JPS6167788A - Production of joined body of ion exchange resin film and electrode - Google Patents

Abstract

PURPOSE:To obtain a joined body having superior electrochemical characteristics by forming an electrode made of a mixture of catalyst powder for an electrode with powder of a specified ion exchange resin and a specified binder by a specified method and by joining the formed electrode to a membrane of an ion exchange resin. CONSTITUTION:Catalyst powder for an electrode is impregnated with a soln. prepd. by dissolving an ion exchange resin contg. perfluorocarbon resin as the base in an org. solvent or a mixed solvent consisting of an org. solvent and water, and the solvent is evaporated to form catalyst powder for an electrode supporting said ion exchange resin. This catalyst powder is mixed with a fluororesin binder, and the mixture is bonded to one side or both sides of a membrane of an ion exchange resin contg. perfluorocarbon resin as the base by heating under pressure to obtain the desired joined body.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing an ion exchange resin membrane-electrode assembly. More specifically, the present invention provides
Batteries, water electrolyzer 9 salt electrolyzer, hydrochloric acid electrolyzer, electrochemical enzyme component 1111 equipment, electrochemical hydrogen valve 1 int equipment
? 1. This invention relates to a method for manufacturing an ion exchange resin membrane-electrode assembly used in various electrochemical devices such as a water electrolysis type humidity lens IL-.

Conventional technology, ion exchange resin llφ is used as a solid-state electrode IW! 1 and 4'
) with an electrode integrally bonded to the electrochemical device and 1 fuel + 1 battery (for example, American 4J revision 3134697
), water electrolyzer (e.g. J, S, Bone, p
roceerlings of14th Δnl'1
llal pOWer 3011rCeS C0
nf(!renCe.

p62~G4 (1060)), halide electrolytic cell (e.g. Eva Q?r Ittl In 54-10749
3 father-in-law), 7fJ4 vapor chemical oxygen molecule Ii1 device (
For example, Tokuko Showa 43-250+'li month, or Tokuko Showa 5G -33979%), electrochemical water moisture It!
It loading <e.g. 5janlQl/I”, l-a
nger and RObCrj G, l-1alr
, IeInan, 3C! 0ITCO, Vol 14
2. NO, 3587 (19G3)) OJ: Water electrolysis type humidity sensor (for example, Hiroyasu Takenaka).

Ei Shimakubi-9 Teiji Kawago, Sensor Technology, \101.4 No.
.

5 (1'1184)) etc. have been proposed.

-Ion exchange resin membranes used to have a core of styrene-divinylbenzene resin, which was used for ion exchange);↓
However, near (1), sulfur A based on perfluorocarbon resin was used.
acid group, carbon M j ;! H Rui 1. The perfluorocarbon resin with J1 as an ion exchange group is
It has become commonly used because it is more erroneous. As for the ion exchanger, a hydrogen type is used in a fuel cell or a water electrolyzer, and a type of ion exchanger is used in a 1g electrolyzer.

As a method for integrally bonding an electrode to an ion exchange resin membrane, a method of heat-pressing a mixture of an electrode catalyst powder and a fluororesin as a binder to an ion exchange resin membrane (for example, U.S. Pat. 15544) and a method of electroless plating of an electrode catalyst metal onto an ion exchange resin membrane (for example, JP-A-55-38934).

Electrochemical devices are classified according to the type of electrochemical device, but can be broadly classified into gas diffusion electrodes and gas generation electrodes.In the case of gas diffusion electrodes, the reaction gas is supplied to the electrode , in the case of a gas-generating electrode (,11, gas is generated from the electrode by an electrolytic reaction.

Gas diffusion electrode (,↓fuel r1 battery, electrochemical oxygen content I4
The cathode of 11 units, the anode of the electrochemical hydrogen molecule 1ill device, and the 1 (electrode) of the halide electrolytic cell when R element is used as the cathode depolarizer.The gas generating electrode is used for the water electrolytic cell, electric It is used as an anode of a chemical oxygen branch JT wave device, a cathode of an electrochemical hydrogen valve 1111f device, an anode of a halide electrolytic cell, etc.

