A method for preparing a high-performance dispersion liquid of perfluorosulfonic acid resin for a hydrogen fuel cell membrane electrode

Abstract

The application discloses a preparation method of high-performance perfluorosulfonic acid resin dispersion liquid for hydrogen fuel cell membrane electrode, characterized in that: perfluorosulfonic acid resin is put into a reaction kettle, water and a polar organic solvent are added, a synergistic additive fluorocarbon alcohol is added, under the protection of inert gas, the temperature is raised to 40-60 DEG C, and stirring reaction is carried out for 12-24 hours; then a supported radical quencher is added, under the protection of inert gas, heating is carried out to 90-140 DEG C, and stirring reaction is carried out for 12-24 hours, to obtain dispersion liquid B; the dispersion liquid B is transferred into a high-pressure homogenizer for homogenization treatment, and then the high-performance perfluorosulfonic acid resin dispersion liquid containing the supported radical quencher and being stable and uniformly dispersed for hydrogen fuel cell membrane electrode is prepared. The high-performance perfluorosulfonic acid resin dispersion liquid for hydrogen fuel cell membrane electrode prepared by the method can be mainly used for preparing a catalytic layer in a proton exchange membrane fuel cell membrane electrode assembly, and can improve the proton conduction efficiency and chemical stability of the catalytic layer.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen fuel cell materials technology, and relates to a method for preparing a high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode assembly (MEA). The high-performance perfluorosulfonic acid resin dispersion prepared by this invention is mainly used in the preparation of the catalyst layer in the MEA assembly of proton exchange membrane fuel cells (PEMFCs), which can improve the proton conduction efficiency and chemical stability of the catalyst layer. Background Technology

[0002] Hydrogen fuel cells convert the chemical energy of hydrogen and oxygen into electrical energy through an electrochemical reaction, offering advantages such as zero emissions and high efficiency, making them one of the core technologies in the future clean energy field. The membrane electrode assembly (MEA), as the "heart" of the hydrogen fuel cell, directly determines the battery's output power and cycle life. Perfluorosulfonic acid resin dispersion is a key binder-conductor material for the MEA catalyst layer; it not only needs to bind catalyst particles to form a stable structure but also needs to construct continuous proton conduction channels to ensure the efficient conduction of the redox reaction (ORR).

[0003] Currently, the preparation of perfluorosulfonic acid resin dispersions faces two major problems that restrict the improvement of membrane electrode performance. The first is low proton conduction efficiency. In traditional dispersions, resin molecular chains are severely aggregated, and sulfonic acid groups are unevenly distributed, leading to the breakage of proton conduction channels, increased proton transport resistance within the catalyst layer, and slower ORR reaction kinetics. Existing technologies include CN103146001A ("A method for preparing a perfluorosulfonic acid resin solution with uniformly dispersed molecular chains"), CN104140542A ("A method for preparing a perfluorosulfonic acid resin solution"), and CN112608494A... Methods for preparing perfluorosulfonic acid resin dispersions have been disclosed, some of which use water-polar organic solvents and high temperature and pressure to improve resin solubility and obtain uniformly dispersed perfluorosulfonic acid resin dispersions. However, when using binary systems such as water-polar organic solvents, there are two drawbacks: First, the strong hydrophobicity of the main chain leads to the formation of hydrophobic aggregates between molecular chains, making it difficult for solvent molecules to penetrate into the aggregates, resulting in uneven dispersion of molecular chains. Second, hydrogen bonds are easily formed between the -SO3H groups of the hydrophilic side chains, further aggravating intermolecular aggregation, thus preventing the sulfonic acid groups from fully exerting their proton conductivity. Secondly, it has poor chemical stability (or durability). Perfluorosulfonic acid resin is easily attacked by free radicals, leading to molecular chain breakage and insufficient long-term operational stability of the membrane electrode. Existing technologies disclose CN 120565699 "A high-durability catalyst slurry and its preparation method and application", which improves the chemical durability of the membrane electrode by adding free radical quenchers to the catalyst slurry. However, the surface of the free radical quenchers lacks hydrophilic groups and has poor compatibility with perfluorosulfonic acid resin. They are prone to agglomeration during dispersion, resulting in low free radical capture efficiency. Moreover, they are prone to loss in the humid and hot environment in which the membrane electrode operates, making it impossible to use stably for a long time. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology of perfluorosulfonic acid resin dispersions when used in membrane electrodes, such as low proton conductivity and poor chemical durability. This invention provides a composite perfluorosulfonic acid resin dispersion for membrane electrodes, specifically a method for preparing a high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrodes. By incorporating a fluorocarbon alcohol synergist, the weak van der Waals forces between the perfluorosulfonic acid resin backbone break the hydrophobic aggregation between the backbones. Furthermore, the hydroxyl groups in the fluorocarbon alcohol can form a continuous hydrogen bond network with water and polar organic solvents, significantly improving the compatibility of the resin and solvent system, increasing dispersion uniformity, and thus enhancing the proton conductivity of the solution. The addition of a (sulfonated silica nanoparticle) supported free radical quencher increases the compatibility of the free radical quencher with the perfluorosulfonic acid resin, reduces agglomeration during dispersion, and the free radical quencher is embedded on the surface of the silica nanoparticles, reducing migration and loss of the free radical quencher during operation, significantly improving stability.

