Proton exchange membrane, preparation method and application

Abstract

The invention discloses a proton exchange membrane, a preparation method and application, and belongs to the technical field of proton exchange membrane fuel cells, the proton exchange membrane comprises perfluorosulfonic acid membranes, carboxylated carbon nanotubes located between the adjacent perfluorosulfonic acid membranes, and fluorinated aliphatic hydrocarbon containing silicon-oxygen bonds as a compatible layer, and chemical connection is formed between the perfluorosulfonic acid membrane and the carboxylated carbon nanotube. The preparation method comprises the following steps: carboxylating carbon nanotubes, increasing proton conduction sites, adding trimethoxysilane to obtain a supramolecular modified precursor, and constructing a supramolecular network structure with a perfluorosulfonic acid membrane. The proton exchange membrane is applied to preparation of a fuel cell. The proton exchange membrane prepared by the invention keeps high mechanical stability while having high radiation resistance, solves the problem of compatibility of a composite material caused by introduction of an inorganic material into a traditional proton exchange membrane, breaks through the bottleneck of comprehensive performance, and provides technical support for wide application of fuel cells in a nuclear energy technology.

Description

Technical Field

[0001] This application belongs to the field of proton exchange membrane fuel cell technology, and particularly relates to a proton exchange membrane, its preparation method and its application. Background Technology

[0002] Driven by both global energy structure transformation and environmental pollution control, fuel cells, as a highly efficient and clean energy conversion technology, have become a research hotspot in academia and industry in recent years. They directly convert the chemical energy of fuels (such as hydrogen and methanol) into electrical energy through electrochemical reactions, producing only water and heat with virtually no pollutant emissions. The proton exchange membrane (PEM) is the core component of a fuel cell, and its performance directly affects the fuel cell's efficiency, lifespan, and cost. Essentially, a PEM is a polymer material that selectively permeates protons, typically composed of polymers containing sulfonic acid groups. Its core functions are proton conduction, electron blocking, and gas isolation. Currently, the most widely used commercial PEM is the perfluorosulfonic acid membrane (Nafion), composed of a perfluorocarbon backbone and sulfonic acid side chains, exhibiting high chemical stability and proton conductivity. Therefore, PEM fuel cells have broad application prospects, such as in transportation, stationary power generation, portable power supplies, aerospace, nuclear energy, and military security.

[0003] High-energy radiation exists in both nuclear energy and aerospace environments. Traditional Nafion membranes have a brittle structure under irradiation and suffer from high methanol permeability, strong temperature and humidity dependence on proton conductivity, and high production costs, limiting their large-scale application in fuel cells. In recent years, non-fluorinated sulfonated aromatic polymers (such as sulfonated polyethersulfone, sulfonated polyetheretherketone, sulfonated polybenzimidazole, and sulfonated polyimide) have attracted widespread attention due to their good thermal stability and processing performance. However, these polymer membranes have low proton conductivity, and the increased sulfonation degree to improve proton conductivity leads to decreased membrane swelling and mechanical stability, thereby reducing their cycle stability and service life.

[0004] To address these issues, researchers have prepared organic-inorganic composite proton exchange membranes by doping inorganic materials into a polymer matrix, effectively improving the overall performance of the membrane material and fuel cell. However, this method also introduces the problem of composite material compatibility; that is, while the addition of inorganic materials increases radiation resistance, it reduces the mechanical properties of the composite membrane. Therefore, developing a composite membrane that possesses both high radiation resistance and good compatibility has significant application value. Summary of the Invention

[0005] This application aims to solve the technical problem of material compatibility caused by the introduction of inorganic materials into proton exchange membranes. To this end, this application provides a proton exchange membrane, a preparation method, and an application. The prepared proton exchange membrane has high radiation resistance while maintaining high mechanical stability, solving the composite material compatibility problem caused by the introduction of inorganic materials into traditional proton exchange membranes, breaking through the bottleneck of comprehensive performance, and providing technical support for the widespread application of fuel cells in nuclear energy technology.

[0006] In a first aspect, embodiments of this application provide a proton exchange membrane, comprising:

[0007] Perfluorosulfonic acid membranes serve as the structural basis for proton conduction;

[0008] Carboxylated carbon nanotubes are located between adjacent perfluorosulfonic acid membranes;

[0009] Fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds act as a compatibility layer, forming a chemical bond between the perfluorosulfonic acid film and the carboxylated carbon nanotubes.

[0010] In some embodiments, the proton exchange membrane is a supramolecular network structure constructed from a perfluorosulfonic acid membrane, carboxylated carbon nanotubes, and fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds. In this embodiment, the fluorinated aliphatic hydrocarbon segments containing silicon-oxygen bonds are chemically linked to the perfluorosulfonic acid groups of the perfluorosulfonic acid membrane, and the silicon-oxygen bonds of the fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds are chemically bonded to the carboxyl groups of the carboxylated carbon nanotubes.

[0011] Secondly, embodiments of this application provide a method for preparing a proton exchange membrane, comprising:

[0012] Multi-walled carbon nanotubes were carboxylated, and then trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane was mixed with the carboxylated multi-walled carbon nanotubes to prepare a supramolecular modified precursor. The supramolecular modified precursor was then combined with a perfluorosulfonic acid membrane to construct a supramolecular network structure.

