JP4984410B2 - Electrode catalyst layer for polymer electrolyte fuel cell and membrane electrode composite for polymer electrolyte fuel cell - Google Patents

Description

The present invention relates to an electrode catalyst layer for a polymer electrolyte fuel cell, an electrode for a polymer electrolyte fuel cell using the electrode catalyst layer, and a polymer electrolyte fuel cell using a liquid fuel.

A fuel cell is a power generation device with low emissions, high energy efficiency, and low environmental burden. For this reason, it is in the spotlight again in recent years to the protection of the global environment. Compared to conventional large-scale power generation facilities, this is a power generation device expected in the future as a relatively small-scale distributed power generation facility, and as a power generation device for mobile objects such as automobiles and ships. It is also attracting attention as a power source for small mobile devices and portable electronic devices, and is expected to be installed in mobile devices such as mobile phones and personal computers instead of secondary batteries such as nickel metal hydride batteries and lithium ion batteries. .

In the polymer electrolyte fuel cell, in addition to the conventional polymer electrolyte fuel cell using hydrogen gas as a fuel (hereinafter referred to as PEFC), a direct methanol fuel cell that directly supplies a methanol aqueous solution of liquid fuel ( (Hereinafter referred to as DMFC) is also attracting attention. DMF
Although C has a lower output than the conventional PEFC, the fuel is liquid and does not use a reformer, so the energy density is high and the use time of the portable device per filling is long. is there.

In a fuel cell, an anode electrode and a cathode electrode in which a reaction responsible for power generation occurs and an electrolyte membrane serving as an ion conductor between the anode and the cathode constitute a membrane-electrode complex (MEA), and this MEA is separated by a separator. The sandwiched cell is configured as a unit. Here, the electrode is an electrode substrate (also referred to as a gas diffusion electrode or a current collector) that supplies fuel liquid or gas, discharges a product, and collects (supply) electricity, and actually serves as an electrochemical reaction field. And an electrode catalyst layer.

For example, in an anode electrode of a polymer electrolyte fuel cell, a fuel such as a methanol aqueous solution reacts with a catalyst layer of the anode electrode to generate protons, electrons, and carbon dioxide, and electrons are transferred to the electrode substrate and protons are transferred to the polymer solid electrolyte. Carbon dioxide is discharged out of the system. For this reason, the anode electrode is required to have good liquid fuel penetration, gas diffusivity, electronic conductivity, and ionic conductivity, and to maintain these performances chemically and physically. Stability is required.

On the other hand, in the cathode electrode, an oxidizing gas such as oxygen or air reacts with protons conducted from the polymer solid electrolyte and electrons conducted from the electrode substrate in the catalyst layer of the cathode electrode to produce water. For this reason, in the cathode electrode, it is necessary to efficiently discharge the generated water in addition to gas diffusibility, electron conductivity, and ion conductivity. In particular, in DMFC, a reaction in which methanol and oxygen or oxygen such as air that permeate the electrolyte membrane generate carbon dioxide and water in the catalyst layer of the cathode electrode also occurs. For this reason, since the amount of generated water is larger than that of conventional PEFC, it is necessary to discharge water more efficiently.
Chemical and physical stability is required to maintain these performances.

In particular, in a DMFC using liquid fuel, the polymer contained in the electrode catalyst layer is required to have durability to maintain power generation performance without being eluted or swollen with respect to the liquid fuel. However, conventionally, in order to promote the electrode reaction, it is considered that the polymer of the electrode catalyst layer needs to have proton conductivity, and a polymer having an ionic group has been used. Since the polymer having an ionic group generally has a possibility of swelling or dissolving in a methanol aqueous solution that is a liquid fuel of DMFC, it has been a big problem for improving the durability of DMFC.

  An example of improving the methanol resistance of the electrode catalyst layer of DMFC is a membrane electrode assembly comprising an electrode catalyst layer characterized by comprising a three-dimensional cross-linked structure containing silane and carbon fine particles supporting a noble metal catalyst. It has been proposed (see Patent Document 1).

On the other hand, there are some examples in which a polymer containing no ionic group is used for the electrode catalyst layer binder, but all are used in a mixture with a polymer containing an ionic group. For example, a catalyst layer is proposed in which a mixture of a suspension in which a fluororesin not containing ionic groups is dispersed in a solvent and a polymer containing ionic groups is used as a binder (see Patent Document 2). As a polymer therein, a mixture of a solvent-soluble fluoropolymer substantially free of ion exchange groups and a solvent-soluble fluoropolymer having an ionic group has been proposed (see Patent Document 3).
JP 2003-178770 A JP 2003-109603 A JP 2001-357858 A

However, in Patent Document 1 in which a cross-linking component is included in the polymer of the electrode catalyst layer, the pot life of the catalyst coating solution is shortened and a problem remains in productivity. Further, in Patent Document 2 and Patent Document 3 and the like, a polymer having an ionic group is substantially used for the binder of the electrode catalyst layer, and the amount thereof is not reduced. It did not essentially improve the problem.

  As described above, none of the conventional techniques can solve the swelling resistance, solvent resistance and chemical stability of the electrode catalyst layer in the fuel cell using liquid fuel.

  Furthermore, in portable power sources, which is an expected use of DMFC, an improvement in energy density can be expected by increasing the methanol concentration of the fuel, but the conventional electrode catalyst layer has very low durability against high concentration methanol. Therefore, there was a problem that sufficient performance could not be expressed.

  In view of the background of such prior art, the present invention provides an electrode catalyst layer and a polymer electrolyte fuel cell electrode capable of maintaining high performance over a long period of time, and a polymer electrolyte fuel cell using a liquid fuel using the same. To do.

The present invention employs the following means in order to solve such problems. That is, as a first means, the electrode catalyst layer for a polymer electrolyte fuel cell of the present invention is an electrode catalyst layer for a polymer electrolyte fuel cell composed of a catalyst and a polymer. gender groups, not more than 1g per 0.3 mmol, the electrode catalyst layer is characterized in that polyphenylene sulfide sulfone and / or polyether ether ketone or Ranaru.

  Further, the polymer electrolyte fuel cell electrode, the polymer electrolyte fuel cell membrane electrode composite and the polymer electrolyte fuel cell membrane electrode composite of the present invention are all solid polymer fuel cell electrodes. The solid polymer fuel cell using the liquid fuel of the present invention is composed of such a membrane electrode assembly for a solid polymer fuel cell. It is a feature. The portable device or moving body of the present invention is characterized in that a solid polymer fuel cell using such a liquid fuel is used as a drive source.

