JP5589253B2 - Electrolyte membrane for polymer electrolyte fuel cell, membrane-electrode assembly using the electrolyte membrane, fuel cell using the electrolyte membrane or membrane-electrode assembly, and methods for producing them. - Google Patents

Description

  The present invention relates to an electrolyte membrane, a membrane-electrode assembly, and a fuel cell using them, which are used for a polymer electrolyte fuel cell, a direct liquid fuel cell, a direct methanol fuel cell and the like.

  In recent years, development of highly efficient and clean energy sources has been demanded from the viewpoint of environmental problems such as global warming. Fuel cells are attracting attention as one candidate for this. A fuel cell directly supplies power by supplying a fuel such as hydrogen gas or methanol and an oxidant such as oxygen to electrodes separated by an electrolyte, while oxidizing the fuel on the one hand and reducing the oxidant on the other. is there.

  Among fuel cells, in particular, polymer electrolyte fuel cells, direct liquid fuel cells, and direct methanol fuel cells are expected as one of the pillars of new energy technology. For example, a polymer electrolyte fuel cell using an electrolyte membrane made of a polymer compound having a proton-conducting functional group has features such as operation at a low temperature and reduction in size and weight. Application to consumer cogeneration systems and consumer small portable devices is under consideration. In addition, direct liquid fuel cells, especially direct methanol fuel cells that use methanol directly as fuel, have a simple structure, easy fuel supply and maintenance, and high energy density. As a replacement for lithium ion secondary batteries, it is expected to be applied to small consumer portable devices such as mobile phones and laptop computers.

  Among the fuel cell materials described above, one of the most important members is an electrolyte membrane. Various electrolyte membranes for separating such fuel and oxidant have been developed so far, and in recent years, they are composed of a polymer compound containing a proton conductive functional group such as a sulfonic acid group. Development of polymer electrolyte membranes is active. Such polymer electrolyte membranes can be used as raw materials for electrochemical elements such as humidity sensors, gas sensors, and electrochromic display elements in addition to solid polymer fuel cells, direct liquid fuel cells, and direct methanol fuel cells. Also used.

  Here, as the electrolyte membrane used in the polymer electrolyte fuel cell, there is a styrene-based cation exchange membrane developed in the 1950s, but it has poor stability in the fuel cell operating environment and has a sufficient life. No fuel cell has been produced.

  On the other hand, as an electrolyte membrane having practical stability, a perfluorocarbon sulfonic acid membrane represented by Nafion (registered trademark) has been widely studied. Perfluorocarbon sulfonic acid membranes are said to have high proton conductivity and excellent chemical stability such as acid resistance and oxidation resistance.

  However, since Nafion (registered trademark) is a fluorine-based electrolyte membrane, the raw material used is high, and a complicated manufacturing process is required, so that it is very expensive. It has also been pointed out that it is deteriorated by hydrogen peroxide generated by electrode reaction and by-product hydroxy radical. Furthermore, the permeation (also referred to as crossover) of a hydrogen-containing liquid such as methanol which is a raw material of a direct liquid fuel cell is large, and a so-called chemical short reaction occurs. As a result, cathode potential, fuel efficiency, cell characteristics and the like are lowered, and it is difficult to use as an electrolyte membrane of a direct liquid fuel cell such as a direct methanol fuel cell. Moreover, since Nafion (registered trademark) has a large morphological change, that is, swelling, the membrane itself is subjected to mechanical adaptability and may be damaged. Furthermore, since Nafion (registered trademark) has a high permeability such as a hydrogen-containing liquid, there is a concern that fuel may be lost due to crossover even when power is not generated.

  At present, various types of polymer electrolyte membranes have been proposed in order to solve the above problems. For example, Patent Document 1 and Patent Document 2 propose an electrolyte membrane that takes a form in which an electrolyte is held in a porous support such as a polymer.

  These polymer electrolyte membranes have a structure in which a porous support is filled with a polymer electrolyte as a continuous phase, and the swelling to methanol or water used as fuel is suppressed by the porous support. It is said that the transmission (crossover) is suppressed. However, since the manufacturing process is complicated, there are problems in terms of manufacturing cost and productivity. In addition, such a structure has a problem that the ratio of the electrolyte on the surface of the electrolyte membrane to be joined to the electrode is limited, and a sufficient proton conduction path cannot be formed with the electrode, so that an electrolyte-only layer can be formed on the surface layer. Although there is an example shown in the figure, there is a problem that it is basically difficult to change the composite ratio and to change the thickness of each layer.

  Patent Document 3 proposes an electrolyte membrane prepared from a polymer film having a polymer compound having an aromatic unit and a polymer compound having no aromatic unit. Although this electrolyte membrane is also said to suppress swelling and permeation (crossover) of methanol and water used as fuel, the ratio of the electrolyte on the surface of the electrolyte membrane joined to the electrode is also limited. There is a problem that a sufficient proton conduction path cannot be formed.

Patent Document 4 and Patent Document 5 each exemplify a laminated film of polyarylene electrolytes having different ion exchange capacities and a laminated film having a flexible layer on the surface. However, these are all laminated films having a single composition, and are insufficient for the problem to be solved by the present invention.
International Publication WO00 / 54351 Pamphlet JP 2006-128066 A International Publication WO06 / 019029 Pamphlet JP 2005-246800 A JP 2005-353581 A

  An object of the present invention is to provide a novel electrolyte membrane used for a polymer electrolyte fuel cell, a direct liquid fuel cell, and a direct methanol fuel cell. In other words, it is an electrolyte membrane in which the permeability of hydrogen-containing liquids such as methanol (crossover) is kept as small as possible while maintaining proton conductivity to be used as an electrolyte membrane for fuel cells, and it also forms a sufficient proton conduction path with the electrode. It is an object to provide an electrolyte membrane that can be used.

  As a result of intensive studies to solve the above problems, the present inventor is a composite electrolyte membrane composed of a polymer electrolyte and a polymer non-electrolyte, and the cross section of the electrolyte membrane is observed with a transmission electron microscope. The polymer electrolyte has a structure in which the polymer electrolyte is dispersed in a granular form in the polymer non-electrolyte, or each has a layered structure, and the polymer electrolyte has a form of 5 microns or less in the thickness direction of the membrane. Permeation of hydrogen-containing fuel components such as methanol while ensuring sufficient proton conductivity with a polymer electrolyte membrane consisting of at least two layers with a composite ratio of different polyelectrolytes / polyelectrolytes in a composite form It has been found that a polymer electrolyte membrane capable of suppressing the above-described property and capable of forming a sufficient proton conduction path with the electrode is obtained, and the present invention has been completed.

