Assembly for fuel cell

Abstract

The invention relates to an assembly for a fuel cell or electrolytic cell having an acidic, alkaline, solid oxide or molten salt electrolyte, equipped with an anti-corrosion coating, and to such a fuel cell or electrolytic cell having an acidic electrolyte, said assembly comprising a non-conductive substrate (31), and an anti-corrosion coating (32) deposited on at least one surface of the substrate (31), the anti-corrosion coating (32) comprising at least one main layer based on tantalum nitride doped with one or more doping elements selected from the group of transition metals and / or lanthanide series elements.

Description

Technical Field

[0001] This disclosure relates to an assembly for a fuel cell or electrolyzer having an acidic electrolyte, an alkaline electrolyte, a solid oxide electrolyte, or a molten salt, and to such a fuel cell or electrolyzer having an acidic electrolyte, an alkaline electrolyte, a solid oxide electrolyte, or a molten salt.

[0002] - Such components with conductive properties are particularly suitable for equipping: - Proton exchange membrane fuel cell (PEMFC). - Phosphoric acid fuel cell (PAFC). - Direct methanol fuel cell (DMFC) - Direct ethanol fuel cells (DEFC), or - Direct glycol fuel cell (DEGFC). Background Technology

[0003] Conductive components used in fuel cells, such as end plates, bipolar plates, and interconnects, are exposed to extremely harsh oxidizing conditions (particularly due to the presence of oxygen and / or water) and corrosive conditions (particularly due to acidic effluents from the electrolyte). Without adequate protection, these components can deteriorate rapidly, resulting in loss of conductivity and contamination of the fuel cell environment (particularly its electrolyte and / or its catalyst) by corrosion products.

[0004] In particular, alkaline electrolyte fuel cells are exposed to challenging alkaline corrosive conditions, which is especially due to alkaline effluents from the electrolyte.

[0005] This is even more serious for solid oxide electrolyte fuel cells, as these cells operate at temperatures between 500°C and 1000°C, which significantly promotes the corrosion process.

[0006] These corrosive conditions are particularly severe in molten salt electrolyte fuel cells or electrolyzers, partly due to the high operating temperature (typically around 650°C) and partly due to the presence of molten salt in the electrolyte.

[0007] To limit this corrosion, the first option is to use very special alloys that are inherently highly corrosion-resistant. This includes, in particular, Inconel 625. However, these special alloys are expensive. Furthermore, their natural corrosion resistance may prove insufficient in some applications.

[0008] The second option is to use more conventional materials for these conductive components, but protect them with an anti-corrosion coating. Many materials, particularly graphite or conductive metal oxide coatings, have been tested in the scientific literature.

[0009] However, in addition to excellent corrosion protection, this anti-corrosion coating must also possess good stability and sufficient conductivity to avoid hindering the electrical operation of the fuel cell. Specifically, the coating's conductivity must remain greater than 100 S / cm. Furthermore, the coating must be thin enough, for example, less than 5 µm, to avoid altering the geometry of the assembly, especially when the assembly contains channels.

[0010] However, to date, the only known solution in the fields of proton exchange membrane fuel cells (PEMFC), phosphoric acid fuel cells (PAFC), alkaline fuel cells (AFC), direct urea fuel cells (DUFC), solid oxide fuel cells (SOFC), proton ceramic fuel cells (PCFC), or direct carbon fuel cells (DCFC) that can achieve a lifespan of more than 5,000 hours and an acceptable degradation rate (i.e., less than 40 µV / h) is a pure gold coating with a thickness of 200 to 500 nm.

[0011] The same applies to direct methanol fuel cells (DMFC), direct ethanol fuel cells (DEFC), or direct ethylene glycol fuel cells (DEGFC), or to molten salt electrolyte fuel cells.

[0012] However, this pure gold coating significantly increases the cost of fuel cells. Therefore, when all conductive components of a fuel cell are equipped with this coating, the cost of the coating alone can be as high as half the total cost of the fuel cell.

[0013] Furthermore, even pure gold coatings will eventually wear down, contaminating the fuel cell environment. In particular, gold particles may deposit on certain components of the fuel cell and form electrical connections in unwanted locations, thereby reducing the efficiency of the fuel cell.

[0014] Therefore, there is indeed a need for an assembly for a fuel cell or electrolyzer having an acidic electrolyte, an alkaline electrolyte, a solid oxide electrolyte, or a molten salt electrolyte, and a fuel cell or electrolyzer having an acidic electrolyte, an alkaline electrolyte, a solid oxide electrolyte, or a molten salt electrolyte comprising such an assembly, which at least partially eliminates the disadvantages inherent in the aforementioned known configurations.

[0015] Invention disclosure

[0016] This disclosure relates to an assembly for a fuel cell or electrolyzer having an acidic electrolyte, an alkaline electrolyte, a solid oxide electrolyte, or a molten salt electrolyte, comprising: - Non-conductive substrate and - An anti-corrosion coating deposited on at least one surface of the substrate. The corrosion-resistant coating comprises at least one main layer, which is based on tantalum nitride doped with one or more doping elements selected from transition metals and / or lanthanides.

[0017] As will be explained in detail below, such doped tantalum nitride layers provide excellent corrosion protection while also exhibiting good electrical conductivity. In particular, the inclusion of one or more doping elements enhances the chemical stability of tantalum nitride, which is normally in a metastable state, by forming a solid solution.

[0018] Therefore, it exhibits excellent acid corrosion resistance in both oxidizing and reducing environments within a temperature range of 0°C to 300°C.

[0019] In particular, it exhibits excellent resistance to oxidation caused by oxidants (O2 or air), as well as corrosion caused by alkaline effluents generated by the membrane and the presence of liquid water generated by the battery.

[0020] Similarly, it also exhibits excellent resistance to high-temperature corrosion (especially caused by molten salt in molten salt fuel cells) and carbonization.

[0021] Therefore, the obtained components can perform their current conduction function efficiently and persistently under highly oxidized conditions in fuel cells or electrolyzers.

[0022] In particular, due to the high stability of doped tantalum nitride, the coating degrades very little over time: this reduces the risk of decreased component conductivity over time, and also reduces the risk of contamination of the fuel cell or electrolyzer environment (especially its electrolyte or catalyst), thereby reducing its efficiency. Therefore, such a coating enables the component to achieve an extremely long service life, approximately between 20,000 and 30,000 hours.

[0023] Furthermore, the cost of obtaining a doped tantalum nitride coating is significantly lower than that of a pure gold coating, which enables a significant reduction in the total cost of fuel cells or electrolyzers.

