JP7037696B1 - Manufacturing method of electrolyte membrane for direct methanol fuel cell and direct methanol fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrolyte membrane for a direct methanol fuel cell capable of suppressing a decrease in output and a direct methanol fuel cell system. A method for manufacturing an electrolyte membrane 33 includes a film forming step and an adsorption step. In the film forming step, an electrolyte film containing a ceramic material having ionic conductivity and an organic polymer material having insulating properties is formed. In the adsorption step, at least one of methanol and ethanol is adsorbed on the hydrophilic group contained in the electrolyte membrane. [Selection diagram] Fig. 1

Description

The present invention relates to a method for manufacturing an electrolyte membrane for a direct methanol fuel cell and a direct methanol fuel cell system.

Conventionally, as a kind of fuel cell, a direct methanol fuel cell (DMFC) using methanol as a fuel is known.

Conventionally, a solid polymer electrolyte composed of Nafion (DuPont, registered trademark), which is a perfluorosulfonic acid-based polymer, has been widely used as an electrolyte for a DMFC. There is a problem that the dimensional change is large in.

Therefore, Patent Document 1 proposes an electrolyte membrane in which a hydrocarbon-based polyelectrolyte and a support made of polytetrafluoroethylene are composited. However, Patent Document 1 has a problem that the durability is low because a polymer electrolyte is used.

Therefore, Patent Document 2 proposes an electrolyte membrane in which a ceramic material having ionic conductivity and a support made of an insulating material are composited.

Japanese Unexamined Patent Publication No. 2010-232158 International Publication No. 2019/12431

However, the electrolyte membrane described in Patent Document 2 has a problem that the output of the DMFC tends to decrease. As a result of diligent studies by the present inventors, one factor of the decrease in output is a hydrophilic group contained in the electrolyte membrane (for example, a hydroxyl group (-OH) or a carboxy group (-COOH) existing on the surface of a ceramic material or the like). It was found that the methanol supplied as a fuel permeates the electrolyte membrane through the adsorbed water ( _H2O ).

The present invention has been made based on the above-mentioned novel findings, and an object of the present invention is to provide a method for manufacturing an electrolyte membrane for a direct methanol fuel cell and a direct methanol fuel cell system capable of suppressing a decrease in output. do.

The method for producing an electrolyte membrane for a direct methanol fuel cell according to the present invention includes a film forming step of forming an electrolyte membrane containing a ceramic material having ionic conductivity and an organic polymer material having insulating properties, and an electrolyte membrane. It is provided with an adsorption step of adsorbing at least one of methanol and ethanol to the hydrophilic group contained in the above.

According to the present invention, it is possible to provide a method for manufacturing an electrolyte membrane for a direct methanol fuel cell and a direct methanol fuel cell system capable of suppressing a decrease in output.

Schematic diagram showing an example of the configuration of the DMFC system according to the embodiment.

(Configuration of direct methanol fuel cell system 1)
FIG. 1 is a schematic diagram showing a configuration of a direct methanol fuel cell system (hereinafter, abbreviated as “DMFC system”) 1.

The DMFC system 1 includes a housing 2 and a direct methanol fuel cell (hereinafter, abbreviated as "DMFC") 3.

(Housing 2)
The housing 2 houses the DMFC 3 inside.

The housing 2 has an oxidant supply unit 21 and a fuel supply unit 22 inside. The DMFC 3 is arranged between the oxidant supply unit 21 and the fuel supply unit 22.

The oxidant supply unit 21 supplies an oxidant containing oxygen (O ₂ ) to the cathode 31, which will be described later. As the oxidizing agent, it is preferable to use air, and it is more preferable that the air is humidified. The oxidant supply unit 21 has a supply pipe 21a, a supply space 21b, and a discharge pipe 21c. The oxidant introduced from the supply pipe 21a is supplied to the cathode 31 in the supply space 21b. The oxidant that is not consumed in the cathode 31 is discharged to the outside from the discharge pipe 21c.

