JP5968737B2 - Manufacturing method of fuel cell - Google Patents

Description

  The present invention relates to a method for manufacturing a fuel cell, and more particularly to a method for manufacturing a fuel cell to which liquid fuel is supplied.

  Conventionally, various fuel cells such as alkaline type (AFC), solid polymer type (PEFC), phosphoric acid type (PAFC), molten carbonate type (MCFC), and solid electrolyte type (SOFC) are known as fuel cells. Yes. These fuel cells are being studied for use in various applications such as automobile applications.

  For example, a polymer electrolyte fuel cell includes a fuel-side electrode (anode catalyst layer) to which fuel is supplied and an oxygen-side electrode (cathode catalyst layer) to which oxygen is supplied. Oppositely arranged with an electrolyte layer made of a polymer membrane in between.

  Specifically, such a polymer electrolyte fuel cell includes an electrolyte layer made of an anion exchange membrane, and a fuel side electrode and an oxygen side electrode that are arranged to face each other with the electrolyte layer interposed therebetween, and hydrazines as a fuel There is known a fuel cell in which the liquid fuel is supplied and the fuel side electrode is formed of a fine powder of a metal such as cobalt (for example, see Patent Document 1).

  In such a fuel cell, it is also known that the oxygen-side electrode is formed from a fine powder of a single metal (see, for example, Patent Document 2).

  In such a fuel cell, fuel is supplied to the fuel side electrode and air is supplied to the oxygen side electrode, whereby an electromotive force is generated between the fuel side electrode and the oxygen side electrode.

JP 2006-244961 A JP 2006-244960 A

  However, the simple metal used for the fuel-side electrode and / or the oxygen-side electrode of such a fuel cell is usually obtained by reducing and firing a metal precursor (metal salt or the like). Aggregation may reduce the specific surface area, which may cause a decrease in power generation performance.

  In addition, since the above method requires a step of reducing and firing the metal salt, it is required to manufacture a fuel cell more simply and at low cost.

  Accordingly, an object of the present invention is to provide a method of manufacturing a fuel cell, which can obtain a fuel cell excellent in power generation performance easily and at low cost.

  In order to achieve the above object, a method for producing a fuel cell according to the present invention includes an ink preparation step of preparing an electrode ink containing a metal precursor that is converted into a simple metal by reduction, and applying the electrode ink to an electrolyte layer. A cell forming step of forming an electrode and obtaining a fuel cell, an assembly step of stacking a plurality of the fuel cells to obtain a cell laminate, and a liquid capable of reducing the metal precursor to the cell laminate It includes a reduction step of supplying fuel and reducing the metal precursor.

  In the method for producing a fuel cell of the present invention, first, an electrode ink containing a metal precursor that becomes a metal simple substance by reduction is applied to an electrolyte layer, and after an electrode is formed, a cell laminate including such an electrode is used. Liquid fuel is supplied, and the metal precursor is reduced and metalized.

  That is, in such a fuel cell manufacturing method, a simple metal can be obtained without the reduction firing step.

  Therefore, the fuel cell obtained in this way can be provided with excellent power generation performance because the single metal is highly dispersed in the electrode without being agglomerated.

  Furthermore, in the fuel cell manufacturing method of the present invention, by supplying liquid fuel, it is possible to generate power in the cell stack and reduce the metal precursor to obtain a single metal.

  Therefore, in the method for producing a fuel cell according to the present invention, a separate step of reducing and firing the metal precursor is not required at the time of producing the fuel cell, and the fuel cell can be obtained simply and at low cost.

FIG. 1 is a schematic configuration diagram showing a fuel cell obtained by an embodiment of a fuel cell manufacturing method of the present invention. FIG. 2 is a process diagram showing one embodiment of a method for producing a fuel cell of the present invention, wherein (a) is a process for preparing an electrode ink containing a metal precursor, and (b) is a process for preparing an electrolyte layer. The steps of forming a fuel side electrode on one side and forming an oxygen side electrode on the other side of the electrolyte layer to obtain a fuel cell are shown respectively. FIG. 3 is a process diagram showing an embodiment of the method for producing a fuel cell of the present invention, following FIG. 2, wherein (c) is a process of stacking a plurality of fuel cells to obtain a cell stack, (D) shows the process of supplying the liquid fuel which can reduce | restore a metal precursor with respect to a cell laminated body, and reducing a metal precursor, and making a metal precursor into a metal simple substance, respectively.

