WO2012105487A1 - Membrane electrode assembly and alkaline fuel cell using same - Google Patents

Abstract

Provided is a membrane electrode assembly for an alkaline fuel cell comprising an anion-conductive electrolyte membrane; a first electrode layered on a first surface of the anion-conductive electrolyte membrane; and a second electrode layered on a second surface opposite the first surface of the anion-conductive electrolyte membrane, wherein the membrane electrode assembly further comprises a third electrode layered on the first surface at a distance from the first electrode. Also provided are an alkaline fuel cell in which the membrane electrode assembly is used, and a method for using the alkaline fuel cell. The membrane electrode assembly can further comprise a fourth electrode layered on the second surface at a distance from the second electrode.

Description

Membrane electrode composite and alkaline fuel cell using the same

The present invention relates to a membrane electrode assembly, an alkaline fuel cell using the same, and a method for using the same.

Since fuel cells have the potential to achieve small size and light weight and high output density, the development of applications for new power sources for portable electronic devices and household cogeneration systems has been energetically promoted. Yes. The fuel cell includes a membrane electrode assembly (MEA) having a configuration in which an electrolyte membrane is sandwiched between an anode and a cathode as a main part of power generation. Depending on the type of electrolyte membrane, a polymer electrolyte fuel cell (direct fuel) Battery), phosphoric acid fuel cell, molten carbonate fuel cell, solid oxide fuel cell, alkaline fuel cell and the like.

An alkaline fuel cell is a fuel cell in which an anion conductive electrolyte membrane (anion exchange membrane) is used as an electrolyte membrane, and charge carriers are hydroxide ions (OH ⁻ ). In an alkaline fuel cell, when an anode electrode and a cathode electrode are electrically connected, a current flows between the anode electrode and the cathode electrode by the following electrochemical reaction, and electric energy can be obtained. That is, when an oxidizing agent (for example, oxygen or air) and water (this water may be water generated at the anode electrode and permeated through the electrolyte membrane) are supplied to the cathode electrode, the following formula (1):
Cathode electrode: 1 / 2O ₂ + H ₂ O + 2e ⁻ → 2OH ⁻ (1)
OH ⁻ is generated by the catalytic reaction represented by This OH ⁻ is transmitted to the anode side through the electrolyte membrane in a hydrated state with water molecules. On the other hand, in the anode electrode, the supplied reducing agent (fuel), for example, H ₂ gas and OH ⁻ transmitted from the cathode electrode are expressed by the following formula (2):
Anode electrode: H ₂ + 2OH ⁻ → 2H ₂ O + 2e ⁻ (2)
To generate water and electrons.

In an alkaline fuel cell, since an anion conductive electrolyte is used for the electrolyte of the electrolyte membrane and the catalyst layer, the electrolyte membrane and the catalyst layer absorb carbon dioxide (CO ₂ ) in the environment during operation stop, and the electrolyte membrane And OH ⁻ in the catalyst layer is replaced with CO ₃ ²⁻ and / or HCO ₃ ⁻ (hereinafter sometimes referred to as “CO ₂ -derived anion”) [see the following formulas (3) and (4)] . Such increase in the concentration of CO ₂ -derived anion (decrease in OH ⁻ ion concentration) decreases the anion conductivity of the electrolyte and greatly increases the cell resistance.

CO ₂ + 2OH ⁻ → CO ₃ ²⁻ + H ₂ O (3)
^{_{CO 2 + OH - → HCO 3}} - (4)
It is known that the problem of increasing the cell resistance can be improved by a phenomenon called self-purging caused by the operation of the fuel cell. Self-purging means that the CO ₂ -derived anion contained in the electrolyte membrane and the catalyst layer, which is a cause of a decrease in anion conductivity due to the operation of the fuel cell, moves to the anode electrode, is reduced by the reducing agent, and is anodeed as CO ₂ gas. This refers to a phenomenon that is discharged from the pole. Specifically, the following formulas (5) and (6):
H ₂ + CO ₃ ²⁻ → CO ₂ + H ₂ O + 2e ⁻ (5)
H ₂ + 2HCO ₃ ⁻ → 2CO ₂ + 2H ₂ O + 2e ⁻ (6)
Can be expressed as

However, as shown in Yu Matsui, Morihiro Saito, Akimasa Tasaka, and Minoru Inaba, ECS Transactions, 25 (13), 105-110 (2010) [Non-Patent Document 1], many CO ₂ Since the derived anion is re-substituted by OH ⁻ , it is possible to suppress an increase in cell resistance, but a certain amount of remaining CO ₂ -derived anion is localized and accumulated in the anode electrode by self-purge, There was a problem that the reaction overvoltage at the anode electrode was increased and the power generation efficiency was lowered.

The present invention has been made in view of the above problems, and its purpose is to reduce the reaction overvoltage at the anode electrode by suppressing the accumulation of CO ₂ -derived anions on the anode electrode due to self-purge, and thus good power generation. An object of the present invention is to provide a membrane electrode assembly for an alkaline fuel cell exhibiting efficiency and an alkaline fuel cell using the same.

The present invention provides an anion conductive electrolyte membrane, a first electrode laminated on a first surface of the anion conductive electrolyte membrane, and a second surface opposed to the first surface of the anion conductive electrolyte membrane. A membrane electrode assembly (MEA) comprising an alkaline fuel cell membrane electrode assembly including a second electrode, further comprising a third electrode spaced apart from the first electrode and laminated on the first surface. The first electrode and the second electrode are preferably provided so as to face each other with an anion conductive electrolyte membrane interposed therebetween.

The membrane electrode assembly of the present invention can include a plurality of third electrodes that are spaced apart from each other. In this case, it is preferable that the plurality of third electrodes be arranged substantially uniformly in the first surface.

The membrane electrode assembly of the present invention can further include a fourth electrode that is separated from the second electrode and stacked on the second surface, and further includes a plurality of fourth electrodes that are disposed apart from each other. Can do. In the case where a plurality of fourth electrodes are provided, it is preferable that these are arranged substantially uniformly in the second surface.

In one preferable embodiment including the fourth electrode, the first electrode and the second electrode are provided to face each other via the anion conductive electrolyte membrane, and the shortest path from the third electrode to the fourth electrode is A third electrode and a fourth electrode are provided so as to pass through the anion conductive electrolyte membrane interposed between the first electrode and the second electrode. In this embodiment, preferably, the third electrode is disposed on the outer side of the first electrode, and the fourth electrode is on the outer side of the second electrode opposite to the side facing the third electrode. Placed in.

The present invention also provides an alkaline fuel cell comprising at least the membrane electrode assembly and a current collecting layer laminated on each electrode, and a method for using the alkaline fuel cell. The first current collecting layer laminated on the first electrode and the third current collecting layer laminated on the third electrode are electrically insulated. Further, when the membrane electrode assembly includes the fourth electrode, the second current collecting layer laminated on the second electrode and the fourth current collecting layer laminated on the fourth electrode are electrically insulated.

As described above, the membrane electrode assembly of the present invention is independent of the electrodes responsible for substantial power generation (ie, the first electrode and the second electrode), and the third electrode used for self-purging and optionally A fourth electrode is provided. According to the alkaline fuel cell using such a membrane electrode composite, it is possible to suppress the accumulation of CO ₂ -derived anions on the electrode responsible for power generation, so that the electrode functioning as an anode electrode during power generation (first electrode) The reaction overvoltage in can be reduced, and the power generation efficiency can be improved.

It is a schematic sectional drawing which shows a preferable example of the membrane electrode assembly of this invention and an alkaline fuel cell using the same. FIG. 2 is a schematic sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line III-III shown in FIG. It is a schematic sectional drawing which shows another preferable example of the membrane electrode assembly of this invention, and an alkaline fuel cell using the same. FIG. 5 is a schematic cross-sectional view taken along line VV shown in FIG. 4. FIG. 5 is a schematic sectional view taken along line VI-VI shown in FIG. 4. It is a schematic sectional drawing which shows another preferable example of the membrane electrode assembly of this invention, and an alkaline fuel cell using the same. FIG. 8 is a schematic sectional view taken along line VIII-VIII shown in FIG. FIG. 8 is a schematic sectional view taken along line IX-IX shown in FIG. 7. It is a schematic sectional drawing which shows another preferable example of the membrane electrode assembly of this invention, and an alkaline fuel cell using the same. It is a schematic sectional drawing in the XI-XI line shown by FIG. It is a schematic sectional drawing in the XII-XII line | wire shown by FIG. It is a schematic sectional drawing which shows another preferable example of the membrane electrode assembly of this invention, and an alkaline fuel cell using the same. It is a schematic sectional drawing in the XIV-XIV line | wire shown by FIG. It is a schematic sectional drawing in the XV-XV line | wire shown by FIG. FIG. 14 is a schematic sectional view taken along line XVI-XVI shown in FIG. 13. FIG. 14 is a schematic sectional view taken along line XVII-XVII shown in FIG. 13. 1 is a schematic cross-sectional view showing an alkaline fuel cell produced in Example 1. FIG. It is a schematic sectional drawing in the XIX-XIX line | wire shown by FIG. FIG. 19 is a schematic sectional view taken along line XX-XX shown in FIG. 3 is a schematic cross-sectional view showing an alkaline fuel cell produced in Example 2. FIG. FIG. 22 is a schematic sectional view taken along line XXII-XXII shown in FIG. 21. FIG. 22 is a schematic sectional view taken along line XXIII-XXIII shown in FIG. 21. 6 is a schematic cross-sectional view showing an alkaline fuel cell produced in Example 3. FIG. FIG. 25 is a schematic sectional view taken along line XXV-XXV shown in FIG. 24. FIG. 25 is a schematic sectional view taken along line XXVI-XXVI shown in FIG. 24. FIG. 25 is a schematic sectional view taken along line XXVII-XXVII shown in FIG. 24. FIG. 25 is a schematic sectional view taken along line XXVIII-XXVIII shown in FIG. 24.

