Preparation method of composite proton exchange membrane and composite proton exchange membrane

Abstract

The invention discloses a preparation method of a composite proton exchange membrane and the composite proton exchange membrane. The preparation method comprises the following steps: determining a long-chain branched polyperfluorosulfonic acid membrane; the long branched chain type polyperfluorinated sulfonic acid membrane is obtained by pouring a long branched chain type polyperfluorinated sulfonic acid resin solution on the surface of a substrate, strickling the long branched chain type polyperfluorinated sulfonic acid resin solution and then drying the long branched chain type polyperfluorinated sulfonic acid resin solution. Or one of a Gore-Select membrane, a Nafion211 membrane, a Nafion212 membrane, an HP membrane, an XL100 membrane and an NC700 membrane is selected as a long branched chain type polyperfluorosulfonic acid membrane; then respectively blade-coating the surfaces of the two sides of the long-branched-chain polyperfluorinated sulfonic acid resin solution with a short-branched-chain polyperfluorinated sulfonic acid resin solution to obtain a proton exchange membrane; carrying out hot pressing on the proton exchange membrane at the temperature of 80-150 DEG C; and after the pressure maintaining time of 30-180 seconds, the composite proton exchange membrane is obtained. Therefore, the short-branched-chain type polyperfluorinated sulfonic acid resin layers are coated on the two sides of the long-branched-chain type polyperfluorinated sulfonic acid membrane, so that the redesign of the structure of the proton exchange membrane is realized. The water-retaining agent has excellent high-temperature water-retaining performance and low swelling rate at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and in particular to a method for preparing a composite proton exchange membrane and the composite proton exchange membrane. Background Art

[0002] Proton exchange membrane is one of the most core components in devices such as hydrogen fuel cells and water electrolyzers. Commercial proton exchange membranes are usually polyperfluorosulfonic acid resin membranes. Currently, the most widely used is the Nafion long-branched polyperfluorosulfonic acid membrane. Although it has excellent properties, it still has the defects of poor mechanical properties and low ion conductivity under high temperature and low humidity environments. Therefore, short-branched polyperfluorosulfonic acid membranes were subsequently developed on the market. It has a higher degree of crystallinity. Compared with the Nafion long-branched type, although its thermal transition temperature is higher, the water absorption rate and ion exchange capacity (IEC) are also higher, but the swelling deformation is larger. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a composite proton exchange membrane preparation method and a composite proton exchange membrane, which can simultaneously have excellent high-temperature water retention performance and low swelling rate to avoid high swelling deformation.

[0004] According to a first aspect of the present invention, a method for preparing a composite proton exchange membrane is provided, comprising:

[0005] Determine a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is obtained by pouring a long-chain branched polyperfluorosulfonic acid resin solution on the surface of a substrate, scraping the long-chain branched polyperfluorosulfonic acid resin solution flat and then drying it; or select one from Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane;

[0006] respectively scraping a short-chain branched polyperfluorosulfonic acid resin solution on both sides of the long-chain branched polyperfluorosulfonic acid membrane to obtain a proton exchange membrane;

[0007] Hot pressing the proton exchange membrane at a temperature of 80-150 degrees;

[0008] After a pressure holding time of 30 to 180 seconds, a composite proton exchange membrane is obtained.

[0009] Optionally, the mass concentration of the long-chain branched polyperfluorosulfonic acid resin solution is 5%-35%;

[0010] Optionally, the mass concentration of the short-chain branched polyperfluorosulfonic acid resin solution is 5%-25%.

[0011] Optionally, the ion equivalent of the short-chain branched polyperfluorosulfonic acid resin solution is 400-900 g / mol.

[0012] Optionally, the difference between the ion equivalent of the long-chain branched polyperfluorosulfonic acid resin solution and the ion equivalent of the short-chain branched polyperfluorosulfonic acid resin solution is greater than or equal to 100 g / mol.

[0013] Optionally, the ion equivalent of the long-chain branched polyperfluorosulfonic acid resin solution is 900-1500 g / mol.

[0014] Optionally, the composite proton exchange membrane has a thickness of 10-250 μm.

[0015] Optionally, the hot pressing pressure is 1-6MPa.

[0016] According to the second aspect of the present invention, a composite proton exchange membrane is provided, comprising a long-chain branched polyperfluorosulfonic acid membrane located in a middle layer and short-chain branched polyperfluorosulfonic acid membrane layers located on both sides of the middle layer; the composite proton exchange membrane is prepared using the aforementioned composite proton exchange membrane preparation method.