  FIG. 1 is a schematic configuration diagram showing a fuel cell obtained by an embodiment of a fuel cell manufacturing method of the present invention.

  In FIG. 1, a fuel cell 1 is a polymer electrolyte fuel cell, and includes a plurality of fuel cells S, and a stack structure in which these fuel cells S are stacked (cell stack 15 (described later)). ).

  In FIG. 1, one fuel cell S is taken out for easy illustration.

  The fuel cell S includes an electrolyte layer 4, a fuel side electrode 2 as an electrode formed on one side surface of the electrolyte layer 4, and an oxygen side electrode 3 as an electrode formed on the other side surface of the electrolyte layer 4. Yes.

  The electrolyte layer 4 is a layer in which an anion component can move, and is formed using, for example, an anion exchange membrane.

The anion exchange membrane is not particularly limited as long as it is a medium in which an anion component (for example, hydroxide ion (OH ⁻ )) can move, and for example, an anion exchange group such as a quaternary ammonium group or a pyridinium group can be used. And a solid polymer membrane (anion exchange resin).

  Examples of the solid polymer forming the anion exchange membrane include hydrocarbon-based solid polymer membranes such as polystyrene and modified products thereof.

  The solid polymer forming the anion exchange membrane may have a cross-linked structure in its molecular structure.

  Moreover, an anion exchange membrane is available as a commercial item, for example, Selemion (made by Asahi Glass Co., Ltd.), Neoceptor (made by Astom Corp.), etc. are mentioned.

  Moreover, the film thickness of the electrolyte layer 4 is 10-100 micrometers, for example.

  The fuel side electrode 2 is formed of, for example, an electrode material such as a catalyst carrier carrying a catalyst. Alternatively, a catalyst may be used as the electrode material without using the catalyst carrier, and the catalyst may be formed directly as the fuel-side electrode 2.

  The catalyst is not particularly limited, and examples thereof include platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt)), iron group elements ( According to a periodic table such as iron (Fe), cobalt (Co), nickel (Ni)) (IUPAC Periodic Table of the Elements (version date 22 June 2007), the same applies hereinafter) Group 8 to 10 (VIII) elements, For example, simple metals such as Group 11 (IB) elements of the periodic table such as copper (Cu), silver (Ag), and gold (Au) can be used.

  These can be used alone or in combination of two or more.

  Examples of the catalyst carrier include porous substances such as carbon.

  The amount of the catalyst supported on the catalyst carrier is not particularly limited, and is appropriately set according to the purpose and application.

  The thickness of the fuel side electrode 2 is, for example, 10 to 200 μm, preferably 20 to 100 μm.

  The oxygen side electrode 3 is formed of, for example, an electrode material such as a catalyst carrier carrying a catalyst, similarly to the fuel side electrode 2 described above. Alternatively, a catalyst may be used as the electrode material without using the catalyst carrier, and the catalyst may be formed directly as the oxygen side electrode 3.

  In the oxygen-side electrode 3, as the electrode material, for example, a complex formed of a complex-forming organic compound and / or a conductive polymer and carbon (hereinafter, this complex is referred to as “carbon composite”), a transition metal. A catalyst on which is supported can also be used.

  Examples of the transition metal include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu ), Yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), lanthanum (La) ), Hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and the like. Among these, Preferably, silver and cobalt are mentioned. These may be used alone or in combination of two or more.

  A complex-forming organic compound is an organic compound that forms a complex with a metal atom by coordinating with the metal atom. And complex-forming organic compounds such as these or polymers thereof. Among these, Preferably, the polypyrrole which is a polymer of pyrrole is mentioned. These may be used alone or in combination of two or more.

  As the conductive polymer, there is a compound overlapping with the above complex-forming organic compound, for example, polyaniline, polypyrrole, polythiophene, polyacetylene, polyvinylcarbazole, polytriphenylamine, polypyridine, polypyrimidine, polyquinoxaline, polyphenylquinoxaline, Examples include polyisothianaphthene, polypyridinediyl, polythienylene, polyparaphenylene, polyflurane, polyacene, polyfuran, polyazulene, polyindole, and polydiaminoanthraquinone. Among these, Preferably, a polypyrrole is mentioned. These may be used alone or in combination of two or more.

