JP2005339991A - Polyelectrolyte film, and solid polymer fuel cell and direct methanol type fuel cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polyelectrolyte film with superior proton conductivity and gas breaking property, and to provide a solid polymer fuel cell and a direct methanol type fuel cell that develop superior generation characteristics. <P>SOLUTION: The polyelectrolyte film comprises a sulfonic acid group and a hydrocarbon system high molecular compound, wherein a hydrogen permeation factor and/or an oxygen permeation factor at 23°C are 5.0×10<SP>-10</SP>(cm<SP>3</SP>cm)/(cm<SP>2</SP>s cmHg) or less and 5.0×10<SP>-11</SP>(cm<SP>3</SP>cm)/(cm<SP>2</SP>s cmHg) or less, respectively. In the polyelectrolyte film, a hydrogen permeation factor and/or an oxygen permeation factor at 80°C are 7 times the hydrogen permeation factor or less and 10 times the oxygen permeation factor at 23°C or less, respectively. The solid polymer fuel cell and the direct methanol type fuel cell employ the polyelectrolyte film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polymer electrolyte membrane, and a solid polymer fuel cell and a direct methanol fuel cell using the same.

  Polymer electrolyte membranes made of polymer compounds having proton-conductive substituents such as sulfonic acid groups are used as materials for electrochemical devices such as solid polymer fuel cells, humidity sensors, gas sensors, and electrochromic display devices. The Among these electrochemical devices, solid polymer fuel cells are expected as one of the pillars of new energy technology. Solid polymer fuel cells that use proton-conducting polymer electrolyte membranes can be operated at low temperatures and can be reduced in size and weight, so they can be used in mobiles such as automobiles, household cogeneration systems, and consumer-use compacts. Application to portable devices is under consideration. Among them, direct methanol fuel cells that use methanol directly as fuel have a simple structure, ease of fuel supply and maintenance, and high energy density. Applications to small portable devices such as telephones and laptop computers are expected.

  In the case of a polymer electrolyte fuel cell that uses hydrogen as the fuel and oxygen as the oxidant, if the gas barrier property of the polymer electrolyte membrane used is low, a so-called chemical short reaction occurs due to the permeation of hydrogen and oxygen. There is a possibility that the characteristics may be deteriorated, and further, hydrogen and oxygen may cause a direct combustion reaction, or radicals may be generated to promote deterioration of the polymer electrolyte membrane or the membrane-electrode assembly. Therefore, as a characteristic of the polymer electrolyte membrane to be used, in addition to proton conductivity, a barrier property against hydrogen and oxygen is strongly demanded. In addition, in the case of a direct methanol fuel cell using methanol as a fuel, it is regarded as a problem that methanol permeation (also referred to as crossover) of the polymer electrolyte membrane is large, but like a solid polymer fuel cell, The permeation of oxygen through the polymer electrolyte membrane promotes the deterioration of the polymer electrolyte membrane and membrane-electrode assembly, and the permeated oxygen and methanol react to form harmful by-products such as formaldehyde. May also occur. Therefore, as a characteristic of the polymer electrolyte membrane to be used, in addition to proton conductivity and methanol blocking property, oxygen blocking property is strongly required.

  Perfluorocarbon sulfonic acid membranes typified by Nafion (a registered trademark of Nafion, DuPont, the same applies below) are used as polymer electrolyte membranes for polymer electrolyte fuel cells and direct methanol fuel cells. It is widely studied because of its excellent chemical stability such as acid resistance and oxidation resistance. The hydrogen gas barrier property is also not sufficient, although it has been studied in Patent Documents 1 and 2, for example, but there is a strong demand for a thin polymer electrolyte membrane.

From the above, polymer electrolyte membranes that are inexpensive and have excellent characteristics are desired, but those that satisfy them have not yet been developed in the prior art.
JP-A-6-342665 JP 2002-313365 A

  The object of the present invention has been made in view of the above problems, and is to provide a polymer electrolyte membrane that is excellent in proton conductivity, hydrogen barrier properties, and oxygen barrier properties. Another object of the present invention is to provide a polymer electrolyte fuel cell or a direct methanol fuel cell that can exhibit excellent power generation characteristics.

  The above problems can be solved by the following polymer electrolyte membrane.

A first aspect of the present invention is a polymer electrolyte membrane containing a sulfonic acid group and a hydrocarbon polymer compound, and has a hydrogen permeability coefficient of 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ^{2 at} 23 ° C. (S · cmHg) or less.

A second aspect of the present invention is a polymer electrolyte membrane having a hydrogen permeability coefficient of 3.0 × 10 ⁻⁹ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C.

  3rd of this invention is a polymer electrolyte membrane in any one of Claim 1 or 2 whose hydrogen permeation coefficient in 80 degreeC of the said polymer electrolyte membrane is 7 times or less of the hydrogen permeation coefficient in 23 degreeC. .

A fourth aspect of the present invention is a polymer electrolyte membrane containing a sulfonic acid group and a hydrocarbon polymer compound, and has an oxygen permeability coefficient of 5.0 × 10 ⁻¹¹ cm ³ · cm / (cm ^{2 at} 23 ° C. (S · cmHg) or less.

The fifth aspect of the present invention is the polymer electrolyte membrane according to claim 4, wherein the oxygen permeability coefficient is 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C. .

  The sixth aspect of the present invention is the polymer electrolyte membrane according to claim 5, wherein the oxygen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is not more than 10 times the oxygen permeability coefficient at 23 ° C.

A seventh aspect of the present invention is a polymer electrolyte membrane containing a sulfonic acid group and a hydrocarbon polymer compound, and has a hydrogen permeability coefficient of 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ^{2 at} 23 ° C. S · cmHg) or less, and the oxygen permeability coefficient is 5.0 × 10 ⁻¹¹ cm ³ · cm / (cm ² · s · cmHg) or less at 23 ° C.

According to an eighth aspect of the present invention, the hydrogen permeability coefficient is 3.0 × 10 ⁻⁹ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C., and the oxygen permeability coefficient is 5 at 80 ° C. The polymer electrolyte membrane according to claim 7, which is 0.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less.

