WO2002021619A1

WO2002021619A1 - Solid polymer electrolytic fuel cell

Info

Publication number: WO2002021619A1
Application number: PCT/JP2000/005971
Authority: WO
Inventors: Kenji Yamaga; Toshiyuki Kobayashi; Yoshitaka Takezawa; Tomoichi Kamo
Original assignee: Hitachi, Ltd.
Priority date: 2000-09-01
Filing date: 2000-09-01
Publication date: 2002-03-14
Also published as: JPWO2002021619A1

Abstract

A solid polymer electrolytic fuel cell in which electrodes, gas introducing electrode diffusion layer, separators for preventing mixture of gases and ensuring current collection in the electrode surface and electrical connection in the direction of the thickness of the cell and for constituting the shell of a unit cell are provided on both sides of an electrolytic film containing a matrix serving as a film base material and a proton donor are provided in order, wherein noncrystalline polyolefin is used for the electrolytic film matrix.

Description

Description Solid polymer electrolyte fuel cell Technical field

The present invention relates to a solid polymer electrolyte fuel cell that extracts energy from a fuel and an oxidant by utilizing an electrochemical reaction. Background art

One of the features of the polymer electrolyte fuel cell (PEFC) is low-temperature operation.

As a realistic power supply system, a system is possible in which fossil fuels are refined to produce hydrogen, and the hydrogen is used to generate electricity using PEFC. However, in this system, the reformed gas contains by-products mainly composed of CO in the range of several hundred ppm to several%, and this CO is used as a platinum catalyst, which is a reaction field of the electrochemical reaction of PEFC. There is a problem that the performance of the battery decreases because the reaction is inhibited by selective adsorption on the surface (catalyst poisoning).

In order to reduce CO in reformed gas, it is possible to reduce it from several ppm to several tens of ppm by providing a CO removal device for the purpose of selective oxidation, etc. Another problem is that hydrogen reacts during the selective oxidation of CO, reducing efficiency.

The catalyst used in PEFC is mainly composed of platinum, but attempts have been made to improve its poisoning against CO by alloying with other metals. However, if batteries are continuously generated, performance degradation is currently unavoidable.

In particular, PEFC has a large reduction reaction polarization at the cathode. In order to improve the performance of PEFC, reduction of reaction polarization is a research topic.

As a means for solving these problems, it is effective to operate the battery at a high temperature. At the current operating temperature of PEFC, around 80, the CO tolerance is on the order of tens of ppm. For example, in a phosphoric acid fuel cell that operates at around 200 ° C, the CO capacity increases to a few percent. Also, as the temperature rises, the reaction rate of the chemical reaction also increases, so that the cathode reaction polarization is reduced and the battery voltage is expected to improve.

Furthermore, since the exhaust heat temperature recovered from the PEFC body rises as the operating temperature rises, a means of utilizing heat, which currently had only 40 to 70 ° C hot water supply, was added by an absorption refrigerator. It can generate valuable cold heat and can be adapted to produce steam for fuel reforming. This makes it possible to improve overall system efficiency.

However, high-temperature operation was almost impossible with the current configuration of PEFC. Although the electrolyte membrane currently used is Pas one Furuoroka one carbon polymer material typified by DuPont Nafuion ^TM, the glass transition point is in the order of 1 3 0 ° C, continuous operation at high temperatures the material properties Was difficult. In addition, in the electrolyte membrane currently used, the ionic conduction resistance increases as the water content decreases, so that the internal resistance increases and the cell performance deteriorates above 100 ° C where water boils. When the inside of the battery and the gas supply system are pressurized, the water content of the electrolyte membrane is improved, but auxiliary power to be supplied to the compressor for pressurization is required, which also complicates the system. There is a title.

Furthermore, the production process of the fluorine-based film is complicated, and the production equipment requires large-scale equipment. Therefore, the inevitably manufactured electrolyte membrane is also expensive. There was also a problem that it was not easily incinerated when discarded because it contained fluorine.

