JP2010232059A - Electrolyte membrane with catalyst layer for fuel cell, method of manufacturing membrane-electrode assembly for fuel cell using the same, and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte membrane with catalyst layer for a fuel cell which is superior in reproducibility, has superior moldability, can be producible even if there is no self-supporting film, and has a high proton conductivity in non-humidifying state by suppressing exudation of phosphate, to provide a method of manufacturing a membrane-electrode assembly for the fuel cell using the same, and to provide the fuel cell. <P>SOLUTION: The membrane-electrode assembly for the fuel cell 10 includes an electrolyte membrane 1 containing metal phosphate, catalyst layers 2, 3 arranged so as to pinch the electrolyte membrane 1, gas diffusion layers 4, 5 as a supporting base material which are arranged on the surface on opposite side to the face in contact with the electrolyte membrane 1 of respective catalyst layers 2, 3, and a filling layer 6 which covers at least the end face of the electrolyte membrane 1 and the end face of the respective catalyst layers 2, 3. The filling layer 6 contains at least any one kind of the metal phosphate or a binder. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an electrolyte membrane with a catalyst layer for a fuel cell, a method for producing a membrane / electrode assembly for a fuel cell using the same, and a fuel cell, and in particular, an electrolyte membrane with a catalyst layer for a fuel cell having a sealing layer. The present invention also relates to a method for producing a membrane / electrode assembly for a fuel cell and a fuel cell using the same.

In recent years, with increasing environmental awareness, fuel cells have attracted attention as clean energy that does not emit CO ₂ or pollutants. Of these, efforts are being made to develop a PEFC (solid polymer fuel cell) using a solid polymer electrolyte that has high energy efficiency and a temperature range of around 100 ° C. and is easy to handle for general use.

As a polymer electrolyte that conducts protons, perfluorosulfonic acid or the like that is generally known as Nafion (registered trademark) is used, but it conducts protons when the proton conduction mechanism is H ₃ O ^+. Since it is a vehicle (transportation) mechanism, it is necessary to provide a humidification mechanism, which causes a problem that the system becomes complicated.

  A PBI (polybenzimidazole) membrane impregnated with phosphoric acid is disclosed as an electrolyte that has improved the problem of humidification (see, for example, Patent Document 1). However, since 90% or more of this film is composed of liquid phosphoric acid, phosphoric acid, which is a strong acid, is likely to ooze out, liquid sealing must be performed strictly, and phosphorous is used in cell fabrication. There are problems such as difficulty in producing MEA (membrane / electrode assembly) due to acid seepage.

  On the other hand, a fuel cell using a metal phosphate as an electrolyte membrane or a catalyst layer as a proton conductive electrolyte having proton conductivity in a non-humidified state is known (for example, see Patent Document 2). In addition, a fuel cell is also disclosed in which a part of a metal phosphate is doped with another metal and a film having a binder is used as an electrolyte membrane (see, for example, Patent Documents 3 and 4).

JP 2001-510931 A JP 2005-294245 A JP 2008-53224 A JP 2008-53225 A JP-A-63-187575

  However, in the case of the above metal phosphate, phosphoric acid may be lost during the heat treatment at 350 ° C. or higher, which is necessary in the synthesis process, so the reproducibility of the product cannot be obtained, and the synthesis conditions can be controlled. There is a problem that it is difficult.

  Further, in the formation of the electrolyte membrane and the catalyst layer, since the metal phosphate is a powder, there is a problem that the moldability and the self-standing membrane property are poor.

  In addition, since electrolyte membranes and catalyst layers used in fuel cells contain free-type phosphoric acids, MEA is easily leached out of phosphoric acid, which is a strong acid, and leaching out of phosphoric acid when producing fuel cells. There is a problem that it is difficult to manufacture.

  Regarding the leaching of phosphoric acid, a fuel cell is known in which an electrolyte holding seal is applied to the peripheral edge of an electrode (see, for example, Patent Document 5). However, since the electrolyte holding seal used in this fuel cell is provided at the peripheral edge of the electrode, it is difficult to prevent the leaching of phosphoric acid from the electrolyte membrane.

  An object of the present invention is a fuel that has excellent reproducibility, good moldability, can be produced without a self-supporting film property, suppresses leaching of phosphoric acid, and has high proton conductivity in a non-humidified state It is an object to provide an electrolyte membrane with a catalyst layer for a battery, a method for producing a membrane / electrode assembly for a fuel cell using the same, and a fuel cell.

  In order to achieve the above object, an invention according to claim 1 is directed to an electrolyte membrane containing a metal phosphate, a catalyst layer disposed so as to sandwich the electrolyte membrane, and the electrolyte membrane of each of the catalyst layers, A substrate disposed on a surface opposite to the surface in contact with the substrate, and a sealing layer covering at least an end surface of the electrolyte membrane and each of the end surfaces of the catalyst layer, and the sealing layer includes at least a metal phosphorous layer. An electrolyte membrane with a catalyst layer for a fuel cell, comprising any one of an acid salt and a binder.

  The invention according to claim 2 is a substrate, a catalyst layer disposed on the substrate, an electrolyte membrane including a metal phosphate disposed on the catalyst layer, and at least the catalyst layer. And a sealing layer covering an end surface of the electrolyte membrane, wherein the sealing layer contains at least one of a metal phosphate and a binder. It is.

  The invention according to claim 3 is a substrate, a catalyst layer disposed on the substrate, an electrolyte membrane including a metal phosphate disposed on the catalyst layer, and the electrolyte membrane. A catalyst layer disposed on a surface opposite to the substrate side; and at least an end face of each of the catalyst layers and an end face of the electrolyte membrane, wherein the end stop layer includes at least metal phosphoric acid. It is an electrolyte membrane with a catalyst layer for a fuel cell, which contains any one of a salt and a binder.

  The invention according to claim 4 is the electrolyte membrane with a catalyst layer for a fuel cell according to any one of claims 1 to 3, wherein the base material is a gas diffusion layer.

  The invention according to claim 5 is the electrolyte membrane with a fuel cell catalyst layer according to any one of claims 1 to 3, wherein the substrate is a transfer substrate.

  The invention according to claim 6 is the electrolyte membrane with a catalyst layer for a fuel cell according to any one of claims 1 to 5, wherein the sealing layer contains a metal phosphate.

  The invention according to claim 7 is characterized in that the sealing layer, the electrolyte membrane, and the catalyst layer contain the same kind of binder as each other. It is an electrolyte membrane with a catalyst layer for a fuel cell.

  In the invention according to claim 8, the electrolyte membrane and the catalyst layer include a binder of a different type from the binder used for the sealing layer, and at least one kind of used for the electrolyte membrane and the catalyst layer. The electrolyte membrane with a catalyst layer for a fuel cell according to any one of claims 1 to 6, wherein the binder has a glass transition point or a softening point which is 50 ° C or less different from that of the binder used for the sealing layer. It is.

  The invention according to claim 9 is the fuel cell according to claim 8, wherein the binder used in the sealing layer is one selected from a cycloolefin polymer, a polyamideimide, and a polyimide. It is an electrolyte membrane with a catalyst layer.

  The invention according to claim 10 provides a step of preparing a gas diffusion layer, a step of forming a sealing layer in a frame shape on the gas diffusion layer, and the gas diffusion layer surrounded by the sealing layer. A step of forming a catalyst layer on the surface of the substrate, a step of forming an electrolyte membrane on the catalyst layer, a step of forming the catalyst layer on the electrolyte membrane, and the gas on the electrolyte membrane and the sealing layer And a step of forming a diffusion layer. A method for producing a membrane / electrode assembly for a fuel cell.

  The invention described in claim 11 is a fuel comprising a step of joining two of the electrolyte membranes with a catalyst layer for fuel cells described in claim 2 with the electrolyte membrane side facing each other. This is a method for producing a membrane-electrode assembly for a battery.

  The invention described in claim 12 includes the step of forming a gas diffusion layer on the surface side where the catalyst layer of the electrolyte membrane with a catalyst layer for fuel cell according to claim 3 is exposed. A method for producing a membrane-electrode assembly for a fuel cell.