[0024] Tantalum nitride also has the advantage of remaining stable up to about 3000°C, which makes it suitable for use in a very wide range of applications, including extremely high temperatures.

[0025] Furthermore, due to the high conductivity of this anti-corrosion coating, a non-conductive substrate can be used to replace the usual conductive substrate while maintaining the conductivity of the component, since the conductivity is provided by the anti-corrosion coating itself, rather than by the substrate.

[0026] This opens up a wider range of possible materials, allowing for the selection of cheaper and / or lower-density, and therefore lighter, materials without the need for conductive fillers. Materials that are easy to mold can also be chosen.

[0027] In some embodiments, the component is a component for a fuel cell or electrolyzer having an acidic electrolyte and a gaseous fuel.

[0028] In other embodiments, the component is a component for a fuel cell or electrolyzer having an acidic electrolyte and liquid fuel.

[0029] In some embodiments, the substrate is made of polymeric materials, particularly thermoplastics and / or elastomers.

[0030] Compared to traditional metal substrates, this allows for a reduction in component cost and weight.

[0031] In some embodiments, the substrate is made of an organic matrix composite material. Such materials are lightweight while providing good mechanical strength.

[0032] In some embodiments, the main layer is substantially made of tantalum nitride doped with one or more doping elements selected from transition metals and / or lanthanides. Therefore, the main layer is substantially homogeneous.

[0033] In some embodiments, the master layer is biphase or multiphase. In particular, the master layer may have a compositional gradient, for example, in a direction perpendicular to the substrate.

[0034] In some embodiments, the main layer is made primarily of tantalum nitride.

[0035] Accordingly, the main layer can have compositional variations that affect the tantalum nitride crystal structure and / or doping state. In particular, a crystal structure gradient is beneficial for improving stress adaptation between the coating and its substrate, which improves the mechanical properties of the entire system and limits cracking and / or delamination of the coating.

[0036] In some embodiments, the electrolyte in a fuel cell or electrolyzer is a proton exchange membrane.

[0037] In some embodiments, the electrolyte in the fuel cell or electrolyzer is phosphoric acid.

[0038] In some embodiments, the component has a conductive function within the fuel cell or electrolyzer.

[0039] In particular, the component can be an end plate, bipolar plate, or interconnect of a fuel cell or electrolyzer.

[0040] In some embodiments, the tantalum nitride in the main layer has a hexagonal crystal system. In fact, in addition to its excellent corrosion resistance, hexagonal tantalum nitride has electrical conductivity almost as good as gold.

[0041] In some embodiments, the tantalum nitride in the main layer is cubic. In fact, although cubic tantalum nitride has a slightly lower conductivity than hexagonal tantalum nitride, it also has excellent corrosion resistance, especially in the case of doping as shown here.

[0042] In some embodiments, the total dopant content in the main layer is between 1 ppm and 10 at%, particularly between 10 ppm and 1 at%, and even more particularly between 0.2 and 0.5 at%.

[0043] In some embodiments, the primary doping element is selected from zirconium, hafnium, nickel, vanadium, titanium, niobium, chromium and / or molybdenum.

[0044] In some embodiments, the dopant element used (preferably the only dopant element) is vanadium (V).

[0045] In fact, vanadium readily forms solid solutions with tantalum nitride, thereby increasing its stability. Furthermore, vanadium is difficult to oxidize: therefore, even if small amounts of vanadium are released into the environment of a fuel cell or electrolyzer, their impact on the electrolyte or catalyst will be very small.

[0046] In some embodiments, the doping element used (preferably the only doping element) is nickel (Ni). This dopant is particularly preferred for fuel cells having an acidic electrolyte and a liquid fuel.

[0047] In fact, nickel is already present in at least one catalyst in most acidic electrolyte and liquid fuel cells. Therefore, even if a small amount of nickel from the coating is released into the fuel cell environment, its impact is reduced because it will not affect the catalyst that already contains nickel.

[0048] In some embodiments, the content of the major dopant in the main layer is between 1 ppm and 10 at%, particularly between 10 ppm and 1 at%, and even more particularly between 0.2 and 0.5 at%.

[0049] In some embodiments, the thickness of the anti-corrosion coating is between 5 nm and 5 µm, particularly between 10 nm and 1 µm, and especially between 100 nm and 300 nm.

[0050] In some embodiments, the anti-corrosion coating comprises multiple stacked layers, particularly 2 to 10 layers.

[0051] The material of the main layer constitutes the main material, and the anti-corrosion coating includes at least one sub-layer based on a sub-material that is different from the main material.

[0052] This multi-layered structure enhances the mechanical strength of the coating, and each interface between the two different layers helps deflect any cracks that appear in the material. Therefore, the risk of cracks propagating to the substrate is reduced, thus keeping the substrate protected from corrosion.

[0053] In some embodiments, the anti-corrosion coating comprises at least three layers, each containing a different material.

[0054] In some embodiments, the thickness of each layer of the coating is between 1 and 500 nm, particularly between 10 and 100 nm.

[0055] In some embodiments, the top layer of the anti-corrosion coating is a primary layer made of a host material. Therefore, the first line of protection is ensured by the host material, which typically has the best anti-corrosion properties. However, in other embodiments, the top layer of the anti-corrosion coating may be a secondary layer.

[0056] In some embodiments, the main material occupies at least 30% of the volume of the anti-corrosion coating, particularly at least 50%. Overall, this provides exceptionally high levels of corrosion protection.

[0057] In some embodiments, the anti-corrosion coating comprises alternating layers of primary and secondary materials. This alternation is particularly effective in preventing cracks from reaching the substrate.

[0058] In some embodiments, the secondary material is crystalline tantalum nitride having a different crystal system and / or doping state than the primary material.

[0059] In particular, the secondary material can contain one or more different doped elements, or it can be undoped. In this way, the secondary material still maintains very high corrosion resistance, ensuring satisfactory corrosion protection even if the main layer cracks.

[0060] In some embodiments, the sublayer consists essentially of sub-materials.

[0061] In some embodiments, the sublayer is biphase or multiphase.

[0062] In particular, the sublayer can have a compositional gradient, for example, in a direction perpendicular to the substrate.

[0063] In some embodiments, the sublayer is made primarily of tantalum nitride.

[0064] Accordingly, the sublayer can have compositional variations that affect the tantalum nitride crystal structure and / or doping state.

