Highly oxygen-permeable hydrogen-type fluorine-containing sulfonic acid resin, and preparation method and application thereof

Abstract

The application relates to a high-oxygen-permeability hydrogen-containing fluorosulfonic acid resin and a preparation method and application thereof, and belongs to the technical field of electrolyte materials for fuel cells. The application solves the technical problems of poor oxygen permeability and high cost of fluorosulfonic acid resin in the prior art. The preparation method comprises the following steps: polymerizing a norbornene series monomer A and a perfluorovinyl ether monomer B containing sulfonyl fluoride under the initiation of an iron complex, then soaking the obtained sulfonyl fluoride type fluorosulfonic acid resin in an alkaline solution to hydrolyze the -SO2F group into a -SO3X group, and then soaking the obtained sulfonyl fluoride type fluorosulfonic acid resin in an acidic solution to convert the -SO3X group into a -SO3H group, so as to obtain the hydrogen-containing fluorosulfonic acid resin. The preparation method of the hydrogen-containing fluorosulfonic acid resin has the advantages of mild conditions, simple operation, low production cost, good processability of the obtained hydrogen-containing fluorosulfonic acid resin in general solvents, high conductivity, good oxygen permeability and the like, and the hydrogen-containing fluorosulfonic acid resin can be applied as an electrolyte material of a cathode catalyst layer in a proton exchange membrane fuel cell.

Description

Technical Field

[0001] This invention belongs to the technical field of electrolyte materials for fuel cells, specifically relating to a highly oxygen-permeable hydrogen-form fluorosulfonic acid resin, its preparation method and application, and particularly to the application of this highly oxygen-permeable hydrogen-form fluorosulfonic acid resin as an electrolyte material for the cathode catalyst layer in a proton exchange membrane fuel cell. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) are considered one of the most promising technologies for future green energy due to their high energy conversion efficiency and zero emissions. Although PEMFC-based vehicles and backup power systems are already commercialized, their high cost significantly hinders their widespread adoption. Increasing the power density of PEMFCs is considered the most efficient way to reduce their cost, as this reduces the amount of expensive materials used, including membrane-based and platinum-based catalysts.

[0003] Research has revealed that the oxygen transport efficiency of the cathode catalyst layer (CCL) to the catalytic active sites is a key factor affecting the power density of PEMFCs during operation, especially under low platinum loading. Therefore, improving the oxygen transport efficiency of the CCL is crucial for developing high-power-density PEMFCs with low platinum loading. Using an electrolyte with excellent oxygen permeability in the CCL is one of the most effective ways to improve its oxygen transport efficiency.

[0004] In the existing technology, the mainstream commercial oxygen-permeable electrolyte material is Nafion from Chemours, Inc., with the structural formula shown in Formula I. However, this product has a low oxygen permeability, with an oxygen permeability constant of around 0.1 (cm). 3 / m.24h.0.1MPa).

[0005]

[0006] CN104220467A discloses a fluorosulfonic acid resin containing a dioxacyclopentene structure, with the structural formula shown in Formula II, and its application as an electrolyte in CCLs. In the fluorosulfonic acid resin structure, the rigid dioxacyclopentene structure provides high oxygen permeability, thereby increasing the power density of the assembled fuel cell. However, monomers containing the dioxacyclopentene structure are difficult to synthesize and expensive, hindering commercialization. Therefore, a cost-effective sulfonic acid resin with high oxygen permeability is needed.

[0007] Summary of the Invention

[0008] One of the objectives of this invention is to provide a method for preparing a hydrogen-form fluorosulfonic acid resin with high oxygen permeability, which is characterized by mild conditions, simple operation, and low production cost.

[0009] The second objective of this invention is to provide a hydrogen-form fluorosulfonic acid resin with high oxygen permeability, which has good processability in common solvents, high conductivity, and good oxygen permeability.

[0010] The third objective of this invention is to provide an application of a highly oxygen-permeable hydrogen-form fluorosulfonic acid resin as an electrolyte material for the cathode catalyst layer in a proton exchange membrane fuel cell.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] The method for preparing the highly oxygen-permeable hydrogen-form fluorosulfonic acid resin of the present invention includes the following steps:

[0013] Step 1: The monomers are polymerized at 50-100℃ using an iron complex as a catalyst for 7-12 hours. After precipitation, filtration, washing, and vacuum drying, sulfonyl fluoride type fluorosulfonic acid resin is obtained.