  A thirteenth aspect of the invention is a fuel cell membrane / electrode assembly manufactured by the method for manufacturing a fuel cell membrane / electrode assembly according to any one of the tenth to twelfth aspects, and a pair. The fuel cell membrane-electrode assembly is sandwiched between the separators.

  According to the present invention, the fuel has excellent reproducibility, good moldability, can be produced without self-supporting film property, suppresses seepage of phosphoric acid, and has high proton conductivity in a non-humidified state. An electrolyte membrane with a catalyst layer for a battery, a method for producing a membrane / electrode assembly for a fuel cell using the same, and a fuel cell can be provided.

1 is a schematic cross-sectional view of a fuel cell membrane-electrode assembly according to a first embodiment of the present invention. The typical sectional view of the electrolyte membrane with a catalyst layer for fuel cells concerning a 2nd embodiment of the present invention. The typical sectional view of the electrolyte membrane with a catalyst layer for fuel cells concerning a 3rd embodiment of the present invention. The typical sectional view of the electrolyte membrane with a catalyst layer for fuel cells with a transfer substrate concerning a 4th embodiment of the present invention. The typical sectional view of the electrolyte membrane with a catalyst layer for fuel cells with a transfer substrate concerning a 5th embodiment of the present invention. The typical sectional view of the electrolyte membrane with a catalyst layer for fuel cells with a transfer substrate concerning a 6th embodiment of the present invention. It is explanatory drawing of the manufacturing method of the membrane electrode assembly for fuel cells which concerns on the 1st Embodiment of this invention, Comprising: (a) Process drawing which prepares a gas diffusion layer, (b) A frame on a gas diffusion layer A process diagram for forming a sealing layer in a shape, (c) a process diagram for forming a catalyst layer on the surface of the gas diffusion layer surrounded by the sealing layer, (d) a process diagram for forming an electrolyte membrane on the catalyst layer, (E) Process drawing which forms a catalyst layer on an electrolyte membrane. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating a method for manufacturing a fuel cell membrane / electrode assembly according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating a method for manufacturing a fuel cell membrane / electrode assembly according to a first embodiment of the present invention. FIG. 10 is a schematic cross-sectional view of a fuel cell according to a seventh embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiments of the present invention described below exemplify materials and manufacturing methods for embodying the technical idea of the present invention. The technical idea of the present invention includes the following materials and manufacturing methods. It is not something specific. The technical idea of the present invention can be variously modified within the scope of the claims.

  In the description of the following drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, differ from actual ones, and also include portions having different dimensional relationships and ratios between the drawings.

[First embodiment]
(Fuel cell membrane / electrode assembly)
A fuel cell membrane / electrode assembly according to a first embodiment of the present invention will be described with reference to FIG. A fuel cell membrane / electrode assembly 10 according to a first exemplary embodiment of the present invention includes an electrolyte membrane 1 containing a metal phosphate, catalyst layers 2 and 3 disposed so as to sandwich the electrolyte membrane 1, and Gas diffusion layers 4 and 5 as supporting substrates disposed on the surface opposite to the surface in contact with the electrolyte membrane 1 of each of the catalyst layers 2 and 3, and at least the end surface of the electrolyte membrane 1 and the catalyst layers 2 and 3 respectively. And a sealing layer 6 covering the end face of the. The sealing layer 6 contains at least one of a metal phosphate and a binder.

(Electrolyte membrane)
The electrolyte membrane 1 according to the present embodiment is made of a proton conductive electrolyte composed of a metal phosphate and phosphoric acid.

  Examples of the metal phosphate include compounds such as orthophosphate and pyrophosphate. Specific examples include tin phosphate, zirconium phosphate, cesium phosphate, and the like. Preferably, a pyrophosphate in which a part of a metal such as tin or cesium is substituted with a doping metal element such as indium, aluminum, or antimony is preferable.

  In the present embodiment, the metal phosphate is preferably composed of a compound represented by the following formula (1).

M _1-x N _x P ₂ O ₇ (1)
(Where M and N are metal elements, X is 0 ≦ X <0.5, and M is selected from the group consisting of Zr, Cs, Sn, Ti, Si, Ge, Pb, Ca, Mg, and Al. N is a doping metal element and is one selected from the group of Al, In, B, Ga, Sc, Yb, Ce, La and Sb.)

  The metal phosphate according to this embodiment can be synthesized by heating and heat-treating one or more metal oxides and phosphoric acid.

  Here, phosphoric acids (hereinafter also simply referred to as “phosphoric acid”) refer to orthophosphoric acid and phosphoric acid condensates. Examples of phosphoric acid condensates include pyrophosphoric acid, triphosphoric acid, metaphosphoric acid (polyphosphoric acid), and the like. Is mentioned.

  The metal oxide is not particularly limited as long as it can generate phosphoric acid and a crystalline salt. For example, the oxide which consists of the following metal elements can be mentioned. That is, it is a metal element such as Zr, Cs, Sn, Ti, Si, Ge, Pb, Ca, Mg, and Al.

  You may dope the metal different from a main metal by using the said metal as a main metal. When a doped metal is used, it is desirable to use Sn, Cs, Ti and Zr from the viewpoint of stability as a phosphate among the main metals.

  As the dope metal, for example, when Sn is used as the main metal, In and Al are suitable because they can be dissolved in the main metal. The mixing ratio of the main metal and the doped metal varies depending on the solid solubility limit, but when Sn is used as the main metal and In is used as the doped metal, for example, a range of Sn: In = 7: 3 to 9.8: 0.2 is desirable.

  The proton conductive electrolyte according to the present embodiment is composed of a composite phosphate obtained by heat-treating a metal phosphate and phosphoric acid. By heat-treating the metal phosphate and phosphoric acid, proton conductivity is exhibited and a composite phosphate is obtained and becomes structurally strong.

  The above complex phosphate has [M] and [N] as the number of atoms of the metal element and the metal element of the metal phosphate, respectively, and the number of phosphorus atoms of the metal phosphate and the number of phosphorus atoms of the phosphoric acid. When the total of [P] is taken, it is preferable to satisfy | fill following formula (2).

2 <[P] / ([M] + [N]) ≦ 4 (2)
More preferably, it is preferable to satisfy | fill following formula (3).

    2.4 ≦ [P] / ([M] + [N]) ≦ 3.2 (3)

  By satisfy | filling said Formula (2), while high proton conductivity is acquired, a moldability will become favorable.

(binder)
The electrolyte membrane 1 may contain a binder. Moreover, an electrolyte membrane excellent in mechanical strength can be obtained by casting a paste obtained by adding a binder to metal phosphate.

  The binder used preferably has, for example, acid resistance at a pH of about 1 to 3 and heat resistance at a temperature of about 100 to 300 ° C. Further, it may have proton conductivity.

  Such a binder is preferably a fluorine-based or hydrocarbon-based polymer, or a fluorine-based or hydrocarbon-based ionomer.

  Fluoropolymers include fluorine such as tetrafluoroethylene (PTFE), polyvinylidene fluoride, ethylene tetrafluoride-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA). Resin or the like can be used.

  The hydrocarbon polymer is a polymer having a hydrocarbon compound as a main skeleton, and also includes nitrogen-containing compounds and sulfur compounds such as polyimide, polyamideimide, polystyrene sulfide, polybenzimidazole and the like. Moreover, inorganic components, such as Si, may be contained.

  Examples of the fluorine ionomer include perfluorosulfonic acid systems such as Nafion (registered trademark) of DuPont, Flemion (registered trademark) of Asahi Glass Co., and Aciplex (registered trademark) of Asahi Kasei.

  Hydrocarbon ionomers include polyarylene ether sulfonic acid, polystyrene sulfonic acid, syndiotactic polystyrene sulfonic acid, polyphenylene ether sulfonic acid, modified polyphenylene ether sulfonic acid, polyether sulfone sulfonic acid, polyether ether ketone sulfonic acid, and polyphenylene. Examples thereof include sulfide sulfonic acid.

  The binder may be an ionic liquid. The ionic liquid is not particularly limited as long as proton conductivity is not hindered. Examples of the ionic liquid include a fluorohydrogenate type ionic liquid and a diethylmethylammonium trifluoromethanesulfonic acid ionic liquid.