  The thickness of the oxygen side electrode 3 is, for example, 10 to 300 μm, preferably 20 to 150 μm.

  Further, in this fuel cell S, as a material of at least one of the fuel side electrode 2 and the oxygen side electrode 3 described above, a metal simple substance (a catalyst not supported on the catalyst carrier) is used.

  Preferably, a metal simple substance is used as the electrode material of the fuel side electrode 2.

  If the metal simple substance is contained in the fuel side electrode 2, the liquid fuel can be diffused into the fuel side electrode 2 with excellent efficiency, and excellent power generation performance can be obtained.

  Preferably, a catalyst in which a transition metal is supported on a carbon composite is used as the electrode material of the oxygen side electrode 3.

  If the catalyst in which the transition metal is supported on the carbon composite is contained in the oxygen-side electrode 3, excellent power generation performance can be obtained.

  The fuel cell S further includes a fuel supply member 5 and an oxygen supply member 6.

  The fuel supply member 5 is made of a gas impermeable conductive member, and one surface thereof is opposed to the surface of the fuel side electrode 2 opposite to the surface in contact with the electrolyte layer 4. . The fuel supply member 5 is formed with a fuel-side flow path 7 for bringing fuel into contact with the entire fuel-side electrode 2 as a distorted groove recessed from one surface. The fuel-side flow path 7 has a supply port 8 and a discharge port 9 that pass through the fuel supply member 5 formed continuously at the upstream end and the downstream end, respectively.

  Similarly to the fuel supply member 5, the oxygen supply member 6 is made of a gas impermeable conductive member, and one surface thereof is opposite to the surface in contact with the electrolyte layer 4 in the oxygen side electrode 3. Opposite contact is made with the side surface. The oxygen supply member 6 is also formed with an oxygen-side flow channel 10 for contacting oxygen (air) with the entire oxygen-side electrode 3 as a distorted groove recessed from one surface. The oxygen-side flow path 10 also has a supply port 11 and a discharge port 12 that pass through the oxygen supply member 6 continuously formed at the upstream end portion and the downstream end portion thereof.

  The fuel cell 1 is formed as a stack structure in which a plurality of fuel cells S are stacked as described above. Therefore, although not shown, the fuel supply member 5 and the oxygen supply member 6 are configured (also used) as separators in which the fuel side flow path 7 and the oxygen side flow path 10 are formed on both surfaces.

  Although not shown in FIG. 1, the fuel cell 1 is provided with a current collector plate formed of a conductive material, and the electromotive force generated in the fuel cell 1 is provided in the current collector plate. It is taken out from the terminal.

  Further, on a test (model) basis, the fuel supply member 5 and the oxygen supply member 6 are connected by an external circuit 13, and a voltmeter 14 is interposed in the external circuit 13, thereby generating the fuel cell 1. The voltage can also be measured.

  FIG. 2 is a process diagram showing an embodiment of a method for producing a fuel cell of the present invention, and FIG. 3 is a process diagram showing an embodiment of a method for producing a fuel cell of the present invention following FIG.

  Below, the manufacturing method of the fuel cell 1 for manufacturing such a fuel cell 1 is explained in full detail with reference to FIG. 2 and FIG.

  In this method, first, as shown in FIG. 2A, an electrode ink containing a metal precursor that is converted into a simple metal by reduction is prepared (ink preparation step).

  More specifically, first, a fuel side electrode ink used for forming the fuel side electrode 2 is prepared.

  In the preparation of the fuel side electrode ink, for example, a metal precursor that becomes a metal simple substance by reduction and a solvent are mixed and stirred.

  The metal precursor that is converted into a simple metal by reduction is a compound that becomes a simple metal as described above by reduction, and examples thereof include nitrates, hydroxides, acetates, and the like of the simple metal described above, preferably And nitrates of simple metals.

  These metal precursors can be used alone or in combination of two or more.

