JP2012064343A - Catalyst layer-electrolyte membrane stack, membrane-electrode junction body and fuel cell using the stack, and manufacturing method of the stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst layer-electrolyte membrane stack which is excellent in mechanical strength despite a thin electrolyte membrane, in which adhesion between catalyst layer and electrolyte membrane is improved, and has high proton conductivity under a non-humidified state, and a membrane-electrode junction body and a fuel cell using the stack, and a manufacturing method of the stack.SOLUTION: A catalyst layer-electrolyte membrane stack of the present invention includes an electrolyte membrane 1 and catalyst layers 2a, 2b, the electrolyte membrane 1 includes solid acid and a porous support body 3, the catalyst layers 2a, 2b include a catalyst and are respectively joined to the both surfaces of the electrolyte membrane 1, and the porous support body 3 penetrates the electrolyte membrane 1 and at least a part of one or both of the catalyst layers 2a, 2b. A manufacturing method of the present invention includes a process of forming a catalyst layer including a porous support body at least in a part thereof, a process of forming an electrolyte membrane including the porous support body, and a process of forming another catalyst layer that includes or does not include the porous support body at least in a part thereof.

Description

  The present invention relates to a catalyst layer-electrolyte membrane laminate, a membrane electrode assembly and a fuel cell using the same, and a method for producing 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. Among them, the development of a polymer electrolyte fuel cell (PEFC) 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 is expected.

A polymer electrolyte fuel cell is basically composed of a membrane electrode assembly in which electrodes are bonded to both surfaces of an electrolyte membrane usually made of a solid polymer electrolyte. As the solid polymer electrolyte, perfluorosulfonic acid or the like generally known as Nafion (registered trademark) is used, but transporting protons in a state where the proton conduction mechanism is H ₃ O ⁺ (Vehicle) ) Mechanism, it is necessary to provide a humidifying mechanism, which causes a problem that the system becomes complicated.

  Therefore, metal phosphates have been proposed as proton conductive electrolytes having proton conductivity in a non-humidified state (see, for example, Patent Document 1). Moreover, what doped another kind of metal to some metal phosphates is proposed (for example, refer patent document 2, 3).

  However, since the metal phosphates proposed in Patent Documents 1 to 3 are powders, formability is difficult, and usually a film is formed by adding a binder. In order to inhibit proton conductivity, there is a trade-off relationship between proton conductivity and mechanical performance of the electrolyte membrane, and there is a problem that it is difficult to achieve both proton conductivity and membrane strength of the electrolyte membrane.

  On the other hand, a composite membrane in which a porous material is impregnated with an electrolyte has been proposed as an electrolyte membrane with improved membrane strength and improved mechanical performance (see, for example, Patent Documents 4 to 6).

And, from the viewpoint of improving the output characteristics of the fuel cell, it is recommended to make the electrolyte membrane thinner,
When a composite film in which a porous material is impregnated with an electrolyte is made into a thin film, there is a problem that sufficient film strength cannot be obtained.

  Furthermore, from the viewpoint of improving the battery performance of the fuel cell, it is required to improve the bonding property between the electrolyte membrane and the catalyst layer (for example, Patent Document 7).

JP 2005-294245 A JP 2008-53224 A JP 2008-53225 A JP 2002-8680 A Japanese National Patent Publication No. 11-501964 JP-A-10-92444 JP 2008-293737 A

  In order to solve the above-described conventional problems, the present invention is a catalyst layer that is excellent in mechanical strength while the electrolyte membrane is a thin film, has improved adhesion between the catalyst layer and the electrolyte membrane, and has high proton conductivity in a non-humidified state. An electrolyte membrane laminate, a membrane electrode assembly and a fuel cell using the same, and a method for producing the same are provided.

  The catalyst layer-electrolyte membrane laminate of the present invention is a catalyst layer-electrolyte membrane laminate comprising an electrolyte membrane and a pair of catalyst layers, the electrolyte membrane comprising a solid acid and comprising a porous support. The catalyst layer includes a catalyst and is bonded to both surfaces of the electrolyte membrane, and the porous support penetrates at least part of one or both of the electrolyte membrane and the catalyst layer. It is characterized by being.

  The membrane electrode assembly of the present invention comprises the catalyst layer-electrolyte membrane laminate of the present invention and a pair of gas diffusion layers, and the gas diffusion layers are disposed on both sides of the catalyst layer-electrolyte membrane laminate, respectively. It is characterized by being.

  The fuel cell of the present invention includes the catalyst layer-electrolyte membrane laminate of the present invention, a pair of gas diffusion layers, and a pair of separators, and the gas diffusion layer and the separator are the catalyst layer-electrolyte membrane laminates. It is characterized by being sequentially laminated on both sides of the body.

  Further, the method for producing a proton conductive electrolyte membrane of the present invention includes a step of forming a catalyst layer including a catalyst and having a porous support at least partially, and an electrolyte membrane including a solid acid and including the porous support. And a step of forming the other catalyst layer containing a catalyst and having a porous support at least partially or not having a porous support, wherein the porous support is the electrolyte. It is characterized by penetrating a part of the catalyst layer of at least one or both of the membrane.

  According to the present invention, the porous support penetrates at least part of one or both of the electrolyte membrane and the catalyst layer, so that the electrolyte membrane is excellent in mechanical strength while being a thin film. A catalyst layer-electrolyte membrane laminate having improved adhesion and high proton conductivity in a non-humidified state, and a membrane electrode assembly and a fuel cell using the same can be provided. Further, according to the production method of the present invention, the catalyst layer is excellent in mechanical strength while the electrolyte membrane is thin, the adhesion between the catalyst layer and the electrolyte membrane is improved, and the catalyst layer-electrolyte having high proton conductivity in a non-humidified state A film laminate is easily obtained.

1A to 1E are schematic cross-sectional views showing some examples of a catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. FIG. 2A is a schematic cross-sectional view showing an example of the manufacturing process of the catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. FIG. 2B is a schematic cross-sectional view showing another example manufacturing process of the catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. FIG. 2C is a schematic cross-sectional view showing another example manufacturing process of the catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. FIG. 2D is a schematic cross-sectional view showing another example manufacturing process of the catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. FIG. 2E is a schematic cross-sectional view showing another example manufacturing process of the catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of a membrane electrode assembly according to Embodiment 2 of the present invention. FIG. 4 is a schematic cross-sectional view showing an example of a fuel cell according to Embodiment 3 of the present invention. FIG. 5 is an SEM photograph of 250 times magnification of the electrolyte used in one example of the present invention. FIG. 6 is an SEM photograph at a magnification of 30,000 times of the electrolyte in the electrolyte membrane in one example of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following embodiments exemplify materials and manufacturing methods for embodying the technical idea of the present invention, and the technical idea of the present invention is limited to the following materials and manufacturing methods. It is not what you do. The technical idea of the present invention can be variously modified within the scope of the claims.

[Embodiment 1]
First, a catalyst layer-electrolyte membrane laminate will be described as Embodiment 1 of the present invention.