  According to a ninth aspect of the present invention, the hydrogen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is not more than 7 times the hydrogen permeability coefficient at 23 ° C., and the oxygen permeability coefficient at 80 ° C. is 10 times the oxygen permeability coefficient at 23 ° C. 9. The polymer electrolyte membrane according to claim 7, wherein the polymer electrolyte membrane is not more than double.

  The tenth aspect of the present invention is the polymer electrolyte membrane according to any one of claims 1 to 4, wherein the hydrocarbon polymer compound is polyphenylene sulfide.

  The eleventh aspect of the present invention is the polymer electrolyte membrane according to any one of claims 1 to 10, wherein the ion exchange capacity of the polymer electrolyte membrane is 1 to 3 meq / g.

  A twelfth aspect of the present invention is the polymer electrolyte membrane according to any one of claims 1 to 11, which is produced by a manufacturing method including a drying step in which a tension of 0.001 MPa to 30 MPa is applied at the end of drying. A polymer electrolyte membrane.

  A thirteenth aspect of the present invention is a polymer electrolyte fuel cell using the polymer electrolyte membrane according to any one of claims 1 to 12.

  A fourteenth aspect of the present invention is a direct methanol fuel cell using the polymer electrolyte membrane according to any one of claims 1 to 12.

  According to the present invention, a polymer electrolyte membrane excellent in proton conductivity, hydrogen barrier property, and oxygen barrier property can be obtained. Furthermore, a polymer electrolyte fuel cell or a direct methanol fuel cell using these polymer electrolyte membranes can exhibit excellent power generation characteristics.

  That is, the polymer electrolyte membrane of the present invention is a polymer electrolyte membrane containing a sulfonic acid group and a hydrocarbon polymer compound, and is used as hydrogen used as a fuel for a solid polymer fuel cell and as an oxidizing agent. The permeation coefficient of oxygen is not more than a predetermined value. In the present invention, the hydrogen permeability coefficient and the oxygen permeability coefficient can be measured by a method based on JIS K7126. Specifically, an isobaric method for supplying hydrogen or oxygen as a measurement gas to one side of a cell separated by a polymer electrolyte membrane and quantifying the amount of measurement gas permeated into the inert gas supplied to the other cell, A differential pressure method for quantifying the amount of measurement gas that has permeated while reducing the pressure of the other can be applied. The amount of gas that has permeated through the membrane may be quantified with a gas chromatograph or the like.

In the present invention, the hydrogen permeability coefficient at 23 ° C. of the polymer electrolyte membrane is preferably 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less. More preferably, it is 3.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less. Most preferably, it is 2.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less. If the hydrogen permeation coefficient is larger than this range, hydrogen as a fuel will easily pass through the polymer electrolyte membrane from the anode side to the cathode side, resulting in a decrease in hydrogen utilization and energy efficiency due to fuel waste, hydrogen crossover. There is a risk that the cell voltage may be reduced by the deterioration of the membrane-electrode assembly due to direct combustion reaction with oxygen on the cathode side. In the present invention, as the hydrogen permeation coefficient at 23 ° C. becomes a more preferable range or the most preferable range, a solid polymer fuel cell or a direct methanol fuel cell using these polymer electrolyte membranes is actually used. There is a tendency that the durability at the time is greatly improved.

In general, the gas permeability coefficient tends to increase with the measurement temperature. The polymer electrolyte fuel cell, which is the main use of the polymer electrolyte membrane, has different temperatures when it is stopped, at startup, during steady operation, when the load fluctuates, and so on. At that time, if the hydrogen permeability coefficient shows a tendency to increase rapidly at 80 ° C in the vicinity of the actual operating temperature range, or if the dependence on temperature is strong, it may cause performance fluctuations of the fuel cell itself, and control is difficult. There is a risk of becoming. Accordingly, in the present invention, the hydrogen permeability coefficient at 80 ° C. is preferably 3.0 × 10 ⁻⁹ cm ³ · cm / (cm ² · s · cmHg) or less. Further, the hydrogen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is preferably 7 times or less than the hydrogen permeability coefficient at 23 ° C.

In the present invention, the oxygen permeability coefficient of the polymer electrolyte membrane at 23 ° C. is preferably 5.0 × 10 ⁻¹¹ cm ³ · cm / (cm ² · s · cmHg) or less. More preferably, it is 1.0 × 10 ⁻¹¹ cm ³ · cm / (cm ² · s · cmHg) or less. Most preferably, it is 5.0 × 10 ⁻¹² cm ³ · cm / (cm ² · s · cmHg) or less. When the oxygen permeability coefficient is larger than this range, oxygen as an oxidant easily passes through the polymer electrolyte membrane from the cathode side to the anode side, and the oxidant utilization rate and energy efficiency decrease due to oxidant waste, There is a possibility that the cell voltage is lowered due to oxygen crossover, and the membrane-electrode assembly is deteriorated due to direct combustion reaction with oxygen on the anode side. In addition, when alcohols such as methanol are used as fuel, harmful by-products such as formaldehyde may be generated even when not operating. In the present invention, as the oxygen permeation coefficient at 23 ° C. becomes a more preferable range or the most preferable range, a solid polymer fuel cell or a direct methanol fuel cell using these polymer electrolyte membranes is actually used. There is a tendency that the durability at the time is greatly improved. In addition, when these polymer electrolyte membranes are used directly in a methanol fuel cell, there is a tendency to drastically reduce the generation of harmful by-products such as formaldehyde during no operation.

Furthermore, as in the case of hydrogen, the oxygen permeability coefficient tends to increase rapidly at 80 ° C. in the vicinity of the actual operating temperature range, or if the dependence on temperature is strong, Or it may be difficult to control. Accordingly, in the present invention, the oxygen permeability coefficient is preferably 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C. Furthermore, the oxygen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is preferably 10 times or less than the oxygen permeability coefficient at 23 ° C.

