Membrane-electrode assembly and water electrolysis cell

Abstract

The invention relates to a membrane-electrode assembly (1) comprising a cathode (2), an anode (3), and a proton-conductive membrane (4), wherein the proton-conductive membrane (4) is arranged between the cathode (2) and the anode (3), wherein the anode (3) comprises a noble-metal-containing oxygen evolution catalyst (5), an electrically conductive platinum component (6), a ceramic material (7), and a proton-conductive polymer (8), wherein the areal loading of the oxygen evolution catalyst (5), based on the noble-metal content of the oxygen evolution catalyst (5), is from 0.10 mg / cm² to 0.28 mg / cm².

Description

[0001] HOEFER & PARTNER

[0002]

[0003] March 20, 2026 Applicant:

[0004] Greenerity GmbH

[0005] Industrial Area South E11

[0006] 63755 Alzenau

[0007] Membrane electrode arrangement and water electrolysis cell

[0008] Description

[0009] The invention relates to a highly efficient membrane electrode arrangement with very good long-term stability and a water electrolysis cell which, due to the use of the membrane electrode arrangement, is also characterized by very good performance and high long-term stability.

[0010] To improve the efficiency of membrane electrode assemblies (MEAs), there is a general tendency to reduce the catalyst content in the electrodes. However, very low catalyst concentrations, for example in the anode of an MEA, result in a reduced anode layer thickness due to the low catalyst loading. This, in turn, negatively impacts the efficiency of the MEA, as the reactants flowing through the anode in the layer thickness direction have fewer opportunities for catalytic reaction, and the transverse electrical conductivity in the layer suffers. The reduced layer thickness also negatively affects the long-term stability of the electrodes.

[0011] CN 2023 10668243 A aims to provide an anode catalyst layer that forms a uniform film and delivers high performance even with low iridium loading. To achieve this, the anode catalyst layer incorporates an iridium-based catalyst and conductive particles containing, for example, iridium black, silver, gold, or nickel. A disadvantage of this prior art is that the performance of the MEA is still too low for standard applications.

[0012] EP 3748039 A1 also addresses the provision of a polymer membrane-based electrolysis cell that exhibits high performance despite a lower catalyst loading and is further characterized by high stability and low manufacturing costs. EP 3748039 A1 solves this problem through a specific layer arrangement, in which, in addition to an anode and a cathode, transport layers near the anode and near the cathode are provided, and an intermediate layer comprising electrically conductive nanofibers is located between a transport layer and the anode or the cathode. Furthermore, at least one of the catalytically active layers comprises a mixture of catalytically active nanoparticles and electrically conductive nanofibers. Alternatively, one of the transport layers can also comprise electrically conductive nanofibers.A disadvantage of this state of the art is that a multilayer structure must be produced, which entails additional production effort, also in terms of cost. If only the performance of a single catalytically active layer with catalytically active nanoparticles and electrically conductive nanofibers is achieved, the layer thickness is too thin and does not achieve sufficient long-term stability, while performance is rather mediocre.

[0013] Based on this prior art, the object of the present invention is to provide a MEA that, at low catalyst loading, is characterized by very good performance, i.e., low cell voltage, and furthermore by very good long-term stability. In addition, it is an object of the present invention to provide a water electrolysis cell that, due to the use of the MEA according to the invention, also exhibits very good performance and high long-term stability.

[0014] These problems are solved by the features of the independent claims. The dependent claims contain advantageous further developments and embodiments of the invention.

[0015] Accordingly, the problem is solved by a MEA comprising a cathode, an anode, and a proton-conducting membrane situated between these electrodes, the anode being specifically designed as detailed below. The MEA is not limited in its specific design but is particularly suitable for water electrolysis and is preferably used for this purpose.

