JP2012195197A - Electrolyte membrane, and catalyst layer-electrolyte membrane laminate, membrane electrode assembly and fuel cell including the electrolyte membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an electrolyte membrane excellent in mechanical strength, having favorable ion conductivity in a non-humidified state and preventing a liquid electrolyte from steeping from the electrolyte membrane; and a catalyst layer-electrolyte membrane laminate, a membrane electrode assembly and a fuel cell which include the electrolyte membrane.SOLUTION: An electrolyte membrane 10 of the present invention is an electrolyte membrane including a liquid electrolyte and a solid acid, and includes at least a first layer 1 and a second layer 2. The first layer 1 includes the solid acid and the second layer 2 includes the liquid electrolyte, and the first layer 1 is arranged at an outermost layer on one side or both sides of the electrolyte membrane 10.

Description

  The present invention relates to an electrolyte membrane, and a catalyst layer-electrolyte membrane laminate, a membrane electrode assembly 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. 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 the proton conduction mechanism is a transport mechanism that conducts protons in the state of H ₃ O ^+. For this reason, it is necessary to provide a humidifying mechanism, which causes a problem that the system becomes complicated.

  Thus, an ionic liquid has been proposed as a liquid electrolyte having ionic conductivity in a non-humidified state (see, for example, Patent Document 1). Patent Documents 2 to 4 propose electrolytes containing an ionic liquid and a solid acid.

  However, since the ionic liquid proposed in Patent Document 1 is a liquid, there is a problem that moldability is difficult. Therefore, in Patent Document 5, a binder is added to the ionic liquid to form a film. However, if the binder is added, the ionic conductivity inherent in the electrolyte may be impaired. When the ionic liquid is increased in order to improve the ionic conductivity of the electrolyte membrane, there is a problem that the ionic liquid penetrates into the pores of the catalyst layer from the electrolyte membrane and blocks the gas flow path.

  Further, even when a solid acid is mixed in an ionic liquid as proposed in Patent Documents 2 to 4, if the amount of the ionic liquid is large, the ionic liquid permeates into the pores of the catalyst layer from the electrolyte membrane. There is a problem of blocking the road.

Patent No. 4036279 JP 2010-84159 A JP 2009-16156 A JP 2004-515351 A JP 2006-32213 A

  In order to solve the above-described conventional problems, the present invention provides an electrolyte membrane excellent in mechanical strength, having good ionic conductivity in a non-humidified state, and preventing exudation of a liquid electrolyte from the electrolyte membrane, and There are provided a catalyst layer-electrolyte membrane laminate, a membrane electrode assembly and a fuel cell using the same.

  The electrolyte membrane of the present invention is an electrolyte membrane containing a liquid electrolyte and a solid acid, and includes at least a first layer and a second layer, the first layer containing a solid acid, and the second layer. Includes a liquid electrolyte, and the first layer is disposed on the outermost layer on one or both sides of the electrolyte membrane.

  The catalyst layer-electrolyte membrane laminate of the present invention comprises the electrolyte membrane of the present invention and a pair of catalyst layers, wherein the catalyst layers are respectively disposed on both main surfaces of the electrolyte membrane. To do.

  The membrane electrode assembly of the present invention includes the electrolyte membrane of the present invention and a pair of catalyst electrodes, and the catalyst electrodes are respectively disposed on both main surfaces of the electrolyte membrane.

  The fuel cell of the present invention comprises the electrolyte membrane of the present invention, a pair of catalyst electrodes, and a pair of separators, and the catalyst electrodes and the separators are laminated in this order on both main surfaces of the electrolyte membrane. It is characterized by being.

  The present invention includes a first layer containing a solid acid and a second layer containing a liquid electrolyte. By arranging the first layer on the outermost layer on one side or both sides of the electrolyte membrane, the mechanical strength is increased. An electrolyte membrane that is excellent and has good ionic conductivity in a non-humidified state, while preventing the liquid electrolyte from seeping out from the electrolyte membrane, and a catalyst layer-electrolyte membrane laminate, membrane electrode assembly using the electrolyte membrane A fuel cell can be provided.

1A is a schematic cross-sectional view showing an example of an electrolyte membrane according to Embodiment 1 of the present invention, and FIG. 1B is a schematic cross-sectional view showing another example of the electrolyte membrane according to Embodiment 1 of the present invention. FIG. 1C is a schematic cross-sectional view showing still another example of the electrolyte membrane according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a catalyst layer-electrolyte membrane laminate according to Embodiment 2 of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of a membrane electrode assembly according to Embodiment 3 of the present invention. FIG. 4 is a schematic cross-sectional view showing an example of a fuel cell according to Embodiment 4 of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the embodiments described below 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. Not what you want. The technical idea of the present invention can be variously modified within the scope of the claims.

  In the present invention, the “liquid electrolyte” means a liquid substance having ionic conductivity. Further, in the present invention, the “solid acid” means a solid that exhibits acid characteristics.

[Embodiment 1]
First, an electrolyte membrane will be described as Embodiment 1 of the present invention.

(Electrolyte membrane)
FIG. 1A is a schematic cross-sectional view showing an example of an electrolyte membrane according to Embodiment 1 of the present invention. As shown in FIG. 1A, the electrolyte membrane 10 includes two layers, a first layer 1 and a second layer 2, and the first layer 1 is disposed on the outermost layer on one side of the electrolyte membrane 10. . The first layer 1 includes a solid acid, and the second layer 2 includes a liquid electrolyte. Further, from the viewpoint of enhancing ion conductivity, the second layer 2 may further contain a solid acid, and the solid acid contained in the second layer 2 is the same kind as the solid acid contained in the first layer 1. It may be a different type. Further, the first layer 1 and / or the second layer 2 may contain a binder. When the first layer and / or the second layer contains a binder, the moldability becomes better and the mechanical strength becomes higher.

  1B and 1C are schematic cross-sectional views showing other examples of the electrolyte membrane according to Embodiment 1 of the present invention. FIG. 1B is a schematic cross-sectional view showing an electrolyte membrane having three layers, and FIG. 1C is a schematic cross-sectional view showing an electrolyte membrane having five layers. In FIG. 1B and FIG. 1C, the same code | symbol is attached | subjected to FIG. 1A and the same part, and the same part has the same function. When the electrolyte membrane 10 has three or more layers, it is preferable that the first layer 1 is disposed on the outermost layers on both sides of the electrolyte membrane 10 as shown in FIGS. 1B and 1C. It is possible to increase the mechanical strength of the electrolyte membrane and more effectively prevent the liquid electrolyte from exuding from the electrolyte membrane.

  When the electrolyte membrane 10 has three layers, as shown in FIG. 1B, the first layer 1 a and the first layer 1 b are respectively disposed in the outermost layers of the electrolyte membrane 10. That is, the first layer 1 a and the first layer 1 b are respectively disposed on both main surfaces of the second layer 2. Further, even when the electrolyte membrane 10 has five layers, as shown in FIG. 1C, the first layer 1 a and the first layer 1 b are respectively disposed on the outermost layers of the electrolyte membrane 10. Specifically, as shown in FIG. 1C, the first layer 1a, the second layer 2a, the first layer 1c, the second layer 2b, and the first layer 1b are arranged in order. Also good. In this way, by disposing the first layer containing the solid acid as the outermost layer of the electrolyte membrane 10 and arranging the second layer containing the liquid electrolyte between the first layers, that is, the inner layer of the electrolyte membrane 10. Thus, an electrolyte membrane having excellent mechanical strength and good ionic conductivity in a non-humidified state while preventing the liquid electrolyte from exuding from the electrolyte membrane can be obtained.

  In the above, the content and type of the solid acid in the first layer 1a, the first layer 1b, and the first layer 1c may be the same or different. Further, the content and type of the liquid electrolyte in the second layer 2a and the second layer 2b may be the same or different. And when the 2nd layer 2a and the 2nd layer 2b contain a solid acid, the kind and content of a solid acid may be the same, and may differ.

  1A to 1C exemplify two-layer, three-layer, and five-layer electrolyte membranes, the electrolyte membrane of the present invention is not limited to the above-described electrolyte membrane. When the electrolyte membrane has three or more layers, the first layer containing a solid acid is preferably disposed in the outermost layer on both sides of the electrolyte membrane, and a liquid electrolyte is interposed between the two first layers. One or a plurality of second layers may be arranged. In addition to the second layer, one or more first layers may be arranged between the two first layers.