Assuming that the polymer electrolyte membrane of the present invention is used as an electrolyte membrane of a polymer electrolyte fuel cell, the polymer electrolyte membrane of the present invention is a polymer electrolyte containing a sulfonic acid group and a hydrocarbon polymer compound. A membrane having a hydrogen permeability coefficient of 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less at 23 ° C. and an oxygen permeability coefficient of 5.0 × 10 5 at 23 ° C. ^-11 cm ³ · cm / (cm ² · s · cmHg) or less is preferable. The hydrogen permeability coefficient is 3.0 × 10 ⁻⁹ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C., and the oxygen permeability coefficient is 5.0 × 10 ^{− at} 80 ° C. It is preferably ¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less. Further, the hydrogen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is not more than 7 times the hydrogen permeability coefficient at 23 ° C., and the oxygen permeability coefficient at 80 ° C. is not more than 10 times the oxygen permeability coefficient at 23 ° C. Is preferred. By setting the hydrogen permeation coefficient and oxygen permeation coefficient of the polymer electrolyte membrane within the above ranges, the utilization rate of fuel and oxidant and the energy efficiency of the system are high, the cell voltage is not decreased by gas crossover, and hydrogen and oxygen are reduced. Thus, it is possible to obtain a polymer electrolyte fuel cell in which the membrane-electrode assembly is hardly deteriorated due to the direct combustion reaction, the performance fluctuation due to the change in the gas permeation amount due to the operating conditions is small, and the system control is easy.

  Examples of a method for imparting proton conductivity to the polymer electrolyte membrane include a method of introducing a proton conductive substituent and a method of combining a proton conductive material. Considering the ease of obtaining a polymer electrolyte membrane, a method of introducing proton conductive substitution is preferable. Examples of proton conductive substituents include sulfonic acid groups, phosphoric acid groups, carboxylic acid groups, and phenolic hydroxyl groups, but the proton conductivity of the polymer electrolyte membrane and the ease of introduction of the proton conductive substituents can be listed. In consideration, a sulfonic acid group is preferable. Examples of hydrocarbon polymer compounds that can be used in the present invention include polyacrylamide, polyacrylonitrile, polyaryl ether sulfone, poly (allyl phenyl ether), polyethylene oxide, polyether ether sulfone, polyether ketone, polyether ketone ketone, Polyvinyl chloride, poly (diphenylsiloxane), poly (diphenylphosphazene), polysulfone, polyparaphenylene, polyvinyl alcohol, poly (phenylglycidyl ether), poly (phenylmethylsiloxane), poly (phenylmethylphosphazene), Polyphenylene oxide, polyphenylene sulfoxide, polyphenylene sulfide sulfone, polyphenylene sulfone, polybenzimidazole, polybenzoxazole, polybenzothi Sol, poly (α-methylstyrene), polystyrene, styrene- (ethylene-butylene) styrene copolymer, styrene- (polyisobutylene) -styrene copolymer, poly1,4-biphenylene ether ether sulfone, polyarylene ether sulfone , Polyetherimide, cyanate ester resin, polyethylene, polypropylene, polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polyphenylene sulfide, polyether ether ketone, polyether nitrile and the like. Among them, polyphenylene sulfide is preferable in consideration of proton conductivity, hydrogen barrier property and oxygen barrier property, chemical / thermal stability, handling property, industrial availability and the like of the polymer electrolyte membrane.

  Specifically, the polyphenylene sulfide is composed of a repeating structural unit represented by the following chemical formula (1).

-[Ar-S] _n- Chemical formula (1)
[Wherein Ar is a divalent aromatic unit represented by the following chemical formulas (2) to (4), and n is an integer of 1 or more]

また前記ポリフェニレンサルファイドのＡｒの一部に、必要に応じて以下の構造単位を含有してもよい。
（１）芳香族単位の水素原子の一部がアルキル基、フェニル基、アルコキシル基、ニトロ基およびハロゲン基からなる群から選択される少なくとも１つの置換基で置換されたもの。
（２）３官能フェニルスルフィド単位。
（３）架橋または分岐単位。

Moreover, you may contain the following structural units in part of Ar of the said polyphenylene sulfide as needed.
(1) A part of hydrogen atoms of an aromatic unit is substituted with at least one substituent selected from the group consisting of an alkyl group, a phenyl group, an alkoxyl group, a nitro group and a halogen group.
(2) Trifunctional phenyl sulfide unit.
(3) Cross-linked or branched units.

  As a result, the polymer electrolyte membrane has excellent chemical and thermal stability, handling properties, productivity, etc. in addition to the aforementioned proton conductivity, hydrogen barrier properties, methanol barrier properties, etc., which are the required properties of polymer electrolyte membranes. Is obtained.

  Further, the chemical composition of the hydrocarbon polymer compound film usable in the present invention may be a single composition of the above hydrocarbon polymer compound or selected from the above hydrocarbon polymer compounds. Two or more blend compositions may be used. When composed of two or more blended hydrocarbon polymer compounds, the physical morphology (morphology) and chemical microscopic properties in the membrane differ from the polymer electrolyte membranes composed of a single hydrocarbon polymer compound. Since it is also expected to have properties, it is preferable because it is expected to have a lower oxygen permeability coefficient and a lower hydrogen permeability coefficient than a polymer electrolyte membrane made of a hydrocarbon polymer compound having a single composition. .

  In the present invention, the polymer electrolyte membrane preferably has an ion exchange capacity of 1 to 3 meq / g. If the ion exchange capacity is lower than this range, the proton conductivity of the polymer electrolyte membrane tends to be insufficient, and the hydrogen barrier property and oxygen barrier property tend to be lower than this range. In particular, when the ion exchange capacity is larger than 3 meq / g, the hydrogen barrier property and the oxygen barrier property in a humidified atmosphere tend to be lowered, which is not preferable.

Next, the manufacturing method of the polymer electrolyte membrane of this invention is demonstrated. The polymer electrolyte membrane of the present invention can be produced mainly by the following four methods.
(1) A method of carrying out a polymerization reaction using a monomer containing a sulfonic acid group as a starting material to obtain a polymer compound containing sulfonic acid, and then forming a film from the organic solvent solution by a casting method.
(2) A method of converting a sulfonic acid group precursor into a sulfonic acid group by obtaining a polymer compound containing a sulfonic acid group precursor and then forming a film from the melt extrusion method or an organic solvent solution thereof by a casting method.
(3) A method in which a sulfonic acid group is introduced into a hydrocarbon polymer compound by a known sulfonation method, and then a film is formed from the organic solvent solution by a casting method.
(4) A method of obtaining a hydrocarbon polymer film containing a sulfonic acid group by producing a film comprising a hydrocarbon polymer compound and then immersing the film in an organic solvent solution containing a sulfonating agent.