[0014] The reaction monomers are monomer A and monomer B, or monomer A, monomer B and monomer C;

[0015] The monomer A is selected from bicyclo[2,2,1]hept-2-ene, 1-methylbicyclo[2,2,1]hept-2-ene, 5-methylbicyclo[2,2,1]hept-2-ene, 1-ethylbicyclo[2,2,1]hept-2-ene, 5-ethylbicyclo[2,2,1]hept-2-ene or 5,5-dimethylbicyclo[2,2,1]hept-2-ene;

[0016] The structural formula of monomer B is CF2=CFO[CF2CF(CF3)O] a [CF2CF2] b SO2F, where a = 0 or 1, b = 1 or 2;

[0017] The monomer C is tetrafluoroethylene;

[0018] Step 2: Immerse the sulfonyl fluoride type fluorosulfonic acid resin in XOH solution, where X = Li, Na or K, to hydrolyze the -SO2F group into the -SO3X group. Then immerse it in an acidic solution to convert the -SO3X group into the -SO3H group. Wash until neutral and dry to obtain the hydrogen form fluorosulfonic acid resin.

[0019] Preferably, in step one, after the reactant monomer is dissolved in an organic solvent, the polymerization reaction is initiated by using an iron complex as a catalyst at 50–100°C for 7–12 hours; more preferably, the organic solvent is toluene.

[0020] Preferably, in step one, the molar ratio of monomer A to monomer B is 1:1 to 10:1, and the amount of monomer C added is <20 wt%; more preferably, the amount of monomer C added is <10 wt%; and particularly preferably, the amount of monomer C added is 2 to 10 wt%.

[0021] Preferably, in step one, when the reacting monomers are monomer A and monomer B, the reaction pressure is atmospheric pressure; when the reacting monomers are monomer A, monomer B and monomer C, the reaction pressure is 0.2 to 3.5 MPa.

[0022] Preferably, in step one, the iron complex is composed of ferric chloride and a ligand, wherein the ligand is selected from ethyl acetoacetate, diethyl malonate, 8-hydroxyquinoline, α,α'-bipyridine, o-phenanthroline, pyridine, isoquinoline, quinoline, porphyrins, ethylenediaminetetraacetic acid, ethylenediamine, diethylamine, acetylacetone, or benzoylacetone, and the molar ratio of ferric chloride to the ligand is 1:1 to 1:3;

[0023] More preferably, the molar ratio of ferric chloride to the ligand is 1:1 to 1:1.2;

[0024] More preferably, the iron complex is prepared by dissolving ferric chloride, ligand and haloalkanes in an organic solvent under an inert atmosphere, and reacting at a constant temperature of 20-100°C for 15-60 min under a sealed environment, followed by cooling to obtain the iron complex.

[0025] Particularly preferred is that the haloalkane includes benzyl bromide, benzyl chloride, 1-bromo-1-phenylethane, 1-chloro-1-phenylethane, 1-chloro-1-phenylpropane, trimethyl bromide, or trimethyl chloromethane;

[0026] Particularly preferred is that the molar ratio of the haloalkane to the ligand is 0.1:1 to 10:1;

[0027] Most preferably, the molar ratio of the haloalkane to the ligand is 0.3:1 to 3:1.

[0028] Preferably, in step one, the obtained reaction solution is poured into an acidic methanol or ethanol solution to precipitate the precipitate, and the precipitate is washed with methanol or ethanol until neutral. The acid is hydrochloric acid, nitric acid, or sulfuric acid, and the mass percentage of the acid in the acidic methanol or ethanol solution is <10 wt%. More preferably, the mass percentage of the acid is 5 wt%.

[0029] Preferably, in step one, the vacuum degree of the vacuum drying is <1000Pa, the vacuum drying temperature is 80℃, and the vacuum drying time is 12h.

[0030] Preferably, in step two, the concentration of the XOH solution is 15–30 wt%; more preferably, it is 20 wt%.

[0031] Preferably, in step two, the amount of XOH solution used is 5-20 times the weight of the sulfonyl fluoride type fluorosulfonic acid resin; more preferably, it is 10 times.