In general, among the methods of integrally bonding the electrode 4 (i) to the ion exchange resin membrane of the upper jbo, the heat pressure bonding method is the gas diffusion electrode 11!
1 (Although it can be applied to both 13Jz and gas generating electrodes, electroless plating can only be applied to gas generating electrodes. This is because in the case of gas generating electrodes, it does not matter if the reaction site of the electrode gets wet with water. However, in the case of gas diffusion electrodes, the reaction cannot proceed successfully unless there are parts that get wet with water and parts that don't get wet with water. The aqueous nature of the fluororesin effectively contributes to the gas diffusion electrode reaction.

Electrochemical reactions occur at any interface between electrodes and electrolytes, and the current-voltage characteristics of electrochemical reactions at these interfaces are greatly influenced by the contact area between the electrodes and electrolyte. Generally speaking, a lifting platform where the electrolyte is a solution has a large contact surface between the electrode and the electrolyte, whereas when the electrolyte is an ion exchange resin or a solid electrolyte, the contact surface between the electrode and the electrolyte is large. Area is relatively small. One way to overcome this problem is to insert an electrode catalyst powder and an ion exchange resin powder between an ion exchange resin membrane as a solid electrolyte and an electrode, as described in, for example, No. 145-14220. There is a method of increasing the contact area between the IJ1A iomimetic resin 1F) and the electrode by interposing a layer of mixture with a binder. With such a structure, a layer of mixture of ion exchange resin powder and calcining agent, which acts as both an electrode and an electrolyte, Part of the electrode and l
] It can also be understood as This is because an electrode layer not containing an ion exchange resin adjacent to this mixture layer is not necessarily required.

Problems to be Solved by the Invention How to increase the bonding area between the ion exchange resin membrane and the electrode described in the above-mentioned IIU45-14220? 4. Fuki's way of thinking is extremely effective.

However, there was a problem with the 1'+1 employed here, and there was a limit to the performance of the electrochemical device using the ion exchange resin Ilψ in conjunction with the electrode. In other words, in the above literature, sulfone Ht3 is used as the ion exchange resin membrane material O)1.
．． Since a Ht-introduced non-divinylbenzene copolymer is used, there are problems with heat resistance and chemical stability. 7. - A non-divinyl benzene polymer for sulfonic acid oxide is used as the ion exchange resin powder in the mixture layer of the electrode catalyst powder, ion exchange resin powder, and binder, but this material is also used. Again, it has 11 points for heat resistance and chemical stability. especially,
The anode using this material has the same durability (oxidation resistance). Also, the particle size of the powder is 200
Since it is made of methacrylate, there are not many points of contact between the electrode catalyst powder and the electrolyte.Also, the 1-lyethylene solution of polystyrene as a binder has insufficient aqueous properties, and the electrode Since the surface of the catalyst and the surface of the ion exchange resin layer 6 are coated in a membrane, it is difficult to expect a substantial increase in the contact area between the electrode catalyst powder and the ion exchange resin powder.

Means for Solving the Problems The present invention impregnates an electrode catalyst powder with an organic solvent solution of an ion exchange resin based on perfluorocarbon resin or a mixed solvent solution of an organic solvent and water, and evaporates the solvent. , electrode touch! I! I! First, a powder with an ion exchange resin dispersed and supported on the surface is prepared, and a mixture of the electrode catalyst powder supporting the ion exchange resin and a fluororesin binder is mixed into an ion exchange resin membrane based on perfluorocarbon resin. The above-mentioned problems are solved by forming electrodes on an ion exchange resin membrane by heat-pressing on one or both sides.

Function The greatest feature of the present invention is that the starting material of the ion exchange resin mixed into the electrode is either an organic solvent solution of the ion exchange resin based on perfluorocarbon resin or a mixture of an organic solvent and water. The point is that a mixed solvent solution is used.

A typical ion exchange resin based on perfluorocarbon resin is perfluorocarbon sulfonic acid resin. The affinity of perfluorinated lJ-bonsulfonic acid resin with solvents varies depending on the number of moles of sulfuric acid L, and this ion-exchange resin has a large exchange capacity with lower aliphatic alcohols, such as n - It is known to dissolve in butanol and other highly polar organic solvents (Japanese Patent Publication No. 18-13333).