[0016] The anode comprises a precious metal-containing oxygen evolution catalyst (hereinafter referred to as OER). The areal weight of the OER is 0.10 mg / cm². 2 up to 0.28 mg / cm² 2The basis weight refers to the precious metal of the OER. This means that if, for example, a precious metal compound, such as an oxide of a precious metal, is used as the OER, the amount of OER refers to the precious metal contained in the oxide. A conversion can be easily performed using the amount of substance and the molar weight of the OER. As the English explanation already explains, the OER serves to generate oxygen from water. As can be seen from this, the precious metal content in the anode is extremely low, so that a high efficiency of the MEA can be achieved from an economic point of view. It goes without saying that two or more OERs can also be used in combination. However, if two or more OERs are used in combination according to the invention, the basis weight refers to the total amount of all OERs in the anode.

[0017] To improve the performance of the MEA, the OER is preferably unsupported, meaning it comprises exclusively at least one precious metal compound.

[0018] In addition, the anode contains an electrically conductive platinum component. The electrically conductive platinum component is essentially unrestricted in form and composition. Two or more platinum components can also be used in combination. The platinum component serves to generate sufficiently high electrical conductivity in the anode, which contributes to the performance of the MEA. This is especially important because the proportion of OER in the anode is extremely low. Any quantity specifications relating to the platinum component mentioned below refer to the total quantity of all platinum components used in the anode when two or more platinum components are used.

[0019] The third essential component of the anode comprises a ceramic material. This ceramic material is essentially unrestricted in form and composition. It has been found that adding the ceramic material increases the anode layer thickness without compromising performance. In fact, the addition of the ceramic component does not increase the cell voltage during operation of the MEA according to the invention, thus maintaining particularly high catalytic activity. The ceramic material also offers significant advantages in terms of the long-term stability of the anode, and consequently, of the MEA and the resulting water electrolysis cell. This is because the anode layer thickness can be precisely controlled by adding the ceramic material. Since the proportion of OER in the anode is fixed, i.e., at a surface area of ​​0.10 to 0.28 mg / cm², this is particularly advantageous. 2Once the anode's electrical conductivity is specified and the platinum component is selected according to the required electrical conductivity, the layer thickness can be precisely controlled by adding a specific ceramic material. This ensures the anode is easy to handle and process, and exhibits good stability even under continuous operation. Naturally, two or more ceramic materials can be used in combination. Any quantities specified below regarding ceramic materials refer to the total quantity of all ceramic materials used in the anode when two or more are employed.

[0020] The fourth essential component of the anode comprises a proton-conducting polymer. This proton-conducting polymer simultaneously serves as a binder for both the anode components and the proton conductivity, resulting in improved performance of the MEA due to better proton transport.

[0021] According to the invention, the OER, the platinum component, and the ceramic material are present in one and the same layer, distributed within the proton-conducting polymer. Furthermore, for production and cost reasons, it is preferred if the anode consists of only one layer.

[0022] To further increase the performance of the MEA and thus improve its efficiency, the amount of precious metal-containing OER used in the anode can be further reduced. Preferably, the areal weight of the OER relative to the precious metal of the oxygen evolution catalyst is 0.15 mg / cm². 2 up to 0.25 mg / cm²2 .

[0023] Also for reasons of high efficiency and performance of the OER, the precious metal of the OER comprises iridium (Ir) and / or ruthenium (Ru). According to this embodiment, the basis weight of Ir and / or Ru is 0.10 mg / cm². 2 up to 0.28 mg / cm² 2 .

[0024] Due to its excellent stability and inertness to the reactions occurring in the anode, the ceramic material is preferably selected from TiO2, SnO2, fluoride-doped SnO2, ZrO2, SiO2, Nb2O5, Ta2O5, WO3, as well as alloys and mixtures thereof. The structure of the ceramic material is not further restricted. The ceramic material can be in a particulate, i.e., round, form, but can also exhibit branched or fibrous structures.

[0025] As already explained, the specific form of the platinum component used according to the invention is not limited. However, due to its very good electrical conductivity, the platinum component is preferably selected from platinum particles, platinum fibers, platinum nanotubes, and any mixtures thereof.