[0032] Preferably, in step two, the condition for hydrolyzing the -SO2F group into the -SO3X group is reflux heating; more preferably, the reflux temperature is 50-100°C and the time is 12-48 hours.

[0033] Preferably, in step two, the acidic solution is a nitric acid solution, a hydrochloric acid solution, or a sulfuric acid solution, more preferably a nitric acid solution.

[0034] Preferably, in step two, the concentration of acid in the acidic solution is 15-30 wt%; more preferably, it is 20 wt%.

[0035] Preferably, in step two, the conditions for converting the -SO3X group to the -SO3H group are: immersing in an acidic solution at 75-85°C for 0.5-1.5 hours, removing the solution, taking a fresh acidic solution, and immersing again in an acidic solution at 75-85°C for 0.5-1 hours, repeating this process multiple times.

[0036] More preferably, the soaking is performed 4 to 8 times in total;

[0037] Preferably, the soaking temperature is 80℃ each time, the soaking time is 1 hour each time, and a total of 5 soakings are performed.

[0038] Preferably, in step two, the mixture is washed with methanol or ethanol until it becomes neutral.

[0039] Preferably, in step two, the drying temperature is 90–100°C and the drying time is 18–30 h; more preferably, the drying temperature is 100°C and the drying time is 24 h.

[0040] Preferably, in step two, the sulfonyl fluoride type fluorosulfonic acid resin is first prepared into granules and then soaked in XOH solution;

[0041] More preferably, the sulfonyl fluoride type fluorosulfonic acid resin is first compressed into sheets and then cut into granules;

[0042] In particular, it is preferred that the material be pressed into thin sheets of 60-150 μm at 120-220°C using a flat vulcanizing machine and then cut into granules that can pass through a 50-mesh filter.

[0043] Preferably, the temperature of the flat vulcanizing machine is 150–220°C;

[0044] Particularly preferred is that it is pressed into a 100μm thin sheet;

[0045] The preferred temperature for the flat vulcanizing machine is 180–220°C.

[0046] The present invention also provides a hydrogen-form fluorosulfonic acid resin with high oxygen permeability prepared by the above preparation method.

[0047] The present invention also provides the application of the above-mentioned highly oxygen-permeable hydrogen-form fluorosulfonic acid resin as an electrolyte material for the cathode catalyst layer in a proton exchange membrane fuel cell.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] Due to the strong electronegativity of fluorine atoms and the crystallinity of fluorine-carbon molecular chains, fluorinated resins are generally insoluble in organic solvents. The high oxygen permeability hydrogen-form fluorosulfonic acid resin of the present invention contains a cyclic structure of norbornene. The hydrogen atoms of norbornene can improve the solubility of the resin in organic solvents. At the same time, the rigid cyclic structure hinders the crystallization of the molecular chains. Therefore, the hydrogen-form fluorosulfonic acid resin of the present invention has superior solubility in common solvents compared to fluorinated resins, which can improve its processability in common solvents. Furthermore, the hydrogen-form fluorosulfonic acid resin of the present invention has high electrical conductivity and good oxygen permeability (the oxygen permeability constant is more than ten times that of Nafion).

[0050] The method for preparing the highly oxygen-permeable hydrogen-form fluorosulfonic acid resin of the present invention is mild, simple to operate, and uses widely available and inexpensive raw materials, thus resulting in low production costs (the unit price of the nobornene series of raw materials is one-tenth of that of the raw materials in the preparation method in CN104220467A).

[0051] The highly oxygen-permeable hydrogen-form fluorosulfonic acid resin of the present invention can be used as an electrolyte material for the cathode catalyst layer in proton exchange membrane fuel cells. Detailed Implementation

[0052] To provide a deeper understanding of the present invention, preferred embodiments are described below to further illustrate its features and advantages. Any variations or modifications that do not depart from the spirit of the present invention will be understood by those skilled in the art. The scope of protection of the present invention is determined by the scope of the claims.

[0053] The method for preparing the highly oxygen-permeable hydrogen-form fluorosulfonic acid resin of the present invention includes the following steps:

[0054] Step 1: Monomer A and monomer B are subjected to polymerization reaction initiated by iron complex as catalyst at normal pressure and 50-100℃ for 7-12 hours. After precipitation, filtration, washing, and vacuum drying, sulfonyl fluoride type fluorosulfonic acid resin is obtained, with a conversion rate of 50-80%.

