A sulfonated PEEK film for hydrogen fuel cells and a method for preparing the same

Abstract

The application discloses a sulfonated PEEK film for hydrogen fuel cells and a preparation method thereof, and belongs to the field of film materials for batteries. The sulfonated PEEK film for hydrogen fuel cells is prepared from raw materials containing the following components in parts by mass: 100 parts of sulfonated PEEK; and 3-7 parts of PEI grafted silica fillers. The PEI grafted silica fillers are prepared by reacting PEI and sulfonated silica under the crosslinking action of a fatty diamine, and the mass ratio of PEI, sulfonated silica and the fatty diamine is 1:(1.1-1.5):(0.3-0.5). The application has the effect of improving the stability of the sulfonated PEEK.

Description

TECHNICAL FIELD

[0001] The application relates to the field of thin film materials for batteries, in particular to a sulfonated PEEK thin film for hydrogen fuel cells and a preparation method thereof. BACKGROUND

[0002] Sulfonated PEEK, namely sulfonated polyether ether ketone, is a special engineering plastic obtained by modifying polyether ether ketone through sulfonation, and can be used as a proton exchange membrane for hydrogen fuel cells.

[0003] A hydrogen fuel cell needs a high-efficiency proton-conducting membrane to realize the conduction of protons, so as to promote the electrochemical reaction of the cell. The sulfonated PEEK has good proton conduction performance, and the sulfonic acid group thereof can provide a proton conduction channel, thereby effectively improving the output power and efficiency of the fuel cell. Compared with the traditional perfluorosulfonic acid proton exchange membrane, the sulfonated PEEK has relatively low price and good chemical stability.

[0004] Since the proton exchange membrane is in contact with the electrolyte solution in the cell for a long time, it is required to have high stability, and the current sulfonated PEEK is prone to swelling in the solution, and thus is difficult to meet the stability requirement. SUMMARY

[0005] In order to improve the stability of the sulfonated PEEK, the application provides a sulfonated PEEK thin film for hydrogen fuel cells and a preparation method thereof.

[0006] In a first aspect, the application provides a sulfonated PEEK thin film for hydrogen fuel cells, which is prepared from raw materials containing the following components by mass:

[0007] 100 parts of sulfonated PEEK;

[0008] 3-7 parts of PEI-grafted silica filler;

[0009] The PEI-grafted silica filler is prepared by reacting PEI and sulfonated silica under the cross-linking action of aliphatic diamine, and the mass ratio of the PEI, the sulfonated silica and the aliphatic diamine is 1:(1.1-1.5):(0.3-0.5).

[0010] By using the above technical scheme, the silica plays a filling and reinforcing role on the internal structure of the sulfonated PEEK, so that the mechanical properties of the sulfonated PEEK are improved, the swelling property is reduced, and the stability of the sulfonated PEEK thin film in the solution is improved.

[0011] Since the silica and the sulfonated PEEK are inorganic phase and organic phase respectively, the interface bonding force is weak, which affects the dispersion of the silica. Therefore, the silica is grafted with PEI, i.e. polyetherimide, which has good interface compatibility with the sulfonated PEEK, so as to reduce the agglomeration of the silica and enhance the structure of the silica and the sulfonated PEEK. The sulfonated silica can not only realize the grafting of the silica and the PEI through the cross-linking effect of the aliphatic diamine, but also improve the interface compatibility of the silica and the sulfonated PEEK by the sulfonic acid groups after the grafting. Finally, in addition to improving the stability of the sulfonated PEEK film in the solution, the sulfonated PEEK film can also improve the proton conductivity and the high-temperature resistance.

[0012] Optionally, the sulfonated silica is obtained by reacting the silica with a thiol-containing silane coupling agent to obtain thiol-containing silica, and then performing oxidation reaction on the thiol-containing silica to obtain the sulfonated silica. The mass ratio of the silica to the thiol-containing silane coupling agent is 1:(0.05-0.09).

[0013] By adopting the above technical solution, the thiol-containing silane coupling agent introduces -SH groups on the surface of the silica. Under the action of an oxidant such as hydrogen peroxide, the -SH groups are oxidized to generate sulfonic acid groups, thereby realizing the sulfonation of the silica.

[0014] Optionally, the thiol-containing silane coupling agent includes one or both of 3-mercaptopropyl trimethoxysilane and 3-mercaptopropyl triethoxysilane.

[0015] By adopting the above technical solution, the silane of 3-mercaptopropyl trimethoxysilane and 3-mercaptopropyl triethoxysilane can react with the surface hydroxyl groups of the silica, so as to introduce the thiol groups onto the surface of the silica, and then generate the sulfonic acid groups after subsequent oxidation.

