TW201716232A - Anion exchanger, ion conductivity-imparting agent, catalyst electrode layer, membrane-electrode assembly, anion exchange membrane fuel cell and anion exchange membrane water electrolysis apparatus - Google Patents

Abstract

To provide an anion exchanger which is able to be used as an ion conductivity-imparting agent that is used in a fuel cell and a water electrolysis apparatus that use an anion exchange membrane, and which is capable of achieving a good balance among heat resistance, and insolubilization and ion exchange capacity increase of the ion conductivity-imparting agent. Heat resistance is imparted by using a styrene polymer wherein the chain length of an alkyl group between an ion exchange group and an aromatic ring is extended, and a good balance between insolubilization and high ion exchange capacity is able to be achieved by using a crosslinked structure that has a quaternary ammonium group as an ion exchange group.

Description

Anion exchanger, ion conductivity imparting agent, catalyst electrode layer, membrane-electrode assembly, anion exchange membrane type fuel cell, and anion exchange membrane type water electrolysis device

The present invention relates to an anion exchanger having heat resistance, an ion conductivity imparting agent, and a catalyst electrode layer. Further, the present invention relates to a novel laminate having the catalyst electrode layer, and a novel solid polymer fuel cell and a water electrolysis device comprising the laminate.

A fuel cell is a power generation system in which a chemical energy source of fuel is taken out as electric power, and several types of fuel cells such as an alkali type, a phosphoric acid type, a molten carbonate type, a solid electrolyte type, and a solid polymer type have been disclosed. Among these, the polymer electrolyte fuel cell is expected to be a small-sized low-temperature actuated fuel cell such as a fixed-place type power source or an in-vehicle use, in particular, because of its low operating temperature.

The polymer electrolyte fuel cell is a fuel cell using a solid polymer such as an ion exchange resin as an electrolyte. As shown in Fig. 1, the polymer electrolyte fuel cell has a basic structure in which the oxidant chamber side catalyst electrode layer 7 and the oxidant chamber side gas diffusion layer 6 on the oxidant chamber 10 side are high in solid state. The bonded body formed by joining the fuel cell side gas diffusion layer 4 and the fuel cell side catalyst electrode layer 5 on the fuel cell 9 side of the molecular electrolyte membrane 8 is separated from each other. The fuel passage hole 2 that communicates with the outside and the space in the battery partition wall 1 of the oxidant gas passage hole 3 form a fuel chamber 9 that communicates with the outside through the fuel passage hole 2, and communicates with the outside through the oxidant gas passage hole 3 The oxidant chamber 10. Further, in the polymer electrolyte fuel cell of such a basic configuration, fuel composed of a liquid such as hydrogen gas or alcohol is supplied to the fuel chamber 9 through the fuel gas flow hole 2, and the oxidant gas flow hole 3 is used. An oxygen-containing gas such as pure oxygen or air, which is an oxidant, is supplied to the oxidant chamber 10, and an external load circuit is connected between the fuel cell side catalyst electrode layer 5 and the oxidant chamber side catalyst electrode layer 7, and the following The mechanism produces electricity.

As the solid polymer electrolyte membrane 8, an anion exchange membrane has been studied as long as the reaction field becomes alkaline and a metal other than the noble metal can be used. At this time, by supplying hydrogen or alcohol to the fuel chamber 9, and supplying oxygen and water to the oxidant chamber 10, the catalyst contained in the electrode of the catalyst electrode side 7 in the oxidant chamber side and the oxygen and water are contained. Contact with to form hydroxide ions. This hydroxide ion is conducted in the solid polymer electrolyte membrane 8 composed of the anion exchange membrane and moved to the fuel chamber 9, and the fuel cell side catalyst electrode layer 5 reacts with the fuel to generate water. In response to this, the electrons generated in the fuel cell side catalyst electrode layer 5 are moved to the oxidant chamber side catalyst electrode layer 7 by the external load circuit, and the reaction energy is utilized as electric energy.

In general, a polymer electrolyte fuel cell using such an anion exchange membrane must exhibit high output power and further improve durability in order to be widely used. In order to obtain high output power, it is considered to increase the operating temperature of the polymer electrolyte fuel cell. However, when the operating temperature is raised, the anion exchanger forming the catalyst electrode layer, that is, the ion conductivity imparting agent The ion exchange group is deteriorated, and the anion exchanger is eluted from the catalyst electrode layer, so that the catalyst electrode layer is likely to be peeled off. As a result, the durability of the polymer electrolyte fuel cell is low.

The conventional anion exchanger is obtained by amination of a chloromethyl group of a copolymer of an aromatic polyether oxime and an aromatic polythioether oxime using a polyamine, and is obtained by crosslinking (Patent Document 1) a quaternized (chloromethyl)styrene/diethylbenzene copolymer using an amine (Patent Document 2); or a tetrabasic block copolymer having chloromethylated styrene using an amine Polymer (Patent Document 3) and the like. In Patent Document 1, the purpose of introducing a crosslinked structure is to reduce the methanol cross leak.

Here, in the case where the anion exchangers are focused on the 4-stage ammonium group of the anion exchange group, in either case, the chloromethyl group is substantially introduced and the anion exchange group is in the benzyl group position. Bonding to the aromatic ring. It is known that benzyl sites are generally susceptible to nucleophilic attack because of their high reactivity. On the other hand, it is known that by extending the chain length of the alkyl group between the quaternary ammonium base and the aromatic ring, the reactivity of the above-described quaternary ammonium salt can be remarkably suppressed, and the chemical stability of the exchange group can be improved (patent Document 4).

Prior technical literature

Patent literature

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-273695

[Patent Document 2] Japanese Patent Laid-Open No. Hei 11-135137

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2008-226614

[Patent Document 4] Japanese Patent Publication No. 04-349941

Patent Document 4 relates to a crosslinked anion exchanger having excellent heat resistance, which is a styrene monomer and an unsaturated hydrocarbon-containing product obtained by extending a chain length of an alkyl group between a quaternary ammonium group and an aromatic ring. It is composed of a polymer of a crosslinkable monomer. However, since it is insolubilized by introducing a crosslinkable monomer which does not contain an exchange group, there is a problem that the ratio of the ion exchange component is lowered due to introduction of the crosslinked structure.

In order to suppress the deterioration of the ion exchange group when the operating temperature of the polymer electrolyte fuel cell is increased, the use of the crosslinked anion exchanger described in Patent Document 4 as the ion conductivity imparting agent for forming the catalyst electrode layer can suppress Deterioration of ion exchange groups. However, in order to prevent elution of the anion exchanger from the catalyst electrode layer due to an increase in operating temperature, it is necessary to reduce the ratio of the ion exchange component and increase the ratio of the crosslinking component, thereby insolubilizing the ion conductive resin and high ion exchange. The problem that capacity is difficult to coexist.

The inventors of the present invention conducted intensive studies in order to achieve both heat resistance and inconsistency and high exchange capacity. As a result, it has been found that a styrene-based copolymer obtained by polymerizing a styrene monomer obtained by extending a chain length of an alkyl group between an ion-exchange group and an aromatic ring imparts heat resistance and has an introduction The crosslinked structure of the quaternary ammonium group as a function of the ion exchange group, the insolubilization and the high ion exchange capacity can coexist, and the present invention has been completed.

That is, the first invention is an anion exchanger containing a structural unit having a crosslinked structure represented by the following formula (1).

(Formula (1) is a structural unit in which two aromatic rings are crosslinked, a is an integer of 3 to 10, b is an integer of 2 to 8, and R ¹ , R ² , R ³ and R ⁴ are each independently selected from methyl or ethyl .X ^- selected from the group consisting of _{^{OH -, HCO 3 -, CO}} 3 2-, Cl -, Br -, I - the opposite ion of the group consisting of more than one).

The first aspect of the invention is an anion exchanger, and the polymer is contained in an amount of 70% by mass in order to exhibit excellent characteristics as an ion conductivity imparting agent and to obtain excellent characteristics and durability when used in a fuel cell or a water electrolysis device. The structural unit having the crosslinked structure represented by the formula (1) above is preferred.

The second invention is an ion conductivity imparting agent, and the polymer is composed of the first anion exchanger of the present invention containing 70% by mass or more of a structural unit having a crosslinked structure represented by the formula (1).

The third invention is a catalyst electrode layer containing the second ion conductivity imparting agent of the present invention and an electrode catalyst.

The fourth invention is a membrane-electrode assembly comprising a third The catalyst electrode layer of the present invention is formed.

The fifth invention is an anion exchange membrane type fuel cell comprising the fourth membrane-electrode assembly of the invention.

A sixth invention is a water electrolysis apparatus comprising the membrane-electrode assembly of the fourth invention.

According to a seventh aspect of the invention, there is provided a method for producing a catalyst electrode layer, comprising: coating a catalyst electrode layer forming composition containing a styrene polymer having an alkyl halide group in an aromatic ring and an electrode catalyst; A precursor of a diffusion electrode, an anion exchange membrane, or an anion exchange membrane is dried to form a catalyst electrode precursor layer, and then a styrene polymer having a halogenated alkyl group in the aromatic ring is brought into contact with the diamine compound. The fourth-stage and cross-linking reaction forms the catalyst electrode layer described in the third aspect of the invention.

The anion exchanger of the present invention imparts heat resistance to an ion exchange group by using a styrene polymer obtained by extending a chain length of an alkyl group between an ion exchange group and an aromatic ring, and is used by using As the ion exchange group, a crosslinked structure having a quaternary ammonium group can have a crosslinking ratio and a high ion exchange capacity by introducing a crosslinked structure into the anion exchanger.

Further, by using the ion exchanger of the present invention as an ion conductivity imparting agent and using a catalyst electrode layer containing the ion conductivity imparting agent and the electrode catalyst, it is used as an anion exchange membrane type fuel cell and a water electrolysis device. By increasing the crosslinking ratio, it is possible to prevent elution of the ion conductivity imparting agent caused by the increase in the operating temperature of the fuel cell and the water electrolysis device, and to increase the crosslinking ratio because the ion exchange group is used. Import to the cross-linking department Position, so it can maintain high ion conductivity. Moreover, the heat resistance of the anion exchange group is also improved.

1‧‧‧Battery partition

2‧‧‧Fuel circulation hole

3‧‧‧Oxidant gas flow holes

4‧‧‧fuel chamber side gas diffusion layer

5‧‧‧fuel chamber side catalyst electrode layer

6‧‧‧Oxygen chamber side gas diffusion layer

7‧‧‧Oxidant chamber side catalyst electrode layer

8‧‧‧Solid polymer electrolyte membrane (anion exchange membrane)

9‧‧‧fuel room

10‧‧‧ oxidizer room

11‧‧‧ Cathode side catalyst electrode layer

12‧‧‧Anode side catalyst electrode layer

13, 14‧‧‧ raw water supply pipe

15, 16‧‧‧ gas recovery pipe

20‧‧‧electrolyzer

30‧‧‧External power supply

31, 32‧‧‧ wires

Fig. 1 is a view showing an example of the structure of an anion exchange membrane type fuel cell.