[0055] Step 2: Immerse the sulfonyl fluoride type fluorosulfonic acid resin in XOH solution, where X = K, Na or K, to hydrolyze the -SO2F group into the -SO3X group. Then immerse it in an acidic solution to convert the -SO3X group into the -SO3H group, thus obtaining the hydrogen form fluorosulfonic acid resin.

[0056] In the above technical solution, in step one, monomer A is a norbornene series monomer, selected from bicyclo[2,2,1]hept-2-ene, 1-methylbicyclo[2,2,1]hept-2-ene, 5-methylbicyclo[2,2,1]hept-2-ene, 1-ethylbicyclo[2,2,1]hept-2-ene, 5-ethylbicyclo[2,2,1]hept-2-ene, or 5,5-dimethylbicyclo[2,2,1]hept-2-ene; monomer B is a perfluorovinyl ether monomer containing sulfonyl fluoride, with the structural formula CF2=CFO[CF2CF(CF3)O] a [CF2CF2] b SO2F, where a = 0 or 1, b = 1 or 2. The molar ratio of monomer A to monomer B is preferably 1:1 to 10:1. The product prepared by polymerization of monomer A and monomer B is a binary copolymer. Based on this, monomer C, such as tetrafluoroethylene, can be added to prepare a terpolymer. The amount of monomer C added is <20 wt%, preferably <10 wt%, more preferably 2 to 10 wt%. When the reacting monomers are monomer A, monomer B, and monomer C, since monomer C is in a gaseous state, the reaction pressure increases to 0.2 to 3.5 MPa.

[0057] In the above technical solution, in step one, the reactant monomers (monomer A and monomer B) can be dissolved in an organic solvent, and then the polymerization reaction can be initiated at 50–100°C using an iron complex as a catalyst for 7–12 hours; toluene is preferred as the organic solvent. The advantage of adding an organic solvent is that the temperature fluctuation during the reaction is narrowed and easier to control, but the reaction yield will decrease.

[0058] In the above technical solution, in step one, the structure of the iron complex is composed of ferric chloride and a ligand, wherein the ligand is selected from one of ethyl acetoacetate, diethyl malonate, 8-hydroxyquinoline, α,α'-bipyridine, o-phenanthroline, pyridine, isoquinoline, quinoline, porphyrins, ethylenediaminetetraacetic acid, ethylenediamine, diethylamine, acetylacetone, and benzoylacetone. The molar ratio of ferric chloride to the ligand is 1:1 to 1:3, more preferably 1:1 to 1:1.2. The iron complex is prepared as follows: Under an inert atmosphere, ferric chloride, the ligand, and the haloalkane are dissolved in an organic solvent. The mixture is then reacted at a constant temperature of 20–100°C for 15–60 min, preferably 70°C for 40 min, under sealed conditions. After cooling, the iron complex is obtained. The haloalkane preferably includes benzyl bromide, benzyl chloride, 1-bromo-1-phenylethane, 1-chloro-1-phenylethane, 1-chloro-1-phenylpropane, trimethylbromomethane, or trimethylchloromethane. The molar ratio of the haloalkane to the ligand is 0.1:1–10:1, preferably 0.3:1–3:1. There are no special limitations on the organic solvent; it can be used to dissolve both ferric chloride and the ligand, such as cyclohexanone or anisole.

[0059] In the above technical solution, in step one, the obtained reaction solution can be poured into an acidic methanol or ethanol solution to precipitate the precipitate. The precipitate is washed with methanol or ethanol until neutral. The acid is hydrochloric acid, nitric acid, or sulfuric acid. The mass percentage of the acid in the acidic methanol or ethanol solution is <10 wt%, preferably 5 wt%.

[0060] In the above technical solution, in step one, the preferred vacuum drying temperature is <1000Pa, the vacuum drying temperature is 80℃, and the vacuum drying time is 12h.