As a heat-resistant electrolyte membrane, for example, a phosphoric acid-impregnated polybenzimidazole (PBI) membrane is known (LT T. Wang, et al., Electrochim. Acta., 41, 193 (1996)). . This film has a heat resistance of more than 150 ° C, and its material cost is relatively low compared to Nafion. However, since phosphoric acid, which is a proton donor, is not fixed to the PBI substrate by a chemical bond, there is a problem that during long-term operation, phosphoric acid is dissipated and ionic resistance increases.

Development of proton conductive material by partially sulfonating heat-resistant plastic polyetheretherketone (PEEK) is also being conducted (USP 5, 362, 836). However, problems such as poor dimensional stability due to swelling of the material under operating conditions and poor mechanical strength are problems. Disclosure of the invention

The present invention includes the following inventions.

(1) A solid polymer electrolyte fuel cell using amorphous polyolefin as the electrolyte membrane matrix.

(2) An electrode, an electrode diffusion layer for conducting gas, and a gas mixture are prevented on both sides of the matrix as the membrane base material and the electrolyte membrane containing the proton donor to prevent gas mixing, and current collection and battery thickness within the electrode surface A solid polymer electrolyte fuel cell in which continuity in the direction is ensured and separators forming the outer shell of the unit cell are sequentially arranged, wherein the electrolyte membrane matrix is made of amorphous polyolefin. The solid polymer electrolyte fuel cell according to 1).

(3) The proton donor of the electrolyte membrane and the matrix are bonded via an atomic group in which at least an oxygen atom is bonded to one atom selected from Si, Ti and Zr. The polymer electrolyte fuel cell according to 2).

(4) The solid polymer electrolyte fuel cell according to (3), wherein the proton donor is a polyacid.

(5) The solid polymer electrolyte type according to (4), wherein the polyacid contains at least one selected from the group consisting of W, Si, Sn, Zn, P, and Mo as a central ion. Fuel cell.

(6) The solid polymer electrolyte fuel cell according to (3), wherein a silicon oxide containing at least P is used as the proton donor.

The solid polymer electrolyte fuel cell of the present invention is characterized in that amorphous polyolefin is used as a matrix as a base material of an electrolyte membrane. Here, the matrix is a main component of the electrolyte membrane, and a portion which is not included in proton conduction is generically represented. The material used as the matrix of the electrolyte membrane is required to have not only heat resistance but also acid resistance due to the operating conditions of the battery, and furthermore, material stability is required due to long operating time. In addition, if the electrolyte membrane breaks or cracks, the hydrogen and oxygen present in the reaction gas react directly with each other, so that the substrate has a certain degree of mechanical strength and flexibility even in a thinned state. Must be. Amorphous polyolefin is particularly suitable as a material satisfying such conditions.

Here, the amorphous polyolefin refers to a polymer having a crystallinity C (%) of 0 or more and 7 or less. Orefin. Here, C = dc '(d-dc) / (d' (dc-da)) (dc: density of crystal part, da: density of non-crystal part, d: density of sample). The amorphous polyolefin itself is a known material.

Examples of the amorphous polyolefin include a polymer having a cyclic structure described in JP-A-7-258504.

As the amorphous polyolefin having a cyclic structure, for example, the following formula:

-[-(A) _m — (CH ₂ — CH) _n —] one

I

R

[Wherein, m and n each independently represent an integer of 1 or more (preferably 1 to 1,000,000); R is a hydrogen atom, a halogen atom, or a substituted or unsubstituted hydrocarbon having 1 to 20 carbon atoms. A group (for example, an alkyl group, an alkoxyalkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, an alkoxyaryl group, a halogenated aryl group, an aralkyl group, or an alkoxyaralkyl group); Or an addition reaction product of a derivative thereof with norpolnadiene or a derivative thereof or a hydrogenated product thereof, or an addition reaction product of dicyclopentene or a derivative thereof with ethylene. ]

The polymer shown by these is mentioned.