(Catalyst layer-electrolyte membrane laminate)
1A to 1E are schematic cross-sectional views showing some examples of a catalyst layer-electrolyte membrane laminate according to Embodiment 1 of the present invention. 1A to 1E, the catalyst layer-electrolyte membrane laminate 10 includes an electrolyte membrane 1 and a pair of catalyst layers 2a and 2b, and the electrolyte membrane 1 includes a porous support 3. The catalyst layers 2a and 2b are respectively joined to both surfaces of the electrolyte membrane 1, and the porous support 3 penetrates the electrolyte membrane 1 and at least part of one or both of the catalyst layers 2a and 2b. The electrolyte membrane 1 contains a solid acid, and the catalyst layer contains a catalyst.

[Electrolyte membrane]
The thickness of the electrolyte membrane 1 is not particularly limited, and is usually about 20 to 1000 μm, preferably about 20 to 300 μm from the viewpoint of strength, and preferably 20 to 50 μm from the viewpoint of a thin film.

<Solid acid>
In the present invention, the “solid acid” means a solid that exhibits acid characteristics. The solid acid is not particularly limited. For example, an inorganic solid acid or an organic solid acid can be used. From the viewpoint of proton conductivity, proton conductivity can be obtained in a temperature range from room temperature to 200 ° C. and in a non-humidified atmosphere. It is preferable to use a solid acid. In this specification, the non-humidified atmosphere means that intentional humidification is not performed in the atmosphere where the solid acid is placed. Moreover, room temperature means that intentional temperature adjustment is not performed in the atmosphere in which the solid acid is placed for the purpose of the present invention.

  The organic solid acid is not particularly limited as long as it is an organic acid having a sulfonic acid group. For example, benzenesulfonic acid, dodecylbenzenesulfonic acid, 2-naphthalenesulfonic acid, 1,5-naphthalenedisulfonic acid, 2,6-naphthalenedisulfonic acid, 1,3,6-naphthalenetrisulfonic acid, 1,3,5, Examples include 7-naphthalene tetrasulfonic acid. You may use the organic acid which has the said sulfonic acid group individually or in mixture of 1 or more types.

  As the inorganic solid acid, for example, an inorganic solid acid having proton conductivity can be used, and an inorganic salt having proton conductivity is preferable.

Examples of the inorganic salt having proton conductivity include metal phosphates and metal sulfates. Examples of the metal phosphate include compounds such as orthophosphate and pyrophosphate. Among these, from the viewpoint of proton conductivity, a metal phosphate represented by the following formula (1) is more preferable.
M _1-x N _x P ₂ O ₇ (1)
However, in Formula (1), X is 0 ≦ X <0.5, and M is a group consisting of Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na, and Al. N is one selected from the group consisting of Al, In, B, Ga, Sc, Yb, Ce, La, Sb, Y, Nb and Mg.

  Specific examples of the metal phosphate include tin phosphate, zirconium phosphate, cesium phosphate, and tungsten phosphate. Pyrophosphate is preferred 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.

  The metal phosphate may be doped with a metal different from the main metal using a metal such as Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na or Al as the main metal. Good. When a doped metal is used, it is preferable to use Sn, Cs, Ti, or 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 dope metal varies depending on the solid solubility limit. When Sn is used as the main metal and In is used as the dope metal, for example, the molar ratio is Sn / In = 7/3 to 9.8 / 0.2. A range of is desirable.

  The metal phosphate can be synthesized, for example, by heating one or more metal oxides and phosphoric acid, followed by heat treatment.

  The metal oxide is not particularly limited as long as it can generate phosphoric acid and a crystalline salt. Examples thereof include oxides made of metal elements such as Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na, and Al.

  Specifically, the metal phosphate can be produced as follows. First, a compound containing a main metal such as tin (hereinafter also simply referred to as a main metal compound), a compound containing a doping metal such as indium (hereinafter also simply referred to as a doping metal compound), liquid phosphoric acid, Blend in moles to obtain a mixture. Next, water is added to the obtained mixture, and the mixture is stirred and dispersed with a stirrer or the like at a temperature of about 100 to 300 ° C. for about 1 to 3 hours to obtain a dispersion. The obtained dispersion is put in a crucible and baked at a temperature of about 300 to 700 ° C. for about 1 to 3 hours, for example. Since phosphoric acid may be lost in the high temperature state, it is desirable to add a large number of moles of liquid phosphoric acid, for example, about 1.1 to 1.5 times the molar equivalent. As the main metal compound and the doping metal compound, for example, a metal oxide, a metal hydroxide, a metal chloride, or a metal nitrate can be used.

  In the above, in order to avoid the problem of disappearance of phosphoric acid during firing, solid phosphoric acid may be used instead of liquid phosphoric acid. As the solid phosphoric acid, for example, a metal oxide containing a main metal such as tin and a metal oxide containing a doping metal such as indium using a monoammonium phosphate, an ammonium dihydrogen phosphate, etc. Mix in moles. The metal oxide containing the main metal and the metal oxide containing the doping metal are preferably mixed at a molar ratio of the main metal to the doping metal of, for example, about 9/1 to 1/1. The obtained mixture is 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.

Moreover, the said metal phosphate can also be produced by a coprecipitation method. For example, tin chloride pentahydrate (SnCl ₄ .5H ₂ O) and indium chloride tetrahydrate (InCl ₃ .4H ₂ O) are added at a predetermined concentration so that the molar ratio of tin to indium is about 9/1. After adjusting to an aqueous solution, while stirring with a stirrer, an aqueous ammonia solution is added dropwise until the pH becomes 7, whereby a small amount of indium hydroxide (In (OH) ₃ ) is uniformly contained in tin hydroxide (Sn (OH) ₄ ). A precipitate in the state present in is obtained. Thereafter, the precipitate is suctioned, filtered and dried, the above-mentioned hydroxide salt and phosphoric acid are mixed, and heat treatment is carried out in a reducing atmosphere at about 200 ° C. for about 2 hours to obtain a metal phosphate. . Finally, wash with deionized water. According to the coprecipitation method, a powder in which indium is uniformly doped with tin phosphate can be prepared by simultaneously precipitating a plurality of types of hardly soluble salts from a solution containing a plurality of desired metal ions.

  The solid acid may be an electrolyte composed of the metal phosphate and phosphoric acid.

  The phosphoric acids (hereinafter also simply referred to as “phosphoric acid”) refer to orthophosphoric acid and phosphoric acid condensate, and examples of the phosphoric acid condensate include pyrophosphoric acid, triphosphoric acid, metaphosphoric acid (polyphosphoric acid), and the like. It is done.

In addition, the electrolyte composed of the above-described metal phosphate and phosphoric acid has the number of atoms of the metal element of the metal phosphate and the metal element to be doped [m] and [n], respectively, and the phosphorus of the metal phosphate. When the sum of the number of atoms and the number of phosphorus atoms in phosphoric acid is [p], it is preferable to satisfy the following formula (2).
2 <[p] / ([m] + [n]) ≦ 4 (2)

More preferably, the following formula (3) is satisfied.
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. When the value of the above formula [p] / ([m] + [n]) is 2 or less, the amount of phosphoric acid on the metal phosphate is reduced, and the proton conductivity is hardly improved. On the other hand, if the value of the above formula [p] / ([m] + [n]) exceeds 4, the amount cannot be maintained because the amount of phosphoric acid is too high and moisture in the atmosphere is so high that the molded body becomes brittle. There is a fear.

