Catalyst Coating and Manufacturing Method

Abstract

A method of making a catalyst coated ion conducting membrane for an electrochemical cell is provided, the method including providing an ion conducting membrane, an electrocatalyst layer, and a masking layer between the ion conducting membrane and the electrocatalyst layer, the masking layer comprising one or more openings for providing one or more exposed areas and one or more unexposed areas of the electrocatalyst layer, and contacting the layers such that the one or more exposed areas of the electrocatalyst layer are transferred onto the ion conducting membrane and the masking layer prevents the one or more unexposed areas of the electrocatalyst layer from being transferred onto the ion conducting membrane.

Description

Technical Field

[0001] The present disclosure relates to components for an electrochemical cell and a method for manufacturing components for an electrochemical cell. In particular, the present disclosure relates to a masked electrocatalyst component and its manufacturing process, a process for producing a catalyst-coated ion-conductive membrane for use in an electrochemical cell such as a fuel cell or an electrolyzer, preferably a proton exchange membrane fuel cell or an electrolyzer, a catalyst-coated film produced by such a process, and a membrane electrode assembly including such a catalyst-coated ion-conductive membrane.

Background Art

[0002] A fuel cell is an electrochemical cell including two electrodes separated by an electrolyte. A fuel (e.g., hydrogen, an alcohol such as methanol or ethanol, or formic acid) is supplied to the anode, and an oxidant (e.g., oxygen or air) is supplied to the cathode. An electrochemical reaction occurs at the electrodes, converting the chemical energy of the fuel and the oxidant into electrical energy and heat. An electrolytic catalyst is used to facilitate the electrochemical oxidation of the fuel at the anode and the electrochemical reduction of oxygen at the cathode.

[0003] Fuel cells are typically classified according to the nature of the electrolyte used. In many cases, the electrolyte is a solid polymer membrane that is electronically insulating but ion-conductive. In a proton exchange membrane fuel cell, the ion-conductive membrane is proton-conductive, and protons generated at the anode are transported across the ion-conductive membrane to the cathode, where the protons combine with oxygen to form water.

[0004] The main component of a proton exchange membrane fuel cell is a membrane electrode assembly (MEA) composed of multiple layers. The central layer is a polymer ion-conducting membrane. On either side of the ion-conducting membrane is an electrocatalytic layer containing an electrocatalyst designed for a specific electrolytic reaction. This sandwich of the ion-conducting membrane and the electrocatalytic layer provides an electrochemically active surface. The electrocatalytic layer also generally contains a proton-conducting material, such as a proton-conducting polymer, to assist in the transfer of protons from the anode electrocatalyst to the ion-conducting membrane and / or from the ion-conducting membrane to the cathode electrocatalyst. Adjacent to each electrocatalytic layer is a gas diffusion layer. The gas diffusion layer needs to allow reactants to reach the electrocatalytic layer and needs to conduct the current generated by the electrochemical reaction. Therefore, the gas diffusion layer needs to be porous and conductive.

[0005] MEAs are generally fitted with sub-gaskets for use in fuel cells. In sub-gasketed MEAs, sub-gaskets are present on one or both sides of the polymer ion-conducting membrane. The sub-gaskets include openings that define the active area of ​​the MEA and are attached to the ion-conducting membrane or electrocatalytic layer using adhesive. These sub-gaskets are present to prevent gas leakage and may further include openings away from the active area that are aligned within the fuel cell stack to facilitate the porting of gases and liquids within the stack. A fuel cell stack can include a number of sub-gasketed MEAs, for example, along with flow field plates that are carefully aligned to avoid gas leakage, hydrogen crossover, and performance degradation. The power of the entire stack is proportional to the number of such joints in the stack. The performance of the stack depends, in part, on the integrity of the joints within the stack and between adjacent joints within the stack, various contacts, and sealing interfaces.

[0006] Conventional processes for manufacturing MEAs first require the production of a catalyst-coated ion-conductive film, which includes a polymer ion-conductive film placed between two electrocatalytic layers. This can be produced, for example, by a roll-to-roll process in which the electrocatalytic layers are transferred to each side of the ion-conductive film by a decal transfer process. A sub-gasket may be applied to the catalyst-coated ion-conductive film in a second roll-to-roll process. The gas diffusion layer is then bonded to the catalyst-coated ion-conductive film with the sub-gasket on the active area using an adhesive for bonding the gas diffusion layer to the catalyst-coated ion-conductive film with the sub-gasket. The adhesive may be a heat-soluble adhesive, in which case the parts are joined using a heated plate, either in a heated press or a custom-made equivalent machine. This allows the adhesive to flow and bond the parts together. The adhesive may also be a pressure-sensitive adhesive.

[0007] In the decal transfer process described above, the electrocatalytic layer is provided in roll-good form on a temporary carrier web that is peeled off after the electrocatalytic layer has been laminated onto a polymer ion-conductive film. The electrocatalyst is generally deposited or coated onto the temporary carrier web in the form of an ink or paste containing catalyst particles dispersed in an ionomer binder and / or solvent.

[0008] As those skilled in the art will understand, the same principles described above in relation to the manufacture of MEAs for fuel cells, in particular proton exchange membrane fuel cells, also apply to the manufacture of MEAs for electrolytic cells, in particular proton exchange membrane electrolytic cells. [Overview of the Initiative]

[0009] The present invention aims to provide an improved process for generating a catalyst-coated ion-conductive film, and typically a roll-good morphological electrocatalytic layer, by controlling the transfer of an electrocatalyst onto an ion-conductive film and reducing electrocatalyst consumption.