[0005] The present invention relates to a method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, characterized by comprising the following steps: a. Add perfluorosulfonic acid resin (solid) to a reaction vessel, add water and polar organic solvent (as mixed solvent), add fluorocarbon alcohol as a synergist, and under the protection of inert gas, heat to 40-60℃ and stir for 12-24 h to allow the solvent to fully swell the perfluorosulfonic acid resin to obtain dispersion A. The fluorocarbon alcohol is one or a mixture of two or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, perfluorooctylethanol, and perfluorohexylethanol; b. Add a supported free radical quencher to the dispersion A obtained in step a. Under the protection of an inert gas, heat to 90-140°C and stir for 12-24 hours to further disperse the perfluorosulfonic acid resin and fully mix it with the supported free radical quencher to obtain dispersion B. c. After transferring the dispersion B obtained in step b into a high-pressure homogenizer (with a certain pressure set) for (multiple) homogenization treatments, a stable and uniformly dispersed high-performance perfluorosulfonic acid resin dispersion containing a loaded free radical quencher for hydrogen fuel cell membrane electrodes is obtained.

[0006] In this invention, the supported free radical quencher mentioned in step b is one or a mixture of two or more of the following: sulfonated silica nanoparticles supported cerium oxide, sulfonated silica nanoparticles supported cerium sulfate, sulfonated silica nanoparticles supported cerium nitrate, sulfonated silica nanoparticles supported manganese oxide, sulfonated silica nanoparticles supported chromium oxide, sulfonated silica nanoparticles supported aluminum oxide, and sulfonated silica nanoparticles supported cobalt oxide.

[0007] The preparation method of the supported free radical quencher is as follows: Using a hydrothermal-in-situ synthesis method, 80-120 parts by weight of deionized water, 20-50 parts by weight of ethanol, and 0.5-2 parts by weight of hexadecyltrimethylammonium bromide (CTAB) are added to a high-pressure reactor lined with polytetrafluoroethylene. After stirring and dissolving, 5-15 parts by weight of TEOS (tetraethyl orthosilicate) are added, and stirring is continued for 30 minutes. Then, a free radical quencher (which can be one or a mixture of two or more of cerium oxide, cerium sulfate, cerium nitrate, manganese oxide, chromium oxide, aluminum oxide, and cobalt oxide) and 2-8 parts by weight of p-styrene sulfonic acid are added, and stirring is continued for 10 minutes. Mix thoroughly for 30 minutes; add ammonia dropwise to adjust pH to 8-9, seal the reactor, and react at 120-150℃ for 24-48 hours; after the reaction, allow to cool naturally, centrifuge, and wash the solid obtained after centrifugation with deionized water and ethanol multiple times to remove surfactants and impurities; dry the washed solid at 60-80℃ (e.g., 70℃) overnight, and then calcine at 450-500℃ (e.g., 500℃) for 2-4 hours (e.g., 3 hours) to remove surfactants and crystallize the free radical quencher, obtaining the target product, the supported free radical quencher.

[0008] In this invention, the weight percentage ratio (composition) of the raw materials (components) perfluorosulfonic acid resin, water, polar organic solvent, and fluorocarbon alcohol in step a is as follows: perfluorosulfonic acid resin (solid content) is 5%–30%, water is 47%–63%, polar organic solvent is 18%–22%, and fluorocarbon alcohol is 5%–10%, and the total of all raw materials (components) is 100%. The amount of the supported free radical quencher used in step b is 0.5% to 9.5% of the amount of perfluorosulfonic acid resin (solid weight).

[0009] In this invention: the perfluorosulfonic acid resin described in step a has a polytetrafluoroethylene structure (-CF2-CF2-) as its main chain, and -[OCF2C(CF3)F] as its main chain. m -O[CF2CF2] n -SO3H is composed of side chains, where m=0 or 1, n=1 or 2.