Such an ion exchange resin solution can be obtained from Nafion solution (NΔFrO
It is sold under the name N3o1ution).

The Nafion solution is manufactured by American company Decobon (DLI Pont).
5% of perfluorocarbon sulfonic acid resin under the trademark NΔFION sold by )
It is a lower aliphatic alcohol (containing 10% water) solution.

When an electrode catalyst powder and an ion exchange resin solution such as Nafion solution are mixed and the solvent is evaporated, the ion exchange resin is very finely dispersed on the surface of the electrode catalyst powder.
held. In other words, by adopting such a method,
The contact area between the electrode catalyst and the ion exchange resin becomes much larger than when the powdered ion exchange resin and the electrode catalyst powder are mixed.

In addition, ion exchange resins based on perfluorocarbon resins have better heat resistance, chemical stability, P1 durability, and better durability than ion exchange resins based on styrene-divinylbenzene copolymers as described above. It is far superior in oxidation properties.

As the ion exchange group of the ion exchange resin of the ion exchange resin solution, a sulfonic acid group, a carboxylic acid group, or a mixture of both can be used. In addition, the mobile ion of the ion exchange group is the pro-1 hene type.

Sodium ion type, potassium ion type 1! etc., depending on the target electrochemical VC configuration.

Further, the replacement of protons with other ions may be performed after the electrode is bonded to the ion exchange resin membrane.

All conventionally known electrode catalyst powders can be used.

Examples of fluororesin binders include polytetrafluoroethylene,
One or a mixture of tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and polytrifluoroethylene chloride may be used. j: These fluororesins are in powder form.

An aqueous suspension or an organic solvent suspension is used. It is also effective to use a suspension of fluororesin mixed and dispersed with powdered fluororesin.

The ion exchange resin membrane material contains sulfonic acid groups. A perfluorocarbon resin having a carboxylic acid group or a mixture thereof as an ion exchange group is preferable.

The ion to be transferred may be appropriately selected from proton type, sodium ion type, potassium ion type, etc. depending on the electrochemical device used.

As a method for joining the electrode to the ion exchange resin membrane, the method of -10=weighing can be applied. The first method is to prepare a soda membrane sheet F~ from a mixture of an electrode catalyst powder supporting an ion exchange resin and a fluororesin binder, and heat and press it onto an ion exchange resin membrane. The method is to support an ion exchange resin and blow a mixed dispersion of an electrode catalyst powder and a fluororesin binder in the form of a suspension onto an ion exchange resin membrane (after volatilizing the IQ medium, The third method is to screen print the mixed dispersion of (a) above on an ion exchange resin membrane and heat press. However, the present invention is not limited to these methods.

In any case, since the ion exchange resin and binder used in the present invention are all fluorine-containing polymers, they not only have excellent heat resistance, chemical stability, and anodic oxidation resistance, but also have excellent resistance to electrodes. The bonding strength between each of the contained materials and between the electrode and the ion exchange resin membrane is extremely high.

The method for producing an ion exchange resin membrane-electrode assembly of the present invention may be applied to both the cathode side and the anode side, or only to one side. That is, a conventional electrode not containing an ion exchange resin may be bonded to either the cathode or the anode.

In order to prevent wetting by water, a porous fluororesin layer or a metal not necessarily related to catalytic activity is provided on the back side of the electrode formed by the method of the present invention.

Forming a porous mixed layer of powder of metal oxide, carbon, etc. and fluororesin may also be effective fJ.

Example 1 A rhodium electrode was bonded to one side of Nafion 117, a perfluorocarbon sulfur resin made by Decobon, USA, by electroless plating. The amount of rhodium supported was 4 mg/+ffl.

On the other hand, 20 g of a 5% Nafion solution (manufactured by Aldrich Chemical 1, USA, a mixed solvent solution of perfluorocarbon sulfonic acid resin with lower aliphatic alcohol and water) was added to 10 g of platinum black powder as an electrode catalyst powder. After thorough mixing, the platinum black powder was taken out, and the adhering solvent was volatilized by vacuum drying. In this way, a platinum black powder capable of supporting a perfluorocarbon sulfonic acid resin is obtained.

