KR20220074190A - Hydrocarbon-based membrane electrode assemblies using carbon/Nafion blend bonding layers for fuel cells - Google Patents

Abstract

The present invention is a perfluorinated ionomer layer; and a membrane-electrode interface bonding layer comprising a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer, a hydrocarbon-based membrane-electrode assembly using the same, a fuel cell, and a water electrolysis device. The membrane-electrode assembly having an interfacial adhesive layer according to the present invention can overcome the problem of interface detachment during fuel cell operation due to lack of compatibility between the hydrocarbon-based polymer electrolyte membrane and the catalyst layer containing the perfluorine-based ionomer.

Description

A membrane-electrode interface bonding layer comprising a mixture layer of a carbon-based material and a perfluorine-based ionomer, a hydrocarbon-based membrane-electrode assembly and a fuel cell using the same }

The present invention is a perfluorinated ionomer layer; and a membrane-electrode interface bonding layer comprising a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer, a hydrocarbon-based membrane-electrode assembly using the same, and a fuel cell including the same.

Although the increase in energy demand worldwide is increasing day by day, fossil fuels such as petroleum and coal used as main energy sources can only be produced in a limited number of countries and their reserves and production are limited. In addition, due to the disadvantages of the generation of environmental pollutants and the impossibility of regeneration, new eco-friendly energy sources to replace fossil fuels are being studied in various fields.

Among them, polymer electrolyte membrane fuel cell (PEMFC) and polymer electrolyte membrane water electrolysis (PEMWE) are eco-friendly energy source devices using hydrogen, which are attracting the most attention because of their high efficiency and possible miniaturization. . Currently, the electrolyte membrane, which is the core material of PEMFC and PEMWE, is a perfluorinated sulfonic acid polymer electrolyte membrane, which is DuPont's Nafion. It has the advantage of showing proton conductivity).

However, Nafion has disadvantages such as high unit cost and limited use at high temperatures. In order to solve this problem, low-cost hydrocarbon-based membranes have been developed, and among them, sulfonated poly (arylene ether sulfone) copolymers (sulfonated poly ( arylene ether sulfone) copolymer; SPAES) electrolyte membrane. The hydrocarbon-based copolymer having an aromatic structure has thermal stability, excellent mechanical strength and elongation, and low gas cross-mixing capacity between the anode and the cathode.

However, when a membrane-electrode assembly (MEA) is configured with such a hydrocarbon-based electrolyte membrane, electrode transfer is not performed well due to a decrease in compatibility with an electrode catalyst layer containing Nafion, a fluorine-based polymer, as a binder. In addition, even if the membrane-electrode assembly is constituted, the bonding strength is weak, and resistance increases due to delamination between interfaces, or long-term operation is impossible.

The reason for this problem is the chemical and physical difference between the hydrocarbon-based electrolyte membrane and the perfluorine-based ionomer. Hydrocarbon-based electrolyte membranes generally have a higher glass transition temperature (Tg) than perfluorinated ionomers due to their rigid structure containing a benzene ring, which attaches between the electrolyte membrane and the catalyst layer interface when the thermo-compression decal method is used. there is a disability In addition, since there is no chemical compatibility between the two polymers, thermal delamination occurs after the MEA is prepared. This may show the initial performance of the MEA in a short-term state, but the performance is significantly reduced during continuous operation.

As a prior art to solve this problem, Korean Patent Registration No. 10-1894554, in which a bonding layer having a composition gradient of hydrocarbon-based and fluorine-based polymers is applied between the membrane-electrode, three-dimensional using polystyrene particles on the surface of the hydrocarbon-based membrane Advanced Materials 2017, 29, 1603056, which is about a technology for creating an interface structure that is physically interlocked by making a pore structure and introducing an electrode layer thereon, and a fluorine-based polymer and hydrocarbon-based membrane on the surface of a hydrocarbon-based membrane There is Korean Patent Application Laid-Open No. 10-2016-0080779, which is a technology in which a mixture of polymers is applied to the surface as a bonding layer.