That is, the polymer electrolyte membrane of the present invention is a composite electrolyte membrane comprising a polymer electrolyte and a polymer non-electrolyte, and takes the composite form of (A) below, and is a blend of different polymer electrolytes / polymer non-electrolytes. Ri Do of at least two layers having a ratio, at least one layer is a polymer electrolyte membrane having a structure in which the polymer electrolyte is dispersed in particulate in the polymer non-electrolyte.

(A) When the cross section in the thickness direction of the electrolyte membrane is observed with a transmission electron microscope, the polymer electrolyte has a structure in which the polymer electrolyte is dispersed in a granular form in the polymer non-electrolyte, or each has a layered structure. , a contact and a polymer electrolyte is 5 microns or less in the form in the thickness direction of the film.

  In addition, the polymer electrolyte membrane of the present invention may have at least one layer composed only of the polymer electrolyte.

  By having the above-described structure, as described later, the proton conductivity can be used as an electrolyte membrane for a fuel cell, and the permeability of the hydrogen-containing liquid such as methanol (crossover) is reduced as much as possible. An electrolyte membrane capable of sufficiently forming a proton conduction path can be obtained.

  In addition, the polymer electrolyte membrane of the present invention may have a structure composed of two layers or a structure composed of three or more layers, and the blend ratio of the polymer electrolyte / polymer non-electrolyte in the surface layer may be other layers. As compared with, the ratio of the polymer electrolyte may be large. By having such a structure, it is possible to obtain a polymer electrolyte membrane with higher performance according to the specifications of the fuel cell.

  The polymer electrolyte membrane of the present invention can also be obtained by preparing a film containing a polymer compound having an aromatic unit and a polymer compound not having an aromatic unit, and sulfonating the film. Further, it can be obtained by a production method including a multilayer extrusion process. By such a manufacturing method, a target polymer electrolyte membrane can be obtained easily without the need for a special apparatus.

  In the polymer electrolyte membrane of the present invention, the polymer electrolyte has at least one polymer compound selected from the group consisting of the following (i) to (iii), or a mixture thereof with a sulfonic acid group: The structure formed by introducing may be used.

(I) at least one polymer selected from the group of polymers consisting of polystyrene, syndiotactic polystyrene, polyphenylene ether, modified polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, and polyphenylene sulfide;
(Ii) a copolymer comprising the polymer compound described in (i) above;
(Iii) A derivative of the polymer compound described in (i) and (ii) above.

  In the polymer electrolyte membrane of the present invention, the polymer non-electrolyte may contain a polymer compound having a repeating unit of the following general formula (1), or a mixture thereof.

-(CX ₁ X ₂ -CX ₃ X ₄ )-(1)
_(Wherein, X _{1 to 4} is, H, based on any one _{of CH 3, Cl, F, OCOCH} 3, CN, COOH, are selected from the group consisting of COOCH _3, and _OC 4 _{H 9, X 1~ 4} are independent of each other and may be the same or different.

  Further, the polymer electrolyte membrane of the present invention includes one polymer compound selected from the group consisting of polyethylene, polypropylene, polymethylpentene, and derivatives thereof, or a mixture thereof as a polymer non-electrolyte. May be.

  By using the above materials, it is possible to obtain a polymer electrolyte membrane that is inexpensive and excellent in chemical and thermal stability.

  Moreover, the membrane-electrode assembly according to the present invention uses the polymer electrolyte membrane according to the present invention. The membrane-electrode assembly according to the present invention includes a polymer electrolyte membrane that has high methanol barrier properties and is suppressed from swelling with respect to a hydrogen-containing liquid such as methanol, and further has sufficient proton conduction with the electrode. Since it has a path, it is particularly excellent as a membrane-electrode assembly for a polymer electrolyte fuel cell, a direct liquid fuel cell, and a direct methanol fuel cell.

  The fuel cell according to the present invention is a fuel cell (solid polymer fuel cell, direct liquid fuel cell, direct methanol fuel cell, etc.) using the polymer electrolyte membrane according to the present invention. Therefore, the fuel cell according to the present invention has a polymer electrolyte membrane having high methanol barrier properties, suppressing swelling with respect to a hydrogen-containing liquid such as methanol, and further having a sufficient proton conduction path with the electrode. And has excellent performance. In particular, the present invention is particularly preferably used for a polymer electrolyte fuel cell, a direct liquid fuel cell, and a direct methanol fuel cell.

  The polymer electrolyte membrane for a polymer electrolyte fuel cell of the present invention has a low permeability of a hydrogen-containing liquid such as methanol, while maintaining proton conductivity so that it can be used as an electrolyte membrane for a fuel cell. It is a polymer electrolyte membrane capable of forming a proton conduction path. This can be suitably used for solid polymer fuel cells, direct liquid fuel cells, and direct methanol fuel cells. Moreover, according to the present invention, it is possible to obtain a polymer electrolyte membrane excellent in processability, mechanical properties, and chemical stability in addition to the above preferred physical properties.

  Embodiments of the present invention will be described below, but the present invention is not limited thereto.

<1. Polymer Electrolyte Membrane According to the Present Invention>
The polymer electrolyte membrane according to the present invention is a composite electrolyte membrane composed of a polymer electrolyte and a polymer non-electrolyte, has a specific composite form, and has a different ratio of polymer electrolyte / polymer non-electrolyte. Further, the polymer electrolyte membrane is composed of at least two layers. Here, the polymer electrolyte is a polymer having an ion exchange group such as a carboxylic acid group, a phosphoric acid group, or a sulfonic acid group, and a polymer electrolyte for a fuel cell is currently being extensively researched. As mentioned in Non-Patent Document 1 and Non-Patent Document 2, there are various types such as fluorine-based, partially fluorine-based, and hydrocarbon-based. In the present invention, heat resistance, cost, production From the point of view of properties, it is preferable to be a hydrocarbon type, particularly an aromatic hydrocarbon type.
“Latest Fuel Cell Components” p. 33-p. 91 (issued by Technical Information Association in 2003) “Development of ion exchange membranes for polymer electrolyte fuel cells” p. 19-p. 115 (issued by 2000 CMC) The polymer electrolyte in the present invention is preferably one in which a sulfonic acid group is introduced into the following compound. In particular, a polymer compound having an aromatic unit is desirable. Examples of such a polymer compound include polyaryl ether sulfone, polyether ether sulfone, polyether ketone, polyether ketone ketone, polysulfone, polyparaphenylene, polyphenylene sulfide, polyphenylene ether, polyphenylene sulfoxide, and polyphenylene sulfide. Sulfone, polyphenylene sulfone, polybenzimidazole, polybenzoxazole, polybenzothiazole, polystyrene, syndiotactic polystyrene, polyether sulfone, poly 1,4-biphenylene ether ether sulfone, polyarylene ether sulfone, polyether imide, cyanate ester Resins, polyether ether ketones, polyesters, and copolymers of these polymer compounds, Including derivatives of these polymer compounds can be exemplified al. In particular, chemical and thermal stability, ease of introduction of proton-conductive substituents, proton conductivity of the resulting proton-conductive polymer electrolyte, and methanol blocking of the resulting proton-conductive polymer electrolyte membrane In view of properties, it is preferable to include at least one of polyphenylene sulfide, polyphenylene ether, polystyrene, syndiotactic polystyrene, polyether sulfone, and polyether ether ketone, and a block copolymer and a random copolymer.