[0010] In the present invention: the perfluorosulfonic acid resin product manufactured in step a is any one or a mixture of two or more of the following: Aquivion® PW-72S, Aquivion® PW-79S, Aquivion® PW-87S, and Aquivion® PW-98S from Solvay (Chemical) Shanghai Co., Ltd.

[0011] In this invention, the EW value (EW value, i.e., ion exchange equivalent) of the perfluorosulfonic acid resin in step a is 700-1000 g / mol.

[0012] In this invention, the polar organic solvent mentioned in step a is one or a mixture of two or more of the following: n-propanol, n-butanol, ethanol, isopropanol, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0013] In this invention, the inert gas mentioned in steps a and b is one or a mixture of two or more of nitrogen, helium, and argon.

[0014] In the present invention: the heating rate in step a is preferably 0.5℃ / min to 2℃ / min, and the stirring speed is preferably 100 to 200 r / min; The stirring speed in step b is preferably 300-600 r / min.

[0015] In this invention: the pressure for homogenization in the homogenizer described in step c is 300 to 1200 bar, and the number of homogenization cycles can be 1 to 10.

[0016] Compared with the prior art, the present invention has the following features and beneficial effects: (1) The present invention provides excellent proton conduction performance: The addition of the carbon alcohol additive utilizes the amphiphilic properties of its molecular structure, which combines hydrophobic fluorocarbon segments and hydrophilic hydroxyl segments, to interact with the fluorocarbon backbone and sulfonic acid side chains of the perfluorosulfonic acid resin. On the one hand, the fluorocarbon segments and the hydrophobic backbone of the resin exhibit similar miscibility, weakening the strong van der Waals forces and hydrophobic aggregation between the resin molecular chains, thus transforming the molecular chains from a tightly aggregated state to a loosely dispersed state. On the other hand, hydrogen bonds are formed between the hydroxyl groups and the sulfonic acid groups, improving the interfacial compatibility between the resin and the alcohol-water mixed solvent, allowing the resin to fully swell and disperse uniformly in the system, thereby constructing a tight, continuous, and interconnected ion cluster transport channel, reducing proton conduction resistance, and significantly improving the proton conduction rate and the electrochemical performance of the membrane electrode.

[0017] (2) The membrane electrode exhibits excellent chemical durability using this invention: The sulfonated silica nanoparticle-supported free radical quencher introduced has sulfonic acid groups on its surface, which have similar chemical structures and polarities to the sulfonic acid side chains of perfluorosulfonic acid resin. The two can form good hydrogen bond bonds and interfacial compatibility, effectively reducing the aggregation and sedimentation of free radical quencher particles in the resin dispersion, and achieving uniform dispersion at the nanoscale. At the same time, the free radical quencher is confined in situ and loaded on the surface of the silica carrier, rather than being simply physically blended. Under the hydrothermal and electrochemical environment of long-term operation of fuel cells, it can significantly inhibit the dissolution, migration and loss of small molecule free radical quenchers, enabling them to continuously and efficiently remove active groups such as hydroxyl radicals and hydrogen peroxide, slowing down the oxidative degradation of the main chain and side chains of perfluorosulfonic acid resin, thereby greatly improving the chemical stability of the membrane electrode and increasing its chemical durability to more than 500 hours.

[0018] (3) The preparation process of the present invention is simple, easy to operate, and highly practical. Attached Figure Description

[0019] Figure 1 Comparative data on the electrochemical performance of membrane electrodes prepared from the perfluorosulfonic acid resin dispersions obtained in Example 1 and Comparative Example 1; The figure illustrates that, compared to Comparative Example 1, Example 1 exhibits a higher output voltage at the same current density, demonstrating that the addition of fluorocarbon alcohols can significantly enhance the proton conductivity of the catalyst layer.

[0020] Figure 2 The chemical durability test data are for the membrane electrode prepared from the perfluorosulfonic acid resin dispersion obtained in Example 2. Figure 3 Chemical durability test data of membrane electrodes prepared from the perfluorosulfonic acid resin dispersions obtained in Comparative Example 2 and 3. Figure 2 and Figure 3 Comparative explanation: Compared with Comparative Example 2, the addition of sulfonated silica nanoparticle-supported free radical quencher in Example 2 can significantly improve the chemical durability of the membrane electrode, from 325 hours to more than 500 hours. Detailed Implementation

[0021] The embodiments given below are intended to further illustrate the present invention, but should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0022] Example 1: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 50g of perfluorosulfonic acid resin (Solvay (Shanghai) Co., Ltd. Aquivion® PW-72S) with an EW value of 720g / mol, 630g of water, 200g of n-propanol, 20g of ethanol, and 100g of trifluoroethanol to a reaction vessel. Slowly introduce inert gas to purge the air from the vessel. Then set the reaction temperature to 40℃, the heating rate to 0.5℃ / min, and the stirring speed to 150r / min. After the temperature stabilizes, stir and react for 12h to allow the solvent to fully swell the resin. Maintain an inert gas atmosphere throughout the reaction process.