  Although content of the solid acid in the 1st layer 1 is not specifically limited, From a viewpoint of improving mechanical strength and ion conductivity, it is preferable that it is 20-100 weight%, and it is 50-100 weight%. Further preferred.

  The content of the liquid electrolyte in the second layer 2 is not particularly limited, but it is preferably 10 to 90% by weight, and preferably 20 to 80% by weight from the viewpoint of increasing mechanical strength and ion conductivity. Further preferred. Further, the content of the solid acid in the second layer 2 is not particularly limited, but is preferably 10 to 90% by weight, and preferably 15 to 85% by weight from the viewpoint of increasing mechanical strength and ion conductivity. More preferably.

1A to 1C exemplify an electrolyte membrane in which each layer is clearly divided, but the boundary of each layer may not be clearly divided, and a liquid electrolyte is formed in the thickness direction of the electrolyte membrane. It is only necessary to have a portion containing a solid acid and a portion containing a solid acid. The layer structure of the electrolyte membrane 10 and the contents of the liquid electrolyte and the solid acid can be confirmed as follows, for example.
(1) The electrolyte membrane is cut in the thickness direction, and SEM (scanning electron microscope) observation is performed on the cross section.
(2) The electrolyte membrane is cut in the thickness direction, and EDX measurement (measurement by an energy dispersive X-ray analyzer) is performed on the cross section to confirm the concentration distribution of the specific element.
(3) The specific element in the thickness direction of the electrolyte membrane is analyzed by glow discharge emission analysis.
(4) The electrolyte membrane is cut obliquely and XPS analysis (X-ray photoelectron spectroscopy) of the shaved surface is performed.

  The thickness of the electrolyte membrane 10 is not particularly limited, but is usually about 10 to 1000 μm, and preferably about 30 to 300 μm from the viewpoint of mechanical strength. The thickness of the first layer 1 is not limited, but is usually about 5 to 1000 μm, and preferably about 10 to 300 μm from the viewpoint of mechanical strength. The thickness of the second layer 2 is not limited, but is usually about 5 to 1000 μm, and preferably about 10 to 300 μm from the viewpoint of mechanical strength.

<Solid acid>
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. Here, 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 solid 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. Specific examples of the metal phosphate include orthophosphates and pyrophosphates such as tin, zirconium, cesium, and tungsten.

  As the pyrophosphate, a metal phosphate represented by the following general formula (1) is preferably used from the viewpoint of excellent proton conductivity.

[Chemical 1]
M _1-x D _x P ₂ O ₇ (1)

  However, in the general formula (1), X is 0 ≦ X <0.5, and M (main metal) is Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na And D (doped metal) is a kind selected from the group consisting of Al, In, B, Ga, Sc, Yb, Ce, La, Sb, Y, Nb and Mg. .

  The metal phosphate represented by the general formula (1) includes Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na, or Al as the main metal, Pyrophosphates doped with different metals are preferred. When a doped metal is used, it is preferable to use Sn, Cs, Ti, or Zr as the main metal from the viewpoint of stability as a phosphate. More preferably, it is a pyrophosphate in which a part of a metal such as tin or cesium is doped (substituted) with a doped metal element such as indium, aluminum or antimony.

  As the doped metal, for example, when Sn is used as the main metal, In, Al, and the like are preferable 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. However, 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: 3-9.8: 0.2. A range of is desirable.

  The metal phosphate represented by the general formula (1) can be synthesized, for example, by heating one or more metal oxides and phosphoric acid and performing 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 of Zr, Cs, Sn, Ti, Si, Ge, Pb, Hf, Ca, Mg, W, Na, and Al. As the phosphoric acid, either liquid phosphoric acid or solid phosphoric acid may be used. From the viewpoint of avoiding the problem of loss of phosphoric acid during heat treatment, it is preferable to use solid phosphoric acid. As solid phosphoric acid, for example, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate and the like can be used.

  Specifically, the metal phosphate represented by the general formula (1) can be produced as follows. First, a compound containing a main metal such as tin (hereinafter simply referred to as a main metal compound) and a compound containing a doped metal such as indium (hereinafter also simply referred to as a doped metal compound) and liquid phosphoric acid are mixed. A mixture is obtained. 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 100 to 300 ° C. for 1 to 3 hours to obtain a dispersion. The obtained dispersion is put in a crucible and baked at a temperature of 300 to 700 ° C. for 1 to 3 hours, for example. Since phosphoric acid may be lost in the high temperature state, it is desirable to add the liquid phosphoric acid in excess, for example, 1.1 to 1.5 times the molar equivalent. In addition, as a main metal compound and dope metal compound, a metal oxide, a metal hydroxide, a metal chloride, a metal nitrate etc. can be used, for example.

  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, using ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, etc., a metal oxide containing a main metal such as tin and a metal oxide containing a doped metal such as indium and a predetermined number of moles. Mix with. The metal oxide containing the main metal and the metal oxide containing the doped metal are preferably mixed at a molar ratio of the main metal to the doped metal of, for example, 9: 1 to 1: 1. The obtained mixture is put into a crucible and baked at a temperature of 300 to 650 ° C. for 1 to 3 hours, for example. The resulting product can then be ground in an agate bowl to give the desired metal phosphate. By using solid phosphoric acid, a molar equivalent of phosphoric acid reacts with the metal oxide, and the surplus material volatilizes at a high temperature, so that surplus phosphoric acid does not adhere and a reproducible metal phosphate can be obtained. .

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 a 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 sucked and filtered to dry, the dried precipitate and phosphoric acid are mixed, and heat treatment is performed at about 200 ° C. for about 2 hours in a reducing atmosphere to obtain a metal phosphate. . Finally, wash with deionized water. According to the coprecipitation method, a metal phosphate in which a doped metal is uniformly doped into a main metal phosphate is prepared by simultaneously precipitating a plurality of types of hardly soluble salts from a solution containing a plurality of desired metal ions. be able to.

  The solid acid may be an electrolyte composed of a metal phosphate represented by the general formula (1) and phosphoric acids.

  In the electrolyte composed of the metal phosphate represented by the general formula (1) and phosphoric acids, the number of atoms of the metal element of the metal phosphate and the metal element to be doped is [m] and [n], respectively. When the sum of the number of phosphorus atoms in the metal phosphate and the number of phosphorus atoms in phosphoric acid is [p], it is preferable to satisfy the following formula (1).

[Equation 1]
2 <[p] / ([m] + [n]) ≦ 4 (1)

  More preferably, the following mathematical formula (2) is satisfied.

[Equation 2]
2.4 ≦ [p] / ([m] + [n]) ≦ 3.2 (2)

  By satisfy | filling the said Numerical formula (1), while high proton conductivity is obtained, a moldability will become favorable. When the value of the mathematical formula [p] / ([m] + [n]) is 2 or less, the amount of phosphoric acid on the metal phosphate is decreased, and proton conductivity may not be improved. On the other hand, when the value of the above formula [p] / ([m] + [n]) exceeds 4, the amount of phosphoric acid is too large, moisture absorption in the atmosphere is high, and the molded body becomes brittle, so that the shape is maintained. There is a fear that it cannot be done.

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. 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. Examples of the heteropolyacid include tungsten phosphoric acid (H ₃ PW ₁₂ O ₄₀ : WPA). From the viewpoint of proton conductivity, the complex of heteropolyacid and inorganic salt is preferably a complex of hydrogensulfate and heteropolyacid, more preferably a complex of potassium hydrogensulfate and tungsten phosphate obtained by a mechanochemical method. Is the body.

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 5 to 24 hours to form 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 hydrogensulfate 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 a complex of tungsten phosphoric acid and potassium hydrogen sulfate is produced by the above mechanochemical method, it is relatively easy to produce because a high-temperature process is not required as in the production of metal phosphate. There is an advantage.