  The binder may be a cellulosic polymer. Examples of the cellulose polymer include methyl cellulose, carboxymethyl cellulose, and cellulose acetate.

  The binder mentioned above may use only 1 type and may use several types.

  Among these binders, PTFE, polyvinylidene fluoride, perfluorosulfonic acid, and cellulose acetate are preferably used from the viewpoint of durability and binding properties.

  The thickness of the electrolyte membrane 1 is not limited, but is usually about 20 to 1000 μm, and preferably about 30 to 300 μm from the viewpoint of strength.

(Catalyst layer)
The catalyst layers 2 and 3 in the present embodiment are composed of a proton conductive electrolyte and a catalyst composed of a metal phosphate and phosphoric acid.

  The catalyst is not particularly limited as long as it is a substance that promotes the anode and cathode reactions in the fuel cell. For example, platinum-supported carbon, platinum-ruthenium-supported carbon, platinum-cobalt-supported carbon, gold-supported carbon, silver-supported carbon, metal-supported carbon such as iron-cobalt-nickel-supported carbon, platinum black, platinum-ruthenium black, platinum- Examples thereof include fine metal particles such as cobalt black, gold black and silver black, and inorganic substances such as molybdenum carbide. Of these, platinum-supporting carbon with high catalytic activity, molybdenum carbide with low phosphoric acid poisoning, and the like are suitable.

  The catalyst layers 2 and 3 may contain a binder. The catalyst layers 2 and 3 can be formed by using only metal phosphate and a catalyst, but by adding a binder to these to form a paste, the catalyst has excellent mechanical strength. A layer can be obtained. The binder mentioned above can be used as the binder.

  The type of binder used for the catalyst layers 2 and 3, the type of solvent, and the blending ratio may be the same as or different from those of the electrolyte membrane 1. In the case where the binder used for the electrolyte membrane 1 and the binder used for the catalyst layers 2 and 3 are of different types, at least one contained in the electrolyte membrane 1 and the catalyst layers 2 and 3 from the viewpoint of adhesion between the electrolyte membrane 1 and the catalyst layers 2 and 3. The type of binder preferably has a glass transition point (Tg) or softening point difference of about 50 ° C. or less. Thereby, when the catalyst layers 2 and 3 and the electrolyte membrane 1 are bonded by hot pressing or the like, the adhesiveness is good even at the same hot pressing temperature.

  The thicknesses of the catalyst layers 2 and 3 may be appropriately determined in consideration of the type of electrode base material, the thickness of the electrolyte membrane, and the like. The thickness is, for example, about 20 to 3000 μm, preferably about 30 to 2000 μm.

(Gas diffusion layer)
The gas diffusion layers 4 and 5 are not particularly limited as long as they are conductive porous. For example, carbon paper, carbon cloth, carbon felt or the like is used. Moreover, you may use what performed the water-repellent process to these. Further, in order to prevent penetration when a catalyst paste is applied to the gas diffusion layers 4 and 5, it is desirable to use a gas diffusion layer provided with a planarization layer made of carbon black, PTFE, or the like.

  The thickness of the gas diffusion layers 4 and 5 is, for example, about 20 to 400 μm, preferably about 100 to 300 μm.

(Sealing layer)
As shown in FIG. 1, the sealing layer 6 according to the present embodiment covers at least the end face of the electrolyte membrane 1 and the end faces of the catalyst layers 2 and 3. The thickness of the sealing layer 6 is preferably formed so as to be the sum of the thicknesses of the catalyst layers 2 and 3 and the electrolyte membrane 1.

  The sealing layer 6 contains at least one of a metal phosphate and a binder. It is preferable to contain a metal phosphate since the adhesion between the catalyst layers 2 and 3 and the electrolyte membrane 1 is excellent.

  When metal phosphate is used, the content of metal phosphate is 5% to 50%, preferably 5% to 30%. If the content of the metal phosphate exceeds 50%, the proton conductivity is increased and there is a possibility of short-circuiting.

  As the metal phosphate or binder used in the sealing layer 6, the metal phosphate or binder used in the above electrolyte membrane 1 can be used. The type of binder, the type of solvent, and the mixing ratio used in the sealing layer 6 may be the same as or different from the type of binder used in the catalyst layer and the electrolyte membrane, the type of solvent, and the mixing ratio.

  When the binder used for the sealing layer 6 is different from the binder used for the electrolyte membrane 1 and the catalyst layers 2, 3, the glass transition point (Tg) or softening of at least one binder contained in the binder used for the sealing layer 6 The point difference is preferably 50 ° C. or less. Thereby, when the sealing layer 6 and the electrolyte membrane 1 and the catalyst layers 2 and 3 are bonded by hot pressing or the like, the adhesion is good even at the same hot pressing temperature.

  The water repellency of the binder used in the sealing layer 6 is preferably higher than the binder used in the catalyst layers 2 and 3 and the electrolyte membrane 1. For this reason, the difference in contact angle between the binder used in the sealing layer 6 and the binder used in the catalyst layers 2 and 3 and the electrolyte membrane 1 is, for example, usually about 10 degrees or more, preferably about 30 degrees or more. There should be. Thereby, exudation of free phosphoric acid in the electrolyte membrane 1 and the catalyst layers 2 and 3 can be prevented, and water can be prevented from entering the electrolyte membrane 1 and the catalyst layers 2 and 3 from the outside.

  Examples of the binder used for the sealing layer 6 include cycloolefin polymers, polyamide imides, and polyimides that are excellent in water repellency. Preferably, a cycloolefin polymer having higher water repellency is used.

  The sealing layer 6 covers the end face of the electrolyte membrane 1 and the end faces of the catalyst layers 2 and 3, so that the seepage of free phosphoric acid in the electrolyte membrane 1 and the catalyst layers 2 and 3 can be prevented.

(Manufacturing method of fuel cell membrane / electrode assembly)
As shown in FIG. 7, the method for manufacturing a fuel cell membrane / electrode assembly according to the present embodiment includes a step of preparing a gas diffusion layer 4 and a sealing layer 6 in a frame shape on the gas diffusion layer 4. A step of forming, a step of forming the catalyst layer 2 on the surface of the gas diffusion layer 4 surrounded by the sealing layer 6, a step of forming the electrolyte membrane 1 on the catalyst layer 2, and a catalyst layer on the electrolyte membrane 1 3 and a step of forming a gas diffusion layer 5 on the electrolyte membrane 1 and the sealing layer 6.
This will be described in detail below.

(A) First, a metal phosphate is prepared as follows.
Each metal oxide, metal hydroxide, metal chloride, or metal nitrate containing a main metal such as tin and a doping metal such as indium and liquid phosphoric acid are mixed in a predetermined number of moles. Next, water is added thereto, and the mixture is stirred and dispersed at a temperature of about 100 to 300 ° C. using a stirrer or the like for about 1 to 3 hours. This dispersion is put in a crucible and fired at a temperature of about 300 to 700 ° C., for example. The firing time is, for example, about 1 to 3 hours. Since phosphoric acid may disappear in the high temperature state, it is desirable that the number of moles of liquid phosphoric acid is large, for example, about 1.1 to 1.5 times the molar equivalent.

  In order to avoid the problem of loss of phosphoric acid during firing, solid phosphoric acid may be used instead of liquid phosphoric acid. In the case of using solid phosphoric acid, for example, using ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, or the like, each metal oxide containing a main metal such as tin and a doping metal such as indium is formed in a predetermined molar amount. Mix by number. As the metal oxide, an oxide containing a main metal and an oxide containing a doping metal may be mixed at a molar ratio of the main metal to the doping metal of, for example, about 9: 1 to 1: 1. These are put into a crucible and fired at a temperature of about 300 to 650 ° C. for about 1 to 3 hours. Subsequently, the product obtained by baking can be pulverized in an agate bowl to obtain a desired metal phosphate.

  By using solid phosphoric acid, a molar equivalent of phosphoric acid reacts with the metal oxide, and the excess is volatilized at a high temperature, so that excess phosphoric acid does not adhere and a reproducible metal phosphate can be obtained. it can.