Fig. 2 is a schematic view of a water electrolysis apparatus.

Form for implementing the invention

(anion exchanger)

First, the anion exchanger of the present invention will be described.

The anion exchanger of the present invention can be used as an ion conductivity imparting agent for forming a catalyst electrode layer for use in an anion exchange membrane type fuel cell and a water electrolysis device.

Here, the catalyst electrode layer means an anode in which a fuel gas such as hydrogen reacts, and a cathode which has reacted with an oxidant gas such as oxygen or air, and the use thereof is not particularly limited to one of the electrodes. It is a production of a catalyst electrode layer which can be suitably used for both an anode and a cathode.

The anion exchanger of the present invention contains a structural unit having a crosslinked structure represented by the following formula (1).

(wherein a is an integer of 3 to 10, b is an integer of 2 to 8, and R ¹ , R ² , R ³ and R ⁴ are each independently selected from a methyl group or an ethyl group. The X ^- series is selected from OH ^- , One or more relative ions of the group consisting of HCO ₃ ^- , CO ₃ ^2- , Cl ^- , Br ^- , and I ^- ).

The structural unit represented by the formula (1) is represented by -(CH ₂ ) _a N ⁺ (X ^- )R ¹ R ² (CH ₂ ) _b N ⁺ (X ^- )R ³ R ⁴ (CH ₂ ) _a - Two aromatic rings are crosslinked and have a group containing two quaternary ammonium salts.

a is an integer from 3 to 10, and b is an integer from 2 to 8. a represents a methylene chain length bonded to a nitrogen atom of a quaternary ammonium salt adjacent to an aromatic ring, and b represents a methylene chain length of nitrogen bonded to two quaternary ammonium salts. When a is less than 3, the chemical durability is insufficient, and when a is more than 10, the hydrophobicity of the methylene chain increases and the anion conductivity is inferior. The a is preferably in the range of 3 to 6.

Since the structural unit represented by the formula (1) has a crosslinked structure and contains two quaternary ammonium salts, it itself functions as an ion exchange group. Therefore, in order to contribute to the improvement in dimensional stability and chemical durability of the ion conductivity imparting agent by introducing a crosslinked structure, and exhibiting excellent ion conductivity, by -(CH ₂ ) _a N ⁺ (X ^- ) R ¹ R ² (CH ₂ ) _b N ⁺ (X ^- )R ³ R ⁴ (CH ₂ ) _a - is an important element for crosslinking. -(CH ₂ ) _a N ⁺ (X ^- )R ¹ R ² (CH ₂ ) _b N ⁺ (X ^- )R ³ R ⁴ (CH ₂ ) _a - not only the crosslinking site, but also the ions Conductivity must be designed. For the bonding of the methylene chain lengths of two quaternary ammonium bases, when it is too long, the hydrophobicity is increased and the ion conductivity is adversely affected. On the other hand, when it is too short, the nitrogen of the two quaternary ammonium salts is too Close to become a chemically unstable structure, so there are problems when it is too short. Therefore, the methylene chain length of the two quaternary ammonium salts is bonded, that is, b is in the range of 2 to 8, preferably in the range of 2 to 6.

R ¹ , R ² , R ³ and R ⁴ are each independently selected from methyl or ethyl.

The relative ion of the X ^- based quaternary basic anion exchange group is a relative ion selected from the group consisting of OH ^- , HCO ₃ ^- , CO ₃ ^2- , Cl ^- , Br ^- , and I ^- , which may be one type, or may be There are two or more kinds of relative ions mixed.

In the anion exchanger of the present invention, an ion conductivity imparting agent which is an anion exchange membrane type fuel cell and a catalyst electrode layer for water electrolysis can be used. When the anion exchanger of the present invention is used as the ion conductivity imparting agent, the structural unit having the crosslinked structure represented by the formula (1) has an ion conductivity imparting agent because it has a crosslinked structure and an ion exchange group as described above. The chemical stability and dimensional stability are also involved in the appearance of ion conductivity. In particular, when the operating temperature of the fuel cell and the water electrolysis device is 70 ° C or higher, it is known that the higher the introduction amount of the crosslinked structure, the higher the display durability tends to be. The reason for this is not clearly understood, and it is presumed that the insolubilization and the increase in mechanical strength obtained by crosslinking contribute to durability. Generally, the higher the operating temperature is, the elution of the anion exchanger as the ion conductivity imparting agent in the catalyst electrode layer, and the catalytic electricity. The structural change of the catalytic electrode layer caused by the swelling and contraction of the ion conductivity imparting agent in the electrode layer is more remarkable, and it is considered that the elution and structural change can be suppressed by introducing the crosslinked structure. Further, since the effect of improving the catalytic activity and the ion conductivity is improved by the high temperature, even if the introduction amount of the crosslinked structure is large, the battery output can be maintained high. Further, the anion exchanger as the ion conductivity imparting agent can ensure the presence of ion conductivity around the ion exchange group by the alkyl group between the ion exchange group and the aromatic ring in the crosslinked structure. A sufficient amount of water space does not impair ion conductivity even if the introduction amount of the crosslinked structure is increased. Therefore, in consideration of the operating conditions of the fuel cell, the target durability, the battery output, or the operating conditions of the water electrolysis device, the amount of the crosslinked structure introduced into the anion exchanger of the present invention may be determined, and the anion exchange may be suppressed. The ratio of the structural unit having the crosslinked structure represented by the formula (1) is preferably 70% by mass or more of the anion exchanger, and is preferably used at a high temperature of 70 ° C or higher. 1) The ratio of the structural unit shown is preferably 80% by mass or more.

The anion exchanger of the present invention having a content of the structural unit represented by the formula (1) of 70% by mass or more can impart heat resistance to the ion-exchange group, and can coexist with water insolubilization and high ion exchange capacity. Therefore, the anion exchanger can be suitably used as the ion conductivity imparting agent of the present invention used in the catalyst electrode layer of the anion exchange membrane type fuel cell and the water electrolysis device.

The anion exchanger of the present invention may be composed of any polymer as long as it contains a structural unit having a crosslinked structure represented by the formula (1). In terms of easiness of polymerization, crosslinking by diamine compound, easiness of quaternization reaction, crosslinking by diamine compound, and good physical properties after quaternization, By using a quaternary ammonium salt type anion exchange group, the terminal of the alkyl group extending from the aromatic ring of the polymer of the aromatic vinyl compound (hereinafter also referred to as "styrene polymer") is bonded to each other. A structural unit having a crosslinked structure represented by the formula (1) is preferred. Further, in the present specification, the polymer is used in the sense of containing a homopolymer and a copolymer.

The anion exchanger of the present invention may contain, in addition to the structural unit having a crosslinked structure represented by the formula (1), a first non-crosslinked quaternary ammonium salt type anion exchange group represented by the following formula (2). The structural unit (hereinafter also referred to simply as the first non-crosslinked structural unit).

(In the formula (2), c is an integer of 3 to 10, preferably 3 to 6, and R ⁵ and R ⁶ are each independently a methyl group or an ethyl group, and R ⁷ is a linear chain having 1 to 8 carbon atoms. alkyl .X ^- selected from the group consisting of _{^{OH -, HCO 3 -, CO}} 3 2-, Cl -, Br -, I - the opposite ion of the group consisting of more than one).

By introducing the first non-crosslinked structural unit represented by the above formula (2), the balance between hydrophilicity and hydrophobicity can be controlled, and when the anion exchanger of the present invention is used as an ion conductivity imparting agent, for example, even if it is operated Operating the fuel cell at low temperatures also maintains high ion conductivity. When the operating temperature is low, the ionic conductivity becomes low, but the first non-crosslinked structure list represented by the above formula (2) is introduced. The anion exchanger has an increased hydrophilicity and a high water content, and can improve ion conductivity. Further, when the operating temperature is low, the influence due to swelling and shrinkage is small, and the durability of the catalyst electrode layer containing the ion conductivity imparting agent is also small.

The content rate of the first non-crosslinked structural unit represented by the formula (2) of the anion exchanger of the present invention is prevented from increasing in temperature due to the use of the anion exchanger as an ion conductivity imparting agent. From the viewpoint of elution of the ion conductivity imparting agent, it is preferably 0 to 20% by mass, more preferably 0 to 10% by mass.

The anion exchanger of the present invention may be copolymerized with other components as needed in order to adjust the reactivity, the physical properties of the anion exchanger, and the like without departing from the object of the present invention. As such an optional component, an aromatic vinyl compound such as styrene, α-methylstyrene, vinylnaphthalene or enarene (Acenaphthylene) can be exemplified. The content ratio of the structural unit derived from other components is not particularly limited, but is preferably 0 to 10% by mass, particularly preferably 0 to 5% by mass.

In addition to the structural unit having the crosslinked structure represented by the formula (1), the anion exchanger of the present invention may contain a second non-crosslinked quaternary ammonium base represented by the following formula (3).

The anion exchanger of the present invention is obtained by crosslinking a styrene polymer having a halogenated alkyl group in an aromatic ring as described later with a diamine compound. When a styrene-based polymer having a halogenated alkyl group in an aromatic ring is brought into contact with a diamine compound, the diamine compound is reacted with two halogenated alkyl groups to form a structural unit represented by the formula (1), but only with 1 When the halogenated alkyl group is reacted, the second non-crosslinked quaternary ammonium base represented by the formula (3) is formed. The structural unit of the formula (3) has _a quaternary ammonium base represented by -(CH ₂ ) _a N ⁺ (X ^- )R ¹ R ² (CH ₂ ) _b NR ³ R ⁴ . a is an integer of 3 to 10, b is an integer of 2 to 8, and R ¹ , R ² , R ³ and R ⁴ are each independently a methyl group or an ethyl group. The X ^-term is selected from one or more kinds of relative ions consisting of OH ^- , HCO ₃ ^- , CO ₃ ^2- , Cl ^- , Br ^- , and I ^- . The preferred range of a and b is the same as in the formula (1).

Since the structural unit of the second non-crosslinked quaternary ammonium base represented by the formula (3) is a quaternary ammonium salt structure, even if it is formed, it has an effect on the performance of providing an ion conductivity imparting agent such as ion conductivity. It is also very small. Although the reason for this is not clear, it is known that the crosslinking reaction of the styrene-based polymer having a halogenated alkyl group in the non-crosslinked aromatic ring is carried out by using a diamine compound, so that the amount of the formula (3) can be suppressed to a very large extent. Among the diamine compounds which are small and participate in the reaction, the ratio of the structure of the formula (3) is obtained, and at most, it is about 10% by mole. This can be known by a commonly known C ¹³ solid state NMR method or titration method.

The polymerization mode of the anion exchanger of the present invention is not particularly limited, and the copolymer may be a random copolymer or a block copolymer.