[0061] In the above technical solution, in step two, the concentration of the XOH solution is 15-30 wt%, preferably 20 wt%; the amount of XOH solution used is 5-20 times the weight of the sulfonyl fluoride type fluorosulfonic acid resin, preferably 10 times; the condition for hydrolyzing the -SO2F group to the -SO3X group is heating under reflux at a temperature of 50-100°C for 12-48 hours (generally, higher temperatures result in shorter times, and lower temperatures in longer times); the acidic solution is nitric acid, hydrochloric acid, or sulfuric acid, preferably nitric acid; the concentration of acid in the acidic solution is 15-30 wt%, preferably 20 wt%; the condition for converting the -SO3X group to the -SO3H group is immersion in an acidic solution at 75-85°C for 0.5-1.5 hours, followed by removal, application of a fresh acidic solution, and immersion again in an acidic solution at 75-85°C for 0.5-1 hours, repeated multiple times, preferably 4-8 times, more preferably 5 times. The solution is then washed with methanol or ethanol until neutral. The drying temperature is 90–100℃, and the drying time is 18–30 h; preferably, the drying temperature is 100℃ and the drying time is 24 h.

[0062] In the above technical solution, in step two, the sulfonyl fluoride type fluorosulfonic acid resin is first prepared into granules and then soaked in XOH solution; preferably, the sulfonyl fluoride type fluorosulfonic acid resin is first pressed into sheets and then cut into granules; more preferably, it is pressed into thin sheets of 60-150μm at 180-220℃ using a flat vulcanizing machine and then cut into granules that can pass through a 50-mesh filter; the temperature of the flat vulcanizing machine is preferably 150-220℃, more preferably 180-220℃; the sheet thickness is preferably 100μm.

[0063] The hydrogen-form fluorosulfonic acid resin prepared by the above method has excellent processability in common solvents, high electrical conductivity, and good oxygen permeability (the oxygen permeability constant is more than ten times that of Nafion).

[0064] The highly oxygen-permeable hydrogen-form fluorosulfonic acid resin of the present invention can be used as an electrolyte material for the cathode catalyst layer in a proton exchange membrane fuel cell, particularly a solid polymer fuel cell.

[0065] The terminology used in this invention generally has the meanings commonly understood by those skilled in the art, unless otherwise stated. Atmospheric pressure is 1 atmosphere.

[0066] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to embodiments.

[0067] In the following embodiments, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, apparatus, instruments, equipment, etc., used in the following embodiments are commercially available.

[0068] Example 1

[0069] Step 1: Dissolve 0.01 mol ferric chloride, 0.01 mol 8-hydroxyquinoline and 0.01 mol 1-bromo-1-phenylethane in 20 mL cyclohexanone, place the solution in a single-necked glass bottle that has been evacuated and purged with nitrogen multiple times, seal the bottle opening with a latex tube, and keep it at a constant temperature of 70°C for 40 min. After cooling, the iron complex A is obtained.

[0070] Step 2: Add 0.024 mol of bicyclo[2,2,1]hept-2-ene and 0.024 mol of monomer CF2=CFOCF2CF(CF3)OCF2CF2SO2F to a single-necked flask purged with nitrogen to obtain a mixture. Inject 1.5 mL of iron complex A into the mixture using a syringe. Place the flask in a constant temperature water bath and react at 80℃ for 7 h. Pour the product into a methanol solution containing 5 wt% hydrochloric acid to precipitate the precipitate, and wash the precipitate with methanol until neutral. Then, vacuum dry the precipitate and weigh it to obtain a sulfonyl fluoride type fluorosulfonic acid resin. The reaction yield (based on the total amount of all polymerizable monomers) is 70.3%.

[0071] Step 3: The sulfonyl fluoride type fluorosulfonic acid resin is pressed into 100μm sheets using a flat vulcanizing machine at 180-220℃. The sheet resin is then cut into granules and immersed in a 20wt% potassium hydroxide solution, heated under reflux for 12 hours. This hydrolyzes the -SO2F groups in the resin, converting them into -SO3K groups. Next, the resin is immersed five times in a 20wt% nitric acid solution at 80℃, for 1 hour each time, thereby converting the -SO3K groups in the resin into -SO3H groups, thus obtaining the hydrogen-form fluorosulfonic acid resin.

[0072] Example 2

[0073] Step 1: Dissolve 0.01 mol ferric chloride, 0.03 mol α,α'-bipyridine and 0.01 mol 1-bromo-1-phenylethane in 20 mL anisole, place the solution in a single-necked glass bottle that has been evacuated and purged with nitrogen multiple times, seal the bottle neck with a latex tube, and keep it at a constant temperature of 70°C for 40 min. After cooling, the iron complex B is obtained.