  In addition, it is preferable that the polymer electrolyte in the polymer electrolyte membrane in the present invention has the same composition in any layer. Thereby, the adjustment of the electrolyte membrane is facilitated, and a membrane excellent in proton conductivity between layers and having little possibility of peeling between layers can be obtained.

  The polymer non-electrolyte is a polymer that does not literally have an ion exchange ability, and does not exhibit swelling as seen in a polymer electrolyte with respect to a hydrogen-containing liquid such as methanol. By combining with a polymer having such characteristics, functions such as swelling suppression and methanol permeability in the present invention can be imparted.

  Examples of such polymer non-electrolytes include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 4-methyl-1-pentene, and 5-methyl-1-heptene. Polyolefin resins such as homopolymers or copolymers of α-olefins such as vinyl chloride resins such as vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers, vinyl chloride-olefin copolymers, Examples thereof include polyamide resins such as nylon 6 and nylon 66, and mixtures thereof. In particular, compatibility and dispersibility with other polymer compound components, processability when manufacturing polymer films, handling properties of the resulting polymer films, and methanol barrier properties of the polymer electrolytes obtained from them, In consideration of thermal stability, bondability with the electrode, and the like, it is preferable to include a polymer compound represented by the following general formula (1).

-(CX ₁ X ₂ -CX ₃ X ₄ )-(1)
_(Wherein, X _{1 to 4 is, H,} CH _{3, Cl,} be any that OCOCH 3, CN, COOH, COOCH 3, and _OC 4 _{H 9,} is selected from the group consisting _{of, X 1 to 4} May be the same or different from each other)
Among such polymer compounds, industrial availability, mechanical properties and handling properties of the resulting polymer film, proton conductivity and methanol blocking properties of the resulting polymer electrolyte membrane, chemical stability, Considering bondability with the electrode, etc., it is preferable to include polyethylene and / or polypropylene.

  The composite electrolyte in the present invention is a combination of the polymer electrolyte and a polymer non-electrolyte. As the state of each component in the film, when the cross section is observed with an electron microscope, a structure in which the polymer electrolyte is dispersed in a granular form in the polymer non-electrolyte, or a structure in which each is layered And the polymer electrolyte must be in the form of 5 microns or less in the thickness direction of the membrane. By taking such a structure, the above-mentioned swelling suppression and permeation suppression with respect to methanol, water, etc. are effectively performed, and the effect which is not in the film | membrane of a single component is expressed.

  Moreover, the ratio of each component can be arbitrarily set according to the characteristics of the film and the state of lamination. That is, when the ratio of the polymer electrolyte is large, the proton conductivity is emphasized, and when the ratio of the polymer non-electrolyte is large, the swelling is suppressed and permeation suppression with respect to methanol or water is emphasized. Since the polymer electrolyte membrane in the present invention is a laminated film in which these blends are changed, an appropriate blending ratio is set depending on the thickness of each layer, usage, and the like. However, the ratio of the polymer electrolyte is preferably between 20% by weight and 80% by weight in order to express the effect of compounding on a single component membrane. However, it may be effective to set a part of the plurality of layers out of this range. For example, it is preferable to configure one or both of the surface layers with only an electrolyte because it is effective in forming a proton conduction path with a sufficient electrode, which is one of the objects of the present invention.

  The number of layers of the polymer electrolyte membrane can be appropriately set according to the purpose of use and required characteristics, but it is preferably 2 layers or 3 layers from the standpoint of manufacturing convenience. In the case of two layers, since the characteristics differ depending on each surface layer, either the anode electrode or the cathode electrode may be appropriately disposed. Since each of these electrodes is different in fuel, chemical reaction, product, etc., appropriate electrolyte membrane characteristics are also different. Therefore, an appropriate combination can be set by experimental confirmation. The case of three layers is basically the same as the case of two layers, but since the surface layer is a part that forms a proton conduction path with the electrode, generally a layer containing a large amount of polymer electrolyte is set. Is preferred.

  Various commonly used additives such as compatibilizers for improving compatibility, antioxidants for preventing resin deterioration, antistatic agents and lubricants for improving handling in film forming processes, etc. It can be used as appropriate as long as it does not affect the processing and performance of the film.

<2. Production Method for Polymer Electrolyte Membrane According to the Present Invention>
As a method for producing the polymer electrolyte membrane according to the present invention, various conventionally known methods can be used.

  Among them, a polymer compound containing an aromatic unit and a polymer compound having no aromatic unit are combined to produce a multilayer polymer film, and a proton conductive group such as a sulfonic acid group is introduced into the film. It is a method to do. By using this method, the polymer electrolyte membrane of the present invention can be obtained by a simple and efficient method using conventional equipment. Hereinafter, this method will be described in detail as an example.

  First, the manufacturing method of the polymer film as described in this invention is demonstrated. In the present invention, a known method can be used to obtain a polymer film. Examples thereof include melt extrusion molding such as inflation method and T-die method, calendar method, cast method, cutting method, emulsion method, hot press method, and the like. Furthermore, after obtaining the polymer film, a treatment such as biaxial stretching may be applied to control the molecular orientation or the like, or a heat treatment may be applied to control the crystallinity. Furthermore, it is also within the scope of the present invention to add various fillers in order to increase the mechanical strength of the film, or to form a composite with a reinforcing agent such as a glass nonwoven fabric by pressing.

  Among the above methods, productivity and mechanical properties of the resulting polymer film, ease of control of film thickness including the thickness of each layer, ease of multilayer film production, applicability to various resins, environment Considering the load on the surface, a method of manufacturing by melt extrusion is preferable. Specifically, a method of forming a film while melting and kneading the material into, for example, a T-die extruder can be applied.

  For the production of the multilayer film, it is convenient and preferable to use a generally used multilayer extrusion equipment. This is because an extruder corresponding to the number of layers is connected to a multilayer T-die, and the thickness of each layer can be adjusted by the extrusion amount of each extruder.