[0017] The above one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0018] The embodiments of the present specification provide a method for preparing a composite proton exchange membrane and a composite proton exchange membrane, by determining a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is obtained by pouring a long-chain branched polyperfluorosulfonic acid resin solution on the surface of a substrate, scraping the long-chain branched polyperfluorosulfonic acid resin solution flat and then drying it; or selecting one from Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane; then scraping a short-chain branched polyperfluorosulfonic acid resin solution on both sides of the long-chain branched polyperfluorosulfonic acid membrane to obtain a proton exchange membrane; hot pressing the proton exchange membrane at a temperature of 80-150 degrees; after a holding time of 30-180 seconds, a composite proton exchange membrane is obtained. In this way, by coating the short-chain branched polyperfluorosulfonic acid resin layer on both sides of the long-chain branched polyperfluorosulfonic acid membrane, the structure of the proton exchange membrane is redesigned. When the working environment temperature gradually increases, the water loss of the short-chain branched polyperfluorosulfonic acid resin on both sides is not obvious, and the long-chain branched polyperfluorosulfonic acid resin is in the middle position. The resins on both sides protect the water content in the middle and can still transmit protons faster. On the other hand, by adjusting the ratio of the long-chain branched polyperfluorosulfonic acid resin and the short-chain branched polyperfluorosulfonic acid resin, the overall water absorption deformation rate of the proton membrane can be adjusted. This is because the addition of the middle long-chain branched polyperfluorosulfonic acid resin layer inhibits the swelling of the two outer short-chain branched polyperfluorosulfonic acid resin layers.

[0019] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

[0021] Figure 1 A flow chart of a method for preparing a composite proton exchange membrane in an embodiment of the present invention is shown.

[0022] Figure 2 A schematic diagram of a composite proton exchange membrane in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Proton exchange membrane is one of the most core components in devices such as hydrogen fuel cells and water electrolyzers. Commercial proton exchange membranes are usually polyperfluorosulfonic acid resin membranes. Currently, the most widely used is the Nafion long-branched polyperfluorosulfonic acid membrane. Although it has excellent properties, it still has the defects of poor mechanical properties and low ion conductivity under high temperature and low humidity environments. Therefore, short-branched polyperfluorosulfonic acid membranes were subsequently developed on the market. It has a higher degree of crystallinity. Compared with the Nafion long-branched type, although its thermal transition temperature is higher, the water absorption rate and ion exchange capacity (IEC) are also higher, but the swelling deformation is larger.

[0028] Based on the above situation, the embodiment of the present invention provides a composite proton exchange membrane preparation method, combined with Figure 1 The method includes steps 101 to 104:

[0029] Step 101: determining a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is obtained by pouring a long-chain branched polyperfluorosulfonic acid resin solution on the surface of a substrate, scraping the long-chain branched polyperfluorosulfonic acid resin solution flat, and then drying; or selecting one from the existing Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane;

[0030] In this embodiment, the composite proton exchange membrane is a sandwich structure, specifically a three-layer sandwich structure of a long-chain branched polyperfluorosulfonic acid membrane middle layer and short-chain branched polyperfluorosulfonic acid membrane layers on both sides.

[0031] The long-chain branched polyperfluorosulfonic acid membrane can be selected from the existing commercial Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane.

[0032] Long-chain branched polyperfluorosulfonic acid membranes can also be made of long-chain branched polyperfluorosulfonic acid resins. Specifically, they include:

[0033] A long-chain branched polyperfluorosulfonic acid resin solution is poured onto the surface of the substrate, and the long-chain branched polyperfluorosulfonic acid resin solution is scraped flat and then dried.

[0034] The substrate material is a glass plate. The ion equivalent of the long-chain branched polyperfluorosulfonic acid resin solution is 900-1500 g / mol. The mass concentration of the long-chain branched polyperfluorosulfonic acid resin solution is 5%-35%. The drying temperature is 80-150 degrees. For example, drying at a temperature of 80 degrees for 30-100 minutes.

[0035] Step 102: coating the surfaces of both sides of the long-chain branched polyperfluorosulfonic acid membrane with a short-chain branched polyperfluorosulfonic acid resin solution to obtain a proton exchange membrane;

[0036] In this embodiment, the short-chain branched polyperfluorosulfonic acid resin solution is scraped on both sides of the long-chain branched polyperfluorosulfonic acid film with a scraper, and then dried. The drying temperature range is 80-150 degrees. If 80 degrees is selected for drying, the drying time is 30-100 minutes.

[0037] The mass concentration of the short-chain branched polyperfluorosulfonic acid resin solution is 5%-25%, and the ion equivalent of the short-chain branched polyperfluorosulfonic acid resin solution is 400-900 g / mol.

[0038] It should be noted that the difference between the ion equivalent of the long-chain branched polyperfluorosulfonic acid resin solution and the ion equivalent of the short-chain branched polyperfluorosulfonic acid resin solution in this embodiment is preferably greater than or equal to 100 g / mol.

[0039] Step 103: hot-pressing the proton exchange membrane at a temperature of 80-150 degrees; wherein the hot-pressing pressure ranges from 1-6 MPa.