The hydrogenated product of the addition reaction product of cyclopentene or its derivative with norpolnadiene or its derivative, or the addition product of dicyclopentene or its derivative with ethylene is represented by the following formula:

[In the formula, n is 1 or more integer (preferably 1 to 1 0000);! ¹ ~ ^ ^12, Each independently represents a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms (eg, an alkyl group, an alkenyl group, an aryl group, an aralkyl group), and R ¹ and R ² , R ⁵ and R ⁶ , R ⁹ and R ¹⁰ , R ¹¹ and R ¹² may each independently represent an alkylidene group having 1 to 20 carbon atoms, and R ^{9 to} R ¹² may be bonded to each other to form a monocyclic or polycyclic ring. You may. ]

Can be indicated by

, "" T

刖 d is a hydrogenated product of an addition reaction product with the derivative, and an addition reaction product of the derivative with ethylene is, for example, tetracyclo-3-dodecene,

8-methyltetracyclo-3-dodecene, 8-ethyltetracyclo-3-dodecene, 8-propyltetracyclo-3-dodecene, 8-butyltetracyclo-3-dodecene, 8-isobutyltetracyclo 3 _dodecene, 8-hexyltetracyclo-3-dodecene, 8-stearyltetracyclo-13-dodecene, 5,10-dimethyltetracyclo-3-dodecene, 2,10-dimethyltetracyclo-13-dodecene, 8,9-dimethyltetracyclo-3-dodecene, 8-ethyl-9-methyltetracyclo-13-dodecene, 11,12-dimethyltetracyclo-3-dodecene, 2,7,9-trimethyltetra Cyclo-3-dodecene, 9-ethyl-2,7-dimethyltetracyclo-3-dodecene, 9-isobutyl-2,7-dimethyltetracyclo-3-dodecene, 9,11,12-trimethyl Tetracyclo-3-dodecene, 9-ethyl-1-11,12-dimethyltetracyclo-3-dodecene, 9-isobutyl-11,12-dimethyltetracyclo-3-dodecene, 5,8,9,10-tetramethyltetracyclo-3 -Dodecene, 8-ethylidenetetracyclo-3-dodecene, 8-ethylidene-9-methyltetracyclo-3-dodecene, 8-ethylidene-9-ethyltetracyclo-3-dodecene, 8-ethylidene-9-isopropyl Tetracyclo-3-dodecene, 8-ethylidene-9-butyltetracyclo-3-dodecene, 8-n-propylidenetetracyclo-3-dodecene, 8-n-propylidene-9-methyltetracyclo-3-dodecene, 8 — N—propylidene-9-ethyltetracyclo-3-dodecene, 8-1-n-propylidene-9-isopropyltetracyclo-3-dodecene 8- n-propylidene - 9 one-butyl Tetracyclo-3-dodecene, 8-isopropylidenetetracyclo-3-dodecene, 8-isopropylidene-19-methyltetracyclo-13-dodecene, 8-isopropylidene-9-ethyltetracyclo-3-dodecene, 8-isopropylidene Ridene-1-9-isopropyltetracyclo-13-dodecene, 8-isopropylidene-9-butyltetracyclo-13-dodecene, 8-chlorotetracyclo-3-dodecene, 8-bromotetracyclo-3-dodecene, 8-full O-tetracyclo-3-dodecene, 8,9-dichlorotetracyclo-3-dodecene, hexacyclo-4-1-heptadecene, 12-methylhexacyclo-4-hephepdecene, 12-ethylhexacyclo-4 Heptane decene, 1,2-isobutylhexacyclo-41 Heptane decene, 1,6,10-trimethyl-12-isobuty Hexacyclo-41-decene, octacyclo-5-docosene, 15-methyl-cyclo-5-docosene, 15-ethylo-octacyclo-5-docosene, Pentacyclo 41-hexadecene, 1, 3-Dimethylpentylcyclo- 4-hexadecene, 1,6-dimethylpentylcyclohexadecane-1,15,16-Dimethylpentylcyclo-41-hexadecene, heptacyclo-5-eicosene, heptanecyclo- 5-Hen-eicosene, Penn-cyclo 4-pentadecene, 1,3-Dimethyl-pen-cyclo 4-pentadecene, 1,6-Di-methyl-pen-cyclo-1,4-penta-decene, 14-, 15-Dimethyl-penta-cyclo-41 Penyu decene, pentacyclo-14,10_penyu decadiene, and the like.