  Arbitrary thickness can be selected as thickness of the polymer film manufactured according to a use. For example, in consideration of reducing the internal resistance of the polymer electrolyte membrane obtained from the polymer film, the thinner the polymer film, the better. On the other hand, considering the methanol barrier property and handling property of the obtained polymer electrolyte membrane, the tear resistance at the time of joining with an electrode, etc., it may not be preferable if the thickness of the polymer film is too thin. Considering these, the thickness of the polymer film is preferably 1.2 μm or more and 350 μm or less. If the thickness of the polymer film is within the above-mentioned range, the film can be easily produced, and wrinkles are not easily generated during processing when the proton conductive group is introduced or during drying. In addition, handling is improved such that damage is unlikely to occur. In addition, the proton conductivity of the obtained polymer electrolyte membrane can be expressed within a desired range. The thickness of each layer is set to an appropriate value according to the characteristics of each layer, but the thickness of one layer is preferably in the range of 10 to 90% of the whole. Within this range, it is easy to obtain the effect of multiple layers.

  As a method for introducing a sulfonic acid group which is a proton conductive group, a known method for introducing a sulfonic acid group can be used. In particular, a method in which a polymer film is brought into contact with a sulfonic acid group introducing agent in the presence of an organic solvent is preferable because a polymer electrolyte membrane having both excellent proton conductivity and high methanol blocking property can be obtained easily and with high productivity. .

  The ion exchange capacity of the polymer electrolyte membrane derived from the content of the sulfonic acid group is preferably 0.3 meq / g or more, more preferably 0.5 meq / g or more. When the ion exchange capacity is 0.3 meq / g or more, the polymer electrolyte membrane is likely to exhibit preferable proton conductivity.

  In the present invention, by bringing the polymer film and the sulfonating agent into contact with each other in the presence of an organic solvent, the desired amount of the sulfonic acid group is reduced while suppressing the sulfonating agent from directly contacting and deteriorating the polymer film. It becomes possible to introduce.

  Examples of the sulfonating agent that can be used in the present invention include known sulfonating agents such as chlorosulfonic acid, fuming sulfuric acid, sulfur trioxide, sulfur trioxide-triethyl phosphate, concentrated sulfuric acid, and trimethylsilyl chlorosulfate. preferable. In consideration of industrial availability, ease of introduction of sulfonic acid groups, and characteristics of the obtained polymer electrolyte membrane, it is preferable to use chlorosulfonic acid alone or a mixture containing chlorosulfonic acid. That is, in the present invention, the sulfonating agent is preferably chlorosulfonic acid. This is because when the sulfonating agent is chlorosulfonic acid, a sulfonic acid group that is a proton conductive group is easily introduced, and a polymer electrolyte membrane having high proton conductivity can be easily obtained.

  The organic solvent that can be used in the above process does not cause degradation such as decomposition of the thermoplastic polymer or antioxidant in the film without decomposing the sulfonating agent, without inhibiting introduction of the sulfonic acid group. Any material can be used and is not particularly limited. By using the organic solvent in this way, the polymer film can easily swell and the sulfonating agent can be diffused into the film. Moreover, when a sulfonating agent and a polymer film contact directly, it can suppress that an excessive reaction arises and a film deteriorates. The amount of the sulfonating agent used is 0.1 to 100 times (weight ratio), more preferably 0.5 to 50 times (weight ratio) with respect to the polymer film. preferable. If it is in the said numerical range, the introduction amount of a sulfonic acid group will become a suitable range, and characteristics, such as proton conductivity of the obtained polymer electrolyte membrane, can fully be ensured. In addition, the polymer film can be prevented from being chemically deteriorated, and the mechanical strength of the resulting polymer electrolyte membrane can be prevented from being lowered. For this reason, handling is easy. In addition, sulfonic acid groups can be introduced in a suitable range, and deterioration of practical properties of the polymer electrolyte membrane, such as being soluble in water or methanol aqueous solution, can be prevented while maintaining methanol blocking properties.

  In addition, the concentration of the sulfonating agent in the organic solvent may be appropriately set in consideration of the target introduction amount of sulfonic acid groups and reaction conditions (temperature, time, etc.). Specifically, it is preferably 0.05% by weight or more and 20% by weight or less, and more preferably 0.2% by weight or more and 10% by weight or less. If it is in the range of 0.05% by weight or more and 20% by weight or less, the sulfonating agent and the aromatic unit in the polymer film can easily come into contact with each other, and a desired amount of sulfonic acid group can be introduced, and the introduction time is A short time is sufficient. Further, the introduction of sulfonic acid groups becomes uniform, and the mechanical properties of the obtained polymer electrolyte membrane can be sufficiently secured.

  In the present invention, considering the ease of introduction of sulfonic acid groups and the characteristics of the polymer electrolyte membrane obtained, the organic solvent is particularly preferably a halogenated hydrocarbon. Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, chloroform, 1-chloropropane, 1-chlorobutane, 2-chlorobutane, 1,4-dichlorobutane, 1-chloro-2-methylpropane, and 1-chloro. Examples include pentane, 1-chlorohexane, and chlorocyclohexane. In particular, the halogenated hydrocarbon is selected from the group consisting of dichloromethane, 1,2-dichloroethane, and 1-chlorobutane, taking into consideration industrial availability, ease of introduction of sulfonic acid groups, and characteristics of the obtained electrolyte membrane. It is preferable that the organic solvent contains at least one selected from the above. That is, in the present invention, the organic solvent preferably contains dichloromethane or 1-chlorobutane. These are easily available industrially, are easy to introduce a proton conductive group, and are compatible with proton conductivity and methanol blocking property of the obtained polymer electrolyte membrane.

  The reaction temperature for bringing the polymer film into contact with the sulfonating agent is not particularly limited, but is preferably 0 ° C. or higher and 100 ° C. or lower, more preferably 10 ° C. or higher and 30 ° C. or lower. If reaction temperature is 0 degreeC or more, measures, such as cooling on an installation, are unnecessary and it can prevent taking time more than necessary for reaction. Moreover, if it is 100 degrees C or less, reaction can be adjusted appropriately, generation | occurrence | production of a side reaction can be prevented and the problem of reducing the characteristic of a film | membrane can be avoided. Furthermore, it can be said that the reaction temperature when the polymer film and the sulfonating agent are brought into contact with each other is preferably equal to or lower than the boiling point of the organic solvent to be used because it is not necessary to use a pressure resistant container.

  The reaction time for bringing the polymer film into contact with the sulfonating agent is not particularly limited, but is preferably 0.5 hours or longer, and more preferably 2 hours or longer. On the other hand, the upper limit of the reaction time is preferably 100 hours or less. When the reaction time is 0.5 hour or longer, the contact between the sulfonating agent and the polymer in the polymer film is sufficient, and a desired amount of sulfonic acid groups can be introduced. Moreover, if the reaction time is 100 hours or less, the characteristics of the polymer electrolyte membrane can be improved without impairing the productivity. In practice, the reaction conditions for efficiently producing a polymer electrolyte membrane having desired characteristics should be appropriately set in consideration of the reaction atmosphere of the sulfonating agent and organic solvent used, the target production volume, etc. That's fine.

