JP2006512746A - Manufacturing method supported on substrate of microfibrous fuel cell - Google Patents

Abstract

The present invention relates to a continuous, automated, substrate-supported manufacturing method for microfibrous fuel cells and other electrochemical devices. Specifically, a removable substrate layer (92) is formed around the internal current collector (82), followed by a number of structure layers in turn on the removable substrate layer (92), For example, coating the inner catalyst layer (102), the membrane separator (112), and the outer catalyst layer (122), then forming a lumen (91) around the inner current collector (82) and passing therethrough Such a removable layer (92) is removed so that fluid can pass through. The removable substrate layer (92) preferably comprises a water-soluble polymer such as polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), or polyethylene glycol (PEG).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a microfibrous electrochemical cell, particularly a fuel cell, by using a removable substrate material as an additional coating support to the substrate material. The removable substrate material is then removed to create a lumen in the microfibrous fuel cell that allows the passage of fluid.

2. Description of Related Technology U.S. Pat. No. 5,916,514, U.S. Pat. No. 5,928,808, U.S. Pat. No. 5,989,300, U.S. Pat. Nos. 5,916,514 to Ray R. Eshraghi US Pat. No. 6,004,691, US Pat. No. 6,338,913, US Pat. No. 6,399,232, US Pat. No. 6,403,248, US Pat. 403,517, US Pat. No. 6,444,339, and US Pat. No. 6,495,281. The microfibrous battery structures described in these patents include a hollow fiber structure with which electrochemical cell components are coupled.

  The aforementioned eschergy patent specifically describes a microfibrous fuel cell, which includes an internal current collector, a hollow fiber membrane separator containing an electrolyte medium, an external current collector, and the interior of the membrane separator and It has internal and external electrocatalyst layers on the external surface.

  Such microfibrous fuel cells further include an elongated lumen within the hollow fibrous membrane separator that is a fluid that allows passage of either fuel (eg, hydrogen or methanol) or oxidant (eg, oxygen). Provide a passage. The presence and gaps of such fluid passages are essential for the microfibrous fuel cell to properly perform its proper function of energy generation.

  Conventional methods of manufacturing such microfibrous fuel cells with the required fluid passages are described by “spinning” the film-forming polymer prior to insertion of the internal current collector or simultaneously around the internal current collector. It involves forming a hollow fiber membrane separator by extrusion through an orifice of an extrusion mold called a “die”. Liquid or gas is blown through a perforated tube located in the center of the extrusion orifice so that a lumen is formed in the fibrous membrane separator thus formed. The inner diameter of the hollow fibrous membrane separator is slightly larger than the outer diameter of the internal current collector, thus leaving a fluid passage for the passage of fluid fuel therethrough. More details of such conventional methods are described in US Pat. No. 5,916,514, US Pat. No. 5,928,808, US Pat. No. 5,989,300 and US Pat. No. 004,691.

  However, such conventional methods rely on the use of fluids, liquids or gases, as lumen shaping agents and do not provide sufficient support for deformations caused by external forces during the manufacturing process. Therefore, the hollow fibrous membrane separator formed by such a method is not suitable for a specific section of the membrane separator due to harmful external forces applied to the membrane separator before the membrane separator wall is completely solidified. There may be disadvantages of flat spots pointing to the blockage of the lumens or fluid passages.

  Accordingly, there continues to be a need in the art to provide an easier and faster method for producing microfibrous fuel cells with little or no blockage in the required fluid passages. Yes.

  Further, in the conventional method for producing a microfibrous fuel cell, the internal electrode catalyst layer is formed either at the same time as the hollow fiber membrane separator by coextrusion or after the hollow fiber membrane separator has already been formed. It is formed. Coextrusion processes are very complex and such coextrusion processes provide little or no support for the newly formed internal electrocatalyst and hollow fiber membrane layer prior to complete solidification. For this reason, the internal electrode catalyst and the hollow fiber membrane layer formed by such a process are also subject to considerable deformation. Subsequent catalysis of hollow fiber membrane separators is not only complex, but also increases the risk of plugging the required fluid pathways within such hollow fiber membrane separators during the catalyzing step.

  Accordingly, it is an object of the present invention to provide a production method supported on a substrate of a microfibrous fuel cell, in which an internal electrode catalyst layer can first be formed on a removable substrate, A film-forming material layer is formed on and supported by such an internal electrocatalyst layer, in which case the removable substrate can then be removed to form the required fluid passages in the film-forming material layer. it can. In such a production method supported on a substrate, both the internal electrode catalyst layer and the film-forming material layer are provided with a structural support before their complete solidification. It not only simplifies the overall manufacturing process, but also significantly improves the quality of the microfibrous fuel cells thus formed.

  Other objects and advantages of the invention will become more fully apparent from the ensuing disclosure and appended claims.

SUMMARY OF THE INVENTION One aspect of the invention relates to a method of manufacturing a microfibrous fuel cell structure, comprising at least the following steps:
(A) providing a fibrous substrate structure comprising at least one detachable solid phase substrate material;
(B) coating a layer of film-forming material on the fibrous substrate structure;
(C) then removing such removable substrate material so as to form a hollow fibrous membrane separator having a bore side and a shell side.
In this case, the microfibrous fuel cell structure is
(1) an internal current collector;
(2) an external current collector,
(3) A hollow fibrous membrane separator, the hollow fibrous membrane separator comprising an electrolyte medium and having an internal current collector on the hole side and an external current collector on the body side The hollow fibrous membrane separator further comprising a lumen through which the fluid is allowed to pass,
(4) an internal electrode catalyst layer covering the pore side of the hollow fiber membrane separator;
(5) an external electrode catalyst layer covering the body side of the hollow fiber membrane separator;
Comprising.

  Since the detachable solid phase substrate material of the present invention provides a solid phase substrate having sufficient mechanical strength for the film forming material layer coated thereon, the film forming material layer is still solidified on the film wall. When it is not, it can withstand external forces during the manufacturing process. Such removable solid phase substrate material is then removed to form a lumen through which fluid can pass. Since the detachable solid phase substrate material is removed only after the membrane walls have solidified, such lumens are well protected against deformation during the manufacturing process. Thus, the hollow fibrous membrane separator formed by the method of the present invention includes a net fluid passage with little or no flat spots.

  The term “solid phase” as used herein refers to the state of a material used that is a non-liquid or non-gaseous material at room temperature and atmospheric pressure.

Another aspect of the present application relates to a method of manufacturing a microfibrous fuel cell structure comprising the following steps:
(A) providing an internal current collector in a microfibrous form;
(B) forming at least one layer of removable substrate material on the internal current collector;
(C) forming an internal electrocatalyst layer on at least one layer of such removable substrate material;
(D) forming a film-forming material layer on the internal electrode catalyst layer;
(E) forming an external electrode catalyst layer on the film-forming material layer;
(F) removing at least one layer of such removable substrate material;
(G) A step of attaching an external current collector to the external surface of the external electrode catalyst layer so as to form a microfibrous fuel cell structure.
This microfibrous fuel cell structure is
(1) internal and external current collectors;
(2) internal and external electrode catalyst layers;
(3) a hollow fibrous membrane separator formed by a membrane-forming material layer;
In this case, the hollow fibrous membrane separator has an electrolyte medium and has a hole side and a body side, an internal current collector and an internal electrode catalyst layer on the hole side, and an external side on the body side The hollow fiber membrane separator having a current collector and an external electrode catalyst layer is formed by removing the removable substrate material and has a lumen through which fluid can pass. Further comprising.

  The above method significantly simplifies the manufacturing process of the microfibrous fuel cell, thereby enabling continuous and automated scale-up manufacturing of such a microfibrous fuel cell.

  Such a method is not limited to the production of microfibrous fuel cells. Instead, such a substrate-supported manufacturing method can be widely used in the manufacture of any microfibrous electrochemical cell in which the lumen is required for the passage of fluid therethrough. Such microfibrous electrochemical cells include, but are not limited to, fuel cells, water electrolyzers, chloroalkali cells, and the like.

Thus, yet another aspect of the present invention relates to a method of manufacturing a microfibrous electrochemical cell structure, comprising at least the following steps:
(A) providing a fibrous substrate structure comprising at least one detachable solid phase substrate material;
(B) coating a layer of film-forming material on the fibrous substrate structure;
(C) then removing such removable substrate material so as to form a hollow fibrous membrane separator having a hole side and a body side.
In this case, the microfibrous electrochemical cell structure is
(1) an internal electrode;
(2) an external electrode;
(3) a hollow fibrous membrane separator;
In this case, the hollow fibrous membrane separator comprises an electrolyte medium, and is in electrical contact with the internal electrode on the hole side and the external electrode on the body side, and The pore side of the hollow fibrous membrane separator further comprises a lumen through which fluid can pass.

Yet another aspect of the invention relates to a method of manufacturing a microfibrous fuel cell structure comprising at least the following steps:
(A) providing a core fiber comprising a solid material;
(B) forming at least one layer of a swellable polymer film-forming material on the core fiber;
(C) contacting at least one layer of the swellable polymer film-forming material with a swelling agent so that at least one layer of the swellable polymer film-forming material swells and peels from the core fiber When,
(D) Thereafter, the step of removing the peeled core fibers so as to form a hollow fiber membrane separator having a hole side and a body side.
In this case, the microfibrous fuel cell structure is
(1) an internal current collector;
(2) an external current collector,
(3) A hollow fibrous membrane separator, the hollow fibrous membrane separator comprising an electrolyte medium and having an internal current collector on the hole side and an external current collector on the body side The hollow fibrous membrane separator further comprising a lumen through which the fluid is allowed to pass,
(4) an internal electrode catalyst layer covering the pore side of the hollow fiber membrane separator;
(5) an external electrode catalyst layer covering the body side of the hollow fiber membrane separator;
Comprising.