The membrane electrode assembly of the present invention is characterized by including a third electrode for self-purging separately from the electrodes (first electrode and second electrode) responsible for substantial power generation. The third electrode is laminated on the surface of the anion conductive electrolyte membrane (first surface) on the same side as the first electrode that functions as the anode electrode during power generation, but is separated from (not in contact with) the first electrode. ) Arranged. Moreover, the membrane electrode assembly of the present invention can also include a fourth electrode for self-purging in addition to the third electrode. The fourth electrode is laminated on the surface of the anion conductive electrolyte membrane (second surface) on the same side as the second electrode that functions as a cathode electrode during power generation, but is separated from (not in contact with) the second electrode. ) Arranged. An alkaline fuel cell including such a membrane electrode assembly performs substantial power generation using the first and second electrodes after self-purging using the third and fourth electrodes.

According to the alkaline fuel cell using such a membrane electrode composite, the CO ₂ -derived anion concentration of the first electrode, the second electrode and the anion conductive electrolyte membrane can be reduced (increase the OH ⁻ concentration) by self-purge. As a result, an increase in cell resistance can be suppressed, and the accumulation of CO ₂ -derived anions due to self-purging mainly occurs in the third electrode and / or the fourth electrode, so that the first electrode functions as an anode electrode during power generation. The reaction overvoltage in can be reduced, and the power generation efficiency can be improved.

In addition, ion current flows through the membrane electrode assembly due to self-purging, and this causes the membrane electrode assembly to be in an appropriately warmed state. A sufficiently high power can be obtained from the beginning.

Hereinafter, a membrane electrode assembly of the present invention, an alkaline fuel cell using the same, and a method for using the same will be described in detail with reference to embodiments.

<First Embodiment>
(1) Configuration of Membrane Electrode Assembly and Alkaline Fuel Cell FIG. 1 is a schematic cross-sectional view showing a membrane electrode assembly according to the present embodiment and an alkaline fuel cell using the same, and FIGS. FIG. 3 is a schematic cross-sectional view taken along lines II-II and III-III shown in FIG. 1, respectively. The alkaline fuel cell 100 of this embodiment is characterized by including a membrane electrode assembly (MEA) 10. The membrane electrode assembly 10 includes an anion conductive electrolyte membrane 101; a first electrode 103 laminated on the first surface of the anion conductive electrolyte membrane 101; and a second surface opposite to the first surface of the anion conductive electrolyte membrane 101. It is mainly composed of a second electrode 102 to be laminated; and a third electrode 110 for self-purging that is separated from the first electrode 103 and laminated on the first surface. A gasket 106 (for example, a layer made of an elastic resin such as silicone rubber or a cured resin layer of a curable resin such as an epoxy resin) is provided at the periphery of the electrode to prevent intrusion of air or the like from the electrode end face. Is provided.

The first electrode 103 and the second electrode 102 are provided to face each other with the anion conductive electrolyte membrane 101 interposed therebetween. In the present embodiment, the first electrode 103 is divided into two layers and the third electrode 110 is disposed between the two first electrodes 103 so as to be separated from the first electrode 103. ing.

The alkaline fuel cell 100 includes a first current collecting layer 105 laminated on the first electrode 103; a second current collecting layer 104 laminated on the second electrode 102; and a layer laminated on the third electrode 110. The third current collecting layer 120 is provided. These current collecting layers are members for exchanging electrons with an electrode in contact with the current collecting layer and for performing electrical wiring. The first current collecting layer 105 and the third current collecting layer 120 are electrically insulated from each other by interposing an insulating layer 130 between these current collecting layers. The first current collecting layer 105 and the third current collecting layer 120 are provided with a first flow path 105 a for supplying a reducing agent to the first electrode 103 or the third electrode 110. Similarly, the second current collection layer 104 is provided with a second flow path 104 a for supplying an oxidant to the second electrode 102. Thus, in this embodiment, each current collection layer is also a member for supplying a reducing agent and an oxidizing agent.

Furthermore, the alkaline fuel cell 100 includes an external wiring 145 and switching means (switch) 140 interposed in the external wiring 145. The switching means 140 is for switching the connection relationship between the current collecting layers. The current collecting layer electrically connected to the second current collecting layer 104 is connected to the first current collecting layer 105 or the third current collecting layer 120. You can switch to either.

(Anion conductive electrolyte membrane)
As the anion conductive electrolyte membrane 101, in particular, as long as it can conduct OH ⁻ ions and has electrical insulation to prevent a short circuit between the first electrode 103 and the third electrode 110 and the second electrode 102, Although not limited, an anion conductive solid polymer electrolyte membrane can be suitably used. Preferable examples of the anion conductive solid polymer electrolyte membrane include, for example, perfluorosulfonic acid type, perfluorocarboxylic acid type, styrene vinyl benzene type, quaternary ammonium type solid polymer electrolyte membrane (anion exchange membrane). It is done. A membrane obtained by impregnating polyacrylic acid with a concentrated potassium hydroxide solution or an anion conductive solid oxide electrolyte membrane can also be used as the anion conductive electrolyte membrane 101.

The anion conductive electrolyte membrane 101 preferably has an anion conductivity of 10 ⁻⁵ S / cm or more, and an electrolyte membrane having an anion conductivity of 10 ⁻³ S / cm or more such as a perfluorosulfonic acid polymer electrolyte membrane. It is more preferable to use The thickness of the anion conductive electrolyte membrane 101 is usually 5 to 300 μm, preferably 10 to 200 μm.

(First electrode and second electrode)
A first electrode 103 that is stacked on the first surface of the anion conductive electrolyte membrane 101 and functions as an anode electrode during power generation, and a second electrode that is stacked on a second surface facing the first surface and functions as a cathode electrode during power generation. The electrode 102 is provided with at least a catalyst layer composed of a porous layer containing a catalyst and an electrolyte. These catalyst layers are laminated in contact with the surface of the anion conductive electrolyte membrane 101. The catalyst (anode catalyst) of the first electrode 103 catalyzes a reaction that generates water and electrons from the reducing agent and OH ⁻ supplied to the first electrode 103. The electrolyte of the first electrode 103 has a function of conducting OH ⁻ conducted from the anion conductive electrolyte membrane 101 to the catalytic reaction site. On the other hand, the catalyst (cathode catalyst) of the second electrode 102 catalyzes the reaction of generating OH ⁻ from the oxidant and water supplied to the second electrode 102 and the electrons transferred from the first electrode 103. The electrolyte of the second electrode 102 has a function of conducting the generated OH ⁻ to the anion conductive electrolyte membrane 201.

As the anode catalyst and the cathode catalyst, conventionally known ones can be used. For example, platinum, iron, cobalt, nickel, palladium, silver, ruthenium, iridium, molybdenum, manganese, these metal compounds, and these metals And fine particles made of an alloy containing two or more of the above. The alloy is preferably an alloy containing at least two of platinum, iron, cobalt, and nickel. For example, platinum-iron alloy, platinum-cobalt alloy, iron-cobalt alloy, cobalt-nickel alloy, iron-nickel alloy, etc. And iron-cobalt-nickel alloys. The anode catalyst and the cathode catalyst may be the same or different.

The anode catalyst and the cathode catalyst are preferably those supported on a carrier, preferably a conductive carrier. Examples of the conductive carrier include carbon black such as acetylene black, furnace black, channel black, and ketjen black, and conductive carbon particles such as graphite and activated carbon. In addition, carbon fibers such as vapor grown carbon fiber (VGCF), carbon nanotube, carbon nanowire, and the like can be used.

As the electrolyte of the first electrode 103 and the second electrode 102, the same electrolyte as that constituting the anion conductive solid polymer electrolyte membrane can be used. The content ratio of the catalyst to the electrolyte in each catalyst layer is usually 5/1 to 1/4, and preferably 3/1 to 1/3, based on weight.

The first electrode 103 and the second electrode 102 may each include a gas diffusion layer laminated on the catalyst layer. The gas diffusion layer has a function of diffusing the supplied reducing agent or oxidizing agent in the surface and also has a function of transferring electrons to and from the catalyst layer.

The gas diffusion layer can be a porous layer having electrical conductivity. Specifically, for example, carbon paper; carbon cloth; epoxy resin film containing carbon particles; metal or alloy foam, sintered body Or it can be a fiber nonwoven fabric. The thickness of the gas diffusion layer is preferably 10 μm or more in order to reduce the diffusion resistance of the reducing agent or oxidizing agent in the direction perpendicular to the thickness direction (in-plane direction), and the diffusion resistance in the thickness direction. In order to reduce this, it is preferable that it is 1 mm or less. The thickness of the gas diffusion layer is more preferably 100 to 500 μm.

As shown in FIG. 1, the first electrode 103 and the second electrode 102 are preferably provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween. Such an opposing arrangement makes the distance between the first electrode 103 and the second electrode 102 the shortest, thereby reducing the resistance when a current flows between these electrodes, thus reducing the power generation efficiency. Can be suppressed.

