WO2008004567A1

WO2008004567A1 - Solid polymer electrolyte membrane and fuel cell

Info

Publication number: WO2008004567A1
Application number: PCT/JP2007/063343
Authority: WO
Inventors: Masahiro Kurokawa; Yoshihiro Gocho
Original assignee: Mitsubishi Gas Chemical Company, Inc.
Priority date: 2006-07-06
Filing date: 2007-07-04
Publication date: 2008-01-10
Also published as: JPWO2008004567A1

Abstract

Disclosed is a solid polymer electrolyte membrane which is excellent in methanol impermeability, while maintaining high proton conductivity. Also disclosed is a fuel cell comprising such a solid polymer electrolyte membrane. Specifically disclosed is a solid polymer electrolyte membrane which is obtained by impregnating a polyolefin porous membrane with a vinyl monomer having a basic group and a crosslinkable vinyl monomer, at least one of which monomers has an aromatic ring or a heterocyclic ring, then polymerizing the monomers, and then subjecting the resulting membrane to a sulfonation treatment. Also specifically disclosed is a fuel cell comprising the solid polymer electrolyte membrane, and a positive electrode and a negative electrode sandwiching the solid polymer electrolyte membrane.

Description

Specification

Solid polymer electrolyte membrane and fuel cell

Technical field

TECHNICAL FIELD [0001] The present invention relates to a solid polymer electrolyte membrane and a fuel cell excellent in proton conductivity and methanol permeation blocking properties.

Background art

In recent years, fuel cells are occupying an important position as next-generation clean energy sources. Among the fuel cells, a polymer electrolyte fuel cell (hereinafter referred to as PEFC) has both an anode and a force sword arranged with a solid polymer electrolyte membrane in between. For example, in the case of a direct methanol fuel cell (hereinafter referred to as DMFC) that uses methanol as the fuel, an electrochemical reaction occurs by supplying methanol to the negative electrode side and oxygen or air to the positive electrode side. Is generated.

[0003] In order to realize a small and lightweight fuel cell that maintains the characteristics of high output and high energy density, it is high!ヽ Development of solid polymer electrolyte membranes with proton conductivity. The solid polymer electrolyte membrane used in the DMFC has high ionic conductivity while preventing permeation of methanol for fuel, that is, the anode side force of the solid polymer electrolyte membrane is also permeated to the sword side. Reduction of (crossover) is required.

[0004] Conventionally, a hydrated perfluorocarbon sulfonic acid (hereinafter referred to as PFS) polymer (for example, Nafion [registered trademark]) has high ionic conductivity, so that a solid polymer electrolyte is used. Widely used as a membrane. However, a hydrated PFS polymer membrane has a high affinity with water, and has a theoretical limit to methanol permeation prevention properties as soon as it permeates methanol. As a means of reducing the methanol crossover of PFS polymer hydrated membranes, it is conceivable to combine different materials based on PFS polymer hydrated membranes. However, such a composite significantly reduced the high ionic conductivity of the original PFS polymer hydrated membrane.

[0005] As a method for solving these problems, a naphthyl (registered trademark) membrane is impregnated with arlin to form polyaline, thereby exhibiting the same ionic conductivity as the naphth ion (registered trademark) membrane. However, it is disclosed that the permeation amount of methanol per unit time can be suppressed to about 1 Z3 as compared with a naphthion (registered trademark) membrane (for example, see Patent Document 1). However, the use of the above membrane as an electrolyte membrane for DMFC is still inadequate in terms of methanol permeation blocking properties. Further, since the expensive naphthion (registered trademark) film is further processed, the number of steps becomes complicated and the film becomes more expensive.

[0006] In addition, an acidic monomer is graft-polymerized on a porous membrane (for example, see Patent Document 2), and a matrix monomer, an ion exchange monomer and an alignment monomer are copolymerized (for example, a patent). Reference 3), those in which an acidic or basic monomer is graft-polymerized on a porous membrane and an inorganic filler is further added (for example, see Patent Document 4), those in which a porous membrane is filled with a cation exchange resin (for example, Patent Document 5), and polymers obtained by doping acid with a polymer of acroaminotetrazole or butyrazole (for example, see Patent Document 6) are also disclosed.