[0010] Method for manufacturing a catalyst coating film According to a first aspect of the present invention, a method is provided for producing a catalyst-coated ion-conducting membrane for an electrochemical cell such as a fuel cell or electrolytic cell, preferably a proton exchange membrane fuel cell or electrolytic cell, wherein the method is: The step of providing an ion-conductive film, an electrocatalytic layer, and a masking layer between the ion-conductive film and the electrocatalytic layer, wherein the masking layer has one or more openings for providing one or more exposed regions and one or more non-exposed regions of the electrocatalytic layer. The method includes the step of bringing the layers into contact such that one or more exposed regions of the electrocatalyst layer are transferred onto the ion-conducting film, and the masking layer prevents one or more non-exposed regions of the electrocatalyst layer from being transferred onto the ion-conducting film.

[0011] A first aspect of the present invention provides a printing masking process for transferring an electrocatalytic layer onto an ion-conducting film, such as a polymer electrolyte film, so that the electrocatalytic layer is transferred onto the ion-conducting film only in exposed regions corresponding to openings in the masking layer. The electrocatalytic layer in the non-exposed regions around the openings cannot be transferred to the ion-conducting film because it is physically separated from the ion-conducting film by the masking layer during lamination.

[0012] In conventional decal transfer processes, electrocatalytic decals are generally produced by coating or depositing an area of ​​electrocatalyst on a carrier web in the form of ink or paste. Such inks or pastes tend to flow to some extent, and therefore, it is difficult to control the precise dimensions of the electrocatalytic decal transferred onto the film during the decal transfer process. As a result, the electrocatalytic decal may be slightly larger than the area of ​​the film to be coated, which can cause problems with sealing the catalyst-coated ion-conductive film. On the other hand, the printing masking process of the present invention allows the dimensions of the electrocatalytic decal to be precisely controlled by openings in the masking layer, thereby mitigating such sealing problems, for example.

[0013] In some embodiments, the method further includes an initial step of providing a masking layer without openings, and a step of cutting openings into the masking layer, prior to the step of providing a masking layer between the ion-conducting film and the electrocatalyst layer. This makes it possible to control and customize the size and shape of the openings, and therefore the size and shape of the electrocatalyst decal, as needed. As will be understood by those skilled in the art, the size and shape of the openings are determined by the intended use of the catalyst-coated ion-conducting film. For example, the openings may be irregular or regular in shape, e.g., quadrilateral, e.g., substantially rectangular, or they may be substantially circular or elliptical. However, the size and shape of the openings are not limited. If there are two or more openings, the openings are preferably substantially the same shape and size.

[0014] In some embodiments, the step of bringing the layers into contact includes pressing the layers together. In some embodiments, the layers are pressed together between a pair of rollers in a roll-to-roll lamination process. Alternatively, the layers may be pressed together by a flatbed press or similar apparatus, which may be preferred in embodiments where the layers are provided as separate patches rather than as a continuous web.

[0015] In some embodiments, a roller or flatbed press heats the layers to temperatures including, for example, 100-200°C and 100-200°C. It will be understood that the exact lamination temperature depends on the materials used for the electrocatalytic layer and the ion-conducting film. The lamination temperature should be high enough to bond the electrocatalytic layer and the ion-conducting film to each other, but preferably not high enough to anneal or damage the layers.

[0016] In some embodiments, the method further includes, after the step of bringing the layers into contact, the step of removing the unexposed areas of the masking layer and the electrocatalyst layer from the ion-conducting film. The removal of the unexposed areas of the masking layer and the electrocatalyst layer can be facilitated, for example, by using a vacuum. Alternatively, in a roll-to-roll process, removal can be achieved by using a peeling bar or idler roller.

[0017] In some embodiments, the unexposed areas of the electrocatalytic layer are recovered and recycled for further use, thereby reducing waste of electrocatalytic material. For example, the recovered electrocatalyst can be recombined into an ink or paste to form a new electrocatalytic layer for use in the method of the first embodiment.

[0018] In some embodiments, electrocatalytic layers are provided on both sides of the ion-conducting film, and a masking layer is provided between the ion-conducting film and each respective electrocatalytic layer. In such embodiments, both sides of the ion-conducting film are simultaneously coated with the electrocatalyst, thereby improving the efficiency of the method.

[0019] In some embodiments, the ion-conducting film is sandwiched between two layers of non-ion-conducting sealing material, such that the film seal assembly comprises one or more inner regions and one or more boundary regions, the inner regions being ion-conducting and lacking the non-ion-conducting sealing material, and the boundary regions being non-ion-conducting and lacking the non-ion-conducting sealing material. Thus, the inner regions constitute the active area. The film seal assembly aims to reduce the waste of expensive film material by minimizing the amount of film material extending beyond the active area of ​​the catalyst-coated ion-conducting film, as described, for example, in the applicant's previous application, International Publication No. 2015 / 145129(A1). It will be understood that the exposed regions of the electrocatalyst layer are substantially aligned with the inner regions, and the masking layer is substantially aligned with the boundary region, so that the electrocatalyst layer is transferred onto the ion-conducting film, and the masking layer prevents one or more exposed regions of the electrocatalyst layer from being transferred onto the non-ion-conducting sealing material. The exposed area of ​​the electrocatalyst layer is larger than the area of ​​the inner region of the film seal assembly, which is advantageous in that it compensates for the step created by the non-ionic conductive sealing material and ensures that the ion-conducting film is completely covered and not left exposed during the transfer of the electrocatalyst layer. However, it is undesirable to transfer a substantial amount of the electrocatalyst layer onto the non-ionic conductive sealing material, and therefore, typically, the area of ​​the exposed region is not large enough to facilitate the transfer of the electrocatalyst layer onto the non-ionic conductive sealing material. Typically, the exposed area of ​​the electrocatalyst layer is larger than the area of ​​the inner region of the film seal assembly, and as a result, the exposed area of ​​the electrocatalyst layer forms a frame around the inner region of the ion-conducting film with a width of up to 2 mm, typically 1 mm or more.