  It can also be produced by a coprecipitation method. For example, the molar ratio of a main metal ion such as tin and a doping metal ion such as indium is desired by adding an excessive amount of phosphoric acid to a phosphoric acid solution mixed in a ratio of about 9: 1 to 1: 1, for example. The metal phosphate can be precipitated. According to the coprecipitation method, a highly uniform powder can be prepared by simultaneously precipitating a plurality of types of hardly soluble salts from a solution containing a plurality of desired metal ions.

(B) Next, a sealing layer paste is prepared using the obtained metal phosphate. The sealing layer paste is pulverized in an agate bowl or the like with the above-mentioned metal phosphate, mixed with liquid phosphoric acid, and then heat treated, and the heat treated metal phosphate and phosphoric acid mixture (composite) It can be obtained by adding a binder or the like to (phosphate) and mixing and dispersing with a disperser such as an ultrasonic disperser, a homogenizer, or a planetary ball mill.

  The heat treatment temperature is, for example, about 50 to 300 ° C., preferably about 100 to 250 ° C. When the heat treatment temperature is about 50 to 300 ° C., water contained in phosphoric acid can be removed, and volatilization of phosphoric acid can be prevented. The heat treatment time is, for example, about 10 minutes to 5 hours, preferably about 10 minutes to 3 hours.

  The compounding amount of the metal phosphate and the phosphoric acid is 5: 0.2 to 5: 2, preferably 5: 0.3 to 5: 1.2, more preferably 5: 0.8 to 5: 1 by mass ratio. Most preferably, it is adjusted to 5: 0.9.

(C) Next, as shown in FIG. 7A, a gas diffusion layer 4 such as carbon paper is prepared.

(D) Next, as shown in FIG. 7B, the sealing layer paste is applied onto the gas diffusion layer 4 by screen printing and dried into a rectangular frame shape to form the sealing layer 6. . The method for forming the sealing layer 6 on the gas diffusion layer 4 is not limited to screen printing. For example, knife coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater. General methods such as a rolling method and a dispenser can be applied.

(E) Next, as shown in FIG. 7 (c), the catalyst paste obtained by pasting the catalyst containing the metal phosphate is applied and dried on the gas diffusion layer 4 in the frame of the sealing layer 6. A catalyst layer 2 is formed.

  The catalyst paste can be produced in the same manner as the above-mentioned sealing layer paste. That is, the metal phosphate is pulverized in an agate bowl, etc., mixed with liquid phosphoric acid, and subjected to heat treatment in the same manner as described above, and platinum-supported carbon or the like is added to the mixture of metal phosphate and phosphoric acid subjected to the heat treatment. It can be prepared by adding a predetermined amount of catalyst and binder.

The coating amount of the catalyst paste, for example, when using a platinum-supported carbon, about 0.1 to 1.0 mg / cm ² of about the amount of supported platinum, preferably, from about 0.3~0.6mg / cm ² of about It is good to be.

  When a binder is used, the mass ratio (solid content) of (catalyst) to (mixture of metal phosphate and phosphoric acid and binder) (solid content) is 1: 2 to 1: 0.1, preferably 1: 1 to 1: 0.25. In this case, a solvent may be added to the binder solution or dispersion. A solvent that does not aggregate the binder is used. Specific examples include water, ethanol, methanol, 1-butanol, t-butanol, propanol, N-methylpyrrolidone, dimethylacetamide, and the like.

  The method for applying the catalyst paste to the gas diffusion layer 4 is not particularly limited, and for example, screen printing, blade coating, die coating, spray coating, dispenser coating, and inkjet coating can be used. Of these, it is preferable to use screen printing or blade coating because of the simplicity of the catalyst paste.

(F) Next, as shown in FIG. 7 (d), the electrolyte membrane paste is formed by coating and drying the electrolyte membrane paste on the catalyst layer 2. The electrolyte membrane paste can be produced in the same manner as the above-mentioned sealing layer paste.

(G) Next, as shown in FIG. 7 (e), the catalyst paste is applied and dried on the electrolyte membrane 1 in the frame of the sealing layer 6 in the same manner as above to form the catalyst layer 3.

(H) Finally, a gas diffusion layer 5 such as carbon paper is formed on the catalyst layer 3 and the sealing layer 6 to complete the fuel cell membrane / electrode assembly 10 shown in FIG.

  According to the present embodiment, since the sealing layer 6 covers the end face of the electrolyte membrane 1 and the end faces of the catalyst layers 2 and 3, the reproducibility is excellent, the moldability is good, and there is no self-standing film property. However, it is possible to provide a membrane / electrode assembly for a fuel cell that suppresses the seepage of phosphoric acid and has high proton conductivity in a non-humidified state.

[Second Embodiment]
(Electrolyte membrane with catalyst layer for fuel cells)
As shown in FIG. 2, the electrolyte membrane 11 with a catalyst layer for a fuel cell according to the second embodiment of the present invention includes a gas diffusion layer 4, a catalyst layer 2 disposed on the gas diffusion layer 4, and a catalyst. An electrolyte membrane 1 including a metal phosphate disposed on the layer 2 and a sealing layer 6 covering at least the catalyst layer 2 and the end face of the electrolyte membrane 1 are provided. The sealing layer 6 contains at least one of a metal phosphate and a binder.

  It is preferable that the exposed surface (surface opposite to the gas diffusion layer 4 side) of the electrolyte membrane 1 and the sealing layer 6 is the same plane. As a result, the electrolyte membrane 11 with catalyst layer can be satisfactorily bonded when the membrane-electrode assembly is manufactured by arranging the electrolyte membrane 1 with catalyst layer 11 so that the electrolyte membrane 1 faces each other.

  The method for manufacturing an electrolyte membrane with a catalyst layer for a fuel cell according to the second embodiment is different from the manufacturing method according to the first embodiment in that the heights of the electrolyte membrane 1 and the sealing layer 6 are uniform. The others are the same as in the manufacturing methods (a) to (f) of the first embodiment, and a duplicate description is omitted.

  In the method for manufacturing an electrolyte membrane with a catalyst layer for a fuel cell according to the second embodiment, electrolyte membrane paste is applied to the inside of the sealing layer 6 formed in a frame shape on the gas diffusion layer 4. It can be manufactured by coating and drying by screen printing so that the height is the same.

  According to the present embodiment, since the sealing layer 6 covers the end face of the electrolyte membrane 1 and the end face of the catalyst layer 2, the reproducibility is excellent, the moldability is good, and there is no self-supporting membrane property. It is possible to provide the electrolyte membrane 11 with a catalyst layer for a fuel cell that can be produced, suppresses the seepage of phosphoric acid, and has high proton conductivity in a non-humidified state.

[Third embodiment]
(Electrolyte membrane with catalyst layer for fuel cells)
As shown in FIG. 3, the electrolyte membrane 12 with a catalyst layer for a fuel cell according to the third embodiment of the present invention includes a gas diffusion layer 4, a catalyst layer 2 disposed on the gas diffusion layer 4, and a catalyst. An electrolyte membrane 1 containing a metal phosphate disposed on the layer 2, a catalyst layer 3 disposed on the surface opposite to the gas diffusion layer 4 side of the electrolyte membrane 1, and at least the end surfaces of the catalyst layers 2 and 3, respectively. And a sealing layer 6 covering the end face of the electrolyte membrane 1. The sealing layer 6 contains at least one of a metal phosphate and a binder.

  It is preferable that the exposed surface (surface opposite to the gas diffusion layer 4 side) of the catalyst layer 3 and the sealing layer 6 is the same plane. Thereby, when the gas diffusion layer 5 is arrange | positioned in the obtained electrolyte membrane 12 with a catalyst layer, and a membrane electrode assembly is manufactured, the gas diffusion layer 5 can be adhere | attached favorably.

  Since the manufacturing method of the electrolyte membrane with a catalyst layer for a fuel cell according to the third embodiment is the same as the manufacturing methods (a) to (g) of the first embodiment, a duplicate description is omitted.

  In the method for manufacturing an electrolyte membrane with a catalyst layer for a fuel cell according to the third embodiment, the catalyst layer 3 is formed in the frame of the seal layer 6 formed in a frame shape on the gas diffusion layer 4. It can be manufactured by coating and drying by screen printing so that the height is the same.