Even though the durability of the membrane and the catalyst layer is excellent through these efforts, in most cases, the performance and durability after manufacturing the membrane-electrode assembly (MEA) are deteriorated.

Korean Patent Registration No. 10-1894554. Korean Patent Publication No. 10-2016-0080779.

Advanced Materials 2017, 29, 1603056.

The present invention was developed to solve the above problems, and to overcome the problem of interface detachment during operation of a fuel cell due to lack of compatibility between a hydrocarbon-based polymer electrolyte membrane and a catalyst layer containing a perfluorine-based ionomer. do it with

In addition, it is intended to use a membrane-electrode assembly having such an improved interfacial adhesive layer for a polymer electrolyte fuel cell or a water electrolysis device having the same.

In the present invention, in order to solve the above problems, a perfluorinated ionomer layer; and a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer.

In addition, in the present invention, a hydrocarbon-based polymer electrolyte membrane; a perfluorine-based ionomer layer laminated on the hydrocarbon-based polymer electrolyte membrane; a membrane-electrode interface bonding layer comprising a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer; And it provides a membrane-electrode assembly comprising a catalyst layer laminated on the membrane-electrode interface bonding layer.

In addition, in the present invention, forming a perfluorinated ionomer layer on the substrate; forming a mixture layer of a carbon-based material and a perfluorine-based ionomer on the perfluorine-based ionomer layer to prepare a membrane-electrode interface bonding layer; transferring the membrane-electrode interface bonding layer to a carbon hydrogen-based polymer electrolyte membrane; acid-treating the carbon-hydrogen-based polymer electrolyte membrane onto which the membrane-electrode interface bonding layer is transferred; and forming a catalyst layer on the membrane-electrode interface bonding layer.

The membrane-electrode assembly having an interfacial adhesive layer according to the present invention can overcome the problem of interface detachment during operation of the fuel cell due to lack of compatibility between the hydrocarbon-based polymer electrolyte membrane and the catalyst layer containing the perfluorine-based ionomer. There is this.

Therefore, the present invention can minimize the increase in the interfacial resistance between the membrane-electrode, which occurs during the operation of the fuel cell, and the performance degradation due to this.

1 schematically shows a membrane-electrode assembly according to an embodiment of the present invention.
Figure 2 shows a membrane-electrode assembly manufacturing process according to an embodiment of the present invention.
3 is a SEM photograph of a membrane-electrode assembly according to an embodiment of the present invention. It is a cross-sectional view after transferring the catalyst layer on top.
4 is an interface desorption test result of a membrane-electrode assembly according to an embodiment of the present invention, (a) a membrane-electrode assembly to which a bonding layer made of only Nafion ionomer is applied, (b) a novel bonding layer consisting of two layers The applied hydrocarbon-based electrolyte membrane, (c) the membrane-electrode assembly transferred to the catalyst layer on the new bonding layer.
5 is a SEM photograph of a membrane-electrode assembly according to an embodiment of the present invention, wherein (a) and (b) are before putting it in boiling water, and (c) and (d) are a new bonding layer introduced after 48 hours. A view of the finished membrane and membrane-electrode assembly.
6 is a membrane-electrode assembly performance comparison unit cell performance test of Nafion 211 according to an embodiment of the present invention, SPAES50 to which a Nafion ionomer bonding layer is applied, and SPAES50 to which a novel bonding layer (CNBL) is applied (a) 65 ℃, 100% RH, (b) 65° C., 50% RH. (Active area: 25 cm ² , H ₂ /Air = 1.5: 2.0) This is the result.
7 is a comparison result of unit cell durability according to the bonding layer according to an embodiment of the present invention, (a) SPAES50 to which a Nafion ionomer bonding layer is applied, (b) SPAES50 to which a novel bonding layer (CNBL) is applied. Membrane-electrode conjugate. (Wet-dry cycle: anode/cell/cathode temperature=90 ℃/80 ℃/90 ℃, 2 min-2min cycle, anode/cathode gas flow = 2000 sccm/2000 sccm) Unit cell before and after wet-dry cycle evaluation performance result.