The number average molecular weight of the styrenic polymer is preferably from 5,000 to 300,000, more preferably from 5,000 to 200,000.

The anion exchanger of the present invention can be obtained by containing formula (4) The structural unit represented by the reaction is obtained by reacting a styrene-based polymer having a halogenated alkyl group in an aromatic ring with a diamine compound.

In the formula (4), a is 3 to 10, preferably an integer of 3 to 6, and Y is any one of Cl, Br, and I.

(styrene-based polymer having a halogenated alkyl group in the aromatic ring)

The method for synthesizing the styrene-based polymer having a halogenated alkyl group in the aromatic ring is not particularly limited, and a method of polymerizing a polymerizable composition containing an aromatic vinyl compound having a halogenated alkyl group in the aromatic ring in advance; or A method of introducing a styrene polymer obtained by polymerizing an aromatic vinyl compound having a halogenated alkyl group after polymerization, and introducing an alkyl halide group into an aromatic ring of the styrene polymer.

When a polymerizable composition containing an aromatic vinyl compound having a halogenated alkyl group in the aromatic ring is polymerized, an aromatic vinyl compound having a halogenated alkyl group in the aromatic ring in advance can be polymerized by a conventional method. The aromatic vinyl compound having a halogenated alkyl group in the aromatic ring may be polymerized alone or may be copolymerized with another aromatic vinyl compound.

The aromatic vinyl compound having a halogenated alkyl group in the aromatic ring in advance is a carbon number in which a methylene chain in which an aromatic ring is bonded to a halogen atom is used. 3~10. Preferred examples of the aromatic vinyl compound include chloropropyl styrene, chlorobutyl styrene, chloropentyl styrene, chlorohexyl styrene, bromopropyl styrene, bromobutyl styrene, and bromopentyl group. The carbon number of the methylene chain in which the aromatic ring and the halogen atom are bonded to the styrene, bromohexyl styrene, iodopropyl styrene, iodobutyl styrene, iodopentyl styrene, and iodohexyl styrene is 3~ 6 haloalkylstyrene.

As an aromatic vinyl compound which has a halogenated alkyl group in the aromatic ring in advance, chloropropyl styrene, chlorobutyl styrene, and bromine are used from the viewpoints of easiness of obtaining and a large polymerization rate. Propyl styrene and bromobutyl styrene are preferred.

Examples of the other aromatic vinyl compound include styrene, α-methylstyrene, vinylnaphthalene, decene, vinylpyridine, vinylimidazole, and vinyl. Oxazoline and the like.

Further, the haloalkylstyrene having 7 or more carbon atoms in the unexemplified methylene chain is difficult to obtain in the present invention because the polymerization rate is also slow and gelation is likely to occur during polymerization. a copolymer of a molecular weight range in a preferred range, so that a styrene-based polymer having a halogenated alkyl group having a methylene chain of 7 or more in an aromatic ring is capable of introducing a halogenated alkane after polymerization by being described later. It is preferred that the aromatic vinyl compound is polymerized to obtain a styrene polymer, and a halogenated alkyl group is introduced into the aromatic ring of the styrene polymer.

The content of the aromatic vinyl compound having a halogenated alkyl group in the aromatic ring is preferably 70 to 100% by mass, and 90% by mass. 100% by mass Preferably.

Next, a method of polymerizing an aromatic vinyl compound capable of introducing a halogenated alkyl group after polymerization to obtain a styrene polymer, and introducing a halogenated alkyl group into the aromatic ring of the styrene polymer will be described. In this method, an aromatic vinyl compound having a structure capable of introducing a halogenated alkyl group is polymerized. After the polymerization, a halogenated alkyl group is introduced into the structure to obtain a styrene-based polymer having a halogenated alkyl group in the aromatic ring.

The styrene-based polymer which can introduce a halogenated alkyl group can be obtained by polymerizing styrene alone or by copolymerizing an aromatic vinyl compound other than styrene. Examples of the aromatic vinyl compound other than styrene include α-methylstyrene, vinylnaphthalene, decene, vinylpyridine, vinylimidazole, and vinyl. Oxazoline and the like. From the viewpoints of easiness of polymerization, ease of crosslinking reaction using a diamine compound, and ease of quaternization, it is preferred to use a styrene polymer obtained by polymerizing an aromatic vinyl compound alone. The method of introducing the halogenated alkyl group into the polymerized styrene polymer is not particularly limited, and a conventional method may be employed. Specifically, when styrene is used as the aromatic vinyl compound capable of introducing a halogenated alkyl group after polymerization, there is a method of reacting an aromatic ring derived from styrene with formaldehyde and then halogenating; and an aromatic ring derived from styrene After halogenation, an alkyl group is provided by a Grignard reaction, and a method of halogenating an alkyl chain terminal or the like is provided.

As a method of polymerizing a polymerizable composition containing an aromatic vinyl compound having a halogenated alkyl group in the aromatic ring or a polymerizable composition containing a monomer capable of introducing a halogenated alkyl group after polymerization, solution polymerization can be employed. A conventional polymerization method such as suspension polymerization or emulsion polymerization. Polymerization group The influence of the monomer composition and the like of the product may be appropriately selected without particular limitation.

(Ion exchange group introduction method)

The anion exchange system of the present invention can be produced by reacting the above-mentioned styrene-based polymer having a halogenated alkyl group in an aromatic ring with a diamine compound. That is, the anion exchanger of the present invention can be obtained by reacting a halogenated alkyl group of a styrene-based polymer having a halogenated alkyl group in an aromatic ring with an anion exchange group having a 4-stage ammonium salt type. The crosslinked structure formed, that is, the structural unit of the crosslinked structure represented by the formula (1).

Here, the diamine compound to be used may be a diamine compound having a crosslinked structure of a structural unit having a crosslinked structure represented by the formula (1), after appropriately selecting a quaternization reaction and a crosslinking reaction.

The alkyl diamine compound which can obtain the structural unit of the crosslinked structure represented by the formula (1) is preferably an alkyl diamine compound having a tertiary amine at both terminals represented by the following formula (5). Since the crosslinked structure formed by the alkyl diamine after the reaction is a quaternary ammonium salt, when the anion exchanger of the present invention is used in the case of the ion conductivity imparting agent, it is possible to contribute to the improvement of the necessary ion conductivity.

R ¹ R ² N (CH ₂ ) _b NR ³ R ⁴    (5)

In the formula (1), b, R ¹ , R ² , R ³ and R ^{4 are the} same, and in the formula (2), b represents a methylene chain length of two nitrogen atoms, and is an integer of 2 to 8. It is preferably in the range of 2 to 6, and R ¹ , R ² , R ³ and R ⁴ each independently represent a methyl group or an ethyl group.

Here, examples of the alkyldiamine compound to be used include ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexamethylenediamine, heptanediamine, and octanediamine.

Specifically, as the ethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, N,N-di can be exemplified. Methyl-N',N'-diethylethylenediamine, as propylenediamine, N,N,N',N'-tetramethylpropanediamine, N,N,N',N'- Tetraethyl propylene diamine, N, N-dimethyl-N', N'-diethyl propylene diamine; as butadiamine, N, N, N', N'-tetramethyl butyl Amine, N,N,N',N'-tetraethylbutanediamine, N,N-dimethyl-N',N'-diethylbutanediamine; as pentamethylenediamine, N,N can be exemplified , N', N'-tetramethylpentanediamine, N, N, N', N'-tetraethylpentanediamine, N, N-dimethyl-N', N'-diethylpentane Amine; as hexamethylenediamine, N,N,N',N'-tetramethylhexanediamine, N-ethylhexamethylenediamine, N,N,N',N'-tetraethylhexamethylenediamine can be exemplified , N,N-dimethyl-N',N'-diethylhexamethylenediamine; as the heptanediamine, N,N,N',N'-tetramethylheptanediamine, N,N, N', N'-tetraethylheptanediamine, N,N-dimethyl-N', N'-diethylheptanediamine; as octanediamine, N, N, N', N' can be exemplified -tetramethyloctanediamine, N,N,N',N'-tetraethyloctanediamine, N,N-dimethyl-N , N'- diethyl Kissin diamine.

Among these compounds, N, N, N', N' can be suitably used from the viewpoints of the easiness of the reaction, the chemical durability of the crosslinked structure formed after the reaction, and the degree of ion conductivity. -tetramethylbutanediamine, N,N,N',N'-tetramethylhexanediamine, N,N,N',N'-tetramethyloctanediamine.

The diamine compound represented by the formula (5) is reacted with two halogenated alkyl groups of the above-mentioned styrene polymer having an alkyl halide group in the aromatic ring to form a crosslink having two quaternary ammonium salts. structure. The following formula (6) schematically shows a formation reaction of a crosslinked structure, and two halogenated alkyl groups represented by (CH ₂ ) _a Y (Y is a halogen atom and are any one of Cl, Br, and I) Each of the tertiary amines at the terminal of the diamine compound undergoes a quaternary ammonium salt formation reaction to form a crosslinked structure.

-(CH ₂ ) _a Y+R ¹ R ² N(CH ₂ ) _b NR ³ R ⁴ +Y(CH ₂ ) _a - -(CH ₂ ) _a N ⁺ (X ^- )R ¹ R ² (CH ₂ ) _b N ⁺ (X ^- )R ³ R ⁴ (CH ₂ ) _a - (6)

In the above method, the method of contacting the diamine compound with the styrene polymer having a halogenated alkyl group in the aromatic ring is not particularly limited, and examples thereof include a styrene polymer obtained by drying a halogenated alkyl group in an aromatic ring. a method of contacting with a diamine compound; and a method of contacting the diamine compound in a solution after the styrene polymer having an aromatic ring having a halogenated alkyl group is dissolved. The reaction temperature is preferably carried out at a temperature of from 15 ° C to 40 ° C. When the reaction temperature is the former, the reaction time is preferably from 5 hours to 48 hours; when the reaction temperature is the latter, the polymer gel is caused by a long-term reaction. It is better to use 30 minutes to 1 hour.

After the styrene-based polymer having a halogenated alkyl group in the aromatic ring is brought into contact with the diamine compound, the excess diamine compound may be removed by a washing operation. Further, when the counter ion is a halogen ion, ion exchange with hydrogen hydroxide ions, hydrogen carbonate ions, carbonate ions, or the like can be performed. The method of ion exchange is not particularly limited, and a conventional method can be employed. After the exchange of the relative ions, the excess ions may be removed by washing.

(catalytic electrode layer)

The catalyst electrode layer of the present invention contains an ion conductivity imparting agent and an electrode catalyst composed of an anion exchanger having a content of a structural unit represented by the formula (1) of 70% by mass or more, and can be suitably used as an anion exchange. Membrane fuel cell And the catalyst electrode layer of the water electrolysis device.