[0016] Optionally, the silica is prepared from tetraethyl orthosilicate by using polystyrene microspheres as a template, and then aging and calcining by a sol-gel method.

[0017] By adopting the above technical solution, the sol-gel method is used to prepare the silica which is fine and uniform. The polystyrene microspheres are used as the template to control the internal morphology of the silica, so as to make the silica have a mesoporous structure, promote sulfonation, and help the grafting and coating of PEI, and finally enhance the selectivity, the proton conductivity and the high-temperature resistance of the sulfonated PEEK film.

[0018] Optionally, the aliphatic diamine includes one or both of ethylenediamine and butanediamine.

[0019] By adopting the above technical solution, the ethylenediamine and the butanediamine have moderate lengths of structures, and are suitable for being used as the cross-linking agent to connect the PEI and the silica.

[0020] In a second aspect, the application provides a sulfonated PEEK film for hydrogen fuel cells, which adopts the following technical scheme:

[0021] A preparation method of a sulfonated PEEK film for hydrogen fuel cells, comprising the following steps:

[0022] The PEI is dissolved in a first solvent, and after being uniformly dissolved, sulfonated silicon dioxide is added, and the mixture is uniformly stirred and dispersed, and then a fatty diamine is added, and after continuous stirring, the mixture is filtered to obtain a PEI grafted silicon dioxide filler.

[0023] The sulfonated PEEK is dissolved in a second solvent, and after being uniformly dissolved, the PEI grafted silicon dioxide filler is added, and the mixture is uniformly stirred and dispersed, and then defoamed, coated on a substrate, and dried to remove the first solvent to obtain a sulfonated PEEK film.

[0024] By adopting the above technical scheme, the fatty diamine is used to connect the PEI and the silicon dioxide to realize grafting. Moreover, the solution casting method is used to prepare the sulfonated PEEK film, which is simple in operation and is helpful to the full dispersion of the PEI grafted silicon dioxide filler.

[0025] Optionally, the first solvent and the second solvent can be polar aprotic solvents, and specifically can be one or more of N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide.

[0026] Optionally, the preparation method of the sulfonated silicon dioxide comprises the following steps:

[0027] The silicon dioxide is dispersed in a third solvent, a thiol-containing silane coupling agent is added, and the mixture is reacted under heating, and after the reaction is completed, the mixture is filtered to collect the solid, and then the solid is put into an oxidizing agent solution to react, and after the reaction is completed, the mixture is filtered to obtain sulfonated silicon dioxide.

[0028] By adopting the above technical scheme, the thiol group is introduced by using the silane coupling agent, and then oxidized into a sulfonic acid group, so as to improve the stability of the sulfonic acid group on the surface of the silicon dioxide.

[0029] Optionally, the third solvent can be a mixed solvent of alcohol and water.

[0030] Optionally, the oxidizing agent solution is a hydrogen peroxide solution.

[0031] Optionally, the preparation method of the silicon dioxide comprises the following steps:

[0032] The tetraethyl orthosilicate is added into an alcohol and water mixed solvent containing a catalyst, and the mixture is stirred and hydrolyzed, and then evaporated under heating to obtain a gel, which is dried and calcined to obtain silicon dioxide.

[0033] Optionally, the preparation method of the silicon dioxide comprises the following steps:

[0034] The polystyrene microspheres are soaked in an alcohol and water mixed solvent, a catalyst is added, then tetraethyl orthosilicate is added, stirring hydrolysis, heating and evaporation to obtain a solid, drying, calcination, to obtain silica.

[0035] By using the above technical scheme, the polystyrene microspheres are used as a template to prepare the mesoporous structure silica.

[0036] Optionally, the particle size of the polystyrene microspheres is 50-80 nm.

[0037] In summary, the present application has the following beneficial effects:

[0038] 1. The silica in the present application plays a filling and reinforcing role on the internal structure of the sulfonated PEEK, so that the mechanical properties of the sulfonated PEEK are improved, the swelling is reduced, the stability of the sulfonated PEEK film in the solution is improved, the silica is grafted with PEI, the interface compatibility of PEI and the sulfonated PEEK is good, so that the agglomeration of the silica is reduced, and the structure of the silica and the sulfonated PEEK is enhanced. By using sulfonated silica, the grafting of silica and PEI can be realized through the crosslinking effect of aliphatic diamines, the sulfonic acid groups remaining after grafting can also improve the interface compatibility of silica and sulfonated PEEK, and finally the stability of the sulfonated PEEK film in the solution is improved, and the proton conductivity and high temperature resistance of the sulfonated PEEK film are also improved.