Further, as the inorganic salt having proton conductivity, a complex of a heteropolyacid and an inorganic salt may be used. Examples of the inorganic salt include hydrogen sulfate and hydrogen phosphate. Examples of the hydrogen sulfate include cesium hydrogen sulfate and potassium hydrogen sulfate. Examples of the hydrogen phosphate include cesium hydrogen phosphate. Examples of the heteropolyacid include phosphotungstic acid (H ₃ PW ₁₂ O ₄₀ : WPA). Further, cesium carbonate (Cs ₂ CO ₃ ), cesium sulfate (Cs ₂ SO ₄ ), or the like may be used instead of hydrogen sulfate or hydrogen phosphate. Among these, from the viewpoint of proton conductivity, a complex of hydrogen sulfate and heteropolyacid is preferable, and a complex of potassium hydrogen sulfate and phosphotungstic acid obtained by a mechanochemical method is more preferable.

A complex of tungsten phosphoric acid and potassium hydrogen sulfate (KHSO ₄ ), which is a kind of a complex of a heteropolyacid and an inorganic salt, can be produced by, for example, the following mechanochemical method. WPA (H ₃ PW ₁₂ O ₄₀ : 12 Tungsto (VI) phosphoric acid n hydrate) is preliminarily dried at a temperature of 60 ° C. for about 5 to 24 hours to obtain hexahydrate (WPA · 6H ₂ O). . Next, the obtained WPA · 6H ₂ O, potassium hydrogen sulfate (KHSO ₄ ) and the ball are put in an agate pot. Then, the complex of tungsten phosphoric acid and potassium hydrogen sulfate (KHSO ₄ ) is obtained by mixing at 720 rpm for 10 minutes with a planetary ball mill (manufactured by Frichce Japan KK, P-7). It is preferable that the compounding quantity of tungsten phosphoric acid and potassium hydrogen sulfate is 1 / 99-40 / 60 by molar ratio, for example.

  In the mechanochemical method, a composite of tungsten phosphate and potassium hydrogen sulfate is synthesized by utilizing a large mechanical energy such as impact and friction obtained by milling using a ball mill or the like. Therefore, when producing a composite of tungsten phosphate and potassium hydrogen sulfate, there is an advantage that production is relatively easy because a high-temperature process is not required unlike metal phosphates.

It is thought that the above-mentioned milling treatment is related to the improvement of conductivity by the formation of hydrogen bonds in the form of Bronsted acid-base pairs between the KPA Keggin anion PW ₁₂ O ₄₀ ³⁻ and the HSO ₄ ⁻ anion of KHSO _4. It is done. Combining hydrogen sulfate and heteropoly acid by mechanochemical method, introducing defect structures and random structures at high density on the surface of inorganic solids, and designing a hydrogen bond network is a composite with high proton conductivity in a wide temperature range It is an important guide for synthesizing the body.

Further, as the solid acid, a complex of cesium phosphoric acid and silicon phosphate (SiP ₂ O ₇ ) may be used. Examples of the cesium phosphoric acid include cesium dihydrogen phosphate (CsH ₂ PO ₄ ), cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ), and the like.

Complex of cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) or cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ) and silicon phosphate (SiP ₂ O ₇ ) For example, the composite is prepared as follows.

First, cesium dihydrogen phosphate (CsH ₂ PO ₄ ) or cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ) is prepared as follows. Cesium carbonate (Cs ₂ CO ₃ ) and water are mixed at a predetermined ratio and stirred with a stirrer using a stirrer or the like. Next, a predetermined number of moles of liquid phosphoric acid are added dropwise little by little, and water is evaporated while stirring at a temperature of about 100 to 150 ° C. for about 1 to 3 hours. Then, it puts into oven and dries at the temperature of about 100-150 degreeC, for example. The drying time is, for example, about 1 day to several days. Next, the product obtained by drying is pulverized in an agate bowl to form a powder, and the desired cesium dihydrogen phosphate (CsH ₂ PO ₄ ) or cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ) is obtained. Obtainable.

Next, silicon phosphate (SiP ₂ O ₇ ) is produced as follows. Silicon dioxide (SiO ₂ ) and liquid phosphoric acid are blended in a predetermined number of moles. The mixture is then placed in an agate noodle and mixed until it is in a candy form. Then, it puts into an alumina crucible and fires at a temperature of about 100 to 700 ° C. The firing time is, for example, about 30 to 80 hours. Next, the product obtained by firing can be pulverized in an agate bowl to obtain the desired silicon phosphate (SiP ₂ O ₇ ).

Next, cesium dihydrogen phosphate (CsH ₂ PO ₄ ) or cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ) and silicon phosphate (SiP ₂ O ₇ ) are blended in a predetermined number of moles. The obtained mixture was dispersed with a pod mill or the like, and a composite of cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) or cesium dihydrogen phosphate (CsH ₅ (PO ₄ )). ₂ ) A composite of silicon phosphate (SiP ₂ O ₇ ) is obtained. The dispersion time is, for example, about 1 hour to 30 hours. The blending amount of cesium dihydrogen phosphate or cesium dihydrogen phosphate and silicon phosphate is preferably 1/4 to 2/1 in terms of molar ratio.

  Since the organic solid acid dissolves in the solvent, the compatibility with the binder component is good, and since the dispersibility becomes good when the electrolyte paste is produced, the effect of improving the quality of the electrolyte membrane is easily obtained. On the other hand, since an inorganic solid acid is excellent in heat resistance and durability, it is easy to obtain an effect that the mechanical strength after forming an electrolyte into a film becomes good.

  Although the said solid acid is not specifically limited, A particle size is about 0.1-200 micrometers in an electrolyte membrane, Preferably, it is about 0.1-150 micrometers. The solid acid alone before forming the electrolyte membrane also has a particle size of about 0.1 to 200 μm, preferably about 0.1 to 150 μm. When the particle size of the solid acid is about 0.1 to 200 μm, the dispersibility during the preparation of the electrolyte paste is improved, and an electrolyte membrane having a good film quality is easily obtained. In the present invention, the particle size of the solid acid can be measured using a scanning electron microscope (SEM) or the like.

<Binder>
The electrolyte membrane 1 may contain a binder in addition to the solid acid.

  The binder is not particularly limited as long as it has binding properties. For example, a fluorine polymer, a hydrocarbon polymer, a fluorine ionomer, a hydrocarbon ionomer, an ionic liquid, a cellulose polymer, or the like can be used. Especially, what has the acid resistance in pH 1-3 and the heat resistance in the temperature of about 50-300 degreeC is preferable. Further, it may have proton conductivity.

  Examples of the fluoropolymer include tetrafluoroethylene (PTFE), polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA). A fluorine-based resin or the like can be used.

  The hydrocarbon polymer is a polymer having a hydrocarbon compound as a main skeleton, such as polyimide, polyamideimide, polystyrene sulfide, polybenzimidazole, polypyridine, polypyrimidine, polyimidazole, polybenzothiazole, poly Examples thereof include benzooxazole, polyoxadiazol, polyxylone, polyquinoxaline, polythiadiazol, polytetrazabilene, polyoxazole, polythiazole, polyvinyl pyridine and polyvinyl imidazole.

  Examples of the fluorine-based ionomer include perfluorosulfonic acid type such as Nafion (registered trademark) of DuPont, Flemion (registered trademark) of Asahi Glass Co., and Aciplex (registered trademark) of Asahi Kasei Corporation, and Aquivio (registered trademark). Sulfonyl fluoride vinyl ether (SFVE) -tetrafluoroethylene copolymer and the like.