  In order to further improve the properties of the polymer electrolyte membrane produced by the production method of the present invention, it is possible to irradiate radiation such as electron beam, γ-ray, ion beam and the like. As a result, a crosslinked structure or the like can be introduced into the polymer electrolyte membrane, and the methanol barrier property may be further improved.

<3. Use of Polymer Electrolyte Membrane According to the Present Invention>
The polymer electrolyte membrane according to the present invention can be used in various industries, and the use (use) is not particularly limited. For example, a membrane using the above polymer electrolyte membrane- An electrode assembly can be mentioned. Such a membrane-electrode assembly can be used, for example, in a fuel cell, particularly a fuel cell such as a solid polymer fuel cell, a direct liquid fuel cell, and a direct methanol liquid fuel cell.

  That is, the present invention may include a fuel cell using the polymer electrolyte membrane.

  According to the membrane-electrode assembly and the fuel cell, since the polymer electrolyte membrane having both excellent proton conductivity and high methanol barrier property as described above is provided, it has high power generation characteristics and long-term durability.

  Next, an embodiment of a polymer electrolyte fuel cell using the polymer electrolyte membrane of the present invention will be described with reference to the drawings. In the present embodiment, a solid polymer fuel cell will be described as an example, but a direct liquid fuel cell and a direct methanol liquid fuel cell can also be implemented in the same manner as a solid polymer fuel cell. is there.

  FIG. 1 is a diagram schematically showing a cross-sectional structure of a main part of a polymer electrolyte fuel cell using a polymer electrolyte membrane according to the present embodiment. As shown in the figure, the polymer electrolyte fuel cell according to the present embodiment includes a polymer electrolyte membrane 1, a catalyst layer 2, a diffusion layer 3, and a separator 4.

  The polymer electrolyte membrane 1 is located substantially at the center of the cell of the polymer electrolyte fuel cell. The catalyst layer 2 is provided in contact with the polymer electrolyte membrane 1. The diffusion layer 3 is provided adjacent to the catalyst layer 2, and a separator 4 is disposed on the outer side thereof. The separator 4 is formed with a flow path 5 for feeding fuel gas or liquid (such as aqueous methanol solution) and an oxidant. In other words, these members are configured as cells of a polymer electrolyte fuel cell.

  Generally, a polymer electrolyte membrane 1 joined with a catalyst layer 2 or a polymer electrolyte membrane 1 joined with a catalyst layer 2 and a diffusion layer 3 is referred to as a membrane-electrode assembly (hereinafter referred to as “MEA”). It is used as a basic member of a polymer electrolyte fuel cell (direct liquid fuel cell, direct methanol liquid fuel cell).

  Methods for producing MEA are conventionally studied polymer electrolyte membranes made of perfluorocarbon sulfonic acid and other hydrocarbon polymer electrolyte membranes (for example, sulfonated polyetheretherketone, sulfonated polyethersulfone, sulfone). A known method performed with a sulfonated polysulfone, a sulfonated polyimide, a sulfonated polyphenylene sulfide, or the like is applicable.

  An example of a specific method for producing MEA is shown below, but the present invention is not limited to this.

  The catalyst layer 2 is formed by dispersing a metal-supported catalyst in a polymer electrolyte solution or dispersion to prepare a dispersion for forming the catalyst layer. The dispersion solution is applied onto a release film such as polytetrafluoroethylene by spraying, and the solvent in the dispersion solution is dried and removed to form a predetermined catalyst layer 2 on the release film. The catalyst layer 2 formed on the release film is disposed on both surfaces of the polymer electrolyte membrane 1, and hot-pressed under predetermined heating and pressurizing conditions to join the polymer electrolyte membrane 1 and the catalyst layer 2 and release them. The MEA in which the catalyst layers 2 are formed on both surfaces of the polymer electrolyte membrane 1 can be produced by peeling the mold film.

  Also, a catalyst-carrying gas diffusion electrode in which the dispersion solution is coated on the diffusion layer 3 using a coater or the like, the solvent in the dispersion solution is dried and removed, and the catalyst layer 2 is formed on the diffusion layer 3 Are arranged on both sides of the polymer electrolyte membrane 1, and the catalyst layer 2 side of the catalyst-carrying gas diffusion electrode is placed on both sides of the polymer electrolyte membrane 1 by hot pressing under predetermined heating and pressurizing conditions. An MEA in which the catalyst layer 2 and the diffusion layer 3 are formed can be manufactured. In addition, you may use a commercially available gas diffusion electrode (made by USA E-TEK company etc.) for the said catalyst carrying | support gas diffusion electrode.

  Examples of the polymer electrolyte solution include an alcohol solution of a perfluorocarbon sulfonic acid polymer compound (such as Nafion (registered trademark) solution manufactured by Aldrich) or a sulfonated aromatic polymer compound (eg, sulfonated polyether ether ketone). , Sulfonated polyethersulfone, sulfonated polysulfone, sulfonated polyimide, sulfonated polyphenylene sulfide, and the like) can be used. As the metal-supported catalyst, conductive particles having a high specific surface area can be used as a carrier, and examples thereof include carbon materials such as activated carbon, carbon black, ketjen black, vulcan, carbon nanohorn, fullerene, and carbon nanotube.

  Any metal catalyst may be used as long as it promotes the fuel oxidation reaction and oxygen reduction reaction, and the fuel electrode and the oxidant electrode may be the same or different. For example, noble metals such as platinum and ruthenium or alloys thereof can be exemplified, and a promoter for promoting their catalytic activity or suppressing poisoning by reaction by-products may be added.

  The dispersion solution for forming the catalyst layer may be appropriately diluted with water or an organic solvent so that the viscosity can be easily applied by spraying or coating with a coater. Moreover, you may mix fluorine-type compounds, such as polytetrafluoroethylene, in order to provide water repellency to the catalyst layer 2 as needed.

  As the diffusion layer 3, a porous conductive material such as carbon cloth or carbon paper can be used. In order to promote the diffusibility of the fuel and the oxidant and the discharge property of the reaction by-products and unreacted substances, it is preferable to use those coated with polytetrafluoroethylene or the like to impart water repellency. Further, an adhesive layer made of a polymer electrolyte as described above may be provided between the polymer electrolyte membrane 1 and the catalyst layer 2 as necessary.