  According to the present invention, it is possible to provide an excellent fuel cell that is superior in durability and high in performance and energy density as compared with the conventional one.

  The present invention is surprising if the above-mentioned problem, that is, an electrode catalyst layer for a polymer electrolyte fuel cell capable of maintaining high performance for a long period of time, is intensively studied and the anionic group in the electrode catalyst layer is substantially eliminated. , It has been clarified that such problems can be solved all at once.

  Conventionally, it has been considered that introduction of an ionic group in an electrode catalyst layer of a polymer electrolyte fuel cell leads to output. For this purpose, for example, polymers having ionic groups have been used for the electrode catalyst layer. However, the polymer has the disadvantage that it easily swells and that chemical reactions such as decomposition and desorption easily occur, and it has been difficult to improve durability. In particular, in a DMFC using a liquid fuel, it was impossible to overcome a decrease in durability due to swelling of methanol and the like. As a result of intensive studies, the inventors have found that, by substantially not containing an anionic group of the electrode catalyst layer, durability can be enhanced and sufficient output can be obtained. This is considered to be because the swelling resistance, solvent resistance, and chemical stability of the electrode catalyst layer were remarkably improved by containing substantially no anionic group.

  That is, as described in the background art, a polymer having no anionic group has been conventionally used as a polymer in an electrode catalyst layer for a polymer electrolyte fuel cell. The electrocatalyst layer is used in a system mixed with a polymer having an ionic group or an anionic group-containing compound, and the content of the ionic group is substantially large. It was. Therefore, none of the conventional electrocatalyst layers contains substantially no anionic group.

The present invention provides the electrode catalyst layer which does not substantially contain an anionic group in the entire electrode catalyst layer for a polymer electrolyte fuel cell. Specifically, the electrode catalyst layer for a polymer electrolyte fuel cell of the present invention (hereinafter simply referred to as an electrode catalyst layer) has an anionic group of 0.3 mmol per 1 g of the electrode catalyst layer. (Hereinafter, the case where the anionic group is 0.3 mmol or less per 1 g of the electrode catalyst layer may be referred to as “substantially does not contain an anionic group”). It is more preferable if it is 0.05 mmol or less, and still more preferable if it is 0.01 mmol or less.

Conventionally, such an electrocatalyst layer is composed of a catalyst and a polymer. However, in the case of an electrocatalyst layer that does not substantially contain an anionic group as in the present invention, the polymer is an anion. It is that it does not contain a sex group substantially. Here, as the specific polymers, polymer of organic is be used preferably.

As a specific example of the polymer having substantially no anionic group in the present invention, the catalyst particles are well dispersed, do not swell, deform or dissolve in the fuel, and deteriorate in the oxidation-reduction atmosphere in the fuel cell. Polymers that do not are preferred. Examples of such a polymer include heat-resistant and oxidation-resistant polymers such as polyphenylene sulfide sulfone (PPSS) and polyether ether ketone (PEEK ) .

The polymer having substantially no anionic group in the present invention preferably has an ion exchange capacity of 2.0 meq or less, more preferably 1.5 meq or less, and even more preferably 0.7 meq or less. 0.1 meq or less, more preferably 0.05 meq or less. Wherein the poly Ma inter alia in the hydrocarbon-based polymer from the viewpoint of durability and cost 2.0meq below, the following is preferably used 0.5meq is a fluorine-containing polymer. The ion exchange capacity can be measured in the same manner as in the anionic group content test described below.

It is preferred polymers conductive electrode catalyst layer is the degree of swelling when immersed for 24 hours in 60 ° C. of the liquid fuel from the viewpoint of durability is not more than 120%. Further, it is more preferably 110% or less, and most preferably 105% or less. Here, the degree of swelling means a value when the polymer film is dried at 100 ° C. for 30 minutes and then the dimension after dipping in a liquid fuel is divided by the dimension before dipping (the dimension after drying). For example, a polymer film having a length of 2 cm and a width of 1 cm is prepared, dried at 100 ° C. for 30 minutes, and the length is measured. After immersing this in 60 degreeC liquid fuel, the length is measured. The length after immersion is divided by the length before immersion and expressed as a percentage.

  The polymer having substantially no anionic group in the present invention preferably has a glass transition temperature of 150 ° C. or lower, more preferably 100 ° C. or lower, and even more preferably 50 ° C. or lower. This is considered to be because the lower the glass transition temperature, the easier the deformation and the better the adhesion at the interface. The glass transition temperature of the polymer can be measured using a differential scanning calorimeter (DSC).

  The polymer having substantially no anionic group in the present invention preferably has a water contact angle at 20 ° C. of 50 ° or more, more preferably 70 ° or more, and even more preferably 100 ° or more. This is because the smaller the water contact angle, the more the fuel sticking is suppressed and the higher the affinity with the catalyst. The contact angle of water can be measured as follows. First, a polymer is coated on a slide glass with a thickness of 1 μm or more. Or a polymer film is produced. Immerse any of the above samples in water for at least 1 hour. After removing the sample and removing the droplets on the surface, the contact angle of water is measured using a static contact angle meter at an ambient temperature of 20 ° C.

The polymer preferably having substantially no anionic group in the present invention preferably has a volume resistance of 10 ⁵ Ω · cm or more, more preferably 10 ⁸ Ω · cm or more, and more preferably 10 ¹² Ω · cm. The above is more preferable. This is considered to be because the larger the volume resistance, the more difficult it is to swell in fuel. The volume resistance of the polymer can be measured by the following method. A polymer film having a thickness of 50 to 100 μm is prepared and immersed in ion exchange water for 24 hours or more. The ion conductivity of this film was measured by the following method, and the reciprocal thereof was taken as the volume resistance.
(Ion conductivity measurement method)
Hokuto Denko's electrochemical measurement system HAG5010 (HZ-3000 50V 10A Power Unit, HZ-3000 Automatic Polarization System) and NF circuit design block frequency characteristic analyzer (Frequency Response Analyzer) 5010 are used at 25 ° C. The constant potential impedance was measured by the method, and the ionic conductivity was determined from the Nykist diagram. The AC amplitude was 500 mV. As the sample, a membrane having a width of about 10 mm and a length of about 10 to 30 mm was used. The sample used was immersed in water until immediately before the measurement. As electrodes, platinum wires (two wires) having a diameter of 100 μm were used. The electrodes were arranged on the front side and the back side of the sample film so as to be parallel to each other and perpendicular to the longitudinal direction of the sample film.