[0007] Prior to this, polyethyleneimine was doped with sulfuric acid or phosphoric acid (see Non-Patent Document 1), polysilamine was doped with phosphoric acid (see Non-Patent Document 2), polyacrylamide was sulfuric acid, Or phosphoric acid doped (see Non-patent Document 3), Polybenzimidazole doped with phosphoric acid (see Patent Document 7), Sulfony-polyether sulfone with polybenzimidazole added (Non-patent) (Refer to Reference 4.) However, there are many problems such as the dopant flowing down and not showing sufficient ionic conductivity.

Patent Document 1: Japanese Patent Laid-Open No. 2001-81220

Patent Document 2: Patent WO00,54351

Patent Document 3: Japanese Patent Laid-Open No. 11-302410

Patent Document 4: Japanese Patent Laid-Open No. 2003-157862

Patent Document 5: Japanese Unexamined Patent Publication No. 2001-135328

Patent Document 6: JP-A-2005-71961

Patent Document 7: Japanese Patent Publication No. 11-503262

Special Reference 1: D. Schoolmann, O. Trinquent, ana J.-C. Lassegues, Electrochim Acta, j7, 1619 (1992)

Non-Patent Document 2: K. Tsuruhara, M. Rikukawa, K. Sunui, N. Ogata, Y. Nagasaki, and M. Kato, E lectrochim Acta, 45, 1391 (2000)

Non-Patent Document 3: W. Wieczorek and J.R. Stevens, Polymer, 38, 2057 (1997)

Non-Patent Document 4: J. Kerrer, A. Ullrich, F. Meier and T. Harig, Solid State Ionics, 125, 243 (19

99)

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention was made in order to solve the current problems of the PFS polymer hydration film, the PFS modified film, and various electrolyte films as the solid polymer electrolyte film for DMFC as described above. Another object of the present invention is to provide a solid polymer electrolyte membrane excellent in methanol permeation-preventing property while maintaining high proton conductivity, and a fuel cell including the solid polymer electrolyte membrane.

Means for solving the problem

[0009] As a result of intensive studies on the above problems, the present inventors have impregnated a porous monomer made of polyolefin with a vinyl monomer having a basic group and a crosslinkable vinyl monomer, followed by polymerization. (1) SO H) to obtain a solid polymer electrolyte membrane,

Three

The inventors have found that the methanol permeation-preventing property can be improved while maintaining high ionic conductivity, leading to the present invention. That is, the present invention is as follows.

[0010] 1. At least one of a vinyl monomer having a basic group and a crosslinkable vinyl monomer has an aromatic ring or a heterocyclic ring, and these monomers are impregnated into a polyolefin porous membrane and polymerized, followed by sulfonation. A solid polymer electrolyte membrane obtained by treatment.

2. The solid polymer electrolyte membrane according to the above item 1, which is a vinyl monomer having 2 basic groups and having 2 bullypyridine or 4 vinyl pyridine.

3. The solid polymer electrolyte membrane according to 1 above, wherein the crosslinkable bull monomer is a divinyl compound.

4. The solid polymer electrolyte membrane as described in 3 above, wherein the divinyl compound is dibutenebenzene.

5. The molar ratio of the charge when impregnating the vinyl monomer having a basic group and the crosslinkable vinyl monomer (the number of moles of a bull monomer having a basic group) 2. The polymer electrolyte membrane according to 1 above, wherein the number of moles of monomer) force ranges from 20Z80 to 90Z10.

6. The solid polymer electrolyte membrane according to 1 above, wherein the weight increase rate due to the sulfonating treatment is in the range of 10 to 80%.

7. The solid polymer according to 1 above, wherein, when impregnating the vinyl monomer having a basic group and the crosslinkable vinyl monomer, a third monomer copolymerizable with these monomers is further included. Electrolyte membrane.

8. The solid polymer electrolyte membrane according to 7 above, wherein the third monomer is composed of at least any one of styrene, bullnaphthalene, acrylamide-sodium t-butylsulfonate, and sodium bulesulfonate.

9. The solid polymer electrolyte membrane according to 1 above, wherein the polyolefin porous membrane is a polyethylene porous membrane.

10. The solid polymer electrolyte membrane according to 1 or 9 above, wherein the polyolefin porous membrane is hydrophilized.

11. The solid according to 1 above, wherein the polymer component comprising the beryl monomer having a basic group and the crosslinkable butyl monomer is contained in an amount of 30 to 100 parts by mass with respect to 100 parts by mass of the polyolefin porous membrane. Polymer electrolyte membrane.