[0013] In some embodiments, the preparation method specifically includes:

[0014] Multi-walled carbon nanotubes were dispersed in a first acidic solution, ultrasonicated, and then dried at 100-140℃. The dried solid was ground into powder, dispersed in a second acidic solution, ultrasonicated, washed with ultrapure water until neutral, and dried at 100-140℃ to obtain the first sample.

[0015] The powder of the first sample was dispersed in N,N-dimethylacetamide solution, and trimethoxysilane liquid was added dropwise. After thorough stirring, the sample was dried at 60-80℃ to obtain the supramolecular modified precursor.

[0016] The proton exchange membrane powder product and the supramolecular modified precursor were co-dispersed in an N,N-dimethylacetamide solution and stirred at room temperature to obtain a casting solution.

[0017] The casting solution is dropped onto a glass plate, which is then placed in an environment of 60-80℃ to dry. The temperature is then raised to 120-150℃ for a period of time, and after naturally cooling to room temperature, the glass plate is removed to obtain a proton exchange membrane with a supramolecular network structure.

[0018] In some embodiments, the ratio of multi-walled carbon nanotubes to the first acidic solution is 2.0-3.0 g : 0.18-0.50 mol.

[0019] In some embodiments, the ratio of the first sample, N,N-dimethylacetamide, and trimethoxysilane is 2.0-3.0 g : 0.10-0.32 mol : 0.5-1.0 g.

[0020] In some embodiments, the ratio of perfluorosulfonic acid membrane, supramolecular modified precursor and N,N-dimethylacetamide is 1.9-2.0 g : 0.02-0.1 g : 0.05-0.22 mol.

[0021] In some embodiments, the preparation method specifically includes:

[0022] Weigh 2.0-3.0 g of multi-walled carbon nanotubes and disperse them in 30-50 mL of hydrochloric acid solution with a concentration of 6-10 mol / L. After sonication for 4-6 hours, dry them in an oven at 100-140℃ for 12-24 hours. Place the resulting solid in an agate mortar and grind it into powder. Prepare a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid in a certain ratio. Disperse the ground MWCNTs powder in 40-60 mL of the mixed acid solution. After sonication for 6-12 hours, wash with ultrapure water until neutral and dry in an oven at 100-140℃ for 12-24 hours to obtain the MWCNTs-COOH sample, i.e., the first sample.

[0023] Weigh 2.0-3.0 g of MWCNTs-COOH powder and disperse it in 20-30 mL of N,N-dimethylacetamide solution with a concentration of 5.0-10.8 mol / L. Slowly add 1.0-3.6 mol / L of C9H... 13 0.5-1.0 g of liquid F9O3Si was stirred at room temperature for 12-24 hours and then dried in an oven at 60-80℃ for 6-12 hours to obtain a supramolecular modified precursor.

[0024] Weigh 1.9-2.0 g of perfluorosulfonic acid membrane powder and 0.02-0.1 g of supramolecular modified precursor and co-disperse them in 10-20 mL of N,N-dimethylacetamide solution with a concentration of 5.0-10.8 mol / L to obtain a solution with a supramolecular modified precursor mass fraction of 1-5 wt%. After stirring at room temperature for 24-48 hours, a casting solution is obtained.

[0025] The casting solution was dropped onto a 10cm×10cm glass plate and placed in a vacuum drying oven at 60-80℃ for 12-24 hours. The temperature was then raised to 120-150℃ and maintained for 4-6 hours. After naturally cooling to room temperature, the plate was removed to obtain a supramolecular network proton exchange membrane.

[0026] Thirdly, this application provides an application of a proton exchange membrane, wherein the product obtained by the above-described proton exchange membrane preparation method is used to manufacture a proton exchange membrane fuel cell.

[0027] In some embodiments, the supramolecular network structure proton exchange membrane is activated and pretreated before manufacturing the proton exchange membrane fuel cell:

[0028] Place the supramolecular network proton exchange membrane in a 1%-10% H2O2 solution at 50-90℃ for 1-2 hours. Then remove the supramolecular network proton exchange membrane, wash it with ultrapure water until neutral, and then soak it in a 1-2 mol / L H2SO4 solution for 1-2 hours while maintaining the temperature at 60-80℃. Remove it and wash it with ultrapure water until neutral for later use.

[0029] As can be seen from the above technical solution, the beneficial effects of this application are as follows:

[0030] 1. The proton exchange membrane of this application, through the good reactivity and bonding ability of fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds, can form strong chemical bonds with carboxylated carbon nanotubes, and at the same time, it can generate strong intermolecular forces with perfluorosulfonic acid membranes. Thus, the fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds act as a compatibility layer to achieve good interfacial compatibility and bonding between the perfluorosulfonic acid membrane and the carboxylated carbon nanotubes. The proton exchange membrane prepared in this way achieves a high and stable proton conductivity of the perfluorosulfonic acid membrane, while ensuring the structural stability of the proton exchange membrane through the above-mentioned chemical bonding. Since the multi-carbon nanotubes can effectively disperse radiation energy and reduce the radiation damage to the membrane, the proton exchange membrane maintains high mechanical stability while having high radiation resistance. This solves the compatibility problem of composite materials caused by the introduction of inorganic materials into traditional proton exchange membranes, breaks through the bottleneck of comprehensive performance, and provides technical support for the widespread application of fuel cells in nuclear energy technology.