[0040] Step 104: After a pressure holding time of 30-180 seconds, a composite proton exchange membrane is obtained.

[0041] In this embodiment, after the proton exchange membrane is hot-pressed, it needs to be kept under pressure for a period of time, and the holding time can be in the range of 30-180 seconds.

[0042] The thickness of the composite proton exchange membrane after pressure maintenance is about 10-250 μm.

[0043] In order to facilitate understanding and implementation by those skilled in the art, the following embodiments are provided:

[0044] Example 1

[0045] A long-chain branched commercial polyperfluorosulfonic acid membrane with an ion exchange equivalent (EW value) of 1050 g / mol is selected; the membrane is placed on a glass plate, and a short-chain branched polyperfluorosulfonic acid resin solution with an EW value of 850 g / mol is scraped on the surface of the membrane, with a mass concentration of 10wt%, and then placed in a drying oven and dried at 80 degrees for 30 minutes; the short-chain branched polyperfluorosulfonic acid resin solution is also scraped on the other side of the long-chain branched commercial polyperfluorosulfonic acid membrane, and then placed in a drying oven and dried at 80 degrees for 40 minutes; then hot pressing is performed on the membrane, with a hot pressing temperature of 120°C, a pressure of 1.5 MPa, and a holding time of 40 seconds to finally obtain a composite proton exchange membrane.

[0046] Example 2

[0047] A long-chain branched polyperfluorosulfonic acid resin solution with a mass concentration of 20wt% and an EW value of 1000g / mol is poured onto a glass plate and scraped, and then placed in a drying oven for drying at 85 degrees for 40 minutes to obtain a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is placed on a glass plate, and a short-chain branched polyperfluorosulfonic acid resin solution with an EW of 850g / mol and a mass concentration of 10wt% is scraped on the surface of the long-chain branched polyperfluorosulfonic acid membrane, and then placed in a drying oven for drying at 80 degrees for 30 minutes; the short-chain branched polyperfluorosulfonic acid resin solution is also scraped on the other side of the long-chain branched commercial polyperfluorosulfonic acid membrane, and then placed in a drying oven for drying at 80 degrees for 40 minutes; then hot pressing is performed, the hot pressing temperature is 120 degrees, the hot pressing pressure is 1.5MPa, and the holding time is 40s, and finally a composite proton exchange membrane is obtained.

[0048] Comparative Example

[0049] The difference between this comparative example and Example 1 is that the short-chain branched polyperfluorosulfonic acid resin solution is changed into a long-chain branched commercial polyperfluorosulfonic acid resin solution, the EW value is 1050 g / mol, and the other parameters and conditions are exactly the same as those in Example 1.

[0050] Performance test: According to the national standard GB / T 20042.3-2022, the composite proton exchange membranes prepared in Example 1, Example 2 and the comparative example were tested, and the data are shown in the table below.

[0051]

[0052]

[0053] As can be seen from the table, the tensile strength of Example 1 is the largest. This is because the commercial proton membrane selected is ePTFE-enhanced, so the prepared composite proton exchange membrane has a small thickness and good mechanical properties. In terms of water absorption performance, both Example 1 and Example 2 are greater than the comparative example because the addition of short-chain polyperfluorosulfonic acid resin makes it have excellent water retention performance at 100°C. At the same time, in terms of area swelling rate, the short-chain polyperfluorosulfonic acid resin has little effect on the overall swelling rate, all within 5%. In the comparison of proton conductivity at 90°C / 30%RH, the composite membrane with the addition of short-chain polyperfluorosulfonic acid resin is significantly higher than the comparative example, that is, the composite membrane without the addition of short-chain polyperfluorosulfonic acid resin.

[0054] In summary, the embodiment of the present specification provides a method for preparing a composite proton exchange membrane, by determining a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is obtained by pouring a long-chain branched polyperfluorosulfonic acid resin solution on the surface of a substrate, scraping the long-chain branched polyperfluorosulfonic acid resin solution flat and then drying it; or selecting one from Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane; then scraping the short-chain branched polyperfluorosulfonic acid resin solution on both sides of the long-chain branched polyperfluorosulfonic acid membrane to obtain a proton exchange membrane; hot pressing the proton exchange membrane at a temperature of 80-150 degrees; after a holding time of 30-180 seconds, a composite proton exchange membrane is obtained. In this way, by coating the short-chain branched polyperfluorosulfonic acid resin layer on both sides of the long-chain branched polyperfluorosulfonic acid membrane, the structure of the proton exchange membrane is redesigned. When the working environment temperature gradually increases, the water loss of the short-chain branched polyperfluorosulfonic acid resin on both sides is not obvious, and the long-chain branched perfluorosulfonic acid resin is in the middle position. The resins on both sides protect the water content in the middle, and protons can still be transmitted faster. On the other hand, by regulating the ratio of the long-chain branched polyperfluorosulfonic acid resin and the short-chain branched polyperfluorosulfonic acid resin, the overall water absorption deformation rate of the proton membrane can be regulated. This is because the addition of the middle long-chain branched polyperfluorosulfonic acid resin layer inhibits the swelling of the two outer layers of short-chain branched polyperfluorosulfonic acid resin. The composite proton exchange membrane prepared in this embodiment can be used in a high temperature and low humidity environment, and has its own water retention function.