Other examples of the amorphous polyolefin include an addition reaction product of cyclopentene or a derivative thereof with norpolnadiene or a derivative thereof, and at least one unsaturated monomer selected from ethylene, butane, and a styrene derivative. And a copolymer thereof. Examples of the styrene derivative include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, ο-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-ethylstyrene, and m-methylstyrene. Ethyl styrene, ρ-ethyl styrene, p-methoxy styrene, p-chloroethyl styrene, p-methyl-α-methyl styrene and the like. These can be used in combination of two or more.

Another example of the amorphous polyolefin having a cyclic structure is represented by the following formula: CH ₉ — CH CH ゥ一 CH ₉

m

[Wherein, n represents 0 or an integer of 1 or more (preferably 1 to 100), m represents an integer of 1 or more (preferably 1 to 100), and R i R ⁴ Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms (eg, an alkyl group, an alkenyl group, a aryl group, and an aralkyl group). ]

And a hydrogenated product of a ring-opening polymer comprising tetracyclo-3-dodecene or a derivative thereof and bicyclohept-2-ene or a derivative thereof. The tetracyclo-3-dodecene or a derivative thereof includes, for example, tetracyclo-3-dodecene, 5,10-dimethyltetracyclo-3-dodecene, 2,10-dimethyltetracyclo-3-dodecene, 11, 12- Dimethyltetracyclo-3-dodecene, 2,7,9-trimethyltetracyclo-3-dodecene, 9-ethyl-2,7-dimethyltetracyclo-3-dodecene, 9-isobutyl-2,7-dimethyltetracyclo 3-dodecene, 9,11,12-trimethyltetracyclo3-dodecene, 91-ethyl-11,12-dimethyltetracyclo-13-dodecene, 9-^-sobutyl-11,12 -Dimethyltetracyclo-3-dodecene, 5,8,9,10-tetramethyltetracyclo-3-dodecene, 8-methyltetracyclo-3-dodecene, 8-ethyltetracyclo-3-dodecene 1,8-Propylthe-1, Lacyclo-3-dodecene, 8-1-hexyltetracyclo-3-dodecene, 8-Stearyltetracyclo-3-dodecene, 8,9-Dimethyltetracyclo-3-dodecene, 8— Methyl-9-ethyltetracyclo-3-dodecene, 8-cyclohexyltetracyclo-3-dodecene, 8-isobutyltetracyclo- 3._dodecene, 8-butyltetracyclo-3-dodecene, 8-ethylidene Tracyclo_3-dodecene, 8-ethylidene-9-methyltetracyclo-3-dodecene, 8-ethylidene-9-ethyltetracyclo-3-dodecene, 8-ethylidene-9-isopro Pyrtetracyclo-3-dodecene, 8-ethylidene-l-9-butyltetracyclo-3-dodecene, 8-n-propylidenetetracyclo-3-dodecene, 8-n-propylpyridene-1 9-methyltetracyclo-3 —Dodecene, 8-n-propylidene—9-ethyltetracyclo—3-dodecene, 8-n-propylidene—9-isopropyltetracyclo-13-dodecene, 8-n-propylidene-9-butyltetracyclo-3-dodecene , 8-Isopropylidenetetracyclo-3-dodecene, 8-Isopropylidene-l9-Methyltetracyclo-3-dodecene, 8-Isopropylidene-9-ethylethyltetracyclo-3-dodecene, 8-Isopropylidene-9-isopropylpropyltetracyclo- 3-dodecene, 8-isopropylidene-9-butyltetracyclo-3-dodecene and the like.