In the present invention, the polymer weight in the electrode catalyst layer is preferably 0.1 mg / cm ² or more and 5 mg / cm ² or less. When the polymer weight is less than 0.1 mg / cm ² , the binding force becomes poor, and the durability of the electrode catalyst layer decreases. Moreover, when it exceeds 5 mg / cm < ² >, the fuel in the electrode catalyst layer and the liquid and gas of a reactive organism may become difficult to move.

  Although the electrode catalyst of the electrode catalyst layer in the present invention is not particularly limited, noble metals or transition metals such as platinum, gold, palladium, ruthenium, iridium, cobalt, nickel, iron and titanium are preferably used because of proton generation reaction activity. It is done. Two or more elements such as alloys and mixtures of these metals may be contained. The electrode catalyst may be a metal-only particle or may be supported on carbon, and even if these are mixed, this is a preferred embodiment. When the electrode catalyst is a mixture of metal-only particles and supported carbon, the mixing ratio is not particularly limited. When the electrode catalyst is supported carbon, the carbon material is the same as the carbon used for the conductive agent listed below.

  As the conductive agent contained in the electrode catalyst layer in the present invention, various conductive agents can be used without particular limitation as long as they have excellent electronic conductivity and excellent durability within the electrode catalyst layer. For example, carbon, metal, metal compound, alloy, metalloid, organic conductive material and the like are preferably used.

  As a preferable conductive material contained in the electrode catalyst layer of the present invention, a carbon material is preferable from the viewpoint of a large specific surface area and corrosion resistance, and carbon black and nanocarbon materials are particularly preferably used.

  Specific examples of carbon black include channel black, thermal black, oil furnace black, acetylene black, and lamp black. Examples of oil furnace black include Vulcan (registered trademark) XC-72R and Vulcan (registered trademark) P manufactured by Cabot Corporation. , Black Pearls (registered trademark) 880, Black Pearls (registered trademark) 1100, Black Pearls (registered trademark) 1300, Black Pearls (registered trademark) 2000, Regal (registered trademark) 400, Ketjen Black (registered trademark) manufactured by Lion Corporation EC, Mitsubishi Chemical Corporation # 3150, # 3250, etc. are used, and Denka Black (registered trademark) manufactured by Denki Kagaku Kogyo Co., Ltd. is used as acetylene black. Among these, in particular, Vulcan (registered trademark) XC-72R manufactured by Cabot Corporation is particularly preferably used.

  As the nanocarbon material, carbon nanotubes, carbon nanohorns, fullerenes and the like are preferably used. It is also preferable to use a surface treated product or a mixture of these carbon materials. In addition to such carbon black, artificial graphite obtained from organic compounds such as natural graphite, pitch, coke, polyacrylonitrile, phenol resin, furan resin, carbon, gold, palladium, and the like can also be used. These conductive materials may be in the form of particles or fibers. Moreover, it is also possible to use a conductive material obtained by post-processing these carbon materials. The amount of these conductive materials added to the electrode catalyst layer is preferably 1 to 80%, more preferably 5 to 50% as a weight ratio.

The electrode catalyst weight of the electrode catalyst layer in the present invention is preferably 0.5 mg / cm ² or more and 7 mg / cm ² or less. Electrocatalyst weight can be analyzed by fluorescent X-ray analysis or ICP emission analysis.For example, after scraping the electrode catalyst layer from MEA and dissolving the polymer contained in the solvent, fluorescent X The amount of electrode catalyst can be determined by line analysis or the like. If the weight of the electrode catalyst is less than 0.5 mg / cm ² , the power generation performance is lowered, and if it exceeds 7 mg / cm ² , the electrode catalyst layer becomes too thick and the performance may be lowered or the cost may be increased.

  The mixing ratio of the electrode catalyst, the conductive material, and the polymer in the electrode catalyst layer of the present invention should be determined as appropriate according to the required electrode characteristics and is not particularly limited, but is the weight ratio of the conductive material and the polymer. 50/50 to 95/5 is preferable.

  The thickness of the electrode catalyst layer in the present invention is required to be a thickness that does not hinder the movement of a liquid such as a methanol aqueous solution or air fuel, or a liquid or gas of a reaction product such as carbon dioxide or water. Therefore, the thickness is preferably 150 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. On the other hand, if the thickness of the electrode catalyst layer is too thin, it is difficult to allow the catalyst to exist uniformly. The thickness of the electrode catalyst layer is about 100 to 1000 times with a scanning electron microscope (SEM) or transmission electron microscope (TEM), and more than 5 cross-sections are measured per 1 cm. The average value is used as a representative value at each observation point. The average value of the representative values is defined as the electrode catalyst layer thickness.

  The electrode catalyst layer of the present invention can be produced by a known method and is not particularly limited. Specific examples of the electrode catalyst layer forming method will be described below. The electrocatalyst coating liquid is kneaded with a three-roll, ultrasonic, homogenizer, wet jet mill, dry jet mill, mortar, stirring blade, satellite (rotation and revolution type) stirrer, or the like. The kneaded electrode catalyst coating solution is applied and dried by using a knife coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater flow coater or the like. The coating method is appropriately selected according to the viscosity and solid content of the coating solution. Moreover, the electrode catalyst layer coating liquid can be applied to either an electrode base material or an electrolyte membrane described later. Moreover, it is also possible to form a catalyst layer independently, and it peels, after apply | coating to a glass base material etc., drying. Furthermore, an anode catalyst layer produced separately may be transferred or sandwiched between an electrode substrate and a polymer solid electrolyte. As the transfer substrate in this case, a polytetrafluoroethylene (PTFE) sheet, or a glass plate or a metal plate whose surface is treated with a fluorine or silicone release agent is also used.

The electrode catalyst layer in the present invention does not substantially contain an anionic group, but this can be verified as follows. First, the following <Anionic group content test 1> can be used as a guide.
<Containment test 1 of anionic group>
(1) Preparation of test solution A test solution in which the electrode catalyst layer is dispersed in deionized water is prepared. At this time, when the electrode catalyst layer is integrated with the electrolyte membrane or the electrode substrate as a membrane electrode, it is physically peeled off. In addition, when a conductive layer that does not contain an electrode catalyst is formed between the electrode catalyst layer and the electrode substrate, the thickness of the electrode catalyst can be ascertained by conducting elemental analysis of this cross section. The electrode catalyst layer is separated by scraping or the like.
(2) Pretreatment of test solution The test solution prepared in (1) above is adjusted to a solid content concentration of 2 to 30% by weight, and sodium chloride is added so as to be 1N. Further, it is sufficiently dispersed using a homogenizer.
(3) Content test of anionic group A pH test paper is put into the test obtained in the above (2) to evaluate the pH. If the pH is 4 or more, it is judged that the anionic group is not substantially contained.

