining conditions depend on the specific application and must be determined through testing. In the case of a direct coating process, the joining step (pressure rollers, hot pressing) can be omitted. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 108 413 A1

[0002] CN 113 430 555 B

[0004]

Claims

[1] Arrangement comprising an electrolysis cell component of an electrolysis cell of an electrolysis device and an anode-side catalyst layer (16) arranged on the electrolysis cell component, characterized by , that the anode-side catalyst layer (16) first particles (19) of platinum (Pt), second particles (20) of iridium (Ir) and / or of ruthenium (Ru) and / or of iridium oxide (IrO) X ) and / or from ruthenium oxide (RuO₂) X ) and / or from mixed phases (IrRuO X ) this oxide and an ionomer (21) wherein the first particles (19) and the second particles (20) are bonded to each other exclusively via the ionomer (21). [2] Arrangement according to claim 1, characterized by , that the first particles (19) and the second particles (20) are present in the anode-side catalyst layer (16) without any chemical connection between the first particles (19) and the second particles (20). [3] Arrangement according to claim 1 or 2, characterized by , that the anode-side catalyst layer (16) has a thickness between 2 µm and 20 µm, preferably a thickness between 4 µm and 5 µm. [4] Arrangement according to any one of claims 1 to 3, characterized by , that the first particles (19) and the second particles (20) have a particle size between 0.1 µm and 10 µm, preferably a particle size between 0.8 µm and 1.2 µm. [5] Arrangement according to any one of claims 1 to 4, characterized by that the volume ratio V2:V1 between the volume V2 of all second particles (20) and the volume V1 of all first particles (19) is between 1:1 and 1:2.5, preferably 1:

2. [6] Arrangement according to any one of claims 1 to 5, characterized by , that the mass ratio m1:m2 between the mass m1 of all first (19) and second particles (20) and the mass m2 of the ionomer (21) is between 95:5 and 65:

35. [7] Arrangement according to any one of claims 1 to 6, characterized by , that the electrolysis cell component is a proton exchange membrane (14). [8] Arrangement according to claim 7, characterized by , that the proton exchange membrane (14) is a PFSA-based polymer membrane. [9] Arrangement according to claim 7 or 8, characterized by , that the proton exchange membrane (14) has a thickness between 50 µm and 150 µm. [10] Arrangement according to any one of claims 1 to 6, characterized by , that the electrolysis cell component is a fluid conducting structure (18). [11] Electrolysis device, with a cell stack consisting of several electrolysis cell components that form multiple electrolysis cells, with a force application unit having end plates, wherein the cell stack is arranged and pressed between the end plates from the cell stack elements, characterized by , that Each electrolysis cell comprises an electrolysis cell component according to one of claims 1 to 10. [12] Method for manufacturing an arrangement according to any one of claims 1 to 10, characterized by the following steps: Providing an ink comprising a solvent, the first particles (19), the second particles (20) and the ionomer (21), Applying, preferably with a squeegee, the provided ink onto a carrier film, Drying of the ink on the carrier film, forming the anode-side catalyst layer (16), Transfer of the anode-side catalyst layer (16) from the carrier film to the electrolysis cell component, or direct application of the ink to the electrolysis cell component using a direct application process and subsequent drying on the electrolysis cell component. [13] Method according to claim 12, characterized by , that a first ink is provided which has a solvent, the first particles (19) and the ionomer (21), a second ink is provided which includes a solvent, the second particles (20) and the ionomer (21), The first ink and the second ink are mixed in such a way that the ink to be applied has a volume ratio V2:V1 between the volume V2 of all second particles and the volume V1 of all first particles between 1:1 and 1:2.5, preferably 1:

2. [14] Method according to claim 12 or 13, characterized by , that the anode-side catalyst layer (16) is transferred from the carrier film to the electrolysis cell component using a decal process.

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