  The term “swellable polymer film-forming material” as used herein refers to any polymer film-forming material that undergoes volume expansion when contacted with a swelling agent.

  The term “swelling agent” as used herein refers to any liquid or gas that interacts with the polymeric film-forming material and causes such material to undergo volume expansion. Such a swelling agent is preferably water or a liquid solvent such as an organic solvent.

Yet another aspect of the invention relates to a method of manufacturing a microfibrous fuel cell structure, comprising at least the following steps:
(A) providing a core fiber comprising a solid material;
(B) forming an internal electrode catalyst layer on the core fiber;
(C) forming at least one layer of a swellable polymer film-forming material on the internal electrode catalyst layer;
(D) forming an external electrocatalyst layer on at least one layer of such swellable polymeric film-forming material;
(E) contacting the swellable polymer film-forming material layer with a swelling agent to achieve its expansion, from the swellable polymer film-forming material layer and from the inner and outer electrode catalyst layers A step of causing peeling;
(F) The core fiber thus peeled so as to form a hollow fibrous membrane separator having a hole side and a body side, an internal electrode catalyst layer on the hole side, and an external electrode catalyst layer on the body side Step to get rid of.
In this case, the microfibrous fuel cell structure is
(1) an internal current collector;
(2) an external current collector,
(3) A hollow fibrous membrane separator, the hollow fibrous membrane separator comprising an electrolyte medium and having an internal current collector on the hole side and an external current collector on the body side The hollow fibrous membrane separator further comprising a lumen through which the fluid is allowed to pass,
(4) an internal electrode catalyst layer;
(5) an external electrode catalyst layer;
Comprising.

  Other aspects, features, and advantages of the invention will become more fully apparent from the ensuing disclosure and appended claims.

Detailed Description of the Invention and Preferred Embodiments The disclosure of eschergy, namely US Pat. No. 5,916,514, US Pat. No. 5,928,808, US Pat. No. 5,989,300 Specification, US Pat. No. 6,004,691, US Pat. No. 6,338,913, US Pat. No. 6,399,232, US Pat. No. 6,403,248 U.S. Patent No. 6,403,517, U.S. Patent No. 6,444,339, U.S. Patent No. 6,495,281, U.S. Patent Application No. 10 / 188,471, And US patent application Ser. No. 10 / 253,371, each of which is incorporated herein by reference in its entirety for all purposes.

  As used herein, the term “microfibrous” refers to a cross-sectional area ranging from about 10 microns to about 10 millimeters, preferably from about 10 microns to about 5 millimeters, more preferably from about 10 microns to about 1 millimeter. A fibrous structure having an outer diameter.

  The present invention utilizes a detachable solid phase substrate material to form a lumen within a hollow fibrous membrane separator for a microfibrous fuel cell.

  FIG. 10 shows the basic components of a microfibrous fuel cell structure, which includes an internal current collector 82, an internal electrode catalyst layer 102, an electrolyte medium (not shown), an external electrode catalyst layer 122, and an external A hollow fiber membrane separator 112 comprising a current collector 132 is included. The hollow fibrous membrane separator has a hole side and a body side, in which case the hole side includes an internal current collector 82, has an internal electrode catalyst layer 102 coated thereon, and the body side. Is in contact with the external current collector 132 and has an external electrode catalyst layer 122 coated thereon.

  The hollow fibrous membrane separator comprises an electrolyte medium, which can be either a liquid electrolyte medium or a solid electrolyte medium. Such an electrolyte medium is preferably a solid material such as an ion exchange ceramic material or an ion exchange polymer material. The electrolyte medium is selected from the group consisting of perfluorocarbon-sulfonic acid polymers, polysulfone polymers, perfluorocarboxylic acid polymers, styrene-vinyl-benzene-sulfonic acid polymers, and styrene-butadiene polymers. More preferably, it is a solid ion exchange polymer (that is, a cation exchange polymer or an anion exchange polymer). The hollow fibrous membrane separator can be microporous with a liquid or solid electrolyte medium impregnated in the micropores of the membrane separator. More preferably, the hollow fibrous membrane separator itself is a solid ion exchange membrane, which consists essentially of either a solid ion exchange ceramic or a solid ion exchange polymer and has structural support. It serves both as a membrane matrix that provides the body and as an electrolyte medium for performing electrochemical reactions. Examples of such ion exchange polymer membranes include Nafion® membranes manufactured by DuPont (Fayetteville, NC), manufactured by Asahi Glass Co., Tokyo, Japan. By Flemion® membranes, Aciplex® membranes manufactured by Asahi Kasei Corporation (Osaka, Japan), and Dow Chemical (Midland, Michigan) The manufactured Dow XUS membrane is included.

  The pore side of the hollow fibrous membrane separator further includes a lumen 91 that allows passage of fluid fuel (eg, hydrogen and methanol) or oxidant (eg, oxygen) therethrough. Such a lumen 91 provides a fluid passage that is essential for the microfibrous fuel cell and performs its energy generation function, and the blockage of the lumen 91 may adversely affect the output performance of the fuel cell.

  Thus, the present invention initially occupies the space designed for such a lumen 91 using a removable solid phase substrate material, while during various manufacturing steps such as coating / drying / curing, etc. A film-forming material layer is formed on and supported by the top surface of such removable solid substrate material. After the membrane-forming material layer is sufficiently solidified, this solid phase substrate material is then selectively removed to form a hollow space or lumen 91 in the hollow fibrous membrane separator 112.

  The detachable solid phase substrate material of the present invention provides a solid core with high mechanical strength, which forms various components of a microfibrous fuel cell structure as described above. Supports subsequent coatings of additional layers of various materials, and it then preserves space for forming net fluid passages in such microfibrous fuel cell structures. The removable substrate material also provides additional cushioning for the film-forming material layer against potential breakage due to deflection or twisting during the manufacturing process.

  The removable substrate material of the present invention is subject to subsequent removal by a selective method, i.e., without removing the basic components or parts of the microfibrous fuel cell structure. For example, any appropriate material that is a solid phase at room temperature and atmospheric pressure, such as metal, glass, ceramic, and polymer, can be used. For example, such a removable substrate material can be a sublimable material, which can be a microfibrous fuel cell, such as internal and external current collectors, internal and external electrode catalyst layers, and hollow fibrous membrane separators. Sublimable under sublimation conditions that do not affect the basic components of the structure, and also meltable under melting conditions that do not affect the basic components of the microfibrous fuel cell structure The material can be a soluble material that can be dissolved by a solvent that does not affect the basic components of the microfibrous fuel cell structure.

  In a preferred embodiment of the present invention, such removable substrate materials are soluble materials such as acid soluble materials, alkali soluble materials, organic solvent-solvent materials and water soluble materials.

  In a more preferred embodiment of the present invention, such removable substrate material is a water soluble polymeric material. Since water is the remover that has the least penetration with respect to the basic components of the microfibrous fuel cell structure, it is particularly suitable to practice the present invention to use a water-soluble polymeric material. Furthermore, the use of water as a removal agent is economical and environmentally friendly.

  The water-soluble polymer used to practice the present invention can be any suitable natural or synthetic polymer material that is water-soluble and can coexist with materials that are subsequently coated onto the substrate structure. Examples of such water-soluble polymers include polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, acrylic acid-type water-soluble polymers, maleic anhydride-type water-soluble polymers, poly (N-vinylamide), polyacrylamide, polyacrylamide (Ethyleneimine), poly (hydroxy-ethyl methacrylate), polyester, poly (ethyloxazoline), poly (oxymethylene), poly (vinyl methyl ether), poly (styrene sulfonic acid), poly (ethylene sulfonic acid), poly (Vinyl phosphorus) acid, poly (maleic acid), starch, cellulose, protein, polysaccharide, dextran, tannin, lignin and the like are included.

  Such list of water soluble polymers is exemplary only and is not intended to limit the broad scope of the invention. Such a water-soluble polymer is preferably selected from polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol and mixtures thereof. More preferably, the water-soluble polymer comprises polyvinyl pyrrolidone and / or polyvinyl alcohol.

  FIG. 1 shows a fibrous substrate structure 10 consisting essentially of a water-soluble substrate material 12. The fibrous substrate structure 10 is then coated with a layer of film-forming material 22 so as to form a coated fiber 20. After the film-forming material 22 is solidified, the water-soluble substrate material 12 is removed by immersing the coated fibers 20 in warm water or by flowing warm water through the coated fibers 20 and the lumens therein. Only the body of the membrane forming material 22 having 31 is left, and the hollow fiber membrane separator 30 is obtained.

  At the same time or in sequence, the internal and external current collectors can then be attached to the hollow fiber membrane separator 30 in an appropriate sequence or combination, and the internal and external electrode catalyst layers are then attached to the hollow fiber membrane separator 30. Can be applied. For example, the internal and external current collectors can be simultaneously attached to the hollow fiber membrane separator, followed by application of the internal electrode catalyst layer and then application of the external electrode catalyst layer. Alternatively, the inner and outer electrode catalyst layers can be applied simultaneously to the hollow fiber membrane separator, followed by attachment of the inner and outer current collectors. One of ordinary skill in the art can easily design and negotiate an appropriate protocol for manufacturing such a microfibrous fuel cell, depending on the specific materials and system conditions.