  Examples of the solvent include known solvents such as lower alcohols such as methanol, ethanol and 1-propanol, ethers such as tetrahydrofuran, and water. These solvents can be used alone or in combination of two or more.

  The mixing ratio of these components is, for example, 50 parts by mass or more, preferably 180 parts by mass or more, for example, 300 parts by mass or less, preferably 190 parts by mass with respect to 100 parts by mass of the metal precursor. Or less.

  A known mixing method is employed as the mixing method. The mixing temperature is, for example, 10 to 30 ° C., and the mixing time is, for example, 1 to 60 minutes.

  Thereby, fuel side electrode ink can be prepared.

  In addition, the fuel-side electrode ink further includes, for example, an ionomer for highly dispersing the electrode material and further improving ion conductivity and adhesion, and a resin component for imparting water repellency (for example, polytetrafluoro Known additives such as ethylene (PTFE) and the like can be added. In addition, the mixture ratio of an additive is not restrict | limited in particular, According to the objective and a use, it sets suitably.

  In this ink preparation step, oxygen-side electrode ink used for forming the oxygen-side electrode 3 is prepared separately from the fuel-side electrode ink.

  In the preparation of the oxygen side electrode ink, the electrode material and the solvent are mixed and stirred.

  The mixing ratio of these components is, for example, 1000 parts by mass or more, preferably 1600 parts by mass or more, for example, 2500 parts by mass or less, preferably 1700 parts by mass with respect to 100 parts by mass of the electrode material. It is as follows.

  Moreover, a well-known mixing method is employ | adopted as a mixing method. The mixing temperature is, for example, 10 to 30 ° C., and the mixing time is, for example, 1 to 60 minutes.

  Thereby, oxygen side electrode ink can be prepared.

  Similarly to the fuel-side electrode ink, the oxygen-side electrode ink is further added with a known additive such as an ionomer or a water repellency imparting resin (for example, polytetrafluoroethylene (PTFE)) in an appropriate ratio. Can be added.

  Next, in this method, as shown in FIG. 2B, the fuel side electrode 2 is formed on one side surface of the electrolyte layer 4, and the oxygen side electrode 3 is formed on the other side surface of the electrolyte layer 4. S is obtained (cell formation step).

  In order to form the fuel side electrode 2 on one side surface of the electrolyte layer 4, first, the fuel side electrode ink obtained as described above is formed so as to cover one surface of the electrolyte layer 4, for example, at room temperature and normal pressure. Apply.

  Examples of the application method of the fuel side electrode ink include known application methods such as a spray method, a die coater method, and an ink jet method, and preferably a spray method.

  Thereafter, the applied fuel-side electrode ink is dried at 10 to 40 ° C., for example.

  Thereby, the fuel side electrode 2 containing a metal precursor can be formed on one surface of the electrolyte layer 4.

  As described above, the thickness of the fuel side electrode 2 is, for example, 10 to 200 μm, preferably 20 to 100 μm.

Moreover, the loading amount of electrode material (metal simple substance conversion) is 0.01 mg / cm ² or more and 10 mg / cm ² or less.

  In order to form the oxygen side electrode 3 on the other side surface of the electrolyte layer 4, the oxygen side electrode ink is applied to the other surface of the electrolyte layer 4 (the other side of the one on which the fuel side electrode 2 is fixed) by the same method as described above. Apply and dry.

  Thereby, the oxygen-side electrode 3 can be formed on the other surface of the electrolyte layer 4.

  As described above, the oxygen side electrode 3 has a thickness of, for example, 10 to 300 μm, preferably 20 to 150 μm.

The amount of the electrode material supported is, for example, 0.09 mg / cm ² or more, preferably 0.18 mg / cm ² or more, for example, 18 mg / cm ² or less, preferably 9 mg / cm ² or less. .

  And by forming the fuel side electrode 2 and the oxygen side electrode 3 in this way, the fuel cell S can be obtained as a membrane-electrode assembly.

  Next, in this method, as shown in FIG. 3C, a plurality of the fuel cells S obtained as described above are stacked to obtain a cell stack 15 (assembly process).