  The conditions for hot-pressing the polymer electrolyte membrane 1 and the catalyst layer 2 under heating and pressurizing conditions need to be appropriately set according to the type of polymer electrolyte contained in the polymer electrolyte membrane 1 and the catalyst layer 2 to be used. There is. As the above-described conditions, the above-mentioned conditions are generally below the thermal degradation or thermal decomposition temperature of the polymer electrolyte contained in the polymer electrolyte membrane 1 or the catalyst layer 2, and the polymer electrolyte membrane 1 or the catalyst layer 2 It is preferable that the temperature is higher than the glass transition point and softening point of the polymer electrolyte contained, and further the temperature is higher than the glass transition point and softening point of the polymer electrolyte contained in the polymer electrolyte membrane 1 and the catalyst layer 2. .

  As the pressurizing condition, it is preferable that the pressure is in the range of about 0.1 MPa or more and 20 MPa or less because the polymer electrolyte membrane 1 and the catalyst layer 2 are in sufficient contact with each other and there is no deterioration in characteristics due to significant deformation of the material used. In particular, when the MEA is formed only from the polymer electrolyte membrane 1 and the catalyst layer 2, the diffusion layer 3 may be disposed outside the catalyst layer 2 and used only by contacting without being joined.

  The MEA obtained by the above method is inserted between a pair of separators 4 in which a flow path 5 for feeding fuel gas or liquid and an oxidant is formed, and the solid according to the present embodiment. A polymer fuel cell is obtained.

  As the separator 4, a conductive material such as carbon graphite or stainless steel can be used. In particular, when a metal material such as stainless steel is used, it is preferable to perform a corrosion resistance treatment.

  For the above polymer electrolyte fuel cell, as a fuel gas or liquid, a gas containing hydrogen as a main component or a gas or liquid containing methanol as a main component is used as a gas containing oxygen (oxygen or air) as an oxidant. ) Are supplied to the catalyst layer 2 from the separate flow paths 5 through the diffusion layer 3, respectively, so that the polymer electrolyte fuel cell generates electric power. At this time, for example, when a hydrogen-containing liquid is used as the fuel, a direct liquid fuel cell is obtained, and when methanol is used, a direct methanol liquid fuel cell is obtained. That is, it can be said that the above-described embodiment exemplified for the polymer electrolyte fuel cell can be applied to a direct liquid fuel cell and a direct methanol liquid fuel cell as they are.

  It should be noted that the polymer electrolyte fuel cells according to the present embodiment can be used alone or in a stacked manner to form a stack, or a fuel cell system incorporating them.

  Next, an embodiment of a direct methanol liquid fuel cell using the polymer electrolyte membrane of the present invention will be described with reference to the drawings.

  FIG. 2 is a diagram schematically showing a cross-sectional structure of a main part of a direct methanol liquid fuel cell comprising a polymer electrolyte membrane according to the present embodiment. As shown in the figure, the direct methanol liquid fuel cell according to the present embodiment includes an MEA 6, a fuel tank 7, and a support 9. The fuel tank 7 includes a fuel (methanol or methanol aqueous solution) filling section (supply section) 8, and an oxidant flow path 10 is formed in the support 9.

  The required number of MEAs 6 obtained by the above-described method is arranged in a planar shape on both sides of the fuel tank 7 having the fuel filling portion 8. Further, a support body 9 in which an oxidant flow path 10 is formed is disposed outside thereof. That is, a cell and stack of a direct methanol liquid fuel cell are formed by being sandwiched between the two supports 9.

In addition to the examples described above, the polymer electrolyte membrane according to the present invention is used as an electrolyte membrane of a solid polymer fuel cell or a direct methanol liquid fuel cell known in Patent Documents 6 to 16 and the like. Can be used. Based on these known documents, those skilled in the art can easily construct a solid polymer fuel cell or a direct methanol liquid fuel cell using the polymer electrolyte membrane of the present invention.
JP 2001-313046 A JP 2001-313047 A JP 2001-93551 A JP 2001-93558 A JP 2001-93561 A JP 2001-102069 A JP 2001-102070 A JP 2001-283888 A JP 2000-268835 A JP 2000-268836 A JP, 2001-283892, A An example is shown below and an embodiment of the invention is described in detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail. Further, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and the present invention is also applied to the embodiments obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples. Examples 1 and 4 are not examples of the present invention but reference examples.

(Example 1 ; reference example )
<Preparation of polymer electrolyte membrane>
Polyphenylene sulfide (manufactured by Dainippon Ink and Chemicals, LD10p11, melting point 285 ° C.) as the polymer electrolyte material, and high-density polyethylene (HI-ZEX 3300F, melting point 130 ° C.) as the polymer non-electrolyte material used. A pre-blended compound was prepared by dry blending 75 parts by weight of polyphenylene sulfide pellets and 25 parts by weight of high-density polyethylene pellets at a temperature of 290 degrees using a Berstorf twin screw extruder. A was produced. Next, only the polyphenylene sulfide pellets were melt-extruded with the pre-blended compound A prepared in advance using a Soken biaxial multilayer extruder set with a T die under the conditions of a screw temperature of 290 ° C. and a T die temperature of 290 ° C. A polyphenylene sulfide / pre-blend compound A two-type two-layer polymer film was obtained. In a glass container, 176.59 g of dichloromethane and 0.44 g of chlorosulfonic acid were weighed to prepare a 2.5 wt% chlorosulfonic acid solution. 0.41 g of the polymer film was weighed, immersed in the chlorosulfonic acid solution, and allowed to stand at 25 ° C. for 20 hours (the amount of chlorosulfonic acid added was 1.07 times the weight of the polymer film). . Thereafter, the polymer film was recovered and washed with ion exchange water until neutral. The polymer film after washing was dried in a constant temperature and humidity chamber adjusted to 23 ° C. for 30 minutes under humidity control of relative humidity 98%, 80%, 60% and 50%, An electrolyte membrane having a sulfonic acid group introduced therein was obtained.

<Measurement method of proton conductivity of electrolyte membrane>
A polymer electrolyte membrane (about 10 mm × 40 mm) stored in ion-exchanged water was taken out, and water on the surface of the polymer electrolyte membrane was wiped off with a filter paper. A polymer electrolyte membrane was placed in a dipolar non-sealed polytetrafluoroethylene cell, and a platinum electrode was placed 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 alternating current impedance method (frequency: 42 Hz to 5 MHz, applied voltage: 0.2 V, Hioki LCR meter 3531Z HITESTER), and proton conductivity was calculated. The results are shown in Table 1.