  Various methods of applying internal and / or external electrocatalyst layers to form a finished microfibrous fuel cell structure as described above are described in US patent application Ser. No. 10/253, filed Sep. 24, 2002. No. 371, “Microcell Fuel Cell, Fuel Cell Assembly, and Method for Producing the Same (MICROCELL FUEL CELLS, FUEL CELL ASSEMBLIES, AND METHODS OF MAKING THE SAME)”, the contents of which are incorporated herein by reference. The entirety of which is incorporated herein for all purposes.

  Subsequent removal of the removable solid substrate material is preferably, but not necessarily, facilitated by providing a removal interface that contacts at least a portion of the removable substrate material. Such removal interface increases the active processing surface of the removal agent such as acid, alkali, organic solvent or water, and thus facilitates removal of the substrate material. Such removal interface is preferably an open cavity in the removable substrate material through which removal fluid can pass to remove the substrate material.

  FIG. 2A shows a cross-sectional view of a coated fiber having a fibrous substrate structure covered by a layer of film-forming material 22 ′, where such fibrous substrate structure is removable substrate material 12. It comprises an open cavity 21 inside. Open cavity 21 is elongated and provides a passage for removal fluid to facilitate removal of substrate material 12 '. The open cavity may be in the middle of the removable substrate 12 'as shown in FIG. 2A or near the outer surface of the removable substrate 12' as shown in FIG. 2B.

  The removal interface described above may be formed from the beginning or later. Specifically, such a removal interface can be formed by using two or more kinds of detachable substrate materials having different peelability. FIG. 3 shows a process for forming a hollow fibrous membrane separator using a fibrous substrate comprising two removable substrate materials 12 'and 14' having different peel properties. A first detachable substrate material 14 (which can be either a solid phase material or a non-solid phase material) is coated with a second detachable solid phase substrate material 12 ′ to provide a first detachable material. The substrate material 14 is more easily detachable than the second detachable solid phase substrate material 12 '. A layer of film-forming material 22 'is coated over and solidified therewith on the second removable solid phase substrate material 12'. After solidification of the layer 22 ′, the first removable substrate material 14 is first removed, leaving an open cavity 21 in the second removable solid phase substrate material 12 ′ through which the removal fluid passes. Thus, the second detachable solid phase substrate material can be removed.

  For example, such a first detachable substrate material 14 can comprise a low molecular weight, water soluble polymeric material, and a second detachable solid phase substrate 12 ′ can be a high molecular weight, water soluble polymer. It can comprise a polymeric material. Alternatively, the first detachable substrate material 14 can comprise a water-soluble polymeric material, and the second detachable solid phase substrate 12 ′ is a water-insoluble and acid-soluble glass material. Can comprise. Various combinations of materials can be used to construct a fibrous substrate from two removable substrate materials that differ in peelability. Such fibrous substrates also have more than two types of desorption with different release properties, as long as a removable solid phase substrate material is provided in the outermost layer and provides a structural support for the coating that is subsequently applied thereto. Possible substrate materials can be included.

  It is important to note that the hollow microfibrous membrane separator of the present invention can also be advantageously formed by using a swellable polymeric membrane-forming material, which includes a volume when contacted with a swelling agent. An appropriate polymer film forming material that causes expansion is included. Suitable examples of swellable polymer film-forming materials include ion exchange polymers such as Nafion and perfluorosulfonic acid polymers. The swelling agent used for realizing the volume expansion of such a polymer film forming material is not necessarily a liquid solvent such as water or an organic solvent.

  Such swellable polymeric film forming materials can be coated directly on solid core fibers such as metal wires or carbon wires, dried and cured to form a solidified polymeric film, which is And then contact with the swelling agent to cause expansion and thereby peel from the solid core fiber. Pulling out or otherwise, by removing the peeled solid core fibers, a hollow microfibrous polymer membrane is formed, using such hollow microfibrous membrane to perform subsequent processing steps, A completed microfibrous fuel cell can be formed.

  In another embodiment, the inner electrocatalyst layer, the swellable polymer film forming layer, and the outer electrocatalyst layer can be sequentially formed on the solid core fiber. A swelling agent is then contacted with these layers to achieve expansion of the swellable polymer film-forming layer, thereby in turn solids from the polymer film-forming layer and the inner and outer electrocatalyst layers. Detachment of the core fiber is caused. After the stripped core fiber is removed, a hollow microfibrous membrane separator is formed, which defines a cylinder side and a hole side, an internal electrode catalyst layer on the hole side, and an external on the cylinder side It has an electrode catalyst layer.

  An internal current collector having a diameter smaller than the diameter of the removed solid core fiber is inserted into the hole of the hollow microfibrous membrane separator, and the external current collector is placed on the trunk side of the membrane separator, A completed microfibrous fuel cell can be formed.

  Another embodiment of the present invention includes forming a hollow fiber membrane separator having an internal current collector therein from the beginning, whereby the internal current collector is later placed in the membrane separator. The insertion step is avoided and the overall manufacturing process is simplified.

  Specifically, as shown in FIG. 4, first, a conductive fiber 40 that can function as an internal current collector is provided. Such conductive fibers 40 comprise a conductive material 42, which can be a metal, metal alloy, carbon, conductive polymer, or the like. The conductive fibers 40 are coated with a layer of removable substrate material 52 to form a fibrous substrate structure 50, which is then coated with a layer of film-forming material 62. After the membrane-forming material 62 is solidified, the coated fiber 60 is treated to remove the removable substrate material 52 to form a hollow fibrous membrane separator 70 having a lumen 71 and an internal current collector 40 therein. Is done.

  In order to form a completed microfibrous fuel cell structure as described above, an external current collector can be attached to the hollow fiber membrane separator 70 at the same time or sequentially in an appropriate order or in an appropriate combination. Can be coated with internal and external electrode catalyst layers.

  A removal interface as described above could also be provided adjacent to the internal current collector to facilitate removal of the removable substrate material. For example, FIG. 5 shows a coated fiber having a film-forming material layer 62 ′ coated on a detachable solid phase substrate material 52 ′ with the detachable solid phase substrate material therein It includes an internal current collector 42 ′ and a removal interface 51. Such removal interface 51 is preferably an open cavity through which removal fluid passes to effectively remove substrate material 52 '.

  FIG. 6 shows a fiber coated in accordance with another embodiment of the present invention, which has a film-forming material layer 62 ′ coated over the fibrous substrate structure, the fibrous substrate structure comprising Out of the internal current collector 42 ', a first detachable substrate material 54' (which can be either solid or non-solid), and a second detachable solid substrate material 52 '. Comprising. The first removable substrate material 54 ′ is more easily removable compared to the second removable solid phase substrate material 52 ′ and is therefore removed first to form the removal interface 51. The Next, removal of the second detachable solid phase substrate material 52 ′ is performed at the removal interface 51, and a lumen 71 is formed in the film forming material layer 62 ′. In addition to the examples provided herein, the fibrous substrate structure can comprise an additional layer of a removable substrate material with different peelability, as long as the outermost layer comprises a solid phase substrate material.

  FIG. 7 shows a fiber coated according to yet another embodiment of the present invention, which has a film-forming material layer 62 ′ coated on the fibrous substrate structure, the fibrous substrate structure comprising: It comprises an internal current collector 42 ′ placed side by side with the soluble fiber 56 and encapsulated by a removable solid substrate material 52 ′. First, the soluble fibers 56 are removed to provide a removal interface 51, and then the removable solid substrate material 52 'is removed to form the lumen 71. Formation of the removal interface 51 significantly increases the removal rate of the removable solid phase substrate material 52 'and is therefore preferred in the present invention.

  As described below, in addition to the internal current collector, a removable substrate material is used to form additional components of the microfibrous fuel cell structure from the beginning into the hollow fibrous membrane separator. be able to.

  FIG. 8 shows a process for forming a hollow fibrous membrane separator having an internal current collector and an internal electrode catalyst layer formed therein from the beginning. First, a coated fiber structure is provided, which comprises a fibrous substrate structure and a film-forming material layer 112 coated on the fibrous substrate structure. This fibrous substrate structure includes an internal current collector 82, a detachable substrate material layer 92, and an internal electrode catalyst layer 102 from the inside to the outside. After removing the detachable substrate material layer 92, the membrane forming material layer 112 forms a hollow fibrous membrane separator, which has an internal current collector 82, a lumen 91 and such a hollow fibrous membrane separator on the hole side. The inner electrode catalyst layer 102 is coated on the inner surface of the inner electrode.

  FIG. 9 shows the process of forming a hollow fiber membrane separator having an internal current collector formed therein from the beginning and internal and external electrocatalyst layers. Specifically, a multi-layer structure is provided that includes, from inside to outside, an internal current collector 82, a detachable substrate material layer 92, an internal electrode catalyst layer 102, a film forming material layer 112, and external electrodes. The catalyst layer 122 is included. After removing the detachable substrate material layer 92, the membrane-forming material layer 112 forms a hollow fibrous membrane separator, which includes an internal current collector 82, a lumen 91, and an internal electrode catalyst layer 102 on the hole side. Including an external electrode catalyst layer 122 on the cylinder side. Thereafter, an external current collector can be attached to the hollow fibrous membrane separator to form a completed microfibrous fuel cell structure as described above.

  The microfibrous fuel cell structure can be manufactured in a series of coating / processing / removal steps by using the detachable solid phase substrate material of the present invention, which is a microfibrous fuel cell scale. It can be achieved in a continuous automated manner for up-commercial production.