[0020] In some embodiments, the ion-conducting membrane includes a polymer electrolyte membrane. Types of polymer electrolyte membranes suitable for use in electrochemical cells, preferably such as fuel cells or electrolytic cells, including proton exchange membrane fuel cells or electrolytic cells, are known to those skilled in the art and may include proton-conducting polymers or anion-conducting polymers, such as hydroxyl anion-conducting polymers. Examples of suitable proton-conducting polymers include perfluorosulfonic acid ionomers (e.g., ionomers based on sulfonated hydrocarbons, such as Nafion® (EIDuPont de Nemours and Co.), Aciplex® (Asahi Kasei), Aquivion® (Solvay Speciality Polymers), Flemion® (Asahi Glass Co.), or Fumapem® P, E, or K series products available from FuMA-Tech GmbH, JSR Corporation, Toyobo Corporation, etc. Examples of suitable anion-conducting polymers include A901 manufactured by Tokuyama Corporation and Fumasep FAA manufactured by FuMA-Tech GmbH.

[0021] Similarly, types of electrocatalysts suitable for use in electrochemical cells are known to those skilled in the art. For example, the electrocatalyst layer may be the cathode or anode electrocatalyst layer of a fuel cell or electrolytic cell, preferably a proton exchange membrane fuel cell or electrolytic cell. For example, the electrocatalyst may contain platinum group metals, namely ruthenium, rhodium, palladium, osmium, iridium, or platinum, or alloys of platinum group metals.

[0022] The electrocatalyst layer preferably contains an ion-conducting polymer, such as a proton-conducting ionomer, to improve the ion conductivity of the layer. Therefore, the ion-conducting material may include ionomers such as perfluorosulfonic acid (e.g., perfluorosulfonic acid ionomer materials from Nafion® (Chemours Company), Aciplex® (Asahi Kasei), Aquivion® (Solvay Specialty Polymer), Flemion® (Asahi Glass Co.), and 3M®), or ionomers based on partially fluorinated or non-fluorinated hydrocarbons, such as those available from FuMA-Tech GmbH as products in the fumapem® P, E, or K series, as well as those available from JSR, Toyobo, and other companies. Preferably, the ionomer is a perfluorosulfonic acid, particularly the Nafion® series available from Chemours, especially Nafion® 1100EW, and the Aquivion® series available from Solvay, especially Solvay® 830EW.

[0023] In some embodiments, the masking layer comprises a polymer film. Preferably, the polymer film comprises a polymer that is thermally stable at the temperature used to laminate the layer in order to prevent contamination of the catalyst-coated ion-conductive film by the masking layer. Therefore, in some embodiments, the polymer film comprises a polymer that is thermally stable at temperatures in the range of 100 to 200°C and including temperatures within 100 to 200°C. In some embodiments, the polymer film is made of polyetherimide, polyimide (PI), polyethersulfone (PES), fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), Viton®, polyethylene oxide (PEO), polyphenylene ether (PPE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyacrylonitrile (PAN), poly(p-phenylene sulfide) (PPS), polyolefins, and silicones, preferably polyethylene naphthalate (PEN), polyethyleneimine (PEI), polyether ether ketone (PEEK), and polyphenylene sulfide (polyphenylene The masking layer may include sulfide (PPS), polytetrafluoroethylene (PTFE), or mixtures thereof. The masking layer may be printed on the electrocatalytic layer, for example, using inkjet or gravure printing. Any printable polymer that is thermally stable at the temperature used to laminate the layers can be used. Printing the masking layer allows for an even higher level of precision, including a thickness profile in addition to the masking layer itself.Suitably, a polymer having a precursor that does not require a solvent for incorporation into a printable ink, such as a UV-curable polymer, can be used.

[0024] In some embodiments, the ion-conductive membrane, the electrocatalytic layer, and the masking layer are each provided separately. For example, separate webs of the ion-conductive membrane, the electrocatalytic layer, and the masking layer can be simultaneously fed between a pair of laminating rollers in a roll-to-roll process.

[0025] In other embodiments, the electrocatalytic layer and the masking layer are provided together as a pre-formed masked electrocatalytic component. Preferably, the masking layer is bonded to the electrocatalytic layer. In some such embodiments, the masking layer is bonded to the electrocatalytic layer by an adhesive. Preferably, the adhesive is thermally stable at the temperature used to laminate the layers to prevent contamination of the catalyst-coated ion-conductive membrane by the adhesive. Thus, in some embodiments, the adhesive is thermally stable at temperatures in the range of 100 - 200 °C and including 100 - 200 °C. In some embodiments, the adhesive includes a pressure-sensitive adhesive such as a silicone pressure-sensitive adhesive.

[0026] The pre-formed masked electrocatalytic component can be provided as a continuous web for a roll-to-roll process or as separate patches for an individual assembly process.

[0027] In some embodiments, the method further includes applying a sub-gasket around the active area of the catalyst-coated ion-conductive membrane. For example, the catalyst-coated ion-conductive membrane can be laminated between two half-sub-gasket layers that are bonded to the catalyst-coated ion-conductive membrane by an adhesive. The sub-gasket can be applied to the catalyst-coated ion-conductive membrane in a roll-to-roll lamination process.