Hereinafter, the present invention will be described in detail. The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

In the present invention in order to solve the above problems, a perfluorinated ionomer layer; and a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer.

In the membrane-electrode interface bonding layer according to an embodiment of the present invention, the carbon-based material is graphite, graphite oxide, carbon black, graphitized carbon black, diamond-like carbon, fullerene, single-walled carbon nanotubes, multi-walled carbon nanotubes , carbon nanohorn, carbon nanowall, carbon nanofiber, carbon nanobrush, single layer graphene, multilayer graphene, and may be at least one selected from the group consisting of graphene oxide.

In addition, in the present invention, a hydrocarbon-based polymer electrolyte membrane; a membrane-electrode interface bonding layer comprising a perfluorine-based ionomer layer laminated on the hydrocarbon-based polymer electrolyte membrane and a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer; And it provides a membrane-electrode assembly comprising a catalyst layer laminated on the membrane-electrode interface bonding layer.

According to one embodiment of the present invention, a bonding layer composed of two layers may be applied between the hydrocarbon-based polymer electrolyte membrane and the electrode layer using the perfluorine-based ionomer. At this time, one layer is composed of a mixture of a carbon-based material such as carbon black, carbon nanotube, graphene, and the like and a perfluorine-based ionomer (carbon/Nafion blend layer), and the other layer on it consists only of a perfluorine-based ionomer.

In the membrane-electrode assembly according to an embodiment of the present invention, the mixture layer of the carbon-based material and the perfluorine-based ionomer is in contact with the hydrocarbon-based polymer electrolyte membrane, and the perfluorine-based ionomer layer is in contact with the electrode layer, so that the membrane-electrode bondability increase the

In the membrane-electrode assembly according to an embodiment of the present invention, the hydrocarbon-based polymer is a sulfonated poly(arylene ether sulfone) copolymer (SPAES), a sulfonated poly(ether) ketone) copolymer (sulfonated poly(ether ketone) copolymer; SPEK), sulfonated polyimide copolymer (SPI), sulfonated polysulfone copolymer (SPS), sulfonated poly Sulfonated polyphenylene copolymer (SPP), sulfonated poly(arylene sulfide sulfone) copolymer (SPASS), sulfonated poly(benzimidazole; SPBI) ), sulfonated poly(benzoxazole) (SPBO), and a combination thereof may be at least one selected from the group consisting of block copolymers.

In addition, the present invention provides a method comprising: forming a perfluorine-based ionomer layer on a substrate; forming a mixture layer of a carbon-based material and a perfluorine-based ionomer on the perfluorine-based ionomer layer to prepare a membrane-electrode interface bonding layer; transferring the membrane-electrode interface bonding layer to a carbon hydrogen-based polymer electrolyte membrane; acid-treating the carbon-hydrogen-based polymer electrolyte membrane onto which the membrane-electrode interface bonding layer is transferred; and forming a catalyst layer on the membrane-electrode interface bonding layer.

In the manufacturing method according to an embodiment of the present invention, the carbon-based material is graphite, graphite oxide, carbon black, graphitized carbon black, diamond-like carbon, fullerene, single-walled carbon nanotube, multi-walled carbon nanotube, carbon nanohorn , carbon nano walls, carbon nanofibers, carbon nano brushes, single-layer graphene, multi-layer graphene, and may be at least one selected from the group consisting of graphene oxide.

In the manufacturing method according to an embodiment of the present invention, the hydrocarbon-based polymer is a sulfonated poly(arylene ether sulfone) copolymer (SPAES), a sulfonated poly(ether ketone) ) copolymer (sulfonated poly(ether ketone) copolymer; SPEK), sulfonated polyimide copolymer (SPI), sulfonated polysulfone copolymer (SPS), sulfonated polyphenyl Sulfonated polyphenylene copolymer (SPP), sulfonated poly(arylene sulfide sulfone) copolymer (SPASS), sulfonated poly(sulfonated Polybenzimidazole; SPBI) , and may be at least one selected from the group consisting of block copolymers including sulfonated poly(benzoxazole) (SPBO) and combinations thereof.