In a specific embodiment of the invention, the microfibrous fuel cell structure can be formed by a series of sequential steps including:
(A) providing an internal current collector for microfibrous confirmation;
(B) forming at least one layer of removable substrate material on the internal current collector;
(C) forming an internal electrocatalyst layer on at least one layer of the removable substrate material;
(D) forming a film-forming material layer on the internal electrode catalyst layer;
(E) forming an external electrode catalyst layer on the film-forming material layer;
(F) removing at least one layer of the removable substrate material;
(G) A step of attaching an external current collector to the external surface of the external electrode catalyst layer.

  In the following sections, each of the steps listed above for producing such a microfibrous fuel cell structure is described in detail.

Formation of Removable Substrate Material Layer At least one layer of removable substrate material is formed on a microfibrous internal current collector, the microfibrous internal current collector comprising metal, metal alloy, carbon and conductive The conductive fiber can be any suitable material such as a conductive polymer.

  Such removable substrate material layers can be formed using any suitable method, including but not limited to melt extrusion, solution extrusion, ink extrusion, spray coating, brush coating, dip coating and vapor deposition. Can be formed.

A preferred method of forming a removable substrate material layer on an internal current collector is melt extrusion, which includes the following steps:
(I) providing a removable substrate material as a melt;
(Ii) extruding the molten removable substrate material onto an internal current collector to form a layer of a desired thickness;
(Iii) cooling the formed layer for a sufficient amount of time to form a solidified layer of removable substrate material.
These steps can be repeated multiple times to form multiple layers of the same or different removable substrate material.

  Melt extrusion is advantageous because the formed layer of detachable substrate material can be easily and quickly solidified by cooling, and cooling can be performed in the air, or in a substrate material or internal current collector from which a liquid bath is detachable. This is done either in a liquid bath provided that it contains a liquid that does not attack or remove the device so much. When the removable substrate material comprises a water soluble polymer such as polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and polyethylene glycol (PEG), most water soluble polymers are from about 40 ° C. to about 100 ° C. Such liquid baths may contain cold water because it is slightly soluble in water at high temperatures in the range of 0 C, but little or no solubility in cold water at lower temperatures.

Another suitable method for forming a removable substrate material layer on an internal current collector is solution extrusion, which includes the following steps:
(I) providing a viscous solution of the removable substrate material;
(Ii) extruding a viscous solution over an internal current to form a layer of the desired thickness;
(Iii) treating the formed layer of the viscous solution for a sufficient time to form a solidified layer of removable substrate material.

  The viscous solution of the removable substrate material can be formed by using an appropriate appropriate solvent. For example, if the desorbable substrate material is a water soluble polymeric material (ie PVP, PVA or PEG), such a viscous solution can be formed using only water as a solvent and is desorbable. If the substrate material is a polymeric material that is not soluble in water but soluble in organic solvents, such a viscous solution can now be formed by using a suitable organic solvent. In the present invention, a co-solvent or a multi-solvent system can be easily used depending on the specific type of detachable substrate material used.

  The viscosity of such viscous solutions should be controlled within an appropriate range, for example, about 100 poise to about 2000 poise as measured with a rotational viscometer using a Brookfield rotary spindle viscometer. A solution that is too thick will not be evenly spread over the surface of the internal current collector, and a solution that is too thin will not provide a sufficiently thick layer. Therefore, by controlling the viscosity of the detachable substrate material solution, a layer having a desired thickness can be uniformly applied on the internal current collector.

  Solidification of the viscous solution of the removable substrate material can be accomplished by air drying, heat drying, or so as to drive off the solvent from the viscous solution and to solidify the layer of removable substrate material. This can be done either by passing through a coagulation bath.

  The viscous solution of the removable substrate material is preferably provided at an elevated temperature during the extrusion step, so that the removable substrate material is immediately removed from the solution when the viscous solution exits the extrusion die. Appear, and because of the rapid drop in temperature, a semi-solid that will require minimal heating to eliminate residual solvent will be obtained. Such a process is usually referred to as a thermally induced phase separation process.

  Also, in the case of a removable substrate material that does not easily form a solution (eg, polytetrafluoroethylene), ink extrusion is used to provide a paste of such removable substrate material, overlying the internal current collector. By extruding the paste, a detachable substrate material layer can be formed on the internal current collector.

  In the present invention, the extrusion step comprises, as shown in FIG. 11, fibers or coated fibers, a melted material (in the case of melt extrusion), a viscous solution (in the case of solution extrusion), or an ink Pull through an application die filled with paste (in the case of ink extrusion) and over these fibers an additional layer of material (eg a layer of removable substrate material in this section, or an electrode in the next section) It is preferably carried out by applying a layer of catalyst material). Such an extrusion technique is a combination of wire coating and pultrusion and can be used throughout the application for the purpose of extruding an additional layer of material over thin fibers.

Formation of Internal Electrocatalyst Layer The internal and external electrode catalyst layers can be formed from the beginning into hollow fiber membrane separators or US patent application Ser. No. 10 / 253,371 filed Sep. 24, 2002, “ It can be formed by subsequent catalysis of the hollow fiber membrane separator in accordance with various catalysis methods disclosed in "Microcell Fuel Cells, Fuel Cell Assemblies, and Methods for Producing the Same". This patent application is incorporated herein by reference.

  The internal electrode catalyst layer can be formed from the beginning by various methods including, but not limited to, ink extrusion, spray coating, brush coating, dip coating, chemical deposition, electrochemical deposition and vapor deposition. .

In the present invention, when the internal electrode catalyst layer is formed from the beginning on the detachable substrate material layer, ink extrusion is a preferred method. Such an ink extrusion method can include the following steps:
(I) providing an ink paste comprising an electrocatalytic material;
(Ii) extruding an ink paste over the removable substrate material layer to form a layer of a desired thickness;
(Iii) treating the ink paste for a sufficient time to form a solidified electrocatalyst layer;

  The electrocatalyst material can comprise a metal selected from the group consisting of platinum, gold, ruthenium, iridium, palladium, rhodium, nickel, iron, molybdenum, tungsten, niobium, and alloys thereof. Such an electrocatalyst material comprises platinum or a platinum alloy such as platinum-ruthenium alloy, platinum-ruthenium-iron alloy, platinum-molybdenum alloy, platinum-chromium alloy, platinum-tin alloy and platinum-nickel alloy. Is preferred.

  The ink paste used in the present invention can comprise at least a conductive material (eg, carbon powder or metal powder), an electrolyte, an electrocatalyst, and any other suitable performance improving additive. Specifically, such an ink paste contains, in addition to the electrode catalyst, carbon powder, the same ion exchange polymer electrolyte material contained in the hollow fiber membrane separator, a polymer binder, and a solvent. Can be. The electrocatalyst material in such ink paste is from about 5% to about 90%, preferably from about 20% to about 60%, based on the total weight of the ink paste. Can vary up to. Specifically, catalyst slurries commercialized by Johnson Matthey, Inc. (Taylor, Mich.) Can be used for the purposes of practicing the present invention, It comprises 20 w /% platinum-carbon powder and 5 w /% Nafion® binding material in a glycerol solution.

  This ink paste can be treated either by heat drying or by contacting the ink paste with a coagulant to form a solidified internal electrode catalyst layer.

Formation of Film Forming Material Layer The film forming material layer includes, but is not limited to, methods for forming a removable substrate material layer, including melt extrusion, solution extrusion, spray coating, brush coating, dip coating and vapor deposition. Can be formed on the internal electrode catalyst layer by substantially the same method.

A preferred method of forming such a film-forming material layer is by solution extrusion and includes the following steps:
(I) providing a viscous solution of the film-forming material;
(Ii) extruding a viscous solution over the internal electrocatalyst layer to form a layer of a desired thickness;
(Iii) treating the viscous solution layer for a sufficient amount of time to form a solidified film-forming material layer;

  The viscous solution can comprise from about 10% to about 50% of such film-forming material, based on the total weight of the solution. Depending on the specific type of film-forming material used, various solvents or solvent systems can be used to form such a solution. For example, such film-forming materials are perfluorosulfonates such as Nafion (registered trademark) (DuPont), Flemion (registered trademark) (Asahi Glass), Aciplex (registered trademark) (Asahi Kasei) and Dow XUS (Dow Chemical). When comprising an ionomer film material, a water-alcohol cosolvent system can be used to form a viscous solution of such film forming material. Specifically, a coated fiber comprising an internal current collector, a detachable substrate material layer, and an internal electrocatalyst layer to extrude a layer of Nafion® solution over the coated fiber Can be drawn through an applicator die filled with 20-30 w /% Nafion (R) solution to form a Nafion (R) layer.

  The film-forming material layer can then be solidified by heat drying or by contacting such a layer with a coagulant to enhance the solidification of the film-forming material layer. Such a film-forming material is preferably first cured at a high temperature that is at least the glass transition temperature (Tg) of the film-forming material, and then cooled to form a solidified layer. The material is cured preferably at a temperature in the range of about 100 ° C to about 250 ° C, most preferably in the range of about 110 ° C to about 150 ° C. The curing temperature can be easily modified depending on the specific requirements of the film layer to be formed. Usually, the higher the curing temperature, the lower the water content of the membrane layer and the stronger the membrane layer, but the membrane layer thus formed is less ionic and therefore less conductive. It becomes exchange condition.