Examples of the bicyclohept-2-ene or a derivative thereof include, for example, bicyclohept-2-ene, 6-methylbicyclohept-12-ene, 5,6-dimethylbicyclohept-2-ene, 1 1-Methylbicyclohept-2-ene, 6-Ethylbicyclo Mouth Hept-2-ene, 6-n-Butylbicyclohept-1-ene, 6-Isobutylbicyclohept-2-ene, 7-Methylbicyclohept — 2-ene.

As the amorphous polyolefin, for example, the polymer having no cyclic structure described in JP-A-7-31622 can be used. Such amorphous polyolefins include, for example, polypropylene, propylene / ethylene copolymer, propylene / butene-1 copolymer, propylene 'butene-1' ethylene terpolymer, and propylene / hexene-1 copolymer. Octene-1 terpolymer, propylene'hexene1-1 / 4-methylpentene-11 terpolymer and polybutene-11. Among the above-mentioned amorphous polyolefins, polymers polymerized using norpolene or a norpolene derivative are materials with excellent heat resistance, acid resistance, and workability among amorphous olefins, and produce low-cost films. It also has the economics of doing so.

As the amorphous polyolefin used in the present invention, those having an average molecular weight of 50,000 to 300,000, a specific gravity of 1.1 or less, and a glass transition temperature (Tg) of 165 ° C. or more, which are measured by GPC, are preferable. . The amorphous polyolefin, e.g. § one ton ^TM (JSR Corp.), APOAPL ™ - 6 5 0 9 T ( Mitsui Chemicals, Inc.), Ubetakku ^TM UT 2 7 8 0 (Ube Veteran Ltd.) and the like of various Since the products are commercially available, they can be used.

The structure of the solid polymer electrolyte fuel cell of the present invention is not particularly limited. For example, an electrode and an electrode for guiding gas are provided on both sides of an electrolyte membrane containing a matrix serving as a membrane base material and a proton donor. An example is a structure in which a diffusion layer and a gas separator, which prevents gas mixing, ensures current collection in the electrode surface and conduction in the battery thickness direction, and forms an outer shell of the cell, are sequentially arranged.

In order to keep the ionic conduction resistance of the electrolyte membrane low at high temperatures for a long time, it is necessary to prevent electrolyte dissipation. From such a point, the proton donor of the electrolyte membrane and the matrix form an atomic group in which at least an oxygen atom and one atom selected from Si, Ti and Zr, preferably Si are bonded. It is preferable to use an electrolyte membrane that is bonded through the intermediary. As a result, the ion-exchange group is firmly fixed to the matrix, so that the phenomenon that the ion-exchange group is released outside the membrane with time and the resistance of the membrane increases can be greatly suppressed, and a longer life can be realized. .

When an inorganic substance and an organic substance are bonded by a chemical bond as described above, the use of a silane coupling agent is effective from the viewpoint of simplicity of synthesis and economy of reagent. In particular, when 3-isocyanatepropyltriethoxysilane is used, it is effective in heat resistance of the electrolyte membrane, stability in a battery environment, and suppression of ionic conductor dissipation, but is not limited thereto. .

As with the matrix, the proton donor that imparts ionic conductivity to the electrolyte membrane also requires heat resistance. In addition, since water has a boiling point of 10 O ^ C at normal pressure, the entire atmosphere must be pressurized to keep the membrane moist at higher temperatures. From such a point, it is preferable to use a metal oxide having proton conductivity as the proton donor, and it is preferable to use a polyacid as a material that exhibits good proton conductivity and does not deteriorate in ionic conductivity even at a high temperature. More preferred.

As the polyacid, those containing at least one selected from the group consisting of W, Si, Sn, Zn, P and Mo as a central ion are preferable.

Polyacids include not only isopolyacids but also heteroatoms containing two or more central ions. Polyacids can be used. The isopolyacids, for example iso Poritan Dasute phosphate hydrate, iso poly molybdate hydrate, tin oxide hydrate (S n0 _₂ * nH ₂ 〇). Examples of the heteropoly acid, e.g. Kei tungstate Hydrates.