[0065] In particular, gradient layers in the crystal structure are beneficial for improving stress adaptation between a given layer and the layer below it, which improves the mechanical properties of the entire system and limits cracking and / or delamination of the coating at the interface. Doping gradients can also allow for better adaptation between two consecutive layers, avoiding abrupt changes in composition (which could result in mechanically weaker interfaces).

[0066] In some embodiments, the main layer is deposited using a co-sputtering process. The co-sputtering process can in particular combine high-power pulsed magnetron sputtering (HiPIMS) using a tantalum target and magnetron sputtering using a target containing doped elements.

[0067] Examples of high-power pulsed magnetron sputtering processes are specifically described in document FR3097237.

[0068] This disclosure also relates to a fuel cell or electrolyzer having an acidic electrolyte, including at least one component according to any of the foregoing embodiments.

[0069] In some embodiments, the fuel cell is of the electrolyte and gaseous fuel type.

[0070] In some embodiments, the fuel cell is a proton exchange membrane fuel cell (PEMFC) type.

[0071] In some embodiments, the fuel cell is a phosphoric acid fuel cell (PAFC) type.

[0072] In some embodiments, the fuel cell is configured to be supplied with hydrogen (H2).

[0073] In some embodiments, the fuel cell is of the electrolyte and liquid fuel type.

[0074] In some embodiments, the fuel cell is a direct methanol fuel cell (DMFC) type.

[0075] In some embodiments, the fuel cell is a direct ethanol fuel cell (DEFC) type.

[0076] In some embodiments, the fuel cell is a direct glycol fuel cell (DEGFC) type.

[0077] In some embodiments, the fuel cell is configured to be supplied with methanol (CH3OH), ethanol (C2H5OH), or ethylene glycol (HOC2H4OH).

[0078] In some embodiments, the electrolyte of the fuel cell or electrolyzer is a solution of potassium hydroxide (KOH) and / or sodium hydroxide (NaOH).

[0079] In some embodiments, the fuel cell is an alkaline fuel cell (AFC) type.

[0080] In some embodiments, the fuel cell is a metal / air fuel cell type. This can be, in particular, a zinc / air cell, an aluminum / air cell, a magnesium / air cell, or a lithium / air cell.

[0081] In some embodiments, the fuel cell is a direct urea fuel cell (DUFC) type.

[0082] In some embodiments, the fuel cell is of the type supplied with gaseous fuel (preferably hydrogen H2).

[0083] In some embodiments, the fuel cell is configured to be supplied with urea CO(NH2)2.

[0084] In some embodiments, the electrolyte of the fuel cell or electrolyzer is ceramic, preferably yttrium-stabilized zirconium oxide (YSZ).

[0085] In some embodiments, the electrolyte of the fuel cell or electrolyzer comprises one or more molten salts, preferably sodium carbonate (NaCO3), potassium carbonate (K2CO3), and / or lithium carbonate (Li2CO3).

[0086] In some embodiments, the electrolyte of the fuel cell or electrolyzer comprises a porous oxide matrix, preferably lithium aluminum oxide.

[0087] In some embodiments, the dopant element used (preferably the only dopant element) is yttrium (Y). This dopant is particularly preferred for fuel cells having a solid oxide electrolyte.

[0088] In fact, in most solid oxide fuel cells, the electrolyte already contains yttrium. Therefore, even if a small amount of yttrium from the coating is released into the fuel cell environment, its impact is reduced because it does not affect the electrolyte.

[0089] In some embodiments, the dopant element used (preferably the only dopant element) is chromium (Cr). This dopant is particularly preferred for fuel cells with molten salt electrolytes.

[0090] In reality, given the dominant critical oxidation conditions in fuel cells or electrolyzers with molten salt electrolytes, minimal oxidation of the coating is almost inevitable, regardless of its tolerance. Therefore, selecting elements with good electrical conductivity, such as chromium, ensures that good conductivity levels are maintained within the fuel cell or electrolyzer even under contamination by such dopant elements.

[0091] This disclosure also relates to a solid oxide electrolyte or molten salt fuel cell or electrolyzer, including at least one component according to any of the foregoing embodiments.

[0092] In some embodiments, the fuel cell is a solid oxide fuel cell (SOFC) type.

[0093] In some embodiments, the fuel cell is a proton ceramic fuel cell (PCFC) type.

[0094] In some embodiments, the fuel cell is a direct carbon fuel cell (DCFC) type.

[0095] In some embodiments, the fuel cell is of the molten carbonate fuel cell (MCFC) type.

[0096] In some embodiments, the electrolyzer is a molten carbonate electrolyzer (MCEC) type.

[0097] In some embodiments, the fuel cell is a direct urea fuel cell (DUFC) type.

[0098] In some embodiments, the fuel cell is configured to be supplied with gaseous fuel.

[0099] In some embodiments, the fuel cell is configured to be supplied with hydrogen (H2), ammonia (NH3), or methane (CH4).

[0100] In some embodiments, the fuel cell is configured to be powered by carbon-rich fuel (preferably coal or biomass).

[0101] In some embodiments, the fuel cell is configured to be supplied with urea CO(NH2)2.

[0102] In this disclosure, when a given material constitutes a component or part of a component and is qualitatively representative of the main material, the component or part of the component is considered to be based on the given material.

[0103] In this disclosure, a component or a portion thereof is considered to be substantially made of a given material when at least 80% (preferably 90%, more preferably 99%) of the component or a part thereof is composed of the given material.

[0104] The above-described features and advantages, as well as other features and advantages, will become apparent upon reading the following detailed description of exemplary embodiments of the proposed components and fuel cells. This detailed description refers to the accompanying drawings.

[0105] Brief description of the attached figures

[0106] The accompanying schematic diagrams are primarily intended to illustrate the principles of this disclosure. In the figures, identical elements or portions of elements are identified by the same reference numerals. Furthermore, elements or portions of elements belonging to different embodiments but having similar functions are identified in the figures by reference numerals increasing in increments such as 100, 200, etc.