12. 100 parts by mass of the polyolefin porous membrane contains 30 to L00 parts by mass of a polymer component composed of the basic monomer-containing monomer, the cross-linkable butyl monomer, and the third monomer. 8. The solid polymer electrolyte membrane according to 7 above.

13. A fuel cell comprising the solid polymer electrolyte membrane according to 1 above, and a positive electrode and a negative electrode sandwiching the solid polymer electrolyte membrane.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram showing an example of a fuel cell using a solid polymer electrolyte membrane.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] (Polymer electrolyte membrane)

The solid polymer electrolyte membrane of the present invention is obtained by impregnating a polyolefin porous membrane with a vinyl monomer having a basic group and a crosslinkable butyl monomer, followed by polymerization and then sulfonation treatment. Obtained. At least one of the vinyl monomer having a basic group and the crosslinkable vinyl monomer has an aromatic ring or a heterocyclic ring.

[0013] Examples of the vinyl monomer having a basic group include acrylamide, arylamine, berylpyrrolidone, belimidazole, aminoacrylamide, belaminosulfone, bilyridine, dimethylaminoethyl (meth) acrylate and beercaprolatatam. , Berylcarbazole, vinyldiaminotriazine, ethyleneimine, and the like that contain a nitrogen atom in the molecule. In particular, 2-bulupyridine, 4-bulupyridine or a mixture thereof is preferable.

[0014] Examples of the crosslinkable butyl monomer include dibutyl benzene, tetraethylene glycol dimetatalylate, methylene bisacrylamide, ethylene glycol dimetatalylate, diethylene glycol dimetatalylate, triethylene glycol dimetatalylate, and nonaethylene. Examples include dibule compounds such as glycol dimetatalylate. In particular, dibulene benzene is preferred.

Note that at least one of the vinyl monomer having a basic group and the cross-linkable vinyl monomer has an aromatic ring or a heterocyclic ring.

In addition to the vinyl monomer having a basic group and the crosslinkable vinyl monomer, a third monomer copolymerizable with these monomers and a solvent (including a plasticizer) may be added as necessary.

[0016] Examples of the third monomer include styrene, urnaphthalene, sodium acrylamide-butyrylsulfonate, sodium vinylsulfonate, and the like.

[0017] Examples of the solvent include toluene, xylene, dimethyl sulfoxide, dimethylformamide, alcohols, and the like.

In the present invention, a so-called plasticizer can also be used as a solvent. For example, powers such as tributyl acetyl citrate, dibutyl phthalate, dioctyl phthalate, dibutyl adipate, and tributyl daricerol are not limited to these. What is necessary is just to select suitably considering a boiling point, a viscosity, the impregnation property to a polyolefin membrane, etc.

[0019] The molar ratio of the charge when impregnating the vinyl monomer having a basic group and the crosslinkable vinyl monomer (the number of moles of the bull monomer having a basic group) The number of moles) is preferably in the range of 20/80 to 90/10. By being in the strong range, good film-forming property is shown, and good proton conductivity and excellent methanol permeation-preventing property can be expressed through a sulfone cocoon process described later. The molar ratio is more preferably in the range of 70/30 to 40/60, more preferably in the range of 60Z40 to 50Z50.

[0020] When the third monomer is added, the number of moles of butyl monomer having a basic group

The ratio of the total number of moles (Q) and the third monomer (Q) to the number of moles (R) of the crosslinkable butyl monomer, that is, (P + Q) ZR is in the range of 20Ζ80 to 90Ζ10, and the base It is preferable that the molar ratio (PZQ) of the butyl monomer having a functional group and the third monomer is in the range of 10Z90 to 99Zl.

[0021] Copolymerization of a vinyl monomer having a basic group and a crosslinkable butyl monomer can be initiated by heat, light, electron beam, or the like. In the case of polymerization by heat, a radical polymerization initiator, a cationic polymerization initiator or a cation polymerization initiator can be used. A radical polymerization initiator is preferred. In particular, when peroxide compounds with high hydrogen abstraction ability are used, in addition to the polymerization reaction between the butyl monomer having a basic group and the crosslinkable butyl monomer, a crosslinked structure is also formed with the porous membrane made of polyolefin. Therefore, the strength and durability of the obtained solid polymer electrolyte membrane are improved, which is preferable. As such a radical initiator, for example, an organic peracid salt described in a catalog of Nippon Oil & Fats Co., Ltd. can be used. In particular, t-butyl peroxide 2-ethylhexyl carbonate and benzoyl peroxide are preferable.