  According to the present embodiment, since the sealing layer 6 covers the end face of the electrolyte membrane 1 and the end faces of the catalyst layers 2 and 3, the reproducibility is excellent, the moldability is good, and there is no self-standing film property. However, the electrolyte membrane 12 with a catalyst layer for a fuel cell having high proton conductivity in a non-humidified state can be provided.

[Fourth embodiment]
(Electrolyte membrane with catalyst layer for fuel cell with transfer substrate)
As shown in FIG. 4, the electrolyte membrane 13 with a catalyst layer for a fuel cell with a transfer substrate according to the fourth embodiment of the present invention sandwiches the electrolyte membrane 1 containing a metal phosphate and the electrolyte membrane 1. Catalyst layers 2 and 3 arranged as described above, transfer substrates 7 and 8 arranged on the surface opposite to the surface in contact with the electrolyte membrane 1 of each of the catalyst layers 2 and 3, and at least the end face of the electrolyte membrane 1 and And a sealing layer 6 covering the end faces of the catalyst layers 2 and 3. The sealing layer 6 contains at least one of a metal phosphate and a binder.

  The electrolyte membrane 13 with a catalyst layer for a fuel cell with a transfer substrate according to the present embodiment replaces the gas diffusion layers 4 and 5 of the membrane-electrode assembly 10 in the first embodiment with transfer substrates 7 and 8. Since other than that is the same as the first embodiment, a duplicate description is omitted.

  The transfer base materials 7 and 8 are not particularly limited as long as they are in the form of a sheet or film, and examples thereof include metal foils and polymer films. In addition to these, coated paper such as art paper, coated paper, and light coated paper, and non-coated paper such as notebook paper and copy paper may be used. Moreover, in order to improve the peelability from the catalyst layers 2 and 3, you may provide a release layer, a peeling layer, etc.

  Polymer films include polyimide, polyethylene terephthalate (PET), polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, polyethylene naphthalate, etc. Is mentioned.

  Further, a heat-resistant fluororesin such as polyethylene tetrafluoroethylene copolymer (ETFE), FEP, PFA, PTFE, etc. can be used.

  The electrolyte membrane 13 with a catalyst layer for a fuel cell with a transfer substrate according to the present embodiment is replaced with the transfer substrate 7 in place of the gas diffusion layers 4 and 5 of the membrane / electrode assembly 10 according to the first embodiment. By using 8, it can be manufactured by the same method as shown in the first embodiment.

  According to the present embodiment, since the sealing layer 6 covers the end face of the electrolyte membrane 1 and the end faces of the catalyst layers 2 and 3, the reproducibility is excellent, the moldability is good, and there is no self-standing film property. The catalyst layer for a fuel cell with a transfer substrate can be produced, and can suppress the seepage of phosphoric acid and can produce an electrolyte membrane with a catalyst layer for a fuel cell that has high proton conductivity in a non-humidified state. The attached electrolyte membrane 13 can be provided.

[Fifth embodiment]
(Electrolyte membrane with catalyst layer for fuel cell with transfer substrate)
As shown in FIG. 5, the electrolyte membrane 14 with a catalyst layer for a fuel cell with a transfer substrate according to the fifth embodiment of the present invention has a transfer substrate 7 and a catalyst layer disposed on the transfer substrate 7. 2, an electrolyte membrane 1 containing a metal phosphate disposed on the catalyst layer 2, and a sealing layer 6 covering at least the end face of the catalyst layer 2 and the end face of the electrolyte membrane 1. The sealing layer 6 contains at least one of a metal phosphate and a binder.

  In the electrolyte membrane 14 with a catalyst layer for a fuel cell with a transfer substrate according to the present embodiment, the gas diffusion layer 4 of the electrolyte membrane 11 with a catalyst layer for a fuel cell in the second embodiment is replaced with a transfer substrate 7. Since other than that is the same as that of the second embodiment, a duplicate description is omitted.

  As the transfer substrate 7, the same transfer substrate as described in the fourth embodiment may be used.

  The electrolyte membrane 14 with a catalyst layer for a fuel cell with a transfer substrate according to the present embodiment is replaced with the gas diffusion layer 4 of the electrolyte membrane 11 with a catalyst layer for a fuel cell in the second embodiment, and the transfer substrate 7. Can be used to manufacture in the same manner as shown in the second embodiment.

  According to the present embodiment, since the sealing layer 6 covers the end face of the electrolyte membrane 1 and the end face of the catalyst layer 2, the reproducibility is excellent, the moldability is good, and there is no self-supporting membrane property. Electrolyte with a catalyst layer for a fuel cell with a transfer substrate that can be produced, and can produce an electrolyte membrane with a catalyst layer for a fuel cell that suppresses seepage of phosphoric acid and has high proton conductivity in a non-humidified state. A membrane 14 can be provided.

[Sixth embodiment]
(Electrolyte membrane with catalyst layer for fuel cell with transfer substrate)
As shown in FIG. 6, an electrolyte membrane 15 with a catalyst layer for a fuel cell with a transfer substrate according to a sixth embodiment of the present invention includes a transfer substrate 7 and a catalyst layer disposed on the transfer substrate 7. 2, an electrolyte membrane 1 containing a metal phosphate disposed on the catalyst layer 2, a catalyst layer 3 disposed on the surface of the electrolyte membrane 1 opposite to the transfer substrate 7 side, and at least a catalyst layer 2 3 and a sealing layer 6 covering the end face of each electrolyte membrane 1 and the end face of the electrolyte membrane 1. The sealing layer 6 contains at least one of a metal phosphate and a binder.

  The electrolyte membrane 15 with a catalyst layer for a fuel cell with a transfer substrate according to the present embodiment, except that the gas diffusion layer 4 of the electrolyte membrane 12 with a catalyst layer in the third embodiment is replaced with a transfer substrate 7. Since it is the same as that of 3rd Embodiment, the overlapping description is abbreviate | omitted.

  As the transfer substrate 7, the same transfer substrate as described in the fourth embodiment may be used.

  The electrolyte membrane 15 with a catalyst layer for a fuel cell with a transfer substrate according to the present embodiment uses a transfer substrate 7 instead of the gas diffusion layer 4 of the electrolyte membrane with a catalyst layer 12 in the third embodiment. Thus, it can be manufactured by the same method as shown in the third embodiment.

  According to the present embodiment, since the sealing layer 6 covers the end face of the electrolyte membrane 1 and the end faces of the catalyst layers 2 and 3, the reproducibility is excellent, the moldability is good, and there is no self-standing film property. The catalyst layer for a fuel cell with a transfer substrate can be produced, and can suppress the seepage of phosphoric acid and can produce an electrolyte membrane with a catalyst layer for a fuel cell that has high proton conductivity in a non-humidified state. The attached electrolyte membrane 15 can be provided.

[Seventh embodiment]
(Manufacturing method of fuel cell membrane / electrode assembly)
As shown in FIG. 8, the fuel cell membrane / electrode assembly manufacturing method according to the seventh embodiment of the present invention uses a fuel cell catalyst layer-attached electrolyte membrane 11 similar to that of the second embodiment. A process of joining two sheets with the electrolyte membrane 1 side facing each other is provided.

  According to this embodiment, two electrolyte membranes 11 with a fuel cell catalyst layer 11 are disposed with the electrolyte membrane 1 facing each other, and subjected to a hot press treatment such as hot pressing, whereby a membrane / electrode for a fuel cell The joined body 10 can be manufactured. Various presses can be used for this hot press process.

  Although the pressurization level at the time of hot pressing is not limited, for example, it is usually about 0.5 to 10 MPa, preferably about 1 to 10 MPa.

  Although the heating temperature at the time of hot pressing is not limited, for example, it is usually about 30 to 200 ° C., preferably about 50 to 170 ° C.

  Moreover, although press time is suitably determined according to heating temperature, For example, about 10-240 seconds normally, Preferably, what is necessary is just about 30-150 seconds.