[0028] According to a second aspect of the present disclosure, a catalyst-coated ion-conductive membrane produced by the method of the first aspect is provided.

[0029] According to a third aspect of the present invention, there is provided a membrane electrode assembly comprising the catalyst-coated ion-conductive membrane of the second aspect. The membrane electrode assembly includes a gas diffusion layer adjacent to each of the electrocatalyst layers.

[0030] According to a fourth aspect of the present invention, there is provided a fuel cell, preferably a proton exchange membrane fuel cell, comprising the catalyst-coated ion-conductive membrane of the second aspect or the membrane electrode assembly of the third aspect.

[0031] According to a fifth aspect of the present invention, there is provided an electrolytic cell, preferably a proton exchange membrane electrolytic cell, comprising the catalyst-coated ion-conductive membrane of the second aspect or the membrane electrode assembly of the third aspect.

[0032] Method for producing a masked electrocatalyst component According to a sixth aspect of the present invention, there is provided a method for generating a masked electrocatalyst component for use in the production of a catalyst-coated ion-conductive membrane. The method comprises providing an electrocatalyst layer, and providing a masking component comprising a masking layer, the masking layer comprising one or more openings, and combining the masking layer with the electrocatalyst layer to form a masked electrocatalyst component.

[0033] Suitable materials for the electrocatalyst layer and the masking layer are as described in relation to the first aspect. For example, in some embodiments, the electrocatalyst layer comprises a platinum group metal or an alloy of a platinum group metal.

[0034] Preferably, the step of combining the masking layer with the electrocatalyst layer to form a masked electrocatalyst component is a step of joining the masking layer to the electrocatalyst layer to form a masked electrocatalyst component. In some embodiments, the step of joining the masking layer to the electrocatalyst layer is carried out by a roll-to-roll lamination process, and the layers are pressed together between a pair of rollers.

[0035] In some embodiments, the electrocatalytic layer is supported on a temporary carrier layer. The carrier layer helps protect the electrocatalytic layer and allows the masked electrocatalytic components to be wound onto a roll. The carrier layer may be removed before the masked electrocatalytic components are used in the process to produce a catalyst-coated ion-conductive film. The temporary carrier may be formed from any suitable material that can be removed without damaging the electrocatalytic layer and can maintain mechanical strength / integrity at high temperatures, e.g., up to 200°C. Examples of suitable materials include fluoropolymers, e.g., polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene propylene (FEP - copolymer of hexafluoropropylene and tetrafluoroethylene), polyolefins (e.g., biaxially oriented polypropylene (BOPP)), and polyethylene terephthalate (PET).

[0036] Preferably, the masking layer is bonded to the electrocatalyst layer by an adhesive. In such embodiments, the layers may or may not require heating to bond the masking layer to the electrocatalyst layer. However, the masked electrocatalyst components may be heated during the manufacturing process of the catalyst-coated ion-conducting film, for example, in the method according to the first embodiment, when the electrocatalyst layer is laminated onto the ion-conducting film. Therefore, in some embodiments, the adhesive is thermally stable at temperatures including 100-200°C and 100-200°C to ensure that the adhesive does not contaminate the active area during the lamination of the catalyst-coated ion-conducting film. In some embodiments, the adhesive includes a pressure-sensitive adhesive such as a silicone pressure-sensitive adhesive.

[0037] In some embodiments, the masking component further comprises a reinforcing layer for stabilizing the masking layer during the step of bonding the masking layer to the electrocatalyst layer. The masking layer is typically about 10–30 μm thick, preferably 10–20 μm, and more preferably 10–15 μm thick, and thus the reinforcing layer provides structural stability to prevent deformation of the masking layer (particularly the shape of the openings) while the masking layer is in contact with the electrocatalyst layer.

[0038] The reinforcing film may include any material that can maintain mechanical strength / integrity during the process. In some embodiments, the reinforcing layer includes a reinforcing polymer film. Since the reinforcing material is typically removed before high temperatures are applied, it is preferable that the material does not need to be stable at high temperatures. Therefore, the material can be low-cost and mechanically robust. In some embodiments, the reinforcing polymer film includes polyethyleneimine (PEI), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyimide (PI), and polyethylene terephthalate (PET). PET has the advantages of being low-cost and mechanically robust. In some embodiments, the reinforcing layer is bonded to the masking material by an adhesive. In embodiments where an adhesive is used to bond each layer together, the adhesive used to bond the reinforcing layer to the masking layer should be weaker than the adhesive used to bond the masking layer to the electrocatalytic layer to ensure that the masking layer does not separate from the electrocatalytic layer when the reinforcing layer is removed. In other words, the adhesive used to bond the reinforcing layer to the masking layer must be less tacky than the adhesive used to bond the masking layer to the electrocatalytic layer.

[0039] In some embodiments, the method further includes the step of removing a reinforcing layer after the step of combining the masking layer with the electrocatalytic layer, thereby minimizing the thickness of the masking components. The reinforcing layer can be removed by any preferred means, for example, by a peeling bar or idler roller in a continuous roll-to-roll process, or by the use of vacuum.

[0040] In some embodiments, the electrocatalytic layer and the masking component are each provided in the form of a continuous web, and the masking layer has a plurality of openings along the length of the web. In some such embodiments, if the masked electrocatalytic component is produced in the form of a continuous web, the masked electrocatalytic component may be wound onto a roll or used directly in a further process for producing a catalyst-coated ion-conductive film.