[0022] The addition amount of the polymerization initiator depends on the polymerization conditions, but is 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, more preferably 100 parts by weight of the total amount of raw material monomers used. Is 0.05 to 2 parts by weight. The polymerization temperature is 0 ° C to 120 ° C, preferably 20 ° C to 100 ° C, more preferably 30 ° C to 80 ° C. Consider the monomer composition, physical properties of the resulting polymer, process time, etc. And choose as appropriate.

In the present invention, polyolefin is used as a raw material for the porous membrane used in the present invention.

Specifically, forces including polyethylene, polypropylene, polystyrene and the like are not limited to these. Preferably polyethylene, particularly preferably ultrahigh molecular weight polyethylene is used. I can.

[0024] The weight average molecular weight of the polyolefin is 50,000 or more, preferably 1 million or more, more preferably 5 million or more.

[0025] The average pore diameter of the porous porous polyolefin membrane used in the present invention is 0.001 to 5 μm, preferably 0.001 to 1 / ζ πι, and more preferably 0.00 to 0.05. It is.

[0026] The porosity of the polyolefin porous membrane used in the present invention is 20 to 60%, preferably 30 to 50%, more preferably 35 to 45%.

[0027] The thickness of the porous polyolefin membrane used in the present invention is usually 1 to 300 m, preferably 5 to: LOO μm, more preferably 10 to 50 μm.

[0028] The air permeability of the polyolefin porous membrane used in the present invention is 100 to 900 seconds ZlOOml, preferably 150 to 750 seconds ZlOOml, more preferably 200 to 650 seconds ZlOOml.

[0029] Examples of the porous membrane made of polyolefin used in the present invention include Hypore (registered trademark) manufactured by Asahi Kasei Chemicals Co., Ltd., Solpore (registered trademark), Solfil (registered trademark), Mitsui Examples include ESPOAR (registered trademark) manufactured by Gaku Co., Ltd., SETILA (registered trademark) manufactured by TonenGeneral Sekiyu KK, and YUPO (registered trademark) manufactured by YUPO Corporation.

[0030] In addition, the polyolefin porous membrane used in the present invention is preferably hydrophilized prior to impregnation described later! A known method can be applied to the hydrophilization treatment, and the hydrophilization treatment is not limited. By such a hydrophilization treatment, the permeability of the raw material monomer to the porous membrane can be further enhanced in the impregnation described later.

[0031] The polyolefin porous membrane is impregnated with a raw material composition containing a butyl monomer having a basic group, a cross-linkable vinyl monomer, and a polymerization initiator. The impregnation treatment is performed by a known method and is not limited. For example, a porous membrane made of polyolefin is immersed in the raw material composition, and is sandwiched between release films such as PET to remove excess raw material composition. For example, by applying a roller or the like, it is possible to fill the details of the porous membrane with a necessary and sufficient amount of the raw material composition liquid at the same time as the removal of excess raw material yarns and components. The impregnation treatment is usually performed under normal temperature and normal pressure, but may be performed under pressure or under reduced pressure as necessary. [0032] After the impregnation treatment, polymerization is performed. The impregnated porous membrane is sandwiched between glass plates through the above release film and polymerized by heating in a nitrogen atmosphere. The polymerization conditions may be appropriately selected in consideration of the type of polymerization initiator and the composition of the raw material composition.

[0033] The film obtained by polymerization is immersed in a commonly used solvent such as acetone and methanol to remove the solvent and unreacted substances, and then dried.

[0034] After drying, sulfonation treatment is performed. A general method using fuming sulfuric acid or black sulfuric acid can be applied to the sulfonation treatment. The rate of weight increase due to sulfonation treatment ((weight of polymer after sulfonation treatment-weight of polymer before sulfonation treatment) Z weight of polymer before sulfonation treatment X 100) is in the range of 10-80% preferable. Within this range, the balance of proton conductivity, methanol permeation blocking property and mechanical strength of the solid polymer electrolyte membrane can be maintained. The weight increase rate due to the sulfonation treatment is more preferably 20 to 70%, particularly preferably 30 to 60%.