  In addition, using the electrolyte membrane 14 with a catalyst layer for a fuel cell with a transfer substrate shown in the fifth embodiment, two electrolyte membranes 14 with a catalyst layer for a fuel cell with a transfer substrate are mutually attached to the electrolyte membrane 1 side. Are opposed to each other and subjected to a heat press treatment such as hot press to perform pressure bonding, and then the transfer substrates 7 and 7 on both sides are peeled off. Next, the fuel cell membrane / electrode assembly 10 is formed by pressure bonding the gas diffusion layers 4 and 5 to the catalyst layers 2 and 3 side by hot pressing such as hot pressing instead of the separated transfer base materials 7 and 7. Can be manufactured.

  The hot press treatment may be performed under the same conditions as described above for the pressure level, heating temperature, pressing time, and the like.

  According to the present embodiment, two electrolyte membranes 11 with fuel cell catalyst layers 11 are joined by pressure bonding with the electrolyte membrane 1 facing each other, so that it has excellent reproducibility, good moldability, and self-supporting A membrane / electrode assembly for a fuel cell that can be produced without having membrane properties, suppresses seepage of phosphoric acid, and has high proton conductivity in a non-humidified state can be efficiently produced.

[Eighth embodiment]
(Manufacturing method of fuel cell membrane / electrode assembly)
As shown in FIG. 9, the manufacturing method of the fuel cell membrane / electrode assembly according to the eighth embodiment of the present invention is similar to the fuel cell catalyst layer-attached electrolyte membrane 12 of the third embodiment. A step of forming the gas diffusion layer 5 on the surface side where the catalyst layer 3 is exposed is provided.

  The gas diffusion layer 5 can be joined to the fuel cell-attached electrolyte membrane 12 for a fuel cell by performing a hot press treatment such as hot press.

  Although the pressurization level at the time of hot pressing is not limited, for example, it is usually about 0.5 to 10 MPa, preferably about 1 to 10 MPa.

  Although the heating temperature at the time of hot pressing is not limited, for example, it is usually about 30 to 200 ° C., preferably about 50 to 170 ° C.

  Moreover, although press time is suitably determined according to heating temperature, For example, about 10-240 seconds normally, Preferably, what is necessary is just about 30-150 seconds.

  Moreover, after peeling off the transfer substrate 7 of the electrolyte membrane 15 with a catalyst layer for a fuel cell with a transfer substrate, using the electrolyte membrane 15 with a catalyst layer for a fuel cell with a transfer substrate shown in the sixth embodiment The fuel cell membrane / electrode assembly 10 can be manufactured by bonding the gas diffusion layers 4 and 5 to both surfaces thereof by hot pressing such as hot pressing and bonding them by pressure bonding.

  What is necessary is just to perform a heat press process on the conditions similar to the pressurization level mentioned above, heating temperature, and press time.

  According to the present embodiment, the gas diffusion layer 5 is joined to the electrolyte membrane 12 with a catalyst layer for a fuel cell by pressure bonding, so that it is excellent in reproducibility, has good moldability, and has no self-supporting membrane property. It is possible to efficiently produce a membrane / electrode assembly for a fuel cell that suppresses the seepage of phosphoric acid and has high proton conductivity in a non-humidified state.

[Ninth embodiment]
(Fuel cell)
As shown in FIG. 10, a fuel cell 20 according to a ninth embodiment of the present invention includes a membrane / electrode assembly 10 similar to that shown in FIG. 1 shown in the first embodiment, a pair of separators 21, 22. The membrane / electrode assembly 10 is sandwiched between separators 21 and 22. The other configuration is the same as that of the first embodiment, and a duplicate description is omitted.

(Separator)
The separator 22 is for supplying an oxidant gas to the gas diffusion layer 5 and has an oxidant gas flow path 24 for circulating the oxidant gas. On the other hand, the separator 21 is for supplying fuel to the gas diffusion layer 4 and has a fuel flow path 23 for circulating the fuel.

  The separators 21 and 22 may be made of any material having stable conductivity even in the environment inside the fuel cell 20. In general, a carbon plate having a flow path is used. The separators 21 and 22 are made of a metal such as stainless steel, and a coating made of a conductive material such as chromium, a platinum group metal or oxide thereof, or a conductive polymer is formed on the surface of the metal. Also good.

  The separators 21 and 22 can have a function as a current collector when used in a fuel cell in which a plurality of fuel cells 20 are stacked.

(Operating principle)
Hydrogen can be supplied fuel such as hydrogen gas or methanol to the fuel passage 23 is supplied to the anode catalyst layer 2 through the anode side gas diffusion layer 4, electrons from the fuel and protons (H ⁺⁾ (e ^-) Is generated. The generated protons are transported to the cathode side catalyst layer 3 side by the proton conductive electrolyte membrane 1. On the other hand, an oxidant gas such as air or oxygen gas is supplied to the cathode side catalyst layer 3 through the cathode side gas diffusion layer 5 in the oxidant gas flow path 24, and the proton that has been conveyed by the proton conductive electrolyte membrane 1. Reacts with the electrons coming from the external circuit 25 and the oxidizing gas to produce water. In this way, it functions as a fuel cell.

  The manufacturing method of the fuel cell 20 according to the present embodiment is different from the manufacturing method according to the first embodiment in that the method of forming the separators 21 and 22 on the membrane-electrode assembly 10 is different from the first manufacturing method. Since it is the same as that of embodiment, the overlapping description is abbreviate | omitted.

  In the method of manufacturing the fuel cell 20 according to the present embodiment, the separator 22 in which the oxidant gas flow path 24 is formed is disposed so that the oxidant gas flow path 24 is in contact with the cathode side gas diffusion layer 5 side. The fuel cell 20 shown in FIG. 10 can be manufactured by disposing the separator 21 formed with the passage 23 so that the fuel passage 23 is in contact with the anode gas diffusion layer 4 side.

  According to the present embodiment, it is excellent in reproducibility, has good moldability, can be produced without self-supporting film property, suppresses leaching of phosphoric acid, and has high proton conductivity in a non-humidified state. Since the membrane / electrode assembly for a fuel cell is used, the fuel cell 20 having excellent stability and high performance can be provided.

  Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited to these examples, and various modifications can be made without departing from the scope of the present invention.

[Example 1]
First, a metal phosphate was prepared as follows. Tin oxide (SnO ₂ : manufactured by Nano Tec) 13.56 g (0.09 mol) and indium oxide (In ₂ O ₃ : manufactured by Nacalai Tesque) 1.40 g (0.0050 mol) of diammonium hydrogen phosphate ( 27.99 g (0.212 mol) (Nacalai Tesque) was added and mixed with a spoon.

The obtained mixture was put into a crucible, baked at about 650 ° C. for about 2 hours, and the product obtained after sintering was pulverized with an agate nail to obtain metal phosphate Sn _0.9 In _0.1 P ₂ O ₇ . Obtained.

  1 g of the metal phosphate obtained above, 16 g of cellulose acetate as a binder and 3 g of a solvent (water / alcohol = 1/1 mixed solution) were mixed and mixed by a disperser for about 24 hours to prepare a sealing layer paste. . Next, in the center of the gas diffusion layer 4 (10 cm × 10 cm, SGL35BC, manufactured by SGL Carbon Co., Ltd.), the sealing layer paste is a square having an outer frame length and width of 5 cm × 5 cm and a frame width of 0.5 cm. The frame was coated by screen printing and dried at about 95 ° C. for about 20 minutes. Thereby, the sealing layer 6 having a thickness of 80 μm was formed on the gas diffusion layer 4.

  Next, 1.8 g of 85% phosphoric acid aqueous solution was added to 10 g of the metal phosphate, and these were mixed with a spoon. The obtained mixture was put into a crucible, fired at about 160 ° C. for about 30 minutes, and the product obtained after sintering was pulverized in an agate bowl to obtain a fired product of metal phosphate and liquid phosphoric acid.

  Next, 5 g of the fired product of the above metal phosphate and liquid phosphoric acid, 10 g of platinum-supported carbon (TEC10E50E, Tanaka Kikinzoku Co., Ltd.), 4 g of binder (cellulose acetate), 3 g of solvent (water / alcohol = 1/1 mixed solution) And mixed for about 24 hours with a disperser to prepare a catalyst paste.

Next, the catalyst paste is applied in a frame of the sealing layer 6 on the gas diffusion layer 4 on which the sealing layer 6 is formed so that the amount of platinum supported is about 0.5 mg / cm ^2. Dry at 20 ° C. for about 20 minutes. As a result, a catalyst layer 2 having a thickness of 30 μm was formed, and a gas diffusion layer with a catalyst layer was produced.