And content of an anionic group can be calculated | required quantitatively as follows.
<Anionic group content test 2> (1) Weighing of electrode catalyst layer The weight of the electrode catalyst layer is measured. At this time, when the electrode catalyst layer is integrated as a membrane electrode assembly, it is physically peeled off in the same manner as in <Anionic group content test 1> (1).
(2) Measurement of anionic group amount
(A) The weight-measured electrode catalyst layer is immersed in a 1N NaCl aqueous solution and stirred at 20 to 25 ° C. for 24 hours or more.

 (B) The liquid stirred for 24 hours or more in (A) is separated into solids by centrifugation or filtration, and the volume of the supernatant is measured.

 (C) Titrate the weighed solution with aqueous sodium hydroxide. The titration amount at this time is the amount (number of moles) of an anionic group contained in the immersed electrode catalyst layer. Divide the measured amount of anionic group (number of moles) by the amount of electrode catalyst layer (weight) soaked to obtain the number of moles of anionic group per weight of electrode catalyst.

 (D) In the above (B) and (C), the amount of 1N-NaCl aqueous solution and the normality of the sodium hydroxide solution are appropriately adjusted.

  In the anionic group content test 2, the amount of the anionic group contained in the electrode catalyst layer is 0.3 mmol or less per 1 g of the electrode catalyst layer, preferably 0.1 mmol or less, and 0.05 mmol or less. More preferably, it is more preferably 0.01 mmol or less, and even more preferably 1 μmmol or less.

The conductive electrode catalyst layer, after 30 minutes drying at 100 ° C. The electrode catalyst layer in terms of durability, residual amounts of catalyst in the electrode catalyst layer when immersed for 24 hours in 60 ° C. a liquid fuel (= weight after immersion / Weight after drying) is preferably 80% or more. It is more preferable if it is 90% or more, and still more preferable if it is 95% or more. The remaining amount of the catalyst is measured in the same manner as the above-mentioned electrode catalyst weight.

  It is also a preferred embodiment that the electrode catalyst layer of the present invention is a membrane electrode assembly (MEA) together with an electrode substrate and an electrolyte membrane.

  As an electrode base material in the membrane electrode assembly of the present invention, an electrode base material generally used for a fuel cell is used without particular limitation. For example, a porous conductive sheet having a conductive inorganic substance as a main component is used, and specific examples of the conductive inorganic substance include a fired body from polyacrylonitrile, a fired body from pitch, graphite, and expanded graphite. Carbon materials such as stainless steel, molybdenum and titanium are used. The form of the conductive inorganic material is not particularly limited, such as fibrous or particulate. Among them, Toray carbon paper TGP series, SO series, E-TEK carbon cloth, etc. are preferably used.

  The electrolyte membrane in the membrane electrode assembly of the present invention is not particularly limited as long as it is an electrolyte used in a normal fuel cell, but a solid polymer electrolyte membrane is preferably used as a proton conductive polymer material. . The proton conductive anionic group is not particularly limited, such as a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group.

  This solid polymer electrolyte membrane is composed of a hydrocarbon-based membrane having an anionic group such as a sulfonic acid group on a styrene-divinylbenzene copolymer or a heat-resistant engineering plastic, a fluoroalkyl ether side chain and a fluoroalkyl main chain. The copolymer is roughly divided into perfluoro-based copolymers, and should be appropriately selected according to the use and environment in which the fuel cell is used. A partial fluorine film partially substituted with fluorine atoms is also preferably used. Examples of perfluoro membranes include DuPont Nafion (registered trademark), Asahi Kasei Aspirex (registered trademark), Asahi Glass Flemion (registered trademark), etc., and partial fluorine membranes include polymers of trifluorostyrene sulfonic acid and polyfluorinated There are those in which a sulfonic acid group is introduced into vinylidene.

  As the solid polymer electrolyte membrane in the membrane electrode assembly of the present invention, an electrolyte membrane in which the amount of antifreeze water contained in the electrolyte membrane falls within a specific range is preferable. Here, the water present in the electrolyte membrane is composed of bulk water whose melting point is observed at 0 ° C. or higher, low melting water whose melting point is observed at less than 0 ° C., −30 ° C. or higher, and melting point at −30 ° C. or higher. The amount of electroosmotic water is defined by classifying the water into antifreeze water that is not observed and controlling the ratio of each water, especially the ratio of antifreeze water, to the range shown in the following formula.

(Antifreeze water rate) = [(Antifreeze water amount) / (Low melting point water amount + Antifreeze water amount)] × 100 (%)
The solid polymer electrolyte membrane is classified into a crosslinked type and a non-crosslinked type. In the crosslinked type, it is preferable that the amount of antifreeze water represented by the above-described formula is 20% by weight or more and 100% by weight or less. It is more preferably 30% by weight or more and 99.9% by weight or less, and particularly preferably 40% by weight or more and 99.9% by weight or less.

  In the non-crosslinked type, the amount of antifreeze water represented by the above formula is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 99.9% by weight, Further, it is particularly preferably 80% by weight or more and 99.9% by weight or less. Moreover, the above-mentioned amount of antifreeze water and the amount of low melting point water are values measured by the method described later.

Furthermore, it is preferable that the antifreeze water content represented by the following mathematical formula also falls within a specific range.
(Antifreeze water content) = [(Amount of antifreeze water in the solid polymer electrolyte membrane) / (Dry weight of the solid polymer electrolyte membrane)]] × 100 (%)
Also here, when the solid polymer electrolyte membrane is a crosslinked type, the antifreeze water content represented by the above formula is preferably 5% or more and 200% or less, and in the case of a non-crosslinked type, 20%. % Or more and 200% or less is preferable.

  The amount of antifreeze water and the content of antifreeze water in the solid polymer electrolyte membrane can be determined, for example, by the differential scanning calorimetry (DSC) method as described below.

  That is, after immersing the solid polymer electrolyte membrane in water at 20 ° C. for 12 hours, the solid polymer electrolyte membrane is taken out from the water, and excess surface adhering water is wiped off with gauze as quickly as possible, and then the weight (Gp) is measured in advance. After crimping in an alumina-coated aluminum sealed sample container, the total weight (Gw) of the sample and the sealed sample container is measured as quickly as possible, and DSC measurement is immediately performed. The measurement temperature program is to cool from room temperature to −30 ° C. at a rate of 10 ° C./min, and then increase the temperature to 5 ° C. at a rate of 0.3 ° C./min. The bulk water amount (Wf) is obtained using the following formula (n1), the low melting point water amount (Wfc) is obtained using the following formula (n2), and the value is subtracted from the total moisture content (Wt). The amount of antifreeze water (Wnf) is obtained [the following mathematical formula (n3)].