[0074] Step 2: Add 0.072 mol of 1-methylbicyclo[2,2,1]hept-2-ene and 0.024 mol of monomer CF2=CFOCF2CF(CF3)OCF2CF2SO2F to a nitrogen-filled single-necked flask to obtain a mixture. Inject 1.5 ml of iron complex B into the mixture using a syringe. Place the flask in a constant temperature water bath and react at 80°C for 7 h. Pour the product into a methanol solution containing 5 wt% hydrochloric acid to precipitate the product. Wash the precipitate with methanol until neutral. Then, vacuum dry the product and weigh it to calculate the reaction yield (based on the total amount of polymerizable monomers) as 72.1%.

[0075] Step 3 is the same as in Example 1.

[0076] Example 3

[0077] Step 1: Dissolve 0.10 mol ferric chloride, 0.01 mol α,α'-bipyridine and 0.01 mol 1-bromo-1-phenylethane in 20 mL cyclohexanone, place the solution in a single-necked glass bottle that has been purged with nitrogen multiple times, seal the bottle neck with a latex tube, and keep it at a constant temperature of 70°C for 40 min. After cooling, the iron complex C is obtained.

[0078] Step 2: Add 0.24 mol of 5-methylbicyclo[2,2,1]hept-2-ene and 0.024 mol of monomer CF2=CFOCF2CF(CF3)OCF2CF2SO2F to a nitrogen-filled single-necked flask, and dissolve in 15 mL of toluene to obtain a mixture. Inject 1 mL of the iron complex C into the mixture using a syringe. Place the flask in a constant temperature water bath and react at 70 °C for 7 h. Pour the product into a methanol solution containing 5 wt% hydrochloric acid to precipitate the polymer. Wash the precipitate with methanol until neutral. Then, vacuum dry and weigh to calculate the reaction yield (based on the total amount of polymerized monomers) as 61.3%.

[0079] Step 3 is the same as in Example 1.

[0080] Comparative Example 1 (Nafion, the electrolyte material for the cathode catalyst layer of a commercial fuel cell)

[0081] After cleaning and drying the high-pressure reactor, evacuate it and purge it with nitrogen until the moisture content is below 100 ppm and the oxygen content is below 20 ppm. After evacuation, the pressure of tetrafluoroethylene monomer was increased to 0.1 MPa. Then, 490 g of monomer CF2=CFOCF2CF(CF3)OCF2CF2SO2F was added to the reactor. The temperature was raised to 80°C, and tetrafluoroethylene monomer was introduced until the pressure reached 3 MPa. 10 mL of a trifluorotrichloroethane solution containing 0.005 g of perfluorobutyryl peroxide compound (CF3CF2CF2CO-O-OCCF2CF2CF3 (initiator)) was added using a metering pump. The reaction pressure was maintained at 3 MPa. When the amount of tetrafluoroethylene monomer added reached 150 g, the reaction was stopped, and the unreacted tetrafluoroethylene monomer was recovered. The material was discharged and transferred to a glass flask. The solid and liquid were separated by filtration and washed with methanol and deionized water. The product was further dried at 120°C for 24 h to obtain a dry sulfonyl fluoride type perfluorosulfonic acid resin. The subsequent operation was the same as step three of Example 1.

[0082] The sulfonic acid resins prepared in Examples 1-3 and Comparative Example 1 were tested. Ion exchange equivalent (EW) was tested according to GB / T 20042.3, and oxygen permeability was tested according to GB / T 19789. The test results are shown in Table 1.

[0083] Table 1. Test results of the sulfonic acid resins prepared in Examples 1-3 and Comparative Example 1.