[0026] To improve the electrical conductivity within the anode, the material of the platinum component is advantageously selected from (metallic) platinum and alloys thereof. If platinum is used in the form of an alloy, the proportion of alloying elements in the platinum alloy is a maximum of 30 wt.% and, more preferably, a maximum of 20 wt.%, based on the platinum alloy, i.e., the total mass of the platinum alloy used in the anode.

[0027] For reasons of good processability and stability, the platinum component preferably has an aspect ratio of 1:1 to 10000:1. Due to the better dispersibility of the platinum component in the anode, the platinum component is spherical, thus having an aspect ratio of 1 and a diameter of 7 to 200 nm.

[0028] For high MEA performance, it is important that the anode has good electrical conductivity to ensure efficient electron conduction. For this purpose, a weight ratio of the platinum component to the oxygen evolution catalyst of 1:1.2 to 9:1 is advantageous. These amounts refer to the respective precious metal components for both the platinum and oxygen evolution catalysts.

[0029] To further enhance the performance of the MEA, a further advantageous development stipulates that the total volume fraction of the platinum component and the OER in the anode should be between 25 and 60% by volume. The volume of the anode is defined here as the volume of all inorganic solid components of the anode. Explicitly excluded are the volume of the pores and the volume of the ionomer, which is incorporated, in particular, into the free pore volume. Therefore, the porosity of the anode and the volume of the ionomer are factored out when determining its volume.

[0030] In light of the particularly high performance of the MEA with particularly good long-term stability, a volume fraction V corresponds to Ker the ceramic component to a total volume fraction V geSifest of the OER, the platinum component and the ceramic component preferably according to the following equation:

[0031] 12500 L 0ER 0.583 * cm 2 5000 * LOER 0.233 * cm2 1 - * -

[0032]

[0033] CM POER mg ' Loeb mg

[0034] In the equation, LQER is the areal weight of the OER in mg / cm², relative to the precious metal of the OER. 2 , p OE R is the density in mg / cm³ 3 of the OER and mp t / m O ER is a weight ratio of the platinum component to the OER.

[0035] To improve anode stability at very high MEA power levels, the volume fraction of the proton-conducting polymer, relative to the total anode volume, is preferably between 25 and 45% by volume. The total anode volume is defined here as the volume of all solid components of the anode; in other contexts, it refers to the volume of the inorganic solid components plus the volume of the proton-conducting polymer. The volume of the pores is explicitly excluded. Therefore, the porosity of the anode is factored out when determining its volume. If the volume fraction of the proton-conducting polymer is too high, the electrical transverse conductivity of the layer is impaired. If the volume fraction of the proton-conducting polymer is too low, the mechanical integrity, or in other words, the cohesion of the anode, is compromised.

[0036] For reasons of lightweight construction of the MEA while maintaining very good long-term stability, the layer thickness of the anode is preferably 2 to 5 pm.

[0037] Furthermore, a water electrolysis cell comprising the MEA according to the invention is also described according to the invention. Due to the use of the MEA according to the invention in the water electrolysis cell according to the invention, the latter is also characterized by very good performance combined with high long-term stability.

[0038] Examples relating to the present invention are described below to illustrate it. However, the invention is not limited to these examples.

[0039] Examples

[0040] Examples of ink production for anodes

[0041] Example 1

[0042] 1.63 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium), 1.67 g of a commercial platinum black catalyst (7 nm particle size, Platinum Black 32, Umicore, Germany), and 2.16 g of a commercial niobium oxide ceramic powder (ceramic grade, Taniobis GmbH, Germany) were mixed with 4.19 g of ionomer dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 3.2 g of water and 17.2 g of 1-propanol were added. The mixture was dispersed by a bead mill using spherical zirconia beads with a diameter of 1 mm for 60 min. The stirring disc had a diameter of 45 mm and a rotational speed of 2130 revolutions per minute was set. The quality of the dispersion was visually verified by checking for the absence of catalyst aggregates.The dispersion quality was further confirmed by good coating quality, i.e., no visible aggregates or streaks in the wet or dry film. Example 2.