The ion conductivity imparting agent comprising an anion exchanger having a content of a structural unit represented by the formula (1) of 70% by mass or more is used in a catalyst electrode layer of a fuel cell or a water electrolysis device, even if it is When the temperature is high, the ion exchange group does not deteriorate, and even if it is inside the fuel cell and the water electrolysis device, it does not elute in water, and the ion conductivity can be maintained high, and it has a long-term operation period. Good physical properties enable good fuel cell output, durability and water electrolysis performance.

The ionic conductivity imparting agent of the present invention may contain, in addition to the structural unit represented by the formula (1), the first non-crosslinked structural unit represented by the formula (2) and the second non-crosslinked structural unit represented by the formula (3). . Further, a method for producing a catalyst electrode layer for forming a precursor of a catalyst electrode layer on a precursor having an ion exchange membrane of a halogenated alkyl group as described later also includes an interface between the catalyst electrode layer and the ion exchange membrane. The styrene-based polymer having a halogenated alkyl group in the aromatic ring in the precursor of the catalyst electrode layer is crosslinked with the halogenated alkyl group of the precursor of the ion exchange membrane by a diamine, and is represented by the formula (1) The structural unit has a structure in which the ion conductivity imparting agent of the present invention and an ion exchange membrane are integrated.

The content of the structural unit represented by the formula (1) of the ion conductivity imparting agent of the present invention is 70% by mass or more, and the solubility in water and the swelling and shrinkage are reduced in order to maintain a high ion exchange capacity. The volume change is preferably 80% by mass or more.

Moreover, in order to achieve characteristics such as excellent anion conductivity and water retention, the ion exchange capacity of the ion conductivity imparting agent is preferably 2.8 to 5.0 mmol/g. As a value measured under conditions of 40 ° C and 90% RH, The water content is preferably from 10 to 100%. By having the ion exchange capacity and the water content in such a range, the ion conductivity imparting agent of the present invention is used in a fuel cell or a catalyst electrode layer of a water electrolysis device as described later, and is not dissolved in water to cause dissolution. Therefore, it is possible to achieve good durability during long-term operation.

The catalyst electrode layer of the present invention contains an electrode catalyst in addition to the ion conductivity imparting agent. A conventional catalyst can be used for the catalyst contained in the catalyst electrode layer. For example, platinum, gold, silver, palladium, rhodium, iridium, ruthenium, tin, iron, cobalt, nickel, molybdenum, tungsten, vanadium, which promote hydrogen oxidation reaction or hydrogen generation reaction and oxygen reduction reaction or oxygen generation reaction. Metal particles such as a lanthanoid metal or such an alloy can be used without limitation, but from the viewpoint of excellent catalyst activity, it is preferred to use a platinum group catalyst.

Further, the particle diameter of the metal particles of the catalyst is usually 0.1 to 100 nm, preferably 0.5 to 10 nm. The smaller the particle size, the higher the catalyst performance, but it is difficult to manufacture when it is less than 0.5 nm, and when it is more than 100 nm, sufficient catalyst performance is not easily obtained. Further, the catalysts may be used after being preliminarily loaded with a conductive agent. The conductive agent is not particularly limited as long as it is an electron conductive material. For example, carbon black such as furnace black or acetylene black, activated carbon, graphite or the like is used alone or in combination. The content of the catalyst is usually from 0.01 to 10 mg/cm ² , preferably from 0.1 to 5.0 mg/cm ² , based on the weight of the metal per unit area in a state in which the catalyst electrode layer is in a sheet form.

The catalyst electrode layer of the present invention may contain an electron conductivity imparting agent for the purpose of improving electron conductivity and having excellent properties. Examples of the electron conductivity imparting agent include carbon black, graphite, a carbon nanotube, a carbon nanohorn, and carbon fiber.

The content of the ion conductivity imparting agent and the electrode catalyst in the catalyst electrode layer and the amount ratio thereof reflect the structure of the catalyst electrode layer, and directly affect the electrochemical characteristics of the catalyst electrode layer. When the amount of the ion conductivity imparting agent is too small, the ion conductivity in the catalyst electrode layer is insufficient, which is not preferable. When the amount is too large, each electrode catalyst particle is thickened by the ion conductivity imparting agent. As a result, the contact between the catalyst particles is deteriorated, and the electron conductivity is low, which is not preferable. Therefore, it is very important to simultaneously adjust the ion conductivity and electron conductivity in the catalyst electrode layer in an appropriate range. From this point of view, the mass ratio of the electrode catalyst to the ion conductivity imparting agent differs depending on the structure of the particle size, the specific surface area, and the like of the electrode catalyst, and the mass of the electrode catalyst (ion/catalyst mass/ion) The conductivity imparting agent is preferably in the range of 99/1 to 30/70, and preferably in the range of 95/5 to 50/50.

The catalyst electrode layer of the present invention may contain a binder as necessary. As the binder to be added as needed, various thermoplastic resins can be usually used, and when a thermoplastic resin which can be suitably used is exemplified, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-perfluoroalkylethylene is exemplified. Ether copolymer, polyether ether ketone, polyether oxime, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and the like. When the binder is used, the content thereof is preferably 5 to 25% by weight based on the catalyst electrode layer. Further, the binder may be used singly or in combination of two or more types.

The thickness of the catalyst electrode layer is not particularly limited, and may be appropriately determined depending on the use to be used. It is usually preferably 0.1 to 50 μm, more preferably 0.5 to 20 μm.

(Method of Manufacturing Catalyst Electrode Layer)

The catalyst electrode layer of the present invention can be halogenated by containing an aromatic ring A styrene polymer (hereinafter also referred to as an ion conductivity imparting agent precursor) of an alkyl group and a catalyst electrode layer forming composition for an electrode catalyst are applied to a gas diffusion layer, an anion exchange membrane, or an anion exchange membrane. The precursor is dried to form a catalyst electrode precursor layer, and then contacted with a diamine compound in a solution containing a diamine compound to quaternize and crosslink the ion conductivity imparting agent precursor.

According to the method for producing a catalyst electrode layer of the present invention, the precursor of the catalyst electrode layer containing the precursor of the ion conductivity imparting agent can provide a quaternization reaction and a crosslinking reaction in a solution containing a diamine compound, because The dimensional change rate of the catalyst electrode layer itself before and after the reaction and the fine structure change inside the precursor of the catalyst electrode layer are remarkably small, so that a catalyst electrode having extremely excellent characteristics can be produced. Floor. That is, this is because the method of producing the catalyst electrode layer according to the present invention, before and after the crosslinking reaction between the ion conductivity imparting agent precursor before the reaction and the ion conductivity imparting agent obtained by the reaction The dimensional change rate is very small. For this reason, it is considered that the ratio of the diamine supplied to the quaternization reaction and the crosslinking reaction is high, so that the swelling of the ion conductivity imparting agent can be suppressed to a minimum.

As a factor which generally affects the characteristics of the catalyst electrode layer, electron conductivity in the catalyst electrode layer is known; the presence of internal pores formed by the catalyst particles and the ion conductivity imparting agent or ion conductivity imparting Gas diffusibility in the agent; ion conductivity in the ion conductivity imparting agent. The higher the ion conductivity in the electron conductivity or ion conductivity imparting agent in the catalyst electrode layer and the ion conductivity in the ion conductivity imparting agent, the better the catalyst electrode layer characteristics can be achieved.

In the method of producing a catalyst electrode layer, when the ion conductivity imparting agent is largely swelled in the crosslinking reaction, the electron conductivity imparting agent such as catalyst particles or carbon microparticles is coated or contacted with ions in the state of the precursor. In the conductivity imparting agent, the contact between the ion conductivity imparting agent and the catalyst particles responsible for electron conduction or the electron conduction imparting agent is deteriorated due to swelling, and the electron conductivity is lowered, so that the characteristics of the catalyst electrode layer are lowered. Further, since the swelling of the ion conductivity imparting agent occludes the internal pores formed inside the catalyst electrode precursor layer, the gas diffusibility is also lowered. For this reason, when the ion conductivity imparting agent in the catalyst electrode layer is largely swollen, the characteristics of the catalyst electrode layer are insufficient.

Moreover, when the swelling of the ion conductivity imparting agent is large, the size of the catalyst electrode layer itself increases. In other words, since the size in the state of the precursor is increased after the quaternization and the crosslinking reaction, it is likely to be inconsistent with the size of the fuel unit during power generation. When the area of the catalyst electrode layer is larger than the size of the fuel cell unit that is most suitable for use, most of the cases are difficult to maintain airtightness inside the cell and cause air leakage, etc., not only to improve the efficiency of the fuel cell. It is low and it is dangerous even when using a fuel such as hydrogen. Such a size change of the catalyst electrode layer in the cross-linking and quaternization reaction is not only a problem of productivity, but also affects power generation efficiency and safety.

When the water electrolysis device is used, since the catalyst electrode layer is directly in contact with the liquid, the ion conductivity imparting agent has a large influence on swelling due to water absorption, and the catalyst is detached due to the dimensional change of the catalyst electrode layer and the electrode reaction is caused. The generated gas stays in the catalyst electrode layer, so that the electrolysis efficiency is remarkably lowered. Further, the pressure in the electrolytic cell rises due to gas retention, and the gas is leaked. This is not only to make the electrolysis efficiency low, but also because the gas produced is hydrogen, and even dangerous. As described above, in the cross-linking and quaternization reaction, the size of the catalyst electrode layer changes greatly, which also affects the decrease in electrolysis efficiency or safety.

According to the present invention, it is possible to obtain not only a catalyst electrode layer having excellent characteristics but also the productivity of the catalyst electrode layer, the power generation efficiency of the fuel cell using the same, the electrolysis efficiency of the water electrolysis device, and safety. Enjoy excellent results.

Hereinafter, a method of manufacturing the catalyst electrode layer will be described.

(Composition for forming a catalyst electrode layer)

At the time of formation of the catalyst electrode layer, a dispersion liquid composed of an electrode catalyst, an ion conductivity imparting agent precursor, or the like can be prepared and applied to an anion exchange membrane or a gas diffusion layer. (hereinafter, a dispersion liquid containing an electrode catalyst or an ion conductivity imparting agent precursor is referred to as a catalyst electrode layer forming composition, and a layer formed by coating the layer is referred to as a catalyst electrode precursor layer).

The catalyst electrode layer forming composition contains an ion conductivity imparting agent precursor and an electrode catalyst, and may further contain a solvent or an electron conductivity imparting agent as needed.

The ion conductivity imparting agent precursor may be a solid in the catalyst electrode layer forming composition, or may be in a dissolved state, and is not particularly limited. When the catalyst particles of the catalyst electrode layer are uniformly coated and the ion conductivity imparting agent after crosslinking is uniformly coated, the electrochemical function of the catalyst can be exhibited and the catalyst electrode layer is high. Activated. Therefore, when a solvent is added to the ion conductivity imparting agent precursor to carry out the solution of the ion conductivity imparting agent precursor, The electrode catalyst is uniformly dispersed in the dispersion liquid, and the surface thereof is sufficiently coated with the ion conductivity imparting agent precursor to obtain a catalyst electrode layer having excellent characteristics.