For the hydrocarbon-based polymer electrolyte membrane used in manufacturing the membrane-electrode assembly according to an embodiment of the present invention, it is preferable to use a sulfonated poly(arylene ether sulfone) copolymer prepared according to the reaction of Scheme 1 below.

<Scheme 1>

In the manufacturing method according to an embodiment of the present invention, the step of forming the perfluorinated ionomer layer or the step of preparing the membrane-electrode interface bonding layer may be to use a spray method.

In the manufacturing method according to an embodiment of the present invention, the step of forming the catalyst layer may be any one of a decal process, a spray process, and a slot die coating process.

In addition, the present invention provides a fuel cell comprising the membrane-electrode assembly.

Hereinafter, embodiments and examples of the present invention will be described in detail so that a person with general knowledge in the technical field to which the present application pertains can easily carry out preferred embodiments of the present invention as shown in the accompanying drawings. In particular, the technical spirit of the present invention and its core configuration and operation are not limited by this. In addition, the content of the present invention may be implemented in various other types of equipment, and is not limited to the implementation examples and embodiments described herein.

1 schematically shows a membrane-electrode assembly according to an embodiment of the present invention.

A bonding layer composed of two layers as shown in FIG. 1 may be applied between the hydrocarbon-based polymer electrolyte membrane and the catalyst layers on both sides. One layer is composed of a mixture of a carbon-based material such as carbon black, carbon nanotube, graphene, and the like, and a perfluorine-based ionomer, and the other layer above it consists only of a perfluorine-based ionomer. The mixture layer of the carbon-based material and the perfluorine-based ionomer is in contact with the hydrocarbon-based polymer electrolyte membrane, and the perfluorine-based ionomer layer is in contact with the electrode layer and is located at the interface between the membrane and the electrode. The carbon-based material has a high specific surface area and good miscibility with hydrocarbon-based and perfluorinated polymers, thereby increasing the bonding force at the interface of the membrane-electrode assembly. In addition, the perfluorine-based ionomer layer blocks the electrochemical influence of the carbon-based material on the electrode layer and facilitates the electrode transfer process. The thickness of the two-layer bonding layer may be 1 μm to 10 μm.

Figure 2 shows a membrane-electrode assembly manufacturing process according to an embodiment of the present invention.

More specifically, the manufacturing method of the membrane-electrode assembly using the carbon/Nafion blend intermediate bonding layer, which is the manufacturing process, is as follows.

1) Apply 2 wt% Nafion ionomer solution onto the polyimide film as the base material using a spray device.

2) A 2 wt% solution in which carbon black, a carbon-based material, and Nafion ionomer, a perfluorine ionomer, are mixed in a ratio of 25:75 is coated on the same with a spray device.

3) Transfer the bonding layer consisting of two layers to the hydrocarbon-based polymer electrolyte membrane using a decal process, and then perform acid treatment. The hydrocarbon-based polymer electrolyte membrane was prepared by using a 50% sulfonated SPAES electrolyte membrane, and casting it on a PET release film using an NMP solvent.

4) A new membrane-electrode assembly is completed by transferring the catalyst layer coated on the polyimide film on the bonding layer through a decal process. (At this time, the transfer condition is that the temperature is up to 80~200℃, the pressure is 10~300kgf/cm2. And the time is set as ¹ ~30min.)

5) Then, assemble the unit cell and verify the electrochemical performance.

<Preparation Example> Preparation of membrane-electrode assembly

The SEM measurement of the membrane-electrode assembly was measured after sputter coating the specimen with platinum in vacuum for 2 minutes. In the case of a single-sided specimen, the film was prepared by breaking the film under liquid nitrogen.

3 is a SEM photograph of a membrane-electrode assembly according to an embodiment of the present invention. It is a cross-sectional view after transferring the catalyst layer on top.