The first electrode 103 and the second electrode 102 are preferably formed with the largest possible area on the anion conductive electrolyte membrane 101 from the viewpoint of improving the output per unit area of the fuel cell. As shown, the anion conductive electrolyte membrane 101 is preferably formed to have the same length or the same length.

(Third electrode)
The third electrode 110 is an electrode for Serufupaji is an electrode for discharging CO ₂ from anionic as CO ₂ gas by the supply of the reducing agent. Regarding the configuration and composition of the third electrode 110, the contents described above for the first electrode 103 are cited.

The third electrode 110 is disposed on the first surface of the anion conductive electrolyte membrane 101 so as to be separated from the first electrode 103 in order to function independently for self-purging. Here, in the membrane electrode assembly 10 shown in FIG. 1 and FIG. 2, the first electrode 103 is divided into two, and a central region of the first surface of the anion conductive electrolyte membrane 101 between them. Although the 3rd electrode 110 is arrange | positioned in this, it is not limited to such an arrangement | positioning. For example, the number of the first electrodes 103 (whether or not divided) and the positions of the third electrodes 110 are particularly limited, such as arranging the third electrodes 110 on the side of the first electrodes 103 without dividing the first electrodes 103. Not. However, in consideration of self-purge efficiency, it is preferable to provide the third electrode 110 at a position facing the second electrode 102.

The ratio between the area (width × length) of the first electrode 103 and the area of the third electrode 110 is determined in consideration of both the power generation capability of the fuel cell and the self-purge efficiency. If the ratio (the area of the first electrode 103 / the area of the third electrode 110) is too large, the third electrode 110 is too small and the self-purging efficiency is lowered. On the other hand, if the ratio is too small, the first electrode 103 serving as the anode electrode that contributes to power generation is too small to obtain a sufficient output. Considering the efficiency of self-purge, the length of the third electrode 110 is preferably long so that CO ₂ -derived anions can be taken from as wide a range as possible of the anion conductive electrolyte membrane 101. For example, the anion conductive electrolyte membrane 101 Can be the same or substantially the same length (see FIG. 2). The thickness of the first electrode 103 and the thickness of the third electrode 110 are preferably the same.

(Collector layer)
The first current collecting layer 105, the second current collecting layer 104, and the third current collecting layer 120 are provided on and in contact with the first electrode 103, the second electrode 102, and the third electrode 110, respectively. It is a member for transferring electrons and performing electrical wiring. Further, in the alkaline fuel cell 100 of the present embodiment, these current collecting layers also have a function of supplying a reducing agent and an oxidizing agent, and the first current collecting layer 105 and the third current collecting layer 120 include A first flow path 105 a for supplying a reducing agent to the first electrode 103 and the third electrode 110 is provided in the second current collecting layer 104, and a second flow path 104 a for supplying an oxidant to the second electrode 102. Is provided.

As described above, the first current collecting layer 105 and the third current collecting layer 120 are electrically insulated from each other by interposing the insulating layer 130 between these current collecting layers. The insulating layer 130 is not particularly limited as long as it exhibits electrical insulation, and can be made of, for example, various nonconductive polymers (including insulating adhesives). The material of the current collecting layer is not particularly limited, and for example, a conductive material such as a carbon material, a conductive polymer, various metals, and an alloy typified by stainless steel can be used. The material of each current collecting layer may be the same or different.

The first flow path 105a and the second flow path 104a can be composed of one or more grooves provided on the electrode-side surface of the current collecting layer, and the shape thereof is not particularly limited, and is linear or serpentine Etc. The flow path for supplying the reducing agent to the first electrode 103 and the flow path for supplying the reducing agent to the third electrode 110 may or may not be connected.

Instead of providing the current collecting layer with a function of supplying a reducing agent and an oxidizing agent, a separate member (channel plate) for supplying the reducing agent and the oxidizing agent may be laminated on the current collecting layer. For example, the flow path plate may be one in which one or more grooves are provided on the surface of a plate-like body made of a non-conductive material such as various plastic materials.

According to the alkaline fuel cell having the above-described configuration, for example, the desired effect described above can be obtained by operating according to the following method.

(2) Usage Method of Alkaline Fuel Cell First, an oxidant is supplied to the second electrode 102 through the second flow path 104a of the second current collection layer 104 and through the first flow path 105a of the third current collection layer 120. The reducing agent is supplied to the third electrode 110, and further, the switching means 140 (connects the terminals A1 and A2 shown in FIG. 1), the second current collecting layer 104 and the third current collecting layer 120 (therefore, the second current collecting layer 120). The electrode 102 and the third electrode 110) are electrically connected, and a current (ion current) is allowed to flow between the second electrode 102 and the third electrode 110 for a certain time [self-purging step]. By this step, a catalytic reaction like the above formula (1) occurs in the second electrode 102, while a self purge reaction like the above formulas (5) and (6) occurs in the third electrode 110 (partly, Catalytic reaction like the above formula (2) may also occur). By these reactions, the anion conductive electrolyte membrane 101 and the CO ₂ -derived anion mainly contained in the second electrode 102 among the electrodes move to the third electrode 110 and are reduced by the reducing agent as CO ₂ gas. It is discharged from the third electrode 110.

Here, the above-mentioned “certain time” may be a time until the completion of self-purge, and is specifically 2 to 60 minutes, preferably about 5 to 20 minutes. The time until the completion of the self-purging is the time from the start of the self-purging step to the decrease and stabilization after the discharge amount of the CO ₂ -derived anion increases once. Completion of self-purging is observed with respect to the time variation of the ohmic resistance of the membrane electrode assembly, the time variation of the current when the self-purging step is a constant potential operation, and the time variation of the voltage when the self-purging step is a constant current operation. Can be determined. If the time fluctuation of the observed value becomes a certain value or less, the self-purge may be regarded as completed.

Since many CO ₂ -derived anions are replaced again with OH ⁻ by the self-purge, an increase in cell resistance can be suppressed. In addition, since accumulation of CO ₂ -derived anions due to self-purging mainly occurs at the third electrode 110, the reaction overvoltage at the first electrode 103 functioning as the anode electrode during power generation can be reduced, and therefore, good power generation efficiency is achieved. Can be demonstrated. In addition, since the 1st current collection layer 105 and the 3rd current collection layer 120 are electrically insulated, the 1st electrode 103 does not participate in a self purge.

As the reducing agent, for example, H ₂ gas, hydrocarbon gas, ammonia gas, or the like can be used. Among these, it is preferable to use H ₂ gas. As the oxidizing agent, for example, O ₂ gas or a gas containing O ₂ such as air can be used. Of these, air is preferably used.

In addition, it is also possible to implement a self purge process, without supplying a reducing agent to the 3rd electrode 110 (same also about other embodiment mentioned later). That is, an external power supply (power generation device) is interposed in the external wiring 145, the external power supply is operated, and a current is forcibly passed between the second electrode 102 and the third electrode 110, whereby CO _2. The derived anion can be moved to the third electrode 110, reduced by the electric energy of the external power source, and discharged from the third electrode 110 as CO ₂ gas. Reduction of the CO ₂ -derived anion by the electric energy of the external power source is represented by the following formulas (7) and (8):
CO ₃ ²⁻ → CO ₂ + 1 / 2O ₂ + 2e ⁻ (7)
2HCO ₃ ⁻ → 2CO ₂ + 1 / 2O ₂ + H ₂ O + 2e ⁻ (8)
Follow the reaction as

The external power source can also be used when self-purging is performed while supplying a reducing agent to the third electrode 110, thereby shortening the time required for the self-purging process.

After the self-purging step, the electrical connection between the second electrode 102 and the third electrode 110 is cut, and then the reducing agent is supplied to the first electrode 103 through the first flow path 105a of the first current collecting layer 105. Then, an oxidant is supplied to the second electrode 102 through the second flow path 104a of the second current collecting layer 104, and the first current collecting is performed by the switching means 140 (connecting the terminals A1 and A3 shown in FIG. 1). Electric power is obtained by electrically connecting the layer 105 and the second current collecting layer 104 (therefore, the first electrode 103 and the second electrode 102) [power generation step]. As described above, since the accumulation of CO ₂ -derived anions does not easily occur in the first electrode 103 even by self-purge, good power generation efficiency can be exhibited.

<Second Embodiment>
FIG. 4 is a schematic cross-sectional view showing a membrane electrode assembly and an alkaline fuel cell using the same according to the present embodiment. FIGS. 5 and 6 are respectively a VV line and a VI-line shown in FIG. It is a schematic sectional drawing in VI line. As shown in FIGS. 4 and 5, the alkaline fuel cell 200 of the present embodiment includes a membrane electrode assembly 20 having a plurality of self-purge third electrodes 110 (three in the example of FIG. 4). The other features are the same as those in the first embodiment (possible modifications are also the same as those in the first embodiment). Also, the method of using the alkaline fuel cell is the same as in the first embodiment.

The membrane electrode assembly 20 includes an anion conductive electrolyte membrane 101; a first electrode 103 stacked on the first surface of the anion conductive electrolyte membrane 101; a second electrode stacked on the second surface of the anion conductive electrolyte membrane 101. 102; and three third electrodes 110 that are separated from the first electrode 103 and stacked on the first surface. As in the first embodiment, a gasket 106 is provided on the periphery of the electrode. The first electrode 103 and the second electrode 102 are provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween.