During the operation of DMFC 3, the fuel supply unit 22 supplies fuel containing methanol (CH ₃ OH) to the anode 32, which will be described later, in a gas phase. Although only a part of methanol as a fuel may be in a vapor phase state, it is preferable that all of it is in a vapor phase state. The fuel supply unit 22 has a supply pipe 22a, a supply space 22b, and a discharge pipe 22c. The fuel introduced from the supply pipe 22a is supplied to the anode 32 in the supply space 22b. The fuel not consumed in the anode 32 and the carbon dioxide and water ( _H2O ) generated in the anode 32 are discharged to the outside from the discharge pipe 22c.

(DMFC3)
The DMFC3 is an example of a direct methanol fuel cell. DMFC3 is a kind of alkaline fuel cell (AFC: Alkaline Fuel Cell) having a hydroxide ion as a carrier. The DMFC 3 includes a cathode 31, an anode 32, and an electrolyte membrane 33 (an example of a direct methanol fuel cell electrolyte membrane).

DMFC3 preferably generates electricity at a relatively low temperature (for example, 50 ° C. to 250 ° C.) based on the following electrochemical reaction formula.

・ Cathode 31: 3 / 2O ₂ + 3H ₂ O + 6e ^－ → 6OH ^－
・ Anode 32: CH ₃ OH + ^6OH- → ^6e- + CO ₂ + 5H ₂ O
・ Overall: CH ₃ OH + 3 / 2O ₂ → CO ₂ + 2H ₂ O
1. 1. Cathode 31
The cathode 31 is an anode generally called an air electrode. During the power generation of the DMFC 3, an oxidizing agent containing oxygen (O ₂ ) is supplied to the cathode 31 from the oxidizing agent supply unit 21. The cathode 31 is a porous body capable of diffusing an oxidizing agent inside. The porosity of the cathode 31 is not particularly limited. The thickness of the cathode 31 is not particularly limited, but may be, for example, 10 to 200 μm.

The cathode 31 is not particularly limited as long as it contains a known air electrode catalyst used in an alkaline fuel cell. As an example of the catalyst of the cathode 31, in the periodic table of group 8 to 10 elements (IUPAC format) such as platinum group elements (Ru, Rh, Pd, Ir, Pt) and iron group elements (Fe, Co, Ni). Group 11 elements (elements belonging to groups 8 to 10), group 11 elements such as Cu, Ag, and Au (elements belonging to group 11 in the periodic table in the IUPAC format), rhodium phthalocyanine, tetraphenylporphyrin, Co-salen, Ni-salen (elements belonging to group 11), Cu, Ag, Au, etc. Salen = N, N'-bis (salicylidene) ethylenediamine), silver nitrate, and any combination thereof. The amount of the catalyst supported on the cathode 31 is not particularly limited, but is preferably 0.05 to 10 mg / cm ² , more preferably 0.05 to 5 mg / cm ² . The catalyst is preferably supported on carbon. Preferred examples of the cathode 31 are platinum-supported carbon (Pt / C), platinum-cobalt-supported carbon (PtCo / C), palladium-supported carbon (Pd / C), rhodium-supported carbon (Rh / C), and nickel-supported carbon (Ni). / C), copper-supported carbon (Cu / C), and silver-supported carbon (Ag / C).

The method for producing the cathode 31 is not particularly limited, but for example, an air electrode catalyst and, if desired, a carrier are mixed with a binder to form a paste, and the paste-like mixture is applied to one surface of the electrolyte membrane 33 to form the cathode 31. Can be done.

2. 2. Anode 32
The anode 32 is a cathode generally called a fuel electrode. During the power generation of the DMFC 3, fuel containing methanol is supplied to the anode 32 from the fuel supply unit 22. The anode 32 is a porous body capable of diffusing methanol inside. The porosity of the anode 32 is not particularly limited. The thickness of the anode 32 is not particularly limited, but may be, for example, 10 to 500 μm.