[0055] Based on the same inventive concept, Figure 2 As shown, an embodiment of the present invention further provides a composite proton exchange membrane, comprising a long-chain branched polyperfluorosulfonic acid membrane located in the middle layer and a short-chain branched polyperfluorosulfonic acid membrane layer located on both sides of the middle layer; the composite proton exchange membrane is prepared using the aforementioned composite proton exchange membrane preparation method, and the method steps are described above and will not be repeated here.

[0056] In summary, a composite proton exchange membrane provided in an embodiment of the present specification is obtained by determining a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is obtained by pouring a long-chain branched polyperfluorosulfonic acid resin solution on the surface of a substrate, scraping the long-chain branched polyperfluorosulfonic acid resin solution flat and then drying it; or selecting one from Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane; then scraping a short-chain branched polyperfluorosulfonic acid resin solution on both sides of the long-chain branched polyperfluorosulfonic acid membrane to obtain a proton exchange membrane; hot pressing the proton exchange membrane at a temperature of 80-150 degrees; after a holding time of 30-180 seconds, a composite proton exchange membrane is obtained. In this way, by coating the short-chain branched polyperfluorosulfonic acid resin layer on both sides of the long-chain branched polyperfluorosulfonic acid membrane, the structure of the proton exchange membrane is redesigned. When the working environment temperature gradually increases, the water loss of the short-chain branched polyperfluorosulfonic acid resin on both sides is not obvious, and the long-chain branched polyperfluorosulfonic acid resin is in the middle position. The resins on both sides protect the water content in the middle and can still transmit protons faster. On the other hand, by adjusting the ratio of the long-chain branched polyperfluorosulfonic acid resin and the short-chain branched polyperfluorosulfonic acid resin, the overall water absorption deformation rate of the proton membrane can be adjusted. This is because the addition of the middle long-chain branched polyperfluorosulfonic acid resin layer inhibits the swelling of the two outer short-chain branched polyperfluorosulfonic acid resin layers.

[0057] The above are only various embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a composite proton exchange membrane, characterized in that: include: Determine a long-chain branched polyperfluorosulfonic acid membrane; the long-chain branched polyperfluorosulfonic acid membrane is obtained by pouring a long-chain branched polyperfluorosulfonic acid resin solution on the surface of a substrate, scraping the long-chain branched polyperfluorosulfonic acid resin solution flat and then drying it; or select one from Gore-Select membrane, Nafion211 membrane, Nafion212 membrane, HP membrane, XL100 membrane, and NC700 membrane as the long-chain branched polyperfluorosulfonic acid membrane; respectively scraping a short-chain branched polyperfluorosulfonic acid resin solution on both sides of the long-chain branched polyperfluorosulfonic acid membrane to obtain a proton exchange membrane; Hot pressing the proton exchange membrane at a temperature of 80-150 degrees; After a pressure holding time of 30 to 180 seconds, a composite proton exchange membrane is obtained.

2. The method according to claim 1, characterized in that The mass concentration of the long-chain branched polyperfluorosulfonic acid resin solution is 5%-35%.

3. The method according to claim 1, characterized in that The mass concentration of the short-chain branched polyperfluorosulfonic acid resin solution is 5%-25%.

4. The method according to claim 1, characterized in that: The ion equivalent of the short-chain branched polyperfluorosulfonic acid resin solution is 400-900 g / mol.

5. The method according to any one of claims 1 to 4, characterized in that: The difference between the ion equivalent of the long-chain branched polyperfluorosulfonic acid resin solution and the ion equivalent of the short-chain branched polyperfluorosulfonic acid resin solution is greater than or equal to 100 g / mol.

6. The method according to claim 1, characterized in that The ion equivalent of the long-chain branched polyperfluorosulfonic acid resin solution is 900-1500 g / mol.

7. The method according to claim 1, characterized in that The thickness of the composite proton exchange membrane is 10-250 μm.

8. The method according to claim 1, characterized in that The hot pressing pressure is 1-6MPa.

9. A composite proton exchange membrane, characterized in that: It comprises a long-chain branched polyperfluorosulfonic acid membrane located in the middle layer and a short-chain branched polyperfluorosulfonic acid membrane layer located on both sides of the middle layer; the composite proton exchange membrane is prepared using the composite proton exchange membrane preparation method described in any one of claims 1-8.

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