  That is, in this step, first, a plurality (for example, 2 to 500) of the fuel cells S are prepared. Then, a plurality of fuel cells S are sequentially stacked so that the separators 5 and 6 that also serve as the fuel supply member 5 and the oxygen supply member 6 are interposed between the fuel cells S. Thereby, the cell stack 15 (see FIG. 1) is obtained.

  Although not shown, in the cell laminate 15, a known gas diffusion layer or the like can be laminated together with the fuel cell S and the separators 5 and 6, and a gasket or the like can be provided as necessary. it can.

  Next, in this method, as shown in FIG. 3 (d), the fuel side electrode 2 is supplied by supplying a liquid fuel capable of reducing the metal precursor to the cell stack 15 and reducing the metal precursor. The metal precursor is made into a single metal (reduction process).

  That is, as will be described in detail later, the liquid fuel (described later) is prepared so that the metal precursor can be reduced. Then, such a liquid fuel (described later) is supplied to the fuel-side electrode 2 of the cell stack 15 at an appropriate flow rate, whereby the metal precursor is reduced to form a single metal. Thereby, the fuel cell 1 in which the metal simple substance is highly dispersed in the fuel side electrode 2 can be obtained.

  Then, the liquid fuel (described later) supplied to the fuel side electrode 2 reacts as described later, and generates electric power in the cell stack 15.

  Next, power generation by the fuel cell 1 will be described.

  In the fuel cell 1, air is supplied to the oxygen-side flow path 10, and liquid fuel containing a fuel compound (hereinafter sometimes simply referred to as “fuel”) is supplied to the fuel-side flow path 7. As a result, power is generated.

  In this fuel cell 1, the liquid fuel supplied to the fuel side flow path 7 is prepared so that the metal precursor can be reduced.

Examples of such a liquid fuel include a liquid fuel containing hydrazines. Specifically, for example, anhydrous hydrazine (NH ₂ NH ₂ ), hydrated hydrazine (NH ₂ NH ₂ .H ₂ O), and the like. An aqueous solution of hydrazines such as triazane (NH ₂ NHNH ₂ ), tetrazane (NH ₂ NHNHNH ₂ ), and the like.

  Further, for example, alkali metal hydroxides such as potassium hydroxide and sodium hydroxide can be added to the liquid fuel as additives. The addition amount of the additive is not particularly limited, and is appropriately set according to the purpose and application.

  The fuel compound may be supplied as it is, or may be supplied as a solution of water and / or alcohol (for example, lower alcohols such as methanol, ethanol, propanol, isopropanol). In this case, the concentration of the fuel compound in the solution varies depending on the type of the fuel compound, but is, for example, 1 to 90% by mass, preferably 1 to 30% by mass.

The power generation in the fuel cell 1 will be described more specifically. While supplying oxygen (air) to the oxygen side channel 10 of the oxygen supply member 6, the fuel described above is supplied to the fuel side channel 7 of the fuel supply member 5. In the oxygen side electrode 3, electrons (e ⁻ ), water (H ₂ O), oxygen, which are generated in the fuel side electrode 2 and move via the external circuit 13, as described below, are supplied. Reaction with (O ₂ ) produces hydroxide ions (OH ⁻ ). The generated hydroxide ions (OH ⁻ ) move from the oxygen side electrode 3 to the fuel side electrode 2 through the electrolyte layer 4 made of an anion exchange membrane. In the fuel-side electrode 2, the hydroxide ions (OH ⁻ ) that have passed through the electrolyte layer 4 react with the fuel to generate electrons (e ⁻ ). The generated electrons (e ⁻ ) are moved from the fuel supply member 5 to the oxygen supply member 6 via the external circuit 13 and supplied to the oxygen side electrode 3. An electromotive force is generated by such an electrochemical reaction in the fuel side electrode 2 and the oxygen side electrode 3, and power generation is performed.