As can be seen in FIG. 3, it was confirmed that the bonding layer composed of two layers and the catalyst layer were well transferred through the surface and cross-sectional photos using SEM. It was confirmed that the pion ionomer layer was in contact with the catalyst layer, and the thickness of the bonding layer was about 1 μm, suggesting that the increase in resistance of the electrolyte membrane could be minimized.

4 is an interface desorption test result of a membrane-electrode assembly according to an embodiment of the present invention, (a) a membrane-electrode assembly to which a bonding layer made of only Nafion ionomer is applied, (b) a novel bonding layer consisting of two layers The applied hydrocarbon-based electrolyte membrane, (c) the membrane-electrode assembly transferred to the catalyst layer on the new bonding layer.

The stability of the membrane-electrode assembly in boiling water was confirmed as an accelerated evaluation to confirm the interfacial bonding force between the membrane-electrode. It can be seen from the outer photograph of FIG. 4 that the catalyst layer was transferred well even in the case of the bonding layer using only the Nafion ionomer before boiling water evaluation. However, (a) the membrane-electrode assembly to which the bonding layer made of only Nafion ionomer was applied was confirmed that the catalyst layer was desorbed within 1 minute as soon as it was put in boiling water.

However, in the case of (b) and (c), on the contrary, in the case of the new two-layer bonding layer, both the bonding layer and the catalyst layer did not desorb from the electrolyte membrane even after 48 hours in boiling water.

5 is a SEM photograph of a membrane-electrode assembly according to an embodiment of the present invention, wherein (a) and (b) are before putting it in boiling water, and (c) and (d) are a new bonding layer introduced after 48 hours. A view of the membrane and the membrane-electrode assembly.

As can be seen from FIG. 5 , even in the SEM photograph, it was confirmed that the bonding layer and the catalyst layer did not detach at all even after 48 hours had elapsed when the bonding layer composed of two layers was introduced.

The results of Figures 4 and 5 above are due to the excellent miscibility between carbon black and hydrocarbon-based film, and the perfluorinated ionomer layer according to the present application; And the membrane-electrode interface bonding layer comprising a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer is effective and excellent in bonding between a hydrocarbon-based polymer electrolyte membrane and a catalyst layer containing a fluorine-based polymer. It was confirmed that it could be a new method.

6 is a membrane-electrode assembly performance comparison unit cell performance test of Nafion 211 according to an embodiment of the present invention, SPAES50 to which a Nafion ionomer bonding layer is applied, and SPAES50 to which a novel bonding layer (CNBL) is applied (a) 65 ℃, 100% RH, (b) 65° C., 50% RH. (Active area: 25 cm ² , H ₂ /Air = 1.5: 2.0) This is the result.

As can be seen in FIG. 6 , it was confirmed that the initial performance of the hydrocarbon-based membrane in which the bonding layer was introduced exhibited the same performance as the unit cell using the Nafion membrane in both high and low humidity, which resulted in a degradation in performance because the bonding layer did not act as a large resistance. indicates that it does not cause

7 is a comparison result of unit cell durability according to the bonding layer according to an embodiment of the present invention, (a) SPAES50 to which a Nafion ionomer bonding layer is applied, (b) SPAES50 to which a novel bonding layer (CNBL) is applied. Membrane-electrode conjugate. (Wet-dry cycle: anode/cell/cathode temperature=90 ℃/80 ℃/90 ℃, 2 min-2min cycle, anode/cathode gas flow = 2000 sccm/2000 sccm) Unit cell before and after wet-dry cycle evaluation performance result.

The above results are 900 cycles of accelerated durability evaluation of 2 minutes at 80 ° C. 150% RH and 2 minutes at 80 ° C. 0% RH as 1 cycle. In the case of , it was confirmed that the performance was maintained due to the improvement of the interfacial stability between the membrane-electrode, but in the case of the membrane-electrode assembly in which only Nafion ionomer was used as the bonding layer, the performance decreased rapidly.