[0031] 2. The preparation method of this application is easy to operate, the product is inexpensive, and it is suitable for large-scale production. Specifically, carboxyl groups are introduced into the surface of multi-walled carbon nanotubes through a carboxylation process. These carboxylated multi-walled carbon nanotubes can then undergo a condensation reaction with the silane groups in trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane to form a strong covalent bond, creating a supramolecular modified precursor. The fluorine-containing long chains grafted onto this supramolecular modified precursor interact with the fluorocarbon skeleton of the perfluorosulfonic acid membrane to prepare a supramolecular network structure. This achieves interfacial bonding between the multi-walled carbon nanotubes and the perfluorosulfonic acid membrane, providing excellent proton transport channels and increasing the number of proton conduction sites. The resulting proton exchange membrane exhibits excellent radiation resistance, mechanical stability, and proton conductivity.

[0032] 3. Application of this application: By applying the above-mentioned proton exchange membrane in fuel cells, it is possible to ensure high proton conductivity while having stronger mechanical stability, improving crack resistance, and increasing the lifespan and durability of the proton exchange membrane, thereby comprehensively enhancing the performance of the fuel cell. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced one by one below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other embodiments and drawings can be obtained based on these drawings without creative effort. Various schematic diagrams according to the embodiments of this application are shown in the accompanying drawings. These drawings are not necessarily drawn to scale. For the purpose of clarity, some details have been enlarged and some details may have been omitted.

[0034] Figure 1 This is a schematic diagram of the proton exchange membrane structure of this application;

[0035] Figure 2 This is a schematic diagram illustrating the preparation principle of the proton exchange membrane in this application;

[0036] Figure 3 This is a schematic diagram of a fuel cell with a proton exchange membrane according to this application;

[0037] Figure 4 This is a comparison of the proton conductivity of supramolecular network structure proton exchange membranes and organic-inorganic composite membranes with different mass fractions in Example 1 and each comparative example;

[0038] Figure 5 This is a comparison diagram of the mechanical stability of proton exchange membranes with supramolecular network structures and organic-inorganic composite membranes with different mass fractions in Example 1 and each comparative example.

[0039] Figure 6 This is a comparison of the proton conductivity of the three high-performance supramolecular network proton exchange membranes and the Nafion recast membrane under γ-irradiation with a cumulative absorbed dose of 600 kGy.

[0040] Figure 7 This is a comparison of the mechanical stability of the three high-performance supramolecular network proton exchange membranes and the Nafion recast membrane under γ-irradiation with a cumulative absorbed dose of 600 kGy.

[0041] Illustration: 1. Perfluorosulfonic acid membrane; 2. Carboxylated carbon nanotubes; 3. Fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds. Detailed Implementation

[0042] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application. The described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, they can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] This application is described below with reference to the accompanying drawings and specific embodiments:

[0044] Please refer to Figure 1 According to a first aspect of this application, a proton exchange membrane is provided, comprising a perfluorosulfonic acid membrane 1, carboxylated carbon nanotubes 2, and a fluorinated aliphatic hydrocarbon containing silicon-oxygen bonds 3. In the structure constructed from the perfluorosulfonic acid membrane 1, carboxylated carbon nanotubes 2, and fluorinated aliphatic hydrocarbon containing silicon-oxygen bonds 3, each structural unit includes a structure of two layers of perfluorosulfonic acid membrane 1, with the perfluorosulfonic acid membrane 1 serving as the structural basis for proton conduction; the carboxylated carbon nanotubes 2 are located between adjacent layers of perfluorosulfonic acid membrane 1; and the fluorinated aliphatic hydrocarbon containing silicon-oxygen bonds 3 serves as a compatibility layer, forming a chemical connection between the interface of the perfluorosulfonic acid membrane 1 and the carboxylated carbon nanotubes 2.

[0045] In some embodiments, the proton exchange membrane is a supramolecular network structure constructed from a perfluorosulfonic acid membrane 1, carboxylated carbon nanotubes 2, and fluorinated aliphatic hydrocarbons 3 containing silicon-oxygen bonds. The fluorinated aliphatic hydrocarbon segments of the fluorinated aliphatic hydrocarbons 3 are chemically linked to the perfluorosulfonic acid groups of the perfluorosulfonic acid membrane 1, and the silicon-oxygen bonds of the fluorinated aliphatic hydrocarbons 3 are chemically bonded to the carboxyl groups of the carboxylated carbon nanotubes 2. This supramolecular network structure not only maintains high structural stability but also provides a stable and efficient proton conduction channel, ensuring high proton conductivity.

[0046] Please refer to Figure 2 According to a second aspect of this application, a method for preparing a proton exchange membrane is provided, comprising:

[0047] Multi-walled carbon nanotubes (MWCNTs) were carboxylated, and then a supramolecular modified precursor was prepared by mixing trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane with the carboxylated MWCNTs. This supramolecular modified precursor was then combined with a perfluorosulfonic acid membrane 1 to construct a supramolecular network structure. Carboxylation of carbon nanotubes increases the number of sites required for proton conduction, thereby improving proton conductivity. Adding MWCNTs to the perfluorosulfonic acid membrane 1 helps disperse irradiation energy, thus enhancing the membrane's radiation resistance. Introducing trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane as a bridge connecting the carboxylated carbon nanotube 2 structure and the perfluorosulfonic acid membrane 1 structure, a supramolecular network proton exchange membrane was constructed, enhancing the compatibility of the two structures and thus improving the mechanical stability of the composite membrane, resulting in high mechanical strength.

[0048] In some embodiments, the preparation method specifically includes:

[0049] S1. Disperse multi-walled carbon nanotubes in a first acidic solution, sonicate them, and then dry them at 100-140℃. Grind the dried solid into powder, disperse it in a second acidic solution, sonicate it, wash it with ultrapure water until neutral, and dry it at 100-140℃ to obtain the first sample.