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, cesium phosphoric acid, silicon phosphate (SiP ₂ O ₇ ), or 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. In addition, cesium phosphate, silicon phosphate, and a composite thereof are, for example, “Toshiaki Matsui, Tomokazu Kukino, Ryuji Kikuchi, and Koichi Eguchi, The2 A3, A3, A3” “Toshiaki Matsui, Tomokazu Kukino, Ryuji Kikuchi, and koichi Eguchi, Electrochemical Acta 51 (2006) 3719-3723” 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 and stirred with a stir bar using a stirrer or the like. Subsequently, liquid phosphoric acid is dripped little by little, and water is evaporated, stirring at the temperature of 100-150 degreeC for 1-3 hours. Then, it puts into oven and is dried at the temperature of 100-150 degreeC, for example. The drying time is, for example, 1 day to several days. Next, the obtained product is pulverized in an agate bowl into a powder form to obtain the desired cesium dihydrogen phosphate (CsH ₂ PO ₄ ) or cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ). Can do.

Next, silicon phosphate (SiP ₂ O ₇ ) is produced as follows. A mixture of silicon dioxide (SiO ₂ ) and liquid phosphoric acid is placed in an agate noodle and mixed until it becomes a starch candy, then placed in an alumina crucible and baked at a temperature of 100 to 700 ° C. The firing time is, for example, 30 to 80 hours. Then, the obtained product 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 is dispersed by a pod mill, a ball 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 ) A composite of ₂ ) and silicon phosphate (SiP ₂ O ₇ ) is obtained. The dispersion time is, for example, 1 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 molar ratio.

In addition, as the solid acid, potassium phosphate, silicon phosphate (SiP ₂ O ₇ ), or a complex of potassium phosphate and silicon phosphate (SiP ₂ O ₇ ) may be used. Examples of the potassium phosphoric acid include potassium dihydrogen phosphate (KH ₂ PO ₄ ) and potassium pentahydrogen diphosphate (KH ₅ (PO ₄ ) ₂ ). Complex of potassium dihydrogen phosphate (KH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) or complex of potassium dihydrogen phosphate (KH ₅ (PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) The bodies are cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ), respectively, except that potassium carbonate (K ₂ CO ₃ ) is used instead of cesium carbonate (Cs ₂ CO ₃ ). ) Or a complex of cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ) and silicon phosphate (SiP ₂ O ₇ ).

  Since the organic solid acid dissolves in the solvent, the compatibility with the binder component is good, and the dispersibility becomes good at the time of preparing the electrolyte composition, so that 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 0.1-200 micrometers in an electrolyte membrane, Preferably it is 0.1-150 micrometers. The solid acid as a raw material before forming the electrolyte membrane also has a particle size of 0.1 to 200 μm, preferably 0.1 to 150 μm. When the particle size of the solid acid is 0.1 to 200 μm, the dispersibility at the time of preparing the electrolyte composition 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.

<Liquid electrolyte>
As the liquid electrolyte, a liquid electrolyte having ion conductivity can be used even in a temperature range from room temperature to 200 ° C. and in a non-humidified atmosphere. In the present invention, the non-humidified atmosphere means that intentional humidification is not performed in the atmosphere where the liquid electrolyte is placed.

  The liquid electrolyte contained in the second layer 2 may be one type or a combination of two or more types.

  As the liquid electrolyte, for example, a strong acid, an ionic liquid, or the like can be used.

Examples of strong acids include inorganic acids such as phosphoric acids and sulfuric acid. Phosphoric acids (hereinafter also simply referred to as “phosphoric acid”) refer to orthophosphoric acid and phosphoric acid condensates, and examples of phosphoric acid condensates include pyrophosphoric acid, triphosphoric acid, metaphosphoric acid (polyphosphoric acid), and the like. . When using the phosphoric acid as a strong acid, ion conductivity, density, from the viewpoint of handling property, a concentration of about 85 to 122 weight% of phosphoric acid (H ₃ PO ₄₎ is preferably used an aqueous solution.

  In the present invention, the ionic liquid is also referred to as a room temperature molten salt, and means a liquid that is in a liquid state at room temperature (20 ± 15 ° C.) among melts composed only of ions. The ionic liquid is composed of a cation component and an anion component.

  The cation component of the ionic liquid is not particularly limited, and examples thereof include imidazolium derivatives, pyridinium derivatives, pyrrolidinium derivatives, ammonium derivatives, those having a nitrogen-containing heterocyclic ring, guanidinium derivatives, and isouronium derivatives. Among them, from the viewpoint of heat resistance, conductivity, etc., it is preferably at least one selected from the group consisting of imidazolium derivatives and ammonium derivatives, such as imidazolium cation, 2-ethylimidazolium cation, 1-methyl-3-methyl. More preferably, it is at least one selected from the group consisting of an imidazolium cation, a 1-ethyl-3-methylimidazolium cation and a diethylmethylammonium cation.

The anion component of the ionic liquid is not particularly limited. For example, sulfates, sulfonic acids, amides, imides, methanes, halogens, boron-containing anions, phosphates, antimony, hydrofluoride anion, fluorine System anions, thiocyanates and the like. Among these, from the viewpoint of heat resistance, conductivity, etc., it is preferably at least one selected from the group consisting of sulfates, imides and thiocyanates, [CF ₃ SO ₃ ] ⁻ , [(FSO ₂ ) ₂ N] ^- and [SCN] ^- it is more preferably one or more selected from the group consisting of. From the viewpoint of excellent ion conductivity, the anion components are [CF ₃ SO ₃ ] ⁻ , [(FSO ₂ ) ₂ N] ⁻ , [SCN] ⁻ , [HSO ₄ ] ⁻ and bis (trifluoromethanesulfonyl) amide (bis). (Trifluoromethanesulfonyl) amide, also referred to as HTFSI in the following) is preferably one or more selected from the group consisting of [CF ₃ SO ₃ ] ⁻ , [HSO ₄ ] ⁻ and HTFSI. More preferably.

  In the present invention, the ionic liquid preferably contains protic ions. In the present invention, “protic ion” means an ion having proton accepting property and / or proton donating property.

The protic ion is not particularly limited, and examples thereof include proton monohydrogen sulfate ion (HSO ₄ ⁻ ), monohydrogen phosphate ion (HPO ₄ ²⁻ ), dihydrogen phosphate ion (H ₂ PO ₄ ⁻ ), and selenium. Acid monohydrogen ion (HSeO ₄ ⁻ ), pyrohydrogen monohydrogen ion (HP ₂ O ₇ ³⁻ ), dihydrogen pyrophosphate ion (H ₂ P ₂ O ₇ ²⁻ ), trihydrogen pyrophosphate ion (H ₃ P ₂₎ O ₇ ⁻ ), phosphonate monohydrogen ion (H ₂ PO ₃ ⁻ ) and the like.

  The ionic liquid may contain one or more of the above-described cation components. Further, the ionic liquid may contain one or more of the above-mentioned anion components.

  The ionic liquid can be obtained by a known method (for example, see J. AM. CHEM. SOC. 2010, 132, pages 964-9773, etc.). In the present invention, an ionic liquid produced by a known method may be used, or a commercially available product may be used. Examples of commercially available products include 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (1-Ethyl-3-methylimidazolium bis (fluorosulfonyl) imide) manufactured by Mitsubishi Materials Corporation, and 1- 1 manufactured by Merck & Co., Inc. 1-Ethyl-3-methylimidazolium triflate, 1-ethyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-methyl imidazole, 1-ethyl-3-methylimidazolium triflate (1-Ethyl-3-methylimidazolium triflate), 1-Ethyl-3-methylimidazolium hydrogen sulfate (1-Ethyl-3-methylimidazolium hydrogensulfate) Lithium thiocyanate (1-Ethyl-3-methylimidazolium thiocynate) or the like can be used. . Alternatively, an ionic liquid obtained by mixing a commercially available cation component and an anion component, for example, imidazolium bis obtained by mixing imidazole manufactured by Tokyo Chemical Industry Co., Ltd. and HTFSI manufactured by Wako Pure Chemical Industries, Ltd. (Trifluoromethanesulfonyl) amide, 2-ethylimidazole manufactured by Tokyo Chemical Industry Co., Ltd., and imidazolium bis (trifluoromethanesulfonyl) amide obtained by mixing HTFSI manufactured by Wako Pure Chemical Industries, Ltd. It may be used.