This is due to interfacial desorption between the membrane-electrode, and through this technology, it was possible to improve the durability of the hydrocarbon-based membrane, and furthermore, it was confirmed that it is a technology that can easily bond hydrocarbon-based and fluorine-based polymers.

Claims (10)

perfluorinated ionomer layer; and
A membrane-electrode interface bonding layer comprising a mixture layer of a carbon-based material and a perfluorine-based ionomer laminated on the perfluorine-based ionomer layer. The method according to claim 1,
The carbon-based material includes graphite, graphite oxide, carbon black, graphitized carbon black, diamond-like carbon, fullerene, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanohorns, carbon nanowalls, carbon nanofibers, carbon nano brushes, A membrane-electrode interface bonding layer, characterized in that at least one selected from the group consisting of single-layer graphene, multi-layer graphene, and graphene oxide. hydrocarbon-based polymer electrolyte membrane;
The membrane-electrode interface bonding layer of any one of claims 1 to 3, which is laminated on the hydrocarbon-based polymer electrolyte membrane; and
Membrane-electrode assembly comprising a catalyst layer laminated on the membrane-electrode interface bonding layer. 4. The method according to claim 3,
The hydrocarbon-based polymer is a sulfonated poly(arylene ether sulfone) copolymer (SPAES), a sulfonated poly(ether ketone) copolymer; SPEK ), sulfonated polyimide copolymer (SPI), sulfonated polysulfone copolymer (SPS), sulfonated polyphenylene copolymer (SPP), sulfonated sulfonated poly(arylene sulfide sulfone) copolymer (SPASS), sulfonated poly(benzimidazole; SPBI), sulfonated poly(benzoxazole) ; SPBO) and a membrane-electrode assembly, characterized in that at least one selected from the group consisting of block copolymers comprising a combination thereof. forming a perfluorinated ionomer layer on a substrate;
forming a mixture layer of a carbon-based material and a perfluorine-based ionomer on the perfluorine-based ionomer layer to prepare a membrane-electrode interface bonding layer;
transferring the membrane-electrode interface bonding layer to a carbon hydrogen-based polymer electrolyte membrane;
acid-treating the carbon-hydrogen-based polymer electrolyte membrane onto which the membrane-electrode interface bonding layer is transferred; and
A method for manufacturing a membrane-electrode assembly comprising the step of forming a catalyst layer on the membrane-electrode interface bonding layer. 6. The method of claim 5,
The carbon-based material includes graphite, graphite oxide, carbon black, graphitized carbon black, diamond-like carbon, fullerene, single-walled carbon nanotube, multi-walled carbon nanotube, carbon nanohorn, carbon nanowall, carbon nanofiber, A method for manufacturing a membrane-electrode assembly, characterized in that at least one selected from the group consisting of carbon nano brushes, single-layer graphene, multi-layer graphene, and graphene oxide. 6. The method of claim 5,
The hydrocarbon-based polymer is a sulfonated poly(arylene ether sulfone) copolymer (SPAES), a sulfonated poly(ether ketone) copolymer; SPEK ), sulfonated polyimide copolymer (SPI), sulfonated polysulfone copolymer (SPS), sulfonated polyphenylene copolymer (SPP), sulfonated sulfonated poly(arylene sulfide sulfone) copolymer (SPASS), sulfonated poly(benzimidazole; SPBI), sulfonated poly(benzoxazole) ; SPBO) and a method for producing a membrane-electrode assembly, characterized in that at least one selected from the group consisting of block copolymers comprising a combination thereof. 6. The method of claim 5,
Forming the perfluorine-based ionomer layer or preparing the membrane-electrode interface bonding layer is a method of manufacturing a membrane-electrode assembly, characterized in that using a spray method. 6. The method of claim 5,
The step of forming the catalyst layer is a method of manufacturing a membrane-electrode assembly, characterized in that using any one of a decal process, a spray process, and a slot die coating process. A fuel cell comprising the membrane-electrode assembly according to claim 4.

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