  In the polymer electrolyte membrane of the present invention, a method suitable for the hydrocarbon polymer compound to be used may be appropriately selected from the above four methods and used. For example, in the case of polyphenylene sulfide which is preferable as a hydrocarbon polymer compound used in the polymer electrolyte membrane of the present invention, polymerization from a sulfonic acid group-containing monomer is difficult, and polyphenylene sulfide is insoluble in a solvent. In addition, after preparing a film of polyphenylene sulfide by a melt extrusion method in advance, a known sulfonating agent such as chlorosulfonic acid, fuming sulfuric acid, sulfur trioxide, concentrated sulfuric acid and methylene chloride, 1,2-dichloroethane, 1-chlorobutane, etc. It is possible to introduce sulfonic acid groups by immersing the polyphenylene sulfide film in a mixed solution composed of an organic solvent such as a halogenated hydrocarbon compound as a representative. In actual use, in order to hydrolyze the sulfonic acid group precursor and to remove unnecessary sulfonating agent and solvent, it can be used after being dipped in water, washed and dried.

  The polymer electrolyte membrane thus obtained contains a large amount of water because it contains a hydrophilic sulfonic acid group, and tends to shrink with dehydration during drying. Therefore, in order to obtain a polymer electrolyte membrane with few appearance defects such as wrinkles and crimps and little variation in performance due to thickness unevenness, for example, a tension of 0.001 MPa to 30 MPa is applied at the end of drying. It is preferable. In the case of drying in a batch system, a method of fixing to a certain frame body such as fixing to a pin and drying is also preferable.

  As will be described later in the examples of the present invention, a drying process in which a tension of 0.001 MPa to 30 MPa is applied at the end of drying rather than a polymer electrolyte membrane produced by a production method including a drying process without tension. By using a polymer electrolyte membrane produced by a production method including hydrogen, the hydrogen barrier property is increased (hydrogen permeability coefficient is decreased) and the oxygen barrier property is increased (oxygen permeability coefficient is decreased). ing. Therefore, one mode for realizing the hydrogen permeability coefficient and / or oxygen permeability coefficient described in the claims is to use a polymer electrolyte membrane having a tension of 0.001 MPa to 30 MPa at the end of drying. is there.

  In the present invention, the drying process in which tension is applied to the membrane at the end of drying means that tension is applied in the direction of the surface of the membrane at the end of drying, that is, in a direction substantially horizontal to the membrane surface. As a result, stress is applied in the direction opposite to the shrinkage in the dimensional direction of the film, so that distortion such as wrinkles, blisters, and irregularities is less likely to occur, which is preferable.

  In the present invention, the tension at the end of drying when the polymer electrolyte membrane is completed is defined, and the initial stage of drying is not defined at all. However, it goes without saying that it is necessary to start drying in a situation where tension is applied at the end of drying. The presence or absence of tension in the initial stage of drying needs to be appropriately set according to the shrinkage rate depending on the type of film to be used and the mechanical characteristics at the drying stage. For example, when there is no tension in the initial stage of drying, it is possible that the film is slackened in the direction in which gravity is applied to the center portion of the film while holding the end portion of the film. However, it goes without saying that even when the film is slack, it is within a range in which the film can be held and transported.

  Various methods can be selected as a method for realizing a state in which the film is tensioned at the end of drying, and is not particularly limited. For example, fix the peripheral edge of the film or a part or all of the opposite sides of the film with a scissor jig (such as a clip) or a stab jig (such as a pin). Tension can be applied to the membrane by pulling the jig with tension such as rubber or spring, or mechanically applying a predetermined tension. As a result, the occurrence of distortion such as wrinkles, blisters, and irregularities due to film shrinkage due to drying can be suppressed. When a film of an arbitrary size is dried in a batch system, it is preferable to apply tension at the end of drying from all directions of the peripheral edge of the film. Moreover, when drying a film | membrane continuously, you may apply a tension | tensile_strength separately in the width direction, applying a tension | tensile_strength in a take-off direction.

  In the present invention, the membrane can be fixed to the frame. In that case, fixing the film to the frame means fixing the peripheral part of the film or a part or all of the opposite sides of the film with the frame. As a result, as the film shrinks in the dimensional direction during the drying stage, tension is applied substantially in the direction of the film surface, that is, in a direction substantially horizontal to the film surface, and distortion such as wrinkles, blisters, and unevenness occurs. It becomes difficult and preferable. Depending on the shrinkage rate depending on the type of film used and the mechanical characteristics in the drying stage, the film shrinks significantly, and the mechanical characteristics of the film may not be able to withstand the stress. In such a case, it is an example of a preferable embodiment to use a frame having a structure in which the frame can be changed according to the tension.

  As described above, in one embodiment of the present invention, the tension applied to the film in the present invention is arbitrary as long as a tension of 0.001 MPa to 30 MPa is applied at the end of drying. At the end of drying, it should be above the tension at which tension is applied to the membrane and less than the mechanical strength of the membrane. In general, the value of tension at the end of drying is in the range of 0.001 MPa to 30 MPa, more preferably 0.005 MPa. It is in the range of ˜20 MPa, more preferably in the range of 0.01 MPa to 10 MPa. If the tension at the end of drying exceeds 30 MPa, the film may be broken. When the tension at the end of drying is less than 0.001 MPa, distortion such as wrinkles, blisters, and unevenness may occur.

  When the membrane is fixed to the frame, various methods can be selected as the method, and the method is not particularly limited. For example, a method of fixing the peripheral edge of the film or a part or all of the opposite sides of the film with a piercing jig (such as a pin), or a frame that can fix only the peripheral edge of the film. The membrane can be fixed to the frame by a sandwiching method or the like. When the exposed part of the film and the unexposed part coexist, stress concentrates on the interface between them, and the film is likely to break down. It is more preferable to fix with the frame provided with such a thing.

  Further, in the present invention, by applying a load in the thickness direction of the film and drying it, the film is prevented from being deformed in the thickness direction when the film is contracted, thereby suppressing the occurrence of distortion such as wrinkles, blisters, and irregularities. A method can also be illustrated.