[0039] 2. The mesoporous silica is further used in the present application, the polystyrene microspheres are used as a template to control the internal morphology of the silica, the silica is in a mesoporous structure, the sulfonation is promoted, the PEI grafting and coating are facilitated, and the selectivity, proton conductivity and high temperature resistance of the sulfonated PEEK film are enhanced. DETAILED DESCRIPTION

[0040] The present application is further described below in detail.

[0041] Preparation Example 1

[0042] The preparation method of the sulfonated PEEK includes the following steps:

[0043] The PEEK powder of the model 770 of Zhongyan High Polymer is gradually poured into 98wt% concentrated sulfuric acid, the mass ratio of the PEEK powder to the concentrated sulfuric acid is 1:20, the PEEK powder is dissolved by continuous stirring, then the water bath is heated to 40℃, and the sulfonation is continued for 7h. After the sulfonation is completed, ice water is added, and the stirring is continued for 12h. The precipitate is collected by filtration, and the precipitate is washed with water until the pH approaches neutral. The precipitate is dried to obtain the sulfonated PEEK.

[0044] Preparation Example 2

[0045] The preparation method of the silica includes the following steps:

[0046] Ethanol and water were prepared into a mixed solvent, in which the mass percentage of ethanol was 90%, hydrochloric acid was added into the mixed solvent as a catalyst to make the pH of the mixed solvent 4. Tetraethyl orthosilicate was gradually added, the molar ratio of water to tetraethyl orthosilicate was 2, and the hydrolysis was stirred for 24 h, then heated and evaporated to obtain a gel, the gel was dried at 65 ℃ for 12 h to obtain a powder, and the powder was calcined at 550 ℃ for 4 h to obtain silica.

[0047] Preparation Example 3

[0048] A method for preparing silica, comprising the following steps:

[0049] Ethanol and water were prepared into a mixed solvent, in which the mass percentage of ethanol was 90%, polystyrene microspheres were dispersed in the mixed solvent and soaked for 12 h, then hydrochloric acid was added into the mixed solvent as a catalyst to make the pH of the mixed solvent 4. Tetraethyl orthosilicate was gradually added, the molar ratio of water to tetraethyl orthosilicate was 2, and the hydrolysis was stirred for 24 h, then heated and evaporated to obtain a solid, the solid was dried at 65 ℃ for 6 h, and the solid was calcined at 600 ℃ for 5 h to obtain silica.

[0050] Preparation Example 1

[0051] A method for preparing sulfonated silica, comprising the following steps:

[0052] The silica prepared in Preparation Example 2 was dispersed in a 92 wt% ethanol solution, 3-mercaptopropyltrimethoxysilane was added, the mass ratio of silica to 3-mercaptopropyltrimethoxysilane was 1:0.05, and the reaction was carried out at 65 ℃ for 2 h. After the reaction was completed, the solid was collected by filtration, and then the solid was put into a 20 wt% hydrogen peroxide solution for reaction at room temperature for 12 h. After the reaction was completed, the solid was collected by filtration, washed, and dried to obtain sulfonated silica.

[0053] Preparation Example 2

[0054] A method for preparing sulfonated silica, comprising the following steps:

[0055] The silica prepared in Preparation Example 3 was dispersed in a 92 wt% ethanol solution, 3-mercaptopropyltrimethoxysilane was added, the mass ratio of silica to 3-mercaptopropyltrimethoxysilane was 1:0.05, and the reaction was carried out at 65 ℃ for 2 h. After the reaction was completed, the solid was collected by filtration, and then the solid was put into a 20 wt% hydrogen peroxide solution for reaction at room temperature for 12 h. After the reaction was completed, the solid was collected by filtration, washed, and dried to obtain sulfonated silica.

[0056] Preparation Example 3

[0057] A method for preparing sulfonated silica, comprising the following steps:

[0058] The silica prepared in Preparation Example 3 was dispersed in a 92 wt% ethanol solution, 3-mercaptopropyltrimethoxysilane was added, the mass ratio of silica to 3-mercaptopropyltrimethoxysilane was 1:0.09, and the mixture was reacted at 65°C for 2 h. After the reaction was completed, the solid was collected by filtration, and the solid was then placed in a 20 wt% hydrogen peroxide solution and reacted at room temperature for 12 h. After the reaction was completed, the solid was collected by filtration, washed, and dried to obtain sulfonated silica.