In the present embodiment, the first electrode 103 is divided into two and laminated, and the first electrode 103 and the two first electrodes 103 and the outer sides of the two first electrodes 103 are respectively A total of three third electrodes 110 are arranged so as to be separated from each other.

The alkaline fuel cell 200 includes a first current collecting layer 105 (two in total) laminated on the first electrode 103; a second current collecting layer 104 laminated on the second electrode 102; and a third electrode 110. A third current collecting layer 120 (three in total) is provided thereon. The first current collecting layer 105 and the third current collecting layer 120 are electrically insulated from each other by interposing an insulating layer 130 between these current collecting layers. The first current collecting layer 105 and the third current collecting layer 120 are provided with a first flow path 105a for supplying a reducing agent to the first electrode 103 or the third electrode 110, and the second current collecting layer 105a. The layer 104 is provided with a second flow path 104 a for supplying an oxidant to the second electrode 102.

The alkaline fuel cell 200 includes an external wiring 145 and switching means (switch) 140 interposed in the external wiring 145. The switching means 140 can switch the current collecting layer electrically connected to the second current collecting layer 104 to either the first current collecting layer 105 or the third current collecting layer 120.

In the case where a plurality of third electrodes 110 are provided as in the present embodiment, as shown in FIGS. 4 and 5, the plurality of third electrodes 110 are substantially disposed within the first surface of the anion conductive electrolyte membrane 101. It is preferable to disperse them evenly. This is due to the following reason. Since the anion conductive electrolyte membrane 101 is very thin, the ion conduction resistance in the film thickness direction is very small compared to the ion conduction resistance in the in-plane direction. Therefore, when the self-purge is advanced, the movement of the CO ₂ -derived anion occurs mainly between the anion conductive electrolyte membrane 101 in the vicinity of the third electrode 110 and the second electrode 102 and the third electrode 110, and the self-purge is preferential. Proceed to. On the other hand, since the ion conduction resistance is large between the anion conductive electrolyte membrane 101 and the second electrode 102 and the third electrode 110 in a region far from the third electrode 110, the movement of the CO ₂ -derived anion hardly occurs, There is a tendency that self-purge does not progress sufficiently. By providing a plurality of third electrodes 110, and preferably disposing them in a substantially uniform manner in the first surface, the area in the vicinity of the third electrode 110 can be increased, whereby an anion conducting electrolyte membrane is obtained. The self-purge of the entire 101 and the second electrode 102 can be performed. In consideration of the efficiency of self-purge, the plurality of third electrodes 110 are preferably provided at positions facing the second electrodes 102.

<Third Embodiment>
(1) Configuration of Membrane Electrode Assembly and Alkaline Fuel Cell FIG. 7 is a schematic cross-sectional view showing a membrane electrode assembly according to the present embodiment and an alkaline fuel cell using the same, and FIGS. FIG. 8 is a schematic cross-sectional view taken along lines VIII-VIII and IX-IX shown in FIG. 7, respectively (the cross-sectional structure on the anode electrode side is the same as in FIGS. 2 and 3). As shown in FIGS. 7 and 8, the alkaline fuel cell 300 of the present embodiment includes the membrane electrode assembly 30 having the fourth electrode 115 for self-purging in addition to the third electrode 110 for self-purging. Other configurations can be the same as those of the first embodiment (possible modifications are also the same as those of the first embodiment).

The membrane electrode assembly 30 includes an anion conductive electrolyte membrane 101; a first electrode 103 laminated on the first surface of the anion conductive electrolyte membrane 101; a second electrode laminated on the second surface of the anion conductive electrolyte membrane 101. 102; a third electrode 110 stacked on the first surface spaced apart from the first electrode 103; and a fourth electrode 115 stacked on the second surface spaced apart from the second electrode 102. As in the first embodiment, a gasket 106 is provided on the periphery of the electrode. The first electrode 103 and the second electrode 102 are provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween. The third electrode 110 and the fourth electrode 115 are provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween.

In the present embodiment, the first electrode 103 is divided into two layers and the third electrode 110 is disposed between the two first electrodes 103 so as to be separated from the first electrode 103. . Similarly, the second electrode 102 is divided into two layers and a fourth electrode 115 is disposed between the two second electrodes 102 so as to be separated from the second electrode 102.

The alkaline fuel cell 300 includes a first current collecting layer 105 laminated on the first electrode 103; a second current collecting layer 104 laminated on the second electrode 102; a third laminated on the third electrode 110. Current collecting layer 120; and a fourth current collecting layer 125 stacked on the fourth electrode 115. The first current collecting layer 105 and the third current collecting layer 120 are electrically insulated from each other by interposing an insulating layer 130 between these current collecting layers. Similarly, the second current collecting layer 104 and the fourth current collecting layer 125 are electrically insulated from each other with the insulating layer 130 interposed therebetween. Further, the first current collecting layer 105 and the third current collecting layer 120 are provided with a first flow path 105 a for supplying a reducing agent or an oxidizing agent to the first electrode 103 or the third electrode 110. Similarly, the second current collecting layer 104 and the fourth current collecting layer 125 are provided with a second flow path 104 a for supplying a reducing agent or an oxidizing agent to the second electrode 102 or the fourth electrode 115.

The alkaline fuel cell 300 includes an external wiring 145 and switching means (switch) 140 interposed in the external wiring 145. The switching means 140 can switch the current collecting layer to be connected.

The fourth electrode 115, like the third electrode 110 is an electrode for Serufupaji is an electrode for discharging CO ₂ from anionic as CO ₂ gas by the supply of the reducing agent. Regarding the configuration and composition of the fourth electrode 115, the contents already described for the first electrode 103 are cited.

In addition to the third electrode 110, the provision of the fourth electrode 115 is advantageous in the following points. That is, in the case of a membrane electrode assembly including only the third electrode 110 as a self-purge electrode, as shown in the first embodiment, the anion conductive electrolyte membrane 101 and the second electrode mainly among the electrodes are mainly used. While the self-purge of the first electrode 103 can be performed, the self-purge of the first electrode 103 cannot be effectively performed. On the other hand, when the fourth electrode 115 is provided on the second surface, an oxidizing agent is supplied to the first electrode 103, a reducing agent is supplied to the fourth electrode 115, and the first electrode 103 and the fourth electrode 115 are When a current is passed between the first electrode 103 and the first electrode 103, the self-purge of the first electrode 103 can be effectively performed. Specifically, the usage method of the alkaline fuel cell of this embodiment is as follows.

(2) Usage Method of Alkaline Fuel Cell First, an oxidant is supplied to the first electrode 103 through the first flow path 105a of the first current collection layer 105, and through the second flow path 104a of the fourth current collection layer 125. The reducing agent is supplied to the fourth electrode 115, and further, the switching unit 140 (connects the terminals B3 and B4 shown in FIG. 7), the first current collecting layer 105 and the fourth current collecting layer 125 (therefore, the first current collecting layer 125). The electrode 103 and the fourth electrode 115) are electrically connected, and a current (ion current) is allowed to flow between the first electrode 103 and the fourth electrode 115 for a certain time [first self-purging step]. By this step, a catalytic reaction as expressed by the above formula (1) occurs in the first electrode 103, while a self purge reaction as expressed in the above formulas (5) and (6) occurs at the fourth electrode 115 (partly, Catalytic reaction like the above formula (2) may also occur). By these reactions, the CO ₂ -derived anion contained in the anion conductive electrolyte membrane 101 and the first electrode 103 moves to the fourth electrode 115, is reduced by the reducing agent, and is discharged from the fourth electrode 115 as CO ₂ gas. It will be. In the first self-purging step, the first electrode 103 functions as a cathode electrode.

Next, after disconnecting the electrical connection between the first electrode 103 and the fourth electrode 115, an oxidant is supplied to the second electrode 102 through the second flow path 104 a of the second current collecting layer 104, and the first The reducing agent is supplied to the third electrode 110 through the first flow path 105a of the third current collecting layer 120, and the second current collecting layer 104 is further connected by the switching means 140 (connecting the terminals B1 and B2 shown in FIG. 7). And the third current collecting layer 120 (therefore, the second electrode 102 and the third electrode 110) are electrically connected, and a current (ion current) is supplied between the second electrode 102 and the third electrode 110 for a certain period of time. [Second self-purging step]. By this step, a catalytic reaction like the above formula (1) occurs in the second electrode 102, while a self purge reaction like the above formulas (5) and (6) occurs in the third electrode 110 (partly, Catalytic reaction like the above formula (2) may also occur). By these reactions, the CO ₂ -derived anion contained in the anion conductive electrolyte membrane 101 and the second electrode 102 moves to the third electrode 110, is reduced by the reducing agent, and is discharged from the third electrode 110 as CO ₂ gas. It will be. In the second self-purging step, the second electrode 102 functions as a cathode electrode.

As described above, by performing the first and second self-purging steps, all the self-purging of the anion conductive electrolyte membrane 101, the first electrode 103, and the second electrode 102 can be performed. As a result, an increase in cell resistance can be suppressed more effectively, and a reaction overvoltage in the first electrode 103 that functions as an anode electrode during power generation can be reduced more effectively. Power generation efficiency can be demonstrated.