The solvent to be used for the solution of the precursor of the ion conductivity imparting agent is not particularly limited, and the precursor of the ion conductivity imparting agent itself can be well dissolved, and the affinity with the catalyst fine particles can be improved and can be improved. For the purpose of obtaining a higher dispersion state, it is preferred to use a polar solvent. As such a solvent, tetrahydrofuran, two can be exemplified A cyclic ether such as an alkane is an organic solvent; an alcohol such as methanol, ethanol, propanol or isopropanol; water; an ester such as ethyl acetate; a cyclic hydrocarbon such as cyclohexane. Further, these mixed solvents can also be used.

The method of solubilization is not particularly limited, and a method of simply adding an ion conductivity imparting agent precursor to a solvent and stirring it is simple. Depending on the composition or solvent composition of the ion conductivity imparting agent precursor, it is also possible to promote dissolution by heating. The dissolution system is preferably carried out at a temperature of 15 ° C or higher and a boiling point of the solvent or not.

The concentration of the ion conductivity imparting agent precursor solution is not particularly limited. When the concentration of the solution is too high, the viscosity of the solution is usually remarkably high, and the operation at the time of forming the catalyst electrode layer causes a problem, and it takes time from the solution. The viscosity of the solution is preferably set to a lower concentration, and the concentration of the ion conductivity imparting agent precursor in the entire solution is preferably from 1 to 20% by mass.

(catalyst for catalyst electrode layer)

An electrode catalyst used in the method for producing a catalyst electrode layer of the present invention will be described. As described above, the catalyst for the catalyst electrode layer can be a conventional catalyst. For example, platinum, gold, silver, palladium, which promote the oxidation reaction of hydrogen and the reduction reaction of oxygen. Metal particles such as ruthenium, osmium, iridium, tin, iron, cobalt, nickel, molybdenum, tungsten, vanadium, or the like can be used without limitation, since the catalyst activity is excellent, and the platinum catalyst is used. good.

Further, the particle diameter of the metal particles of the catalyst is usually 0.1 to 100 nm, preferably 0.5 to 10 nm. The smaller the particle size, the higher the catalyst performance, but it is difficult to manufacture in the case of less than 0.5 nm, and it is not easy to obtain sufficient catalyst performance when it is larger than 100 nm. Further, the catalysts may be used after being preliminarily loaded with a conductive agent. The conductive agent is not particularly limited as long as it is an electron conductive material. For example, carbon black such as furnace black or acetylene black, activated carbon, graphite or the like is used alone or in combination. The content of the catalyst is usually from 0.01 to 10 mg/cm ² , preferably from 0.1 to 5.0 mg/cm ² , based on the weight of the metal per unit area in a state in which the catalyst electrode layer is in a sheet form.

In order to improve the electron conductivity of the catalyst electrode layer and to obtain excellent characteristics, an electron conductivity imparting agent may be added to the composition. Examples of the electron conductivity imparting agent include carbon black, graphite, a carbon nanotube, a carbon nanohorn, and carbon fiber.

The amount of the ion conductivity imparting agent precursor and the electrode catalyst added to the catalyst electrode layer forming composition and the amount ratio thereof have a large influence on the structure of the obtained catalyst electrode precursor layer. The selection directly affects the electrochemical properties of the catalytic electrode layer. When the ion conductivity imparting agent precursor is too small, when the catalyst electrode layer is used, the ion conductivity is insufficient, which is not preferable. On the contrary, since the electrode catalyst particles are ion-conducting. Since the imparting agent is thickly coated, the contact between the particles is deteriorated and the electron conductivity is low, which is not preferable. Therefore, ion conductivity and electron propagation in the catalyst electrode layer Simultaneous adjustment of the conductivity is very important in the appropriate range. From this point of view, the mass ratio of the electrode catalyst to the ion conductivity imparting agent precursor differs depending on the structure of the electrode catalyst, the specific surface area, or the like, or the structure of the ion conductivity imparting agent. The catalyst mass/ion conductivity imparting agent precursor mass is preferably in the range of 99/1 to 40/60, and preferably in the range of 95/5 to 50/50.

The catalyst electrode layer forming composition of the present invention may contain a binder as needed. As the binder to be added as needed, various thermoplastic resins can be usually used, and when a thermoplastic resin which can be suitably used is exemplified, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-perfluoroalkylethylene is exemplified. Ether copolymer, polyether ether ketone, polyether oxime, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and the like. The content of the binder in the catalyst electrode layer-forming composition is preferably from 5 to 25% by weight based on the amount of the catalyst electrode layer. Further, the binder may be used singly or in combination of two or more types.

The catalyst electrode layer forming composition can be obtained by mixing at least an ion conductivity imparting agent precursor, an electrode catalyst, and an optional electron conductivity imparting agent in a solvent. In order to obtain a high-performance catalyst electrode layer, the electrode catalyst is preferably in a highly dispersed state in the composition. Therefore, a method in which the electrode catalyst is in a highly dispersed state can be suitably employed as a mixing method. Examples of the dispersing device include a bead mill, a ball mill, a high-pressure collision type dispersing device, and an ultrasonic dispersing machine, and may be selected according to the state of aggregation of the electrode catalyst to be used and energy necessary for dispersion, time, temperature, and the like. The mixing conditions are also determined in the same manner.

In addition, the viscosity of the catalyst electrode layer-forming composition is not particularly limited as long as it is suitable for a coating method to be described later. Viscosity is strongly dependent The state of dispersion of the electrode catalyst and the amount of solvent added to the composition. The amount of the solvent to be added may be determined such that the amount of the ion conductivity imparting agent precursor and the electrode catalyst is 0.1 to 10% by mass.

(Method of forming precursor layer of catalyst electrode)

In the method for producing a catalyst electrode layer of the present invention, the catalyst electrode layer forming composition is applied to a gas diffusion layer or an anion exchange membrane, and after forming a catalyst electrode precursor layer, the catalyst electrode layer is used. And a case where it is applied to a precursor of an ion exchange membrane having a halogenated alkyl group as a catalyst electrode layer after forming a catalyst electrode precursor layer.

The coating method of the catalyst electrode layer-forming composition is not particularly limited, and may be determined according to characteristics such as the application target and the thickness of a desired catalyst electrode layer. As the method, spray coating, bar coating, roll coating, gravure printing, screen printing, and the like can be exemplified.

The coated catalyst electrode precursor layer is dried at an appropriate temperature. The drying conditions are not particularly limited, and the range in which the catalyst electrode precursor layer does not cause cracks, pinholes, or the like during drying may be determined depending on the amount of the solvent to be used, the boiling point, and the like. It is usually preferred to carry out drying at a temperature of 15 to 70 ° C for 5 to 48 hours.

The thickness of the catalyst electrode precursor layer formed on the object to be coated is not particularly limited, and may be appropriately determined depending on the intended use. It is usually preferably 1 to 50 μm, more preferably 0.5 to 20 μm.

As described above, in the method for producing a catalyst electrode layer of the present invention, the catalyst electrode layer forming composition is applied to the gas diffusion layer or the catalyst electrode layer forming composition is applied to the anion exchange membrane. Situation; and will touch The composition for forming a dielectric electrode layer is applied to a precursor of an ion exchange membrane having a halogenated alkyl group.

A method of producing a catalyst electrode layer by first applying a composition for forming a catalyst electrode layer on a gas diffusion layer or an anion exchange membrane will be described.

(When the catalyst electrode precursor layer is formed on the gas diffusion layer or the anion exchange membrane)

The catalyst electrode precursor layer formed on the gas diffusion layer or the anion exchange membrane may be subjected to quaternization and crosslinking in a solution containing a diamine compound.

The method for forming the catalyst electrode precursor layer is not limited by the object to which the catalyst electrode layer forming composition is applied, and the above method may be used.

Examples of the gas diffusion layer include carbon paper, carbon cloth, nickel foam, titanium foam, foamed metal, and the like, and porous graphite can be used without particular limitation. Usually used in the case of a fuel cell, carbon paper or carbon cloth is preferred. Usually, when water electrolysis is used, it is preferred to select a nickel foam or a titanium foam. Further, when the gas diffusion layer is used in a fuel cell, in order to easily discharge water generated by power generation out of the system, or to suppress drying of the film-electrode assembly when a dry gas or the like is used, there is also a carbon black. And a fine porous layer composed of a binder such as polytetrafluoroethylene; however, the present invention can be used without particular limitation. Similarly, in the case of using a water electrolysis device, a gas diffusion layer having a fine porous layer can be used for the purpose of easily discharging hydrogen generated by electrolysis to the outside of the system. The gas diffusion layer is not particularly limited, and a porous film made of carbon is preferable. For example, carbon fiber woven fabric, carbon paper, or the like can be used. The thickness of the gas diffusion layer is preferably 50 to 300 μm, and the void ratio is preferably 50 to 90%. In the present invention, When the catalyst electrode layer is formed by post-crosslinking, it is preferred to use the carbon-based porous material. For this reason, after the catalyst electrode precursor layer is formed, the catalyst electrode precursor layer is brought into contact with the diamine compound, and at this time, the carbon porous film is not deformed by swelling or the like.

Further, when the catalyst electrode layer is formed on the anion exchange membrane, the anion exchange membrane is not particularly limited, and a conventional anion exchange membrane can be used. In particular, it is preferred to use a hydrocarbon-based anion exchange membrane. Specifically, a film filled with an anion exchange resin in which an chloromethylstyrene-divinylbenzene copolymer, a vinylpyridine-divinylbenzene copolymer, or the like is passed through an amine is exemplified. A treatment such as a base or an alkylation is carried out to introduce a desired anion exchange group. The anion exchange membrane is usually supported by a base material such as a woven fabric, a nonwoven fabric, or a porous film made of a thermoplastic resin, and has a low gas permeability and can be made into a film. As the base material, polyethylene is used. A porous film made of a thermoplastic resin such as a polyolefin resin such as polypropylene or polymethylpentene, or a fluorine-based resin such as polytetrafluoroethylene, poly(tetrafluoroethylene-hexafluoropropylene) or polyvinylidene fluoride. The substrate to be formed is preferred. Moreover, the thickness of the hydrocarbon-based anion exchange membrane is preferably from 5 to 200 μm, from the viewpoint of suppressing the electric resistance to be low and imparting mechanical strength necessary for the support film. It is preferred to have a thickness of 8 to 150 μm.

(Method of cross-linking and quaternization reaction)

Next, the catalyst electrode precursor layer formed on the gas diffusion layer or the anion exchange membrane is subjected to quaternization and crosslinking in a solution containing a diamine compound. Since the crosslinking reaction using the diamine compound is easy to proceed, the halogenated alkyl group of the ion conductivity imparting agent precursor in the catalyst electrode precursor layer can contain two The solution of the amine compound is quaternized and crosslinked.