  Next, the polymer electrolyte fuel cell and the direct methanol fuel cell of the present invention will be described with reference to the drawings as an example. FIG. 1 is a cross-sectional view of an essential part of a unit cell of a polymer electrolyte fuel cell or a direct methanol fuel cell according to the present invention. The polymer electrolyte membrane 1 of the present invention, the fuel electrode 8 including the catalyst layer 4 and the diffusion layer 6, and the oxidant electrode 9 including the catalyst layer 5 and the diffusion layer 7 are disposed on both sides of the polymer electrolyte membrane 1, respectively. The polymer electrolyte membrane 1, the fuel electrode 8, and the oxidizer electrode 9 are joined via the binder layers 2 and 3 as necessary to form a membrane-electrode assembly 10. Further, a separator 11 having a liquid fuel flow path 13 and a separator 12 having an oxidant flow path 14 are arranged outside thereof, and a unit cell 15 usable in the solid polymer fuel cell or direct methanol fuel cell of the present invention. Is obtained.

  As the polymer electrolyte membrane 1, the polymer electrolyte membrane described above is used. The binder layers 2 and 3 may be the same or different, and may be formed as necessary, or may not be formed. In general, perfluorocarbon sulfonic acid-based polymer compounds represented by Nafion, polyether ether ketones, polyether sulfones and polyimides containing sulfonic acid groups, known solvent-soluble polymer electrolytes are used. . These are used to bond (adhere) the polymer electrolyte membrane 1 and the catalyst layers 4 and 5. These materials are required to have proton conductivity, chemical stability, and the like in the same manner as the polymer electrolyte membrane 1 in addition to the bonding properties to the different materials.

  The catalyst layers 4 and 5 may be the same or different, and a catalyst having the ability to oxidize the fuel (hydrogen, methanol, etc.) to be used is used on one side. On the other hand, a catalyst having the reducing ability of the oxidizing agent (oxygen, air, etc.) to be used is used. Specifically, a material in which a noble metal catalyst such as platinum is supported on a conductive material having a high surface area such as carbon black, activated carbon, carbon nanohorn, or carbon nanotube is used. In particular, on the fuel electrode side, in order to suppress catalyst poisoning by carbon monoxide, aldehydes, carboxylic acids, etc., which are by-products during methanol oxidation, a composite or alloy catalyst comprising platinum and ruthenium instead of platinum. Etc. are used.

  The diffusion layers 6 and 7 may be the same or different, and a porous conductive material such as carbon paper or carbon cloth is used. These are supplied water or water generated by an electrochemical reaction and may be subjected to water repellent treatment with a fluorine-based compound such as polytetrafluoroethylene as necessary in order to prevent pores from being blocked. . Generally, on these diffusion layers 6 and 7, the catalyst layers 4 and 5 are perfluorocarbon sulfonic acid polymer compounds represented by Nafion, polyether ether ketones and polyethers containing sulfonic acid groups. A fuel-soluble polymer electrode such as sulfone or polyimide is used as a binder, and a fuel electrode 8 and an oxidizer electrode 9 are prepared and used. As the fuel electrode 8 and the oxidant electrode 9, a commercially available catalyst-carrying gas diffusion electrode (manufactured by E-TEK, Inc., USA) may be used.

  The manufacturing method of the membrane-electrode assembly 10 in the present invention can be selected from known or arbitrary methods. For example, after applying an organic solvent solution of the constituent materials of the binders 2 and 3 on the catalyst layers 4 and 5 of the catalyst-carrying gas diffusion electrodes 8 and 9 as necessary, a solvent is added as necessary. It removes and arrange | positions on both surfaces of the polymer electrolyte membrane 1. FIG. Thereafter, using a press machine such as a hot press machine or a roll press machine, the membrane-electrode assembly 10 can be prepared by hot pressing generally at a press temperature of about 120 to 250 ° C. If necessary, the membrane-electrode assembly 10 may be prepared without using the binders 2 and 3.

  The polymer electrolyte fuel cell or direct methanol fuel cell of the present invention may be used alone or in a stack to form a stack, and a fuel cell system incorporating them may be used.

  Further, a direct methanol fuel cell using the polymer electrolyte membrane of the present invention will be described with reference to the drawings as an example.

  FIG. 2 is a cross-sectional view of a main part of a direct methanol fuel cell including the polymer electrolyte membrane 1 of the present invention. The required number of membrane-electrode assemblies 10 are arranged in a plane on both sides of a fuel (methanol or methanol aqueous solution) tank 16 having a function of filling and supplying fuel (methanol or methanol aqueous solution). Further, a support body 17 in which an oxidant flow path 14 is formed is disposed on the outside thereof, and a cell and a stack of a direct methanol fuel cell are configured by being sandwiched between them.

  Besides the above examples, the polymer electrolyte membrane of the present invention is disclosed in JP 2001-313046, JP 2001-313047, JP 2001-93551, JP 2001-93558, JP 2001-93561, JP-A-2001-102069, JP-A-2001-102070, JP-A-2001-283888, JP-A-2000-268835, JP-A-2000-268836, JP-A-2001-2001. It can be used as a polymer electrolyte membrane of a direct methanol fuel cell, which is known in Japanese Patent No. 283892.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples, In the range which does not change the summary, it can change suitably.

(Example 1)
<Preparation of polymer electrolyte membrane>
In a glass container, 578 g of 1-chlorobutane and 8.67 g of chlorosulfonic acid were weighed to prepare a chlorosulfonic acid solution. 1.34 g of a polyphenylene sulfide film (manufactured by Toray Industries, Inc., trade name: Torelina, thickness: 25 μm) was weighed, immersed in a chlorosulfonic acid solution, and allowed to stand at room temperature for 20 hours (the amount of chlorosulfonic acid added was polyphenylene sulfide) Of 6 equivalents of aromatic units). After standing at room temperature for 20 hours, the polyphenylene sulfide film was recovered and washed with ion exchange water until neutral.