After the second self-purging step, the electrical connection between the second electrode 102 and the third electrode 110 is cut, and then the reducing agent is supplied to the first electrode 103 through the first flow path 105a of the first current collecting layer 105. At the same time, an oxidant is supplied to the second electrode 102 through the second flow path 104a of the second current collecting layer 104, and is further switched by the switching means 140 (connecting the terminals B1 and B4 shown in FIG. 7). Electric power is obtained by electrically connecting the current collecting layer 105 and the second current collecting layer 104 (therefore, the first electrode 103 and the second electrode 102) [power generation step]. As described above, since the accumulation of CO ₂ -derived anions does not easily occur in the first electrode 103 even by self-purge, good power generation efficiency can be exhibited.

Needless to say, the same effect can be obtained even if the order of the first self-purging step and the second self-purging step is reversed.

<Fourth Embodiment>
FIG. 10 is a schematic cross-sectional view showing a membrane electrode assembly according to the present embodiment and an alkaline fuel cell using the same, and FIGS. 11 and 12 are XI-XI line and XII-line shown in FIG. 10, respectively. It is a schematic sectional drawing in the XII line (The cross-sectional structure of the anode pole side is the same as that of FIG. 5 and FIG. 6). As shown in FIGS. 10 and 11, the alkaline fuel cell 400 of the present embodiment includes the membrane electrode assembly 40 having a plurality of self-purge fourth electrodes 115 (three in the example of FIG. 10). The other features are the same as those in the third embodiment (possible modifications are also the same as those in the third embodiment). The method of using the alkaline fuel cell is the same as in the third embodiment. The alkaline fuel cell 400 has a plurality of (three in the example of FIG. 10) third electrodes 110, and this is the same as in the second embodiment.

The membrane electrode assembly 40 includes an anion conductive electrolyte membrane 101; a first electrode 103 laminated on the first surface of the anion conductive electrolyte membrane 101; a second electrode laminated on the second surface of the anion conductive electrolyte membrane 101. 102; three third electrodes 110 stacked on the first surface spaced apart from the first electrode 103; and three fourth electrodes 115 stacked on the second surface spaced apart from the second electrode 102 Mainly composed. As in the first embodiment, a gasket 106 is provided on the periphery of the electrode. The first electrode 103 and the second electrode 102 are provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween. The third electrode 110 and the fourth electrode 115 are provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween.

In the present embodiment, the first electrode 103 is divided into two and laminated, and the first electrode 103 and the two first electrodes 103 and the outer sides of the two first electrodes 103 are respectively A total of three third electrodes 110 are arranged so as to be separated from each other. Similarly, the second electrode 102 is divided into two and laminated, and is separated from the second electrode 102 between the two second electrodes 102 and on the outer side of each of the two second electrodes 102. Thus, a total of four fourth electrodes 115 are arranged.

The alkaline fuel cell 400 includes a first current collecting layer 105 (two in total) laminated on the first electrode 103; a second current collecting layer 104 (two in total) laminated on the second electrode 102; A third current collecting layer 120 (three in total) laminated on the three electrodes 110; and a fourth current collecting layer 125 (three in total) laminated on the fourth electrode 115. The first current collecting layer 105 and the third current collecting layer 120 are electrically insulated from each other by interposing an insulating layer 130 between these current collecting layers. Similarly, the second current collecting layer 104 and the fourth current collecting layer 125 are electrically insulated from each other with the insulating layer 130 interposed therebetween. Further, the first current collecting layer 105 and the third current collecting layer 120 are provided with a first flow path 105 a for supplying a reducing agent or an oxidizing agent to the first electrode 103 or the third electrode 110. Similarly, the second current collecting layer 104 and the fourth current collecting layer 125 are provided with a second flow path 104 a for supplying a reducing agent or an oxidizing agent to the second electrode 102 or the fourth electrode 115.

Alkaline fuel cell 400 includes external wiring 145 and switching means (switch) 140 interposed in external wiring 145. The switching means 140 can switch the current collecting layer to be connected.

In the case where a plurality of fourth electrodes 115 are provided as in the present embodiment, for the same reason as in the case of the third electrode 110, as shown in FIGS. It is preferable that the conductive electrolyte membrane 101 is disposed so as to be substantially evenly dispersed in the second surface of the conductive electrolyte membrane 101. By providing a plurality of fourth electrodes 115, and preferably disposing them in a substantially uniform manner in the second surface, the area in the vicinity of the fourth electrode 115 can be increased, whereby an anion conductive electrolyte membrane is obtained. 101 and the entire first electrode 103 can be self-purged.

Preferably, as shown in FIG. 10, a plurality of third electrodes 110 and a plurality of fourth electrodes 115 are provided, and these are arranged so as to be distributed substantially evenly on the first surface and the second surface, respectively. As a result, the entire anion conductive electrolyte membrane 101, the first electrode 103, and the second electrode 102 can be self purged.

<Fifth Embodiment>
(1) Configuration of Membrane Electrode Assembly and Alkaline Fuel Cell FIG. 13 is a schematic cross-sectional view showing a membrane electrode assembly according to the present embodiment and an alkaline fuel cell using the membrane electrode assembly, and FIGS. FIG. 14 is a schematic cross-sectional view taken along lines XIV-XIV, XV-XV, XVI-XVI, and XVII-XVII shown in FIG. 13, respectively. The alkaline fuel cell 500 of the present embodiment is the same as the third embodiment in that it includes the third electrode 110 and the fourth electrode 115 for self-purging, but the third electrode 110 and the fourth electrode 115 are different from each other. It has a feature in arrangement relation. That is, in the membrane electrode assembly 50 included in the alkaline fuel cell 500, the third electrode 110 and the fourth electrode 115 are not provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween. The fourth electrode 115 is arranged on the outer side opposite to the side facing the third electrode 110 in the second electrode 102 with respect to the third electrode 110 arranged on one outer side of 103. . The configuration other than the arrangement relationship between the third electrode 110 and the fourth electrode 115 is the same as that of the third embodiment (possible modifications are also the same as those of the third embodiment). The first electrode 103 and the second electrode 102 are provided so as to face each other with the anion conductive electrolyte membrane 101 interposed therebetween.

On the other hand, regarding the functions of the third electrode 110 and the fourth electrode 115, in the third and fourth embodiments, the third electrode 110 and the fourth electrode 115 are both CO ₂ by supplying a reducing agent in the self-purging process. In the present embodiment, either the third electrode 110 or the fourth electrode 115 is an oxidizing agent in the self-purging process, while discharging the derived anions as CO ₂ gas and accumulating the remaining CO ₂ -derived anions. It plays a role as a cathode electrode to which is supplied.

According to the present embodiment, it is advantageous to arrange the third electrode 110 and the fourth electrode 115 in the arrangement relationship as shown in FIG.

(A) For example, when a reducing agent is supplied to the third electrode 110, an oxidizing agent is supplied to the fourth electrode 115, and the third electrode 110 and the fourth electrode 115 are electrically connected, A current (ion current) flows between the fourth electrode 115 and this current always passes through the anion conductive electrolyte membrane 101 interposed between the first electrode 103 and the second electrode 102. Therefore, even in a single self-purging step, a considerably wide area of the anion conductive electrolyte membrane 101 (when the third electrode 110 and the fourth electrode 115 are arranged at almost the end of the membrane electrode assembly, the anion conductive electrolyte membrane 101 is used. Self-purging can be carried out for most areas).

(B) A wide range of self-purge in the membrane electrode assembly can be achieved by, for example, the second embodiment or the fourth embodiment, but according to the present embodiment, the adjacent electrodes are formed so as not to contact each other. Therefore, the complexity of the structure to be manufactured and the complexity of the manufacturing can be reduced, and the manufacturing cost can be reduced.

In the present embodiment, the arrangement configuration of the third electrode 110 and the fourth electrode 115 and the shape of these electrodes are not limited to those shown in FIGS. 13, 14, and 16, and the third electrode 110 to the fourth electrode 115 are not limited thereto. By providing the third electrode 110 and the fourth electrode 115 so that the shortest path to reach the inside of the anion conductive electrolyte membrane 101 interposed between the first electrode 103 and the second electrode 102 is provided. The advantageous effects shown in the above (a) and (b) can be obtained.

A plurality of third electrodes 110 and fourth electrodes 115 may be provided. For example, a position facing the fourth electrode 115 through the anion conductive electrolyte membrane 101 with respect to the membrane electrode assembly 50 shown in FIG. For example, a second third electrode 110 may be provided, and a second fourth electrode 115 may be provided at a position facing the third electrode 110 with the anion conductive electrolyte membrane 101 interposed therebetween.

(2) Method for Using Alkaline Fuel Cell Next, a method for using the alkaline fuel cell of this embodiment will be described. In the present embodiment, first, a reducing agent is supplied to the third electrode 110 through the first flow path 105 a of the third current collection layer 120, and to the fourth electrode 115 through the second flow path 104 a of the fourth current collection layer 125. The oxidizing agent is supplied, and the switching means 140 (connects the terminals B1 and B2 shown in FIG. 13), and the third current collecting layer 120 and the fourth current collecting layer 125 (therefore, the third electrode 110 and the fourth current collecting layer). The electrode 115) is electrically connected, and a current (ion current) is allowed to flow between the third electrode 110 and the fourth electrode 115 for a certain time [self-purging step]. By this step, a catalytic reaction such as the above formula (1) occurs in the fourth electrode 115, while a self purge reaction such as the above formulas (5) and (6) occurs in the third electrode 110 (partly, Catalytic reaction like the above formula (2) may also occur). By these reactions, the CO ₂ -derived anion in the anion conductive electrolyte membrane 101 including the region interposed between the first electrode 103 and the second electrode 102 moves to the third electrode 110 and is reduced by the reducing agent. , CO ₂ gas is discharged from the third electrode 110. In the self purge process, the fourth electrode 115 functions as a cathode electrode.