[0043] The ink production was analogous to Example 1, except that a platinum black with a particle size of 11 nm (Platinum Black 25, Umicore, Germany) was used.

[0044] Example 3: The ink was produced analogously to Example 1, except that a platinum black with a particle size of 30 nm (Black Platinum Powder, Thermo Scientific Chemicals, Germany) was used.

[0045] Comparative example 1

[0046] 4.21 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium) were mixed with 4.93 g of ionomer dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 3.7 g of water and 17.2 g of 1-propanol were added. The ink preparation was carried out as in Example 1.

[0047] Comparative example 2

[0048] 2.9 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium) and 2.16 g of a commercial niobium oxide ceramic powder (Ceramic grade, Taniobis GmbH, Germany) were mixed with 5.63 g of ionomer dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 2.7 g of water and 16.9 g of 1-propanol were added. The ink preparation was carried out as in Example 1.

[0049] Comparative example 3

[0050] 1.35 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium) and 3.24 g of a commercial platinum black catalyst (7 nm particle size, Platinum Black 32, Umicore, Germany) were mixed with 3.49 g of ionomer dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 2.6 g of water and 14.5 g of 1-propanol were added. The ink preparation was carried out as in Example 1.

[0051] Comparative example 4

[0052] 1.35 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium) and 3.24 g of a commercial platinum black catalyst (30 nm, Black Platinum Powder, Thermo Scientific Chemicals, Germany) were mixed with 3.49 g of Ionomer Dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 14.5 g of tert-butanol and 0.2 g of 1-propanol were added. The ink preparation was carried out as in Example 1. Comparative Example 5

[0053] 1.08 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium), 1.14 g of a commercial silver nanoparticle powder (silver nanopowder, APS 20-40 nm, Thermo Scientific Chemicals, Germany), and 1.44 g of a commercial niobium oxide ceramic powder (ceramic grade, Taniobis GmbH, Germany) were mixed with 4.19 g of ionomer dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 2.6 g of water and 14.5 g of 1-propanol were added. The ink preparation was carried out as in Example 1.

[0054] Comparative example 6

[0055] 1.13 g of a commercial iridium-based catalyst (iridium(IV) oxide, Premion™; Thermo Scientific Chemicals, Germany, 85.4 wt% iridium), 0.74 g of a commercial platinum black catalyst (7 nm particle size, Platinum Black 32, Umicore, Germany), and 2.66 g of a commercial niobium oxide ceramic powder (Ceramic grade, Taniobis GmbH, Germany) were mixed with 3.49 g of ionomer dispersion Nation® D2020 (Chemours; USA) with an ionomer content of 21.3 wt%. Subsequently, 2.6 g of water and 14.5 g of 1-propanol were added. The ink preparation was carried out as in Example 1.

[0056] of anodes on a decal

[0057] Anode inks according to Examples 1-3 and Comparative Examples 1-6 were applied to a glass fiber reinforced PTFE substrate, in other words a decal, using a wire bar applicator. The wet film thickness was gradually adjusted by selecting a wire bar applicator with a suitable diameter to achieve an iridium metal loading (area weight of the OER relative to the precious metal) of 0.15 mg / cm². 2 To obtain the desired iridium metal content, the wet film thickness was varied between 10 pm and 100 pm by selecting spiral applicators with the appropriate wire diameters. After coating, the wet layers were dried in an oven at 110 °C for 5 minutes. The actual iridium metal loading was determined gravimetrically by measuring the exact decal weight before and after lamination of the catalyst-coated membrane (prepared as described below).

[0058]

[0059] Membranes

[0060] CCMs were manufactured using a Nation® N115 membrane (Chemours) in a press using a decal process. For this purpose, the membranes were positioned between anode and cathode decals (7.1 cm x 7.1 cm) and pressed at a temperature of 180 °C and a pressure of 1.5 MPa for 1 minute, so that the electrode layers were transferred from the decal substrate to the membranes.