[0107] This disclosure will be better understood by reading the following detailed description and in conjunction with the embodiments given by way of non-limiting example with reference to the accompanying drawings, and other features and advantages will become apparent. These embodiments may supplement the understanding of this disclosure and, where appropriate, contribute to its definition, wherein: [ Figure 1 ] Figure 1 This is a schematic diagram of a fuel cell based on this disclosure; [ Figure 2 ] Figure 2 yes Figure 1 A schematic diagram of a fuel cell cell; [ Figure 3 ] Figure 3 This is a schematic diagram of a first example of a component according to this disclosure; [ Figure 4 ] Figure 4 The apparatus is illustrated schematically, allowing the production of coatings according to this disclosure; [ Figure 5 ] Figure 5 It is a graph illustrating the corrosion test results of a first example of a component according to this disclosure; [ Figure 6 ] Figure 6 The microstructure of the cubic TaN coating deposited by high-power pulsed magnetron sputtering is shown in cross-sectional and front views. [ Figure 7 ] Figure 7 This is a graph illustrating the corrosion test results of a second example of a component according to this disclosure; [ Figure 8 ] Figure 8 This is a schematic diagram of the third example of the component; [ Figure 9 ] Figure 9 It is a graph illustrating the corrosion test results according to the third example of this disclosure; [ Figure 10 ] Figure 10 The microstructure of the hexagonal TaN coating deposited by high-power pulsed magnetron sputtering is shown in cross-sectional and front views. [ Figure 11 ] Figure 11 The microstructure of a hexagonal TaN coating deposited by conventional magnetron sputtering is shown in cross-sectional and front views; and [ Figure 12 ] Figure 12 This is a schematic diagram of a battery cell, another example of a fuel cell; [ Figure 13 ] Figure 13 This is a schematic diagram of yet another example of a fuel cell; [ Figure 14 ] Figure 14 This is a schematic diagram of yet another example of a fuel cell; [ Figure 15 ] Figure 15 This is a schematic diagram of a battery cell, another example of a fuel cell. Detailed Implementation

[0108] To make this disclosure more specific, examples of components and fuel cells are described in detail below with reference to the accompanying drawings. Note that the invention is not limited to these examples.

[0109] Figure 1 A fuel cell 1 according to the present invention is schematically shown. This fuel cell 1 includes two end plates 11, 12, and battery cells 20 are stacked between them along the stacking direction X.

[0110] Each battery cell 20 includes, according to Figure 1 The order defined from left to right is: first bipolar plate 21, first diffusion layer 22, first electrode 23, electrolyte 24, second electrode 25, second diffusion layer 26, and second bipolar plate 27.

[0111] The bipolar plates 21 and 27 function to deliver reactants and, as needed, to deliver heat transfer fluids that cool the battery cell when it reaches its nominal operating mode. Therefore, each surface of the bipolar plates 21 and 27 is provided with a network of channels 21a and 27a. The bipolar plates 21 and 27 also function to conduct current between successive battery cells 20. Thus, each bipolar plate 21 and 27 is located at the interface between two consecutive battery cells 20, and the second bipolar plate 27 of the Nth battery cell 20 constitutes the first bipolar plate 21 of the (N+1)th battery cell 20, thereby connecting the Nth and (N+1)th battery cells 20 in series.

[0112] End plates 11 and 12 serve the same function as bipolar plates 21 and 27, except that they are positioned at both ends of the stack, thereby closing the left side of the first battery cell 20 and the right side of the last battery cell 20, respectively. Therefore, end plates 11 and 12 have a network of channels 11a and 12a on only one side. They are also conductive, forming the terminals of the entire fuel cell. Thus, the terminals of the load 2 to be powered (e.g., a motor) can be connected to each end plate 11 and 12.

[0113] The function of diffusion layers 22 and 26 is to allow reactants to diffuse from bipolar plates 21 and 27 to the associated electrodes 23 and 25, and for reaction products to diffuse from the same electrodes 23 and 25 to bipolar plates 21 and 27. This diffusion can be achieved, in particular, through a network of grooves or holes.

[0114] Electrodes 23 and 25 are the sites of the electrochemical half-reactions that ensure the operation of fuel cell 1: therefore, the first electrode 23 constitutes the anode, and the second electrode 25 constitutes the cathode. Electrodes 23 and 25 are porous, preferably microporous, to allow reactants to enter and reaction products to exit. The first electrode 23 and / or the second electrode 25 are provided with a catalyst for catalyzing the electrochemical half-reaction.

[0115] The function of electrolyte 24 is to allow certain ions to migrate between anode 23 and cathode 25, while preventing electrons from the oxidation half-reaction at anode 23 from passing through. The electrons thus formed... - The electrons are then conducted to the cathode 25 of the adjacent preceding cell 20, where they are consumed in a reduction half-reaction. The electrons generated by the first cell 20 are collected by the first end plate 11 to power the load 2, and then pass through the second end plate 12 to the cathode 25 of the last cell 20.

[0116] Figure 2 The operation of the battery cell 20 in the context of the first exemplary embodiment is explained in more detail. In the first example, the fuel cell 1 is a proton exchange membrane (PEMFC) type fuel cell.

[0117] In this fuel cell 1, the fuel supplied to the anode 23 is hydrogen (H2), while the fuel supplied to the cathode 25 is air.

[0118] Electrolyte 24 consists of a proton exchange membrane, which allows protons (H+) to pass through. + Through, while preventing electron e - The proton exchange membrane also prevents the passage of any gas. Platinum is used as a catalyst in both anode 23 and cathode 25.

[0119] Therefore, anode 23 is the site of the following oxidation half-reaction: H2 → 2H + + 2e - Then, cathode 25 is the site of the following reduction half-reaction: 4H + + 4e - + O2 → 2H2O Therefore, the overall operating equations for fuel cell 1 are as follows: 2H₂ + O₂ → 2H₂O In this proton exchange membrane battery, membrane 24 acts as an acidic electrolyte. It can be a Nafion (registered trademark) based membrane, i.e., a fluoropolymer copolymer based on sulfonated tetrafluoroethylene, or a polybenzimidazole membrane doped with phosphoric acid.

[0120] Due to this highly corrosive environment, end plates 11 and 12 and bipolar plates 21 and 27 must be able to resist corrosion while continuing to perform their electrical conductivity function.

[0121] Figure 3 Such a component according to a first exemplary embodiment is schematically shown and is indicated by general reference numeral 30.

[0122] Therefore, component 30 includes a non-conductive substrate 31 (e.g., made of an organic matrix composite material) and an anti-corrosion coating 32 deposited on the substrate 31, the anti-corrosion coating 32 having a thickness e1 of 380 nm.

[0123] In the first example, the anti-corrosion coating 32 comprises a monolayer of tantalum nitride (TaN) doped with zirconium (Zr). This compound has the molecular formula Ta. 1-x Zr x N (where 0 < X ​​< 1) has a stable crystal structure in which zirconium atoms replace tantalum atoms Ta, thus forming a solid solution.