<Binder>
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 epoxy resin, an acrylic resin, or the like is used. Can do. Especially, what has the acid resistance in the range of pH 1-3 and the heat resistance in the temperature range of 50-300 degreeC is preferable. Moreover, you may have ion conductivity.

  Although it does not specifically limit as said fluorine-type polymer, For example, tetrafluoroethylene (PTFE), a polyvinylidene fluoride, a fluoroethylene-hexafluoropropylene copolymer (FEP), a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer A fluororesin such as (PFA) 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 Benzooxazole, polyoxadiazol, polyxylone, polyquinoxaline, polythiadiazol, polytetrazavilen, polyoxazole, polythiazole, polyvinyl pyridine, polyvinyl imidazole, and the like can be used.

  The fluorine ionomer is not particularly limited. For example, a perfluorosulfonic acid type such as Nafion (registered trademark) of DuPont, Flemion (registered trademark) of Asahi Glass Co., and Aciplex (registered trademark) of Asahi Kasei Co., Ltd., Aquivion A sulfonyl fluoride vinyl ether (SFVE) -tetrafluoroethylene copolymer such as (registered trademark) can be used.

  The hydrocarbon ionomer is not particularly limited. For example, polyarylene ether sulfonic acid, polystyrene sulfonic acid, syndiotactic polystyrene sulfonic acid, polyphenylene ether sulfonic acid, modified polyphenylene ether sulfonic acid, polyether sulfonic acid, polyether ether. Ketone sulfonic acid and polyphenylene sulfide sulfonic acid can be used.

  As the epoxy resin, bisphenol A type epoxy resin, novolac type phenol resin, or the like can be used. Also, a hybrid resin of the above resin and silica can be used.

  As the acrylic resin, polymethyl methacrylate, polystyrene, or the like can be used. Also, a hybrid resin of the above resin and silica can be used.

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

  Among the above-mentioned binders, PTFE, polyvinylidene fluoride, perfluorosulfonic acid, cellulose acetate, sulfonyl fluoride vinyl ether (SFVE) -tetrafluoroethylene copolymer, polyether ether ketone sulfone from the viewpoint of durability and binding properties. An acid is preferably used. The polyether ether ketone sulfonic acid is not particularly limited. L. Those synthesized by the method described in Di Vona et al, Polymer 46 (2005), pages 1754-1758 can be used.

  Only one type of binder described above may be used, or two or more types may be used in appropriate combination.

  Hereinafter, a method for manufacturing the electrolyte membrane will be described.

(Method for manufacturing electrolyte membrane)
The electrolyte membrane 10 of the present invention is not particularly limited, but can be manufactured as follows, for example. The electrolyte membrane 10 forms the 1st layer 1 using the electrolyte composition containing a solid acid, forms the 2nd layer 2 using the electrolyte composition containing a liquid electrolyte, and the 1st layer 1 is electrolyte. It is obtained by laminating the first layer 1 and the second layer 2 so as to be disposed on the outermost layer on one side or both sides of the film 10.

<First Layer-Forming Electrolyte Composition>
The first layer 1 can be formed using the first layer-forming electrolyte composition. The first layer-forming electrolyte composition contains a solid acid. What is necessary is just to use the above-mentioned solid acid.

  When the first layer 1 does not contain a binder, the solid acid can be used as it is as the first layer-forming electrolyte composition, or the first layer-forming electrolyte composition can be obtained by dispersing the solid acid in a solvent. It may be used as When the 1st layer 1 contains a binder, the electrolyte composition for 1st layer formation can be produced by mixing a solid acid and a binder. Alternatively, the first layer-forming electrolyte composition may be prepared by adding a solid acid to a binder solution or binder dispersion and then adding a solvent. As the solvent, a solvent that does not aggregate the binder can be used. Specifically, water, ethanol, methanol, 1-butanol, t-butanol, propanol, N-methylpyrrolidone, dimethylacetamide and the like can be used.

  The first layer-forming electrolyte composition is preferably mixed and dispersed by a disperser. As the disperser, for example, an ultrasonic disperser, a homogenizer, a planetary ball mill, a ball mill dispersion, a stirrer dispersion, or the like can be used.

  In the first layer-forming electrolyte composition, the solid acid content is preferably 20 to 100% by weight, and more preferably 50 to 100% by weight. If the ratio of the solid acid in the first layer-forming electrolyte composition is less than 20% by weight, the ion conductivity may be poor. Further, from the viewpoint of improving moldability while maintaining excellent ion conductivity, the binder content in the first layer-forming electrolyte composition is preferably 60% by weight or less, and 50% by weight. More preferably, it is as follows. In the present invention, the content of each composition in the first layer forming electrolyte composition refers to the ratio of the weight of each composition to the solid content of the first layer forming electrolyte composition. In the present invention, the weight of the binder refers to the weight of the solid content of the binder.

<Second Layer Forming Electrolyte Composition>
The second layer 2 can be formed using the second layer forming electrolyte composition. The second layer forming electrolyte composition contains a liquid electrolyte. When the second layer 2 contains neither a binder nor a solid acid, the liquid electrolyte can be used as it is as the second layer forming electrolyte composition. When the second layer 2 contains a binder and / or a solid acid, the second layer is formed using the second layer-forming electrolyte composition prepared by mixing the liquid electrolyte and the solid acid and / or the binder. Can be formed. As the liquid electrolyte, binder, and solid acid, those described above can be used. The second layer forming electrolyte composition can be produced by the same method as the first layer forming electrolyte composition.

  From the viewpoint of increasing the mechanical strength and ionic conductivity of the electrolyte membrane, the content of the liquid electrolyte in the second layer forming electrolyte composition is preferably 10 to 90% by weight, and preferably 20 to 80% by weight. More preferably. Further, from the viewpoint of increasing the mechanical strength and ionic conductivity of the electrolyte membrane, the content of the solid acid in the second layer forming electrolyte composition is preferably 10 to 90% by weight, and 15 to 85% by weight. % Is more preferable. From the viewpoint of improving moldability while maintaining excellent ion conductivity, the binder content in the second layer-forming electrolyte composition is preferably 60% by weight or less, and preferably 50% by weight or less. More preferably. In the present invention, the content of each composition in the second layer forming electrolyte composition refers to the ratio of the weight of each composition to the solid content of the second layer forming electrolyte composition and the total weight of the liquid electrolyte.

<Preparation of electrolyte membrane>
The production of the electrolyte membrane is not particularly limited, but can be performed as follows, for example.

(1) First, the first layer-forming electrolyte composition is applied to a substrate and dried to form the first layer. Next, the second layer-forming electrolyte composition is applied on the main surface of the first layer formed on the substrate, and dried to form the second layer. The first layer and the second layer Laminate the layers. Alternatively, if necessary, after laminating the first layer and the second layer as described above, the first layer-forming electrolyte composition is further applied onto the main surface of the second layer and dried. The first layer is formed on both main surfaces of the second layer.
(2) First, the second layer-forming electrolyte composition is applied to a substrate and dried to form a second layer. Next, the first layer-forming electrolyte composition is applied onto the main surface of the second layer formed on the substrate, and dried to form the first layer. The first layer and the second layer Laminate the layers. Or after peeling a base material from the 2nd layer formed on the base material as needed, the electrolyte composition for 1st layer formation is apply | coated on both main surfaces of a 2nd layer, and it dries. Thus, the first layer is formed on both main surfaces of the second layer.
(3) First, the first layer-forming electrolyte composition and the second layer-forming electrolyte composition are each applied to a substrate and dried to form a first layer and a second layer. Next, the first layer formed on the substrate and the second layer formed on the substrate are laminated so that the first layer is disposed on the outermost layer on one side or both sides of the electrolyte membrane.
(4) The first layer-forming electrolyte composition is uniaxially pressed to produce pellets, the first layer is formed, the second layer-forming electrolyte composition is applied to a substrate, dried, and then dried. After forming the two layers, the first layer and the second layer are laminated so that the first layer is disposed on the outermost layer on one side or both sides of the electrolyte membrane.
(5) First, the second layer forming electrolyte composition is applied to a substrate and dried to form a second layer. Next, the first layer-forming electrolyte composition is disposed on the main surface of the second layer, the solid acid is melted and then cooled and solidified to form the first layer. The first layer and the second layer are laminated so as to be disposed on the outermost layer on one side or both sides of the electrolyte membrane.
In any of the above cases, the substrate may be peeled off appropriately before and after the first layer and the second layer are laminated.