These polyacids retain water molecules in the form of water of hydration on the material itself, or adsorb them on the surface of the material, etc., so that sufficient ionic conductivity can be ensured even at low relative humidity under high temperature conditions. it can. In other words, even at the operating temperature of 100 or more, it is not necessary to raise the battery environment to the saturated steam pressure at that temperature, so that less energy is consumed by the trapping device such as the compressor than in the past, and that much. System efficiency can be expected.

By using these proton conductive materials, the resistance is low even under high temperature conditions, and the amount of water vapor for wetting the electrolyte membrane can be kept low. This is because the material itself holds water molecules in the form of water of hydration, or adsorbs it on the surface of the material, so that a proton conduction path can be secured even in an environment with low relative humidity. This allows the operating pressure of the battery to be set low, which is effective in simplifying the system configuration.

As the metal oxide having proton conductivity used as the proton donor, at least silicon oxide containing P can be used. In particular, phosphate glass has high heat resistance (e.g., P 2 O ₅ · y S I_〇 _{_{_{2, xP 2 0 5 - yZ}}} r 0 2 - in z S I_〇 ₂ (here, x, y and z is represents any number.), high temperature stability as an electrolyte membrane by using a more specifically include compositions such as _{_{5 P 2 0 5 · 5 Z}} r 0 2 · 90 S i 0 2.) Can be further improved. At this time, the phosphoric acid-based glass preferably has a porous structure in order to increase the amount of adsorbed water and adsorbed hydroxyl groups serving as proton conduction paths and the amount of water contained therein.

FIG. 1 shows a typical structure of an electrolyte membrane constituting a solid polymer electrolyte fuel cell of the present invention. It has a structure in which a substituent R ₂ is bonded to an amorphous polyolefin main chain. Where R ₂ is

-ii-S i R ₁₂ -〇— R ₁₃ —

— R 2 i ^— l R ₂₂ —〇— 23 one P 2 Or a hydrogen atom. However, there is no case where and R ₂ are both hydrogen atoms. R _1X and R _2X are atomic groups composed of an organic material, and P _x is a proton donor. R _1X and R _2X may be omitted. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic structural diagram of an electrolyte membrane constituting a solid polymer electrolyte fuel cell of the present invention. FIG. 2 is a diagram showing changes over time in cell voltage in Examples 1 and 2 and a comparative example. FIG. 3 is a diagram showing relative humidity and resistance of supply gas of Examples 1 and 2 and Comparative Example. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

(Example 1)

Electrolyte membrane matrix material as J SR Inc. Art ^TM (specific gravity 1.08, glass transition temperature 17 1, the thermal conductivity of 0. lekcal Zm 'hr' ^) 4 single glass powder 80 g of toluene 220 m 1 The mixture was added to a neck flask, and stirred under a nitrogen atmosphere to obtain an electrolyte membrane matrix solution a. 8 g of 3f succinatepropyltriethoxysilane was added to solution a, and the mixture was stirred under reflux at 75 ° C. under a nitrogen atmosphere for 24 hours to prepare solution b.

A solution c in which 16 g of kytungstic acid hydrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in methanol 3 Om1 was added to solution b, and stirred to prepare an electrolyte solution c '. The resultant was developed into a film having a thickness of m and dried in air at 75 ° C for 10 hours to obtain an electrolyte membrane d. Even when the electrolyte membrane was left in a boiling aqueous solution, no change was observed in the proton concentration of the solution. This is because kytungstic acid, which is an ion exchange group, is chemically fixed to the matrix by coupling.