[0050] S2. Disperse the powder of the first sample in N,N-dimethylacetamide (DMAc) solution, add trimethoxysilane liquid dropwise, stir thoroughly, and then dry in an environment of 60-80℃ to obtain a supramolecular modified precursor. The prepared supramolecular modified precursor is to enhance the compatibility of MWCNTs-COOH with the proton exchange membrane, thereby improving the mechanical stability of the composite membrane.

[0051] S3. The proton exchange membrane powder product and the supramolecular modified precursor are co-dispersed in an N,N-dimethylacetamide (DMAc) solution and stirred at room temperature to obtain a casting solution. The amount of supramolecular modified precursor added significantly affects the proton conductivity and mechanical strength of the composite membrane.

[0052] S4. Drop the casting solution onto a glass plate, then place the glass plate in an environment of 60-80℃ to dry, and then continue to heat to 120-150℃ for a period of time. After naturally cooling to room temperature, remove the plate to obtain a supramolecular network structure proton exchange membrane, denoted as SN-CNTs / Nafion.

[0053] In some embodiments, in step S1 above, multi-walled carbon nanotubes refer to commercially available unpurified multi-walled carbon nanotubes (MWCNTs).

[0054] In some embodiments, in step S1 above, the ratio of multi-walled carbon nanotubes to the first acidic solution is 2.0-3.0 g: 0.18-0.50 mol.

[0055] In some embodiments, in step S1 above, the first acidic solution is hydrochloric acid, and the second acidic solution is a mixed acid solution prepared by concentrated nitric acid and concentrated sulfuric acid in a certain proportion.

[0056] In some embodiments, in step S2 above, trimethoxysilane refers to: 1.0-3.6 mol / L of trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane (C9H... 13 F9O3Si).

[0057] In some embodiments, in step S3 above, the proton exchange membrane powder product refers to a commercially available proton exchange membrane, such as Nafion-H resin powder.

[0058] In some embodiments, in step S2 above, the ratio of the first sample, N,N-dimethylacetamide and trimethoxysilane is 2.0-3.0 g: 0.10-0.32 mol: 0.5-1.0 g.

[0059] In some embodiments, in step S3 above, the ratio of perfluorosulfonic acid membrane 1, supramolecular modified precursor and N,N-dimethylacetamide is 1.9-2.0g: 0.02-0.1g: 0.05-0.22mol.

[0060] In some embodiments, in step S3 above, 1-5 wt% of a supramolecular modified precursor and a proton exchange membrane powder product (Nafion-H resin powder) are selected to construct a proton exchange membrane with a supramolecular network structure.

[0061] In some embodiments, the preparation method specifically includes:

[0062] S1. Weigh 2.0-3.0 g of multi-walled carbon nanotubes and disperse them in 30 mL of hydrochloric acid solution with a concentration of 6-10 mol / L. After sonicating for 4-6 hours, dry in an oven at 100-140℃ for 12-24 hours. Place the resulting solid in an agate mortar and grind it into powder. Prepare a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid in a set ratio. Disperse the ground MWCNTs powder in 40-60 mL of the mixed acid solution. After sonicating for 6-12 hours, wash with ultrapure water until neutral and dry in an oven at 100-140℃ for 12-24 hours to obtain the MWCNTs-COOH sample, i.e., the first sample.

[0063] S2. Weigh 2.0-3.0 g of MWCNTs-COOH powder and disperse it in 20-30 mL of N,N-dimethylacetamide solution with a concentration of 5.0-10.8 mol / L. Slowly add 1.0-3.6 mol / L of C9H... 13 0.5-1.0 g of F9O3Si liquid was stirred at room temperature for 12-24 hours and then dried in an oven at 60-80℃ for 6-12 hours to obtain a supramolecular modified precursor.

[0064] S3. Weigh 1.9-2.0g of perfluorosulfonic acid membrane 1 powder (Nafion-H resin powder) and 0.02-0.1g of supramolecular modified precursor and co-disperse them in 10-20mL of N,N-dimethylacetamide solution with a concentration of 5.0-10.8mol / L to obtain a solution with a supramolecular modified precursor mass fraction of 1-5wt%. After stirring at room temperature for 24-48 hours, a casting solution is obtained. Select 1-5wt% of the supramolecular modified precursor and Nafion to construct a supramolecular network structure proton exchange membrane. This ensures that the composite membrane has high mechanical strength and a large number of proton conduction sites, thus the composite membrane has high proton conductivity.

[0065] S4. Drop the casting solution onto a 10cm×10cm glass plate and place it in a vacuum drying oven at 60-80℃ for 12-24 hours. Raise the temperature to 120-150℃ and maintain it for 4-6 hours. After naturally cooling to room temperature, remove the plate to obtain a supramolecular network proton exchange membrane (SN-CNTs / Nafion membrane).

[0066] Please refer to Figure 3 The third aspect of this application provides an application of a proton exchange membrane, wherein the product obtained by the above-described proton exchange membrane preparation method is used to manufacture a proton exchange membrane fuel cell; that is, a proton exchange membrane with a supramolecular network structure is prepared by the above-described steps S1-S4, and the specific preparation process is described in the above-described steps. Alternatively, the above-described proton exchange membrane, namely the supramolecular network structure constructed from a perfluorosulfonic acid membrane 1, carboxylated carbon nanotubes 2, and fluorinated aliphatic hydrocarbons containing silicon-oxygen bonds 3, can also be used, and the construction method is described in the above-described proton exchange membrane.