  Examples of the hydrocarbon ionomer 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 ionic liquid is not particularly limited as long as it does not interfere with proton conductivity, and examples thereof include fluorohydrogenate ionic liquid and diethylmethylammonium trifluoromethanesulfonic acid ionic liquid.

  Examples of the cellulose polymer include methyl cellulose, carboxymethyl cellulose, and cellulose acetate.

  Among the above-mentioned binders, PTFE, polyvinylidene fluoride, perfluorosulfonic acid, sulfonyl fluoride vinyl ether (SFVE) -tetrafluoroethylene copolymer cellulose acetate are preferable from the viewpoint of durability and binding properties. Moreover, the binder mentioned above may be used independently and may be used in combination of 1 or more types.

<Porous support>
The porous support 3 is not particularly limited as long as it is porous having pores. For example, a porous support composed of organic fibers, inorganic fibers and the like can be used. The form of the porous support 3 is not particularly limited, and examples thereof include a sheet form such as a nonwoven fabric and a woven cloth, and a thin film form such as a membrane filter. Moreover, as the porous support body 3, what has acid resistance in pH 1-3 and heat resistance in the temperature of about 50-300 degreeC is preferable, for example. Moreover, you may have proton conductivity.

  The porous support 3 preferably has a thickness of 10 to 500 μm, more preferably 20 to 300 μm. If the thickness is less than 10 μm, the strength of the porous support 3 may be significantly reduced, and it may be difficult to obtain strength as a reinforcing material for the electrolyte membrane. On the other hand, when the thickness exceeds 500 μm, it becomes too thick as a reinforcing material for the electrolyte membrane, and there is a fear that proton conductivity may be lowered.

  The porous support 3 preferably has a porosity of 40 to 98% by volume. More preferably, it is 60-96 volume%. When the porosity exceeds 98% by volume, the strength is remarkably lowered, and there is a possibility that it does not easily serve as a reinforcing material. On the other hand, if it is less than 40% by volume, proton conductivity may be lowered.

  In the present invention, the “porosity” can be measured, for example, as follows. The porosity calculated by measuring the thickness of the porous support of a given area with a micrometer, calculating the apparent volume, then calculating the actual volume by weight and specific gravity, and subtracting the actual volume from the apparent volume Is the porosity of the porous support.

  Further, the porous support 3 preferably has a pore diameter of 500 μm or less, more preferably 0.2 to 500 μm, and particularly preferably 5 to 400 μm. If the pore diameter is less than 0.2 μm, the porous support may be difficult to impregnate the electrolyte paste containing a small pore diameter and an electrolyte (solid acid). On the other hand, if the pore diameter exceeds 500 μm, the strength of the porous support may be significantly reduced, and it may be difficult to obtain strength as a reinforcing material for the electrolyte membrane. In the present invention, the “pore diameter” can be measured using, for example, SEM.

  The porous support 3 preferably has a fiber diameter (average diameter) of 30 μm or less, more preferably 0.2 to 30 μm. If the fiber warp is less than 0.2 μm, the strength of the porous support 3 may be significantly reduced, and it may be difficult to obtain strength as a reinforcing material for the electrolyte membrane. On the other hand, if the fiber diameter exceeds 30 μm, the reinforcing material for the electrolyte membrane becomes too thick and the proton conductivity may be lowered. Moreover, the porous support body 3 may be comprised by the organic fiber or inorganic fiber which has a 2 or more types of different fiber warp within the range of said fiber diameter.

  The organic fiber is not particularly limited, and examples thereof include fibrous polypropylene, polyester, polyethylene, polyamide, polyacrylonitrile, polyether sulfone, polyvinyl alcohol, polyvinyl chloride, polyphenylene sulfone, polyurethane, polytetrafluoroethylene, poly Examples include tetrafluoroethylene, polyphenylene sulfide, aramid, cellulose, cellulose triacetate, acrylic, polyolefin, polyurethane, and polyoxymethylene. The organic fiber has an advantage that a finer pore diameter can be obtained at a low cost.

  Examples of the inorganic fiber include glass fiber, carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, alumina whisker, silica whisker, ceramic fiber, and metal fiber. Among these, in terms of acid resistance and heat resistance, it is preferable to use glass fibers for inorganic fibers and polyacrylonitrile fibers for organic fibers, and more preferably glass fibers.

  In the case of a porous support composed of glass fibers (hereinafter also referred to as a glass fiber support), the fiber diameter (average diameter) of the glass fibers is preferably 20 μm or less, and is 0.3 to 20 μm. It is more preferable. If the fiber diameter is less than 0.3 μm, the strength of the glass fiber support may be remarkably lowered, and it may be difficult to obtain strength as a reinforcing material for the electrolyte membrane. On the other hand, if the fiber diameter exceeds 20 μm, the reinforcing material for the electrolyte membrane becomes too thick and the proton conductivity may be lowered. The glass fiber support may be composed of two or more glass fibers having different fiber diameters. From the viewpoint of easy availability, it is preferable to use glass cloth or glass fiber nonwoven fabric as the glass fiber support.

  Moreover, in the said glass fiber support, when a resin component is included as a binding component which binds glass fibers, it is preferable that the content rate of the glass fiber in a glass fiber support is 50-98 mass%. When the content ratio of the glass fiber in the glass fiber support is 50 to 98% by mass, a glass fiber support having a strength capable of serving as a reinforcing material for the electrolyte membrane is obtained.

  The binding component is not particularly limited as long as it binds glass fibers to each other, but is preferably excellent in heat resistance and acid resistance. For example, beaten cellulose, acrylic fiber, acrylic resin emulsion, fluororesin dispersion, colloidal silica, epoxy resin and the like can be used. By including a binder component in the glass fiber support to bind the glass fibers together, the mechanical properties of the porous support are improved.

  The glass fiber support preferably has a thickness of 10 to 200 μm, more preferably 20 to 150 μm. If the thickness is less than 10 μm, the strength of the glass fiber support may be significantly reduced, and it may be difficult to obtain strength as a reinforcing material for the electrolyte membrane. On the other hand, when the thickness exceeds 200 μm, it becomes too thick as a reinforcing material for the electrolyte membrane, and the proton conductivity may be lowered.

  The glass fiber support preferably has a porosity of 50 to 98% by volume. More preferably, it is 80-96 volume%. When the porosity exceeds 98% by volume, the strength is remarkably lowered, and there is a possibility that it does not easily serve as a reinforcing material. On the other hand, if the porosity is less than 50% by volume, proton conductivity may be lowered.

  The glass fiber support preferably has a pore diameter of 400 μm or less, more preferably 0.2 to 400 μm, and particularly preferably 10 to 360 μm. If the pore diameter is less than 0.2 μm, the porous support may be difficult to impregnate the electrolyte paste containing a small pore diameter and an electrolyte (solid acid). On the other hand, if the pore diameter exceeds 400 μm, the strength of the porous support may be significantly reduced, and it may be difficult to obtain strength as a reinforcing material for the electrolyte membrane.

[Catalyst layer]
The catalyst layers 2a and 2b contain a catalyst. The catalyst is not particularly limited as long as it is a substance that promotes the anode and / or cathode reaction in the fuel cell. For example, platinum-supported carbon, platinum-ruthenium-supported carbon, platinum-cobalt-supported carbon, gold-supported carbon, silver-supported carbon, iron-cobalt-nickel-supported carbon, etc., metal-supported carbon, platinum black, platinum-ruthenium black, platinum-cobalt Examples thereof include metal fine particles such as black, gold black and silver black, and inorganic substances such as molybdenum carbide. Among these, platinum-supporting carbon having high catalytic activity, molybdenum carbide with little phosphoric acid poisoning, and the like are preferable.