For example, when hydrazine (NH ₂ NH ₂ ) is used as the fuel, the above reaction can be expressed by the following reaction formulas (1) to (3) as the fuel side electrode 2, the oxygen side electrode 3 and the whole. it can.
(1) NH ₂ NH ₂ + 4OH ⁻ → 4H ₂ O + N ₂ + 4e ⁻ (fuel side electrode)
(2) O ₂ + 2H ₂ O + 4e ⁻ → 4OH ⁻ (oxygen side electrode)
(3) NH ₂ NH ₂ + O ₂ → 2H ₂ O + N ₂ (whole)
The operating conditions of the fuel cell 1 are not particularly limited. For example, the pressure on the fuel side electrode 2 side is 100 kPa or less, preferably 50 kPa or less, and the pressure on the oxygen side electrode 3 side is 100 kPa or less. Preferably, it is 50 kPa or less, and the temperature of the fuel cell S is set to 30 to 100 ° C., preferably 60 to 90 ° C.

  In the fuel cell 1 described above, the metal precursor is reduced by supplying the liquid fuel, and the obtained metal simple substance is highly dispersed in the fuel side electrode 2. Therefore, according to the fuel cell 1 described above, excellent power generation performance can be obtained.

  Specifically, in the conventional manufacturing method of the fuel cell 1, a simple metal used as an electrode material is usually obtained by reducing and firing a metal precursor (metal salt or the like). Aggregation may reduce the specific surface area, which may cause a decrease in power generation performance.

In addition, the average particle diameter (measurement method: scanning electron microscope) of the aggregated metal simple substance is, for example, 200 nm or more, and the specific surface area (measurement method: BET method) is, for example, 10 m ² / g or less.

  On the other hand, in the manufacturing method of the fuel cell 1 described above, first, an electrode ink containing a metal precursor that becomes a metal simple substance by reduction is applied to the electrolyte layer 4 to form the fuel side electrode 2, and then such a fuel side A liquid fuel is supplied to the cell stack 15 including the electrode 2, and the metal precursor is reduced and made into a metal simple substance.

  That is, in such a manufacturing method of the fuel cell 1, a simple metal can be obtained without the reduction firing step.

  Therefore, since the fuel cell 1 obtained in this way is highly dispersed in the fuel-side electrode 2 without agglomeration of single metals, it can have excellent power generation performance.

  Specifically, the average particle size (primary particle size, measurement method: scanning electron microscope) of a single metal obtained by the above method is, for example, 10 nm or more, preferably 20 nm or more, for example, 50 nm or less. Preferably, it is 40 nm or less.

The specific surface area (measuring method: BET method) of the single metal is, for example, 100 m ² / g or more, preferably 200 m ² / g or more, for example, 400 m ² / g or less, preferably 300 m ² / g. It is as follows.

  Furthermore, in the manufacturing method of the fuel cell 1 described above, by supplying liquid fuel, it is possible to generate power in the cell stack 15 and reduce the metal precursor to obtain a single metal.

  Therefore, in the manufacturing method of the fuel cell 1 described above, when the fuel cell 1 is manufactured, a separate step of reducing and firing the metal precursor is unnecessary, and the fuel cell 1 can be obtained simply and at low cost.

  Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms.

  For example, in the above-described embodiment, a single metal is used as the electrode material of the fuel side electrode 2 and a metal precursor is blended in the fuel side electrode ink. For example, a single metal is used as the electrode material of the oxygen side electrode 3. A metal precursor can also be blended in the oxygen side electrode ink. Moreover, in both the fuel side electrode 2 and the oxygen side electrode 3, a metal simple substance can be used as an electrode material, and a metal precursor can be blended in both the fuel side electrode ink and the oxygen side electrode ink.

  In such a case, a metal precursor is contained in the oxygen-side electrode 3 after the cell formation step, but the metal precursor is reduced by the liquid fuel leaking to the oxygen-side electrode 3 side due to the crossover phenomenon. , It becomes a single metal.

  That is, in the power generation by the fuel cell 1, as described above, the liquid fuel is supplied to the fuel side electrode 2, but a part of the supplied liquid fuel does not react at the fuel side electrode 2, and the electrolyte The layer 4 may permeate through the osmotic pressure and leak to the oxygen side electrode 3 (crossover phenomenon).

  And the metal precursor contained in the oxygen side electrode 3 can be reduced by the liquid fuel leaked by this crossover phenomenon.

  Further, for example, in the above-described embodiment, the present invention has been described by exemplifying a solid polymer fuel cell. However, the present invention is, for example, an alkaline type using, for example, an aqueous KOH solution or an aqueous NaOH solution as the electrolyte layer 4, The present invention can also be applied to various fuel cells such as a molten carbonate type and a solid electrolyte type.