  The method for applying the electrolyte composition is not particularly limited, and examples thereof include knife coaters, bar coaters, spray coating, dip coaters, spin coaters, roll coaters, die coaters, curtain coaters, screen printing, and rolling methods. Can be applied.

  Drying can be performed by heat treatment. The heat treatment temperature (drying temperature) is preferably about 50 to 300 ° C, more preferably 90 to 200 ° C. If the heat treatment temperature is lower than about 50 ° C., the solvent contained in the electrolyte composition may not be removed, and if it exceeds about 300 ° C., the binder or the liquid electrolyte may be thermally decomposed. The heat treatment time (drying time) is preferably about 10 minutes to 5 hours, more preferably about 10 minutes to 3 hours.

  As the substrate, for example, a polymer film, coated paper, non-coated paper or the like can be used. Examples of the polymer film include polyimide, polyethylene terephthalate, polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyetherimide, polyarylate, polyethylene naphthalate (PET). A polymer film composed of, for example, can be used. Further, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. A polymer film made of a conductive fluororesin may be used. As the coated paper, for example, art paper, coated paper, lightweight coated paper or the like can be used, and as the non-coated paper, for example, notebook paper, copy paper or the like can be used. Among these, a polymer film that is inexpensive and easily available is preferable, and a PET film is more preferable.

  Moreover, as a base material, an electrode with a catalyst layer and a catalyst transfer film can also be used. In this case, the electrolyte composition may be applied to the catalyst layer side.

  Lamination | stacking of the 1st layer 1 and the 2nd layer 2 which were formed separately can be performed by overlapping so that the main surface of the 1st layer 1 and the main surface of the 2nd layer 2 may contact | connect, for example. Moreover, after superimposing so that the main surface of the 1st layer 1 and the main surface of the 2nd layer 2 may contact, you may perform press, such as a hot press and a pressure press. In addition, although a press is not specifically limited, It is preferable to carry out on conditions with a temperature of -10-300 degreeC and a pressure of 0.1-30 MPa.

  Although the uniaxial press of the electrolyte composition for 1st layer formation is not specifically limited, For example, it is preferable to carry out at 0.1-30 Mpa, and it is more preferable to carry out at 0.5-5 Mpa.

  The melting of the first layer-forming electrolyte composition may be performed at a temperature equal to or higher than the melting point of the solid acid, and is not particularly limited. It is more preferable to carry out at a temperature higher by at least ° C. The treatment time is about 5 minutes to 5 hours, preferably about 10 minutes to 3 hours. Further, the cooling temperature may be appropriately determined within the range below the melting point of the solid acid. For example, the cooling temperature is less than about 140 ° C., preferably about room temperature to about 100 ° C. The cooling time is about 5 minutes to 5 hours, preferably about 10 minutes to 3 hours.

  The substrate may be peeled by a normal method, and is not particularly limited. For example, the substrate can be peeled by 180 degrees.

  As described above, the first layer is formed using the electrolyte composition containing the solid acid, the second layer is formed using the electrolyte composition containing the liquid electrolyte, and the first layer is on one side of the electrolyte membrane. Alternatively, by laminating the first layer and the second layer so as to be disposed on the outermost layers on both sides, the mechanical strength is excellent, and there is good ionic conductivity in a non-humidified state. An electrolyte membrane in which the liquid electrolyte is prevented from seeping out is obtained.

[Embodiment 2]
Hereinafter, a catalyst layer-electrolyte membrane laminate will be described as Embodiment 2 of the present invention.

(Catalyst layer-electrolyte membrane laminate)
FIG. 2 is a schematic cross-sectional view showing an example of a catalyst layer-electrolyte membrane laminate according to Embodiment 2 of the present invention. As shown in FIG. 2, the catalyst layer-electrolyte membrane laminate 20 includes an electrolyte membrane 10 and a pair of catalyst layers 6 and 7, and the catalyst layers 6 and 7 are respectively formed on both main surfaces of the electrolyte membrane 10. Has been placed. In FIG. 2, the same parts as those in FIG. 2 and 1 have the same function.

  The catalyst layers 6 and 7 may be layers containing a catalyst, and are not particularly limited. However, from the viewpoint of increasing the reaction field, it is preferable that the catalyst layers 6 and 7 further include the liquid electrolyte shown in the first embodiment. The liquid electrolyte can be included in the catalyst layer by preparing the catalyst layer using a catalyst paste containing the liquid electrolyte. Or you may make a catalyst layer contain a liquid electrolyte by apply | coating and impregnating a liquid electrolyte to the catalyst layer which does not contain a liquid electrolyte. The liquid electrolyte is preferably contained in such an amount that does not block the pores of the catalyst layer.

  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 .; platinum black, platinum-ruthenium black, platinum-cobalt Examples thereof include metal fine particles such as black, gold black and silver black; 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 6 and 7 may further contain a binder. The catalyst layers 6 and 7 can be formed by using only a catalyst, but a catalyst layer having excellent mechanical strength can be obtained by coating and molding a paste obtained by adding a binder. . As the binder, for example, the binder shown in Embodiment 1 can be used.

  The thicknesses of the catalyst layers 6 and 7 may be appropriately determined in consideration of the type of electrode base material, the thickness of the electrolyte membrane, and the like. The thickness of the catalyst layers 6 and 7 is about 20-3000 micrometers, for example, Preferably, it is about 30-2000 micrometers.

  The catalyst layer-electrolyte membrane laminate 20 can be produced, for example, by forming the catalyst layers 6 and 7 by applying a catalyst paste containing a catalyst onto both main surfaces of the electrolyte membrane 10 and drying. In addition, although not particularly limited, since the liquid electrolyte tends to flow to the catalyst layer simultaneously with the water generated from the cathode when there is a large amount of liquid electrolyte on the cathode side, the first layer 1 in the electrolyte membrane 10 is set to the cathode side. Is preferred.

  The catalyst paste is obtained, for example, by mixing and dispersing a mixture containing a catalyst, a liquid electrolyte, and a solvent with a disperser. As the disperser, an ultrasonic disperser, a homogenizer, a ball mill, or the like can be used. When the catalyst paste contains a binder, the amount of the binder (solid content) added is preferably 50% by weight or less, and 40% by weight or less based on the total weight of the solid content and the liquid electrolyte in the catalyst paste. More preferably. In this case, the catalyst paste and the liquid electrolyte may be added to a binder solution or dispersion, and then a solvent may be added to produce a catalyst paste. As the solvent, a solvent that does not aggregate the binder can be used. Specifically, water, ethanol, methanol, 1-butanol, t-butanol, propanol, N-methylpyrrolidone, dimethylacetamide and the like can be used.

As the coating amount of the catalyst paste, for example, when platinum-supported carbon is used, the platinum-supported amount is preferably about 0.1 to 1.0 mg / cm ² , more preferably about 0.3 to 0.6 mg / cm ^2. it is cm ^2.

The method of applying the catalyst paste on the electrolyte membrane 10 is not particularly limited, and for example,
Screen printing, blade coating, die coating, spray coating, dispenser coating, inkjet coating, and the like can be used. Of these, it is preferable to use screen printing or blade coating because of the ease of preparation of the catalyst paste.

  Drying can be performed by heat treatment, for example. The heat treatment temperature (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 liquid electrolyte and 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.

  According to the present embodiment, there is provided a catalyst layer-electrolyte membrane laminate that has excellent mechanical strength, has good ionic conductivity in a non-humidified state, and prevents the liquid electrolyte from exuding from the electrolyte membrane. be able to.

[Embodiment 3]
Hereinafter, a membrane electrode assembly will be described as Embodiment 3 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 3 of the present invention. As shown in FIG. 3, the membrane electrode assembly 30 according to Embodiment 3 of the present invention includes the electrolyte membrane 10 shown in Embodiment 1 and a pair of catalyst electrodes 16 and 17. The electrolyte membrane 10 is disposed on both main surfaces. In FIG. 3, the same parts as those in FIG. 3 and FIG. 1 have the same functions.