The anode 32 may include a known anode catalyst used in an alkaline fuel cell, and is not particularly limited. Examples of catalysts for the anode 32 include metal catalysts such as Pt, Ni, Co, Fe, Ru, Sn, and Pd. The metal catalyst is preferably supported on a carrier such as carbon, but may be in the form of an organic metal complex having a metal atom of the metal catalyst as a central metal, or the organic metal complex may be supported as a carrier. Further, a diffusion layer made of a porous material or the like may be arranged on the surface of the catalyst. Preferred examples of the anode 32 are nickel, cobalt, silver, platinum-supported carbon (Pt / C), platinum-luthenium-supported carbon (PtRu / C), palladium-supported carbon (Pd / C), and rhodium-supported carbon (Rh / C). , Nickel-supported carbon (Ni / C), copper-supported carbon (Cu / C), and silver-supported carbon (Ag / C).

The method for producing the anode 32 is not particularly limited, and for example, the anode catalyst and, if desired, a carrier may be mixed with a binder to form a paste, and the paste-like mixture may be applied to the other surface of the electrolyte membrane 33 to form the anode 32. can.

3. 3. Electrolyte membrane 33
The electrolyte membrane 33 is arranged between the cathode 31 and the anode 32. The electrolyte membrane 33 is formed in the form of a film, a layer, or a sheet. The thickness of the electrolyte membrane 33 is not particularly limited, but can be, for example, 5 to 100 μm.

The electrolyte membrane 33 includes a ceramic material having hydroxide ion conductivity and an organic polymer material having insulating properties. The content of the ceramic material in the electrolyte membrane 33 can be 30 to 70 vol%, preferably 50 to 70 vol% in consideration of ionic conductivity. The electrolyte membrane 33 may contain an additive (dispersant or the like), if desired.

The electrolyte membrane 33 contains a hydrophilic group. The hydrophilic group is a hydrophilic functional group such as a hydroxyl group (—OH) or a carboxy group (—COOH) existing on the surface of a ceramic material, an organic polymer material, or an additive.

In the present embodiment, at least one of methanol and ethanol (hereinafter collectively referred to as "methanol and the like") is adsorbed on at least a part of the hydrophilic groups contained in the electrolyte membrane 33.

As described above, since methanol or the like is previously adsorbed on the hydrophilic group contained in the electrolyte membrane 33, the water (H ₂ O) generated in the anode 32 is adsorbed on the hydrophilic group after the operation of DMFC 3 is started. Can be suppressed. Therefore, it is possible to prevent the methanol contained in the fuel from permeating through the electrolyte membrane 33 via the water adsorbed on the hydrophilic group. As a result, it is possible to suppress a decrease in the output of DMFC3. The method of adsorbing methanol or the like to a hydrophilic group in advance will be described later.

The ceramic material is dispersed in the organic polymer material. Ceramic materials are supported by organic polymer materials.

As the ceramic material, a well-known ceramic material having hydroxide ion conductivity can be used. Examples of such a ceramic material include layered double hydroxides (LDH) described below.

LDH is M ²⁺ _1-x M ³⁺ _x (OH) ₂ A ^n- x / n · mH ₂ O (in the formula, M ²⁺ is a divalent cation, M ³⁺ is a trivalent cation, and A ^n- is an n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, and m is an arbitrary integer meaning the number of moles of water). Have. Examples of M ²⁺ include Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , and Zn ²⁺ , and examples of M ³⁺ include Al ³⁺ , Fe ³⁺ , Ti ³⁺ , Examples include Y ³⁺ , Ce ³⁺ , Mo ³⁺ , and Cr ³⁺ , and examples of An ⁻ include CO ₃ ^2- and OH ⁻ . As M ²⁺ and M ³⁺ , one type may be used alone or two or more types may be used in combination.