[0084]

[0085] Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the embodiments. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing hydrogen-form fluorosulfonic acid resin, characterized in that, Includes the following steps: Step 1: The monomers are polymerized at 50-100℃ using an iron complex as a catalyst for 7-12 hours. After precipitation, filtration, washing, and vacuum drying, sulfonyl fluoride type fluorosulfonic acid resin is obtained. The reaction monomers are monomer A and monomer B; The monomer A is selected from bicyclo[2,2,1]hept-2-ene, 1-methylbicyclo[2,2,1]hept-2-ene, 5-methylbicyclo[2,2,1]hept-2-ene, 1-ethylbicyclo[2,2,1]hept-2-ene, 5-ethylbicyclo[2,2,1]hept-2-ene or 5,5-dimethylbicyclo[2,2,1]hept-2-ene; The structural formula of monomer B is CF2=CFO[CF2CF(CF3)O] a [CF2CF2] b SO2F, where a = 0 or 1, b = 1 or 2; The molar ratio of monomer A to monomer B is 1:1 to 10:1; Step 2: Immerse the sulfonyl fluoride type fluorosulfonic acid resin in XOH solution, where X = Li, Na or K, to hydrolyze the -SO2F group into the -SO3X group. Then immerse it in an acidic solution to convert the -SO3X group into the -SO3H group. Filter, wash until neutral, and dry to obtain the hydrogen form fluorosulfonic acid resin.

2. The method for preparing hydrogen-form fluorosulfonic acid resin according to claim 1, characterized in that, In step one, the reactant monomer is dissolved in an organic solvent, and then an iron complex is used as a catalyst to initiate the polymerization reaction at 50-100°C for 7-12 hours. The organic solvent is toluene.

3. The method for preparing hydrogen-form fluorosulfonic acid resin according to claim 1, characterized in that, In step one, the iron complex is composed of ferric chloride and a ligand. The ligand is selected from ethyl acetoacetate, diethyl malonate, 8-hydroxyquinoline, α,α'-bipyridine, o-phenanthroline, pyridine, isoquinoline, quinoline, porphyrins, ethylenediaminetetraacetic acid, ethylenediamine, diethylamine, acetylacetone, or benzoylacetone. The molar ratio of ferric chloride to the ligand is 1:1 to 1:

3.

4. The method for preparing hydrogen-form fluorosulfonic acid resin according to claim 3, characterized in that, The iron complex is prepared by dissolving ferric chloride, ligand and haloalkanes in an organic solvent under an inert atmosphere, and reacting at a constant temperature of 20-100℃ for 15-60 min under a sealed environment, followed by cooling to obtain the iron complex. The halogenated hydrocarbons include benzyl bromide, benzyl chloride, 1-bromo-1-phenylethane, 1-chloro-1-phenylethane, 1-chloro-1-phenylpropane, trimethyl bromide, or trimethyl chloromethane; The molar ratio of the haloalkane to the ligand is 0.1:1 to 10:

1.

5. The method for preparing hydrogen-form fluorosulfonic acid resin according to claim 1, characterized in that, In step one, the obtained reaction solution is poured into an acidic methanol or ethanol solution to precipitate the precipitate. The precipitate is washed with methanol or ethanol until neutral. The acid is hydrochloric acid, nitric acid, or sulfuric acid. The mass percentage of the acid in the acidic methanol or ethanol solution is <10 wt%.

6. The method for preparing hydrogen-form fluorosulfonic acid resin according to claim 1, characterized in that, In step two, The concentration of the XOH solution is 15-30 wt%, and the amount of XOH solution used is 5-20 times the weight of the sulfonyl fluoride type fluorosulfonic acid resin. The -SO2F group is hydrolyzed into the -SO3X group by heating and reflux. The heating and reflux temperature is 50-100℃, and the time is 12h-48h. The acidic solution is a nitric acid solution, hydrochloric acid solution, or sulfuric acid solution, and the concentration of acid in the acidic solution is 15-30 wt%. The conditions for converting the -SO3X group to the -SO3H group are: immerse in an acidic solution at 75-85℃ for 0.5-1.5 hours, remove, take a fresh acidic solution, and immerse again in an acidic solution at 75-85℃ for 0.5-1 hours, repeating this process multiple times. Wash with methanol or ethanol until neutral; The drying temperature is 90–100°C, and the drying time is 18–30 hours.

7. The method for preparing hydrogen-form fluorosulfonic acid resin according to claim 1, characterized in that, In step two, the sulfonyl fluoride type fluorosulfonic acid resin is first pressed into thin sheets of 60-150 μm at 120-220℃ using a flat vulcanizing machine, then cut into granules, and then soaked in XOH solution.

8. The hydrogen-form fluorosulfonic acid resin prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the hydrogen-form fluorosulfonic acid resin according to claim 8 as an electrolyte material for the cathode catalyst layer in a proton exchange membrane fuel cell.

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