[0059] Example 1

[0060] A method for preparing a sulfonated PEEK film for a hydrogen fuel cell, comprising the steps of:

[0061] 1 kg of sulfonated PEEK prepared in Preparation Example 1, 0.1 kg of PEI of Sabic grade 1000, 0.11 kg of sulfonated silica prepared in Preparation Example 1, and 0.03 kg of ethylenediamine were weighed.

[0062] The PEI was dissolved in 1 L of N,N-dimethylacetamide, and the sulfonated silica was added after the PEI was uniformly dissolved. The mixture was continuously stirred for 20 min to uniformly disperse the sulfonated silica, and then ethylenediamine was added. After the mixture was continuously stirred at 35°C for 12 h, the mixture was filtered to obtain PEI-grafted silica filler.

[0063] The sulfonated PEEK was dissolved in 10 L of N,N-dimethylacetamide, and the PEI-grafted silica filler of 0.03 kg was added after the sulfonated PEEK was uniformly dissolved. The mixture was continuously stirred for 20 min to uniformly disperse the PEI-grafted silica filler, and then the mixture was vacuum-deaerated. The obtained slurry was coated on a release substrate, and the coated substrate was dried at 70°C for 24 h to remove N,N-dimethylacetamide. The obtained film was immersed in dilute sulfuric acid and water for 24 h, respectively. After the immersion, the film was removed to obtain a sulfonated PEEK film having a thickness of 60 µm.

[0064] Example 2

[0065] A method for preparing a sulfonated PEEK film for a hydrogen fuel cell, comprising the steps of:

[0066] 1 kg of sulfonated PEEK prepared in Preparation Example 1, 0.1 kg of PEI of Sabic grade 1000, 0.15 kg of sulfonated silica prepared in Preparation Example 1, and 0.05 kg of ethylenediamine were weighed.

[0067] The PEI was dissolved in 1 L of N,N-dimethylacetamide, and the sulfonated silica was added after the PEI was uniformly dissolved. The mixture was continuously stirred for 20 min to uniformly disperse the sulfonated silica, and then ethylenediamine was added. After the mixture was continuously stirred at 35°C for 12 h, the mixture was filtered to obtain PEI-grafted silica filler.

[0068] Sulfonated PEEK was dissolved in 10 L of N,N-dimethylacetamide, and after being uniformly dissolved, 0.07 kg of PEI grafted silica filler was added, and uniform dispersion was maintained by continuous stirring for 20 min. Vacuum degassing was performed, and the obtained slurry was coated on a release substrate. Drying was performed at 70°C for 24 h to remove N,N-dimethylacetamide. The obtained film was immersed in dilute sulfuric acid and water for 24 h, respectively. After immersion, the film was removed to obtain a sulfonated PEEK film having a thickness of 60 μm.

[0069] Example 3

[0070] A method for preparing a sulfonated PEEK film for a hydrogen fuel cell, comprising the steps of:

[0071] Sulfonated PEEK prepared in Preparation Example 1 was weighed at 1 kg, PEI of SABIC brand No. 1000 was weighed at 0.1 kg, sulfonated silica prepared in Preparation Example 1 was weighed at 0.14 kg, and ethylenediamine was weighed at 0.4 kg.

[0072] PEI was dissolved in 1 L of N,N-dimethylacetamide, and after being uniformly dissolved, sulfonated silica was added. Uniform dispersion was maintained by continuous stirring for 20 min, and ethylenediamine was added. After continuous stirring at 35°C for 12 h, filtration was performed to obtain PEI grafted silica filler.

[0073] Sulfonated PEEK was dissolved in 10 L of N,N-dimethylacetamide, and after being uniformly dissolved, 0.05 kg of PEI grafted silica filler was added, and uniform dispersion was maintained by continuous stirring for 20 min. Vacuum degassing was performed, and the obtained slurry was coated on a release substrate. Drying was performed at 70°C for 24 h to remove N,N-dimethylacetamide. The obtained film was immersed in dilute sulfuric acid and water for 24 h, respectively. After immersion, the film was removed to obtain a sulfonated PEEK film having a thickness of 60 μm.

[0074] Example 4

[0075] A method for preparing a sulfonated PEEK film for a hydrogen fuel cell.

[0076] This example is different from Example 3 in that sulfonated silica is prepared in Preparation Example 2.

[0077] Example 5

[0078] A method for preparing a sulfonated PEEK film for a hydrogen fuel cell.

[0079] This example is different from Example 3 in that sulfonated silica is prepared in Preparation Example 3.