  Next, 4 g of binder (cellulose acetate) and 3 g of solvent (water / alcohol = 1/1 mixed solution) are mixed with 5 g of the fired product of metal phosphate and liquid phosphoric acid, and dispersed by a disperser for about 24 hours. A paste was prepared.

  Next, the electrolyte membrane paste is applied onto the catalyst layer 2 in the frame of the sealing layer 6 of the gas diffusion layer with the catalyst layer and dried at about 95 ° C. for about 20 minutes, and the thickness of the electrolyte membrane 1 is 50 μm. An electrolyte membrane 11 with a catalyst layer was produced.

  The obtained two electrolyte membranes with catalyst layer 11 are arranged so that the electrolyte membrane 1 faces each other, and hot pressed for 120 seconds under the conditions of a pressure level of 4 MPa and a heating temperature of 150 ° C. Obtained.

  Finally, the obtained membrane / electrode assembly 10 was assembled into a JARI standard cell. The JARI standard cell is developed by the Japan Automobile Research Institute (JARI) for basic research of PEFC and evaluation tests of PEFC materials (membranes, electrode catalysts, components, etc.). Cell.

[Example 2]
An electrolyte membrane 11 with a catalyst layer was prepared in the same manner as in Example 1 except that polycycloolefin (Zeonor 1600, manufactured by Nippon Zeon Co., Ltd.) was used as the binder for the sealing layer 6.

  The two electrolyte membranes 11 with the catalyst layer thus obtained were placed so that the electrolyte membrane 1 side was opposite to the membrane as in Example 1, and hot-pressed under the same conditions as in Example 1 to form the membrane / electrode assembly 10. Obtained. The membrane / electrode assembly 10 was assembled into a JARI standard cell.

[Example 3]
Electrolyte membrane with catalyst layer in the same manner as in Example 1 except that polycycloolefin (Zeonor 1600, manufactured by Nippon Zeon Co., Ltd.) was used as a binder for the sealing layer 6 and the sealing layer 6 having a thickness of 110 μm was formed. Was made.

Next, the catalyst paste was prepared in the same manner as in Example 1, the electrolyte membrane 1 platinum content on about 0.5 mg / cm ² in the framework of the sealing layer 6 of the resultant catalyst layer with the electrolyte membrane It was coated so as to be dried at about 95 ° C. for about 20 minutes. Thus, a catalyst layer 3 having a thickness of 30 μm was formed, and an electrolyte membrane 12 with a catalyst layer was produced.

  Next, a gas diffusion layer (10 cm × 10 cm, SGL35BC, manufactured by SGL Carbon Co.) was formed on the catalyst layer 3 and the sealing layer 6 to prepare a fuel cell membrane / electrode assembly 10. The membrane / electrode assembly 10 was assembled into a JARI standard cell.

[Example 4]
In the preparation of the sealing layer paste, instead of 1 g of metal phosphate and 16 g of cellulose acetate as a binder, 17 g of polycycloolefin (Zeonor 1600, manufactured by Nippon Zeon Co., Ltd.) as a binder is used without using metal phosphate, An electrolyte membrane with a catalyst layer was produced in the same manner as in Example 1 except that the sealing layer 6 having a thickness of 110 μm was formed.

Next, a catalyst paste produced in the same manner as in Example 1 was obtained with a platinum loading of about 0.5 mg / cm ² on the electrolyte membrane 1 in the frame of the sealing layer 6 of the obtained electrolyte membrane with catalyst layer. It was coated so as to be dried at about 95 ° C. for about 20 minutes. Thus, a catalyst layer 3 having a thickness of 30 μm was formed, and an electrolyte membrane 12 with a catalyst layer was produced.

  Next, a gas diffusion layer (10 cm × 10 cm, SGL35BC, manufactured by SGL Carbon Co.) was formed on the catalyst layer 3 and the sealing layer 6 to prepare a fuel cell membrane / electrode assembly 10. The membrane / electrode assembly 10 was assembled into a JARI standard cell.

[Example 5]
In the preparation of the sealing layer paste, instead of using 1 g of metal phosphate and 16 g of cellulose acetate as a binder, 17 g of cellulose acetate was used as a binder without using metal phosphate, and a sealing layer 6 having a thickness of 110 μm was formed. Produced a catalyst layer-attached electrolyte membrane in the same manner as in Example 1.

Next, a catalyst paste produced in the same manner as in Example 1 was used, and the amount of platinum supported on the electrolyte membrane 1 in the frame of the sealing layer 6 of the obtained electrolyte membrane with catalyst layer was about 0.5 mg / cm ² . It was coated so as to be dried at about 95 ° C. for about 20 minutes. Thus, a catalyst layer 3 having a thickness of 30 μm was formed, and an electrolyte membrane 12 with a catalyst layer was produced.

  Next, a gas diffusion layer (10 cm × 10 cm, SGL35BC, manufactured by SGL Carbon Co.) was formed on the catalyst layer 3 and the sealing layer 6 to prepare a fuel cell membrane / electrode assembly 10. The membrane / electrode assembly 10 was assembled into a JARI standard cell.

[Example 6]
A polycycloolefin (Zeonor 1600, manufactured by Nippon Zeon Co., Ltd.) is used as a binder for the sealing layer 6, and a transfer substrate 7 (PET) is used instead of the gas diffusion layer 4 to form a sealing layer 6 having a thickness of 110 μm. An electrolyte membrane with a catalyst layer (that is, an electrolyte membrane with a catalyst layer and a transfer substrate) was produced in the same manner as in Example 1 except that it was formed.

Next, a catalyst paste produced in the same manner as in Example 1 has a platinum loading amount of about 0.5 mg on the electrolyte membrane 1 in the frame of the sealing layer 6 of the obtained electrolyte membrane with a catalyst layer with a transfer substrate. / Cm ^2, and dried at about 95 ° C. for about 20 minutes. Thus, a catalyst layer 3 having a thickness of 30 μm was formed, and an electrolyte membrane 15 with a catalyst layer with a transfer substrate was produced.

  Next, the transfer base material 8 was formed on the catalyst layer 3 and the sealing layer 6 to produce an electrolyte membrane 13 with a catalyst layer for a fuel cell with a transfer base material.

  Next, the transfer substrates 7 and 8 are peeled off from the electrolyte membrane 13 with a catalyst layer for a fuel cell with a transfer substrate, and the gas diffusion layers 4 and 5 (10 cm × 10 cm, SGL35BC, manufactured by SGL Carbon Co.) are used as the catalyst layer 2. 3 and the sealing layer 6 to produce a fuel cell membrane / electrode assembly 10. The membrane / electrode assembly 10 was assembled into a JARI standard cell.

[Comparative Example 1]
1 g of the metal phosphate obtained in the same manner as in Example 1, 16 g of polycycloolefin (Zeonor 1600, manufactured by Nippon Zeon Co., Ltd.) as a binder, and 2 g of a solvent (water / alcohol = 1/1 mixed solution) are mixed and dispersed. A paste for a sealing layer was prepared by mixing for about 24 hours using a machine. Next, in the center of the gas diffusion layer 4 (10 cm × 10 cm, SGL35BC, manufactured by SGL Carbon Co., Ltd.), the sealing layer paste is a square having an outer frame length and width of 5 cm × 5 cm and a frame width of 0.5 cm. The frame was coated by screen printing and dried at about 95 ° C. for about 20 minutes. Thereby, the sealing layer 6 having a thickness of 30 μm was formed on the gas diffusion layer 4.

Next, the catalyst paste obtained in the same manner as in Example 1 has a platinum loading amount of about 0.5 mg / cm ² in the frame of the sealing layer 6 on the gas diffusion layer 4 on which the sealing layer 6 is formed. And dried at about 95 ° C. for about 20 minutes. As a result, a catalyst layer 2 having a thickness of 30 μm was formed, and a gas diffusion layer with a catalyst layer was produced.