LDH is composed of a plurality of hydroxide basic layers and an intermediate layer interposed between the plurality of hydroxide basic layers. The middle layer is composed of anions and _H2O . The hydroxide basic layer contains, for example, Ni, Al, Ti and OH groups when the metal M is Ni, Al, Ti. Hereinafter, the case where the hydroxide basic layer of LDH contains Ni, Al, Ti and OH groups will be described.

Ni in LDH can take the form of nickel ions. Nickel ions in LDH are typically considered to be Ni ²⁺ , but are not particularly limited as other valences such as Ni ³⁺ are possible. Al in LDH can take the form of aluminum ions. Aluminum ions in LDH are typically considered to be Al ³⁺ , but are not particularly limited as other valences are possible. Ti in LDH can take the form of titanium ions. Titanium ions in LDH are typically considered to be Ti ⁴⁺ , but are not particularly limited as other valences such as Ti ³⁺ are possible. The hydroxide basic layer preferably contains Ni, Al, Ti and OH groups as main components, but may contain other elements or ions, or may contain unavoidable impurities. The unavoidable impurity is an arbitrary element that can be unavoidably mixed in the production method, and can be mixed in LDH, for example, derived from a raw material or a base material.

The middle layer of LDH is composed of anions and _H2O . The anion is a monovalent or higher anion, preferably a monovalent or divalent ion. Preferably, the anions in ^LDH contain OH ^- and / or CO _3-2- .

As mentioned above, since the valences of Ni, Al and Ti are not always fixed, it is impractical or impossible to specify LDH strictly by a general formula. Assuming that the basic hydroxide layer is mainly composed of Ni ²⁺ , Al ³⁺ , Ti ⁴⁺ and OH groups, LDH is expressed by the general formula: Ni ²⁺ _1-xy Al ³⁺ _x Ti ⁴⁺ _y (OH). ) 2A ^n- _{(x + 2y) / n} · mH ₂ O ( _In the formula, Ann- is an n-valent anion, ⁿ is an integer of 1 or more, preferably 1 or 2, and 0 <x <1, preferably. 0.01 ≦ x ≦ 0.5, 0 <y <1, preferably 0.01 ≦ y ≦ 0.5, 0 <x + y <1, m is 0 or more, typically more than 0 or 1 or more It can be expressed by the basic composition (which is a real number of). However, the above general formula should be understood as "basic composition" to the extent that elements such as Ni ²⁺ , Al ³⁺ , and Ti ⁴⁺ do not impair the basic characteristics of LDH, and other elements or ions (of the same element). It should be understood as replaceable with elements or ions of other valences or elements or ions that can be unavoidably mixed in the process.

Organic polymer materials have insulating properties. As the organic polymer material, a well-known organic polymer material having an insulating property can be used. Examples of such organic polymer materials include polystyrene, polyether sulfone, polypropylene, epoxy resin, polyphenylene sulfide, fluororesin (tetrafluororesin: PTFE, etc.), cellulose, nylon, polyethylene, polyimide, polyvinylidene fluoride. And any combination thereof.

(Manufacturing method of electrolyte membrane 33)
Next, a method for manufacturing the electrolyte membrane 33 will be described.

1. 1. Film formation process An electrolyte film containing an ionic conductive ceramic material and an insulating organic polymer material is formed. The film forming method is not particularly limited, but for example, the simple dispersion method described below can be used.

First, a varnish is prepared by dissolving an organic polymer in a solvent. The solvent may be any solvent that can dissolve the organic polymer and can be evaporated after the film formation. Examples of the solvent include aprotonic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethylsulfoxide, or ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and propylene glycol monomethyl. Alkylene glycol monoalkyl ethers such as ether and propylene glycol monoethyl ether, halogen-based solvents such as dichloromethane and trichloroethane, and alcohols such as i-propyl alcohol and t-butyl alcohol can be used.

The mixture is then prepared by mixing the ceramic material with the prepared varnish. As a method for mixing the varnish and the ceramic material, for example, a stirrer method, a ball mill method, a jet mill method, a nanomill method, ultrasonic waves and the like can be used.