<Method for measuring methanol barrier property of electrolyte membrane>
In a 25 ° C. environment, ion exchange water and a 64% by weight aqueous methanol solution were isolated with a polymer electrolyte membrane using a membrane permeation experiment apparatus (KH-5PS) manufactured by Beadrex. After a predetermined time (2 hours), a solution containing methanol that had permeated to the ion-exchanged water was collected, and the amount of methanol permeated by a gas chromatograph (Shimadzu Gas Chromatography GC-201) 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. The results are shown in Table 1.
[Formula 1]
Methanol permeability coefficient (μmol / (cm · day))
= Methanol permeation amount (μmol) × film thickness (cm) / (membrane area (cm ² ) × permeation time (days))
<Observation of cross section of polymer electrolyte membrane>
An observation sample was prepared by processing the polymer electrolyte membrane of the present invention by an ultrathin section method. Using a JEOL transmission electron microscope (JEM-1200EX), the cross section in the thickness direction of the polymer electrolyte membrane was observed under the conditions of an acceleration voltage of 80 kV and a magnification of 2,000. The results are shown in FIG.

(Example 2)
<Preparation of polymer electrolyte membrane>
The same resin as in Example 1 was used. A blend of 25 parts by weight of polyphenylene sulfide pellets and 75 parts by weight of high density polyethylene pellets was dry-blended in advance using a Berstorf twin screw extruder at a temperature of 290 degrees, and a pre-blend compound. B was produced. Next, the pre-blended compound A and the pre-blended compound B prepared in advance were melt-extruded by a Soken biaxial multilayer extruder set with a T die under the conditions of a screw temperature of 290 ° C. and a T die temperature of 290 ° C., A pre-blend compound A / pre-blend compound B two-type two-layer polymer film was obtained. In a glass container, 136.59 g of dichloromethane and 1.37 g of chlorosulfonic acid were weighed to prepare a 9.9 wt% chlorosulfonic acid solution. 0.32 g of the polymer film was weighed, immersed in the chlorosulfonic acid solution, and allowed to stand at 25 ° C. for 20 hours (the amount of chlorosulfonic acid added was 4.3 times the weight of the polymer film). . Thereafter, the polymer film was recovered and washed with ion exchange water until neutral. The polymer film after washing was dried in a constant temperature and humidity chamber adjusted to 23 ° C. for 30 minutes under humidity control of relative humidity 98%, 80%, 60% and 50%, An electrolyte membrane having a sulfonic acid group introduced therein was obtained.

<Evaluation of polymer electrolyte membrane>
The polymer electrolyte membrane was evaluated in the same manner as in Example 1 (proton conductivity, methanol blocking property, cross-sectional observation). The results are shown in Table 1 and FIG.

(Example 3)
<Preparation of polymer electrolyte membrane>
The same resin as in Example 1 was used. A pre-blended compound is prepared by dry blending 50 parts by weight of polyphenylene sulfide pellets and 50 parts by weight of high-density polyethylene pellets at a temperature of 290 degrees using a Berstorf twin screw extruder. C was produced. Next, the pre-blended compound A and the pre-blended compound C prepared in advance were melt-extruded by a biaxial multilayer extruder manufactured by Soken with a T die set under the conditions of a screw temperature of 290 ° C. and a T die temperature of 290 ° C., A pre-blend compound A / pre-blend compound C two-type two-layer polymer film was obtained. In a glass container, 120.58 g of dichloromethane and 0.60 g of chlorosulfonic acid were weighed to prepare a 5.0 wt% chlorosulfonic acid solution. 0.28 g of the polymer film was weighed, immersed in the chlorosulfonic acid solution, and allowed to stand at 25 ° C. for 20 hours (the amount of chlorosulfonic acid added was 2.1 times the weight of the polymer film). . Thereafter, the polymer film was recovered and washed with ion exchange water until neutral. The polymer film after washing was dried in a constant temperature and humidity chamber adjusted to 23 ° C. for 30 minutes under humidity control of relative humidity 98%, 80%, 60% and 50%, An electrolyte membrane having a sulfonic acid group introduced therein was obtained.

<Evaluation of polymer electrolyte membrane>
The polymer electrolyte membrane was evaluated in the same manner as in Example 1 (proton conductivity, methanol blocking property, cross-sectional observation). The results are shown in Table 1 and FIG.

(Example 4 ; reference example )
<Preparation of polymer electrolyte membrane>
The same resin as in Example 1 was used. Pre-blended compound A and pre-blended compound C were melt-extruded using a Soken biaxial multi-layer extruder set with a T die under the conditions of a screw temperature of 290 ° C. and a T die temperature of 290 ° C. A two-layer three-layer polymer film of A / pre-blend compound C was obtained (pre-blend compound A is the surface layer). In a glass container, 97.83 g of dichloromethane and 1.96 g of chlorosulfonic acid were weighed to prepare a 2.0 wt% chlorosulfonic acid solution. 0.23 g of the polymer film was weighed, immersed in the chlorosulfonic acid solution, and allowed to stand at 25 ° C. for 20 hours (the amount of chlorosulfonic acid added was 8.5 times the weight of the polymer film). . Thereafter, the polymer film was recovered and washed with ion exchange water until neutral. The polymer film after washing was dried in a constant temperature and humidity chamber adjusted to 23 ° C. for 30 minutes under humidity control of relative humidity 98%, 80%, 60% and 50%, An electrolyte membrane having a sulfonic acid group introduced therein was obtained.

<Evaluation of polymer electrolyte membrane>
The polymer electrolyte membrane was evaluated in the same manner as in Example 1 (proton conductivity, methanol blocking property, cross-sectional observation). The results are shown in Table 1 and FIG.

(Comparative Example 1)
<Preparation of polymer electrolyte membrane>
A commercially available Nafion (registered trademark) 115 generally used as an electrolyte membrane for a polymer electrolyte fuel cell was prepared.

<Evaluation of polymer electrolyte membrane>
The polymer electrolyte membrane was evaluated in the same manner as in Example 1 (proton conductivity, methanol blocking property). The results are shown in Table 1.

(Comparative Example 2)
<Preparation of polymer electrolyte membrane>
Polyphenylene sulfide (Dainippon Ink Industries, Ltd., DIC-PPS LD10p11) was used. The polyphenylene sulfide pellets were melt-extruded with a twin screw extruder in which a T die was set in a twin screw extruder under the conditions of a screw temperature of 290 ° C. and a T die temperature of 290 ° C. to obtain a polymer film. The polymer film obtained by the above method was used. Except for weighing 10.9 g of 1-chlorobutane and 1.1 g of chlorosulfonic acid to prepare a 1.5 wt% chlorosulfonic acid solution and changing the polymer film to 0.16 g, the same procedure as in Example 1 was performed. A polymer electrolyte membrane was obtained (the amount of chlorosulfonic acid added was 6.9 times that of the polymer film).

<Evaluation of polymer electrolyte membrane>
The polymer electrolyte membrane was evaluated in the same manner as in Example 1 (proton conductivity, methanol blocking property). The results are shown in Table 1.