[0067] In some embodiments, the supramolecular network structure proton exchange membrane is activated and pretreated before manufacturing the proton exchange membrane fuel cell:

[0068] The supramolecular network proton exchange membrane was placed in a 1%-10% H₂O₂ solution at 50-90℃ for 1-2 hours. Afterward, the membrane was removed, washed with ultrapure water until neutral, and then soaked in a 1-2 mol / L H₂SO₄ solution for 1-2 hours, maintaining the temperature at 60-80℃. It was then removed and washed with ultrapure water until neutral before use. This activation pretreatment of the supramolecular network proton exchange membrane primarily removes impurities to ensure its chemical activity.

[0069] Experiments were conducted using the preparation method described in this application, and the examples are as follows:

[0070] Example 1

[0071] S1. Weigh 2.0g of unpurified MWCNTs and disperse them in 30mL of 6mol / L HCl solution. After sonication for 6 hours, wash with water until neutral and dry in an oven at 120℃ for 24 hours. Place the resulting solid in an agate mortar and grind it into powder. Prepare a mixed acid solution with HNO3 and H2SO4 in a 1 / 3 volume ratio, where HNO3 is common concentrated nitric acid (65%) and H2SO4 is common concentrated sulfuric acid (98.3%). Disperse the ground MWCNTs powder in 50mL of the mixed acid solution, sonicate for 12 hours, wash with ultrapure water until neutral, and dry in an oven at 120℃ for 24 hours to obtain the MWCNTs-COOH sample.

[0072] S2. Weigh 2.0 g of the MWCNTs-COOH powder obtained in S1 and disperse it in 20 mL of 10.8 mol / L DMAc solution. Slowly add 3.6 mol / L C9H... 13 1.0 g of F9O3Si liquid was stirred at room temperature for 24 hours and then dried in an oven at 70℃ for 12 hours to obtain a supramolecular modified precursor.

[0073] S3. Weigh 1.97g of Nafion-H resin powder and 0.03g of the supramolecular modified precursor obtained in S2 and co-disperse them in 10mL of DMAc solution with a concentration of 10.8mol / L. Stir at room temperature for 48 hours to obtain casting solution.

[0074] S4. Drop the obtained casting solution onto a glass plate with a size of 10cm×10cm, place it in a vacuum drying oven at 70℃ and dry for 12 hours. Raise the temperature to 140℃ and maintain it for 4 hours. After naturally cooling to room temperature, take it out to obtain a 1.5wt% -SN-CNTs / Nafion membrane.

[0075] S5. All membranes must be activated and pretreated before testing. The specific steps are as follows: Place the supramolecular network proton exchange membrane in a 5% H2O2 solution at 60℃ for 1 hour. Then, take out the membrane and wash it with ultrapure water until neutral. Then, soak it in a 1mol / L H2SO4 solution for 1 hour while maintaining the temperature at 60℃. Take it out and wash it with ultrapure water until neutral for later use.

[0076] S6. Cut the membrane into dumbbell-shaped samples with a length of 3.5cm and a narrow side width of 2mm, and use a universal testing machine with a 5kg sensor to test the membrane tensile properties.

[0077] S7. Cut the membrane into 2cm*2cm square samples, immerse them in water for 24 hours, and test the AC impedance of the membrane using a proton conductivity test fixture and an electrochemical workstation. The test conditions are 0.1Hz-10 Hz. 5 Hz is used to obtain the proton conductivity.

[0078] In Comparative Example 1, except for steps S1 and S2, no supramolecular modification precursor was added in step S3. 2.0 g of Nafion powder was directly dispersed in 10 mL of DMAc solution to cast a film, and the remaining steps were the same as in Example 1.

[0079] In Comparative Example 2, except that the amount of Nafion-H resin powder in S3 was increased to 1.99 g and the amount of supramolecular modified precursor obtained in S2 was reduced to 0.01 g, all other steps were the same as in Example 1, and a 0.5 wt% -SN-CNTs / Nafion membrane was obtained.

[0080] In Comparative Example 3, except that the amount of Nafion-H resin powder in S3 was increased to 1.98 g and the amount of supramolecular modified precursor obtained in S2 was reduced to 0.02 g, all other steps were the same as in Example 1, and a 1 wt% -SN-CNTs / Nafion membrane was obtained.

[0081] In Comparative Example 4, except that the Nafion-H resin powder in S3 was reduced to 1.96 g and the supramolecular modified precursor obtained in S2 was increased to 0.04 g, the remaining steps were the same as in Example 1, and a 2wt% -SN-CNTs / Nafion membrane was obtained.

[0082] In Comparative Example 5, except that the amount of Nafion-H resin powder in S3 was increased to 1.94 g and the amount of supramolecular modified precursor obtained in S2 was increased to 0.06 g, all other steps were the same as in Example 1, and a 3wt% -SN-CNTs / Nafion membrane was obtained.

[0083] Comparative Example 6 was identical to Example 1 except that the Nafion-H resin powder in S3 was reduced to 1.90 g and the supramolecular modified precursor obtained in S2 was increased to 0.1 g, and 5 wt% -SN-CNTs / Nafion membrane was obtained.