  The hollow fibrous membrane formed by this step can be a solid membrane consisting essentially of a solid electrolyte material, such as an ion conductive ceramic or polymer. Alternatively, this type of hollow fibrous membrane formed in this way is microporous and can have a solid electrolyte material impregnated in the micropores. In particular, such hollow fibrous membranes can be microfiltration membranes, ultrafiltration membranes or reverse osmosis membranes, as described in US Pat. No. 5,916,514 to Escherry.

Formation of the external electrode catalyst layer The external electrode catalyst layer is formed by substantially the same method as that for forming the internal electrode catalyst layer, provided that the external electrode catalyst layer is formed on the upper surface of the film forming material layer. On the other hand, the internal electrode catalyst layer is excluded from being formed on the upper surface of the substrate material layer to be removed. In order to enhance the structural integrity of the multilayer fiber structure thus formed, it is preferable to apply a soluble protective coating on the external electrode catalyst layer.

Removal of Substrate Material Removal of substrate material depends on the specific removable substrate material used. For example, if the desorbable substrate material is a sublimable material, the removal includes sublimation, and if the demountable substrate material is a meltable material, the removal includes melting and desorption. If the possible substrate material is a soluble material, removal would include the use of a solvent such as an acid, alkali, organic solvent, or water. If the detachable substrate material comprises a water soluble polymer, the removal is performed by immersing the multilayer fibrous structure in water for a sufficient time so as to remove a substantial portion of the detachable substrate material. Or it is preferable to carry out by flowing water through the hole of this multilayer fiber structure. More preferably, the water is heated to a high temperature in the range of about 40 ° C. to about 100 ° C. to increase the removal rate of the substrate material.

  It should be noted that complete removal of the removable substrate material is desired, but the present invention does not require this during the manufacture of microfibrous fuel cells. Individual microfibrous fuel cells are formed, and when bundled / sealed into multiple microfibrous fuel cells, only a portion of the substrate material is removed to form a module having a hole side and a barrel side, and then such Water can be flowed through the pore side of the microfibrous fuel cell module to remove the remaining substrate material from the pores of a number of microfibrous fuel cells of the module.

  Various configurations of the detachable substrate structure described above comprising either a removal interface in contact with the substrate material or two or more detachable substrate materials having different peelability facilitates removal of the substrate material. And those skilled in the art can readily select an appropriate configuration adapted to specific system requirements consistent with the disclosure herein.

  The following are examples of various ink coatings applied over a fibrous structure to form an internal or external electrode catalyst layer.

  In another embodiment of the present invention, the ink paste applied to the pore side and / or the cylinder side of the hollow fiber membrane separator may or may not contain an electrode catalyst. For example, such ink pastes do not include a platinum catalyst, but may include only carbon or other conductive materials such as, for example, niobium, titanium, titanium carbide, titanium nitride, niobium carbide, niobium nitride. Catalysis of the microfibrous fuel cell can be achieved after removal of the removable substrate material, or even after that, ie after assembling a large number of microfibrous fuel cells into a bundle, which was filed on September 24, 2002 in the United States. This can be carried out according to the catalyzing method disclosed in Japanese Patent Application No. 10 / 253,371, “Microcell Fuel Cell, Fuel Cell Assembly, and Manufacturing Method Thereof”.

  Yet another example relating to the manufacture of a microfibrous fuel cell structure according to a preferred embodiment of the present invention is provided below.

Example 1
In the manufacture of the microfibrous fuel cell of this example, a 304 grade stainless steel wire having a diameter of 0.020 "was prepared as an internal current collector.

  Polyvinylpyrrolidone (PVP) solution (Luvitec K60, 45% by weight, supplied by BASF Corporation) is extruded onto an internal current collector and subsequently dried to provide a removable polymer A layer was formed on such an internal current collector.

  The extrusion process conditions for PVP60 were as follows:

  After drying, the fibers were collected in a reel. The fiber cross-section was examined under a microscope and measured with a micrometer, and the fiber was shown to have a PVP layer of about 50-60 microns and an outer diameter of about 600-617 microns.

  Subsequently, a 1100 EW Nafion polymer solution (DuPont DE-2021) was extruded onto the PVP60 coated fiber to form a membrane layer on the PVP60 coated fiber.

  Specifically, a concentrated solution of 31.5 wt% Nafion was prepared by concentrating diluted 20 wt% Nafion (DuPont DE-2021). A first layer of concentrated 31.5 wt% Nafion solution was extruded onto a PVP coated current collector. The extrusion process conditions for 31.5 wt% Nafion were as follows:

  In order to ensure the formation of a continuous film without leakage, a second layer of concentrated 32 wt% Nafion solution was added to the first of 31.5 wt% Nafion solution under the following extrusion process conditions: Extruded onto the layer:

  The Nafion coated fiber was cut to the desired length, dried at 70 ° C. for 30 minutes, and then heat set at 125 ° C. for 1 hour. The cured fiber is then placed in warm water for several hours to form a lumen for passing liquid or gaseous fuel or oxidant in the hollow microfibrous Nafion membrane layer and the internal current collector is removed. Without dissolving, the PVP60 layer was dissolved and removed.

  The hollow microfibrous Nafion membrane / internal current collector assembly thus formed has an inner diameter and outer diameter of about 570 and 760 microns, respectively, while the Nafion membrane layer thickness is about 85-95. It was micron.

  Then, using the hollow microfibrous Nafion membrane / internal current collector assembly described above according to the catalysis technique disclosed in US patent application Ser. No. 10 / 253,371, the pore side of the Nafion membrane layer is used. And the cylinder side was catalyzed with platinum, and then the finished microfibrous fuel cell could be manufactured by placing an external current collector of 380 microns on the cylinder side of the catalyzed membrane.

The equipment used to manufacture the microfibrous fuel cell includes:
Wire reel delivery stand Single layer extrusion die for applying Nafion to the wire Piston pump Medium wave infrared dryer-1 meter long Pull-out device with belt to move the wire through the process Winding the final product together into a reel apparatus

Example 2
A hollow microfibrous Nafion membrane / internal current collector assembly was manufactured by substantially the same process as described in Example 1. However, the removable substrate is a first removable layer of PVP 60 as described above in Example 1 and a second removable layer of polyvinyl alcohol PVA (DuPont's Elvanol, grade 70-62). Except that it consisted of two detachable polymer layers including a layer.

  An aqueous solution of PVA was prepared by gradually dissolving the PVA polymer in warm water while stirring. The PVA concentration of the solution was 13% by weight, which was sufficient for the extrusion process. A second infrared device was placed in the line to ensure complete drying of the PVA layer. The process conditions for PVA extrusion were as follows:

  The thickness of the extruded PVA layer was about 10 microns.

  As in Example 1, two layers of concentrated Nafion solution were extruded onto PVP / PVA coated fibers, which were then cut to the desired length and heat treated. First, in order to provide a removal interface, the PVP60 layer was removed using slightly warm water and the removal of the PVA layer was further facilitated by using warm water to hot water.

  The hollow microfibrous Nafion membrane / internal current collector assembly thus formed had inner and outer diameters of 565 and 780 microns, respectively. An external current collector is deposited on the barrel side of the catalyzed Nafion membrane by depositing internal and external electrode catalyst layers on the internal and external surfaces of the hollow microfibrous Nafion membrane and as described in Example 1. A finished microfibrous fuel cell was formed by placing the device.

Example 3
A microfibrous fuel cell was prepared as follows.

  First, a detachable layer of polyvinylpyrrolidone (PVP) was formed by extruding a 45% rubitec K60 PVP solution (supplied by BASF) around a titanium wire. Next, an internal electrode catalyst layer was applied onto the PVP coated wire by ink extrusion. Two film-forming layers of concentrated 32 wt% Nafion solution were sequentially extruded onto the internal electrocatalyst layer.

  Specifically, a 32 wt% concentrated Nafion was obtained by concentrating a diluted Nafion solution containing 20 wt% Nafion 1100EW (from Solution Technology) in a mixture of alcohol and water. The concentrated Nafion solution had a viscosity of 890 poise as measured by a rotational viscometer equipped with a # 4 spindle (Brookfield LVT model) at 6 rpm.

  The catalyst ink used to form the internal electrode catalyst layer was prepared by mixing:

  3% polyacrylic acid was 4 million Mw (weighted by average molecular weight) dissolved in 5% alcoholic Nafion. The viscosity of the catalyst ink was about 9 poise as measured by a Brookfield LVT rotational viscometer equipped with a # 4 spindle at 60 rpm.

  The process conditions for the extrusion process are outlined in Table III below. Each of the extrusion steps was performed at an ambient temperature of about 72 ° F. (22 ° C.), and drying was performed using a 1 meter long medium wave infrared device.

  The outer diameter of the multilayer assembly thus formed was about 800-810 microns.

  The multilayer assembly was then cut to the desired length. The external electrode catalyst layer was formed on the Nafion membrane layer ink by brushing the catalyst ink paste thereon. Specifically, a catalyst ink for forming the external electrode catalyst layer was prepared by mixing the following materials.

  The catalyst ink paste was dried in an air circulating oven at 70 ° C. for 30 minutes and then at 125 ° C. for 1 hour.

  The titanium wire (i.e., the internal current collector) therein is then released to release the Nafion membrane layer and to form a lumen in the Nafion membrane layer for the passage of liquid or gaseous fuel or oxidant. Without removing the device, the multilayer fiber was placed in water for a sufficient amount of time to dissolve and remove the PVP layer.

  The final completed microfibrous fuel cell was formed by placing an external current collector on the barrel side of the released and catalyzed Nafion membrane / internal current collector fibrous assembly.