(Comparative Example 3)
<Preparation of polymer electrolyte membrane>
The same resin as in Example 1 was used. 50 parts by weight of polyphenylene sulfide pellets and 50 parts by weight of high density polyethylene pellets were dry blended. The dry blended pellet mixture was melt-extruded by a twin screw extruder with a T die set under the conditions of a screw temperature of 290 ° C. and a T die temperature of 290 ° C. to obtain a polymer film (high in the polymer film). 50% by weight density polyethylene). In a glass container, 823 g of dichloromethane and 8.2 g of chlorosulfonic acid were weighed to prepare a 1.0 wt% chlorosulfonic acid solution. 1.9 g of the polymer film was weighed, immersed in the chlorosulfonic acid solution, and allowed to stand at 25 ° C. for 20 hours (the amount of chlorosulfonic acid added was 4.3 times the weight of the polymer film). . Thereafter, the polymer film was recovered and washed with ion exchange water until neutral. The polymer film after washing was dried in a constant temperature and humidity chamber adjusted to 23 ° C. for 30 minutes under humidity control of relative humidity 98%, 80%, 60% and 50%, An electrolyte membrane having a sulfonic acid group introduced as a proton conductive group was obtained.

<Evaluation of polymer electrolyte membrane>
The polymer electrolyte membrane was evaluated in the same manner as in Example 1 (ion exchange capacity, proton conductivity, methanol blocking property). The results are shown in Table 1.

From Table 1, the polymer electrolyte membranes of Examples 1 to 4 have proton conductivity of the same order as that of the polymer electrolyte membrane described in Comparative Example 1 generally used in solid polymer fuel cells. It was found that it has excellent proton conductivity as an electrolyte membrane for molecular fuel cells.

  From Table 1, it was found that the polymer electrolyte membranes of Examples 1 to 4 had excellent methanol barrier properties as compared with Comparative Examples 1 and 2. Moreover, it was found from the comparison with Comparative Example 3 that the polymer electrolyte membrane of the example had a large proportion of the electrolyte on the surface layer on at least one side, and it was easy to form a proton conduction path when joined to the electrode. That is, the polymer electrolyte membrane according to the present invention can form a good proton transmission path with the electrode while having excellent proton conductivity and methanol blocking properties.

  3 to 6, in any of Examples 1 to 4, in the composite part of the polymer electrolyte and the polymer non-electrolyte, a structure in which the polymer electrolyte is dispersed in the polymer non-electrolyte in a granular form, or respectively It can be seen that has a layered structure and that the polymer electrolyte is in the form of 5 microns or less in the thickness direction of the membrane.

  The polymer electrolyte membrane according to the present invention has various industrial applicability including fuel cells such as solid polymer fuel cells, direct liquid fuel cells, and direct methanol fuel cells.

It is principal part sectional drawing of the polymer electrolyte fuel cell (direct methanol fuel cell) of this invention. It is principal part sectional drawing of the direct methanol type fuel cell of this invention. 2 is a transmission electron microscope image of a cross section of the polymer electrolyte membrane in Example 1. FIG. 3 is a transmission electron microscope image of a cross section of the polymer electrolyte membrane in Example 2. FIG. 4 is a transmission electron microscope image of a cross section of the polymer electrolyte membrane in Example 3. FIG. 6 is a transmission electron microscope image of a cross section of the polymer electrolyte membrane in Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polymer electrolyte membrane 2 Catalyst layer 3 Diffusion layer 4 Separator 5 Flow path 6 Membrane-electrode assembly (MEA)
7 Fuel tank 8 Fuel filling part 9 Support body 10 Oxidant flow path

Claims (11)

A composite electrolyte membrane comprising a polymer electrolyte and a polymer non-electrolyte, take the complex form of the following (A), Ri Do at least two layers with a blending ratio of different polyelectrolyte / polymer non-electrolyte , At least one layer having a structure in which a polymer electrolyte is dispersed in a granular form in a polymer non-electrolyte :
(A) When the cross section in the thickness direction of the electrolyte membrane is observed with a transmission electron microscope, the polymer electrolyte has a structure in which the polymer electrolyte is dispersed in a granular form in the polymer non-electrolyte, or each has a layered structure. , a contact and a polymer electrolyte is 5 microns or less in the form in the thickness direction of the film.   2. The polymer electrolyte membrane according to claim 1, comprising at least one layer made of only a polymer electrolyte. 3.   The polymer electrolyte membrane according to claim 1 or 2, having a structure composed of two layers. 2. The structure according to claim 1 , wherein the ratio of the polymer electrolyte to the polymer non-electrolyte in the surface layer is larger as a ratio of the polymer electrolyte than the other layers. 2. The polymer electrolyte membrane according to 2. The polymer electrolyte has a structure in which a sulfonic acid group is introduced into at least one polymer compound selected from the group consisting of the following (i) to (iii), or a mixture thereof: The polymer electrolyte membrane according to any one of claims 1 to 4, wherein:
(I) polystyrene, syndiotactic polystyrene, polyphenylene ether, modified polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, and polyphenylene sulfide;
(Ii) a copolymer comprising the polymer compound described in (i) above;
(Iii) A derivative of the polymer compound described in (i) and (ii) above. 6. The polymer electrolyte membrane according to claim 1, wherein the polymer non-electrolyte is a polymer compound having a repeating unit represented by the following general formula (1), or a mixture thereof. :
-(CX ₁ X ₂ -CX ₃ X ₄ )-(1)
(Wherein, X ₁ ~ ₄ is, H, based on any one of _{CH 3, Cl, F, OCOCH} 3, CN, COOH, are selected from the group consisting of COOCH _3, and OC ₄ H _9, X ₁ ~ ₄ are independent of each other and may be the same or different.   The polymer non-electrolyte is one polymer compound selected from the group consisting of polyethylene, polypropylene, polymethylpentene, and derivatives thereof, or a mixture thereof. 7. The polymer electrolyte membrane according to any one of 6.   A film comprising at least two layers containing a polymer compound having an aromatic unit and a polymer compound not having an aromatic unit is prepared, and the film is obtained by introducing a sulfonic acid group into the film. The manufacturing method of the polymer electrolyte membrane in any one of Claims 1-7. The polymer according to claim 8 , wherein a film comprising at least two layers containing a polymer compound having an aromatic unit and a polymer compound having no aromatic unit is produced by multilayer extrusion. Manufacturing method of electrolyte membrane.   A polymer electrolyte membrane according to any one of claims 1 to 7, or a polymer electrolyte membrane produced by the production method according to any one of claims 8 to 9. A membrane-electrode assembly.   The polymer electrolyte membrane according to any one of claims 1 to 7, the polymer electrolyte membrane produced by the production method according to any one of claims 8 to 9, or the membrane according to claim 10. -A fuel cell comprising an electrode assembly.