[0061] The cathode was identical for all CCMs and consisted of a catalyst in which platinum was supported on carbon, and a Nation® ionomer binder. The catalyst-to-ionomer weight ratio in the cathode was 3:1, and the platinum loading was 0.3 mg / cm². 2 The cathode was also applied to glass fiber reinforced PTFE.

[0062] The anodes were varied and corresponded to the composition and loading of the previously mentioned examples and comparison examples.

[0063]

[0064] Layer thicknesses were determined using scanning electron microscopy on cross-sections of the finished CCMs.

[0065] Power / efficiency in the water electrolysis cell

[0066] The efficiency of the CCM was measured in a single cell with an active area of ​​25 cm². 2The cell consisted of platinum-plated titanium plates with a column bar flow field design on both the anode and cathode sides. The cathode-side flow field plate was additionally gold-plated. A 1 mm thick titanium sinter and carbon paper (Toray TGP-H-120) served as porous transport and gas diffusion layers on the anode and cathode sides, respectively. The cell was compressed to 155 bar and sealed with M8 screws. Twelve Belleville washers per screw ensured uniform pressure distribution within the cell. Deionized water with a conductivity of less than 1 pS / cm was circulated on the anode side. The cell was heated from room temperature to 60 °C within 20 minutes using heating pads applied to the end plates. Subsequently, the temperature was increased to 80 °C within another 20 minutes. Conditioning was achieved by ten cycles between 0 and 1 A / cm². 2with a holding time of 5 minutes for each step. To conclude the conditioning, the cell was held at 1 A / cm² for 10 minutes. 2 held.

[0067] Current-voltage characteristic curves (polarization curves) were recorded at 80 °C, 65 °C and 50 °C by increasing the current density from small to large values ​​(A / cm²). 2 ) with a holding time of 10 minutes each time. The steps were as follows:

[0068] 0.01 - 0.02 - 0.03 - 0.05 - 0.08 - 0.1 - 0.2 - 0.4 - 0.6 - 0.8 - 1.0 - 1.2 - 1.4 - 1.6 - 1.8 - 2.0 - 2.25 - 2.5 - 2.75 - 3.0 (each in A / cm²) 2 ).

[0069] Comparison of layer thicknesses and power / efficiency in water electrolysis cells - CCMs from examples and comparative examples

[0070] The table below provides an overview of the examples performed: lrO2 / Pt Ceramic lrO2 / Pt Ceramic Pt Layer thickness BeCell stress BeWt.% wt.%* wt.% vol.% vol.%* vol.% Morphology / pm rating*** at 3 A / cm 2 Evaluation*** Example 1 30 30 40 23 11 66 7 nm, sph.** 2.9 2.098 Example 2 30 30 40 23 11 66 11 nm, sph. 2.9 2.088 Example 3 30 30 40 23 11 66 30 nm, sph. 2.4 2.050 Comparison Example 1 100 0 0 100 0 0 / 0.7 2.078 Comparison Example 2 60 0 40 41 0 59 / 1 .1 2.200 Comparison Example 3 30 70 0 48 52 0 7 nm, sph. 1 .4 2.120 Comparison Example 4 30 70 0 48 52 0 30 nm, sph. 1.2 2.072 Comparison example 5 30 30 40 20 20 59 30 nm, sph. 2.4 2.226

[0071]

[0072] Comparison example 6 25 16 59 15 5 79 30 nm, sph. 3.3 >2.30

[0073] * In comparison example 5, this corresponds to the mass and volume fraction of silver.

[0074] s

[0075]

[0076] instead of platinum

[0077] ** sph. Stands for spherical

[0078] *** +: good, o: average, poor, very poor. The examples and comparative examples show that only with the anode composition according to the invention could a layer thickness in the advantageous range be achieved with regard to long-term stability, as well as good performance, in other words, a low cell voltage. A sufficiently high layer thickness is advantageous in light of reproducible manufacturability and a long anode lifespan. Further details, advantages, and features of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawing. Fig. 1 shows an MEA according to an advantageous further development and

[0079] Fig. 2 shows the anode from Fig. 1 in an enlarged sectional view.