Next, the electrolyte film 33 can be produced by forming a film of a mixture of the varnish and the ceramic material on the substrate and then evaporating the solvent. The substrate may be any as long as the electrolyte membrane 33 can be peeled off after film formation, and for example, a glass plate, a polytetrafluoroethylene sheet, a polyimide sheet, or the like can be used. As a method for forming a film of the mixture, for example, a dip coating method, a spray coating method, a roll coating method, a doctor blade method, a gravure coating method, a screen printing method and the like can be used.

2. 2. Adsorption step Methanol or the like is adsorbed on the hydrophilic groups contained in the formed electrolyte membrane.

As a method for adsorbing methanol or the like on a hydrophilic group, a liquid phase adsorption method in which an electrolyte membrane is immersed in a liquid phase containing methanol or the like and water is chemically adsorbed on the hydrophilic group is preferable. The content of methanol or the like in the liquid phase can be 10 to 70 vol%, preferably 10 to 60 vol% in consideration of safety. The immersion time is not particularly limited, but can be 1 to 10 hours. The liquid temperature is preferably 20 to 70 ° C.

When the liquid phase adsorption method is used, the adsorption amount of methanol or the like can be controlled by adjusting at least one of the content of methanol and the like in the liquid phase, the immersion time and the liquid temperature. Therefore, if it is desired to shorten the immersion time without changing the adsorption amount of methanol or the like, the content of methanol or the like may be increased or the liquid temperature may be increased. Further, when it is desired to treat at a low temperature without changing the adsorption amount of methanol or the like, the content of methanol or the like may be increased or the immersion time may be lengthened. Further, when it is desired to reduce the content of methanol or the like without changing the adsorption amount of methanol or the like, the liquid temperature may be raised or the immersion time may be lengthened.

In addition, as a method of adsorbing methanol or the like on a hydrophilic group, a mixed solution containing methanol or the like and water is heated to generate a gas phase, and an electrolyte membrane is placed in the gas phase to form methanol on the hydrophilic group. A gas phase adsorption method for adsorbing or the like may be used. However, in the gas phase adsorption method, the above-mentioned liquid phase adsorption method is more preferable because water is likely to be preferentially adsorbed on the hydrophilic group.

When the gas phase adsorption method is used, the adsorption amount of methanol or the like can be controlled by adjusting at least one of the content of methanol and the like in the gas phase, the exposure time and the air temperature.

The amount of adsorbed methanol or the like adsorbed on the electrolyte membrane can be measured by the heated desorption mass spectrometry method, but it may not be possible to measure when the amount of adsorption is small.

3. 3. Drying step By drying the electrolyte membrane that has undergone the adsorption step, the water contained in the electrolyte membrane is evaporated. The drying method is not particularly limited, and the electrolyte membrane may be naturally dried, or the electrolyte membrane may be heated (40 to 90 ° C., 1 to 20 hours).

By repeating the above-mentioned adsorption step and drying step for two or more cycles, the number of hydrophilic groups adsorbed by methanol or the like can be increased, so that the decrease in the output of DMFC3 can be further suppressed.

(Modified example of the embodiment)
The present invention is not limited to the above embodiments, and various modifications or changes can be made without departing from the scope of the present invention.

(Modification 1) In the above embodiment, after the electrolyte membrane 33 in which methanol or the like is adsorbed on a hydrophilic group is produced, a cathode and an anode are formed on both sides of the electrolyte membrane 33, but methanol or the like is adsorbed. Methanol or the like may be adsorbed on the hydrophilic group after forming the cathode 31 and the anode 32 on both sides of the electrolyte membrane that has not been formed.