When the ion conductivity imparting agent precursor is quaternized and crosslinked by using a diamine compound, the dimensional change of the ion conductivity imparting agent before and after the quaternization and the crosslinking reaction can be suppressed to be small. This is because the ion conductivity imparting agent precursor is crosslinked while being quaternized in the solution containing the diamine compound, and the ionic conductivity imparting agent having a crosslinked structure can suppress swelling and shrinkage. This feature exhibits the function of suppressing dimensional changes during the manufacturing process of the catalyst electrode layer, and is used to obtain an effective function of a very high performance catalyst electrode layer.

The diamine compound used herein can form a structural unit having a crosslinked structure represented by the formula (1) after the quaternization and crosslinking reaction, and appropriately selects the production of the anion exchanger of the present invention described above. The diamine compound of the formula (5) used may be used.

The method of contacting the diamine compound and the catalyst electrode precursor layer may be a method suitable for producing a catalyst electrode layer containing an ion conductivity imparting agent having a crosslinked structure. Specifically, a method of immersing the catalyst electrode precursor layer in a solution containing a diamine compound diluted with a solvent, if necessary, and spraying a solution containing a diamine compound on the catalyst may be mentioned. The method of the electrode precursor layer and the like. In particular, it is preferred to use a method of impregnating it.

The amount of the diamine compound to be used in the formation of the crosslinked structure is determined according to the type of the diamine compound, the halogenated alkyl group contained in the precursor of the ion conductivity imparting agent, the degree of crosslinking desired, and the ion exchange capacity. It can be decided appropriately. Specifically, it will be contained in the precursor of the ion conductivity imparting agent. When the total number of moles of the halogenated alkyl group is set to n1, the amount of the diamine compound to be used is preferably 0.7 mol or more of n1, more preferably equal to or more than the molar ratio.

When the catalyst electrode layer of the present invention is produced by reacting a catalyst electrode precursor layer with a diamine compound, the crosslinking agent represented by the formula (1) is used in addition to the essential component of the ion conductivity imparting agent by using a tertiary amine in combination. In addition to the structural unit of the structure, the first non-crosslinked structural unit represented by the following formula (2) can also be introduced. By introducing the first non-crosslinked structural unit represented by the following formula (2), the balance between the hydrophilicity and the hydrophobicity of the catalyst electrode layer of the present invention can be controlled. When the operating temperature is low, the ionic conductivity is low. However, by introducing the first non-crosslinked structural unit represented by the above formula (2), the hydrophilicity of the catalytic electrode layer is increased and the water content is increased, whereby ion conduction can be improved. degree. Further, when the operating temperature is low, the influence due to swelling and shrinkage is small, and the durability of the catalyst electrode layer is also reduced. In order to prevent elution of the ion conductivity imparting agent due to the increase in the operating temperature, the content ratio of the first non-crosslinked structural unit represented by the formula (2) is preferably 0 to 20% by mass, and 0 to 10% by mass. good.

(In the formula (2), c is an integer of 3 to 10, preferably 3 to 6, and R ⁵ and R ⁶ are each independently a methyl group or an ethyl group, and R ⁷ is a linear chain having 1 to 8 carbon atoms. alkyl .X ^- selected from the group consisting of _{^{OH -, HCO 3 -, CO}} 3 2-, Cl -, Br -, I - the opposite ion of the group consisting of more than one).

As the tertiary amine, a tertiary amine having a structure represented by the formula (2) can be appropriately selected after the introduction. Specifically, trimethylamine, triethylamine, dimethylethylamine, dimethylpropylamine, dimethylbutylamine, dimethylpentylamine, dimethylhexylamine, dimethylheptylamine, and dimethyl are exemplified. Benzylamine, diethylmethylamine, diethylpropylamine, diethylbutylamine, diethylpentylamine, diethylhexylamine, diethylheptylamine, diethyloctylamine, ethylmethylpropylamine Ethylmethylbutylamine, ethylmethylpentylamine, ethylmethylhexylamine, ethylmethylheptylamine, ethylmethyloctylamine, and the like.

As a tertiary amine, trimethylamine, triethylamine, dimethylbutylamine, dimethylhexylamine, dimethyloctylamine, diethylbutylamine is used for reasons such as high reactivity and ease of availability. Ethylhexylamine and diethyloctylamine are preferred.

When a tertiary amine is used in combination, any one of the following methods may be employed: a method in which a mixture of a diamine compound and a tertiary amine is contacted with the catalyst electrode precursor layer of the present invention; and a method of contacting the diamine compound after contacting the tertiary amine And a method of contacting the tertiary amine after contacting the diamine compound.

The amount of the tertiary amine to be used may be determined in accordance with the degree of the desired degree of crosslinking, taking into consideration the ratio of the diamine compound to be used. When the monofunctional quaternizing agent (the tertiary amine) is largely reacted with the halogenated alkyl group, as described above, the swelling of the ion conductivity imparting agent in the post-crosslinking reaction becomes large because of the ion conductivity imparting agent of the present invention. The effect of suppressing the swelling in the crosslinking reaction is not exhibited, so that the characteristics of the present invention are not exhibited, which is not preferable. Therefore, when the tertiary amine and the diamine compound are used simultaneously or in combination, the reaction is carried out in relation to the halogenated alkyl group 1 having an ion conductivity imparting agent contained in the catalyst electrode precursor layer. The amine is preferably 0.3 mol or less, more preferably 0.2 mol or less. Further, it is preferably 0.01 mol or more.

However, the amount of the halogenated alkyl group, the diamine compound, and the tertiary amine used as needed in the precursor of the ion conductivity imparting agent is preferably equal to or more than the same amount.

Further, the solution containing the diamine-containing compound may further contain a solvent. However, when the tertiary amine is not used, that is, when the diamine compound is used alone in the reaction, since the concentration of the diamine in the reaction does not change, the reaction rate is not affected, and it is preferred to use no solvent.

The solvent to be used is not particularly limited as long as it does not dissolve the constituent components of the catalyst electrode precursor layer, and water, methanol, ethanol, propanol or the like, and ketone such as acetone can be suitably used. Classes, etc.

The reaction temperature is preferably from 15 ° C to 40 ° C, and the reaction time is preferably from 5 hours to 48 hours, and from the viewpoint of improving productivity, from 5 hours to 24 hours is preferred.

After the catalyst electrode precursor layer is brought into contact with the diamine compound, the excess diamine compound may be removed by a washing operation.

Further, when the counter ion is a halogen ion, ion exchange with hydrogen hydroxide ions, hydrogen carbonate ions, carbonate ions, or the like can be performed. The ion exchange method is not particularly limited, and a conventional method can be employed. After the relative ion exchange, the excess ions may be removed by washing.

Next, a method of producing a catalyst electrode layer formed on a precursor of an ion exchange membrane will be described.

(When a catalyst electrode precursor layer is formed on the precursor of the anion exchange membrane)

In the present invention, it is also possible to pass the ion exchange membrane having a halogenated alkyl group. A catalyst electrode precursor layer is formed on the substrate, and a catalyst layer is formed by performing a quaternization and a crosslinking reaction in a solution containing a diamine compound.

In the above production method, since not only the crosslinking reaction of the ionic conductivity imparting agent precursor having a diamine in the catalyst electrode precursor layer but also the halogenated alkyl group is produced, and also contained in the catalyst electrode precursor layer The halogenated alkyl group of the ion conductivity imparting agent precursor and the halogenated alkyl group of the ion exchange membrane precursor have a crosslinking reaction, so that the catalyst electrode layer and the anion exchange membrane can be obtained by crosslinking. Membrane-electrode assembly.

The precursor of the anion exchange membrane having a halogenated alkyl group means a precursor having an ion exchange membrane capable of introducing an ion exchange group, which is produced by a conventional method for producing an anion exchange membrane. For example, a precursor of a hydrocarbon-based anion exchange membrane may be exemplified, and specifically, a membrane filled with a chloromethylstyrene-divinylbenzene copolymer or a bromobutylstyrene-divinylbenzene copolymer may be mentioned. . The copolymer contained in the precursor of the anion exchange membrane is usually supported by a substrate such as a thermoplastic woven fabric, a nonwoven fabric, or a porous film, but the gas permeability is low and the film can be formed. In other words, as the substrate, a polyolefin resin such as polyoctane, polypropylene, polymethylpentene, polytetrafluorooctane, poly(tetrafluorooctane hexafluoropropylene), or polyvinylidene fluoride is used. A substrate composed of a porous film made of a thermoplastic resin such as a fluorine resin such as ethylene is preferred. Moreover, the thickness of the hydrocarbon-based anion exchange membrane is preferably from 5 to 200 μm, from the viewpoint of suppressing the electric resistance to be low and imparting mechanical strength necessary for the support film. It is preferred to have a thickness of 8 to 150 μm.

In the present invention, the quaternization and crosslinking reaction of the catalyst electrode precursor layer formed on the precursor of the anion exchange membrane is performed in conjunction with the gas diffusion described above. It is preferred to carry out the quaternization of the catalyst electrode precursor layer formed on the layer or the anion exchange membrane under the same conditions as the crosslinking reaction.

(membrane-electrode assembly)

The membrane-electrode assembly in which the catalyst electrode layer and the anion exchange membrane are laminated in the present invention can be suitably used in an anion exchange membrane type fuel cell and a water electrolysis apparatus. As described above, the membrane-electrode assembly of the present invention can be applied to a precursor of an anion exchange membrane or an anion exchange membrane by using a composition for forming a catalyst electrode layer containing an ion conductivity imparting agent precursor and a catalyst. The material is dried to form a catalyst electrode precursor layer, and is obtained by contacting the diamine compound to carry out quaternization and crosslinking reaction.

Further, the gas diffusion electrode in which the catalyst electrode layer of the present invention and the gas diffusion layer are laminated can be suitably used in an anion exchange membrane type fuel cell and a water electrolysis apparatus. As described above, the gas diffusion electrode of the present invention can be applied to a gas diffusion layer by applying a composition for forming a catalyst electrode layer containing an ion conductivity imparting agent precursor and a catalyst, and drying to form a catalyst electrode precursor layer. Further, it is obtained by bringing it into contact with a diamine compound to carry out a quaternization reaction and a crosslinking reaction.

(anion exchange membrane type fuel cell)

When the gas diffusion electrode or the membrane-electrode assembly described above is used, for example, an anion exchange membrane type fuel cell can be assembled by using the configuration shown in Fig. 1 . That is, when the catalyst electrode layer is formed on the gas diffusion layer, two sheets are used and the anion exchange membrane is sandwiched on the side where the catalyst electrode layer is formed. Thereby, the state in which the combination of FIG. 1 has 4, 5, 6, 7, and 8 can be realized. Alternatively, the catalyst electrode layer precursor is directly formed on both surfaces of the anion exchange membrane or its precursor, and after crosslinking and quaternization, when used as a catalyst electrode layer, it can be directly used as a fuel cell. also, A fuel cell can be configured by superposing a support (carbon porous film) functioning as a gas diffusion layer on the catalyst electrode layer to improve gas diffusibility.