In the self-purge process, instead of supplying a reducing agent to the third electrode 110 and supplying an oxidizing agent to the fourth electrode 115, an oxidizing agent is supplied to the third electrode 110 and a reducing agent is supplied to the fourth electrode 115. You may do it. In this case, the third electrode 110 functions as a cathode electrode.

By performing the self-purge process, self-purge is performed over a wide range of the anion conductive electrolyte membrane 101, so that an increase in cell resistance can be effectively suppressed and the first electrode 103 functioning as an anode electrode during power generation The reaction overvoltage can be effectively reduced, and thus good power generation efficiency can be exhibited.

After the self-purging step, the electrical connection between the third electrode 110 and the fourth electrode 115 is cut, and then the reducing agent is supplied to the first electrode 103 through the first flow path 105a of the first current collecting layer 105. Then, the oxidizing agent is supplied to the second electrode 102 through the second flow path 104a of the second current collecting layer 104, and further, the first current collecting is performed by the switching means 140 (connecting terminals B3 and B4 shown in FIG. 13). Electric power is obtained by electrically connecting the layer 105 and the second current collecting layer 104 (therefore, the first electrode 103 and the second electrode 102) [power generation step]. As described above, since the accumulation of CO ₂ -derived anions does not easily occur in the first electrode 103 even by self-purge, good power generation efficiency can be exhibited.

The alkaline fuel cell of the present invention can be suitably applied as a power source for automobiles, home cogeneration, portable electronic devices, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

<Example 1>
The alkaline fuel cell 100 having the structure shown in FIG. 18 (the same structure as FIG. 1) was produced by the following procedure. 19 and 20 are schematic sectional views taken along lines XIX-XIX and XX-XX, respectively, shown in FIG.

(1) Preparation of membrane electrode composite An anion-conducting solid polymer electrolyte was obtained by chloromethylating a copolymer of aromatic polyether sulfonic acid and aromatic polythioether sulfonic acid and then aminating the copolymer. . By adding this to tetrahydrofuran, a 5 wt% anion conductive solid polymer electrolyte solution was obtained.

A catalyst-supporting carbon particle (“TEC10E50E” manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt-supporting amount of 50% by weight of Pt / C and the above-obtained electrolyte solution are in a weight ratio of 2 / 0.2. The catalyst paste for the 1st electrode 103, the 2nd electrode 102, and the 3rd electrode 110 was prepared by mixing and adding ion-exchange water and ethanol further.

Next, a fluororesin polymer electrolyte (“Aciplex” manufactured by Asahi Kasei Co., Ltd.) cut into a size of 8 cm × 8 cm is used as the anion conductive electrolyte membrane 101, and one side of the anion conductive electrolyte membrane 101 (first The catalyst paste of the second electrode 102 (cathode electrode) was formed by applying the catalyst paste at the center of the (2 surface) using a screen printing plate having a window of 5 cm length × 5 cm width and drying. . The size of the catalyst layer of the second electrode 102 is 5 cm long × 5 cm wide × about 10 μm thick.

In addition, the catalyst paste is applied to the center of the other surface (first surface) of the anion conductive electrolyte membrane 101 using a screen printing plate having a 1 cm long × 5 cm wide window and dried. A catalyst layer of the third electrode 110 was formed. The size of the catalyst layer of the third electrode 110 is 1 cm long × 5 cm wide × about 10 μm thick. Further, the catalyst paste is applied using a screen printing plate having a 1.5 cm long × 5 cm wide window and dried, whereby the first electrode 103 ( A catalyst layer of the anode electrode) was formed to obtain a membrane electrode assembly 10. The size of the catalyst layer of the first electrode 103 is 1.5 cm long × 5 cm wide × about 10 μm thick, and the distance between the catalyst layer of the first electrode 103 and the catalyst layer of the third electrode 110 is 0.5 cm. The region where the catalyst layer of the second electrode 102 is formed and the region where the catalyst layers of the first electrode 103 and the third electrode 110 are formed coincide with each other in the plane of the anion conductive electrolyte membrane 101.

(2) Production of alkaline fuel cell A serpentine-like groove (second flow path 104a, depth 0.3 cm) is formed by cutting on one side of a SUS plate having a length of 8 cm, a width of 8 cm, and a thickness of 1.5 cm. Two current collecting layers 104 (cathode side current collecting layers) were used. Also, insulative bonding of SUS plate of 3cm length × 8cm width × 1.5cm thickness / 1cm length × 8cm width × SUS plate of 1.5cm thickness / 3cm length × 8cm width × 1.5cm thickness SUS plate in this order After joining using the agent, a serpentine-like groove (first flow path 105a, depth 0.3 cm) is formed on one side by cutting, and the anode-side current collecting layer (that is, the first current collector in FIG. 18). Electrical layer 105 / insulating layer 130 / third current collecting layer 120 / insulating layer 130 / first current collecting layer 105).

On the catalyst layer of the second electrode 102 of the membrane electrode assembly 10 obtained above, a gas diffusion layer (GDL 35BC manufactured by SGL) cut into a size of 5 cm in length and 5 cm in width was stacked, and the obtained second electrode 102 was obtained. A silicone rubber sheet having an outer shape of 8 cm in length, 8 cm in width, and 200 μm in thickness and having an opening of 5 cm in length and 5 cm in width is arranged in the center as a gasket 106. Further, the second current collecting layer 104 was laminated so that the second flow path 104 a side was opposed to the second electrode 102. Further, a gas diffusion layer (GDL 35BC manufactured by SGL) cut into a size of 1.5 cm in length and 5 cm in width on the catalyst layer of the first electrode 103, 1 cm in length and 5 cm in width on the catalyst layer of the third electrode 110. A gas diffusion layer cut out in size (GDL35BC manufactured by SGL) is laminated, and the outer shape of the obtained electrode is a gasket 106. The outer shape is 8 cm long × 8 cm wide × 200 μm thick, and the center is 5 cm long × 5 cm wide. A silicone rubber sheet having openings formed therein was disposed. The anode-side current collection layer was laminated so that the first flow path 105a side was opposed to the first electrode 103 and the third electrode 110. The current collector layer on the anode side and the current collector layer on the cathode side are fastened with an insulation-coated bolt 150 and a nut 155, and the current collector layer is connected using external wiring 145 and switching means 140 as shown in FIG. The alkaline fuel cell 100 was obtained by wiring connection.

<Comparative Example 1>
Example 1 except that only the first electrode 103 having the same size (5 cm long × 5 cm wide × about 10 μm thick) as the second electrode 102 is formed at the center of the first surface of the anion conductive electrolyte membrane 101. Similarly, a membrane electrode assembly was produced to obtain an alkaline fuel cell.

<Example 2>
The alkaline fuel cell 300 having the structure shown in FIG. 21 (the same structure as FIG. 7) was produced by the following procedure. 22 and 23 are schematic cross-sectional views taken along lines XXII-XXII and XXIII-XXIII shown in FIG. 21, respectively (the cross-sectional structures on the anode electrode side are the same as those in FIGS. 19 and 20).

(1) Preparation of membrane electrode composite An anion-conducting solid polymer electrolyte was obtained by chloromethylating a copolymer of aromatic polyether sulfonic acid and aromatic polythioether sulfonic acid and then aminating the copolymer. . By adding this to tetrahydrofuran, a 5 wt% anion conductive solid polymer electrolyte solution was obtained.

The catalyst-supported carbon particles (“TEC10E50E” manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt-supported amount of Pt / C of 50% by weight and the above-obtained electrolyte solution have a weight ratio of 2 / 0.2. The catalyst paste for the 1st electrode 103, the 2nd electrode 102, the 3rd electrode 110, and the 4th electrode 115 was prepared by mixing and adding ion-exchange water and ethanol further.

Next, a fluororesin polymer electrolyte (“Aciplex” manufactured by Asahi Kasei Co., Ltd.) cut into a size of 8 cm × 8 cm is used as the anion conductive electrolyte membrane 101, and one side of the anion conductive electrolyte membrane (second The catalyst paste of the fourth electrode 115 was formed by applying the catalyst paste at the center of the surface) using a screen printing plate having a window of 1 cm length × 5 cm width and drying. The size of the catalyst layer of the fourth electrode 115 is 1 cm long × 5 cm wide × about 10 μm thick. Further, the catalyst paste is applied using a screen printing plate having a 1.5 cm long × 5 cm wide window and dried, so that the second electrode 102 ( Cathode electrode) catalyst layer was formed. The size of the catalyst layer of the second electrode 102 is 1.5 cm long × 5 cm wide × about 10 μm thick. The distance between the catalyst layer of the second electrode 102 and the catalyst layer of the fourth electrode 115 is 0.5 cm.