[0023] b. Weigh 0.5g of sulfonated silica nanoparticle-supported cerium oxide and add it to the above solution. Set the reaction temperature to 90℃, the stirring speed to 350r / min, maintain an inert gas atmosphere, and stir for 24h to obtain a perfluorosulfonic acid resin predispersant.

[0024] The preparation method of the sulfonated silica nanoparticle-supported cerium oxide is as follows: A hydrothermal-in-situ synthesis method is used. In a high-pressure reactor lined with polytetrafluoroethylene, 100 parts by weight of deionized water, 30 parts by weight of ethanol, and 1 part by weight of hexadecyltrimethylammonium bromide are added and stirred until dissolved. Then, 8 parts by weight of TEOS (tetraethyl orthosilicate) are added and stirred for 30 minutes. Next, 2 parts by weight of cerium oxide and 5 parts by weight of p-styrene sulfonic acid are added and stirred for 10 minutes to ensure uniform mixing. Ammonia is added dropwise to adjust the pH to 8-9. The reactor is sealed and reacted at 120°C for 24 hours. After the reaction, the mixture is allowed to cool naturally. The solid obtained after centrifugation is washed three times with deionized water and ethanol to remove surfactants and impurities. The washed solid is dried overnight at 60°C and then calcined at 450°C for 4 hours to remove surfactants and crystallize free radical quenchers, yielding sulfonated silica nanoparticle-supported cerium oxide.

[0025] c. Transfer the perfluorosulfonic acid resin predispersant into a high-pressure homogenizer, set the homogenization pressure to 800 bar, and homogenize 5 times to obtain a high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode with uniformly dispersed molecular chains.

[0026] Comparative Example 1: a. Add 50g of perfluorosulfonic acid resin (Solvay (Shanghai) Co., Ltd. Aquivion® PW-72S) with an EW value of 720g / mol, 630g of water, 200g of n-propanol, and 20g of ethanol to a reaction vessel. Slowly introduce inert gas to purge the air from the vessel. Then set the reaction temperature to 40℃, the heating rate to 0.5℃ / min, and the stirring speed to 150r / min. After the temperature stabilizes, stir the reaction for 12h to allow the solvent to fully swell the resin. Maintain an inert gas atmosphere throughout the reaction process.

[0027] b. Weigh 0.5g of sulfonated silica nanoparticle-supported cerium oxide and add it to the above solution. Set the reaction temperature to 90℃, the stirring speed to 350r / min, maintain an inert gas atmosphere, and stir for 24h to obtain a perfluorosulfonic acid resin predispersant.

[0028] c. Transfer the perfluorosulfonic acid resin predispersant to a high-pressure homogenizer, set the homogenization pressure to 800 bar, and homogenize 5 times to obtain the perfluorosulfonic acid resin dispersion.

[0029] Table 1: Impedance comparison of film electrodes prepared with sulfonic acid solution in Example 1 and Comparative Example 1 at different temperatures and humidity levels (Test method: Electrochemical impedance spectroscopy, EIS):

[0030] Example 2: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 80g of perfluorosulfonic acid resin (Solvay (Shanghai) Co., Ltd. Aquivion® PW-79S) with an EW value of 790g / mol, 610g of water, 130g of n-propanol, 90g of N-methylpyrrolidone, and 90g of pentafluoroethanol to a reaction vessel. Slowly introduce inert gas to purge the air from the vessel. Then set the reaction temperature to 60℃, the heating rate to 1.0℃ / min, the stirring speed to 150r / min, and stir for 18h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction.

[0031] b. Weigh 1.7g of sulfonated silica nanoparticle-supported cerium oxide and add it to the above solution. Set the reaction temperature to 120℃, the stirring speed to 450r / min, and maintain an inert gas atmosphere for stirring and reacting for 20h to obtain a perfluorosulfonic acid resin predispersant. The preparation method of cerium oxide supported on sulfonated silica nanoparticles is the same as in Example 1.