In the anion exchange membrane type fuel cell described above, when hydrogen is used as the fuel, the humidified hydrogen gas is supplied to the fuel chamber side, and the humidified oxygen or air is supplied to the oxidant chamber side to generate electricity.

In the anion exchange membrane type fuel cell of the present invention, the ion conductivity can be improved by increasing the heat resistance of the anion exchange group and preventing the ion conductivity imparting agent from eluting from the catalyst electrode layer due to the increase in the operating temperature. It is maintained at a high level, so the fuel cell can continue to maintain good power generation performance for a long period of time.

(water electrolysis device)

Further, when the gas diffusion electrode or the membrane-electrode assembly is used, a water electrolysis device can be assembled. In other words, when the catalyst electrode layer is formed on the gas diffusion layer and crosslinked and quaternized, when the gas diffusion electrode is used as a gas diffusion electrode, the gas diffusion electrode can be used to sandwich both sides of the anion exchange membrane. Water electrolysis device. Alternatively, the catalyst electrode layer precursor is directly formed on both surfaces of the anion exchange membrane or its precursor, and after cross-linking and quaternization, when used as a catalyst electrode layer, it can be directly used as a water electrolysis device. In addition, a water-based electrolysis device can be configured by superposing a support (carbon porous body or metal porous body) functioning as a gas diffusion layer on the catalyst electrode layer to improve gas diffusibility.

A schematic configuration example of such a water electrolysis apparatus is shown in Fig. 2, but the water electrolysis apparatus of the present invention is not limited by the structure of Fig. 2. In Fig. 2, an example of a water electrolysis device 20 using an anion exchange membrane 8 is shown. in The anode-side catalyst electrode layer 11 is provided on one surface of the anion exchange membrane 8, and the anode-side catalyst electrode layer 12 is provided on the other side. A gas diffusion layer may be provided on the surface of each of the catalyst electrode layers, which is omitted in the figure. At least one of the cathode side catalyst electrode layer 11 and the anode side catalyst electrode layer 12 may be the catalyst electrode layer of the present invention, and both of them are preferably formed as the catalyst electrode layer of the present invention. Each of the catalyst electrode layers is connected to the external power source 30 via the wires 31 and 32, respectively. The electrolytic cell is provided with raw water supply pipes 13 and 14 for supplying raw water. As the raw water, a dilute aqueous alkali solution can be suitably used from the viewpoint of electrolytic efficiency, and for example, a thin aqueous solution of KOH can be used. The water starts to be electrolyzed by supplying raw water and energizing from an external power source. The reaction on the cathode side and the anode side is as follows.

(Cathode side) 2H ₂ O+2e ^- →H ₂ +2OH ^-

(anode side) 2OH ^- → 1/2O ₂ + H ₂ O + 2e-

Hydrogen and hydroxide ions are generated by electrolysis on the cathode side. The hydroxide ions pass through the laminated ion exchange membrane 8 to reach the anode side and generate oxygen, water, and electrons. The hydrogen generated on the cathode side is recovered through the gas recovery pipe 15, and the oxygen generated on the anode side is recovered through the gas recovery pipe 16.

In the water electrolysis apparatus of the present invention, the heat resistance of the anion exchange group is improved, and the high-temperature ion conductivity imparting agent accompanying the operating temperature is prevented from being eluted from the catalyst electrode layer, and the ion conductivity can be maintained high. Therefore, it is possible to continue the operation for a long period of time with a high electrolysis efficiency.

Example

Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited by the examples. Moreover, it is shown in the examples and comparative examples. The characteristics of the anion exchanger and the fuel cell are values measured by the following methods.

(Ion exchange capacity of anion exchanger)

A cast film (cast film) was cast on a container made of polytetrafluoroethylene by dissolving a solution of a styrene-based ion exchanger precursor before the cross-linking reaction (concentration: 5.0% by mass, solution amount: 2.5 g). ). The cast film is reacted with a solution containing a diamine to introduce an ion exchange group. The cast film of the obtained anion exchanger was sufficiently washed with ion-exchanged water, and then placed in a visking tube together with ion-exchanged water, and both ends were wrapped. Further, the dialysis tube was made of cellulose, and the molecular weight cut off was 8,000, and the mass (Dv (g)) after drying at 50 ° C for 3 hours under reduced pressure was measured in advance. The dialysis tube containing the cast film was immersed in a 0.5 mol/L-HCl aqueous solution (50 mL) for 30 minutes, and this operation was repeated three times to make the cast film therein into a chloride ion type. Further, it was washed with ion-exchanged water (50 mL) for 10 minutes (10 times). This was immersed in a 0.2 mol/L-NaNO ₃ aqueous solution (50 mL) for 30 minutes or more to be substituted into a nitrate ion type, and the free chloride ions were extracted (4 times). Further, the ion-exchanged water (50 mL) was immersed for 30 minutes or more and the extracted chloride ions were recovered (2 times). The solution obtained by extracting the chloride ions was concentrated, and the amount of silver nitrate aqueous solution was measured by a potentiometric titration apparatus (COMTITE-900, manufactured by Hiranuma Sangyo Co., Ltd.) to quantify (A mol). Next, the titrated membrane was immersed in a 0.5 mol/L-NaCl aqueous solution (50 g) for 30 minutes or more (three times), and dialysis was sufficiently performed using ion-exchanged water until the chloride ions could not be detected in the washing liquid, and then The tube was taken out, and the inside of the tube was removed by a dryer at 50 ° C for 15 hours, and then dried under reduced pressure at 50 ° C for 3 hours, and the mass (Dt (g)) was measured. Based on the above measured values, the ion exchange capacity was determined according to the following formula.

Ion exchange capacity = A × 1000 / (Dt - Dv) [mmol / g - dry quality]

(Method for determining the content rate of a structural unit having a crosslinked structure represented by formula (1) in an anion exchanger)

First, when crosslinking and quaternization are carried out using a diamine compound, the amount of the structural unit represented by the formula (1) contained in the anion exchanger can be quantified by solid NMR.

From the ¹ H-NMR spectrum obtained from the cast film produced using only the diamine compound, the peak area of the structural unit represented by the formula (1) and the peak area of the structural unit represented by the formula (3) were obtained, and the formula (4) was obtained. The ratio of the peak areas of the structural units to be expressed, and the content ratio of the formula (1) was calculated from the existence ratio of each structural unit. The content ratio of the obtained formula (1) is shown in Table 1.

When the diamine compound is used in combination with the tertiary amine, the amount of the tertiary amine contained in the third-order amine having a ¹³ C isotope in the molecule can be quantified by ¹³ C-NMR spectroscopy.

The peak area of the ¹³ C-NMR spectrum of trimethylamine obtained from a cast film produced using only trimethylamine ( ¹³ C isotope) was set to 1, and a mixture of a diamine compound and trimethylamine mixed in an arbitrary ratio was used. The cast film obtained by cross-linking and quaternizing the liquid was subjected to ¹³ C-NMR spectroscopy to determine the ratio of the peak area to the peak area of trimethylamine as P, and the degree of cross-linking was calculated to be 1-P (because The ¹³ C derived from other carbon atoms is a trace amount, and is set to 0) here. Based on the obtained degree of crosslinking, the content ratio of the formula (1) was determined in accordance with the following.

Content ratio = degree of crosslinking × molecular weight of formula (1) / [degree of crosslinking × molecular weight of formula (1) + P × molecular weight of formula (2)]

The content ratio of the structure of the obtained formula (1) is shown together in Table 1.

(heat resistance of anion exchanger)

Two anion exchangers in which the counter ions were made into a hydroxide ion type were prepared, and they were placed in a container made of polytetrafluoroethylene, and each was kept in ion-exchanged water for 500 hours in an oven at 50 ° C or 90 ° C. The respective anion exchange capacities were determined. The anion exchange capacity retention ratio was determined from the ratio of the anion exchange capacity of the anion exchanger after the treatment to the anion exchange capacity of the anion exchanger before the treatment, and the heat resistance of the anion exchange group was evaluated.

(Method for measuring moisture content of anion exchanger)

A casting film having a film thickness of about 50 to 70 μm produced by the same method as described above is attached to a measuring device having a constant temperature and humidity chamber equipped with a magnetic floating type balance scale (manufactured by BEL Corporation, Japan, "MSB-AD- V-FC"). First, the film quality (Ddry (g)) after drying at 50 ° C for 3 hours under reduced pressure was measured. Next, the temperature of the constant temperature bath was set to 40 ° C, the relative humidity in the tank was maintained at 90%, and the film quality (D (g)) was measured at the time when the mass change of the film was 0.02% / 60 seconds or less. Based on the above measured values, the water content was determined according to the following formula.

Moisture content of 90% relative humidity = ((D-Ddry) / Ddry) × 100 [%]

(Method for measuring solubility in water)

10 g of the anion exchanger was immersed in 100 ml of ion-exchanged water at 80 ° C for 1 hour while stirring using a magnetic stirrer, and the undissolved anion exchanger was removed from the ion-exchanged water by filtration under reduced pressure. The residual ion-exchanged water was added to the eggplant type flask and concentrated under reduced pressure, and then vacuum-dried at 50 ° C for 3 hours, and the weight of the residue was measured. Based on the above measured values, the anion exchange body solution is calculated. When the weight % of water was dissolved, and the value was 0.5% by weight or less, the water resistance was evaluated to be good.

(Assembling method of fuel cell unit)

When the catalyst electrode layer is formed on the gas diffusion layer and the gas diffusion electrode is formed, the gas diffusion electrode which is 23 mm square (about 5 cm ² ) is cut, and the catalyst electrode layer of the gas diffusion electrode is contacted. One piece of each side of the ion exchange membrane (anion exchange capacity: 1.8 mmol/g-dry mass, water content at 25 ° C of 25% by mass, dry film thickness of 28 μm, and outer dimension of 40 mm) was placed in the first place. The figure shows the fuel cell unit. Further, when the catalyst electrode layer is formed on the ion exchange membrane or its precursor, that is, when the membrane-electrode assembly is formed, ^two gas diffusion layers (TORAY) which are cut into 23 mm square (about 5 cm ² ) are used. HGP-H-060, manufactured by the company, having a thickness of 200 μm, was laminated on each of the catalyst electrode layers on both surfaces of the membrane-electrode assembly, and incorporated into the fuel cell unit shown in Fig. 1.

(Power generation endurance test method)

100 ml/min of hydrogen gas humidified to 90% RH with respect to the unit temperature was used as the fuel gas, and 200 ml/min of air humidified to 90% RH with respect to the unit temperature was supplied as an oxidant gas to the fuel cell unit. The temperature of the fuel cell unit was set to 50 ° C or 90 ° C. The cell voltage value (V) at a current of 500 mA ‧ cm ^-2 was taken out from the cell. Further, the voltage value after 100 hours in this state was measured.