For example, after installing a laminate in which the cathode 31 and the anode 32 are formed on both sides of the electrolyte membrane in which methanol or the like is not adsorbed on the hydrophilic group is installed in the housing 2, methanol or the like and water are added to the anode 32 from the fuel supply unit 22. A mixed solution containing the above may be supplied in a liquid phase. In this case, by introducing methanol or the like into the electrolyte membrane via the anode 32, the electrolyte membrane 33 in which methanol or the like is adsorbed on the hydrophilic group is completed. After discharging the mixed liquid, the fuel supply unit 22 supplies the fuel containing methanol to the anode 32 in a gas phase when the DMFC 3 is operated.

Alternatively, a laminate in which the cathode 31 and the anode 32 are formed on both sides of the electrolyte membrane in which methanol or the like is not adsorbed on the hydrophilic group may be immersed in a mixed solution containing methanol or the like and water. In this case, by introducing methanol or the like into the electrolyte membrane via each of the cathode 31 and the anode 32, the electrolyte membrane 33 in which methanol or the like is adsorbed on the hydrophilic group is completed.

(Modification 2) In the above embodiment, the DMFC3, which is an alkaline fuel cell having a hydroxide ion as a carrier, has been described as an example of the DMFC, but the DMFC is not limited to this.

The DMFC may be a fuel cell having a proton as a carrier. In this case, an electrolyte membrane containing a ceramic material having proton conductivity and an organic polymer material having insulating properties may be used.

As the ceramic material having proton conductivity, a metal oxide hydrate having proton conductivity or the like can be used. Examples of such metal oxide hydrates include zirconium oxide hydrate, tungsten oxide hydrate, tin oxide hydrate, niobium-doped tungsten oxide, silicon oxide hydrate, and phosphoric acid oxide hydrate. Zirconium-doped silicon oxide hydrate, tonguestronic acid, molybdric acid and the like can be used.

(Modification 3) In the above embodiment, the case where the DMFC 3 is used as a single battery has been described, but a stack in which a plurality of DMFC 3s are stacked may be configured.

Examples of the present invention will be described. In the following examples, it is confirmed that the decrease in the output of the DMFC can be suppressed by adsorbing methanol or the like on the hydrophilic group contained in the electrolyte membrane. However, the present invention is not limited to the examples described below.

(Examples 1 to 9 and Comparative Examples 1 and 2)
First, LDH powder (average particle size 1.2 μm, 50 vol%) as an ionic conductive ceramic material and PVDF (manufactured by Kureha Corporation, 50 vol%) as an insulating organic polymer material are prepared and simply prepared. An electrolyte membrane (thickness 20 μm) was formed by the dispersion method.

Next, in Examples 1 to 6, methanol was adsorbed on the hydrophilic group contained in the electrolyte membrane by using the liquid phase adsorption method. The content of methanol and the like, the immersion time and the liquid temperature in the liquid phase were as shown in Table 1. In Examples 7 to 9, methanol was adsorbed on the hydrophilic group contained in the electrolyte membrane by using the vapor phase adsorption method. The content of methanol and the like, the exposure time and the air temperature in the gas phase were as shown in Table 1. On the other hand, in Comparative Examples 1 and 2, methanol was not adsorbed on the hydrophilic group contained in the electrolyte membrane.

Next, the electrolyte membranes of Examples 1 to 9 and Comparative Examples 1 and 2 were dried (50 ° C., 16 hours).

Next, Pt / C (Pt supporting amount 50 wt% (TEC10E50E manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) as a cathode catalyst) and PVDF powder as a binder were prepared. Then, a cathode catalyst: PVDF powder: weight of water was prepared. A cathode paste was prepared by mixing so that the ratio was 9 wt%: 0.9 wt%: 90 wt%, and the cathode paste was printed on one surface of the electrolyte membrane to form a cathode.

Next, Pt-Ru / C (Pt-Ru supported amount 54 wt% (TEC61E54 manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) as an anode catalyst) and PVDF powder as a binder were prepared, and a cathode catalyst: PVDF powder. An anode paste was prepared by mixing so that the weight ratio of water was 9 wt%: 0.9 wt%: 90 wt%, and the anode paste was printed on the other side of the electrolyte to form the anode. Formed.