Next, 4 ml of a 60% polytetrafluoroethylene aqueous suspension was added to 10 q of this platinum black powder with an exchange resin, mixed thoroughly, and then 1 ml of aretone was added and the agglomerated mixture was rolled. An electrode sheet with a thickness of 0.2 mm was manufactured.

Next, this electrode sheet was hot-pressed at a temperature of 100° C. and a pressure of 200 K (1/F) on the surface of the ion exchange resin membrane to which the rhodium electrode was bonded, to which the rhodium electrode was not bonded.

The 1q ion exchange resin membrane-electrode assembly thus becomes the 414 component of an electrochemical oxygen separation device.

? +- In other words, the rhodium electrode of this bonded body is used as an anode,
When an electrode containing platinum black and perfluorocarbon sulfonic acid resin is used as a cathode, air is supplied to the cathode side, water is supplied to the anode side, and a direct current is applied to both electrodes, pure oxygen is generated at the anode side. , a gas from which oxygen has been removed from air is obtained on the cathode side.

2. In Example 1, the anode side was also the same electrode as the cathode side.

Effect of invention Example 1 is 1! The ion-exchange resin membrane-electrode assembly obtained in Example 1 was prepared using platinum black and sulfone oxide styrene-divinylbenzene resin powder (particle size 5).
4 micron) and fluororesin to form a garlic electrode is designated as B, and in Example 1, platinum black and polytetrafluoroethylene were used without mixing any ion exchange resin into the cathode. The bonded body with electrodes formed is C
When the current density-lightning pressure characteristics ↑4 of each electrochemical oxygen separation device were compared, the results shown in FIG. 1 were obtained.

That is, it is clear that excellent characteristics are exhibited in the order of Δ>B>C. , B is better than C, special 1/l
This is because when an ion exchange resin is mixed into the cathode, the number of contact points between the electrode and the electrolyte increases, and the effective area of the in-electrode increases accordingly.

The reason why A has better properties than B is due to the difference in the ion exchange phase and fat mixed into the cathode.

In case of B, relatively large particles of ion exchange resin powder are used, so platinum black does not come into contact with the ion exchange resin powder very often.
In this case, the ion exchange resin is in contact with the platinum black in a much finer form (1), so the contact area between the two is larger.

Next, the ion-exchange resin membrane-electrode assembly obtained in Example 2 was treated with D, and in Example 2, a powder of sulfonated styrene-divinylbenzene resin was used as in the case of 8 above. When we assembled the combined bodies into an electrochemical oxygen separator and conducted a life test at a current density of 200 mA/aδ, we found that the relationship between operating time and voltage was 1q as shown in Figure 2. It was done. Sunawa 1
5. In the case of the product of the present invention, no abnormality was observed, whereas in the case of the conventional product, the voltage decreased over time.

I had upper stomach. This is due to the difference in the anodic oxidation resistance of the ion exchange resins contained in the anode.

As detailed above, the present invention provides excellent electrochemical
(41), and its industrial value is extremely high.

[Brief explanation of the drawing]

FIG. 1 shows an ion-exchanged IBi lipid membrane-electrode assembly obtained according to an embodiment of the present invention using an electrochemical oxygen valve l1111.
This is a comparison of the current density-voltage characteristics when applied to a conventional product. FIG. 2 compares the change in voltage over time when the ion exchange resin membrane-electrode assembly according to one embodiment of the present invention is applied to an electrochemical oxygen valve 11ill installation with that of a conventional product. Δ, D... Inventive product, B, C, F... Conventional crystal shunt
Acupuncture Hi-shu (former company year 4 sale 1j, tr 7 hot method) Showa 60-i "February 8 []

Claims (1)

[Claims] 1. Perfluorocarbon resin obtained by impregnating an electrode catalyst powder with an organic solvent solution of an ion exchange resin based on perfluorocarbon resin or a mixed solvent solution of an organic solvent and water and volatilizing the solvent. An ion exchange resin membrane characterized by being formed by heat-pressing a mixture of an electrode catalyst powder capable of supporting an ion exchange resin and a fluororesin binder onto one or both sides of an ion exchange resin membrane having a perfluorocarbon resin as a base. - A method for manufacturing an electrode assembly.