  The catalyst layers 2a and 2b preferably contain a solid acid in addition to the catalyst. As the solid acid, those described above can be used, and from the viewpoint of adhesion, it is preferable to contain the same solid acid as the electrolyte membrane.

  The catalyst layers 2a and 2b may contain a binder. The catalyst layer can be molded only with a solid acid and a catalyst, but a catalyst layer having excellent mechanical strength can be obtained by coating and molding a paste obtained by adding a binder thereto. As the binder, those described above can be used.

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

  In the catalyst layer-electrolyte membrane laminate 10 of Embodiment 1, as shown in FIGS. 1A to 1E, the porous support 3 includes the electrolyte membrane 1 and at least a part of one or both of the catalyst layers 2 a and 2 b. It penetrates. Thereby, even if the electrolyte membrane is a thin film, the strength of the membrane can be increased, and the adhesion between the catalyst layer and the electrolyte membrane is also improved. In addition, the catalyst layer-electrolyte membrane laminate 10 has the porous support 3 as shown in FIGS. 1C to 1E from the viewpoint of further improving the membrane strength of the electrolyte membrane and the adhesion between the catalyst layer and the electrolyte membrane. The electrolyte membrane 1 and the catalyst layers 2a and 2b are preferably partially or entirely penetrated.

  Hereinafter, the manufacturing method of the catalyst layer-electrolyte membrane laminated body 10 of Embodiment 1 is demonstrated.

  The catalyst layer-electrolyte membrane laminate 10 is not particularly limited, but is preferably manufactured as follows, for example. Specifically, as shown in FIGS. 2A to 2E, the method for manufacturing the catalyst layer-electrolyte membrane laminate 10 includes forming a catalyst layer 2 b including a catalyst and having a porous support 3 at least partially. A step of forming an electrolyte membrane 1 comprising a solid acid and comprising a porous support 3; comprising a catalyst and comprising at least a portion of the porous support 3 or not having a porous support 3 Forming the catalyst layer 2a.

  First, a porous support is prepared. As the porous support, those described above can be used.

<Formation of catalyst layer 2b>
Next, the catalyst paste is impregnated into the porous support and dried to form the catalyst layer 2b having at least a part of the porous support as shown in FIGS. As shown in FIGS. 2A and 2D, the catalyst layer 2b having a porous support in part has a protruding portion from the porous support.

  The catalyst paste is obtained by mixing and dispersing a mixture containing a catalyst, a solid acid, and a solvent with a disperser. As the disperser, an ultrasonic disperser, a homogenizer, a ball mill, or the like can be used.

  In addition, what was mentioned above should just be used as a catalyst and a solid acid. The solvent is not particularly limited as long as it can disperse the catalyst and the solid acid, and examples thereof include water, ethanol, methanol, 1-butanol, t-butanol, propanol, N-methylpyrrolidone, dimethylacetamide and the like. Can be used.

  In the catalyst paste, the concentration of the solid content composed of the catalyst and the solid acid is preferably 2 to 50% by mass, more preferably 5 to 20% by mass from the viewpoint of coatability. Further, the blending amount of the catalyst and the solid acid is preferably 1/2 to 1 / 0.1, more preferably 1/1 to 1 / 0.25, in terms of mass ratio.

  The catalyst paste may further contain a binder. The amount of the binder (solid content) added is preferably 2 to 50 mass%, more preferably 5 to 40 mass%, based on the solid content in the catalyst paste. In this case, after adding the catalyst and the solid acid to the binder solution or dispersion, a catalyst paste may be prepared by adding a solvent. 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 type of binder used in the catalyst layer, the type of solvent, and the blending ratio may be the same as or different from those of the electrolyte membrane. When the binder used for the electrolyte membrane and the binder used for the catalyst layer are different types, the glass transition point or softening point of at least one binder contained in the electrolyte membrane and the catalyst layer is considered from the viewpoint of the adhesion between the electrolyte membrane and the catalyst layer. The difference is preferably about 50 ° C. or less.

The impregnation of the catalyst paste into the porous support is not particularly limited, but can be performed, for example, by applying the catalyst paste to the porous support. The coating method is not particularly limited, for example,
Screen printing, blade coating, die coating, spray coating, dispenser coating, inkjet coating, and the like can be used. Among these, it is preferable to use screen printing or blade coating from the standpoint of easy preparation of the catalyst paste.

The coating amount of the catalyst paste, for example, when using a platinum-supported carbon as the catalyst, about 0.1 to 2.0 mg / cm ² platinum loading amount, preferably from about 0.5 to 1.5 mg / cm ² It is.

  The drying temperature is, for example, about 50 to 300 ° C, preferably about 100 to 250 ° C. If the drying temperature is lower than about 50 ° C., the solvent contained in the catalyst paste may not be removed. On the other hand, when the drying temperature exceeds about 300 ° C., the binder may be thermally decomposed. The drying time is, for example, about 10 minutes to 5 hours, preferably about 10 minutes to 3 hours.

<Formation of electrolyte membrane 1>
Next, after impregnating the porous support 3 with an electrolyte paste containing a solid acid and a binder, the porous support 3 is dried on the catalyst layer 2b as shown in FIGS. Is formed. In addition, what is necessary is just to use the above-mentioned thing as a solid acid and a binder.

  The electrolyte paste is obtained by mixing and dispersing a mixture containing a solid acid and a binder with a disperser. As the disperser, an ultrasonic disperser, a homogenizer, a ball mill, or the like can be used.

  The electrolyte paste may further contain a solvent. The solvent is not particularly limited as long as it does not aggregate the binder. For example, water, ethanol, methanol, 1-butanol, t-butanol, propanol, N-methylpyrrolidone, dimethylacetamide and the like can be used. . In this case, an electrolyte paste may be prepared by adding a solvent after adding a solid acid to the solution or dispersion of the binder.

  In the above-described electrolyte paste, the solid content of the solid acid and the binder is preferably 10/1 to 10/3, and preferably 10/1, in terms of mass ratio from the viewpoints of self-sustainability and battery performance. More preferred.

  Note that the particle size of the solid acid in the electrolyte paste may vary depending on the dispersion method or the type of binder. In this case, a porous support 3 having a different pore diameter can be used accordingly.

  The impregnation of the porous paste 3 with the electrolyte paste is not particularly limited. For example, knife coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater, screen printing, rolling It can carry out using general methods, such as a method.

  The drying temperature is about 50 to 300 ° C, preferably about 100 to 250 ° C. If the drying temperature is lower than about 50 ° C, the solvent contained in the paste may not be removed, and if it exceeds about 300 ° C, the binder may be thermally decomposed. The drying time is about 10 minutes to 5 hours, preferably about 10 minutes to 3 hours.