[0041] Alternatively, in some embodiments, the method further includes the step of cutting the masked electrocatalytic component into separate patches. In some such embodiments, the masked electrocatalytic component is cut between openings in the masking layer such that the masking layer within each patch has a single opening. The patches can then be used to form individual catalyst-coated ion-conductive films in a non-roll-to-roll process.

[0042] In some embodiments, the method further includes the step of cutting alignment features into masked electrocatalytic components to help align the masked electrocatalytic components during the process of manufacturing a catalyst-coated ion-conductive film. During the process of manufacturing the catalyst-coated ion-conductive film, the alignment features in the masked electrocatalytic components may be aligned with corresponding alignment features in the ion-conductive layer or film, enabling the electrocatalytic layer to be precisely positioned on the film.

[0043] According to a seventh aspect of the present invention, a masked electrocatalytic component produced by the method of the sixth aspect is provided. The masked electrocatalytic component of the seventh aspect may be used in the method of the first aspect.

[0044] Masked electrocatalytic components According to an eighth aspect of the present invention, a masked electrocatalytic component is provided for use in the manufacture of an electrochemical cell such as a fuel cell or electrolytic cell, preferably a proton exchange membrane fuel cell or electrolytic cell. The masked electrocatalytic component is An electrocatalytic layer having a first surface and a second surface located on the opposite side, The electrocatalyst layer comprises a masking layer disposed on the first surface of the electrocatalyst layer, The masking layer has one or more openings, thereby providing one or more exposed regions and one or more non-exposed regions of the first surface of the electrocatalyst layer.

[0045] As described above in relation to the first embodiment, one or more exposed regions of the electrocatalyst layer correspond to one or more openings in the masking layer, while one or more non-exposed regions of the electrocatalyst layer remain covered under the masking layer around the openings. Preferably, there are two or more openings, thereby providing two or more exposed regions and two or more non-exposed regions. The size and shape of the openings are determined by the intended use of the electrochemical cell. For example, the openings may be irregular or regular in shape, e.g., quadrilateral, e.g., substantially rectangular, or they may be substantially circular or elliptical. However, the size and shape of the openings are not limited. If there are two or more openings, they are preferably substantially the same shape and size.

[0046] In some embodiments, the masked electrocatalytic component is in the form of a continuous web (also known as a rollgood configuration), where the electrocatalytic layer and the masking layer are each a continuous web, and the masking layer has a plurality of openings along the length of the web, thereby providing a plurality of exposed and unexposed areas on the first surface of the electrocatalytic layer. The openings may be spaced at regular intervals along the web. The rollgood configuration masked electrocatalytic component may be wound on a roll, thereby forming a rollgood assembly.

[0047] In other embodiments, the masked electrocatalytic component is in the form of a separate patch, which can be used in the production of individual catalyst-coated ion-conductive films. In some such embodiments, the masking layer has a single opening, thereby providing one exposed region and one unexposed region of the first surface of the electrocatalytic layer. This facilitates the transfer of the single exposed region of the electrocatalytic layer onto the film during the process of producing the catalyst-coated ion-conductive film.

[0048] In some embodiments, the masked electrocatalytic component further comprises a carrier layer disposed on a second surface of the electrocatalytic layer. The carrier layer helps to support and protect the electrocatalytic layer and allows a continuous web of the masked electrocatalytic component to be wound onto a roll. Examples of suitable carrier materials include fluoropolymers, e.g., polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), perfluoroalkoxy polymers (PFA), fluorinated ethylene propylene (FEP - copolymer of hexafluoropropylene and tetrafluoroethylene), polyolefins (e.g., biaxially oriented polypropylene (BOPP)), and polyethylene terephthalate (PET).

[0049] Suitable materials for use in the electrocatalytic layer and the masking layer are as described in relation to the first embodiment. For example, in some embodiments, the electrocatalytic layer comprises a platinum group metal or an alloy of a platinum group metal.

[0050] In some embodiments, the masking layer is bonded to the electrocatalyst layer by an adhesive. Preferably, the adhesive is thermally stable at the lamination temperature used in the process for manufacturing the catalyst-coated ion-conductive film in order to prevent contamination of the catalyst-coated ion-conductive film by the adhesive. Therefore, in some embodiments, the adhesive is thermally stable at temperatures in the range of 100-200°C and including 100-200°C. In some embodiments, the adhesive includes a pressure-sensitive adhesive such as a silicone pressure-sensitive adhesive.

[0051] In some embodiments, the masked electrocatalytic component includes alignment features to help align the masked electrocatalytic component during a process to manufacture a catalyst-coated ion-conductive film according to a first aspect of the present invention. During the process of manufacturing the catalyst-coated ion-conductive film, the alignment features in the masked electrocatalytic component may be aligned with corresponding alignment features in the ion-conductive layer, enabling the electrocatalytic layer to be precisely positioned on the ion-conductive film. The alignment features may be openings cut into the masking layer or the masking layer and the electrocatalytic layer, such as holes, notches, slots, or grooves. Alternatively, the alignment features may be visible marks fabricated on the masking layer or the masking layer and the electrocatalytic layer, which can be detected by a visual system for alignment.

[0052] A masked electrocatalytic component of the eighth embodiment may be used in the method of the first embodiment.