Example 1

30 g of bromobutylstyrene was subjected to radical polymerization by 2,2' azobisisobutyronitrile in a toluene solvent to obtain polybromobutylstyrene (quantitative average molecular weight) 80,000). A cast film of the obtained polybromobutylstyrene was produced and immersed in 50 g of a diamine compound (N, N, N', N'-tetramethyl-1,6-hexanediamine). After 24 hours, it was taken out, and the cast film of the anion exchanger was obtained by washing.

Table 1 shows the content ratio of the structural unit having the crosslinked structure represented by the formula (1), the solubility test result, the heat resistance test result, the ion exchange capacity, and the water content of the cast film of the obtained anion exchanger.

Next, polybromobutylstyrene was dissolved in ethyl acetate to prepare a 5 wt% solution. 1 g of a catalyst (in the case of a platinum particle having a particle diameter of 30 to 50 nm and having a particle diameter of 2 to 10 nm in a primary particle diameter of 30 to 50 nm) was added and dispersed in 2 g of the solution to prepare a catalyst electrode layer-forming composition. This was applied to a gas diffusion layer (carbon paper made of SGL CARBON Co., Ltd., GDL25BC, thickness: 190 μm) in a size of 23 mm square (about 5 cm ² ) and white gold was 0.5 mg ‧ cm ^-2 , and then dried. A catalyst electrode precursor layer is obtained on the gas diffusion layer. The catalyst electrode precursor layer was immersed in 20 g of a diamine compound (N,N,N',N'-tetramethyl-1,6-hexanediamine). After 24 hours, it was taken out and washed to obtain a gas diffusion electrode. The obtained gas diffusion electrode was immersed in a 1 mol/L aqueous solution of potassium hydrogencarbonate for 15 minutes, and the immersion was repeated 5 times to cause relative ion exchange to become hydrogencarbonate ions, and after washing with ion-exchanged water, at room temperature. It was allowed to dry for 24 hours. At the gas diffusion electrode after drying, the thickness of the catalyst electrode layer was 5 μm. A power generation endurance test was performed using the obtained gas diffusion electrode. The results are shown in Table 2.

Example 2

In addition to a 2:8 mixed molar ratio solution of trimethylamine and N,N,N',N'-tetramethyl-1,6-hexanediamine as a reagent for the quaternization and cross-linking reaction, The same operation as in Example 1 was carried out to prepare a cast film and gas of an anion exchanger. Body diffusion electrode. The content ratio, the solubility test result, the ion exchange capacity, and the water content of the structural unit having the crosslinked structure represented by the formula (1) of the cast film of the obtained anion exchanger are shown in Table 1. Further, a power generation endurance test was carried out using the obtained gas diffusion electrode. The results are shown in Table 2.

Example 3

The cast film of the anion exchanger and the gas diffusion electrode were prepared in the same manner as in Example 1 except that polybromopropylstyrene was used instead of polybromobutylstyrene. The content ratio, the solubility test result, the ion exchange capacity, and the water content of the structural unit having the crosslinked structure represented by the formula (1) of the cast film of the obtained anion exchanger are shown in Table 1. Further, a power generation endurance test was carried out using the obtained gas diffusion electrode. The results are shown in Table 2.

Comparative example 1

A cast film and a gas diffusion electrode of an anion exchanger were prepared in the same manner as in Example 1 except that commercially available polychloromethylstyrene (number average molecular weight: 55,000) was used instead of polybromobutylstyrene. The solubility test results, ion exchange capacity, and water content of the cast film of the obtained anion exchanger are shown in Table 1. Further, a power generation endurance test was carried out using the obtained gas diffusion electrode. The results are shown in Table 2.

Comparative example 2

A cast film and a gas diffusion electrode of an anion exchanger were prepared in the same manner as in Example 2 except that commercially available polychloromethylstyrene was used instead of polybromobutylstyrene. The solubility test results, the heat resistance test results, the ion exchange capacity, and the water content of the cast film of the obtained anion exchanger are shown in Table 1. Moreover, the power generation endurance test is performed using the obtained gas diffusion electrode Test. The results are shown in Table 2.

Comparative example 3

To 98.25 parts by weight of bromobutylstyrene, 1.75 parts by weight of diethylbenzene (purity: 57%) and 1.0 part by weight of azobisisobutyronitrile were added, and crosslinking was carried out by maintaining at 70 ° C for 24 hours under a nitrogen atmosphere. polymer. Suspending the obtained crosslinked polymer in two In the alkane, trimethylamine equivalent to 3 molar equivalents of bromo group was dropped, and the suspension was reacted at 50 ° C for 10 hours. The obtained quaternized crosslinked polymer was sufficiently washed with ion-exchanged water. The solubility test results, the heat resistance test results, the ion exchange capacity measurement, and the water content of the quaternized crosslinked polymer obtained by the measurement were measured. The results are shown in Table 1. Moreover, the obtained quaternized crosslinked polymer and the Pt/C catalyst were dispersed in a propanol solvent to prepare a catalyst electrode layer-forming composition. After it was coated on the gas diffusion layer, it was dried to obtain a gas diffusion electrode. A power generation endurance test was performed using the obtained gas diffusion electrode. The results are shown in Table 2.

Comparative example 4

The same procedure as in Comparative Example 3 was carried out except that 17.5 parts by weight of diethylbenzene (purity: 57%) and 1.0 part by weight of azobisisobutyronitrile were added to 82.5 parts by weight of bromobutylstyrene to prepare a crosslinked polymer. The operation is to modulate a quaternized crosslinked polymer and a gas diffusion electrode. The solubility test results, the heat resistance test results, the ion exchange capacity, and the water content of the obtained quaternized crosslinked polymer are shown in Table 1. Further, a power generation endurance test was carried out using the obtained gas diffusion electrode. Display the results in Table 2

Further, the degree of crosslinking of divinylbenzene in the table means the proportion (% by weight) of divinylbenzene which accounts for the total monomer weight in the preparation stage.

From the results of the first to third embodiments, the following items can be confirmed.

First, it is confirmed that a styrene-based polymer obtained by extending an alkyl chain length between an ion-exchange group and an aromatic ring can be quaternized and crosslinked in a solution containing a diamine compound to form a touch. The dielectric electrode layer contains an ion conductivity imparting agent having a crosslinked structure in which a diamine compound is crosslinked, and excellent fuel cell output characteristics can be obtained.

In Comparative Example 1, when polystyrene having a short chain length of an alkyl group between an ion exchange group and an aromatic ring was used, it was found from the results of ion exchange capacity and water content that crosslinking by a diamine compound was observed. The quaternization is almost unaltered and shows very hydrophobic and lower ion conductivity. As a result, the fuel cell output power characteristics are extremely limited. Moreover, as a result of evaluation of the physical properties of the cast film, the dispersion state of the ion conductivity imparting agent precursor in the catalyst electrode layer is inferior, and when the ion conductivity imparting agent precursor is solidified, it means that the crosslinking reaction does not occur. Conduction does not occur and ion conductivity is not exhibited. The results of the first embodiment and the comparative example 1 are the styrene-based polymers obtained by extending the alkyl chain length between the ion-exchange group and the aromatic ring, and the resin dispersibility is poor even when the catalyst electrode layer is produced. It also has sufficient ion conductivity to exhibit good battery characteristics. Further, in Comparative Example 1, since the alkyl chain length between the ion exchange group and the aromatic ring was short, the heat resistance of the ion exchanger was low, and the operating temperature was 50 ° C compared to the operating temperature of the fuel cell. The power generation durability at 90 ° C is low.

In Comparative Example 2, when polystyrene having a short chain length of an alkyl group between an ion exchange group and an aromatic ring is used, by using a tertiary amine and a diamine compound in combination, the quaternary system is crosslinked to some extent. The heat resistance and power generation test results of the anion exchanger at 50 ° C were relatively good. But because of the ion exchange group and the aromatic ring Since the alkyl chain length is short, the heat resistance of the anion exchanger at 90 ° C and the power generation test result are low.

In Comparative Example 3 and 4, when crosslinking was not carried out at the crosslinking site, in Comparative Example 3 in which the degree of crosslinking was low, the solubility of the ion conductivity imparting agent in water increased, and ion conductivity was imparted. The dissolution of the agent causes the performance of the catalyst electrode layer to be low, and the fuel cell output power characteristics are limited. In Comparative Example 4, when the degree of crosslinking is increased, the solubility of the ion conductivity imparting agent in water can be improved, but the ion conductivity is lowered due to the elevated crosslinking ratio, and the performance of the catalyst electrode layer is lowered, and the initial stage of power generation is lowered. The voltage value is low and the fuel cell output power characteristics are limited. Further, in the durability test of the anion exchanger, good results were obtained even at 90 ° C. However, since the voltage was lowered after 100 hours in the power generation test at 90 ° C, it was immersed in water by The effect of high heat resistance can be obtained by extending the alkyl chain length between the exchange group and the aromatic ring. However, under the power generation condition, drying is carried out by adding a hydrophobic cross-linking site, and it is confirmed that the thermal decomposition reaction is promoted.

When the catalyst electrode layer is formed using the anion exchanger of the present invention, it has high heat resistance, and by introducing a crosslinked structure and imparting ion exchange ability by using a diamine compound, excellent catalyst electrode layer performance and excellent properties can be obtained. Fuel cell output power characteristics.

Claims (8)

An anion exchanger comprising a structural unit having a crosslinked structure represented by the following formula (1), (wherein a is an integer from 3 to 10, b is an integer from 2 to 8, and R ¹ , R ² , R ³ and R ⁴ are each independently selected from methyl or ethyl, and X ^- is selected from OH ^- , One or more relative ions of the group consisting of HCO ₃ ^- , CO ₃ ^2- , Cl ^- , Br ^- , and I ^- ). The anion exchanger according to claim 1, wherein the content of the structural unit represented by the formula (1) is 70% by mass or more. An ion conductivity imparting agent comprising the anion exchanger according to item 2 of the patent application. A catalyst electrode layer containing the ion conductivity imparting agent and the electrode catalyst according to claim 3 of the patent application. A membrane-electrode assembly comprising the catalyst electrode layer as described in claim 4 of the patent application. An anion exchange membrane type fuel cell, which is included in the fifth patent application scope The membrane-electrode assembly described in the above paragraph. A water electrolysis device comprising the membrane-electrode assembly according to claim 5 of the patent application. A method for producing a catalyst electrode layer, comprising: a composition for forming a catalyst electrode layer containing a styrene polymer having an alkyl halide and an electrode catalyst in an aromatic ring, and a gas diffusion layer and anion exchange After the film or the precursor of the anion exchange membrane is dried to form a catalyst electrode precursor layer, the styrene polymer having a halogenated alkyl group in the aromatic ring is subjected to quaternization by contacting the diamine compound. The crosslinking reaction is carried out to form a catalyst electrode layer as described in claim 4 of the patent application.