[0032] c. Transfer the perfluorosulfonic acid resin predispersant into a high-pressure homogenizer, set the homogenization pressure to 1000 bar, and homogenize 8 times to obtain a high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode with uniformly dispersed molecular chains.

[0033] Comparative Example 2: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 80g of perfluorosulfonic acid resin (Solvay (Shanghai) Co., Ltd. Aquivion® PW-79S) with an EW value of 790g / mol, 610g of water, 130g of n-propanol, 90g of N-methylpyrrolidone, and 90g of pentafluoroethanol to a reaction vessel. Slowly introduce inert gas to purge the air from the vessel. Then set the reaction temperature to 60℃, the heating rate to 1.0℃ / min, the stirring speed to 150r / min, and stir for 18h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction.

[0034] b. Weigh 1.7g of cerium oxide and add it to the above solution. Set the reaction temperature to 120℃, the stirring speed to 450r / min, and maintain an inert gas atmosphere for stirring and reacting for 20h to obtain a perfluorosulfonic acid resin predispersant.

[0035] c. Transfer the perfluorosulfonic acid resin predispersant to a high-pressure homogenizer, set the homogenization pressure to 1000 bar, and homogenize 8 times to obtain the perfluorosulfonic acid resin dispersion.

[0036] Table 2: Comparison of Ce ion loss rates in acid solutions after the membrane electrodes prepared with sulfonic acid solutions described in Example 2 and Comparative Example 2 (Test method: The membrane electrodes were immersed in 1M sulfuric acid solution, and elemental analysis was performed at intervals):

[0037] Example 3: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 100g of perfluorosulfonic acid resin with an EW value of 870g / mol (Solvay (Chemicals) Shanghai Co., Ltd. Aquivion® PW-87S), 590g of water, 135g of isopropanol, 100g of nitrogen-nitrogen dimethylformamide, and 75g of tetrafluoropropanol to a reaction vessel. Slowly introduce nitrogen gas to purge the air from the vessel. Then set the reaction temperature to 55℃, the heating rate to 1.0℃ / min, the stirring speed to 120r / min, and stir for 18h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction process.

[0038] b. After the reaction is complete, weigh 0.9g of sulfonated silica nanoparticle-supported chromium oxide and add it to the above solution. Set the reaction temperature to 135℃, the stirring speed to 400r / min, and maintain a nitrogen atmosphere for stirring and reaction for 24h to obtain a perfluorosulfonic acid resin predispersant.

[0039] The preparation method of the sulfonated silica nanoparticle-supported chromium oxide is as follows: A hydrothermal-in-situ synthesis method is used. In a high-pressure reactor lined with polytetrafluoroethylene, 90 parts by weight of deionized water, 20 parts by weight of ethanol, and 1 part by weight of hexadecyltrimethylammonium bromide are added and stirred until dissolved. Then, 8 parts by weight of TEOS (tetraethyl orthosilicate) are added and stirred for 30 minutes. Next, 2 parts by weight of chromium oxide and 5 parts by weight of p-styrene sulfonic acid are added and stirred for 10 minutes to ensure uniform mixing. Ammonia is added dropwise to adjust the pH to 8-9. The reactor is sealed and reacted at 130°C for 24 hours. After the reaction, the mixture is allowed to cool naturally. The solid obtained after centrifugation is washed three times with deionized water and ethanol to remove surfactants and impurities. The washed solid is dried overnight at 60°C and then calcined at 480°C for 3 hours to remove surfactants and crystallize free radical quenchers, yielding sulfonated silica nanoparticle-supported chromium oxide.

[0040] c. Transfer the perfluorosulfonic acid resin predispersant to a high-pressure homogenizer, set the homogenization pressure to 600 bar, and homogenize 6 times to obtain a high-performance perfluorosulfonic acid resin dispersion with uniformly dispersed molecular chains.

[0041] Table 3: Impedance comparison of the film electrode prepared by the sulfonic acid solution in Example 3 under different temperatures and humidity conditions (Test method: Electrochemical impedance spectroscopy, EIS):

[0042] Example 4: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 135g of perfluorosulfonic acid resin (Solvay (Shanghai) Co., Ltd. Aquivion® PW-98S) with an EW value of 980g / mol, 595g of water, 140g of isopropanol, 80g of nitrogen-nitrogen dimethylformamide, and 50g of pentafluoropropanol to a reaction vessel. Slowly introduce nitrogen gas to purge the air from the vessel. Then set the reaction temperature to 45℃, the heating rate to 0.5℃ / min, and the stirring speed to 150r / min. Stir and react for 24h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction process.