In addition, the catalyst paste is applied to the center of the other surface (first surface) of the anion conductive electrolyte membrane 101 using a screen printing plate having a 1 cm long × 5 cm wide window and dried. A catalyst layer of the third electrode 110 was formed. The size of the catalyst layer of the third electrode 110 is 1 cm long × 5 cm wide × about 10 μm thick. Further, the catalyst paste is applied using a screen printing plate having a 1.5 cm long × 5 cm wide window and dried, whereby the first electrode 103 ( A membrane electrode assembly 30 was obtained by forming a catalyst layer of the anode electrode). The size of the catalyst layer of the first electrode 103 is 1.5 cm long × 5 cm wide × about 10 μm thick, and the distance between the catalyst layer of the first electrode 103 and the catalyst layer of the third electrode 110 is 0.5 cm. The region where the catalyst layer of the second electrode 102 is formed and the region where the catalyst layer of the first electrode 103 is formed coincide with each other in the plane of the anion conductive electrolyte membrane 101. In addition, the region where the catalyst layer of the fourth electrode 115 is formed and the region where the catalyst layer of the third electrode 110 is formed coincide with each other in the plane of the anion conductive electrolyte membrane 101.

(2) Fabrication of alkaline fuel cell 3 cm long × 8 cm wide × 1.5 cm thick SUS plate / 1 cm long × 8 cm wide × 1.5 cm thick SUS plate / 3 cm long × 8 cm wide × 1.5 cm thick SUS plate Were joined in this order using an insulating adhesive, and then a serpentine-like groove (second flow path 104a, depth 0.3 cm) was formed by cutting on one side thereof to form a cathode-side current collecting layer. . Also, insulative bonding of SUS plate of 3cm length × 8cm width × 1.5cm thickness / 1cm length × 8cm width × SUS plate of 1.5cm thickness / 3cm length × 8cm width × 1.5cm thickness SUS plate in this order After bonding using the agent, a serpentine-like groove (first flow path 105a, depth 0.3 cm) was formed on one surface by cutting to form a current collecting layer on the anode side.

A gas diffusion layer (GDL 35BC manufactured by SGL) cut into a size of 1.5 cm in length and 5 cm in width on the catalyst layer of the second electrode 102 of the obtained membrane electrode assembly is placed on the catalyst layer of the fourth electrode 115. In addition, a gas diffusion layer (GDL 35BC manufactured by SGL Co., Ltd.) cut into a size of 1 cm in length × 5 cm in width is laminated, and the outer shape of the obtained electrode as a gasket 106 is 8 cm in length × 8 cm in width × 200 μm in thickness, A silicone rubber sheet in which an opening of 5 cm in length and 5 cm in width was formed in the center was disposed. Further, the cathode-side current collection layer was laminated so that the second flow path 104 a side was opposed to the second electrode 102 and the fourth electrode 115. Further, a gas diffusion layer (GDL 35BC manufactured by SGL) cut into a size of 1.5 cm in length and 5 cm in width on the catalyst layer of the first electrode 103, 1 cm in length and 5 cm in width on the catalyst layer of the third electrode 110. A gas diffusion layer cut out in size (GDL35BC manufactured by SGL) is laminated, and the outer shape of the obtained electrode is a gasket 106. The outer shape is 8 cm long × 8 cm wide × 200 μm thick, and the center is 5 cm long × 5 cm wide. A silicone rubber sheet having openings formed therein was disposed. Furthermore, the anode-side current collection layer was laminated so that the first flow path 105 a side was opposed to the first electrode 103 and the third electrode 110. The anode-side current collector layer and the cathode-side current collector layer are fastened with an insulation-coated bolt 150 and nut 155, and the current-collection layer is connected with external wiring 145 and switching means 140 as shown in FIG. The alkaline fuel cell 300 was obtained by wiring connection.

<Example 3>
The alkaline fuel cell 500 having the structure shown in FIG. 24 (the same structure as FIG. 13) was produced by the following procedure. 25 to 28 are schematic sectional views taken along lines XXV-XXV, XXVI-XXVI, XXVII-XXVII, and XXVIII-XXVIII shown in FIG.

(1) Preparation of membrane electrode composite An anion-conducting solid polymer electrolyte was obtained by chloromethylating a copolymer of aromatic polyether sulfonic acid and aromatic polythioether sulfonic acid and then aminating the copolymer. . By adding this to tetrahydrofuran, a 5 wt% anion conductive solid polymer electrolyte solution was obtained.

The catalyst-supported carbon particles (“TEC10E50E” manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt-supported amount of Pt / C of 50% by weight and the above-obtained electrolyte solution have a weight ratio of 2 / 0.2. The catalyst paste for the 1st electrode 103, the 2nd electrode 102, the 3rd electrode 110, and the 4th electrode 115 was prepared by mixing and adding ion-exchange water and ethanol further.

Next, a fluororesin polymer electrolyte (“Aciplex” manufactured by Asahi Kasei Co., Ltd.) cut into a size of 8 cm in length × 8 cm in width is used as the anion conductive electrolyte membrane 101, and one side of the anion conductive electrolyte membrane (second The catalyst paste of the fourth electrode 115 was formed by applying the catalyst paste on the right side of the surface) using a screen printing plate having a 1 cm long × 5 cm wide window and drying. The size of the catalyst layer of the fourth electrode is 1 cm long × 5 cm wide × about 10 μm thick. Further, the catalyst paste is applied using a screen printing plate having a 3.5 cm long by 5 cm wide window and dried, whereby the second electrode 102 (cathode) is formed on the left side of the catalyst layer of the fourth electrode 115. Electrode layer) was formed. The size of the catalyst layer of the second electrode 102 is 3.5 cm long × 5 cm wide × about 10 μm thick, and the distance between the catalyst layer of the second electrode 102 and the catalyst layer of the fourth electrode 115 is 0.5 cm.

In addition, by applying the catalyst paste to the left side of the other surface (first surface) of the anion conductive electrolyte membrane 101 using a screen printing plate having a 1 cm long × 5 cm wide window and drying, A catalyst layer of the third electrode 110 was formed. The size of the catalyst layer of the third electrode 110 is 1 cm long × 5 cm wide × about 10 μm thick. Further, the catalyst paste is applied using a screen printing plate having a 3.5 cm long by 5 cm wide window and dried, whereby the first electrode 103 (anode) is formed on the right side of the catalyst layer of the third electrode 110. Membrane electrode assembly 50 was obtained. The size of the catalyst layer of the first electrode 103 is 3.5 cm long × 5 cm wide × about 10 μm thick, and the distance between the catalyst layer of the first electrode 103 and the catalyst layer of the third electrode 110 is 0.5 cm. The region where the catalyst layer of the second electrode 102 is formed and the region where the catalyst layer of the first electrode 103 is formed coincide with each other in the plane of the anion conductive electrolyte membrane 101.

(2) Fabrication of alkaline fuel cell: 2.5 cm long × 8 cm wide × 1.5 cm thick SUS plate / 5 cm long × 8 cm wide × 1.5 cm thick SUS plate joined in this order using an insulating adhesive After that, a serpentine-like groove (second flow path 104a, depth 0.3 cm) was formed on one surface by cutting to form a cathode-side current collecting layer. Also, a SUS plate having a length of 5 cm × width 8 cm × thickness 1.5 cm / SUS plate having a length of 2.5 cm × width 8 cm × thickness 1.5 cm was joined in this order using an insulating adhesive, and then serpentine was formed on one surface thereof. A groove (first flow path 105a, depth 0.3 cm) was formed by cutting to form a current collecting layer on the anode side.

On the catalyst layer of the fourth electrode 115, a gas diffusion layer (GDL 35BC manufactured by SGL) cut into a size of 3.5 cm in length and 5 cm in width is formed on the catalyst layer of the second electrode 102 of the obtained membrane electrode assembly. In addition, a gas diffusion layer (GDL 35BC manufactured by SGL Co., Ltd.) cut into a size of 1 cm in length × 5 cm in width is laminated, and the outer shape of the obtained electrode as a gasket 106 is 8 cm in length × 8 cm in width × 200 μm in thickness, A silicone rubber sheet in which an opening of 5 cm in length × 5 cm in width was formed on the right side of the center. Further, the cathode-side current collection layer was laminated so that the second flow path 104 a side was opposed to the second electrode 102 and the fourth electrode 115. In addition, a gas diffusion layer (GDL 35BC manufactured by SGL) cut into a size of 3.5 cm in length and 5 cm in width on the catalyst layer of the first electrode 103, 1 cm in length and 5 cm in width on the catalyst layer of the third electrode 110. A gas diffusion layer (GDL35BC manufactured by SGL Co., Ltd.) cut into a size is laminated, and the outer shape of the obtained electrode as a gasket 106 is 8 cm long × 8 cm wide × 200 μm thick, and 5 cm long × 5 cm wide to the left of the center. A silicone rubber sheet having an opening was arranged. Furthermore, the anode-side current collection layer was laminated so that the first flow path 105 a side was opposed to the first electrode 103 and the third electrode 110. As shown in FIG. 24, the current collecting layer on the anode side and the current collecting layer on the cathode side are fastened with an insulation-coated bolt 150 and a nut 155, and the current collecting layer is connected using external wiring 145 and switching means 140. The alkaline fuel cell 500 was obtained by wiring connection.

[Evaluation of power generation characteristics of fuel cells]
(1) Alkaline fuel cell of Example 1 The alkaline fuel cell of Example 1 was placed in a constant temperature layer of 50 ° C., and H ₂ gas humidified using a humidifier set at a water temperature of 48 ° C. was used as the alkaline fuel cell. A flow rate of 100 mL / min is supplied to the first flow path 105a of the battery, and oxygen humidified using a humidifier set to a water temperature of 48 ° C. is supplied to the second flow path 104a of the alkaline fuel cell at a flow rate of 100 mL / min. Then, using the switching means 140, the second current collecting layer 104 and the third current collecting layer 120 were connected, and a current of 3A was circulated for 10 minutes. Subsequently, the switching means 140 is switched, the first current collecting layer 105 and the second current collecting layer 104 are connected, a current of 0.2 A / cm ² is passed, and the battery output after 5 minutes is measured. An output of 0.142 W / cm ² was obtained. The voltage at this time was 0.71 V, and the power generation efficiency was 58%. When the ohmic resistance of the fuel cell was measured using “Battery HiTester 3554” manufactured by Hioki Electric Co., Ltd., it was 150 mΩcm ² .