  The catalyst electrodes 16 and 17 are made of a conductive material having gas diffusibility, such as a catalyst and a porous body, so that fuel gas or oxidant gas can flow therethrough. The anode electrode side catalyst electrode 17 is a fuel electrode, and the cathode electrode side catalyst electrode 16 is an oxidant electrode. A catalytic metal that promotes an oxidation reaction of hydrogen is attached to the fuel electrode, and a catalytic metal that promotes a reduction reaction of oxygen is attached to the oxidant electrode.

  The thickness of the catalyst electrodes 16 and 17 may be appropriately determined in consideration of the type of electrode base material, the thickness of the electrolyte membrane, and the like. The thickness of the catalyst electrodes 16 and 17 is, for example, about 20 to 3000 μm, and preferably about 30 to 2000 μm.

  The catalyst electrodes 16 and 17 may be composed of two layers, a gas diffusion layer and a catalyst layer. As the gas diffusion layer, a known material such as carbon paper, carbon cloth, or carbon felt may be used. Moreover, you may use what performed the water-repellent process to said well-known material. Further, a gas diffusion layer provided with a flattening layer may be used in order to prevent penetration when a catalyst paste is applied to the gas diffusion layer.

  The membrane electrode assembly 30 according to the present embodiment can be manufactured by using the electrolyte membrane 10 shown in the first embodiment and forming the catalyst electrodes 16 and 17 on both main surfaces thereof by pressure bonding or the like. Although not particularly limited, since the liquid electrolyte tends to flow to the catalyst layer simultaneously with the water generated from the cathode if there is a large amount of liquid electrolyte on the cathode side, the first layer in the electrolyte membrane 10 is made the cathode side. Is preferred.

  According to the present embodiment, it is possible to provide a membrane electrode assembly that has excellent mechanical strength, has good ionic conductivity in a non-humidified state, and prevents the liquid electrolyte from exuding from the electrolyte membrane. .

[Embodiment 4]
Hereinafter, a fuel cell will be described as Embodiment 4 of the present invention.

(Fuel cell)
FIG. 4 is a schematic cross-sectional view showing an example of a fuel cell according to Embodiment 4 of the present invention. As shown in FIG. 4, the fuel cell 40 according to Embodiment 4 of the present invention includes the electrolyte membrane 10 shown in Embodiment 1, the pair of catalyst electrodes 16 and 17 shown in Embodiment 3, and the pair of separators 28. 29, and catalyst electrodes 16 and 17 and separators 28 and 29 are laminated in this order on both main surfaces of the electrolyte membrane 10, respectively. 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 17, 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 16 and has an oxidant gas flow path 22 for circulating the oxidant gas.

  The material of the separators 28 and 29 may be any material having stable conductivity even in the environment inside the fuel cell 40. In general, a carbon plate having a flow path is used. Further, the separators 28 and 29 are made of a metal such as stainless steel, and a film made of a conductive material such as chromium, a platinum group metal, an oxide of a platinum group metal, or a conductive polymer is formed on the surface of the metal. It may be.

  The separators 28 and 29 can function as a current collector when used in a fuel cell in which a plurality of fuel cells 40 are stacked.

(Fuel cell operating principle)
A fuel capable of supplying hydrogen, such as hydrogen gas or methanol, is supplied to the anode-side catalyst electrode 17 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 16 by the electrolyte membrane 10. On the other hand, an oxidant gas such as air or oxygen gas is supplied to the cathode side catalyst electrode 16 through the oxidant gas flow path 22, and protons carried by the electrolyte membrane 10 and electrons and oxidant gas coming from the external circuit 23. Reacts to produce water. In this way, it functions as a fuel cell.

  In the fuel cell 40 according to the present embodiment, the catalyst electrodes 16 and 17 and the separators 28 and 29 are laminated in this order on both main surfaces of the electrolyte membrane 10 by using a known technique used for manufacturing a fuel cell. Can be manufactured.

  According to the present embodiment, by using an electrolyte membrane that is excellent in mechanical strength, has good ionic conductivity in a non-humidified state, and prevents leakage of the liquid electrolyte from the electrolyte membrane, stability is achieved. An excellent and high-performance fuel cell 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

<Solid acid>
As the solid acid, silicon phosphate (SiP ₂ O ₇ ) prepared as follows was used. Silicon dioxide (SiO ₂ ) and liquid phosphoric acid are blended at a molar ratio of 1: 2.5, and the resulting mixture is placed in an agate noodle and mixed until it becomes a starch candy, then put in an alumina crucible and dried. And calcining at about 700 ° C. for 3 hours. After firing, the obtained product was pulverized in an agate bowl to obtain silicon phosphate (SiP ₂ O ₇ ).

As a liquid electrolyte is the ionic liquid 1-ethyl-3-methylimidazolium hydrogen sulphate ^- was used (manufactured by Merck Co., EMIm-HSO ₄ below and also referred.). As a binder, M.I. L. A sulfonated polyetheretherketone (hereinafter also referred to as SPEEK) synthesized as described below based on the method described in Di Vona et al, Polymer 46 (2005), pages 1754-1758 was used.

<Binder Production Example 1>
A 500 ml round bottom flask equipped with a reflux condenser was charged with 5 g of polyetheretherketone (manufactured by VICTREX, also referred to as PEEK in the following) and 250 ml of 96 wt% concentrated sulfuric acid, and kept at 50 ° C. in an oil bath. The mixture was refluxed for 18 hours with stirring. Thereafter, the reaction mixture was filtered through a glass filter, and the solid matter collected by filtration was washed with pure water. Washing was repeated until the filtrate was close to neutral, and then the solid was dried at 50 ° C. for 24 hours and then vacuum dried at 60 ° C. for 6 hours to obtain SPEEK.

  1 g of the obtained SPEEK and 20 g of DMA (N′N-dimethylacetamide) were mixed, kept at 50 ° C. in an oil bath, and stirred for 24 hours to prepare a SPEEK solution.

<First Layer-Forming Electrolyte Composition>
20 g of the SPEEK solution obtained above and 9 g of silicon phosphate (SiP ₂ O ₇ ) obtained above were mixed and dispersed with a disperser to produce a first layer forming electrolyte composition.

<Second Layer Forming Electrolyte Composition>
6 g of the SPEEK solution obtained above and 0.7 g of ionic liquid (EMIm-HSO ₄ ⁻ ) were mixed and dispersed by a disperser to prepare a second layer forming electrolyte composition.

<Preparation of electrolyte membrane>
The first layer-forming electrolyte composition was coated on a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes to form a first layer having a thickness of 30 μm. Next, the second layer-forming electrolyte composition is applied onto the main surface of the first layer with a blade coater and dried at about 95 ° C. for about 60 minutes to form the second layer. A layer and a second layer were laminated. Thereafter, the PET film was peeled off from the first layer to obtain an ion conductive electrolyte membrane having a total thickness of 100 μm.

(Example 2)
<Solid acid>
As a solid acid, a composite of cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) prepared as follows (CsH ₂ PO ₄ / SiP ₂ O ₇ ) was used.

First, cesium dihydrogen phosphate (CsH ₂ PO ₄ ) was produced as follows. Liquid phosphoric acid is added dropwise to an aqueous solution of cesium carbonate (Cs ₂ CO ₃ ) with a stirrer using a stirrer or the like, and stirred at a temperature of about 100 to 150 ° C. for about 1 to 3 hours. The water was evaporated. In addition, cesium carbonate (Cs ₂ CO ₃ ) and liquid phosphoric acid were used in such an amount that 2 mol of liquid phosphoric acid was used per 1 mol of cesium carbonate. Then, it put into oven and dried for about 1 day at the temperature of about 100-150 degreeC. After drying, the obtained product was pulverized in an agate bowl to form a powder, and cesium dihydrogen phosphate (CsH ₂ PO ₄ ) was obtained.

Next, cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) obtained in the same manner as in Example 1 were blended in a molar number of 1: 2, and the resulting mixture was obtained. Was dispersed with a disperser to obtain a composite of cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ).

  As the liquid electrolyte, 1-ethyl-3-methylimidazolium triflate (manufactured by Merck Co., Ltd., hereinafter also referred to as EMIm-TfO), which is an ionic liquid, was used. As a binder, the SPEEK solution obtained in the same manner as in Example 1 was used.