[0053] It will be understood that any feature described in relation to the first, second, third, sixth, seventh, or eighth aspect may be freely combined with any other aspect as appropriate. [Brief explanation of the drawing]

[0054] Embodiments of the present invention will be described in more detail with reference to the following drawings. These are illustrative and not limiting to the present invention. [Figure 1] This is a perspective view of a masked electrocatalytic component according to an embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view of a masked electrocatalytic component. [Figure 3] This is a perspective view of a masked electrocatalytic component according to an embodiment of the present invention. [Figure 4] Figure 3 is a cross-sectional view of a masked electrocatalytic component. [Figure 5] This is a process flow diagram illustrating a method for producing a catalyst-coated ion-conductive film according to an embodiment of the present invention. [Figure 6] This is a process flow diagram illustrating a method for producing a catalyst-coated ion-conductive film according to an embodiment of the present invention. [Figure 7] This shows a catalyst-coated ion-conducting film manufactured by a roll-to-roll process according to an aspect of the present invention. [Figure 8] This is a process flow diagram illustrating a method for manufacturing a masked electrocatalytic component according to one embodiment of the present invention. [Figure 9] This is a process flow diagram illustrating a method for producing a masked electrocatalytic compound according to one embodiment of the present invention. [Figure 10A] This document shows a subsystem of a roll-to-roll based system for producing masked electrocatalytic components by the method of the present invention. [Figure 10B] This document shows a subsystem of a roll-to-roll based system for producing masked electrocatalytic components by the method of the present invention. [Modes for carrying out the invention]

[0055] Figures 1 and 2 show a masked electrocatalytic component 100 according to one embodiment of the present invention. In the shown embodiment, the masked electrocatalytic component 100 is in the form of separate patches for use in the production of individual catalyst-coated ion-conductive films.

[0056] The masked electrocatalytic component 100 comprises an electrocatalytic layer 2 having a first surface 4 and a second surface 6 located on the opposite side. The masked electrocatalytic component 100 further comprises a masking layer 8 located on the first surface 4 of the electrocatalytic layer 2. The masking layer 8 includes an opening 10 that exposes a region of the electrocatalytic layer 2 located beneath the masking layer 8. The region of the electrocatalytic layer 2 corresponding to the opening 10 can be called the exposed region 12, while the region of the electrocatalytic layer 2 remaining beneath the masking layer 8 around the opening 10 can be called the unexposed region 14. In the illustrated embodiment, the masking layer 8 is bonded to the electrocatalytic layer 2 by an adhesive layer 16. This is preferred as it facilitates easier handling of the masked electrocatalytic component.

[0057] Figures 3 and 4 show a masked electrocatalytic component 200 according to another embodiment of the present invention, which is in the form of a continuous web (which can be used in rollgoods) rather than separate patches. The same reference numerals are used for components that are common between the embodiments shown in Figures 1 and 2 and the embodiments shown in Figures 3 and 4.

[0058] In the illustrated embodiment, the carrier layer 18 is provided adjacent to the second surface 6 of the electrocatalyst layer 2 and helps to support and protect the electrocatalyst layer 2. The masking layer 8 is provided as a continuous web with a plurality of openings 10, thereby forming a plurality of exposed regions 12 of the electrocatalyst layer 2.

[0059] In the illustrated embodiment, alignment features 20 are provided to assist in aligning a masked electrocatalytic component 200 with the ion-conducting film during the manufacturing of a catalyst-coated ion-conducting film. The alignment features 20 are notches cut into the masked electrocatalytic component 200. The alignment features 20 can also assist in aligning with a second masked electrocatalytic component if two such components are applied to the ion-conducting film simultaneously.

[0060] Figure 5 shows a flowchart of a method for producing a catalyst-coated ion-conductive film according to an embodiment of the present invention. In the first step, an ion-conductive film, an electrocatalytic layer, and a masking layer between the ion-conductive film and the electrocatalytic layer are provided (306). The masking layer has one or more openings to provide one or more exposed regions and one or more non-exposed regions of the electrocatalytic layer. In the second step, the layers are brought into contact (308), so that one or more exposed regions of the electrocatalytic layer are transferred onto the ion-conductive film, and the masking layer prevents one or more non-exposed regions of the electrocatalytic layer from being transferred onto the ion-conductive film.

[0061] Therefore, an electrocatalytic decal corresponding to the openings in the masking layer is transferred onto the ion-conducting film, which allows for precise control of the exact size and shape of the electrocatalytic decal by modifying the size and shape of the openings in the masking layer. The result is a catalyst-coated ion-conducting film with a very precisely defined electrocatalytic layer that does not extend beyond the intended active area to an undesirable distance.

[0062] Preferably, step 308, which brings the layers into contact, includes pressing the layers together. The layers may be pressed together between a pair of rollers in a roll-to-roll lamination process or between two plates in a flatbed press. The rollers or flatbed press may heat the layers to temperatures including 100-200°C and 100-200°C to help adhere the electrocatalytic decal to the ion-conductive film without the need to use separate adhesives.

[0063] Figure 6 shows a flow diagram of a method for producing a catalyst-coated ion-conductive film according to another embodiment of the present invention. A masking layer is first provided (302), and openings are cut into the masking layer (304). The size and shape of the openings can be adjusted to suit the requirements of the electrocatalytic layer in the catalyst-coated ion-conductive film.

[0064] Next, an ion-conductive film, an electrocatalytic layer, and a masking layer are provided (306), the masking layer being provided between the ion-conductive film and the electrocatalytic layer. One or more openings in the masking layer provide one or more exposed regions and one or more non-exposed regions of the electrocatalytic layer.

[0065] Next, the layers are brought into contact (308), so that one or more exposed areas of the electrocatalytic layer are transferred onto the ion-conducting film, and the masking layer prevents one or more unexposed areas of the electrocatalytic layer from being transferred onto the ion-conducting film. As previously stated, bringing the layers into contact 308 may include pressing the layers together. The layers may be pressed together between a pair of rollers in a roll-to-roll lamination process or between two plates of a flatbed press, and the rollers or flatbed press may heat the layers to temperatures in the range of 100-200°C and including 100-200°C.