Example 4
In this example, the microfibrous fuel cell was formed by substantially the same steps as described in Example 3. However, an external electrode catalyst layer was used to protect the layer when a different catalyst ink was used to form the external electrode catalyst layer, and when the fibrous assembly was passed through a drawing device and a winding device. Except that an additional thin protective layer of PVP (Rubitec K60) was applied on top.

  Specifically, the catalyzed ink used to form the external electrode catalyst layer was prepared by mixing the following materials.

  The viscosity of the catalyzed ink was about 9 poise as measured by a Brookfield LVT rotational viscometer equipped with a # 4 spindle at 60 rpm.

  The protective PVP layer was formed by extruding a 40 wt% PVP aqueous PVP solution onto the outer electrocatalyst layer.

  The process conditions for extruding the external electrode catalyst layer and the protective PVP layer were as follows:

  The protective PVP layer is removed during a subsequent post-extrusion step, in which case the removable PVP substrate is selectively removed (as described in Example 3) and within the hollow microfibrous Nafion membrane. A lumen for the passage of hydrogen fuel or air was formed.

Example 5
A 0.020 "diameter 304 grade stainless steel wire was provided and a 1100 EW Nafion polymer solution (supplied by Solution Technology) was used to form a swellable Nafion membrane layer thereon.

  Specifically, a concentrated 32 wt% Nafion solution was obtained by concentrating a diluted Nafion solution containing 20 wt% Nafion 1100EW in a mixture of alcohol and water. The concentrated 32 wt% Nafion solution had a viscosity of 890 poise as measured by a rotational viscometer equipped with a # 4 spindle (Brookfield LVT model) at 6 rpm.

  The 32 wt% Nafion solution was extruded onto stainless steel wire in a continuous automated manner using a piston-type pump. The Nafion-coated wire was then passed through a medium wave infrared dryer to dry and cure the Nafion membrane layer.

  The extrusion process conditions were as follows:

  After drying, the resulting Nafion membrane layer thickness was about 40-50 microns. Next, the Nafion-coated fiber was passed through a belt-drawing device to a winding device that winds the fiber around a winding frame.

  The Nafion coated fiber was then cut to the desired length, dried at 70 ° C. for 30 minutes, and then heat set at 125 ° C. for 1 hour. The Nafion coated fiber was then placed in water for a sufficient amount of time so that the Nafion membrane layer swelled and thereby allowed to peel from the stainless steel wire. The 0.020 "stainless steel wire was removed to form hollow microfibrous Nafion membranes having inner and outer diameters of 520 and 600 microns, respectively.

  The hollow microfibrous Nafion membrane is then used to catalyze the pore and barrel sides of the membrane with a platinum catalyst according to the catalysis technique disclosed in US patent application Ser. No. 10 / 253,371. And by placing a current collector of 380 microns on the hole side and the trunk side of the catalyzed Nafion membrane, a completed microfibrous fuel cell could be produced.

The equipment used to manufacture the microfibrous fuel cell includes:
Wire reel delivery stand Single layer extrusion die for applying Nafion to the wire Piston pump Medium wave infrared dryer-1 meter long Pull-out device with belt to move the wire through the process Winding the final product together into a reel apparatus

Example 6
In the manufacture of the microfibrous fuel cell of this example, the materials used included:
0.020 "diameter titanium wire Catalytic ink paste to form internal electrode catalyst layer 20 wt% Nafion (DuPont DE-2021) solution Concentrated 32 wt% Nafion solution Form external electrode catalyst layer Catalyst ink paste for

The equipment used to manufacture the microfibrous fuel cell includes the following:
Delivery stand for wire reel Single layer extrusion die for extruding catalyst ink paste Piston pump Infrared dryer Coated die for applying thin layer of 20 wt% Nafion solution on ink Hot air drying chamber Concentration Second Extrusion Coated Die for Applying 32% by Weight Nafion Solution Second Infrared Drying Oven Belted Drawer to Move Wire Through Process Winder to Bundle Final Product into Reel

A catalyst ink paste for forming the internal electrode catalyst layer was prepared by mixing the following:
Platinum black (HiSpec 1000 from Alpha Eisal) is 20.5% by weight
5% aqueous Nafion solution (from Solution Technology) 73%
5% solution of polyethylene oxide in deionized water (600,000 Mw PEO, supplied by Aldrich Chemical)
1.5% pure Triton surfactant (Triton X-100, from Aldrich Chemical)

  The viscosity of the ink paste was 22 poise as measured by a Brookfield LVT rotational viscometer equipped with a # 4 spindle at 60 rpm.

  A concentrated 32 wt% Nafion solution was obtained by concentrating a 20 wt% Nafion 1100EW solution obtained from Solution Technology. The concentrated Nafion solution described above had a viscosity of 890 poise as measured by a rotational viscometer equipped with a # 4 spindle (Brookfield LVT model) at 6 rpm.

The catalyst ink paste used to form the external electrode catalyst layer was prepared by mixing:
Platinum Black (HiSpec 1000 from Alpha Eisal) is 18.8% by weight
13.8% deionized water
1.1% polytetrafluoroethylene powder with a particle size of 1 micron (supplied by Aldrich Chemical Company)
5% Nafion (in alcohol and water mixture) 1100EW solution (Solution Technology) 66.3%

  The process line speed was 1 m / min and the extrusion temperature was ambient (approximately 72 ° F./22° C.). The extrusion rate through the single layer coating die to form the internal electrocatalyst layer was 0.15 ml / min. The set point of the infrared dryer for the ink layer was 400 ° C. After exiting the dryer, the catalyst coated fibers were passed through a coated die filled with 20 wt% Nafion solution to apply a thin layer of 20 wt% Nafion solution over the internal electrode catalyst layer. This thin Nafion layer was dried by passing it through a hot air tube supplied with 100-110 ° C. heated air. A thin layer of 20 wt% Nafion solution was used to improve the adhesion between the inner electrocatalyst layer and the next layer of concentrated 32 wt% Nafion.

  After exiting the hot air dryer, a concentrated 32% Nafion solution was applied using a second single layer coating die. The Nafion solution was pumped at a rate of 0.48 ml / min. The second Nafion layer was dried with an infrared dryer at 375 ° C. Next, the Nafion-coated fiber was passed through a belt-drawing device to a winding device that winds the fiber around a winding frame. The Nafion coated fibers consisted at this point of 0.020 "wire, a 10-15 micron internal electrocatalyst layer, and an approximately 50 micron Nafion membrane layer.

The Nafion-coated fiber was cut to a desired length, and the external electrode catalyst layer was formed by brushing the catalyst ink paste on the Nafion membrane layer. The catalyst ink was dried at 70 ° C. for 30 minutes and then at 125 ° C. for 1 hour. The multilayer fiber was then placed in water for a sufficient amount of time so that the Nafion membrane layer swelled, thereby allowing the 0.020 "wire to be separated from the Nafion membrane layer and the inner and outer electrocatalyst layers. The peeled 0.020 "wire was then removed therefrom to form a hollow fiber comprising a hollow microfibrous Nafion membrane, an internal electrode catalyst layer, and an external electrode catalyst layer. The hollow fibers are then placed in a hot dilute peroxide solution for 1 hour to remove impurities, then placed in 1N sulfuric acid overnight to restore all exchangeable sites to the H ⁺ form, and deionized water. The final washing was performed at 70 ° C. for 10 minutes.

  As disclosed in US patent application Ser. No. 10 / 188,471 filed Jul. 2, 2002, the contents of which are incorporated herein by reference in their entirety for all purposes, A 0.015 "diameter titanium / copper clad wire (i.e., internal current collector) is inserted into each of the hollow fibers, with a 0.005 passage between the internal current collector and the internal electrode catalyst layer. In order to form a finished microfibrous fuel cell, an external current collector was secured to each external surface of the hollow fiber by wrapping a thin titanium wire around it.

One current density of the microfibrous fuel cell, which was about 6 "long and 3 cm ² in surface area, was tested at ambient conditions. Both supplied dry hydrogen to the barrel side at a rate of 20 cc / min. Then, air was supplied to the hole side of the microfibrous fuel cell, and the current density was about 135 to 140 mA / cm ² at 0.5 volt, and the current density was 215 to 220 mA / cm at 0.4 volt. cm ² .

  Although the invention has been described herein with reference to specific embodiments, features, and aspects, the invention is not limited thereby, but rather other modifications, variations, applications, and implementations. It is recognized that the usefulness extends to forms, and thus all of the above other modifications, variations, applications, and embodiments should be considered within the spirit and scope of the present invention. It will be.

Brief Description of Drawings
It is a perspective view of the process which manufactures the hollow fiber-like membrane separator by one Embodiment of this invention. 2 is a cross-sectional view of two fibrous substrate structures of different embodiments, each of which is coated with a layer of film-forming material. 2 is a cross-sectional view of two fibrous substrate structures of different embodiments, each of which is coated with a layer of film-forming material. It is sectional drawing of the process which manufactures the hollow fiber-like membrane separator by one Embodiment of this invention. 1 is a perspective view of a process for manufacturing a hollow fibrous membrane separator having an internal current collector therein, according to one embodiment of the present invention. FIG. 1 is a cross-sectional view of a fibrous substrate structure coated with a layer of film-forming material according to one embodiment of the present invention. 1 is a cross-sectional view of a process for producing a hollow fibrous membrane separator having an internal current collector therein, according to one embodiment of the present invention. FIG. 6 is a cross-sectional view of a process for producing a hollow fibrous membrane separator having an internal current collector therein, according to another embodiment of the present invention. 1 is a cross-sectional view of a process for producing a hollow fibrous membrane separator having an internal current collector and an internal electrode catalyst layer therein, according to one embodiment of the present invention. 1 is a cross-sectional view of a process for producing a hollow fiber membrane separator having an internal current collector, an internal electrode catalyst layer, and an external electrode catalyst layer according to an embodiment of the present invention. It is sectional drawing of the microfibrous fuel cell structure formed by the method of this invention. FIG. 5 is a perspective view of an extrusion process in which an additional layer of material is applied to thin fibers.