[0124] In this example, the compound has a cubic crystal system, more precisely, a face-centered cubic lattice. However, the compound can also crystallize in a hexagonal crystal system, which is also quite suitable.

[0125] In this example, the zirconium content in the compound is 5.8 + / - 0.6 at%.

[0126] Such an anti-corrosion coating 32 can be used Figure 4 The schematically shown device 50 is deposited on the substrate 31. The device 50 is capable of high-power pulsed magnetron sputtering co-sputtering.

[0127] The apparatus 50 includes a chamber 51 for containing a plasma-generating gas, such as a mixture of argon and nitrogen. The apparatus also includes a source (not shown) of the plasma-generating gas in communication with the chamber 51. The pressure in the chamber 51 is fixed between 0.1 and 20 Pa. The gas mixture contains 5 to 90 at% nitrogen. In this example, the pressure is fixed at 0.15 Pa, and the argon and nitrogen gas mixture contains 10% nitrogen.

[0128] The chamber 51 contains a tantalum target 52 constituting a first cathode and a zirconium target 53 constituting a second cathode. The two targets 52 and 53 are arranged on the same side of the chamber 51, forming a 90° angle with each other.

[0129] The substrate 31 to be coated forms the anode, which is arranged in the chamber 51, facing the targets 52 and 53, and is perpendicular to and centered on the angle bisector of the two targets 52 and 53.

[0130] In this example, the first target 52 contains more than 99 at% tantalum, preferably more than 99.9 at%. The second target 53 contains more than 99 at% zirconium, preferably more than 99.9 at%.

[0131] During the deposition of coating 32, the tantalum target 52 is polarized using pulsed polarization, optionally superimposed with continuous polarization. The polarization of the first target 52 is applied by a first power supply device 54, which includes a voltage pulse generator electrically connected to the tantalum target 52.

[0132] A voltage pulse generator is capable of applying pulsed polarization to the tantalum target 52. This configuration is specifically described in document FR3097237.

[0133] The pulse width can range from 1 µs to 900 µs. The pulse frequency can range from 50 Hz to 5000 Hz. The pulse voltage can range from -100 V to -1500 V.

[0134] In this example, the pulse width is 30 µs, the pulse frequency is 1000 Hz, and the voltage is -1000 V.

[0135] Similarly, the zirconium target 53 is polarized by a second power supply device 55, which is configured to ensure radio frequency polarization at a frequency of approximately 13.6 MHz and a power between 10 W and 1000 W.

[0136] However, in other examples, the second power supply device 55 may be configured to provide continuous polarization with a voltage between -100 V and -1500 V, and / or pulsed polarization with a pulse width between 1 µs and 900 µs, a pulse frequency between 50 Hz and 5000 Hz, and a pulse voltage between -100 V and -1500 V.

[0137] In chamber 51, in a nitrogen-containing atmosphere, a voltage is applied between target 52 and substrate 31 to generate plasma. Electrons are generated by target 52 and ionize the constituent atoms of the plasma through collisions. One or more permanent magnets (not shown) can be introduced into chamber 51 near target 52, whose magnetic fields confine the generated electrons near target 51, increasing the probability of collisions between electrons and plasma atoms there. When such collisions occur, high-energy particles are generated, which can bombard target 52 and tear particles from target 52 through elastic impact. The particles thus torn from target 52 can then be deposited on substrate 31 to form coating 32.

[0138] Similarly and simultaneously, particles from target 53 are also sputtered from target 53 onto substrate 31. The amount of doped particles (here, zirconium) in coating 32 can be adjusted by changing the electrical power applied to the second target 53. For example, in this example, a power of 5 W is applied to zirconium target 53.

[0139] Specifically, in this process, the substrate 31 is not heated during the deposition of the coating 32.

[0140] Accordingly, the pulse voltage, pulse width, and pulse frequency of the tantalum target 52 polarization are adjusted so that the energy difference between the incident electrons (approximately a few eV, where 1 eV = 11,600 K) and the substrate 31 enables ultrafast quenching conditions, i.e., a cooling rate of approximately 106 K / s to 108 K / s, when particles in the plasma reach the substrate 31.

[0141] By adjusting the pulse parameters in this way, the energy distribution of the discharged electrons can be obtained, thereby obtaining a cooling rate suitable for the incident particles to contact the substrate 31.

[0142] This allows for the fixation of the metastable configuration of the deposited coating 32, thereby fixing the target crystallinity without heating the substrate 31.

[0143] Furthermore, the substrate 31 can be polarized during the deposition process. For this purpose, the substrate 31 can be polarized using continuous polarization (voltage between 1 V and 1500 V) and / or pulsed polarization (pulse width between 1 µs and 900 µs, pulse frequency between 10 Hz and 5000 Hz, and pulse voltage between 1 V and 1500 V). In particular, pulsed polarization is advantageous for removing partial charges from the non-conductive substrate by recombination with plasma. This effect diminishes as the coating is deposited because the coating is conductive.

[0144] Figure 5 The corrosion test results related to the coating 32 used in the first exemplary embodiment are now described. This cyclic voltammetry test was performed in the laboratory at room temperature by immersing the working electrode (made of the material under test) and the platinum counter electrode in a 0.5 mol / L phosphoric acid bath, changing the potential applied to the working electrode relative to the counter electrode and recording its current response.

[0145] Curve 61 corresponds to the working electrode made of 316L stainless steel, which constitutes the reference material.

[0146] Curve 62 corresponds to the working electrode made of 316L stainless steel and completely covered with a cubic tantalum nitride coating doped with 5.8 + / - 0.6 at% zirconium Zr, i.e., coating 32 according to the first exemplary embodiment.

[0147] Curve 63 corresponds to the working electrode made of 316L stainless steel and completely covered with a cubic tantalum nitride coating doped with 6.0 + / - 0.4 at% zirconium Zr, i.e., coating 32 according to a variant embodiment.

[0148] like Figure 5 As shown, curves 62 and 63 (corresponding to the anti-corrosion coating 32 according to the first exemplary embodiment and its variants) have a significantly wider stability plateau than curve 61 corresponding to the uncoated reference material 31, thus confirming that the uncoated reference material 31 is protected by the anti-corrosion coating 32.

[0149] The test also measured the corrosion potential and current of these different samples: [Table 1]

[0150] Therefore, the corrosion current I of the anti-corrosion coating 32 according to this exemplary embodiment and its variations corr The corrosion resistance of these coatings is more than 30% lower than that of the uncoated reference material 31, thus confirming their excellent corrosion resistance.