  Here, the bulk water amount (Wf), the low melting point water amount (Wfc), the antifreeze water amount (Wnf), and the total moisture content (Wt) are values expressed by the weight per unit weight of the dried sample. m is the dry sample weight, dq / dt is the DSC heat flux signal, T0 is the melting point of bulk water, and H0 is the melting enthalpy at the melting point of bulk water (T0).

  After the DSC measurement, a small hole is made in the sealed sample container, and after vacuum drying at 110 ° C. for 24 hours with a vacuum dryer, the total weight (Gd) of the sample and the sealed sample container is measured as quickly as possible. The dry sample weight (m) is determined by m = Gd−Gp, and the total moisture content (Wt) is determined by Wt = (Gw−Gd) / m 2.

  The equipment and conditions for DSC measurement are as follows.

DSC device: “DSC Q100” manufactured by TA Instruments
Data processor: "TRC-THADAP-DSC" manufactured by Toray Research Center
Measurement temperature range: -50 ° C to 5 ° C
Scanning speed: 0.3 ° C./min Sample amount: about 5 mg
Sample pan: Aluminum sealed sample container Temperature / calorie calibration: Melting point of water (0.0 ° C, heat of fusion 79.7 cal / g)
This measurement method was developed by Toray Research Center, Inc., and can be measured, for example, at Toray Research Center, Inc.

  The type of polymer used for the electrolyte membrane in the membrane electrode assembly of the present invention is not particularly limited as long as it satisfies the above-mentioned characteristics and requirements, but has an ionic group and is resistant to hydrolysis. A hydrocarbon-based polymer electrolyte membrane that excels in water resistance is preferable. Among these, specific examples of non-crosslinked hydrocarbon polymer electrolyte membranes include ionic group-containing polyphenylene oxide, ionic group-containing polyether ketone, ionic group-containing polyether ether ketone, and ionic group-containing polyether. Sulfone, ionic group-containing polyether ether sulfone, ionic group-containing polyether phosphine oxide, ionic group-containing polyether ether phosphine oxide, ionic group-containing polyphenylene sulfide, ionic group-containing polyamide, ionic group-containing polyimide, ion An aromatic hydrocarbon polymer having an ionic group such as an ionic group-containing polyetherimide, an ionic group-containing polyimidazole, an ionic group-containing polyoxazole, and an ionic group-containing polyphenylene. Here, the ionic group is not particularly limited as long as it is a negatively charged atomic group, but is preferably one having proton exchange ability. As such a functional group, a sulfonic acid group, a sulfuric acid group, a sulfonimide group, a phosphonic acid group, a phosphoric acid group, and a carboxylic acid group are preferably used.

  In addition, as the crosslinked hydrocarbon polymer electrolyte membrane, a crosslinked structure mainly composed of a vinyl monomer is preferably used. Specific examples of the vinyl monomer include acrylic monomers such as acrylonitrile, aromatic vinyl monomers such as styrene, N-phenylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, 2 , 2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 2H, 2H -A fluorine-containing monomer such as heptadecafluorodecyl (meth) acrylate is preferable. In addition, as monomers having a plurality of vinyl groups, aromatic polyfunctional monomers such as divinylbenzene, polyhydric alcohols such as ethylene glycol di (meth) acrylate, bisphenoxyethanol (meth) full orange acrylate, etc. Di-, tri-, tetra-, penta- and hexa- (meth) acrylates are particularly preferred. In particular, it is more preferable to copolymerize the vinyl monomer.

  The polymer constituting the polymer electrolyte membrane of the present invention preferably has a polymer molecular chain constrained, and the method is not particularly limited, and the polymer having proton conductivity and water / solvent resistance A restraining effect is expressed by mixing a plurality of types of polymers having excellent resistance. In particular, at the time of mixing, it is important that each polymer, specifically, a polymer having proton conductivity and a polymer having excellent water resistance and solvent resistance are compatible with each other. Further, the restraining effect can be obtained not only by mixing but also by a method such as crosslinking or internal penetrating polymer network.

  The electrolyte membrane in the membrane electrode assembly of the present invention is also preferably an electrolyte membrane obtained by adding an inorganic material to the above-described hydrocarbon-based polymer electrolyte membrane, or an electrolyte membrane made of only an inorganic material. Examples of these inorganic materials include metal oxides such as alumina, silica, zeolite, titania, zirconia, and ceria, and carbon materials such as fullerenol.

  In addition, the electrolyte membrane in the membrane electrode assembly of the present invention is preferably one having a membrane shape in which a proton conductive electrolyte is filled in a support. Examples of the support include a porous polymer film, a porous inorganic material, a woven fabric, and a nonwoven fabric.

  The thickness of the electrolyte membrane in the membrane electrode assembly of the present invention is not particularly limited, and is determined according to the physical properties of the electrolyte membrane such as proton conductivity and the performance of the membrane electrode assembly (MEA) in which it is used. It should be done. Specifically, 5 μm to 500 μm is preferably used from the viewpoint of the physical properties of the electrolyte membrane, the performance of the MEA, and the manufacturing method.

  It does not specifically limit as a manufacturing method of the membrane-electrode complex of this invention, A well-known method is applicable. When the electrode catalyst layer is formed on the electrode substrate, the electrode substrate with the electrode catalyst layer is bonded to an electrolyte such as a solid polymer electrolyte membrane. This bonding condition also depends on the characteristics of the fuel cell. Should be determined accordingly. In addition, when the electrode catalyst layer is formed on the electrolyte membrane, the electrolyte membrane with the electrode catalyst layer is joined to the electrode base material, and the joining conditions should be appropriately determined according to the characteristics of the fuel cell. Is.

  The electrode catalyst layer of the present invention and the membrane electrode assembly using the same can be suitably used for a polymer electrolyte fuel cell, particularly a direct methanol fuel cell of liquid fuel such as aqueous methanol solution.

  Such a fuel cell is not particularly limited, but a power supply source of a mobile body or a portable device is preferably used. In particular, portable devices such as mobile phones, notebook computers, PDAs, digital cameras, and video cameras are preferable, and automobiles such as passenger cars, buses, and trucks, ships, and railways are also preferable mobiles.

  Hereinafter, the details of the present invention will be further described according to each procedure using examples.