[0080] The figures show only the essential aspects / components / elements of the present invention. All other aspects / components / elements have been omitted for clarity. Furthermore, identical reference numerals denote identical aspects / components / elements.

[0081] Figure 1 shows in detail an MEA 1 according to an advantageous embodiment. In this embodiment, a membrane 4 is surrounded on one side by a cathode 2 and on the opposite side by an anode 3. The membrane 4 is thus located between the cathode 2 and the anode 3. The anode 3 is a single layer. The MEA 1 can be used in particular in a water electrolysis cell and is therefore designed as a water electrolysis MEA.

[0082] Figure 2 shows an enlarged view of anode 3 from Fig. 1. It can be seen that anode 3 contains several components:

[0083] Reference numeral 5 denotes an oxygen catalyst (OER), which is a catalyst that produces oxygen from water. OER 5 contains precious metals and, due to its good catalytic performance, preferably comprises iridium and / or ruthenium. OER 5 is unsupported. The basis weight of the OER, based on the precious metal, is 0.10 mg / cm². 2 up to 0.28 mg / cm² 2 and is therefore very low, which, however, does not pose a disadvantage with regard to the performance of MEA 1. The reference area for calculating the areal weight of the OER is the area of ​​anode 3 in MEA 1.

[0084] Furthermore, the anode 3 comprises a platinum component 6. This component may also be a mixture of several platinum components. The platinum component 6 comprises platinum as the main element. However, it may also be a platinum alloy, with any alloying metals comprising a maximum of 20 wt.% based on the total mass of the platinum alloy. The specific shape of the platinum component 6 is not restricted. Preferably, shapes are selected from platinum particles, platinum fibers, platinum nanotubes, and any mixtures thereof, with an aspect ratio ranging from 1:1 to 10,000:1. If the platinum component 6 is spherical, it preferably has a diameter of 7 to 200 nm.

[0085] Furthermore, the anode 3 contains a ceramic material 7. This material can also consist of several ceramic materials differing in form and composition. The ceramic material 7 serves to adjust the layer thickness S of the anode 3 and is preferably selected from TiO2, SnO2, fluoride-doped SnO2, ZrO2, SiO2, Nb2O5, Ta2O5, WO3, as well as alloys and mixtures thereof. The layer thickness S of the anode 3 is particularly 2 to 5 pm, resulting in good stability and thus easy processing and consequently high long-term stability of the MEA 1.

[0086] The total volume fraction of the platinum component 6 and the OER 5 in the anode 3 is from 25 to 60 volume%, whereby the volume of the anode 3 is considered to be the volume of the inorganic solids that form the anode 3, i.e. the porosity and the volume of the ionomer are not included.

[0087] The solids of the anode 3 are distributed in a proton-conducting polymer 8, which provides good transport properties for protons.

[0088] To achieve a continuous electron transport path, and thus good layer conductivity, the particles of the oxygen catalyst and the platinum component 6 must be in direct contact with each other. The representation in Figure 2 is therefore to be understood as schematic and does not mean that particles of the OER 5 and the platinum component 6 are isolated from each other in the anode 3.

[0089] The specific design of anode 3 results in high performance for MEA 1, which manifests itself in a low cell voltage. Furthermore, the long-term stability of anode 3 is also improved by its specific design, resulting in a long service life for MEA 1 as well.