<First Layer-Forming Electrolyte Composition>
20 g of the SPEEK solution obtained in the same manner as in Example 1 and 9 g of the composite of cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) obtained above were mixed with a disperser. -Disperse | distributed and produced the electrolyte composition for 1st layer formation.

<Second Layer Forming Electrolyte Composition>
Mix 0.1g of ionic liquid (EMIm-TfO) and 0.4g of cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) obtained above in a mortar. 2 layer forming electrolyte composition was produced.

<Preparation of electrolyte membrane>
The first layer-forming electrolyte composition was coated on a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes to form a first layer having a thickness of 10 μm. Next, the second layer-forming electrolyte composition was uniaxially pressed at a pressure of 3 MPa to produce pellets having a diameter of 1.2 cm and a thickness of 2 mm, thereby forming a second layer. Next, after laminating the first layer and the second layer so as to be in contact with the main surface of the first layer, the PET film was peeled off from the first layer to obtain an ion conductive electrolyte membrane.

(Example 3)
<First Layer-Forming Electrolyte Composition>
A first layer forming electrolyte composition was obtained in the same manner as Example 2.

<Second Layer Forming Electrolyte Composition>
20 g of SPEEK solution obtained in the same manner as in Example 1, 3 g of ionic liquid (EMIm-TfO), cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate (in the same manner as in Example 2) 6 g of a composite of SiP ₂ O ₇ ) was mixed and dispersed with a disperser to prepare a second layer forming electrolyte composition.

<Preparation of electrolyte membrane>
The first layer-forming electrolyte composition was coated on a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes to form a first layer having a thickness of 10 μm. Next, the second layer-forming electrolyte composition was coated on a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes to form a second layer having a thickness of 50 μm. Next, after peeling the PET film of the second layer, the first layer is laminated on both main surfaces of the second layer so that the second layer is sandwiched between the first layers. The PET film was peeled from this layer to obtain an ion conductive electrolyte membrane.

(Example 4)
<First Layer-Forming Electrolyte Composition>
A first layer forming electrolyte composition was obtained in the same manner as Example 2.

<Second Layer Forming Electrolyte Composition>
20 g of SPEEK solution obtained in the same manner as in Example 1, 7 g of ionic liquid (EMIm-TfO), cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate obtained in the same manner as in Example 2 ₂ g of the (SiP ₂ O ₇ ) composite was mixed and dispersed with a disperser to prepare a second layer-forming electrolyte composition.

<Preparation of electrolyte membrane>
An ion-conducting electrolyte membrane was obtained in the same manner as in Example 3 except that the first layer-forming electrolyte composition and the second layer-forming electrolyte composition obtained above were used.

(Example 5)
As the liquid electrolyte, EMIm-HSO ₄ ⁻ (manufactured by Merck Ltd.), which is an ionic liquid, was used. As a binder, the SPEEK solution obtained in the same manner as in Example 1 was used.

<Solid acid>
As a solid acid, a composite of potassium dihydrogen phosphate (KH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) prepared as follows was used (KH ₂ PO ₄ / SiP ₂ O ₇ ).

First, potassium dihydrogen phosphate (KH ₂ PO ₄ ) was produced as follows. While stirring with a stirrer using a stirrer or the like, liquid phosphoric acid is added dropwise to an aqueous solution of potassium carbonate (K ₂ CO ₃ ) and stirred at a temperature of about 100 to 150 ° C. for about 1 to 3 hours. The water was evaporated. In addition, potassium carbonate (K ₂ CO ₃ ) and liquid phosphoric acid were used in such an amount that the liquid phosphoric acid was 2 moles per mole of cesium carbonate. Then, it put into oven and dried for about 1 day at the temperature of about 100-150 degreeC. After drying, the obtained product was pulverized in an agate bowl to form a powder, and potassium dihydrogen phosphate (KH ₂ PO ₄ ) was obtained.

Next, potassium dihydrogen phosphate (KH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) obtained in the same manner as in Example 1 were blended in a molar ratio of 1: 2, and the resulting mixture was obtained. Was dispersed with a disperser to obtain a composite of potassium dihydrogen phosphate (KH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ).

<First Layer-Forming Electrolyte Composition>
20 g of the SPEEK solution obtained in the same manner as in Example 1 and 9 g of the complex of potassium dihydrogen phosphate (KH ₂ PO ₄ ) and silicon phosphate (SiP ₂ O ₇ ) obtained above were mixed using a disperser. -Disperse | distributed and produced the electrolyte composition for 1st layer formation.

<Second Layer Forming Electrolyte Composition>
Disperse 20 g of SPEEK solution obtained in the same manner as in Example 1, 6 g of ionic liquid (EMIm-HSO ₄ ⁻ ), and 3 g of silicon phosphate (SiP ₂ O ₇ ) produced in the same manner as in Example 1. A second layer forming electrolyte composition was prepared by mixing and dispersing.

<Preparation of electrolyte membrane>
An ion-conducting electrolyte membrane was obtained in the same manner as in Example 3 except that the first layer-forming electrolyte composition and the second layer-forming electrolyte composition obtained above were used.

(Example 6)
<Solid acid>
As a solid acid, a metal phosphate (tin phosphate) produced as follows was used. First, 13.56 g (0.09 mol) of tin oxide (SnO ₂ , manufactured by Nano Tec) and 1.40 g (0.0050 mol) of indium oxide (In ₂ O ₃ , manufactured by Nacalai Tesque) were added to dihydrogen phosphate. Ammonium (Nacalai Tesque) 27.99 g (0.212 mol) was added, and these were mixed with a spoon. Thereafter, the obtained mixture was put into a crucible and baked at about 650 ° C. for about 2 hours, and the obtained product was pulverized with an agate nail to obtain tin phosphate. The obtained tin phosphate is a pyrophosphate salt partially doped with indium (Sn _0.9 In _0.1 P ₂ O ₇ ).

  As the liquid electrolyte, EMIm-TfO (Merck Co., Ltd.), which is an ionic liquid, was used. As a binder, the SPEEK solution obtained in the same manner as in Example 1 was used.

<First Layer-Forming Electrolyte Composition>
A first layer-forming electrolyte composition was prepared by mixing and dispersing 20 g of the SPEEK solution obtained in the same manner as in Example 1 and 9 g of tin phosphate obtained above with a disperser.

<Second Layer Forming Electrolyte Composition>
20 g of the SPEEK solution obtained in the same manner as in Example 1, 2.5 g of ionic liquid (EMIm-TfO), and 6.5 g of tin phosphate obtained above were mixed and dispersed with a disperser to obtain a second solution. An electrolyte composition for layer formation was produced.

<Preparation of electrolyte membrane>
An ion-conducting electrolyte membrane was obtained in the same manner as in Example 3 except that the first layer-forming electrolyte composition and the second layer-forming electrolyte composition obtained above were used.

(Example 7)
<Solid acid>
As the solid acid contained in the first layer, cesium pentahydrogen diphosphate (CsH ₅ (PO ₄ ) ₂ ) prepared as follows was used. First, liquid phosphoric acid is dropped little by little into an aqueous solution of cesium carbonate (Cs ₂ CO ₃ ) while stirring with a stirrer using a stirrer or the like, and at a temperature of about 100 to 150 ° C. for about 1 to 3 hours. Stir to evaporate the water. In addition, cesium carbonate (Cs ₂ CO ₃ ) and liquid phosphoric acid were used in such an amount that 4 mol of liquid phosphoric acid was used per 1 mol of cesium carbonate. Thereafter, it was put in an oven and dried at a temperature of about 100 to 150 ° C. for about 1 day. After drying, the obtained product was pulverized in an agate bowl into a powder form to obtain cesium dihydrogen phosphate (CsH ₅ (PO ₄ ) ₂ ).

  As the liquid electrolyte, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (manufactured by Mitsubishi Materials Corporation, hereinafter also referred to as EMIm-SFI), which is an ionic liquid, was used.

<First Layer-Forming Electrolyte Composition>
The cesium pentahydrogen diphosphate (CsH ₅ (PO4) ₂ ) obtained above was used as the first layer forming electrolyte composition.