The evaluation method of what was produced in the Example below is demonstrated.
(Anionic group content test)
A test solution was prepared by dispersing the prepared anode electrode catalyst layer in deionized water. At this time, when the electrode catalyst layer was integrated with the electrolyte membrane or the electrode substrate as a membrane electrode, it was physically peeled off. In addition, when a conductive layer that does not contain an electrode catalyst is formed between the electrode catalyst layer and the electrode substrate, the thickness of the electrode catalyst can be ascertained by conducting elemental analysis of this cross section. The electrode catalyst layer was separated by scraping or the like. The weight of the separated electrode catalyst layer was measured. The electrocatalyst layer weighed was immersed in a 1N NaCl aqueous solution and stirred at 20 to 25 ° C. for 24 hours.

 The solid content was separated from the stirred liquid by centrifugation, and the volume of the supernatant was measured.

The weighed liquid was titrated with an aqueous sodium hydroxide solution. The titration amount at this time is the amount (number of moles) of an anionic group contained in the immersed electrode catalyst layer. The measured amount of anionic group (number of moles) was divided by the amount of electrode catalyst layer (weight) soaked to determine the number of moles of anionic group per weight of electrode catalyst.
(Amount of anionic group in polymer in electrode catalyst layer)
The produced anode electrode catalyst layer was separated in the same manner as described above. The separated electrocatalyst layer was put in a polar solvent such as N-methylpyrrolidone, the polymer was dissolved, and determined by nuclear magnetic resonance and elemental analysis.
(Swelling degree of polymer in electrode catalyst layer)
A film having a length of 2 cm and a width of 1 cm was produced from the polymer used for the electrode catalyst layer. This was dried at 100 ° C. for 30 minutes and the length was measured. This was immersed in a 30% aqueous methanol solution at 60 ° C. for 24 hours, and then its length was measured. The length after immersion was divided by the length before immersion to obtain the degree of swelling.
(Contact angle of polymer water in electrode catalyst layer)
The polymer used for the electrode catalyst layer was coated on a slide glass with a thickness of 1 μm or more. This sample was immersed in water for 1 hour. The sample was taken out, the surface droplets were removed by air blowing for 2 seconds, and the contact angle of water was measured in a room temperature-controlled at 20 ° C.
(Durability of electrode catalyst layer)
The electrode catalyst layer was dried at 100 ° C. for 30 minutes and weighed. It was immersed in a 30% methanol aqueous solution at 60 ° C. for 24 hours. The amount of platinum before and after immersion was measured by ICP emission analysis.
(MEA evaluation method)
This MEA was sandwiched between cells manufactured by Electrochem Co., Ltd., and a 30 wt% methanol aqueous solution was supplied to the anode side at 40 μl / cm 2 and air was supplied to the cathode side at 10 ml / cm 2. In the evaluation, a constant current was passed through the MEA, and the voltage at that time was measured. The measurement was performed until the current was increased successively until the voltage became 10 mV or less. The product of the current and voltage at each measurement point is the output.
(Electrode durability evaluation method)
The produced anode electrode was immersed in a 30% methanol aqueous solution at 60 ° C. overnight, and the state of the catalyst layer was visually confirmed.
(MEA durability evaluation method)
The prepared MEA was evaluated at 60 ° C. for 100 hours using a 30 wt% aqueous methanol solution, and then evaluated at 20 ° C. using a 30 wt% aqueous methanol solution in the same manner as the MEA evaluation method. The change in output before and after evaluation at 60 ° C. was compared.

[ Reference Example 1]
(1) Preparation and evaluation of electrolyte membrane
(A) Preparation of polymer electrolyte polymer N-methylpyrrolidone using 35 g of potassium carbonate, 11 g of hydroquinone, 35 g of 4,4 ′-(9H-fluorene-9-ylidene) bisphenol, and 44 g of 4,4′-difluorobenzophenone Polymerization was performed at 155 ° C. in (NMP). After washing with water, purification was performed by re-precipitation with a large amount of methanol to produce a polymer electrolyte polymer represented by the following chemical formula (hereinafter referred to as FL50PEEK). The obtained polymer had a weight average molecular weight of 130,000. Moreover, it was 200 degreeC when the glass transition temperature (Tg) of this polymer was measured.

  After dissolving 50 g of FL50PEEK in chloroform under a nitrogen atmosphere at room temperature, 12 mL of chlorosulfonic acid was slowly added dropwise with vigorous stirring and allowed to react for 5 minutes. The white precipitate was separated by filtration, pulverized, sufficiently washed with water, and then dried to obtain the desired sulfonated FL50PEEK. The resulting sulfonated FL50PEEK had a sulfonic acid group density of 2.0 mmol / g from elemental analysis. Further, the glass transition temperature (Tg) of this polymer was measured and found to be 250 ° C. or higher (decomposition started).

(B) Preparation and evaluation results of polymer electrolyte membrane After the polymer obtained in (A) was substituted with Na by immersing with saturated saline, the polymer was cast on a glass substrate from an N, N-dimethylacetamide solution, and 100 ° C. For 4 hours, and after removing the solvent, heat treatment was performed at 300 ° C. for 10 minutes. The proton was replaced by immersion in 1N hydrochloric acid, and washed thoroughly with water. The obtained film had a thickness of 130 μm and was a colorless and transparent flexible film. This membrane has a 30 wt% methanol permeation rate of 16 μmol / (min · cm ² ), an ionic conductivity of 5.4 S / cm ² , an antifreeze water content rate of 86%, an antifreeze water content rate of 48%, and an antifreeze water content. Was 72% of the total water content, and the ionic conductivity was slightly higher than that of the Nafion (registered trademark) 117 membrane (Example 2), the effect of suppressing fuel crossover was great, and the amount of antifreeze water was extremely high.
(2) Production and evaluation results of membrane electrode assembly (MEA)
(A) Preparation of anode electrode and anionic group content test results Toray carbon paper TGP-H-090 was subjected to a water repellent treatment using a 20% polytetrafluoroethylene (PTFE) suspension and then fired. Thus, an anode electrode substrate was prepared. On this electrode base material, an anode electrode catalyst coating solution composed of Pt—Ru-supported carbon, Pt—Ru particles, polyvinylidene fluoride and dimethylacetamide, manufactured by Johnson Matthey, was coated and dried to prepare an anode electrode. The thickness of the electrode catalyst layer of the obtained anode electrode was 40 μm, and the amount of Pt was 2.0 mg / cm ² . The amount of anionic group per 1 g of the electrode catalyst layer was 0.01 mmol or less. The contact angle of polyvinylidene fluoride with water was 120 degrees.
(B) Production of Cathode Electrode A dispersion of acetylene black and a polytetrafluoroethylene (PTFE) suspension was applied to a carbon cloth manufactured by E-TEK and baked to produce a cathode electrode substrate. On this electrode substrate, a cathode electrode catalyst coating solution made of Tanaka Kikinzoku Kogyo's Pt-supported carbon, Johnson Matthey's Pt particles, and DuPont's Nafion (registered trademark) solution is applied and dried to produce a cathode electrode. did. The thickness of the electrode catalyst layer of the obtained cathode electrode was 40 μm, and the amount of Pt was 2.5 mg / cm ² .
(C) Production and evaluation results of MEA The membrane electrolyte composite is obtained by holding and pressing the polymer electrolyte membrane of the step (1) between the anode electrode and the cathode electrode produced in the steps (A) and (B). A body (MEA) was prepared. The output of MEA using the polymer electrolyte membrane of Example 1 was 25 mW / cm ² .
(3) MEA durability evaluation results The anode electrode prepared in (2) (A) was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(MEA durability evaluation results)
As a result of evaluating the durability of the MEA produced in (2) and (C), there was no change in output.