A catalyst paste e was prepared by mixing 2.5 g of a catalyst obtained by depositing fine platinum particles on carbon powder and 90 g of an electrolyte solution c ′. The catalyst paste e was spread on the surface of the electrolyte membrane d by screen printing into a square thin film having a side of 10 cm to form a catalyst layer. At this time, the spreading amount, that is, the catalyst layer thickness was adjusted so that the amount of platinum used was 0.3 mg per 1 cm ^{2 of the} coated catalyst area. Apply catalyst layer on both sides of electrolyte membrane d Thereafter, a drying treatment was performed at 75 ° C. for 10 hours in a nitrogen atmosphere. This treatment has the meaning of dispersing the solvent in the catalyst layer and promoting the gelling reaction of the electrolyte membrane base in the catalyst layer. By the above method, an electrolyte membrane having a catalyst layer having an area of 100 cm ² formed on the front and back surfaces, that is, a so-called integrated electrode f was obtained.

An electrode diffusion layer (Carbon-CL, manufactured by Japan Gortex Co., Ltd.), which also has a current collecting function, is placed on both sides of the catalyst surface of this integrated electrode f, and a single cell for testing is combined with a carbon separator that forms a gas flow path. And This cell is referred to as a first embodiment. This single cell was placed in a thermostat, and hydrogen was supplied as anode gas and air was supplied as power source gas, and a power generation test was performed. The anode gas and cathodic gas were humidified by passing through a temperature-adjustable bubbler, preventing an increase in ion conduction resistance due to drying of the electrolyte membrane. Pressure regulating valves are provided at the gas line outlets of the anode and cathode, respectively, so that gas humidification can be performed even at a cell temperature of 100 ° C or more. In the power generation test, the cell temperature was set at 130 ° C, and the humidification temperature of the anode gas and the force gas was also set at 130 ° C.

(Example 2)

As an electrolyte membrane matrix material, 80 g of Arton ¹ ^ (specific gravity: 1.08, glass transition temperature: 171 ° (thermal conductivity: 0.16 kca 1 Zm · hr · ° C) manufactured by JSR Corporation) 220 ml of toluene was added to a glass four-necked flask, and stirred under a nitrogen atmosphere to obtain an electrolyte membrane matrix solution a.8 g of 3-isocyanatepropyltriethoxysilane was added to the solution a, and the solution was added at 75 ° C. The mixture was refluxed and mixed under a nitrogen atmosphere for 24 hours to prepare a solution b.

To 200 g of PO [OCH (CH ₃ ) ₂ ] 3 -x (OH) _x 100 g of isopropanol and 58 g of ethyl ethyl orthoethylate (Si (OC ₂ H ₅ ) ₄ ) were added, and nitrogen was added at 70 ° C. The mixture was stirred for 5 hours under an atmosphere to prepare a solution g. To the solution g, 0.1 IN hydrochloric acid was added as an acid catalyst to obtain a solution h. After heating the solution h at 100 ° C for 10 hours, it was further subjected to a heat treatment at 500 ° C for 24 hours to obtain a phosphate glass i.

50 g of solution b was added to 25 g of phosphoric acid-based glass i crushed by a pole mill for 5 hours, and 0.1 N hydrochloric acid was added to prepare an electrolyte solution j. Spread solution j into a 50 m thick film by tape casting method, and dry in air at 75 ° C for 10 hours. An electrolyte membrane k was obtained.

Thereafter, an integrated electrode 1 was produced in the same manner as in Example 1, and was assembled in a small cell and subjected to a power generation test. This cell was designated as Example 2.

(Comparative example)

As in Example 1, 20 g of a catalyst in which platinum fine particles were precipitated on carbon particles and 400 g of a 5 wt% solution of Nafion ^™ were kneaded to prepare a catalyst paste. After adding methanol for viscosity adjustment to adjust the paste viscosity to 50 cP, a catalyst layer was formed on the surface of Nafion ^TM 117 (manufactured by Dupont) in the form of a thin film by a screen printing method. At this time, the amount of platinum was adjusted so that the amount of platinum used was 0.3 mg per 1 cm ^{2 of the} coated catalyst area. After drying at 75 ° C for 10 hours in a nitrogen atmosphere, a catalyst layer was formed on the opposite surface in the same manner as above to obtain an integrated electrode m. An electrode diffusion layer (CARBEL-CL, manufactured by Japan Gore-Tex Corporation) and a carbon separator were arranged on the integrated electrode m to form a single cell. This cell was used as a comparative example. Humidified hydrogen and humidified air were supplied to the comparative example cell, and a power generation test was performed at a cell temperature of 130 ° C.