[0084] Comparative Example 7, except for step S2, requires replacing the supramolecular modified precursor in S3 with the MWCNTs-COOH sample. The remaining steps are the same as in Comparative Example 3, to obtain an organic-inorganic proton exchange membrane (denoted as 1wt%-CNTs / Nafion).

[0085] Comparative Example 8, except for step S2, requires replacing the supramolecular modified precursor in step S3 with the MWCNTs-COOH sample. The remaining steps are the same as in Example 1, resulting in a 1.5 wt% CNTs / Nafion membrane.

[0086] Comparative Example 9, except for step S2, requires replacing the supramolecular modified precursor in step S3 with the MWCNTs-COOH sample. The remaining steps are the same as those in Comparative Example 4, resulting in a 2wt% CNTs / Nafion membrane.

[0087] Figure 4 This is a comparison of the proton conductivity of supramolecular network structure proton exchange membranes and organic-inorganic composite membranes with different mass fractions in the examples and comparative examples. Figure 5 This is a comparison of the mechanical stability of supramolecular network proton exchange membranes and organic-inorganic composite membranes with different mass fractions in the examples and comparative examples. Figure 4 A comparison of the proton conductivity of proton exchange membranes with different mass fractions of supramolecular network structures shows that the 1.5 wt% -SN-CNTs / Nafion membrane has a proton conductivity of 53.67 mS / cm, which is superior to the 26.57 mS / cm of the 1.5 wt% -CNTs / Nafion membrane and the 31.76 mS / cm of the Nafion recast membrane. The proton conductivity of the supramolecular network structure proton exchange membrane is twice that of the traditional organic-inorganic composite membrane. Although both have the same number of proton conduction sites, the proton transport channels of the supramolecular network structure membrane are more stable and efficient, thus resulting in a significant increase in proton conductivity. Meanwhile... Figure 5 The mechanical strength of the 1.5wt% -SN-CNTs / Nafion membrane (29.16 MPa) was also higher than that of the 1.5wt% -CNTs / Nafion membrane (17.72 MPa) and the Nafion recast membrane (26.49 MPa). This is because the poor compatibility of traditional organic-inorganic composite structures leads to lower mechanical strength, while C9H... 13 The addition of F9O3Si enhances the compatibility between the two, and the constructed supramolecular network structure exhibits excellent stability, thus significantly improving the mechanical strength of the proton exchange membrane. Meanwhile, the material ratio of the supramolecular modified precursor is a crucial factor influencing the overall performance of the SN-CNTs / Nafion membrane; the 1.5wt% SN-CNTs / Nafion membrane achieves high proton conductivity while enhancing its structural stability.

[0088] Example 2

[0089] The 1.5 wt% -SN-CNTs / Nafion membrane prepared in Example 1 was placed in 60 In a Co irradiation source environment, γ irradiation at 0.71 Gy / s was carried out, with a cumulative absorbed dose of 600 kGy. After irradiation, the membrane was cut for proton conduction and mechanical property testing.

[0090] Comparative Example 10: The Nafion recast membrane prepared in Comparative Example 1 was placed in... 60 In a Co irradiation source environment, γ irradiation at 0.71 Gy / s was carried out, with a cumulative absorbed dose of 600 kGy. After irradiation, the membrane was cut for proton conduction and mechanical property testing.

[0091] Comparative Example 11: The 1 wt% -SN-CNTs / Nafion membrane prepared in Comparative Example 3 was placed in... 60 In a Co irradiation source environment, γ irradiation at 0.71 Gy / s was carried out, with a cumulative absorbed dose of 600 kGy. After irradiation, the membrane was cut for proton conduction and mechanical property testing.

[0092] Comparative Example 12: The 2 wt% -SN-CNTs / Nafion membrane prepared in Comparative Example 4 was placed in... 60 In a Co irradiation source environment, γ irradiation at 0.71 Gy / s was carried out, with a cumulative absorbed dose of 600 kGy. After irradiation, the membrane was cut for proton conduction and mechanical property testing.

[0093] In Comparative Example 13, the mass of unpurified MCNTs weighed in step S1 of Example 1 was increased to 3.0 g, and the remaining steps were the same as in Example 1.

[0094] Comparative Example 14 uses a 6 mol / L HCl solution with a volume of 50 mL in step S1 of Example 1, and a 40 mL mixed acid solution. All other steps are the same as in Example 1.

[0095] Comparative Example 15 uses a 10 mol / L HCl solution with a volume of 50 mL in step S1 of Example 1, and a 60 mL mixed acid solution. All other steps are the same as in Example 1.

[0096] Comparative Example 16 uses an HCl solution with a concentration of 10 mol / L and a volume of 30 mL in step S1 of Example 1, and the remaining steps are the same as in Example 1.

[0097] Comparative Example 17 uses an HCl solution with a concentration of 6 mol / L and a volume of 50 mL in step S1 of Example 3, and the remaining steps are the same as in Example 1.

[0098] Comparative Example 18 uses an HCl solution with a concentration of 10 mol / L and a volume of 50 mL in step S1 of Example 3, and the remaining steps are the same as in Example 1.

[0099] Comparative Example 19 uses an HCl solution with a concentration of 10 mol / L and a volume of 30 mL in step S1 of Example 3, and the remaining steps are the same as in Example 1.

[0100] Comparative Example 20 increased the mass of MWCNTs-COOH powder in step S2 of Example 1 to 3.0 g, while the remaining steps were the same as in Example 1;

[0101] In Comparative Example 21, the DMAc solution used in step S2 of Example 1 was 10.8 mol / L with a volume of 30 mL, and the remaining steps were the same as in Example 1.