Claims (74)

A method for producing a microfibrous fuel cell structure, comprising:
(A) providing a fibrous substrate structure comprising at least one detachable solid phase substrate material;
(B) coating a layer of film-forming material on the fibrous substrate structure;
(C) then removing said at least one removable substrate material so as to form a hollow fibrous membrane separator having a hole side and a body side;
The microfibrous fuel cell structure includes:
(1) an internal current collector;
(2) an external current collector,
(3) A hollow fiber membrane separator comprising an electrolyte medium and electrically contacting an internal current collector on the hole side and an external current collector on the body side, wherein the hollow fiber The hollow fiber membrane separator further comprising a lumen through which fluid can pass through the pore side of the membrane separator,
(4) an internal electrode catalyst layer covering the pore side of the hollow fibrous membrane separator;
(5) A method comprising an external electrode catalyst layer covering the body side of the hollow fibrous membrane separator.   The method of claim 1, wherein the at least one removable substrate material is selected from the group consisting of sublimable materials, meltable materials, and soluble materials.   The at least one removable substrate material comprises a soluble material selected from the group consisting of an acid soluble material, an alkali soluble material, an organic solvent soluble material, and a water soluble material. The method described in 1.   The method of claim 1, wherein the at least one removable substrate material comprises a water soluble polymeric material selected from the group consisting of polyvinyl pyrrolidone, polyvinyl alcohol, and polyethylene glycol.   The method of claim 1, wherein the at least one removable substrate material comprises polyvinylpyrrolidone.   The method of claim 1, wherein the at least one removable substrate material comprises polyvinyl alcohol.   The method of claim 1, wherein the fibrous substrate structure consists essentially of the at least one removable solid substrate material. (D) attaching an internal current collector to the hole side of the hollow fiber membrane separator;
(E) attaching an external current collector to the trunk side of the hollow fibrous membrane separator;
(F) forming an internal electrode catalyst layer on the pore side of the hollow fiber membrane separator;
(G) forming an external electrode catalyst layer on the body side of the hollow fibrous membrane separator;
The steps (d) to (g) can be performed in any order, or two or more of the steps can be performed in any combination at the same time. The method described in 1.   The fibrous substrate structure includes a removal interface in contact with at least a portion of the one or more removable substrate materials, the removal interface promoting removal of the at least one substrate material; The method of claim 1.   The removal interface of claim 9, wherein the removal interface includes an open cavity in the at least one removable substrate material through which a removal fluid can pass to remove the removable substrate material. Method.   The fibrous substrate structure includes a first detachable solid phase substrate material and a second detachable solid phase substrate material, the first detachable substrate material being a second detachable substrate material. The method of claim 1, wherein the method is more easily detachable than a solid phase substrate material.   The first removable substrate material is removed prior to removal of the second removable substrate material to form a removal interface that facilitates removal of the second removable substrate material. The method described in 1.   The method according to claim 1, wherein the fibrous substrate structure includes three or more types of removable substrate materials having different peelability, at least one of which is a solid phase.   The fibrous substrate structure includes an internal current collecting layer device and at least one layer of removable substrate material that covers the internal current collector ground so that the removable substrate material has been removed. 2. The method according to claim 1, wherein the membrane-forming material layer covering the fibrous substrate structure forms a hollow fibrous membrane separator having an internal current collector on its pore side. (D) attaching an external current collector to the trunk side of the hollow fibrous membrane separator;
(E) forming an internal electrode catalyst layer on the pore side of the hollow fibrous membrane separator;
(F) forming an external electrode catalyst layer on the body side of the hollow fiber membrane separator,
The steps (d) to (f) can be performed sequentially in any order, or two or more of the steps can be performed in any combination at the same time. The method described in 1.   15. The fibrous substrate structure includes a removal interface that contacts at least a portion of the layer of the removable substrate material, the removal interface facilitating removal of the removable substrate material. the method of.   The removal interface includes an open cavity in the layer of removable substrate material and is adjacent to the internal current collector through which a removal fluid passes to remove the removable substrate material. The method of claim 16, wherein   The fibrous substrate structure includes a first layer of a first removable substrate material that covers the top of the internal current collector, and a second removable layer that covers the first layer. 6. A second layer of solid phase substrate material, wherein the first removable substrate material is more easily removable than a second removable solid phase substrate material. 14. The method according to 14.   19. The first removable substrate material is removed prior to removal of a second removable substrate material to form a removal interface that facilitates removal of the second removable substrate material. The method described.   The fibrous substrate structure includes more than two layers of a detachable substrate material with different peelability covering the inner current collector, and an outermost layer includes a detachable substrate that is a solid phase. The method according to claim 14.   The fibrous substrate structure includes one or more soluble fibers placed adjacent to the internal current collector, and at least one layer of the removable substrate material comprises soluble fibers and an internal current collector 15. The method of claim 14, wherein both and the one or more soluble fibers comprise a material that has greater peelability than the removable substrate material. The fibrous substrate structure is
An internal current collector,
At least one layer of removable substrate material covering the internal current collector;
An internal electrocatalyst layer overlying at least one of the removable substrate material layers;
As a result, after the removable substrate material is removed, a film-forming material layer covering the fibrous substrate structure has an internal current collector on its hole side, and its film side on its hole side. The method according to claim 1, wherein a hollow fiber membrane separator having an internal electrode catalyst layer covering the top is formed. (D) attaching an external current collector to the trunk side of the hollow fibrous membrane separator;
(E) forming an external electrode catalyst layer on the body side of the hollow fiber membrane separator;
23. The method of claim 22, further comprising: steps (d)-(e) can be performed sequentially in any order or simultaneously.   The fibrous substrate structure includes a removal interface that contacts at least a portion of at least one layer of the removable substrate material, the removal interface facilitating removal of the removable substrate material. 23. The method according to 22.   The removal interface includes an open cavity in at least one layer of the removable substrate material and is adjacent to the internal current collector through which a removal fluid passes to remove the removable substrate material. 25. The method of claim 24, which can be removed.   The fibrous substrate structure includes a detachable substrate that includes two or more layers of a detachable substrate material having different releasability covering the inner current collector, and the outermost layer is a solid phase. 23. The method of claim 22, comprising.   The external electrode catalyst layer is coated on the membrane-forming material layer before the removable substrate material is removed, so that a hollow fibrous membrane separator formed thereafter is formed on the cylinder side. The method according to claim 22, wherein an external current collector is attached to the body side of the hollow fibrous membrane separator.   The method of claim 1, wherein the hollow fibrous membrane separator electrolyte medium comprises at least one solid electrolyte material.   The at least one solid electrolyte material includes a perfluorocarbon-sulfonic acid polymer, a polysulfone polymer, a perfluorocarboxylic acid polymer, a styrene-vinyl-benzene-sulfonic acid polymer, and a styrene-butadiene polymer. 30. The method of claim 28, comprising an ion exchange ceramic or ion exchange polymer selected from the group consisting of:   29. The method of claim 28, wherein the hollow fibrous membrane separator consists essentially of the at least one solid electrolyte material.   28. The method of claim 27, wherein the hollow fibrous membrane separator is microporous and the solid electrolyte material is impregnated into the micropores of the hollow fibrous membrane separator. A method for producing a microfibrous fuel cell structure, comprising:
(A) providing an internal current collector in a microfibrous form;
(B) forming at least one layer of removable substrate material on the internal current collector;
(C) forming an internal electrocatalyst layer on at least one layer of the removable substrate material;
(D) forming a film-forming material layer on the internal electrode catalyst layer;
(E) forming an external electrode catalyst layer on the film-forming material layer;
(F) removing at least one layer of the removable substrate material;
(G) attaching an external current collector to the external surface of the external electrode catalyst layer;
To form a microfibrous fuel cell structure, the microfibrous fuel cell structure comprising:
(1) internal and external current collectors;
(2) internal and external electrode catalyst layers;
(3) a hollow fibrous membrane separator formed by the membrane-forming material layer;
The hollow fibrous membrane separator includes an electrolyte medium and has a hole side and a body side, an internal current collector and an internal electrode catalyst layer on the hole side, and an external current collector and an external electrode on the body side A method further comprising a lumen having a catalyst layer and wherein the pore side of the hollow fibrous membrane separator is formed by removal of the removable substrate material through which fluid can pass.   In step (b), at least one layer of the removable substrate material is by a method selected from the group consisting of melt extrusion, solution extrusion, ink extrusion, spray coating, brush coating, dip coating and vapor deposition. The method of claim 32, wherein the method is formed. In step (b), at least one layer of the removable substrate material is formed by a melt extrusion method,
(I) providing a molten removable substrate material;
(Ii) extruding the molten removable substrate material onto an internal current collector to form a layer of a predetermined thickness;
(Iii) cooling the molten layer of removable substrate material for a sufficient period of time to form a solidified layer of the removable substrate material;