  Examples of the use of the fuel cell 1 include a power source for a driving motor in an automobile, a ship, and an aircraft, and a power source in a communication terminal such as a mobile phone.

  EXAMPLES Next, although this invention is demonstrated based on an Example, this invention is not limited by the following Example.

Example 1
<Preparation of fuel side electrode ink>
In an electronic balance, nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ .6H ₂ O, metal precursor) 14.86 g (3.0 g in terms of nickel), solvent 28.0 g (tetrahydrofuran 14.0 g and 1-propanol 14.0 g mixed solvent) and ionomer (Product No. A3, manufactured by Tokuyama Corporation) 16.632 g were weighed and mixed.

Next, the obtained mixed liquid was stirred for about 10 minutes by operating a homogenizer (manufactured by Taitec Corp., VP-050) at an output of about 35% to obtain a fuel-side electrode ink as a dispersion (slurry) ( (See FIG. 2 (a)).
<Preparation of oxygen side electrode ink>
In an electronic balance, 2.166 g of a metal complex catalyst (compound name: cobalt polypyrrole carbon, product number D8L001, manufactured by Hokuko Chemical Co., Ltd.), 36.0 g of solvent (a mixed solvent of 18.0 g of tetrahydrofuran and 18.0 g of 1-propanol), ionomer 36.207 g (product number A3, manufactured by Tokuyama Corporation) and 0.15 g of polytetrafluoroethylene (product number D-210C, manufactured by Daikin Industries, Ltd.) were weighed and mixed.

Subsequently, the obtained liquid mixture was stirred for about 3 minutes by operating a homogenizer (manufactured by Taitec Corp., VP-050) at an output of about 40% to obtain an oxygen-side electrode ink as a dispersion (slurry) ( (See FIG. 2 (a)).
<Fabrication of fuel cell>
Using a hand spray gun, the fuel-side electrode ink was sprayed on one side of the electrolyte layer (manufactured by Tokuyama), and the oxygen-side electrode ink was sprayed on the other side, and the amount of catalyst supported after drying (after solvent volatilization) 12.38mg / cm ² (metal precursors) in the fuel side electrode, an oxygen side electrode was uniformly applied so as to be 1.0 mg / cm ² (metal complex catalyst).

Then, it was made to dry at 25 degreeC for 30 minutes, and the oxygen side electrode was formed in the one side surface of the electrolyte layer, respectively, and the fuel side electrode was formed in the other side surface (refer FIG.2 (b)).
<Assembly>
Sixty fuel cells were stacked through a fuel supply member and an oxygen supply member to form a cell stack (see FIG. 3C).
<Particle removal>
Liquid fuel (20% hydrazine hydrate + 1MKOH) was supplied to the fuel electrode side of the cell stack for about 3 hours at a flow rate of 0.1 L / min per unit cell. On the other hand, an inert gas such as nitrogen was supplied to the oxygen side electrode side for about 3 hours at a flow rate of about 5 L / min per unit cell in order to discharge permeated fuel.

  As a result, nickel nitrate (metal precursor) in the fuel side electrode was reduced to form a single metal to obtain a fuel cell.

  When the fuel side electrode of the obtained fuel cell was observed by SEM (scanning electron microscope), nickel single metal was confirmed in the fuel side electrode.

Moreover, the average particle diameter (measuring method: scanning electron microscope) of the metal simple substance in a fuel side electrode was 30 nm, and the specific surface area (measuring method: BET method) was 100 m < ² > / g.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Fuel side electrode 3 Oxygen side electrode 4 Electrolyte layer 15 Cell laminated body S Fuel cell

Claims (1)

An ink preparation step for preparing an electrode ink containing a metal precursor that is converted into a metal by reduction;
A cell forming step of forming an electrode by applying the electrode ink to the electrolyte layer to obtain a fuel cell;
An assembly step of stacking a plurality of the fuel cells to obtain a cell stack, and
A method for producing a fuel cell, comprising: a reduction step of supplying a liquid fuel capable of reducing the metal precursor to the cell stack and reducing the metal precursor.

Images