[0102] In Comparative Example 22, the DMAc solution used in step S2 of Example 1 was 5.0 mol / L with a volume of 20 mL, and the remaining steps were the same as in Example 1.

[0103] In Comparative Example 23, the DMAc solution used in step S2 of Example 1 was 5.0 mol / L with a volume of 30 mL, and the remaining steps were the same as in Example 1.

[0104] Comparative Example 24 uses step S2 (C9H) from Example 1. 13 The F9O3Si liquid used had a concentration of 3.6 mol / L and a mass of 0.5 g. All other steps were the same as in Example 1.

[0105] Comparative Example 25 uses step S2 (C9H) from Example 1. 13 The F9O3Si liquid used had a concentration of 1.0 mol / L and a mass of 0.5 g. All other steps were the same as in Example 1.

[0106] Comparative Example 26 uses step S2 (C9H) from Example 1. 13 The F9O3Si liquid used had a concentration of 1.0 mol / L and a mass of 1.0 g. All other steps were the same as in Example 1.

[0107] In Comparative Example 27, the DMAc solution used in step S3 of Example 1 was 10.8 mol / L with a volume of 20 mL, and the remaining steps were the same as in Example 1.

[0108] In Comparative Example 28, the DMAc solution used in step S3 of Example 1 was 5.0 mol / L with a volume of 10 mL, and the remaining steps were the same as in Example 1.

[0109] Comparative Example 29 uses a DMAc solution with a concentration of 5.0 mol / L and a volume of 20 mL in step S3 of Example 1, and the remaining steps are the same as in Example 1.

[0110] In the process of preparing proton exchange membranes in the above embodiments, there are only slight differences in the amount of intermediate products. The properties and quality of the final proton exchange membrane products meet the requirements and can achieve the same or similar technical effects.

[0111] Figure 6 and Figure 7 The figures show a comparison of proton conductivity and mechanical stability between the three supramolecular network proton exchange membranes with superior performance in the examples and the Nafion recast membrane after a cumulative absorbed dose of 600 kGy under γ-irradiation. Figure 5 and Figure 6 The comparison shows that the modified proton exchange membrane exhibits a significantly reduced decrease in proton conductivity and tensile strength after irradiation. The 1.5wt% -SN-CNTs / Nafion membrane demonstrates particularly remarkable radiation resistance, maintaining a high proton conductivity of 45.12 mS / cm and a tensile strength of 21.28 MPa after irradiation, far exceeding the proton conductivity of 16.46 mS / cm and the tensile strength of 13.09 MPa of the traditional Nafion recast membrane. The perfluorosulfonic acid structure of the traditional Nafion recast membrane is irradiation-brittle; the addition of carbon nanotubes effectively disperses the irradiation energy, thereby reducing the degree of irradiation damage to the membrane. Simultaneously, the C9H... 13 The addition of F9O3Si enhances the compatibility between the two, and the constructed supramolecular network structure film has high mechanical stability and high proton conductivity, further demonstrating excellent radiation resistance.

[0112] Regarding the specific implementation methods of this application, it should be noted that:

[0113] In the description of this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," "connected," etc., should be interpreted broadly. For example, "fixed" can refer to a fixed connection, a detachable connection, or an integral molding; "connection" can refer to a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal connection of two components or the interaction between two components, unless otherwise expressly limited; "connected" can refer to the internal connection of two parts and the connection between two parts, or the spatial connection between them, whereby the two parts are directly or indirectly connected through the part forming the space. The terms "set," "installed," "equipped with," "configured," etc., should also be interpreted broadly. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0114] In the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the system or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. All directional indications are only used to explain the relative positional relationship and movement between components in a specific orientation. If the specific orientation changes, the directional indication will also change accordingly.

[0115] In the description of this application, the use of terms such as "some embodiments," "optional embodiments," "example," "specific example," "optional example," or "optional embodiment," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application, but does not imply that these embodiments illustrate and describe all possible forms of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0116] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments; the above description should not be construed as a limitation of the present invention. Technical solutions between various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application. Although embodiments of the present application have been shown and described, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. Those skilled in the art will understand that various other specific changes and combinations of embodiments based on the technical teachings disclosed in this application, without departing from the essence of the present application, are still within the scope of protection defined by the claims of the present invention and their equivalent technical solutions.