  The cleaned polyphenylene sulfide film is not fixed with a frame or the like, and is adjusted to a relative humidity of 98%, 80%, 60% and 50% in a thermo-hygrostat adjusted to 23 ° C., respectively. The film was left standing for a minute and dried to obtain a polymer electrolyte membrane (80 mm × 80 mm, thickness: 45 μm) composed of a polyphenylene sulfide membrane into which sulfonic acid groups had been introduced (hereinafter, sulfonated polyphenylene sulfide membrane).

<Measurement method of ion exchange capacity>
A polymer electrolyte membrane (about 10 mm × 40 mm) was immersed in 20 mL of a saturated aqueous sodium chloride solution at 25 ° C., and reacted in a water bath at 60 ° C. for 3 hours. After cooling to 25 ° C., the membrane was thoroughly washed with ion exchanged water, and all of the saturated aqueous sodium chloride solution and the washing water were collected. To this recovered solution, a phenolphthalein solution was added as an indicator, and neutralization titration was performed with a 0.01N sodium hydroxide aqueous solution to calculate the ion exchange capacity.

  The results are shown in Table 1.

＜プロトン伝導度の測定方法＞
イオン交換水中に保管した高分子電解質膜（約１０ｍｍ×４０ｍｍ）を取り出し、膜表面の水をろ紙で拭き取った。２極非密閉系のテフロン（登録商標）製のセルに膜を設置し、さらに白金電極を電極間距離３０ｍｍとなるように、膜表面（同一側）に設置した。２３℃での膜抵抗を、交流インピーダンス法（周波数：４２Ｈｚ〜５ＭＨｚ、印可電圧：０．２Ｖ）により測定し、プロトン伝導度を算出した。

<Measurement method of proton conductivity>
A polymer electrolyte membrane (about 10 mm × 40 mm) stored in ion-exchanged water was taken out, and water on the membrane surface was wiped off with a filter paper. The membrane was installed in a cell made of Teflon (registered trademark) in a bipolar non-sealing system, and a platinum electrode was further installed on the membrane surface (on the same side) so that the distance between the electrodes was 30 mm. The membrane resistance at 23 ° C. was measured by an AC impedance method (frequency: 42 Hz to 5 MHz, applied voltage: 0.2 V), and proton conductivity was calculated.

  The results are shown in Table 1.

<Method for measuring methanol permeability coefficient>
In a 25 ° C. environment, ion exchange water and a methanol aqueous solution having a predetermined concentration were isolated with a polymer electrolyte membrane using a membrane permeation experiment apparatus manufactured by Beadrex. A solution containing methanol permeated to the ion-exchanged water after a predetermined time was collected, and the amount of methanol permeated with a gas chromatograph was quantified. From this quantitative result, the methanol permeation rate was determined, and the methanol permeation coefficient was calculated. The methanol permeability coefficient was calculated according to the following formula 1.

結果を表１に示す。

The results are shown in Table 1.

<Measurement method of gas permeability coefficient>
The gas permeation coefficient at a predetermined temperature of hydrogen and oxygen was measured by a differential pressure method by a method based on JIS K7126. The permeation area was 1.52 × 10 ⁻³ m ^2, and a gas chromatograph was used for gas quantification.

  The results are shown in Tables 2 and 3.

（実施例２）
洗浄後のポリフェニレンサルファイドフィルムの四辺をピンからなる枠体に固定して、乾燥終了時に概ね０．３ＭＰａにしてフィルムを乾燥した以外は、実施例１と同様にした。これにより、スルホン酸基が導入されたポリフェニレンサルファイド膜（以下、スルホン化ポリフェニレンサルファイド膜）からなる高分子電解質膜（８０ｍｍ×８０ｍｍ、厚み：４２μｍ）を得た。なお、本実施例に先立ち予備検討として、張力の条件を探索する目的で、同様の実験を数回繰り返した後に、できあがる厚みがほぼ一定であることを確かめながら、乾燥終了時の張力が概ね０．３ＭＰａであるような条件を探索した。乾燥終了時の張力は、枠体に設置したバネ秤の表示数値を、できあがったフィルムの厚みと幅で割ることで、求めた。

(Example 2)
The same procedure as in Example 1 was performed except that the four sides of the washed polyphenylene sulfide film were fixed to a frame made of pins, and the film was dried at about 0.3 MPa at the end of drying. As a result, a polymer electrolyte membrane (80 mm × 80 mm, thickness: 42 μm) made of a polyphenylene sulfide membrane into which a sulfonic acid group was introduced (hereinafter referred to as a sulfonated polyphenylene sulfide membrane) was obtained. As a preliminary study prior to this example, for the purpose of searching for the tension condition, after repeating the same experiment several times, it was confirmed that the resulting thickness was almost constant, and the tension at the end of drying was approximately 0. A condition of .3 MPa was searched. The tension at the end of drying was obtained by dividing the indicated value of the spring balance installed in the frame by the thickness and width of the finished film.

  The results are shown in Tables 1-3.

<Preparation of membrane-electrode assembly>
An anode catalyst sheet was prepared as follows. Pt: Ru: C = 27: 13: 60 (weight ratio) platinum-ruthenium-supported carbon catalyst, distilled water and a catalyst ink composed of 5 wt% Nafion solution (Aldrich) were prepared and transferred from Teflon (registered trademark). The catalyst ink was applied to the sheet. While repeating the weight measurement and drying, the application of the catalyst ink was repeated until the amount of platinum reached 1 mg / cm ² . As the cathode catalyst sheet, a platinum-supported carbon catalyst of Pt: C = 50: 50 (weight ratio) was used instead of the platinum-ruthenium-supported carbon catalyst of Pt: Ru: C = 27: 13: 60 (weight ratio). Except for this, it was the same as the anode catalyst sheet.

  An anode catalyst sheet and a cathode catalyst sheet were placed on both sides of the polymer electrolyte membrane made of the sulfonated polyphenylene sulfide obtained in Example 2, and heated and compressed (180 ° C. for 10 minutes), and then the transfer sheet was peeled off. A catalyst layer was formed on both sides of the polymer electrolyte membrane.

<Evaluation of power generation characteristics of direct methanol fuel cell>
Diffusion layers made of carbon paper were disposed on both sides of the membrane-electrode assembly obtained by the above method and incorporated into a single fuel cell (power generation region: 5 cm ² ). As a fuel, 0.5 mL / min of an aqueous methanol solution with a predetermined concentration is supplied, and 124 mL / min of air that is fully humidified at 60 ° C. is supplied as an oxidizer. It was.