[Comparative Example 1]
(1) Production of electrolyte membrane and evaluation results An electrolyte membrane was produced and evaluated in the same manner as in Example 1 (1).
(2) Production and evaluation results of membrane electrode assembly (MEA) An electrode and MEA were produced in the same manner as in Example 1 (2) except that the polymer of the anode electrode catalyst layer was a Nafion (registered trademark) solution manufactured by DuPont. And evaluated. The output of the obtained MEA was 25 mW / cm ² . The amount of anionic group per 1 g of the anode electrode catalyst layer was 0.5 mmol.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. The electrode catalyst layer was completely removed from the electrode base material, and the aqueous methanol solution was changed to black.
(4) MEA durability evaluation result As a result of evaluating the durability of the MEA produced in the above (2), the output was reduced to 50%.

[ Reference Example 2]
(1) Evaluation result of Nafion (registered trademark) 117 Ion conductivity and MCO were evaluated using a commercially available Nafion (registered trademark) 117 membrane (manufactured by DuPont (trade name)). The Nafion (registered trademark) 117 membrane is immersed in 5% hydrogen peroxide water at 100 ° C. for 30 minutes, followed by 30 minutes in 5% dilute sulfuric acid at 100 ° C., and then thoroughly washed with deionized water at 100 ° C. did. Film thickness is 210μm, methanol permeation is 60μmol / (min · cm ² ), ionic conductivity is 5.0S / cm ² , antifreeze water content rate is 49%, antifreeze water content is 18%, antifreeze water amount Was 44% of the total water content.
(2) Production and Evaluation Results of Membrane Electrode Assembly (MEA) Using a Nafion (registered trademark) 117 membrane as an electrolyte membrane, an electrode and MEA were produced by the method described in Reference Example 1 (2) and evaluated. . The output was 10 mW / cm ² , which was lower than that of Reference Example 1.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(4) MEA Durability Evaluation Result As a result of evaluating the durability of the MEA produced in (2), there was no decrease in output.

[ Reference Example 3]
(1) Preparation and evaluation results of electrolyte membrane
(A) Preparation of monomer composition In a beaker, 11 g of styrene, 10 g of N-cyclohexylmaleimide, 6 g of ethylene glycol dimethacrylate as a polyfunctional monomer, 7 g of propylene carbonate as a pore-opening agent, and a polymerization initiator In addition to 0.05 g of 2,2′-azobisisobutyronitrile, the mixture was stirred and dissolved uniformly using a magnetic kustler to obtain a monomer composition solution.
(B) Cast molding: Prepare a mold prepared by adjusting two glass plates with a thickness of 5 mm and a size of 30 cm × 30 cm with a gasket so that the distance between them is 0.2 mm, and the monomer composition (A) above between the glass plates The product solution was injected until the gasket was filled.

Next, after polymerizing between plates in a hot air dryer at 65 ° C. for 8 hours, a film-like polymer was taken out between the glass plates to obtain a polymer film having a thickness of 190 μm.
(C) Production of polymer electrolyte membrane by removal of pore-opening agent and introduction of ionic groups The obtained polymer membrane was immersed in 1,2-dichloroethane to which 5% by weight of chlorosulfonic acid was added for 30 minutes. Thereafter, 1,2-dichloroethane was washed with methanol, and further washed with water until the washing solution became neutral, to produce a polymer electrolyte membrane having a thickness of about 200 μm.
(D) Characteristic evaluation result About the obtained polymer electrolyte membrane, the characteristic evaluation was performed by the method as described in the reference example 1 (1) (B). The amount of antifreeze water in the membrane was 59%, the content of antifreeze water was 38%, the ionic conductivity was 4.8 S / cm ² , and the methanol permeation amount was 12 μmol / (min · cm ² ).
(2) Production and evaluation results of membrane electrode assembly (MEA)
(A) Preparation of anode electrode After carbon-repellent treatment using 20% polytetrafluoroethylene (PTFE) suspension on Toray carbon paper TGP-H-090, carbon consisting of acetylene black and PTFE suspension A layer coating solution was applied and baked to prepare an anode electrode substrate. On this electrode substrate, an anode electrode catalyst coating solution composed of Pt-Ru particles, polytetrafluoroethylene-perfluoroalkyl ether copolymer (PFA), and an aromatic organic solvent is applied and dried to form an anode electrode. Produced. The obtained anode electrode catalyst layer had a thickness of 10 μm and a Pt amount of 1.5 mg / cm ² . The amount of anionic group per 1 g of the anode electrode catalyst layer was 0.001 mmol or less.
(B) Production of Cathode Electrode A dispersion of acetylene black and a polytetrafluoroethylene (PTFE) suspension was applied to a carbon cloth manufactured by E-TEK and baked to produce a cathode electrode substrate. On this electrode base material, a cathode electrode catalyst coating solution comprising Pt-supported carbon manufactured by Johnson Matthey, Pt particles manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., and Nafion (registered trademark) solution manufactured by DuPont is applied and dried to produce a cathode electrode. did. The thickness of the electrode catalyst layer of the obtained cathode electrode was 50 μm, and the amount of Pt was 2.5 mg / cm ² .
(C) MEA Production and Evaluation Results MEA was produced and evaluated in the same manner as in Example 1 (2) (C). The MEA output was 25 mW / cm ² .
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(4) MEA Durability Evaluation Result As a result of evaluating the durability of the MEA produced in (2), there was no decrease in output.