[0043] b. After the reaction is complete, weigh 1.25g of sulfonated silica nanoparticle-supported manganese oxide and add it to the above solution. Set the reaction temperature to 145℃, the stirring speed to 400r / min, and maintain a nitrogen atmosphere for stirring and reaction for 24h to obtain a perfluorosulfonic acid resin predispersant.

[0044] The method for preparing sulfonated silica nanoparticle-supported manganese oxide is as follows: A hydrothermal-in-situ synthesis method is used. In a high-pressure reactor lined with polytetrafluoroethylene, 120 parts by weight of deionized water, 40 parts by weight of ethanol, and 1 part by weight of hexadecyltrimethylammonium bromide are added and stirred until dissolved. Then, 8 parts by weight of TEOS (tetraethyl orthosilicate) are added and stirred for 30 minutes. Next, 2 parts by weight of manganese oxide and 5 parts by weight of p-styrene sulfonic acid are added and stirred for 10 minutes to ensure uniform mixing. Ammonia is added dropwise to adjust the pH to 8-9. The reactor is sealed and reacted at 125°C for 48 hours. After the reaction, the mixture is allowed to cool naturally. The solid obtained after centrifugation is washed three times with deionized water and ethanol to remove surfactants and impurities. The washed solid is dried overnight at 70°C and then calcined at 500°C for 2 hours to remove surfactants and crystallize free radical quenchers, yielding sulfonated silica nanoparticle-supported manganese oxide.

[0045] c. Transfer the perfluorosulfonic acid resin predispersant to a high-pressure homogenizer, set the homogenization pressure to 800 bar, and homogenize 8 times to obtain a high-performance perfluorosulfonic acid resin dispersion with uniformly dispersed molecular chains.

[0046] Table 4: Impedance comparison of the film electrode prepared by the sulfonic acid solution in Example 4 under different temperatures and humidity conditions (Test method: Electrochemical impedance spectroscopy, EIS):

[0047] Example 5: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 75g of perfluorosulfonic acid resin with an EW value of 720g / mol, 75g of perfluorosulfonic acid resin with an EW value of 980g / mol (Solvay Chemicals Shanghai Co., Ltd. Aquivion® PW-72S, PW-98S), 575g of water, 110g of isopropanol, 105g of nitrogen-nitrogen dimethylformamide, and a mixture of 60g of tetrafluoropropanol and pentafluoropropanol to a reaction vessel. Slowly introduce nitrogen gas to purge the air from the vessel. Then set the reaction temperature to 60℃, the heating rate to 1.5℃ / min, the stirring speed to 200r / min, and stir the reaction for 24h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction process.

[0048] b. Weigh 2.3g of sulfonated silica nanoparticle-supported manganese oxide and add it to the above solution. Set the reaction temperature to 155℃, the stirring speed to 400r / min, and maintain a nitrogen atmosphere for stirring and reaction for 18h to obtain a perfluorosulfonic acid resin predispersant.

[0049] The preparation method of manganese oxide supported on sulfonated silica nanoparticles is the same as in Example 4.

[0050] c. Transfer the perfluorosulfonic acid resin pre-dispersion liquid into a high-pressure homogenizer, set the homogenization pressure to 1000 bar, and homogenize 10 times to obtain a high-performance perfluorosulfonic acid resin dispersion with uniformly dispersed molecular chains.

[0051] Table 5: Impedance comparison of the film electrode prepared by the sulfonic acid solution in Example 5 under different temperatures and humidity conditions (Test method: Electrochemical impedance spectroscopy, EIS):

[0052] Example 6: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 60g of perfluorosulfonic acid resin with an EW value of 790g / mol, 80g of perfluorosulfonic acid resin with an EW value of 870g / mol (Solvay Chemicals Shanghai Co., Ltd. Aquivion® PW-79S, PW-87S), 610g of water, 105g of isopropanol, 75g of nitrogen-nitrogen dimethylformamide, and 70g of a mixture of tetrafluoropropanol and pentafluoropropanol to a reaction vessel. Slowly introduce nitrogen gas to purge the air from the vessel. Then set the reaction temperature to 65℃, the heating rate to 1.5℃ / min, and the stirring speed to 210r / min. Stir and react for 24h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction process.

[0053] b. Weigh 2.8g of sulfonated silica nanoparticle-supported manganese oxide and add it to the above solution. Set the reaction temperature to 155℃, the stirring speed to 400r / min, and maintain a nitrogen atmosphere for stirring and reaction for 18h to obtain a perfluorosulfonic acid resin predispersant.