FIG. 2 shows the change over time in the cell voltage when a current of 0.5 A was applied per 1 cm ² of electrode area for Examples 1, 2 and Comparative Example. In Comparative Example 1, the battery voltage was reduced after several hundred hours under the operating condition of 130 ° C. This is probably because the water content of the electrolyte membrane decreased and the proton conductivity increased under high temperature conditions and low relative humidity. Furthermore, the perfluorocarbon sulfonic acid-based electrolyte membrane has a structure in which a hydrophilic group forms a cluster structure to secure a proton channel. This is also due to the increase in

On the other hand, in Examples 1 and 2, there was almost no decrease in the battery voltage at 3000 hours during the power generation test. It is considered that the electrolyte membranes of Examples 1 and 2 have excellent heat resistance of the membrane base material and the ion conductor, and that the materials are strongly bonded to each other.

FIG. 3 shows the results of measuring the conductivity of Examples 1, 2 and Comparative Example when the relative humidity of the supply gas was changed at 130 ° C. The conductivity was evaluated by an AC 1 kHz four-terminal method. The conductivity of the electrolyte membrane of the comparative example decreases sharply at low relative humidity. Was. This is because this membrane shows proton conductivity only when water molecules are hydrated to sulfonic acid groups which are proton donating groups present in the membrane. Therefore, at low relative humidity where the water content of the membrane decreases, the ionic conduction resistance increases, which is unsuitable as an electrolyte membrane for a high-temperature operated battery.

On the other hand, in Example 1, even at a relative humidity of 40%, the ionic conduction resistance hardly changed from that at a relative humidity of 100%, and the rate of increase from the lowest resistance value was within 10%. This is due to the fact that water molecules are stably present in the form of hydration in the kytungstic acid used as the proton conductor, so that protons conduct through the hydrated water as a mobile channel.

This tendency was the same in Example 2, and the relative humidity dependence of the conductivity was smaller than in Example 1. This is because the phosphoric acid-based glass, which is the proton conductor used in Example 2, adsorbs and contains water and hydroxyl groups on its surface and inside. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety. Industrial applicability

According to the present invention, it is possible to operate a fuel cell at a high temperature, to improve the CO poisoning resistance of the electrode catalyst, to improve the performance by reducing the reaction resistance of the force sword reaction, and to reduce the exhaust heat of the cell as one of the heat sources of the fuel reforming section. It is possible to improve the system efficiency by collecting it in the section.

Claims

The scope of the claims

1. Solid polymer electrolyte fuel cell using amorphous polyolefin for the electrolyte membrane matrix.

2. Electrodes, an electrode diffusion layer that conducts gas, and a gas mixture are prevented on both sides of the electrolyte membrane containing the matrix and proton donor, which serve as the membrane base material, to prevent gas mixing and to collect electricity in the electrode plane and increase the thickness of the battery. Claims 1. A solid polymer electrolyte fuel cell in which conduction is ensured and a separator that forms an outer shell of a unit cell is sequentially disposed, wherein amorphous polyolefin is used for the electrolyte membrane matrix. Polymer electrolyte fuel cell

3. The proton donor of the electrolyte membrane and the matrix are bonded via an atomic group in which at least an oxygen atom is bonded to one atom selected from Si, Ti and Zr. 3. The solid polymer electrolyte fuel cell according to item 2.

4. The solid polymer electrolyte fuel cell according to claim 3, wherein the proton donor is a polyacid.

5. The solid polymer electrolyte according to claim 4, wherein the polyacid contains at least one selected from the group consisting of W, Si, Sn, Zn, P, and Mo as a central ion. Quality fuel cell.

6. The solid polymer electrolyte fuel cell according to claim 3, wherein a silicon oxide containing at least P is used as the proton donor.