  In addition, when using a metal phosphate as a solid acid, a metal phosphate can be made into powder form, the above-mentioned phosphoric acid and a binder can be added, and it can mix and disperse | distribute as mentioned above, and can produce electrolyte paste. Alternatively, as post-baking, after adding a predetermined amount of phosphoric acid to the metal phosphate, a binder is added to the powder that has been baked at a temperature of about 100 to 200 ° C. for about 30 minutes to 2 hours to prepare an electrolyte paste. Also good. In the above, 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. Adjust to 8-5 / 1, most preferably 5 / 0.9. Then, the water contained in phosphoric acid is volatilized by the drying treatment, and orthophosphoric acid on the metal phosphate is condensed to produce pyrophosphoric acid or metaphosphoric acid. Then, the pyrophosphoric acid or metaphosphoric acid, etc. and the metal phosphate are cross-linked to form a network with phosphoric acid around the metal phosphate, and the chargeable phosphoric acid accumulates at a high density, which is favorable. It is considered that proton conductivity is exhibited and the strength of the electrolyte is increased.

<Formation of catalyst layer 2a>
Next, a catalyst paste is produced in the same manner as in the case of the catalyst layer 2b. By impregnating the obtained catalyst paste into the porous support 3 and drying, the catalyst layer 2a including the porous support 3 at least partially on the electrolyte membrane 1 as shown in FIGS. Form. Alternatively, the catalyst layer 2a not provided with the porous support 3 on the electrolyte membrane 1 can be formed by directly applying the catalyst paste on the electrolyte membrane 1 and drying it, as shown in FIGS. 2A and 2B. Form. As shown in FIGS. 2C and 2D, the catalyst layer 2a including the porous support 3 in part has a protruding portion from the porous support.

  In the above description, the order of the catalyst layer 2b, the electrolyte membrane 1, and the catalyst layer 2a has been described. However, the order is not particularly limited, and the catalyst layer 2a, the electrolyte membrane 1, and the catalyst layer 2b may be formed in this order. In addition, when the catalyst layer 2a does not include a porous support as shown in FIGS. 1A and 1B, in addition to the above, the electrolyte membrane 1, the catalyst layer 2b, and the catalyst layer 2a may be formed in this order. You may form in order of the electrolyte membrane 1, the catalyst layer 2a, and the catalyst layer 2b.

  As described above, the catalyst layer-electrolyte membrane laminate 10 in which the porous support 3 passes through the electrolyte membrane 1 and at least a part of at least one of the catalyst layers 2a and 2b is obtained.

[Embodiment 2]
Hereinafter, a membrane electrode assembly will be described as Embodiment 2 of the present invention.

(Membrane electrode assembly)
FIG. 3 is a schematic cross-sectional view showing an example of a membrane electrode assembly according to Embodiment 2 of the present invention. As shown in FIG. 3, the membrane electrode assembly 20 according to Embodiment 2 of the present invention includes the catalyst layer-electrolyte membrane laminate 10 shown in Embodiment 1 and a pair of gas diffusion layers 14a and 14b. Gas diffusion layers 14 a and 14 b are disposed on both surfaces of the catalyst layer-electrolyte membrane laminate 10, respectively. In FIG. 3, the same parts as those in FIG. 3 and FIG. 1 have the same functions.

  The gas diffusion layers 14a and 14b are made of a conductive material having gas diffusibility, such as a porous body, so that fuel gas or oxidant gas can flow therethrough.

  The thicknesses of the gas diffusion layers 14a and 14b may be appropriately determined in consideration of the thickness of the catalyst layer and the electrolyte membrane. The thickness is, for example, about 200 to 400 μm, preferably about 250 to 350 μm.

  The membrane electrode assembly 20 according to the present embodiment is manufactured by using the catalyst layer-electrolyte membrane laminate 10 shown in the first embodiment and bonding the gas diffusion layers 14a and 14b to both surfaces thereof by pressure bonding or the like. Can do. In this case, the catalyst layer 2a and the gas diffusion layer 14a constitute a cathode side catalyst electrode, and the catalyst layer 2b and the gas diffusion layer 14b constitute an anode side catalyst electrode. Alternatively, the catalyst layer 2a and the gas diffusion layer 14a may constitute an anode side catalyst electrode, and the catalyst layer 2b and the gas diffusion layer 14b may constitute a cathode side catalyst electrode.

  In addition, when the catalyst layer 2a is not provided with the porous support body, you may produce the membrane electrode assembly 20 as follows, for example. First, as shown in FIGS. 2A to 2B, the catalyst layer 2b and the electrolyte membrane 1 are formed on the catalyst layer 2b. Next, a catalyst electrode is directly joined on the electrolyte membrane 1. Next, the gas diffusion layer 14b is bonded onto the catalyst layer 2b by pressure bonding or the like. Alternatively, the gas diffusion layer 14b may be bonded to the catalyst layer 2b by pressure bonding or the like, and then the catalyst electrode may be directly bonded to the electrolyte membrane 1. That is, in this embodiment, the catalyst electrode serves as a catalyst layer and a gas diffusion layer. The catalyst electrode is composed of a catalyst and a conductive material having gas diffusibility, such as a porous body, so that fuel gas or oxidant gas can flow therethrough. In addition, what is necessary is just to determine the thickness of a catalyst electrode suitably considering the kind of electrode base material, the thickness of an electrolyte membrane, etc., for example, about 20-3000 micrometers, Preferably, it is about 30-2000 micrometers.

[Embodiment 3]
Hereinafter, a fuel cell will be described as a third embodiment of the present invention.

(Fuel cell)
FIG. 4 is a schematic cross-sectional view showing an example of a fuel cell according to Embodiment 3 of the present invention. As shown in FIG. 4, the fuel cell 30 according to Embodiment 4 of the present invention includes the catalyst layer-electrolyte membrane laminate 10 shown in Embodiment 1, a pair of gas diffusion layers 14 a and 14 b, and a pair of separators 28. , 29, and gas diffusion layers 14 a, 14 b and separators 28, 29 are sequentially laminated on both surfaces of the catalyst layer-electrolyte membrane laminate 10. In FIG. 4, the same parts as those in FIGS. 1 and 3 are denoted by the same reference numerals, and redundant description is omitted. 4 and FIG. 1 and FIG. 3 have the same functions.

  The separator 29 is for supplying fuel to the anode side catalyst electrode, and has a fuel flow path 21 for circulating the fuel. On the other hand, the separator 28 is for supplying an oxidant gas to the cathode side catalyst electrode, and has an oxidant gas flow path 22 for circulating the oxidant gas.

  The separators 28 and 29 may be made of any material that has stable conductivity even in the environment inside the fuel cell 30. In general, a carbon plate having a flow path is used. The separators 28 and 29 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 28 and 29 can have a function as a current collector when used in a fuel cell in which a plurality of fuel cells 30 are stacked.

<Operating principle of fuel cell>
A fuel capable of supplying hydrogen, such as hydrogen gas or methanol, is supplied to the anode catalyst electrode through the fuel flow path 21, and protons (H ⁺ ) and electrons (e ⁻ ) are generated from the fuel. The generated protons are conveyed to the cathode side catalyst electrode by the electrolyte membrane 1. On the other hand, oxidant gas such as air or oxygen gas is supplied to the cathode side catalyst electrode through the oxidant gas flow path 22, protons carried by the electrolyte membrane 1, electrons and oxidant gas coming from the external circuit 23, and Reacts to produce water. In this way, it functions as a fuel cell.

  In the fuel cell 30 according to the present embodiment, separators 28 and 29 are respectively laminated on both surfaces of the membrane electrode assembly 20 obtained as described above by using a known technique used for manufacturing a fuel cell. Can be manufactured.

  According to this embodiment, it is possible to provide a high-performance fuel cell 30 that is excellent in stability.