[0066] In the next step, the unexposed areas of the masking layer and the electrocatalyst layer are removed from the ion-conducting film (310), leaving only the electrocatalyst decal on the ion-conducting layer. The unexposed areas of the electrocatalyst layer are then recovered and can be recycled for further use, for example, in a new electrocatalyst layer provided at the start of the process (306) (312).

[0067] As shown in Figure 7 illustrating a roll-to-roll process for producing a catalyst-coated ion-conductive film according to the present invention, the electrocatalyst layer 2 (shown as being positioned on a carrier layer or backing liner 18) may be provided on both sides of the ion-conductive film 22, and the masking layer 8 is positioned between the ion-conductive film 22 and each respective electrocatalyst layer 2.

[0068] The layers are supplied simultaneously between a pair of laminating rollers 24, which laminate the layers and transfer the exposed regions 12 of the electrocatalyst layer 2 (corresponding to the openings 10 of the masking layer 8) onto the ion-conducting film 22. Next, the masking layer 8 and the unexposed regions 14 of the electrocatalyst layer 2 (along with the backing liner 18) are peeled off from the ion-conducting film 22, leaving the exposed regions 12 of the electrocatalyst layer on the ion-conducting film 22 as an electrocatalyst decal. In the roll-to-roll process shown, each layer is supplied as a continuous web, and as a result, the resulting catalyst-coated ion-conducting film is also produced in the form of a continuous web, i.e., in roll-good form. The catalyst-coated ion-conducting film may then be used directly in a roll-to-roll process for manufacturing a film electrode assembly, or it may be wound onto a roll for future use.

[0069] Therefore, the process of the present invention can provide a highly efficient process for producing a rollgood-type catalyst-coated ion-conductive film having precisely defined electrocatalytic decals.

[0070] Although the masking layer 8 and the electrocatalytic layer 2 are shown as separate layers provided between the rollers 24, they may also be provided joined together as a pre-formed masked electrocatalytic component.

[0071] Figure 8 shows a flowchart of a method for producing a masked electrocatalytic component according to one embodiment of the present invention. First, an electrocatalytic layer is provided (402), and a masking component comprising a masking layer is provided (404). Next, the masking layer is bonded to the electrocatalytic layer to form a masked electrocatalytic component (406). Bonding is not required, but is preferred because it facilitates easier handling of the masked electrocatalytic material. The masking layer and the electrocatalytic layer may be bonded by, for example, an adhesive. The adhesive should preferably be thermally stable at the lamination temperature used in the process for producing the catalyst-coated ion-conductive film. For example, the adhesive may be a silicone pressure-sensitive adhesive.

[0072] Figure 9 shows a flowchart of a method for producing a masked electrocatalytic component according to another embodiment of the present invention. An electrocatalytic layer is provided (402), and a masking component comprising a masking layer and a reinforcing layer is provided (403). The reinforcing layer helps to stabilize the masking layer and maintain its shape while in contact with the electrocatalytic layer. The reinforcing layer can be removed from the masking component (405) before bonding the masking layer to the electrocatalytic layer (406). Aligned features can then be cut into the masked electrocatalytic component (410).

[0073] Removing the reinforcing layer is not mandatory, but it helps minimize the thickness of the masking components during the process of manufacturing the catalyst-coated ion-conductive film. Removing the reinforcing layer also means that the reinforcing layer can be made from a polymer that does not need to be thermally stable at the lamination temperature used during the process of manufacturing the catalyst-coated ion-conductive film.

[0074] Figures 10A and 10B show model subsystems of a roll-to-roll based system for manufacturing masked electrocatalytic components according to embodiments of the present invention.

[0075] A masking component 60, comprising a masking layer and a reinforcing layer, is supplied to a rotary die cutter 62 that cuts an opening in the masking layer. A protective layer 64 covering the adhesive pre-applied on the masking layer is also removed at this point. At this time, the masking component with the opening in the masking layer is gently placed on the electrocatalyst layer 2. The masking component and the electrocatalyst layer are laminated together between rollers 66. Next, the reinforcing layer 68 is peeled off from the masking layer by a peeling bar 70, leaving a masked electrocatalyst component 72 comprising the masking layer and the electrocatalyst layer.

[0076] The aligned feature portion can be cut into the masked electrocatalytic component by a rotary die cutter 74. The masked catalyst component may then be wound onto a roll 76 for later use if it is not directly provided for the process of producing a catalyst-coated ion-conductive film.

[0077] It will be understood that the drawings used herein to illustrate embodiments of the present invention are not drawn to exact scale and are provided purely for the purpose of aiding the understanding of the invention.

Claims

1. A method for producing a catalyst-coated ion-conducting film for an electrochemical cell, wherein the method is The steps of providing an ion-conductive film, an electrocatalytic layer, and a masking layer between the ion-conductive film and the electrocatalytic layer, wherein the masking layer has one or more openings for providing one or more exposed regions and one or more non-exposed regions of the electrocatalytic layer. The step of bringing the layers into contact such that one or more exposed regions of the electrocatalyst layer are transferred onto the ion-conducting film, and the masking layer prevents one or more non-exposed regions of the electrocatalyst layer from being transferred onto the ion-conducting film, A method comprising providing the electrocatalytic layer and the masking layer together as a pre-formed masked electrocatalytic component, wherein the masking layer is bonded to the electrocatalytic layer.

2. The method according to claim 1, further comprising: an initial step of providing a masking layer without openings before the step of providing the masking layer between the ion-conducting film and the electrocatalyst layer; and a step of cutting the openings into the masking layer.