[0054] The preparation method of manganese oxide supported on sulfonated silica nanoparticles is the same as in Example 4.

[0055] c. Transfer the perfluorosulfonic acid resin predispersant to a high-pressure homogenizer, set the homogenization pressure to 1000 bar, and homogenize 8 times to obtain a high-performance perfluorosulfonic acid resin dispersion with uniformly dispersed molecular chains.

[0056] Table 6: Impedance comparison of the film electrode prepared by the sulfonic acid solution in Example 6 under different temperatures and humidity conditions (Test method: Electrochemical impedance spectroscopy, EIS):

[0057] Example 7: A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, comprising the following steps: a. Add 100g of perfluorosulfonic acid resin with an EW value of 870g / mol, 80g of perfluorosulfonic acid resin with an EW value of 980g / mol (Solvay Chemicals Shanghai Co., Ltd. Aquivion® PW-87S, PW-98S), 620g of water, 105g of isopropanol, 85g of nitrogen-nitrogen dimethylformamide, and a mixture of 10g of tetrafluoropropanol and pentafluoropropanol to a reaction vessel. Slowly introduce nitrogen gas to purge the air from the vessel. Then set the reaction temperature to 65℃, the heating rate to 1.5℃ / min, the stirring speed to 210r / min, and stir the reaction for 24h to allow the solvent to fully swell the resin. Maintain a nitrogen atmosphere throughout the reaction process.

[0058] b. Weigh 3.4g of sulfonated silica nanoparticle-supported alumina and add it to the above solution. Set the reaction temperature to 165℃, the stirring speed to 400r / min, and maintain a nitrogen atmosphere for stirring and reaction for 20h to obtain a perfluorosulfonic acid resin predispersant.

[0059] The preparation method of the sulfonated silica nanoparticle-supported alumina is as follows: A hydrothermal-in-situ synthesis method is used. In a high-pressure reactor lined with polytetrafluoroethylene, 100 parts by weight of deionized water, 40 parts by weight of ethanol, and 1 part by weight of hexadecyltrimethylammonium bromide are added and stirred until dissolved. Then, 8 parts by weight of TEOS (tetraethyl orthosilicate) are added and stirred for 30 minutes. Next, 2 parts by weight of alumina and 5 parts by weight of p-styrene sulfonic acid are added and stirred for 10 minutes to ensure uniform mixing. Ammonia is added dropwise to adjust the pH to 8-9. The reactor is sealed and reacted at 120°C for 48 hours. After the reaction, the mixture is allowed to cool naturally. The solid obtained after centrifugation is washed three times with deionized water and ethanol to remove surfactants and impurities. The washed solid is dried overnight at 70°C and then calcined at 500°C for 4 hours to remove surfactants and crystallize free radical quenchers, yielding sulfonated silica nanoparticle-supported alumina.

[0060] c. Transfer the perfluorosulfonic acid resin predispersant to a high-pressure homogenizer, set the homogenization pressure to 1000 bar, and homogenize 6 times to obtain a high-performance perfluorosulfonic acid resin dispersion with uniformly dispersed molecular chains.

[0061] Table 7: Impedance comparison of the film electrode prepared by the sulfonic acid solution in Example 7 under different temperatures and humidity conditions (Test method: Electrochemical impedance spectroscopy, EIS):

[0062] As demonstrated in the above examples, the addition of fluorocarbon alcohol additives can break the hydrophobic aggregation between the main chains, transforming the molecular chains from a "tightly aggregated state" to a loosely dispersed state. This significantly improves the compatibility of the resin and solvent system, increases dispersion uniformity, and thus enhances the proton conductivity of the solution, thereby improving the electrochemical performance of the membrane electrode. The introduction of sulfonated silica nanoparticle-supported free radical quenchers increases the compatibility between the free radical quenchers and perfluorosulfonic acid resin, reduces agglomeration during dispersion, and the free radical quenchers are embedded on the surface of silica nanoparticles, reducing migration and loss of free radical quenchers during operation, significantly improving stability and thus significantly extending the chemical lifetime of the membrane electrode. Through formulation optimization and process innovation, this invention produces a perfluorosulfonic acid resin dispersion that can effectively improve the performance of hydrogen fuel cell membrane electrodes, possessing significant industrial application value.

[0063] In the above embodiments: unless otherwise specified, the percentage examples used are mass (weight) percentage examples or percentage examples known to those skilled in the art; unless otherwise specified, the proportions used are mass (weight) proportions; the weight parts can all be grams or kilograms.