[0035] Since a sulfonic acid group is introduced into the polymer having a basic group by the sulfonation treatment, a solid polymer electrolyte membrane in which an acidic group and a basic group coexist, more specifically, an acidic group and a basic group. As a result, a solid polymer membrane can be obtained in which salts are formed within and between molecules of acidic and basic groups. The PFS polymer membrane is a force that requires water to intervene because protons are transferred in the form of hydrogen ions. The Grotthuss Mechanism does not require water between the salts in the electrolyte membrane of the present invention. Protons are thought to be transmitted. Therefore, protons are transferred smoothly between adjacent salts toward the negative electrode and the positive electrode. Further, since the salt has higher affinity with water than methanol, it exhibits excellent methanol permeation-preventing properties. By this action, water generated on the positive electrode side by power generation can be guided to the negative electrode side, and power generation can be continued by supplementing water necessary for the reaction on the negative electrode side. As a result, it is possible to use high-concentration methanol as fuel, which is extremely difficult with conventional PFS polymer membranes.

[0036] As described above, a solid polymer electrolyte membrane having proton conductivity (25 ° C) similar to that of naphthion (registered trademark) can be obtained.

[0037] In addition, a solid polymer electrolyte membrane having a methanol permeation rate (40 ° C, 30% aqueous methanol solution) power of ¾ mgZcm ² Zmin or less can be obtained. [0038] (Fuel cell)

As shown in FIG. 1, by sandwiching the solid polymer electrolyte membrane 1 of the present invention between the positive electrode 2a and the negative electrode 2b, a fuel cell excellent in methanol permeation-preventing property while maintaining high ionic conductivity is obtained. It is done. Further, the gas diffusion layer 3 may be provided on the surfaces of the positive electrode 2a and the negative electrode 2b. By this gas diffusion layer 3, gases such as methanol and oxygen used for power generation are diffused and uniformly distributed on the surfaces of the positive electrode 2a and the negative electrode 2b.

[0039] The ability to describe the present invention more specifically with reference to the following examples The present invention is not limited to these examples. Measurement of proton conductivity and methanol permeation rate was performed as follows.

[0040] (Proton conductivity measurement)

The proton conductivity of the solid polymer electrolyte membrane of the present invention was measured using an impedance analyzer SI1260 manufactured by Solartron, UK, at 25 ° C and 100% humidity, 3 hours after the sample was mounted in the measurement cell. High frequency impedance measurements were made. Next, the direct current component R was read from the Col Col plot, and the proton conductivity (Ωcm ² ) was calculated.

[0041] (Measurement of methanol permeation rate)

The methanol permeation rate of the solid polymer electrolyte membrane of the present invention was measured according to the following method. The obtained solid polymer electrolyte membrane was sandwiched in the center of the communication tube, 100 ml of 30% methanol aqueous solution was charged on one side, and 100 ml of ion exchange water on the other side, and immersed in a constant temperature water bath at 40 ° C. After 3 hours, methanol permeating into the water side was quantified by gas chromatography and the methanol permeation rate (mg / cm ² / min) was calculated.

[Example 1]

2 Butylpyridine 31. 53 g (0.3 mol), 55% -dibutenebenzene (solvent: mixed xylene) 47. 35 g (0.2 mol) and t-butylperoxy-2-ethylhexyl carbonate 2.87 g (0.012 mol) ) 【This cetinolequenate tribubutinole 11. 83g was uniformly removed. This is called monomer solution A.

Polyethylene porous membrane (Asahi Kasei Chemicals Co., Ltd. “Hypore N9420G” (registered trademark)) impregnated with monomer solution A, hydrophilicized beforehand by corona discharge treatment, sandwiched between PET films, and further sandwiched between glass plates, Reacted at 80 ° C for 20 hours under nitrogen atmosphere Let

The obtained film was immersed in acetone to remove unreacted materials, tributyl acetyl citrate, xylene and the like, and then sufficiently dried. The obtained film was a uniform translucent film with no repellent spots.

The membrane is then immersed in fuming sulfuric acid (SO concentration: 2 to 3 wt%) and reacted at 60 ° C for 90 minutes.

Three

Let Sulfuric acid adhering to the obtained membrane was thoroughly washed with water. A glossy black-brown film was obtained. The weight increase rate due to the sulfonating treatment was 38%.

When the proton conductivity and methanol permeation rate of the solid polymer electrolyte membrane thus obtained were measured, 0.2 Q

1. was 2mgZcm ² Zmin.