[0151] also, Figure 6 The microstructure (cross-sectional and front view) of a cubic tantalum nitride coating deposited using a high-power pulsed magnetron sputtering process according to this example is illustrated. The scale shown at the bottom of each view corresponds to 1 µm.

[0152] These two views show that the coating has a fine and uniform microstructure, which means good mechanical strength, especially good resistance to the propagation of cracks within the coating.

[0153] In contrast, this coating deposited by conventional magnetron sputtering processes results in a columnar microstructure that is prone to fracture.

[0154] It is equally important to note that the anti-corrosion coating 32 according to the first exemplary embodiment and its variations has a conductivity well above 100 S / cm; this ensures that it has sufficient conductivity to satisfactorily conduct electrons within a fuel cell or electrolyzer, even if the substrate itself is not conductive. In fact, cubic tantalum nitride deposited by high-power pulsed magnetron sputtering at 160°C has a conductivity of 538 S / cm.

[0155] In the first example, the tantalum nitride (TaN) forming the anti-corrosion coating 32 is doped with zirconium.

[0156] However, in other examples, other doping elements from transition metals or lanthanides can be used as replacements or supplements for zirconium.

[0157] In a particularly exemplary embodiment, the anti-corrosion coating comprises a monolayer of tantalum nitride (TaN) doped with hafnium (Hf). This molecular formula is Ta 1-x HF x The N compound has a stable crystal structure in which zirconium atoms are replaced by hafnium atoms, thus forming a solid solution.

[0158] In the second example, the compound also has a cubic crystal system, more precisely, a face-centered cubic lattice. However, the compound can also crystallize in a hexagonal crystal system, which is also quite suitable.

[0159] In the second example, the hafnium content in the compound was 5.7 + / - 0.5 at%.

[0160] The anti-corrosion coating can be deposited on the substrate using a method very similar to the first example, simply by replacing the zirconium target 53 with a hafnium target.

[0161] With similar Figure 5 In this way, Figure 7 The corrosion test results related to the second exemplary embodiment are described. This cyclic voltammetry test was performed under the same conditions as the test performed for the first exemplary embodiment.

[0162] Curve 161 corresponds to the working electrode made of 316L stainless steel, which constitutes the reference material.

[0163] Curve 162 corresponds to the working electrode made of 316L stainless steel and completely covered with a cubic tantalum nitride coating doped with 5.7 + / - 0.7 at% hafnium Hf, i.e., the coating according to the second exemplary embodiment.

[0164] Curve 163 corresponds to the working electrode made of 316L stainless steel and completely covered with a cubic tantalum nitride coating doped with 5.3 + / - 0.5 at% hafnium Hf, i.e., the coating according to a variant embodiment of the second example.

[0165] like Figure 7 As shown, curves 162 and 163 (corresponding to the anti-corrosion coating according to the second exemplary embodiment and its variations) have a significantly wider stability plateau than curve 161 corresponding to the uncoated reference material, thus confirming that the reference material is protected by the anti-corrosion coating.

[0166] The test also measured the corrosion potential and current of these different samples: [Table 2]

[0167] Therefore, the corrosion current I of the anti-corrosion coating according to the second exemplary embodiment and its variations corrThe corrosion resistance of these coatings is more than 10% lower than that of the uncoated reference material, thus confirming their excellent corrosion resistance.

[0168] Figure 8 The component 230 according to a third exemplary embodiment is schematically shown. Similarly, the component 230 includes a non-conductive substrate 231 (e.g., made of an organic matrix composite material) and an anti-corrosion coating 232 deposited on the substrate 231.

[0169] In this third example, the anti-corrosion coating 232 comprises multiple stacked layers 233, more precisely, ten layers in this example, each layer having a thickness e. n The total coating thickness is 50 nm. t It is 500 nm.

[0170] In this third example, the anti-corrosion coating 232 comprises two types of alternately deposited layers 233: a main layer 233a made of a main material and a secondary layer 233b made of a secondary material. Here, the uppermost layer of the anti-corrosion coating 232 (exposed to the environment) is the main layer 233a.

[0171] In this third example, the main material, i.e., the material of the main layer 233a, is cubic tantalum nitride (TaN) doped with zirconium (Zr). In particular, this main material may correspond to the material of the anti-corrosion coating 32 of the first exemplary embodiment.

[0172] In this third example, the sub-material, namely the material of sub-layer 233b, is undoped hexagonal tantalum nitride (TaN).

[0173] This multi-layer anti-corrosion coating 232 can be used with... Figure 4 The same device 50, schematically shown and described in the context of the first exemplary embodiment, is deposited on the substrate 231. In practice, the primary layer 233a can be deposited by co-sputtering as described above; the secondary layer 233b can be deposited by high-power pulsed magnetron sputtering using only the first target 52, i.e., without applying power to the second target 53.

[0174] Therefore, it is possible to manufacture all layers 233 of coating 232 in a single step and with the aid of a single device 50 by controlling the polarization applied to each target 52, 53 over time.

[0175] Specifically, in this third example, the pressure in chamber 51 is fixed at 5 mTorr, approximately 0.7 Pa. The gas mixture consists of argon and nitrogen, containing 25 at% nitrogen. The primary layer is deposited using the same pulse parameters as in the first exemplary embodiment. The secondary layer is deposited using the following pulse parameters: pulse width equal to 50 µs; pulse frequency equal to 1000 Hz; pulse voltage equal to -700 V.

[0176] The corrosion resistance of the main material has been described in the context of the first exemplary embodiment.

[0177] Figure 9 The corrosion test results for the auxiliary material are described. The cyclic voltammetry test was performed under the same conditions as the test performed for the first exemplary embodiment, except that the working electrode was tested in several phosphoric acid baths with increasing concentrations: 0.1 mol / L; 0.5 mol / L; and 1 mol / L.

[0178] Therefore, the three curves 261, 262 and 263 correspond to the same working electrode, which is made of 316L stainless steel and completely covered with an undoped hexagonal tantalum nitride coating.

[0179] Curve 261 corresponds to a bath concentration of 0.1 mol / L. Curve 262 corresponds to a bath concentration of 0.5 mol / L. Curve 263 corresponds to a bath concentration of 1 mol / L.

[0180] like Figure 9 As shown, curves 261, 262, and 263 corresponding to the secondary material also have a significantly wider stability plateau than the curve of the 316L stainless steel reference material 231.