(2) Alkaline fuel cell of Example 2 The alkaline fuel cell of Example 2 was placed in a constant temperature layer of 50 ° C., and H ₂ gas humidified using a humidifier set at a water temperature of 48 ° C. was used as the alkaline fuel cell. Supplying the second flow path 104a of the battery at a flow rate of 100 mL / min and supplying oxygen humidified using a humidifier set to a water temperature of 48 ° C. to the first flow path 105a of the alkaline fuel cell at a flow rate of 100 mL / min Then, the switching means 140 was used to connect the first current collecting layer 105 and the fourth current collecting layer 125, and a current of 3A was circulated for 10 minutes. Next, H ₂ gas humidified using a humidifier set to a water temperature of 48 ° C. is supplied to the first flow path 105a of the alkaline fuel cell at a flow rate of 100 mL / min, and a humidifier set to a water temperature of 48 ° C. The oxygen that has been humidified is supplied to the second flow path 104a of the alkaline fuel cell at a flow rate of 100 mL / min, and the switching means 140 is switched to switch between the second current collecting layer 104 and the third current collecting layer 120. After connecting and flowing the current of 3A for 10 minutes, the switching means 140 is switched to connect between the first current collecting layer 105 and the second current collecting layer 104, and a current of 0.2 A / cm ² is passed. When the battery output after 5 minutes was measured, an output of 0.144 W / cm ² was obtained. The voltage at this time was 0.72 V, and the power generation efficiency was 59%. When the ohmic resistance of the fuel cell was measured using “Battery HiTester 3554” manufactured by Hioki Electric Co., Ltd., it was 150 mΩcm ² .

(3) Alkaline fuel cell of Example 3 The alkaline fuel cell of Example 3 was placed in a constant temperature layer of 50 ° C., and H ₂ gas humidified using a humidifier set to a water temperature of 48 ° C. was used as the alkaline fuel cell. A flow rate of 100 mL / min is supplied to the first flow path 105a of the battery, and oxygen humidified using a humidifier set to a water temperature of 48 ° C. is supplied to the second flow path 104a of the alkaline fuel cell at a flow rate of 100 mL / min. Then, using the switching means 140, the third current collecting layer 120 and the fourth current collecting layer 125 were connected, and a current of 3A was circulated for 10 minutes. Subsequently, the switching means 140 was switched, the first current collecting layer 105 and the second current collecting layer 104 were connected, a current of 0.2 A / cm ² was passed, and the battery output after 5 minutes was measured. An output of 0.138 W / cm ² was obtained. The voltage at this time was 0.69 V, and the power generation efficiency was 58%. The ohmic resistance of the fuel cell was measured using “Battery HiTester 3554” manufactured by Hioki Electric Co., Ltd. and found to be 162 mΩcm ² .

(4) Alkaline fuel cell of Comparative Example 1 The alkaline fuel cell of Comparative Example 1 was placed in a constant temperature layer of 50 ° C., and H ₂ gas humidified using a humidifier set to a water temperature of 48 ° C. was used as the alkaline fuel cell. A flow rate of 100 mL / min is supplied to the first flow path 105a of the battery, and oxygen humidified using a humidifier set to a water temperature of 48 ° C. is supplied to the second flow path 104a of the alkaline fuel cell at a flow rate of 100 mL / min. And the switching means 140 was used to connect between the first current collecting layer 105 and the second current collecting layer 104, a current of 0.2 A / cm ² was passed, and the battery output after 5 minutes was measured. However, an output of 0.134 W / cm ² was obtained. The voltage at this time was 0.67 V, and the power generation efficiency was 55%. When the ohmic resistance of the fuel cell was measured using “Battery HiTester 3554” manufactured by Hioki Electric Co., Ltd., it was 200 mΩcm ² .

10, 20, 30, 40, 50 membrane electrode composite, 100, 200, 300, 400, 500 alkaline fuel cell, 101 anion conductive electrolyte membrane, 102 second electrode, 103 first electrode, 104 second current collector Layer, 104a second flow path, 105 first current collecting layer, 105a first flow path, 106 gasket, 110 third electrode, 115 fourth electrode, 120 third current collecting layer, 125 fourth current collecting layer, 130 insulation Layer, 140 switching means, 145 external wiring, 150 bolts, 155 nuts.

Claims (15)

1. An anion conductive electrolyte membrane;
   A first electrode laminated on a first surface of the anion conductive electrolyte membrane;
   A second electrode laminated on a second surface of the anion conductive electrolyte membrane facing the first surface;
   A membrane electrode assembly for an alkaline fuel cell comprising:
   A membrane electrode assembly further comprising a third electrode stacked on the first surface and spaced apart from the first electrode.
2. The membrane electrode assembly according to claim 1, wherein the first electrode and the second electrode are provided to face each other with the anion conductive electrolyte membrane interposed therebetween.
3. The membrane electrode assembly according to claim 1, further comprising a plurality of third electrodes that are spaced apart from each other.
4. The membrane electrode assembly according to claim 3, wherein the plurality of third electrodes are substantially uniformly dispersed in the first surface.
5. The membrane electrode assembly according to claim 1, further comprising a fourth electrode laminated on the second surface so as to be separated from the second electrode.
6. The membrane electrode assembly according to claim 5, further comprising a plurality of fourth electrodes arranged apart from each other.
7. The membrane electrode assembly according to claim 6, wherein the plurality of fourth electrodes are arranged substantially uniformly in the second surface.
8. The first electrode and the second electrode are provided to face each other through the anion conductive electrolyte membrane,
   The third electrode disposed so that the shortest path from the third electrode to the fourth electrode passes through the anion conductive electrolyte membrane interposed between the first electrode and the second electrode; and The membrane electrode assembly according to claim 5, comprising four electrodes.
9. The third electrode is disposed on the outer side of the first electrode, and the fourth electrode is disposed on the outer side of the second electrode opposite to the side facing the third electrode. The membrane electrode assembly according to claim 8.
10. A membrane electrode assembly according to claim 1;
    A first current collecting layer laminated on the first electrode;
    A second current collecting layer laminated on the second electrode;
    A third current collecting layer laminated on the third electrode,
    An alkaline fuel cell in which the first current collecting layer and the third current collecting layer are electrically insulated.
11. A membrane electrode assembly according to claim 5;
    A first current collecting layer laminated on the first electrode;
    A second current collecting layer laminated on the second electrode;
    A third current collecting layer laminated on the third electrode;
    A fourth current collecting layer laminated on the fourth electrode;
    With
    An alkaline fuel cell in which the first current collecting layer and the third current collecting layer are electrically insulated, and the second current collecting layer and the fourth current collecting layer are electrically insulated.
12. A membrane electrode assembly according to claim 8;
    A first current collecting layer laminated on the first electrode;
    A second current collecting layer laminated on the second electrode;
    A third current collecting layer laminated on the third electrode;
    A fourth current collecting layer laminated on the fourth electrode;
    With
    An alkaline fuel cell in which the first current collecting layer and the third current collecting layer are electrically insulated, and the second current collecting layer and the fourth current collecting layer are electrically insulated.
13. A method of using the alkaline fuel cell according to claim 10,
    An oxidant is supplied to the second electrode, a reducing agent is supplied to the third electrode, the second electrode and the third electrode are electrically connected, and the second electrode and the third electrode A process of passing an electric current between
    Cutting an electrical connection between the second electrode and the third electrode;
    Supplying a reducing agent to the first electrode, supplying an oxidizing agent to the second electrode, and electrically connecting the first electrode and the second electrode to obtain electric power;
    Including usage.
14. A method of using the alkaline fuel cell according to claim 11,
    The first electrode and the fourth electrode are supplied by supplying an oxidizing agent to the first electrode, supplying a reducing agent to the fourth electrode, and electrically connecting the first electrode and the fourth electrode. A process of passing an electric current between
    Disconnecting an electrical connection between the first electrode and the fourth electrode;
    An oxidant is supplied to the second electrode, a reducing agent is supplied to the third electrode, the second electrode and the third electrode are electrically connected, and the second electrode and the third electrode A process of passing an electric current between
    Cutting an electrical connection between the second electrode and the third electrode;
    Supplying a reducing agent to the first electrode, supplying an oxidizing agent to the second electrode, and electrically connecting the first electrode and the second electrode to obtain electric power;
    Including usage.
15. A method of using the alkaline fuel cell according to claim 12,
    Either a reducing agent or an oxidizing agent is supplied to the third electrode, and either a reducing agent or an oxidizing agent is supplied to the fourth electrode, which is different from the agent supplied to the third electrode. Supplying and electrically connecting the third electrode and the fourth electrode to pass a current between the third electrode and the fourth electrode;
    Cutting an electrical connection between the third electrode and the fourth electrode;
    Supplying a reducing agent to the first electrode, supplying an oxidizing agent to the second electrode, and electrically connecting the first electrode and the second electrode to obtain electric power;
    Including usage.

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