  Next, the electrolyte membrane paste obtained in the same manner as in Example 1 was coated on the catalyst layer 2 in the frame of the sealing layer 6 except for the sealing layer 6 of the gas diffusion layer with catalyst layer. And it dried at about 95 degreeC and about 20 minutes, and produced electrolyte membrane 11A with a catalyst layer whose thickness of the electrolyte membrane 1 is 50 micrometers.

  Two obtained electrolyte membranes 11A with a catalyst layer were placed so that the electrolyte membrane 1 faces each other, and hot-pressed for 120 seconds under the conditions of a pressure level of 4 MPa and a heating temperature of 150 ° C. A membrane / electrode assembly in which the sealing layer 6 was formed only on the end faces of the layers 2 and 3 was obtained. This membrane / electrode assembly was assembled into a JARI standard cell.

(Measurement of electromotive force)
About each cell obtained in Examples 1-6 and Comparative Example 1, IV measurement was performed using 120 degreeC and non-humidified gas, and the electromotive force of each cell in 100 mA / cm < ² > was investigated. The results are shown in Table 1.

As shown in Table 1, Examples 1 to 6 within the scope of the present invention showed good electromotive force at 100 mA / cm ² . In contrast, Comparative Example 1 showed an extremely low electromotive force as compared with Examples 1-6.

(PH measurement)
About each cell obtained in Examples 1-6 and Comparative Example 1, when IV measurement was performed using 120 degreeC and non-humidified gas, pH was investigated in piping of cathode production | generation water. The results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 6 within the scope of the present invention, it can be seen that there is no leaching of phosphoric acid and the produced water is neutral. On the other hand, the comparative example 1 showed acidity compared with Examples 1-6, and the oozing out of phosphoric acid was recognized.

(Water repellency)
Regarding the water repellency of the sealing layer used in Examples 1 to 6 and Comparative Example 1, the binder used in the sealing layer was uniformly applied on the film, and after dropping a drop of water from the top, the contact angle of water It was investigated by measuring. The measured values are shown in parentheses. Evaluation of water repellency is ○ when the contact angle of the binder used for the sealing layer is equal to or larger than the contact angle of the binder used for the electrolyte membrane / catalyst layer, less than the contact angle of the binder used for the electrolyte membrane / catalyst layer When it was, it was set as x. The results are shown in Table 1.
The contact angle can be measured using a contact angle meter by the θ / 2 method, the tangent method, the curve fitting method, or the like.

  As shown in Table 1, in Examples 1 to 6 within the scope of the present invention, the contact angle of the binder used for the sealing layer is equal to or greater than the contact angle of the binder used for the electrolyte membrane / catalyst layer. Excellent water repellency. On the other hand, in Comparative Example 1, the water repellency of the binder was as good as in Examples 1-6. However, in Comparative Example 1, it is difficult to cope with the leaching of phosphoric acid from the electrolyte membrane because the sealing layer is provided only on the end face of the catalyst layer.

(Adhesion)
The adhesion between the sealing layer and the electrolyte membrane was examined as follows. That is, each electrolyte paste used in Examples 1 to 6 was coated on a Kapton film and dried at about 95 ° C. for about 20 minutes to form an electrolyte membrane having a thickness of 50 μm. On top of that, the sealing layer paste used in Examples 1 to 6 was applied and dried at about 95 ° C. for about 20 minutes to form a sealing layer. After sticking a commercially available cellophane tape on the surface of the sealing layer, the cellophane tape was peeled off to examine the adhesion between the electrolyte membrane and the sealing layer. The case where only the cellophane tape was peeled off was marked as “◯”, and the case where the cellophane tape was peeled off with the sealing layer adhered was marked as “x”. The results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 6 within the scope of the present invention, peeling of the sealing layer was not confirmed, and it was found that the adhesion between the sealing layer and the electrolyte membrane was good.

  From the above, the membrane / electrode assembly for a fuel cell according to the present invention has excellent reproducibility, good moldability, prevents oozing out of phosphoric acid, and has high proton conductivity in a non-humidified state. I understood.

DESCRIPTION OF SYMBOLS 1 ... Electrolyte membrane 2 ... Fuel cell catalyst layer (anode side)
3. Fuel cell catalyst layer (cathode side)
4 ... Gas diffusion layer (anode side)
5 ... Gas diffusion layer (cathode side)
6 ... Sealing layers 7, 8 ... Transfer base material 10 ... Fuel cell membrane / electrode assembly 11, 11A, 12 ... Fuel cell catalyst membrane-attached electrolyte membranes 13, 14, 15, ..Electrolyte membrane with catalyst layer 20 for fuel cell with transfer substrate ... Fuel cell 21 ... Separator (anode side)
22 ... Separator (cathode side)
23 ... Fuel channel 24 ... Oxidant gas channel 25 ... External circuit

Claims (13)

An electrolyte membrane containing a metal phosphate;
A catalyst layer arranged to sandwich the electrolyte membrane;
A substrate disposed on the surface of each of the catalyst layers opposite to the surface in contact with the electrolyte membrane;
A sealing layer covering at least an end face of the electrolyte membrane and an end face of each of the catalyst layers, and the sealing layer includes at least one of a metal phosphate and a binder. An electrolyte membrane with a catalyst layer for a fuel cell. A substrate;
A catalyst layer disposed on the substrate;
An electrolyte membrane comprising a metal phosphate disposed on the catalyst layer;
And a sealing layer covering end faces of the catalyst layer and the electrolyte membrane, wherein the sealing layer contains at least one of a metal phosphate and a binder. Electrolyte membrane with catalyst layer. A substrate;
A catalyst layer disposed on the substrate;
An electrolyte membrane comprising a metal phosphate disposed on the catalyst layer;
A catalyst layer disposed on a surface opposite to the substrate side of the electrolyte membrane;
At least an end face of each of the catalyst layers and an end face covering the end face of the electrolyte membrane, wherein the end stop layer includes at least one of metal phosphate and binder. An electrolyte membrane with a catalyst layer for a fuel cell.   The said base material is a gas diffusion layer, The electrolyte membrane with a catalyst layer for fuel cells of any one of Claims 1-3 characterized by the above-mentioned.   The electrolyte membrane with a catalyst layer for a fuel cell according to any one of claims 1 to 3, wherein the substrate is a transfer substrate.   The electrolyte membrane with a catalyst layer for a fuel cell according to claim 1, wherein the sealing layer contains a metal phosphate.   The electrolyte membrane with a catalyst layer for a fuel cell according to any one of claims 1 to 6, wherein the sealing layer, the electrolyte membrane, and the catalyst layer contain the same type of binder.   The electrolyte membrane and the catalyst layer contain a different type of binder from the binder used for the sealing layer, and at least one binder used for the electrolyte membrane and the catalyst layer has a glass transition point or a softening point. The electrolyte membrane with a catalyst layer for a fuel cell according to any one of claims 1 to 6, wherein the electrolyte membrane has a difference of 50 ° C or less from the binder used for the stopper layer.   The electrolyte membrane with a catalyst layer for a fuel cell according to claim 8, wherein the binder used for the sealing layer is one selected from a cycloolefin polymer, polyamideimide, and polyimide. Preparing a gas diffusion layer;
Forming a sealing layer in a frame shape on the gas diffusion layer;
Forming a catalyst layer on the surface of the gas diffusion layer surrounded by the sealing layer;
Forming an electrolyte membrane on the catalyst layer;
Forming the catalyst layer on the electrolyte membrane;
And a step of forming the gas diffusion layer on the electrolyte membrane and the sealing layer. A method for producing a membrane / electrode assembly for a fuel cell, comprising:   A method for producing a membrane / electrode assembly for a fuel cell, comprising the step of joining two of the electrolyte membranes with a catalyst layer for a fuel cell according to claim 2 with the electrolyte membrane facing each other.   A fuel cell membrane / electrode assembly comprising a step of forming a gas diffusion layer on the surface of the electrolyte membrane with a catalyst layer for a fuel cell according to claim 3 where the catalyst layer is exposed. Production method. A membrane / electrode assembly for a fuel cell produced by the method for producing a membrane / electrode assembly for a fuel cell according to any one of claims 10 to 12,
A fuel cell comprising a pair of separators, wherein the membrane-electrode assembly for a fuel cell is sandwiched between the separators.

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