[0181] The test also measured the potential and corrosion current of 316L stainless steel (Table 3) and undoped hexagonal tantalum nitride (Table 4) at these different bath concentrations.

[0182] [Table 3]

[0183] [Table 4]

[0184] Therefore, the corrosion current I of undoped hexagonal tantalum nitride corr The rate of increase in acidity with increasing medium is much lower than that of 316L stainless steel, indicating that it has better corrosion resistance.

[0185] also, Figure 10 The microstructure (cross-sectional and front view) of a hexagonal tantalum nitride coating deposited using a high-power pulsed magnetron sputtering process according to this example is illustrated. The scale shown at the bottom of each view corresponds to 1 µm. From these two views, it can be seen that... Figure 6 Similar to the cubic counterpart in [the original text], the coating's microstructure is fine and uniform, implying good mechanical strength, particularly strong resistance to crack propagation within the coating. In contrast, such coatings deposited via conventional magnetron sputtering processes result in [the following is unclear and likely incomplete: "as in [the original text], the cubic counterpart in [the original text], the microstructure of the coating is fine and uniform, which means good mechanical strength, especially good resistance to crack propagation within the coating."] Figure 11 The columnar microstructure shown is easily broken.

[0186] Furthermore, the inventors determined that the cubic and hexagonal phases of tantalum nitride have significantly different Young's moduli. The Young's modulus of the cubic phase, measured by nanoindentation, is 430 GPa, while that of the hexagonal phase is 560 GPa.

[0187] Therefore, cracks tend to deflect at the interface between the main layer 233a and the sub-layer 233b. As a result, the stacking of multiple alternating main layers 233a and sub-layers 233b can significantly slow down crack propagation within the coating 232.

[0188] Finally, it is important to note that hexagonal tantalum nitride has a higher conductivity than cubic tantalum nitride, which further improves its conductivity. Therefore, the conductivity of hexagonal tantalum nitride deposited by high-power pulsed magnetron sputtering at 160°C is 4,045 S / cm.

[0189] In this third example, the main material is doped cubic tantalum nitride, while the secondary material is undoped hexagonal tantalum nitride. However, other multilayer configurations are also conceivable.

[0190] For example, the host material can be hexagonal tantalum nitride or dual-phase tantalum nitride (predominantly cubic or hexagonal). The host material can also contain different doping elements, or even one or more additional doping elements.

[0191] Similarly, for example, the secondary material can be doped. However, if the crystal system of the secondary material is the same as that of the primary material, the doping is preferably different from that of the primary material.

[0192] Therefore, particularly in the fourth exemplary embodiment, the coating comprises an alternating stack of doped hexagonal tantalum nitride layers and undoped hexagonal tantalum nitride layers.

[0193] In a fifth exemplary embodiment, the coating comprises an alternating stack of doped hexagonal tantalum nitride layers and doped or undoped cubic tantalum nitride layers.

[0194] Figure 12 The operation of the battery cell 520 under the context of the sixth exemplary embodiment is described precisely. In this sixth example, the fuel cell 501 is a direct methanol fuel cell (DMFC).

[0195] In this fuel cell 501, the fuel supplied to the anode 523 is methanol (CH3OH), while the fuel supplied to the cathode 525 is air. Liquid water (H2O) is also supplied to the anode 523.

[0196] Electrolyte 524 consists of a proton exchange membrane, which allows protons to exchange H+. + Through, while preventing electron e -The proton exchange membrane also prevents the passage of any gas. Platinum (optionally an alloy of nickel) is used as the catalyst in both the anode 523 and the cathode 525.

[0197] Therefore, anode 523 is the site of the following oxidation half-reaction: CH3OH + H2O → CO2 + 6H+ + + 6e - Then, cathode 525 is the site of the following reduction half-reaction: 4H + + 4e - + O2 → 2H2O Therefore, the overall operating equations for fuel cell 501 are as follows: 2CH3OH + 3O2 → 2CO2 + 4H2O In this proton exchange membrane battery, membrane 524 acts as the acidic electrolyte. It can be a Nafion (registered trademark) based membrane, which is a fluoropolymer copolymer based on sulfonated tetrafluoroethylene.

[0198] The end plates 511, 512 and / or bipolar plates 521, 527 of the fuel cell 501 can then be configured in a manner similar to the components described above; they can therefore include a non-conductive substrate and an anti-corrosion coating as described in any of the examples above. The anti-corrosion coating then protects the non-conductive substrate and performs the conductive function of the component.

[0199] Figure 13 The operation of the battery cell 20 is described in the context of another exemplary embodiment. In this example, the fuel cell 1 is an alkaline fuel cell.

[0200] In this fuel cell 1, the fuel supplied to the anode 23 is hydrogen (H2), while the fuel supplied to the cathode 25 is air.

[0201] Electrolyte 24 consists of an aqueous solution of potassium hydroxide (KOH), which allows hydroxide ions (OH-) to pass through the electrolyte. - Through, while preventing electron e - The electrolyte also prevents the passage of any gas. Due to the alkaline environment, non-precious metals can be selected as catalysts for the anode, such as iron, cobalt, or nickel. Silver or iron can be used as catalysts for the cathode.

[0202] Therefore, anode 23 is the site of the following oxidation half-reaction: 2H2 + 4OH - → 4H₂O + 2e - Then, cathode 25 is the site of the following reduction half-reaction: O2 + 2H2O + 4e - → 4OH - Therefore, the overall operating equations for fuel cell 1 are as follows: 2H₂ + O₂ → 2H₂O In this alkaline electrolyte battery, the electrolyte 24 is an aqueous solution, ensuring that water molecules (H2O) are always present at the cathode 25 to allow the reduction half-reaction to proceed. The oxidation half-reaction at the anode 23 replenishes the water molecules (H2O) consumed at the cathode 25, while simultaneously generating excess water, which is discharged through the diffusion layer 22.

[0203] Due to this highly corrosive environment, end plates 11 and 12 and bipolar plates 21 and 27 must be able to resist corrosion while continuing to perform their electrical conductivity function.

[0204] Figure 14 The operation of battery cell 20 is described in the context of another exemplary embodiment. In this example, fuel cell 1 is a solid oxide fuel cell (SOFC).

[0205] In this fuel cell 1, the fuel supplied to the anode 23 is hydrogen (H2), while the fuel supplied to the cathode 25 is air.