  The results are shown in FIGS.

(Example 3)
Example 1 except that the amount of 1-chlorobutane was 746 g, the amount of chlorosulfonic acid was 14.93 g, and the polyphenylene sulfide film (trade name: Torelina, thickness: 50 μm) was 1.73 g. A polymer electrolyte membrane was prepared (the amount of chlorosulfonic acid added was 8 equivalents relative to the aromatic unit of polyphenylene sulfide) to obtain a polymer electrolyte membrane (80 mm × 80 mm, thickness: 95 μm) composed of a sulfonated polyphenylene sulfide membrane. It was.

  The same procedure as in Example 1 was conducted except that this sulfonated polyphenylene sulfide membrane was used as the polymer electrolyte membrane.

  The results are shown in Tables 1-3.

Example 4
A polymer electrolyte membrane was obtained in the same manner as in Example 3, except that the four sides of the washed polyphenylene sulfide film were fixed to a frame made of pins and the film was dried at 0.2 MPa at the end of drying. As a result, a polymer electrolyte membrane (80 mm × 80 mm, thickness: 90 μm) made of a polyphenylene sulfide membrane into which a sulfonic acid group was introduced (hereinafter referred to as a sulfonated polyphenylene sulfide membrane) was obtained. As a preliminary study prior to this example, for the purpose of searching for the tension condition, after repeating the same experiment several times, it was confirmed that the resulting thickness was almost constant, and the tension at the end of drying was approximately 0. A condition of .2 MPa was searched. The tension at the end of drying was determined by dividing the indicated value of the spring balance installed on the frame by the thickness and width of the finished film.

  The results are shown in Tables 1-3.

  Furthermore, a membrane-electrode assembly was obtained in the same manner as in Example 2 except that the polymer electrolyte membrane obtained by the above method was used.

  The results are shown in FIGS.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that Nafion (registered trademark) 115 manufactured by DuPont was used as the polymer electrolyte membrane.

  The results are shown in Tables 1 to 3 and FIGS.

  From the comparison of proton conductivity in Examples 1 to 4 and Comparative Example 1 in Table 1, the polymer electrolyte membrane of the present invention is equivalent to Nafion (registered trademark) which is a known electrolyte membrane for a polymer electrolyte fuel cell. The proton conductivity was shown, and it was revealed that the polymer has proton conductivity that can be used as a polymer electrolyte membrane of a solid polymer fuel cell or a direct methanol fuel cell.

  Moreover, from the comparison of the methanol permeability coefficients of Examples 1 to 4 and Comparative Example 1 in Table 1, the polymer electrolyte membrane of the present invention was obtained from Nafion (registered trademark), which is a known electrolyte membrane for a polymer electrolyte fuel cell. In addition, when it is used as a polymer electrolyte membrane for a direct methanol fuel cell, the power generation characteristics tend not to deteriorate even when the concentration of the methanol aqueous solution is high. It has been clarified that even when the film thickness is reduced, the methanol barrier property equivalent to that of Nafion (registered trademark) can be maintained. Furthermore, from the comparison of the proton conductivity and methanol permeability coefficient of Examples 1 and 2 and Examples 3 and 4 in Table 1, when the method of fixing to a frame and drying at the time of membrane production was applied, the proton conductivity As a result, the methanol permeation coefficient did not increase and there was no tendency to increase the methanol permeability coefficient.

  From comparison between Examples 1 to 4 and Comparative Example 1 in Table 2, the hydrogen permeation coefficient at 23 ° C. of the polymer electrolyte membrane of the present invention is Nafion (registered trademark), which is a known electrolyte membrane for polymer electrolyte fuel cells. It was shown to be about 1/4 to 1/2 of. Further, from the comparison between Examples 1 and 2 and Tables 3 and 4 in Table 2, when the polymer electrolyte membrane was dried, the case where the four sides were fixed with a frame made of pins was accompanied by an increase in film thickness uniformity. It was shown that since the unevenness of the film thickness is reduced, the portion where the film thickness is relatively thin and hydrogen easily permeates is reduced, and the hydrogen permeability coefficient is reduced to about ½. That is, a polymer electrolyte membrane produced by a production method including a drying step in which a tension of 0.001 MPa to 30 MPa is applied at the end of drying rather than a polymer electrolyte membrane produced by a production method including a drying step without tension. This means that the hydrogen barrier property is increased (the hydrogen permeation coefficient is decreased). Further, the comparison between Examples 2 and 4 and Comparative Example 1 in Table 2 shows that the hydrogen permeation coefficient at 80 ° C. of the polymer electrolyte membrane of the present invention is about 1/8 that of Nafion (registered trademark). It was. From the above, it has been clarified that the polymer electrolyte membrane of the present invention has excellent hydrogen barrier properties and is useful as a polymer electrolyte membrane of a solid polymer fuel cell.

  Further, from comparison between Examples 1 to 4 and Comparative Example 1 in Table 2, the oxygen permeation coefficient of the polymer electrolyte membrane of the present invention at 23 ° C. is Nafion (registered trademark) which is a known electrolyte membrane for polymer electrolyte fuel cells. ) Of about 1/7 to 1/20. Furthermore, from the comparison between Examples 1 and 2 and Tables 3 and 4 in Table 2, when the polymer electrolyte membrane was dried, the four sides fixed with a frame made of pins were accompanied by an increase in film thickness uniformity. It was shown that since the non-uniformity of the film thickness is reduced, the portion where the film thickness is relatively thin and oxygen easily permeates is reduced, and the oxygen transmission coefficient is reduced to about 1/4. That is, a polymer electrolyte membrane produced by a production method including a drying step in which a tension of 0.001 MPa to 30 MPa is applied at the end of drying rather than a polymer electrolyte membrane produced by a production method including a drying step without tension. This means that the oxygen barrier property is increased (the oxygen permeability coefficient is decreased). In addition, the comparison between Examples 2 and 4 and Comparative Example 1 in Table 2 shows that the oxygen permeability coefficient of the polymer electrolyte membrane of the present invention at 80 ° C. is about 1/40 of that of Nafion (registered trademark). It was. From the above, it was revealed that the polymer electrolyte membrane of the present invention has excellent oxygen barrier properties and is useful as a polymer electrolyte membrane for solid polymer fuel cells and direct methanol fuel cells.