<Second Layer Forming Electrolyte Composition>
20 g of SPEEK solution obtained in the same manner as in Example 1, 2 g of ionic liquid (EMIm-SFI), cesium dihydrogen phosphate (CsH ₂ PO ₄ ) and silicon phosphate obtained in the same manner as in Example 2 7 g of the (SiP ₂ O ₇ ) composite was mixed and dispersed with a disperser to prepare a second layer forming electrolyte composition.

<Preparation of electrolyte membrane>
The second layer-forming electrolyte composition was applied onto a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes to form a second layer having a thickness of 50 μm. Next, the PET film is peeled off from the second layer, the first layer-forming electrolyte composition is disposed on both main surfaces of the second layer, heat-treated at 170 ° C. for 30 minutes, and then cooled at room temperature. By solidifying, the first layer was formed, and the first layer and the second layer were laminated to obtain an ion conductive electrolyte membrane having a thickness of 200 μm.

(Example 8)
<Liquid electrolyte>
In a glove box in an argon atmosphere, imidazole manufactured by Tokyo Chemical Industry Co., Ltd. (Imidazole, hereinafter referred to as Im) and HTFSI manufactured by Wako Pure Chemical Industries, Ltd. are slowly mixed at a molar ratio of 4: 1, and imidazolium bis (Trifluoromethanesulfonyl) amide (hereinafter referred to as Im4-HTFSI) was obtained.

<First Layer-Forming Electrolyte Composition>
A first layer forming electrolyte composition was obtained in the same manner as Example 2.

<Second Layer Forming Electrolyte Composition>
20 g of the SPEEK solution obtained in the same manner as in Example 1, 7 g of the ionic liquid (Im4-HTFSI) obtained above, and 2 g of silicon phosphate (SiP ₂ O ₇ ) obtained in the same manner as in Example 1. Were mixed and dispersed with a disperser to prepare a second layer forming electrolyte composition.

<Preparation of electrolyte membrane>
An ion-conducting electrolyte membrane was obtained in the same manner as in Example 3 except that the first layer-forming electrolyte composition and the second layer-forming electrolyte composition obtained above were used.

Example 9
<Liquid electrolyte>
In a glove box under an argon atmosphere, 2-ethylimidazole (2-ethylimidazole, hereinafter referred to as EtIm) manufactured by Tokyo Chemical Industry Co., Ltd. and HTFSI manufactured by Wako Pure Chemical Industries, Ltd. are slowly added at a molar ratio of 4: 1. By mixing, 2-ethylimidazolium bis (trifluoromethanesulfonyl) amide (hereinafter referred to as EtIm4-HTFSI) was obtained.

<First Layer-Forming Electrolyte Composition>
A first layer forming electrolyte composition was obtained in the same manner as Example 2.

<Second Layer Forming Electrolyte Composition>
20 g of the SPEEK solution obtained in the same manner as in Example 1, 7 g of the ionic liquid (EtIm4-HTFSI) obtained above, and cesium dihydrogen phosphate (CsH ₂ PO ₄ ) obtained in the same manner as in Example 2. ) And 2 g of a composite of silicon phosphate (SiP ₂ O ₇ ) were mixed and dispersed with a disperser to produce a second layer forming electrolyte composition.

<Preparation of electrolyte membrane>
An ion-conducting electrolyte membrane was obtained in the same manner as in Example 3 except that the first layer-forming electrolyte composition and the second layer-forming electrolyte composition obtained above were used.

(Comparative Example 1)
An electrolyte composition prepared by mixing and dispersing 18 g of the SPEEK solution obtained in the same manner as in Example 1 and 0.1 g of ionic liquid (EMIm-SFI) with a disperser on a PET film (thickness: 25 μm) with a blade coater. And dried at about 95 ° C. for about 60 minutes, and then the PET film was peeled off to obtain an ion conductive electrolyte membrane having a thickness of 60 μm.

(Comparative Example 2)
An electrolyte composition prepared by mixing and dispersing 16 g of the SPEEK solution obtained in the same manner as in Example 1 and 0.2 g of ionic liquid (EMIm-SFI) with a disperser on a PET film (thickness: 25 μm) with a blade coater. Then, after drying at about 95 ° C. for about 60 minutes, the PET film was peeled off to obtain an ion conductive electrolyte membrane having a thickness of 70 μm.

(Comparative Example 3)
The electrolyte composition used as the first layer-forming electrolyte composition in Example 1 was coated on a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes, and then the PET film was The film was peeled off to obtain an ion conductive electrolyte membrane having a thickness of 60 μm.

(Comparative Example 4)
The electrolyte composition used as the second layer-forming electrolyte composition in Example 4 was coated on a PET film (thickness: 25 μm) with a blade coater and dried at about 95 ° C. for about 60 minutes, and then the PET film was Peeling was performed to obtain an ion conductive electrolyte membrane having a thickness of 60 μm. However, handling was difficult due to lack of independence. Moreover, it was confirmed visually that the ionic liquid oozes out on the surface of the ion conductive electrolyte membrane.

  The ionic conductivity of the electrolyte membrane obtained in Examples and Comparative Examples was measured by the following method, and the results are shown in Tables 1 to 3 below. Tables 1 to 3 also show each composition of the electrolyte composition and its content.

(Ion conductivity measurement)
The electrolyte membrane was subjected to AC impedance load with an electrochemical measurement device (1255WB type, manufactured by Solartron), and proton conductivity was measured at a temperature of 160 ° C. and in a non-humidified environment.

  The electrolyte membranes obtained in Examples 1 to 9 all have a proton conductivity higher than that of Comparative Examples 1 to 3 at a temperature of 160 ° C. and in a non-humidified environment. Moreover, in the electrolyte membrane obtained in Examples 1-9, the ionic liquid oozing out from the electrolyte membrane as observed in Comparative Example 4 was not visually confirmed. In addition, the electrolyte membranes obtained in Examples 1 to 9 were superior in mechanical strength to the electrolyte membrane of Comparative Example 4 and were self-supporting.

  From the above, it was found that the electrolyte membrane of the present invention has excellent mechanical strength and is self-supporting, and does not exude liquid electrolyte from the electrolyte membrane and has high ionic conductivity in a non-humidified state.

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

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c 1st layer 2, 2a, 2b 2nd layer 6, 7 Catalyst layer 10 Electrolyte membrane 16 Cathode side catalyst electrode 17 Anode side catalyst electrode 20 Catalyst layer-electrolyte membrane laminated body 21 Fuel flow path 22 Oxidant gas flow path 23 External circuit 28, 29 Separator 30 Membrane electrode assembly 40 Fuel cell

Claims (9)

An electrolyte membrane containing a liquid electrolyte and a solid acid,
Including at least a first layer and a second layer;
The first layer comprises a solid acid;
The second layer includes a liquid electrolyte;
An electrolyte membrane, wherein a first layer is disposed on an outermost layer on one or both sides of the electrolyte membrane.   The electrolyte membrane according to claim 1, wherein the first layer is disposed on an outermost layer on both sides of the electrolyte membrane.   The electrolyte membrane according to claim 1, wherein the second layer further contains a solid acid.   The electrolyte membrane according to claim 1, wherein at least one of the first layer and the second layer contains a binder.   The electrolyte membrane according to claim 1, wherein the liquid electrolyte is an ionic liquid.   The electrolyte membrane according to any one of claims 1 to 5, wherein the liquid electrolyte is an ionic liquid containing ions having proton donating properties and / or proton accepting properties. The electrolyte membrane according to any one of claims 1 to 6 and a pair of catalyst layers,
The catalyst layer-electrolyte membrane laminate, wherein the catalyst layers are respectively disposed on both main surfaces of the electrolyte membrane. The electrolyte membrane according to any one of claims 1 to 6 and a pair of catalyst electrodes,
The membrane electrode assembly, wherein the catalyst electrodes are respectively disposed on both main surfaces of the electrolyte membrane.   The electrolyte membrane according to any one of claims 1 to 6, a pair of catalyst electrodes, and a pair of separators, wherein the catalyst electrodes and the separators are arranged in this order on both main surfaces of the electrolyte membrane. A fuel cell, wherein each of the fuel cells is laminated.

Images