Claims

1. A proton exchange membrane, characterized by, The application relates to a proton exchange membrane, comprising: a perfluorosulfonic acid membrane (1) as a structure basis for proton conduction; carboxylated carbon nanotubes (2) between adjacent perfluorosulfonic acid membranes (1); and a siloxane bond-containing fluorinated aliphatic hydrocarbon (3) as a compatible layer, which forms a chemical connection between the perfluorosulfonic acid membrane (1) and the carboxylated carbon nanotubes (2). The proton exchange membrane is constructed by the perfluorosulfonic acid membrane (1), the carboxylated carbon nanotubes (2) and the siloxane bond-containing fluorinated aliphatic hydrocarbon (3), wherein the fluorinated aliphatic hydrocarbon segment of the siloxane bond-containing fluorinated aliphatic hydrocarbon (3) forms a chemical connection with the perfluorosulfonic acid group of the perfluorosulfonic acid membrane (1), and the siloxane bond of the siloxane bond-containing fluorinated aliphatic hydrocarbon (3) forms a chemical bond with the carboxyl group of the carboxylated carbon nanotubes (2). The application further relates to a preparation method of the proton exchange membrane, comprising the following steps: carboxylating multi-walled carbon nanotubes, then mixing trimethoxysilane (1H, 1H, 2H, 2H-nonafluorohexyl) silane with the carboxylated multi-walled carbon nanotubes to prepare a supramolecular modified precursor, and constructing a supramolecular network structure by the supramolecular modified precursor and a perfluorosulfonic acid membrane (1). Specifically, the method comprises the following steps: dispersing multi-walled carbon nanotubes in a first acidic solution, drying the multi-walled carbon nanotubes in an environment with a temperature of 100-140 DEG C after ultrasonic treatment, grinding the dried solid into powder, dispersing the powder in a second acidic solution, washing the powder with ultrapure water until the powder is neutral, and drying the powder in an environment with a temperature of 100-140 DEG C to obtain a first sample; dispersing the powder of the first sample in an N, N-dimethylacetamide solution, adding trimethoxysilane liquid dropwise, stirring sufficiently, and drying the mixture in an environment with a temperature of 60-80 DEG C to obtain a supramolecular modified precursor; co-dispersing a proton exchange membrane powder product and the supramolecular modified precursor in an N, N-dimethylacetamide solution, stirring at room temperature to obtain a casting solution; dropping the casting solution on a glass plate, drying the glass plate in an environment with a temperature of 60-80 DEG C, then continuously heating the glass plate to a temperature of 120-150 DEG C for a period of time, naturally reducing the temperature of the glass plate to room temperature, and taking out the glass plate to obtain a supramolecular network structure proton exchange membrane.

2. The proton exchange membrane according to claim 1, characterized in that, The proportion of the multi-walled carbon nanotubes and the first acidic solution is 2.0-3.0 g: 0.18-0.50 mol.

3. A method for producing a proton exchange membrane, characterized by, The proportion of the first sample, the N, N-dimethylacetamide and the trimethoxysilane is 2.0-3.0 g: 0.10-0.32 mol: 0.5-1.0 g. The proportion of the perfluorosulfonic acid membrane (1), the supramolecular modified precursor and the N, N-dimethylacetamide is 1.9-2.0 g: 0.02-0.1 g: 0.05-0.22 mol.

4. The method for producing a proton exchange membrane according to claim 3, characterized by, Specifically, ​ ​ ​ ​ 5. The method for preparing a proton exchange membrane according to claim 4, characterized by, ​ 6. The method of claim 4, wherein the proton exchange membrane is prepared by the steps of: ​ 7. The method of claim 4, wherein the proton exchange membrane is prepared by the steps of: ​ 8. The method of claim 4-7, wherein the proton exchange membrane is prepared by the steps of: ​ Take 2.0-3.0 g of multi-walled carbon nanotubes (MWCNTs) and disperse them in 30-50 mL of a hydrochloric acid solution with a concentration of 6-10 mol / L. Ultrasonic treatment is performed for 4-6 hours, and then the resulting solid is dried in an oven at 100-140°C for 12-24 hours. The obtained powder is placed in an agate mortar and ground into a powder. Concentrated nitric acid and concentrated sulfuric acid are mixed in a certain proportion to obtain a mixed acid solution. The ground MWCNTs powder is then dispersed in 40-60 mL of the mixed acid solution, and ultrasonic treatment is performed for 6-12 hours. After that, the solution is washed with ultrapure water until it is neutral. The resulting solution is dried in an oven at 100-140°C for 12-24 hours to obtain a MWCNTs-COOH sample, which is the first sample. The MWCNTs-COOH powder 2.0-3.0 g is weighed and dispersed in 20-30 mL of N,N-dimethylacetamide solution with a concentration of 5.0-10.8 mol / L, 1.0-3.6 mol / L of C9H 13 0.5-1.0 g of liquid F9O3Si, stirring at room temperature for 12-24 hours, drying in an oven at 60-80 °C for 6-12 hours to obtain a supramolecular modified precursor; Take 1.9-2.0 g of a perfluorosulfonic acid membrane (1) and 0.02-0.1 g of the supramolecular modification precursor, and disperse them in 10-20 mL of a N,N-dimethylacetamide solution with a concentration of 5.0-10.8 mol / L to obtain a solution with a supramolecular modification precursor mass fraction of 1-5 wt%. After stirring at room temperature for 24-48 hours, a casting solution is obtained. The casting solution is dropped onto a glass plate with a size of 10 cm x 10 cm, and then placed in a vacuum drying oven at 60-80°C for 12-24 hours. The temperature is then increased to 120-150°C and maintained for 4-6 hours. After naturally cooling to room temperature, the supramolecular network structure proton exchange membrane is obtained.

9. Use of a proton exchange membrane, characterized in that The product obtained by the method for preparing a proton exchange membrane according to any one of claims 1-8 is used to manufacture a proton exchange membrane fuel cell.

10. Use of a proton exchange membrane according to claim 9, characterized in that, Before manufacturing the proton exchange membrane fuel cell, the supramolecular network structure proton exchange membrane is activated and pretreated as follows: The supramolecular network structure proton exchange membrane is placed in a 1%-10% H2O2 solution at 50-90°C for 1-2 hours. After that, the supramolecular network structure proton exchange membrane is taken out, washed with ultrapure water until it is neutral, and then soaked in a 1-2 mol / L H2SO4 solution for 1-2 hours while maintaining the temperature at 60-80°C. The supramolecular network structure proton exchange membrane is taken out and washed with ultrapure water until it is neutral for use.

Images