[0064] In the above embodiments, the process parameters (temperature, time, speed, etc.) and the values ​​of each component dosage in each step are ranges, and any point can be applied.

[0065] The technical contents of this invention and the above embodiments that are not specifically described are the same as those of the prior art, and the raw materials are all commercially available products.

[0066] The present invention is not limited to the above embodiments; all embodiments described herein can be implemented and have the aforementioned good effects.

Claims

1. A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode assembly, characterized in that... Includes the following steps: a. Add perfluorosulfonic acid resin to a reaction vessel, add water, polar organic solvent, and synergistic agent fluorocarbon alcohol. Under the protection of inert gas, heat to 40-60℃ and stir for 12-24 h to allow the solvent to fully swell the perfluorosulfonic acid resin and obtain dispersion A. The fluorocarbon alcohol is one or a mixture of two or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, perfluorooctylethanol, and perfluorohexylethanol; b. Add a supported free radical quencher to the dispersion A obtained in step a, and heat it to 90-140°C under the protection of an inert gas and stir for 12-24 h to further disperse the perfluorosulfonic acid resin and fully mix it with the supported free radical quencher to obtain dispersion B. c. After transferring the dispersion B obtained in step b into a high-pressure homogenizer for homogenization, a stable and uniformly dispersed high-performance perfluorosulfonic acid resin dispersion containing a supported free radical quencher for hydrogen fuel cell membrane electrode assembly is obtained.

2. The method for preparing the high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode assembly according to claim 1, characterized in that: The supported free radical quencher mentioned in step b is one or a mixture of two or more of the following: sulfonated silica nanoparticles supported cerium oxide, sulfonated silica nanoparticles supported cerium sulfate, sulfonated silica nanoparticles supported cerium nitrate, sulfonated silica nanoparticles supported manganese oxide, sulfonated silica nanoparticles supported chromium oxide, sulfonated silica nanoparticles supported aluminum oxide, and sulfonated silica nanoparticles supported cobalt oxide.

3. The method for preparing the high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode assembly according to claim 1 or 2, characterized in that: The weight percentage ratio of the raw materials perfluorosulfonic acid resin, water, polar organic solvent, and fluorocarbon alcohol mentioned in step a is as follows: perfluorosulfonic acid resin 5%–30%, water 47%–63%, polar organic solvent 18%–22%, and fluorocarbon alcohol 5%–10%, and the total of all raw materials is 100%. The mass amount of the supported free radical quencher mentioned in step b is 0.5% to 9.5% of the mass of the perfluorosulfonic acid resin.

4. The method for preparing the high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode assembly according to claim 1 or 2, characterized in that: The perfluorinated sulfonic acid resin described in step a is composed of a polytetrafluoroethylene structure (-CF2-CF2-) as a main chain, -[OCF2C(CF3)F] m -O[CF2CF2] n -SO3H as a side chain, wherein m = 0 or 1 and n = 1 or 2.

5. The method for preparing the high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode assembly according to claim 1 or 2, characterized in that: The perfluorosulfonic acid resin product mentioned in step a is manufactured by Solvay (Chemicals) Shanghai Co., Ltd., and is one or a mixture of two or more of the following: Aquivion® PW-72S, Aquivion® PW-79S, Aquivion® PW-87S, and Aquivion® PW-98S.

6. A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode according to claim 1 or 2, characterized in that: The EW value (EW value, i.e., ion exchange equivalent) of the perfluorosulfonic acid resin mentioned in step a is 700-1000 g / mol.

7. The method for preparing the high-performance perfluorosulfonic acid resin dispersion for hydrogen fuel cell membrane electrode assembly according to claim 1 or 2, characterized in that: The polar organic solvent mentioned in step a is one or a mixture of two or more of the following: n-propanol, n-butanol, ethanol, isopropanol, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

8. A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode according to claim 1 or 2, characterized in that: The inert gas mentioned in steps a and b is one or a mixture of two or more of nitrogen, helium, and argon.

9. A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode according to claim 1 or 2, characterized in that: The heating rate in step a is 0.5℃ / min to 2℃ / min, and the stirring speed is 100 to 200 r / min; The stirring speed in step b is 300-600 r / min.

10. A method for preparing a high-performance perfluorosulfonic acid resin dispersion for a hydrogen fuel cell membrane electrode according to claim 1 or 2, characterized in that: The homogenization process in the homogenizer described in step c is carried out at a pressure of 300–1200 bar, and the number of homogenization cycles is 1–10.

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