[0206] Electrolyte 24 is composed of yttrium oxide-stabilized zirconia (YSZ) ceramic, which allows O... 2- Ions pass through while preventing electrons from passing through. - Electrons pass through. This ceramic also prevents any gas from passing through. Due to the high operating temperature of this battery (over 500°C), precious metal catalysts (such as platinum) are not required; cheaper metals such as nickel or cobalt can be used.

[0207] Therefore, anode 23 is the site of the following oxidation half-reaction: H2 + O 2- → H2O + 2e - Then, cathode 25 is the site of the following reduction half-reaction: O2+ 4e - → 2 O 2- Therefore, the overall operating equations for fuel cell 1 are as follows: 2H₂ + O₂ → 2H₂O Due to this highly corrosive environment, end plates 11 and 12 and bipolar plates 21 and 27 must be able to resist corrosion while continuing to perform their electrical conductivity function.

[0208] Figure 15The operation of the battery cell 520 is described in the context of another exemplary embodiment. In this example, the fuel cell 501 is a molten carbonate fuel cell.

[0209] In this fuel cell 501, the fuel supplied to the anode 523 is hydrogen (H2), while the fuel supplied to the cathode 525 is air.

[0210] Electrolyte 524 consists of a molten mixture of lithium carbonate (Li₂CO₃) and potassium carbonate (K₂CO₃), forming a eutectic within a porous matrix of alumina and lithium. Electrolyte 524 enables CO₃²⁻ to... 2- Ions pass through while preventing electrons from passing through. - Electrons pass through. Electrolyte 524 also prevents the passage of any gases. Due to the high operating temperature of this battery (over 500°C), non-precious metals can be selected as catalysts.

[0211] Therefore, anode 523 is the site of the following oxidation half-reaction: H2 + CO3 2- → H2O + CO2 + 2e - Then, cathode 525 is the site of the following reduction half-reaction: O2 + 2CO2 + 4e - → 2CO3 2- Therefore, the overall operating equations for fuel cell 501 are as follows: 2H₂ + O₂ → 2H₂O Since the reduction half-reaction requires the consumption of carbon dioxide (CO2) at the cathode 525, while an equal amount of CO2 is produced by the oxidation half-reaction at the anode 523, a recirculation conduit 528 is provided between the two diffusion layers 522 and 526 to transport the CO2 produced at the anode 523 to the cathode 525. Additional CO2 can also be supplied externally as needed, particularly for starting the process.

[0212] The end plates 511, 512 and / or bipolar plates 521, 527 of the fuel cell 501 can then be configured in a manner similar to the components described above: they can therefore include a non-conductive substrate and an anti-corrosion coating as described in any of the examples above. The anti-corrosion coating then protects the non-conductive substrate and performs the conductive function of the component.

[0213] Although the invention has been described with reference to specific embodiments, it will be apparent that modifications and variations can be made to these examples without departing from the general scope of the invention as defined in the claims. In particular, various features shown or mentioned in the various embodiments can be combined to form other embodiments. Therefore, the specification and drawings should be regarded as exemplary rather than restrictive.

[0214] It is equally evident that all features described by the reference method can be transposed to the device individually or in combination, and conversely, all features described by the reference device can be transposed to the method individually or in combination.

Claims

1. An assembly for a fuel cell or electrolyzer having an acidic electrolyte, an alkaline electrolyte, a solid oxide electrolyte, or a molten salt, comprising: - Non-conductive substrate (31) and - An anti-corrosion coating (32) deposited on at least a portion of a surface of the substrate (31). The corrosion-resistant coating (32) includes at least one main layer based on tantalum nitride doped with one or more dopants selected from transition metals and / or lanthanides.

2. The component as claimed in claim 1, characterized in that, The substrate (31) is made of polymeric materials, particularly thermoplastics and / or elastomers.

3. The component as described in claim 1 or 2, characterized in that, The tantalum nitride in the main layer (32) has a hexagonal or cubic crystal system.

4. The component as claimed in any one of claims 1 to 3, characterized in that, The total dopant content in the main layer (32) is between 1 ppm and 10 at%, particularly between 10 ppm and 1 at%, and even more particularly between 0.2 and 0.5 at%.

5. The component as claimed in any one of claims 1 to 4, characterized in that, The main doping elements are selected from zirconium, hafnium, nickel, vanadium, titanium, niobium, chromium and / or molybdenum.

6. The component as claimed in any one of claims 1 to 5, characterized in that, The thickness of the anti-corrosion coating (32) is between 5 nm and 5 µm, particularly between 10 nm and 1 µm, and especially between 100 nm and 300 nm.

7. The component as claimed in any one of claims 1 to 6, characterized in that, The anti-corrosion coating (232) comprises multiple stacked layers (233a, 233b), particularly two to ten layers. The material of the main layer (233a) constitutes the main material, and The anti-corrosion coating (232) includes at least one sub-layer (233b) based on a sub-material that is different from the main material.

8. The component as claimed in claim 7, characterized in that, The main material accounts for at least 30% of the volume of the anti-corrosion coating, particularly at least 50%.

9. The component as claimed in claim 7 or 8, characterized in that, The anti-corrosion coating comprises alternating layers of the main material and layers of the secondary material.

10. The component as claimed in any one of claims 7 to 9, characterized in that, The secondary material is tantalum nitride having a different crystal system and / or being doped with a different material than the primary material.

11. An acidic electrolyte fuel cell or electrolyzer comprising at least one component (30) as claimed in any one of claims 1 to 10, particularly of the following types: - Proton exchange membrane fuel cell (PEMFC). - Phosphoric acid fuel cells (PAFCs), especially those supplied with gaseous fuels, particularly hydrogen (H2), - Direct methanol fuel cell (DMFC) - Direct ethanol fuel cells (DEFC), or - Direct glycol fuel cells (DEGFCs), specifically configured to be supplied with methanol (CH3OH), ethanol (C2H5OH), or ethylene glycol (HOC2H4OH).

12. An alkaline electrolyte fuel cell or electrolyzer comprising at least one component (30) as claimed in any one of claims 1 to 10, particularly of the following types: - Alkaline fuel cell (AFC). - Metal / air fuel cells, or - Direct urea fuel cell (DUFC).

13. A solid oxide fuel cell or electrolyzer comprising at least one component (30) as claimed in any one of claims 1 to 10, particularly of the following types: - Solid oxide fuel cell (SOFC) - Proton ceramic fuel cell (PCFC). - Molten carbonate fuel cell (MCFC) - Molten carbonate electrolyzer (MCEC) - Direct carbon fuel cells (DCFC), or - Direct urea fuel cell (DUFC).

Images