  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
<Preparation of solid acid>
As a solid acid, tin phosphate was prepared as follows. 13.40 g (0.09 mol) of tin oxide (SnO ₂ , manufactured by Nano Tec), 1.40 g (0.0050 mol) of indium oxide (In ₂ O ₃ , manufactured by Nacalai Tesque), and hydrogen phosphate 2 27.99 g (0.212 mol) of ammonium (Nacalai Tesque) was added and mixed. The obtained mixture was put into a crucible, fired at about 650 ° C. for about 2 hours, and the product obtained after sintering was pulverized with an agate nail to obtain a tin phosphate having a particle size of 28.4 μm. . In addition, the particle size of tin phosphate was measured as follows.

<Production of catalyst layer-electrolyte membrane laminate>
0.5 g of tin phosphate obtained above, 1 g of platinum-supported carbon (“TEC10E50E” manufactured by Tanaka Kikinzoku Co., Ltd.), 2.5 g of binder (“Nafion2020CS” manufactured by Dupont), solvent (1 n-butanol and t-butanol) (Mixed at a mass ratio of / 1) 6.0 g was mixed and mixed for about 3 hours by a disperser to prepare a catalyst paste. As shown in FIG. 2D, the obtained catalyst paste was blade coated on a glass fiber support 3 having a thickness of 110 μm, a porosity of 95%, a fiber diameter of 10 μm, and a pore diameter of 100 μm, and a (total) thickness of 30 μm, Coating was performed so that the thickness of the protruding portion from the glass fiber support was 10 μm, and drying was performed at about 100 ° C. for about 30 minutes, thereby forming a catalyst layer 2b partially including the porous support 3.

  Next, 0.9 g of 85% phosphoric acid aqueous solution, 0.83 g of 60% PTFE dispersion (“Polyflon D1-E” manufactured by Daikin Industries, Ltd.) and 20 g of water were added to 5 g of tin phosphate obtained above, To prepare an electrolyte paste. As shown in FIG. 2D, the obtained electrolyte paste was applied onto the catalyst layer 2b with a blade coater, dried at about 160 ° C. for about 30 minutes, and had a thickness of 70 μm. The provided electrolyte membrane 1 was formed on the catalyst layer 2b.

  Next, the catalyst paste obtained above is applied onto the electrolyte membrane 1 with a blade coater so that the (total) thickness is 30 μm and the thickness of the protruding portion from the glass fiber support is 10 μm as shown in FIG. 2D. And dried at about 100 ° C. for about 30 minutes to form a catalyst layer 2 a partially including the porous support 3 on the electrolyte membrane 1 to obtain a catalyst layer-electrolyte membrane laminate 10. .

<Preparation of membrane electrode assembly>
As shown in FIG. 3, gas diffusion layers 14 a and 14 b (“TGH-090” manufactured by Toray Industries, Inc.) are bonded to both surfaces of the catalyst layer-electrolyte membrane laminate 10 obtained above to form a membrane electrode assembly. And assembled into a JARI cell standard cell. The JARI cell standard cell is used for the basic research of PEFC and the evaluation test of PEFC materials (membranes, electrode catalysts, components, etc.) at the Japan Automobile Research Institute (JARI). It means the developed cell.

(Example 2)
<Production of catalyst layer-electrolyte membrane laminate>
First, the catalyst layer 2b partially including the porous support 3 in the same manner as in Example 1 except that the (total) thickness was 40 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. Formed.

  Next, an electrolyte membrane 1 provided with the porous support 3 was formed on the catalyst layer 2b in the same manner as in Example 1 except that the thickness was 50 μm.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 1 except that the (total) thickness was 40 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Example 3)
<Production of catalyst layer-electrolyte membrane laminate>
First, a catalyst layer 2b partially including the porous support 3 in the same manner as in Example 1 except that the (total) thickness is 55 μm and the thickness of the protruding portion from the glass fiber support is 10 μm. Formed.

  Next, an electrolyte membrane 1 provided with the porous support 3 was formed on the catalyst layer 2b in the same manner as in Example 1 except that the thickness was 20 μm.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 1 except that the (total) thickness was 55 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Example 4)
<Production of catalyst layer-electrolyte membrane laminate>
First, a catalyst layer partially including the porous support 3 in the same manner as in Example 1 except that the (total) thickness is 50 μm and the thickness of the protruding portion from the glass fiber support is 30 μm. 2b was formed.

  Next, in the same manner as in Example 1, an electrolyte membrane 1 having a thickness of 70 μm and provided with a porous support 3 was formed on the catalyst layer 2b.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 1 except that the (total) thickness was 50 μm and the thickness of the protruding portion from the glass fiber support was 30 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Example 5)
<Production of catalyst layer-electrolyte membrane laminate>
First, a catalyst layer partially including the porous support 3 in the same manner as in Example 1 except that the (total) thickness is 70 μm and the thickness of the protruding portion from the glass fiber support is 50 μm. 2b was formed.

  Next, in the same manner as in Example 1, an electrolyte membrane 1 having a thickness of 70 μm and provided with a porous support 3 was formed on the catalyst layer 2b.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 1 except that the (total) thickness was 70 μm and the thickness of the protruding portion from the glass fiber support was 50 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Example 6)
<Production of catalyst layer-electrolyte membrane laminate>
A glass fiber support having a thickness of 60 μm, a porosity of 96%, a fiber diameter of 10 μm, and a pore diameter of 200 μm was used. In the same manner as in Example 1, a catalyst layer 2b having a porous support 3 in part was formed.

  Next, an electrolyte membrane 1 provided with the porous support 3 was formed on the catalyst layer 2b in the same manner as in Example 1 except that the thickness was 40 μm.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 1 except that the (total) thickness was 20 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Example 7)
<Production of catalyst layer-electrolyte membrane laminate>
The catalyst layer 2b provided with a part of the porous support 3 in the same manner as in Example 6 except that the (total) thickness was 25 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. Formed.

  Next, an electrolyte membrane 1 provided with the porous support 3 was formed on the catalyst layer 2b in the same manner as in Example 6 except that the thickness was 30 μm.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 6 except that the (total) thickness was 25 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Example 8)
<Production of catalyst layer-electrolyte membrane laminate>
Except that the total thickness is 30 μm and the thickness of the protruding portion from the glass fiber support is 10 μm, the catalyst layer 2b partially including the porous support 3 is provided in the same manner as in Example 6. Formed.

  Next, an electrolyte membrane 1 provided with the porous support 3 was formed on the catalyst layer 2b in the same manner as in Example 6 except that the thickness was 20 μm.

  Next, a catalyst provided with a part of the porous support 3 in the same manner as in Example 6 except that the (total) thickness was 30 μm and the thickness of the protruding portion from the glass fiber support was 10 μm. The layer 2a was formed on the electrolyte membrane 1, and the catalyst layer-electrolyte membrane laminated body 10 was obtained.

<Preparation of membrane electrode assembly>
Using the catalyst layer-electrolyte membrane laminate 10 obtained above, a membrane / electrode assembly was obtained in the same manner as in Example 1 and assembled into a JARI cell standard cell.

(Comparative Example 1)
The electrolyte paste obtained in the same manner as in Example 1 was coated with a blade coater on a glass fiber support having a thickness of 20 μm, a porosity of 85%, a fiber diameter of 2 μm, and a pore diameter of 15 μm, and at about 100 ° C., about 30 An electrolyte membrane having a thickness of 20 μm was obtained by drying for a minute.