[ Reference Example 4]
(1) Preparation and evaluation results of electrolyte membrane
(A) Preparation of polymer electrolyte membrane Sulfonated polyphenylene sulfide sulfone (sulfonic acid group density: 2.3 mmol / g) was dissolved in N, N-dimethylformamide (DMF), and a yellow transparent solution (M -A1). A 0.01N hydrochloric acid aqueous solution was added to 6 g of tetrabutoxy titanium manufactured by Toray Dow Corning Silicone Co., Ltd., and stirred at room temperature for 30 minutes to obtain a colorless and transparent hydrolyzate (M-B1). 10 g of (M-A1) was collected, and 0.5 g of (M-B1) was added. This solution was impregnated into a polyimide base material having an independent through-hole with a porosity of 20% and a pore diameter of 12 μm, and heated at 100 ° C. for 40 minutes to produce a polymer electrolyte membrane. The film thickness was 20 μm.
(B) Evaluation Results of Polymer Electrolyte Membrane The polymer electrolyte membrane prepared in (A) has an antifreeze water content rate of 42%, an antifreeze water content rate of 43%, a proton conductivity of 5.8 S / cm ² , The methanol permeation amount was 16 μmol / (min · cm ² ).
(2) Manufacture and evaluation results of membrane electrode assembly (MEA) MEA was manufactured and evaluated in the same manner as in Example 1 (2). The output of the obtained MEA was 23 mW / cm ² . The amount of anionic group per 1 g of the anode electrode catalyst layer was 0.01 mmol.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(4) MEA Durability Evaluation Result As a result of evaluating the durability of the MEA produced in (2), there was no decrease in output.

[Example 1 ]
(1) Production and evaluation results of electrolyte membrane
An electrolyte membrane was prepared and evaluated in the same manner as in Reference Example 1 (1).
(2) Production and evaluation results of membrane electrode assembly (MEA) Similar to Reference Example 1 (2), except that the polymer of the anode electrode catalyst layer was replaced with sulfonated FL50PEEK containing 2.0 meq of sulfonic acid groups. Electrodes and MEAs were prepared and evaluated. Details of the evaluation results are shown in Table 1.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. Although the electrode catalyst layer was hardly dropped, it was slightly colored.
(4) Durability evaluation result of MEA Table 1 shows the result of evaluating the durability of the MEA produced in (2).

[Example 2 ]
(1) Production and evaluation results of electrolyte membrane
An electrolyte membrane was prepared and evaluated in the same manner as in Reference Example 1 (1).
(2) Production and evaluation results of membrane electrode assembly (MEA) Electrode as in Example 1 (2) except that the polymer of the anode electrode catalyst layer was replaced with sulfonated FL50PEEK containing 30% sulfonic acid group And MEA was produced and evaluated. Details of the evaluation results are shown in Table 1.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(4) Durability evaluation result of MEA Table 1 shows the result of evaluating the durability of the MEA produced in (2).

[Example 3 ]
(1) Preparation and evaluation results of electrolyte membrane
An electrolyte membrane was prepared and evaluated in the same manner as in Reference Example 1 (1).
(2) Preparation and evaluation results of membrane electrode assembly (MEA) Reference Example, except that the polymer of the anode electrode catalyst layer was replaced with sulfonated polyphenylene sulfide sulfone (sulfonated PPSS) containing 1.0 meq sulfonic acid group Electrodes and MEAs were prepared and evaluated in the same manner as 1 (2). Details of the evaluation results are shown in Table 1.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(4) Durability evaluation result of MEA Table 1 shows the result of evaluating the durability of the MEA produced in (2).

[Example 4 ]
(1) Production and evaluation results of electrolyte membrane
An electrolyte membrane was prepared and evaluated in the same manner as in Reference Example 1 (1).
(2) Production and evaluation results of membrane electrode assembly (MEA) An electrode and MEA were produced and evaluated in the same manner as in Reference Example 1 (2) except that the polymer of the anode electrode catalyst layer was replaced with FL50PEEK. Details of the evaluation results are shown in Table 1.
(3) MEA durability evaluation result The anode electrode prepared in (2) above was dried at 100 ° C for 30 minutes and then immersed in a 30% methanol aqueous solution at 60 ° C overnight. There was no loss of the electrode catalyst layer.
(4) Durability evaluation result of MEA Table 1 shows the result of evaluating the durability of the MEA produced in (2).

Claims (12)

In an electrode catalyst layer for a polymer electrolyte fuel cell using a liquid fuel composed of at least a catalyst and a polymer, the anionic group in the electrode catalyst layer is 0.3 mmol or less per gram, and the electrode catalyst layer is polyphenylene sulfide sulfone and / or polyether ether ketone or a solid polymer fuel cell electrode catalyst layer, characterized in that Ranaru. 2. The electrode catalyst layer for a polymer electrolyte fuel cell according to claim 1, wherein the anionic group in the electrode catalyst layer is 0.1 mmol or less per 1 g of the electrode catalyst layer. 3. The polymer electrolyte fuel cell electrode catalyst layer according to claim 1, wherein the polymer is composed of a polymer having no anionic group. The electrode catalyst layer for a polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the polymer has a glass transition temperature of 150 ° C or lower. 5. The electrode catalyst layer for a polymer electrolyte fuel cell according to claim 1, wherein the polymer has a water contact angle of 50 ° or more at 20 ° C. 5. In an electrode catalyst layer for a polymer electrolyte fuel cell using a liquid fuel composed of at least a catalyst and a polymer, the swelling degree when the polymer is immersed in a liquid fuel at 60 ° C. for 24 hours is 120% or less. The electrode catalyst layer for a polymer electrolyte fuel cell according to any one of claims 1 to 5. In an electrode catalyst layer for a polymer electrolyte fuel cell using a liquid fuel composed of at least a catalyst and a polymer, the amount of catalyst remaining in the electrode catalyst layer when the electrode catalyst layer is immersed in a liquid fuel at 60 ° C. for 24 hours The electrode catalyst layer for a polymer electrolyte fuel cell according to any one of claims 1 to 5, wherein is 80% or more. An anode electrode for a polymer electrolyte fuel cell, comprising the polymer electrolyte electrode catalyst layer according to any one of claims 1 to 7. A solid polymer comprising at least one of the polymer electrolyte electrode catalyst layer according to any one of claims 1 to 7 and the anode electrode for a polymer electrolyte fuel cell according to claim 8. Polymer membrane fuel cell membrane electrode composite. The membrane electrode assembly for a polymer electrolyte fuel cell according to claim 9, comprising a hydrocarbon-based polymer solid electrolyte membrane. A polymer electrolyte fuel cell using a liquid fuel, comprising the membrane electrode assembly for a polymer electrolyte fuel cell according to claim 10. A portable device or a moving body, characterized in that the solid polymer fuel cell using the liquid fuel according to claim 11 is used as a driving source.