[0043] (Example 2)

2-Burpyridine 15.77g (0.15mol), 55% -Dibutenebenzene (solvent: mixed xylene) 47.35g (0.2mol), styrene monomer 20.84g (0.2mol) and t-butyl butadiene 1.13 g (0.013 mol) of 2-ethylhexyl carbonate was dissolved in 12.59 g of tributyl acetyl citrate. This is called monomer solution B.

A polyethylene porous membrane that has been hydrophilized by corona discharge treatment ("Hypore N9420G" (registered trademark) manufactured by Asahi Kasei Chemicals Co., Ltd.) is impregnated with the monomer solution B, sandwiched between PET films, and further sandwiched between glass plates. The reaction was carried out at 80 ° C for 20 hours in a nitrogen atmosphere.

Three

Let Sulfuric acid adhering to the obtained membrane was thoroughly washed with water. A glossy black-brown film was obtained. The rate of weight increase due to this sulfone treatment was 40%.

The proton conductivity and methanol permeation rate of the solid polymer electrolyte membrane thus obtained were measured.

0.8 mgZcm ² Zmin.

[0044] (Example 3)

4-Bulupyridine 32.90g (0.3 mol), 55% -dibutenebenzene (solvent: mixed xyle 49.30 g (0.2 mol) and t-butylperoxy-2-ethylhexyl carbonate 3.00 g (0.012 mol) [Tributinole cetinolecate] 17.80 g was uniformly distributed. This is called monomer solution C.

Polyethylene porous film (Asahi Kasei Chemicals Co., Ltd. "Hypore N9420G" (registered trademark) impregnated with monomer solution A, hydrophilicized beforehand by corona discharge treatment, sandwiched between PET films, and further sandwiched between glass plates, The reaction was carried out at 80 ° C for 20 hours in a nitrogen atmosphere.

The membrane is then immersed in fuming sulfuric acid (SO concentration: 3-4 wt%) and reacted at 70 ° C for 85 minutes.

Three

Let Sulfuric acid adhering to the obtained membrane was thoroughly washed with water. A glossy black-brown film was obtained. The weight increase rate by this sulfone treatment was 48%.

2. OmgZcm ² Zmin.

(Example 4)

4 Butylpyridine 20.4g (0.19mol), 55% -Dibutylbenzene (solvent, mixed xylene) 70.9g (0.3mol), Styrene monomer 40.4g (0.39mol) and t-butyl peroxide 2 Ethylhexyl carbonate 5.0 g (0.02 mol) was dissolved in acetyl acetyl citrate 15. Og. This is called monomer solution D.

A polyethylene porous membrane that has been hydrophilized by corona discharge treatment ("Hypore NA635" (registered trademark) manufactured by Asahi Kasei Chemicals Co., Ltd.) is impregnated with the monomer solution C, sandwiched between PET films, and further sandwiched between glass plates. The reaction was carried out in a nitrogen atmosphere for 20 hours at 80 ° C. The obtained film was a uniform translucent film with no repellency spots.

The obtained film was immersed in acetone to remove unreacted materials, tributyl acetyl citrate, xylene and the like, and then sufficiently dried.

The membrane is then immersed in fuming sulfuric acid (SO concentration: 2 to 3 wt%) and reacted at 70 ° C for 30 minutes.

Three

Let Sulfuric acid adhering to the obtained membrane was thoroughly washed with water. A glossy black-brown film is obtained It was. The weight increase rate by this sulfone treatment was 34%.

0.6 mgZcm ² Zmin.

[Example 5]

The fuel cell assembly kit manufactured by Chemix Co., Ltd. Pem Master PEM— 004DM incorporates the solid polymer electrolyte membrane obtained in Example 1 instead of the naphthion (registered trademark) membrane, and 30% methanol is used as the fuel tank. (Volume: 4 ml). As a result, power was generated until the fuel was exhausted, and the motor was rotated.

[Example 6]

A negative electrode catalyst prepared by mixing a carbon material carrying a ruthenium monoplatinum catalyst and a perfluorosulfonic acid ion-exchanged resin (manufactured by DuPont, Nafion (registered trademark)) and applying it to a carbon paper. A positive electrode side catalyst layer prepared by mixing a layer, and a carbon material carrying a platinum catalyst and a perfluorosulfonic acid ion exchange resin (manufactured by DuPont, Naphion (registered trademark)) and applying it to carbon paper, A fuel cell was fabricated by sandwiching the solid polymer electrolyte membrane obtained in Example 1 with these two catalyst layers. When the temperature of the fuel cell was kept at 40 ° C., 10% methanol was supplied to the negative electrode side and air was supplied to the positive electrode side, a maximum output of 34 mWZcm ² was obtained.