  The particle diameter of the electrolyte (tin phosphate) used in the examples and comparative examples, the particle diameter of the electrolyte (tin phosphate) in the electrolyte membranes in the examples and comparative examples, and the occurrence of the JARI cell standard cell obtained in the examples The adhesion between the electrolyte membrane and the catalyst layer in the power layer and the catalyst layer-electrolyte membrane laminate of the example was measured as follows, and the results are shown in Table 1 below. In addition, the pore diameter and porosity of the porous support used in the examples and comparative examples were measured as follows.

(Measurement of electrolyte particle size)
Two SEM photographs of the electrolyte alone were taken at a magnification of 250 times, the secondary particle diameter of the electrolyte was measured at each N5, and the average particle diameter of the total N10 was taken as the electrolyte particle diameter. As the SEM apparatus, “JSM-6700F” manufactured by JEOL was used. In addition, in FIG. 5, the SEM photograph of the magnification 250 times of the tin phosphate used in the Example is shown.

(Measurement of particle size of electrolyte in electrolyte membrane)
Five cross-sectional SEM photographs of the electrolyte membrane 1 were taken at a magnification of 30,000, the particle diameter of the electrolyte in the electrolyte membrane was measured at each N4, and the average particle size of N20 in total was taken as the particle size of the electrolyte in the electrolyte membrane. In addition, in FIG. 6, the SEM photograph of the magnification of 30,000 times of the tin phosphate in the electrolyte membrane in Example 1 is shown.

(Measurement of electromotive force)
Using the JARI cell standard cell obtained in the example, IV measurement was performed at 120 ° C. using a non-humidified gas, and the electromotive force at 100 mA / cm ² was examined.

(Evaluation of adhesion)
After pasting a commercially available cellophane tape ("CT405AP-18" manufactured by Nichiban Co., Ltd., width 18 mm, length 35 mm) on the surface of the catalyst layer on one side of the catalyst layer-electrolyte membrane laminate obtained in the examples, about 1 mm / The adhesion between the electrolyte membrane and the catalyst layer was examined by pulling at a rate of minutes and peeling off the cellophane tape, and evaluated in three stages as follows. The other catalyst layer and the electrolyte membrane of the catalyst layer-electrolyte membrane laminate were fixed on a polyethylene terephthalate (PET) film so as not to peel off.
A: Only the cellophane tape is peeled off.
B: A thin catalyst layer is attached to the cellophane tape and peeled off.
C: The catalyst layer sticks to and peels off from the cellophane tape to the extent that the catalyst layer is visible on the electrolyte membrane side.

(Measurement of pore diameter of porous support)
Five SEM photographs of the surface of the porous support were taken at a magnification of 100, the pore diameter of the porous support was measured at each N5, and the average pore diameter of the total N20 was taken as the pore diameter of the porous support.

(Porosity measurement of porous support)
The thickness of the porous support alone having a predetermined area was measured with a micrometer, and the apparent volume was calculated. Thereafter, the actual volume was calculated from the weight and specific gravity, and the porosity calculated by subtracting the actual volume from the apparent volume was defined as the porosity of the porous support.

  In Examples 1 to 8, in which the porous support penetrates at least part of one or both of the electrolyte membrane and the catalyst layer, the electrolyte membrane is excellent in strength even if it is a thin film, and membrane breakage does not occur when the catalyst layer is formed. Moreover, as shown in the said Table 1, in the adhesive evaluation, the remarkable peeling of the catalyst layer was not confirmed, and the adhesiveness between the electrolyte membrane and the catalyst layer was good. On the other hand, in Comparative Example 1, since the thickness of the porous support is thin and the strength is insufficient, film breakage occurs during the formation of the catalyst layer, making it difficult to form the membrane-electrode assembly, and confirming the adhesion. It was also confirmed that it was difficult.

Further, as shown in Table 1, in Examples 1 to 8, the electrolyte membrane can be thinned while maintaining the strength, and an electromotive force of 0.3 V or more was exhibited at 100 mA / cm ² . On the other hand, in Comparative Example 1, since it was difficult to form a membrane electrode assembly, it was confirmed that battery characteristic evaluation was difficult.

  The present invention can be suitably applied to technical fields related to an electrolyte membrane using a solid acid and a fuel cell using the electrolyte membrane.

DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 2a, 2b Catalyst layer 3 Porous support body 10 Catalyst layer-electrolyte membrane laminated body 14a, 14b Gas diffusion layer 20 Membrane electrode assembly 21 Fuel flow path 22 Oxidant gas flow path 23 External circuit 28, 29 Separator 30 Fuel cell

Claims (13)

A catalyst layer-electrolyte membrane laminate including an electrolyte membrane and a pair of catalyst layers,
The electrolyte membrane includes a solid acid and includes a porous support;
The catalyst layer includes a catalyst and is bonded to both surfaces of the electrolyte membrane,
The catalyst layer-electrolyte membrane laminate, wherein the porous support passes through part of one or both of the electrolyte membrane and at least the catalyst layer.   The catalyst layer-electrolyte membrane laminate according to claim 1, wherein the porous support penetrates part or all of the electrolyte membrane and both catalyst layers.   The catalyst layer-electrolyte membrane laminate according to claim 1 or 2, wherein the solid acid is an inorganic solid acid.   The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 3, wherein the solid acid is an inorganic salt having proton conductivity. The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 4, wherein the solid acid is a metal phosphate represented by the following formula (1).
M _1-x N _x P ₂ O ₇ (1)
However, in Formula (1), X is 0 ≦ X <0.5, and M is a group consisting of Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na, and Al. N is one selected from the group consisting of Al, In, B, Ga, Sc, Yb, Ce, La, Sb, Y, Nb and Mg.   The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 5, wherein the solid acid is tin phosphate.   The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 4, wherein the solid acid is a complex of a heteropolyacid and an inorganic salt.   5. The solid acid is a kind selected from the group consisting of a complex of tungsten phosphate and potassium hydrogen sulfate, a complex of tungsten phosphate and cesium hydrogen sulfate, and a complex of tungsten phosphate and cesium sulfate. The catalyst layer-electrolyte membrane laminate according to any one of the above.   The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 4, wherein the solid acid is a composite of cesium phosphoric acid and silicon phosphate.   The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 9, wherein the porous support is composed of glass fibers.   A catalyst layer-electrolyte membrane laminate according to claim 1 and a pair of gas diffusion layers, wherein the gas diffusion layers are respectively disposed on both sides of the catalyst layer-electrolyte membrane laminate. Membrane electrode assembly.   The catalyst layer-electrolyte membrane laminate according to claim 1, a pair of gas diffusion layers, and a pair of separators, wherein the gas diffusion layer and the separator are on both sides of the catalyst layer-electrolyte membrane laminate. A fuel cell characterized by being sequentially laminated. A method for producing a catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 10,
Forming a catalyst layer comprising a catalyst and comprising a porous support at least in part;
Forming an electrolyte membrane comprising a solid acid and comprising a porous support;
Forming the other catalyst layer comprising a catalyst and having a porous support at least partially or not having a porous support,
Production of catalyst layer-electrolyte membrane laminate characterized in that the porous support body obtains a catalyst layer-electrolyte membrane laminate in which the electrolyte membrane and at least one of or both of the catalyst layers penetrate. Method.

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