  From the comparison between Examples 2 and 4 and Comparative Example 1 in Table 3, the hydrogen barrier property and oxygen barrier property at 80 ° C. of the polymer electrolyte membrane of the present invention are about 4 times and 6 times the barrier property at 23 ° C., respectively. It was shown that the increase was less than 9 times (hydrogen) and 12 times (oxygen) of Nafion (registered trademark), which is a known electrolyte membrane for a polymer electrolyte fuel cell. Therefore, the gas barrier property of the polymer electrolyte membrane of the present invention is less dependent on temperature than Nafion (registered trademark), and is a gas associated with the operating conditions of a solid polymer fuel cell and a direct methanol fuel cell. It became clear that there was little fluctuation | variation of interruption | blocking property.

From the comparison between Examples 2 and 4 and Comparative Example 1 in FIG. 3, the polymer electrolyte membrane of the present invention is a known electrolyte membrane for a polymer electrolyte fuel cell with a cell voltage at a current density of 50 mA / cm ^2. As compared with about 0.11 V of a certain Nafion (registered trademark), the cell voltages were about 0.39 V and 0.16 V, respectively. Moreover, the cell voltage higher than Nafion (trademark) was shown in all the measured current density areas. Furthermore, from the comparison between Examples 2 and 4 and Comparative Example 1 in FIG. 4, even when the concentration of the methanol aqueous solution as the fuel was measured from 4 mol / L to 8 mol / L, the current density was 50 mA / cm ^2. The cell voltage at the time showed high cell voltages of about 0.25 V and 0.21 V, respectively, compared to about 0.10 V of Nafion (registered trademark). Moreover, the cell voltage higher than Nafion (trademark) was shown in all the measured current density areas. From the above, it was revealed that when the polymer electrolyte membrane of the present invention was directly used for an electrolyte membrane of a methanol fuel cell, it had excellent power generation characteristics, and the usefulness of the present invention was shown.

It is principal part sectional drawing of an example of the unit cell of the polymer electrolyte fuel cell or direct methanol fuel cell which concerns on this invention. It is principal part sectional drawing of an example of the direct methanol fuel cell which concerns on this invention. Power generation characteristics of direct methanol fuel cell when 4 mol / L aqueous methanol solution is used as fuel Power generation characteristics of direct methanol fuel cell when 8mol / L methanol aqueous solution is used as fuel

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polymer electrolyte membrane 2 Binder layer by the side of a fuel electrode 3 Binder layer by the side of an oxidant electrode 4 Catalyst layer by the side of a fuel electrode 5 Catalyst layer by the side of an oxidant electrode 6 Diffusion layer by the side of a fuel electrode 7 Oxidant electrode Side diffusion layer 8 Fuel electrode 9 Oxidant electrode 10 Membrane-electrode assembly 11 Fuel electrode side separator 12 Oxidant electrode side separator 13 Fuel flow channel 14 Oxidant flow channel 15 Unit cell 16 Tank 17 Support

Claims (14)

A polymer electrolyte membrane comprising a sulfonic acid group and a hydrocarbon polymer compound, wherein a hydrogen permeation coefficient is 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less at 23 ° C. A polymer electrolyte membrane. ^2. The polymer electrolyte membrane according to claim 1, wherein the hydrogen permeability coefficient is 3.0 × 10 ⁻⁹ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C. ³ .   3. The polymer electrolyte membrane according to claim 1, wherein a hydrogen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is 7 times or less of a hydrogen permeability coefficient at 23 ° C. 3. A polymer electrolyte membrane comprising a sulfonic acid group and a hydrocarbon polymer compound, wherein the oxygen permeability coefficient is 5.0 × 10 ⁻¹¹ cm ³ · cm / (cm ² · s · cmHg) or less at 23 ° C. A polymer electrolyte membrane. 5. The polymer electrolyte membrane according to claim 4, wherein the oxygen permeability coefficient is 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C. 6.   6. The polymer electrolyte membrane according to claim 5, wherein the polymer electrolyte membrane has an oxygen permeability coefficient at 80 ° C. of 10 times or less of an oxygen permeability coefficient at 23 ° C. A polymer electrolyte membrane comprising a sulfonic acid group and a hydrocarbon polymer compound, wherein the hydrogen permeability coefficient is 5.0 × 10 ⁻¹⁰ cm ³ · cm / (cm ² · s · cmHg) or less at 23 ° C., And a polymer electrolyte membrane having an oxygen permeability coefficient of 5.0 × 10 ⁻¹¹ cm ³ · cm / (cm ² · s · cmHg) or less at 23 ° C. The hydrogen permeability coefficient is 3.0 × 10 ⁻⁹ cm ³ · cm / (cm ² · s · cmHg) or less at 80 ° C., and the oxygen permeability coefficient is 5.0 × 10 ⁻¹⁰ cm at 80 ° C. The polymer electrolyte membrane according to claim 7, which is ³ · cm / (cm ² · s · cmHg) or less.   8. The hydrogen permeability coefficient at 80 ° C. of the polymer electrolyte membrane is 7 times or less of the hydrogen permeability coefficient at 23 ° C., and the oxygen permeability coefficient at 80 ° C. is 10 times or less of the oxygen permeability coefficient at 23 ° C. Or the polymer electrolyte membrane according to any one of 8;   The polymer electrolyte membrane according to claim 1, wherein the hydrocarbon polymer compound is polyphenylene sulfide.   The polymer electrolyte membrane according to any one of claims 1 to 10, wherein the polymer electrolyte membrane has an ion exchange capacity of 1 to 3 meq / g.   The polymer electrolyte membrane according to any one of claims 1 to 11, wherein the polymer electrolyte membrane is produced by a production method including a drying step in which a tension of 0.001 MPa to 30 MPa is applied at the end of drying.   A polymer electrolyte fuel cell using the polymer electrolyte membrane according to any one of claims 1 to 12.   A direct methanol fuel cell using the polymer electrolyte membrane according to any one of claims 1 to 12.

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