[0048] (Comparative Example 1)

Measurement of proton conductivity and methanol permeation rate of perfluorosulfonic acid ion exchange membrane (DuPont, Nafion 117 (registered trademark)) was 0.4 Q cm ² and 4.8 mgZ cm / min, respectively. At once.

[0049] (Comparative Example 2)

The proton conductivity and methanol permeation rate of perfluorosulfonic acid ion exchange membrane (DuPont, Nafion 112 (registered trademark)) were measured, and 0.1 Ωcm ² and 6.8 mgZ cm / min, respectively. At once.

[0050] (Comparative Example 3)

A carbon paper carrying a ruthenium monoplatinum catalyst and a perfluorosulfonic acid ion-exchanged resin (manufactured by DuPont, Nafion (registered trademark)) solution are mixed to obtain a carbon paper. A negative electrode side catalyst layer prepared by coating the same, a carbon material carrying a platinum catalyst and a perfluorosulfonic acid ion exchange resin (manufactured by DuPont, Nafion (registered trademark)) solution were mixed and applied to carbon paper. The produced positive electrode side catalyst layer was produced, and a fuel cell was produced by sandwiching a naphthion 117 (registered trademark) membrane between these two catalyst layers. When the temperature of this fuel cell was kept at 40 ° C., 10% methanol was supplied to the negative electrode side and air was supplied to the positive electrode side, the maximum output llmWZcm ² was obtained.

Industrial applicability

The solid polymer electrolyte membrane of the present invention has both high proton conductivity and excellent methanol permeation inhibiting properties. The electrolyte membrane is useful for fuel cells such as DMFC and PEFC. Moreover, the production of the solid polymer electrolyte membrane of the present invention is simple and can be produced at low cost.

Claims

The scope of the claims

[I] At least one of a vinyl monomer having a basic group and a crosslinkable vinyl monomer has an aromatic ring or a heterocyclic ring, and these monomers are impregnated in a porous polyolefin membrane and polymerized, followed by sulfonation treatment. A solid polymer electrolyte membrane obtained.

[2] The solid polymer electrolyte membrane according to [1], wherein the basic monomer-containing vinyl monomer is 2-vinylpyridine or 4-vinylpyridine.

[3] The solid polymer electrolyte membrane according to [1], which is a crosslinkable vinyl monomer strength divinyl compound.

[4] The solid polymer electrolyte membrane according to [3], wherein the Jibi-Louis compound is dibulebenzene.

[5] The molar ratio of the charge when impregnating the vinyl monomer having the basic group and the crosslinkable bull monomer (number of moles of the bull monomer having basic group Z number of moles of the crosslinkable vinyl monomer) force 20Z80 to The solid polymer electrolyte membrane according to claim 1, which is in the range of 90Z10.

6. The solid polymer electrolyte membrane according to claim 1, wherein the rate of weight increase due to the sulfonating treatment is in the range of 10 to 80%.

[7] When impregnating the vinyl monomer having a basic group and the crosslinkable butyl monomer, a solid monomer according to claim 1, further comprising a third monomer copolymerizable with these monomers. Molecular electrolyte membrane.

8. The solid polymer electrolyte membrane according to claim 7, wherein the third monomer is composed of at least one of styrene, bullnaphthalene, acrylamide-sodium butyl sulfonate, and sodium bule sulfonate.

9. The solid polymer electrolyte membrane according to claim 1, wherein the polyolefin porous membrane is a polyethylene porous membrane.

[10] The solid polymer electrolyte membrane according to [1] or [9], wherein the polyolefin porous membrane is hydrophilized.

[II] 100 parts by mass of the polyolefin porous membrane contains 30 to: LOO parts by mass of a polymer component composed of the butyl monomer having the basic group and the crosslinkable vinyl monomer. 2. The solid polymer electrolyte membrane according to claim 1, wherein

[12] For 100 parts by mass of the polyolefin porous membrane, 3 polymer components composed of the butyl monomer having the basic group, the crosslinkable vinyl monomer, and the third monomer are included.

The solid polymer electrolyte membrane according to claim 7, which is contained in an amount of 0 to 100 parts by mass.

13. A fuel cell comprising the solid polymer electrolyte membrane according to claim 1, and a positive electrode and a negative electrode sandwiching the solid polymer electrolyte membrane.