3. The method according to claim 1, wherein the step of bringing the layers into contact includes pressing the layers together.

4. The method according to claim 3, wherein the layer is pressed together between a pair of rollers in a roll-to-roll lamination process.

5. The method according to claim 3, wherein the layers are pressed together by a flatbed press.

6. The method according to claim 4 or 5, wherein the roller or the flatbed press heats the layer to a temperature in the range of 100 to 200°C and including 100 to 200°C.

7. The method according to any one of claims 1 to 5, further comprising the step of removing the masking layer and the unexposed region of the electrocatalyst layer from the ion-conducting film after the step of bringing the layers into contact.

8. The method according to claim 7, wherein the unexposed region of the electrocatalyst layer is recovered and recycled for further use.

9. The method according to any one of claims 1 to 5, wherein an electrocatalytic layer is provided on both sides of the ion-conducting film, and a masking layer is provided between the ion-conducting film and each respective electrocatalytic layer.

10. The method according to any one of claims 1 to 5, wherein the ion-conducting film is sandwiched between two layers of non-ion-conducting sealing material so as to be a film seal assembly, and the film seal assembly comprises one or more inner regions and one or more boundary regions, the inner regions lacking non-ion-conducting sealing material and being ion-conductive, and the boundary regions comprising the non-ion-conducting sealing material and being non-ion-conductive.

11. The method according to any one of claims 1 to 5, wherein the ion-conducting membrane includes a polymer electrolyte membrane.

12. The method according to any one of claims 1 to 5, further comprising the step of applying a sub-gasket around the active area of ​​the catalyst-coated ion-conductive film.

13. A method for producing a masked electrocatalytic component for use in the production of a catalyst-coated ion-conducting film, wherein the method is The steps include providing an electrocatalytic layer, A masking component comprising a masking layer, wherein the masking layer comprises one or more openings; The process includes the step of combining the masking layer with the electrocatalytic layer to form a masked electrocatalytic component, (i) The step of combining the masking layer with the electrocatalytic layer to form a masked electrocatalytic component is the step of bonding the masking layer to the electrocatalytic layer to form a masked electrocatalytic component, and / or (ii) The masking component further comprises a reinforcing layer for stabilizing the masking layer during the step of combining the masking layer with the electrocatalyst layer, and / or (iii) A method further comprising the step of cutting alignment features into the masked electrocatalytic components in order to help align the masked electrocatalytic components during the process of manufacturing a catalyst-coated ion-conductive film.

14. The method according to claim 13, wherein the step of bonding the masking layer to the electrocatalyst layer is carried out by a roll-to-roll lamination process, and the layers are pressed together between a pair of rollers.

15. The method according to claim 13 or 14, wherein the masking layer is bonded to the electrocatalyst layer by an adhesive.

16. The method according to claim 13, wherein the reinforcing layer includes a reinforcing polymer film.

17. The method according to claim 13, wherein the reinforcing layer is bonded to the masking material by an adhesive.

18. The method according to claim 13, further comprising the step of removing the reinforcing layer after the step of bonding the masking layer to the electrocatalyst layer.

19. The method according to claim 13 or 14, wherein the electrocatalytic layer and the masking component are each provided in the form of a continuous web, and the masking layer has a plurality of openings along the length of the web.

20. The method according to claim 19, further comprising the step of generating the masked electrocatalytic component in the form of a continuous web and cutting the masked electrocatalytic component into separate patches.

21. The method according to claim 20, wherein the masked electrocatalytic component is cut between openings in the masking layer such that the masking layer in each patch has a single opening.

22. A masked electrocatalytic component for use in the manufacture of an electrochemical cell, wherein the masked electrocatalytic component is An electrocatalytic layer having a first surface and a second surface located on the opposite side, The electrocatalyst layer comprises a masking layer disposed on a first surface of the electrocatalyst layer, The masking layer comprises one or more openings, thereby providing one or more exposed areas and one or more non-exposed areas of the first surface of the electrocatalyst layer. (i) further comprising a carrier layer disposed on the second surface of the electrocatalyst layer, and / or (ii) A masked electrocatalytic component in which the masking layer is bonded to the electrocatalytic layer by an adhesive.

23. The masked electrocatalytic component according to claim 22, wherein the masked electrocatalytic component is in a rollgood configuration, the electrocatalytic layer and the masking layer are each continuous webs, and the masking layer has a plurality of openings along the length of the web.

24. The masked electrocatalytic component according to claim 22, wherein the masked electrocatalytic component is in the form of a separate patch.

25. The masked electrocatalytic component according to claim 24, wherein the masking layer comprises a single opening.

26. The masked electrocatalytic component according to any one of claims 22 to 25, wherein the electrocatalytic layer comprises a platinum group metal or an alloy of a platinum group metal.

27. The masked electrocatalytic component according to any one of claims 22 to 25, wherein the masking layer includes a polymer film.

28. The masked electrocatalytic component according to claim 27, wherein the polymer film comprises a polymer that is thermally stable at temperatures in the range of 100 to 200°C and including 100 to 200°C.

29. The masked electrocatalytic component according to claim 27, wherein the polymer film comprises polyethylene naphthalate (PEN), polyethyleneimine (PEI), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyimide (PI), polytetrafluoroethylene (PTFE), or a mixture thereof.

30. The masked electrocatalytic component according to claim 22, wherein the adhesive is thermally stable at temperatures in the range of 100 to 200°C and including 100 to 200°C.

31. The masked electrocatalytic component according to claim 22, wherein the adhesive comprises a silicone pressure-sensitive adhesive.

Images