[0090] In addition to the foregoing written description of the invention, explicit reference is hereby made to the graphic representation of the invention in the figures for its supplementary disclosure. List of reference symbols

[0091] 1 MEA

[0092] 2 Cathode

[0093] 3 Anode

[0094] 4 proton-conducting membrane 5 OER

[0095] 6 Platinum component

[0096] 7 ceramic material

[0097] 8 proton-conducting polymer S layer thickness of the anode

Claims

Claims 1. Membrane electrode arrangement (1) comprising a cathode (2), an anode (3) and a proton-conducting membrane (4), wherein the proton-conducting membrane (4) is arranged between the cathode (2) and the anode (3), wherein the anode (3) comprises a noble metal-containing oxygen evolution catalyst (5), an electrically conductive platinum component (6), a ceramic material (7) and a proton-conducting polymer (8), where the areal weight of the oxygen evolution catalyst (5) is 0.10 mg / cm², based on the noble metal of the oxygen evolution catalyst (5). 2 up to 0.28 mg / cm² 2 amounts.

2. Membrane electrode arrangement (1) according to claim 1, wherein the areal weight of the oxygen evolution catalyst (5) based on the noble metal of the oxygen evolution catalyst (5) is 0.15 mg / cm². 2 up to 0.25 mg / cm² 2 amounts.

3. Membrane electrode arrangement (1) according to claim 1 or 2, wherein the noble metal of the oxygen evolution catalyst (5) comprises iridium and / or ruthenium.

4. Membrane electrode arrangement (1) according to one of the preceding claims, wherein the ceramic material (7) is selected from TiO2, SnO2, fluoride-doped SnO2, ZrO2, SiO2, Nb2O5, Ta2O5, WO3 and alloys and mixtures thereof.

5. Membrane electrode arrangement (1) according to one of the preceding claims, wherein the platinum component (6) is selected from platinum particles, platinum fibers, platinum nanotubes and any mixtures thereof.

6. Membrane electrode arrangement (1) according to one of the preceding claims, wherein the material of the platinum component (6) is selected from platinum and alloys thereof, wherein a proportion of alloying elements in the platinum alloy is a maximum of 30 wt.%, in particular a maximum of 20 wt.%, based on the platinum alloy.

7. Membrane electrode arrangement (1) according to any one of the preceding claims, wherein the platinum component (6) has an aspect ratio of 1:1 to 10000:

1.

8. Membrane electrode arrangement (1) according to any one of the preceding claims, wherein the platinum component (6) is spherical and has a diameter of 7 to 200 nm.

9. Membrane electrode arrangement (1) according to one of the preceding claims, wherein the weight ratio of the platinum component (6) to the oxygen evolution catalyst (5) is 1:1.2 to 9:

1.

10. Membrane electrode arrangement (1) according to one of the preceding claims, wherein the total volume fraction of the platinum component (6) and the oxygen evolution catalyst (5) in the anode (3) is 25 to 60 volume%, based on all inorganic components of the anode (3).

11. Membrane electrode arrangement (1) according to claim 10, wherein a volume fraction V Ker the ceramic component (7) to a total volume fraction V geSifestthe oxygen evolution catalyst (5), the platinum component (6) and the ceramic component (7) corresponds to the following equation: 12500 L 0ER 0.583 * cm 2 m pc V Ker 5000 L 0ER 0.233 * cm 2 in pt cm * POER m 9 * ° ER " m OER ~ V geSifest ~ cm * p 0ER mg * 0ER * m 0ER where LQER is the areal weight of the oxygen evolution catalyst (5) in mg / cm², based on the noble metal of the oxygen evolution catalyst (5). 2 , r OE R is the density in mg / cm³ 3 of the oxygen evolution catalyst (5) and mp t / m O ER is a weight ratio of the platinum component (6) to the oxygen evolution catalyst (5).

12. Membrane electrode arrangement (1) according to one of the preceding claims, wherein a volume fraction of the proton-conducting polymer (8) is 25 to 45 volume% based on the total volume of the anode (3).

13. Membrane electrode arrangement (1) according to one of the preceding claims, wherein the layer thickness (S) of the anode is 2 to 5 pm.

14. Water electrolysis cell comprising a membrane electrode arrangement (1) according to one of the preceding claims.

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