As a result, the DMFCs according to Examples 1 to 9 and Comparative Examples 1 and 2 were completed.

(Measurement of OCV reduction rate)
An OCV (Open Circuit Voltage) test of the DMFC according to Examples 1 to 9 and Comparative Examples 1 and 2 was performed.

Specifically, after heating the alkaline fuel cell to 80 ° C., humidified air whose amount is adjusted so that the air utilization rate at the rated time is 50% is supplied to the cathode, and the fuel utilization rate at the rated time is 50. Vaporized methanol whose amount was adjusted to be% was supplied to the anode.

Then, OCV (initial OCV) was measured, energization was continued for 1 hour as it was, and then OCV (OCV after 1 hour) was measured again.

The rate of decrease in OCV after 1 hour with respect to the initial OCV was calculated as the rate of decrease in OCV. The calculation results are as shown in Table 1.

As shown in Table 1, in Examples 1 to 9 in which methanol was adsorbed on the hydrophilic group contained in the electrolyte membrane, the OCV reduction rate could be suppressed. From this, it was found that the decrease in the output of the fuel cell can be suppressed by adsorbing methanol on the hydrophilic group contained in the electrolyte membrane. Such a result was obtained by adsorbing methanol to the hydrophilic group contained in the electrolyte membrane in advance, so that the methanol as a fuel permeates the electrolyte membrane through the water adsorbed on the hydrophilic group. This is because I was able to suppress that.

Further, in Examples 1 to 6 using the liquid phase adsorption method, the OCV reduction rate could be further suppressed as compared with Examples 7 to 9 using the gas phase adsorption method. From this, it was found that the decrease in the output of the fuel cell can be further suppressed by using the liquid phase adsorption method. Such a result was obtained because the liquid phase adsorption method is less likely to preferentially adsorb water to the hydrophilic group than the gas phase adsorption method.

1 Direct methanol fuel cell system 2 Housing 21 Oxidizing agent supply 22 Fuel supply 3 Direct methanol fuel cell 31 Cathode 32 Anode 33 Electrolyte film

Claims (5)

A film forming process for forming an electrolyte film containing a ceramic material having ionic conductivity and an organic polymer material having insulating properties,
An adsorption step in which at least one of methanol and ethanol is adsorbed on the hydrophilic group contained in the electrolyte membrane.
A method for manufacturing an electrolyte membrane for a direct methanol fuel cell. In the adsorption step, at least one of methanol and ethanol is adsorbed on the hydrophilic group by immersing the electrolyte membrane in a liquid phase containing at least one of methanol and ethanol and water.
The method for manufacturing an electrolyte membrane for a direct methanol fuel cell according to claim 1. In the adsorption step, at least one of methanol and ethanol is adsorbed on the hydrophilic group by exposing the electrolyte membrane to a gas phase containing at least one of methanol and ethanol and water.
The method for manufacturing an electrolyte membrane for a direct methanol fuel cell according to claim 1. After the adsorption step, a step of drying the electrolyte membrane is further provided.
The method for producing an electrolyte membrane for a direct methanol fuel cell according to any one of claims 1 to 3. A direct methanol fuel cell having an anode, a cathode, and an electrolyte disposed between the anode and the cathode.
A housing having an oxidant supply unit that directly accommodates the methanol fuel cell and supplies an oxidant to the cathode, and a fuel supply unit that supplies fuel containing methanol to the anode.
Equipped with
The electrolyte contains a ceramic material having ionic conductivity and an organic polymer material having insulating properties.
Prior to the operation of the direct methanol fuel cell, the fuel supply unit supplies a liquid phase containing at least one of methanol and ethanol and water to the anode.
The fuel supply unit supplies the fuel to the anode in a gas phase during the operation of the direct methanol fuel cell.
Direct methanol fuel cell system.

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