35. The method of claim 32, comprising:   35. The method of claim 34, wherein the cooling is performed either in air or in a liquid bath containing a liquid that does not interact with a removable substrate material or internal current collector. In step (b), at least one layer of the removable substrate material is formed by a solution extrusion method,
(I) providing a viscous solution of the removable substrate material;
(Ii) extruding the viscous solution onto an internal current collector to form a layer of a predetermined thickness;
(Iii) treating the layer of the sticky solution of the removable substrate material for a sufficient time to form a solidified layer of the removable substrate material;
35. The method of claim 32, comprising:   37. The method of claim 36, wherein the removable substrate material comprises a water soluble polymeric material and the viscous solution comprises a viscous aqueous solution of the water soluble material.   The desorbable substrate material comprises a polymeric material that is not soluble in water, and the viscous solution comprises a hydrocarbon solvent that dissolves the polymeric material and is subsequently removed during a drying step. Item 37. The method according to Item 36.   The viscous solution of the desorbable substrate material is formed at a high temperature and maintained at the high temperature during an extrusion step, and the processing step comprises the step of desorbing the desorbable substrate material from the solution. 40. The method of claim 36, comprising thermally induced phase separation.   33. In step (c), the internal electrode catalyst layer is formed by a method selected from the group consisting of ink extrusion, spray coating, brush coating, dip coating, chemical deposition, electrochemical deposition and vapor deposition. The method described in 1. In step (c), the internal electrode catalyst layer is formed by an ink extrusion molding method,
(I) providing an ink paste comprising an electrocatalytic material;
(Ii) extruding the ink paste on at least one layer of the removable substrate material to form a layer of a predetermined thickness;
(Iii) treating the layer of ink paste for a sufficient amount of time to form a solidified electrocatalyst layer;
35. The method of claim 32, comprising:   42. The method of claim 41, wherein the electrocatalyst material comprises a metal selected from the group consisting of platinum, gold, ruthenium, iridium, palladium, rhodium, nickel, iron, molybdenum, tungsten, niobium, and alloys thereof.   42. The method of claim 41, wherein the electrocatalyst material comprises a metal selected from the group consisting of platinum and platinum alloys.   42. The method of claim 41, wherein the ink paste further comprises a conductive material, an ion exchange polymeric material, a polymeric binder, and a solvent.   45. The method of claim 44, wherein the ink paste comprises an electrocatalytic material in an amount of about 5% to about 90% based on the total weight of the ink paste.   42. The method of claim 41, wherein the processing step comprises either thermally drying the ink paste or contacting the ink paste with a coagulant.   The film-forming material layer in step (d) is formed by a method selected from the group consisting of melt extrusion, solution extrusion, spray coating, brush coating, dip coating and vapor deposition. Method. In step (d), the film-forming material layer is formed by a solution extrusion molding method,
(I) providing a viscous solution of the film-forming material;
(Ii) extruding the viscous solution on the internal electrode catalyst layer to form a layer having a predetermined thickness;
(Iii) treating the layer of the viscous solution of the film-forming material for a sufficient time to form a solidified film-forming material layer;
35. The method of claim 32, comprising:   47. The method of claim 46, wherein the viscous solution comprises the film-forming material in an amount of about 10% to about 50% based on the total weight of the viscous solution.   The film forming material is selected from the group consisting of a perfluorocarbon-sulfonic acid polymer, a polysulfone polymer, a perfluorocarboxylic acid polymer, a styrene-vinyl-benzene-sulfonic acid polymer, and a styrene-butadiene polymer. 48. The method of claim 46, comprising an ion exchange polymer.   47. The method of claim 46, wherein the film-forming material comprises a perfluorosulfonate ionomer.   47. The method of claim 46, wherein the viscous solution comprises a perfluorosulfonate ionomer dissolved in a water-alcohol mixture.   51. The method of claim 50, wherein the viscous solution comprises the perfluorosulfonate ionomer in an amount of about 10% to about 50% based on the total weight of the viscous solution.   47. The method of claim 46, wherein the treating step comprises either thermally drying the viscous solution or contacting the viscous solution with a coagulant.   47. The method of claim 46, wherein the processing step comprises first thermally curing the viscous solution at a temperature above the glass transition temperature of the film-forming material, and then cooling the solution. In step (d), the film-forming material layer is formed by a dip coating method,
(I) providing a viscous solution of the film-forming material;
(Ii) dip-coating the viscous solution on the internal electrode catalyst layer to form a layer having a predetermined thickness;
(Iii) treating the layer of the viscous solution of the film-forming material for a sufficient time to form a solidified film-forming material layer;
35. The method of claim 32, comprising:   33. In step (e), the external electrode catalyst layer is formed by a method selected from the group consisting of ink extrusion, spray coating, brush coating, dip coating, chemical deposition, electrochemical deposition and vapor deposition. The method described in 1.   33. In step (f), at least one layer of the removable substrate material is removed by a method selected from the group consisting of sublimating, melting and dissolving the removable substrate in a solvent. The method described in 1.   The detachable substrate material comprises a soluble material selected from the group consisting of an acid soluble material, an alkali soluble material, an organic solvent soluble material and a water soluble material, and in step (f) The at least one layer of the removable substrate material is removed by dissolving the removable substrate material in a solvent selected from the group consisting of acids, alkalis, organic solvents and water. The method described.   The removable substrate material comprises a water soluble polymeric material, and in step (f), at least one layer of the removable substrate material is removed by immersing it in water. Item 33. The method according to Item 32.   59. The method of claim 58, wherein the water is heated to an elevated temperature in the range of about 40 <0> C to about 100 <0> C to facilitate removal of the removable substrate material.   33. The method of claim 32, adapted for continuous and automated production of multiple microfibrous fuel cell structures.   2. The method of claim 1 adapted for continuous and automated production of multiple microfibrous fuel cell structures. A method for producing a microfibrous electrochemical cell structure, comprising:
(A) providing a fibrous substrate structure comprising at least one detachable solid phase substrate material;
(B) coating a layer of film-forming material on the fibrous substrate structure;
(C) then removing the removable substrate material so as to form a hollow fibrous membrane separator having a hole side and a body side;
The microfibrous electrochemical cell structure comprises:
(1) an internal electrode;
(2) an external electrode;
(3) A hollow fibrous membrane separator that includes an electrolyte medium and is in electrical contact with an internal electrode on the hole side and an external electrode on the body side, and the hollow fibrous membrane separator The pore side of the body further includes a lumen that allows passage of fluid therethrough, the hollow fibrous membrane separator; and
Including methods.   64. The method of claim 62, wherein the microfibrous electrochemical cell structure comprises a microfibrous water electrolyzer.   64. The method of claim 62, wherein the microfibrous electrochemical cell structure comprises a microfibrous chloroalkali cell. A method for producing a microfibrous fuel cell structure, comprising:
(A) providing a core fiber comprising a solid material;
(B) forming at least one layer of a swellable polymer film-forming material on the core fiber;
(C) contacting at least one layer of the swellable polymer film-forming material with a swelling agent, so that at least one layer of the swellable polymer film-forming material expands and peels from the core fiber When,
(D) then removing the peeled core fibers so as to form a hollow fiber membrane separator having a hole side and a body side;
The microfibrous fuel cell structure includes:
(1) Internal current collector,
(2) External current collector,
(3) A hollow fibrous membrane separator that includes an electrolyte medium and is in electrical contact with the internal current collector on the hole side and with the external current collector on the body side, and the hollow The hollow side of the fibrous membrane separator further includes a lumen through which fluid can pass; and
(4) an internal electrode catalyst layer covering the pore side of the hollow fiber membrane separator;
(5) an external electrode catalyst layer covering the body side of the hollow fiber membrane separator;
Including methods.   66. The method of claim 65, wherein the swellable polymeric film-forming material comprises a proton exchange polymer.   66. The method of claim 65, wherein the swellable polymer film-forming material comprises a perfluorosulfonic acid polymer.   68. The method of claim 67, wherein the swelling agent comprises water and / or an organic solvent. A method for producing a microfibrous fuel cell structure, comprising:
(A) providing a core fiber comprising a solid material;
(B) forming an internal electrode catalyst layer on the core fiber;
(C) forming at least one layer of a swellable polymer film-forming material on the internal electrode catalyst layer;
(D) forming an external electrode catalyst layer on at least one layer of the swellable polymer film-forming material;
(E) contacting the swellable polymer film-forming material layer with a swelling agent to achieve its expansion, the core fiber from the swellable polymer film-forming material layer and from the inner and outer electrode catalyst layers; A step of causing peeling;
(F) The core fiber thus peeled so as to form a hollow fibrous membrane separator having a hole side and a body side, an internal electrode catalyst layer on the hole side, and an external electrode catalyst layer on the body side Step to remove
The microfibrous fuel cell structure includes:
(1) an internal current collector;
(2) an external current collector,
(3) A hollow fibrous membrane separator that includes an electrolyte medium and is in electrical contact with the internal current collector on the hole side and with the external current collector on the body side, and the hollow The hole side of the fibrous membrane separator, the hollow fibrous membrane separator further comprising a lumen through which fluid can pass,
(4) an internal electrode catalyst layer;
(5) an external electrode catalyst layer;
Including methods.   70. The method of claim 69, wherein the swellable polymeric film-forming material comprises a proton exchange polymer.   70. The method of claim 69, wherein the swellable polymer film-forming material comprises a perfluorosulfonic acid polymer.   72. The method of claim 71, wherein the swelling agent comprises water and / or an organic solvent.

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