[0080] Comparative Example 1

[0081] A method for preparing a sulfonated PEEK film, comprising the steps of:

[0082] 1 kg of the sulfonated PEEK prepared in Preparation Example 1 was dissolved in 10 L of N,N-dimethylacetamide, and the resulting slurry was coated on a release substrate, and dried at 70°C for 24 hours to remove the N,N-dimethylacetamide. The resulting film was immersed in dilute sulfuric acid and water for 24 hours each, and then the film was removed to obtain a sulfonated PEEK film having a thickness of 60 μm.

[0083] Comparative Example 2

[0084] A method of preparing a sulfonated PEEK film, comprising the steps of:

[0085] 1 kg of the sulfonated PEEK prepared in Preparation Example 1, 0.018 kg of PEI of Sabic grade 1000, and 0.025 kg of the silica prepared in Preparation Example 2 were weighed.

[0086] The sulfonated PEEK was dissolved in 10 L of N,N-dimethylacetamide, and the resulting slurry was coated on a release substrate, and dried at 70°C for 24 hours to remove the N,N-dimethylacetamide. The resulting film was immersed in dilute sulfuric acid and water for 24 hours each, and then the film was removed to obtain a sulfonated PEEK film having a thickness of 60 μm.

[0087] Comparative Example 3

[0088] A method of preparing a sulfonated PEEK film, comprising the steps of:

[0089] 1 kg of the sulfonated PEEK prepared in Preparation Example 1, 0.018 kg of PEI of Sabic grade 1000, and 0.025 kg of the silica prepared in Preparation Example 2 were weighed.

[0090] The sulfonated PEEK was dissolved in 10 L of N,N-dimethylacetamide, and the resulting slurry was coated on a release substrate, and dried at 70°C for 24 hours to remove the N,N-dimethylacetamide. The resulting film was immersed in dilute sulfuric acid and water for 24 hours each, and then the film was removed to obtain a sulfonated PEEK film having a thickness of 60 μm.

[0091] Performance Test

[0092] The sulfonated PEEK films prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to the following tests.

[0093] Swelling Test: The film was cut into a test sample having a length and width of 2 cm each, and two test samples were prepared. The original length L0of the test sample was measured. d The test sample was immersed in water at 25°C and 70°C for 12 hours each, and then removed and dried. The length L of the test sample was measured. w The swelling ratio was calculated according to the formula: Swelling ratio = (L w -L d ) / L0.d The swelling rate of the film is calculated.

[0094] Vanadium ion permeation test: The film is placed between two half-pools, 1 mol / L VOSO4+ 2 mol / L H2SO4 mixed solution is added to the left half-pool, and an equal volume of 1 mol / L MgSO4+ 2 mol / L H2SO4 is added to the right half-pool. The absorbance of the right half-pool after 24 hours of test is measured by a spectrophotometer, and then the vanadium ion concentration is calculated.

[0095] Proton conductivity test: The resistance R of the film is tested by an electrochemical test system, and the thickness L and area S of the film are measured. According to σ = L / (S·R), the proton conductivity σ of the film is calculated.

[0096] The above test results are shown in Table 1.

[0097] Table 1

[0098]

[0099] According to the test analysis in Table 1, compared with the pure sulfonated PEEK film in Comparative Example 1, the sulfonated PEEK film in Example 3 has a significantly lower swelling rate, indicating that the film has higher stability in the solution, and the swelling rate increases less after soaking at high temperature of 70℃, indicating that the film has higher high-temperature resistance and durability. In addition, the sulfonated PEEK film in Example 3 has lower vanadium ion concentration and higher proton conductivity, indicating that the film has higher selectivity and is more suitable for use as a proton exchange membrane for hydrogen fuel cells.

[0100] Compared with Comparative Examples 2 and 3, Example 3 also shows higher stability, high-temperature resistance and selectivity, indicating that the silica is sulfonated, and then the PEI is grafted on the silica, the interface morphology of the silica is adjusted, and the dispersibility of the silica is improved, so as to improve the internal structure of the sulfonated PEEK film, thereby improving various application performances.

[0101] Compared with Example 3, Examples 4 and 5 perform better in high-temperature resistance and selectivity, indicating that the mesoporous silica prepared by using polystyrene microspheres as a template can promote sulfonation and be helpful for PEI grafting and coating, thereby playing a role in structural modification of the sulfonated PEEK film.

[0102] The specific embodiment is only an explanation of the present application, and is not a limitation of the present application. Those skilled in the art can make modifications to the specific embodiment without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A sulfonated PEEK thin film for hydrogen fuel cells, characterized in that: It is prepared from raw materials comprising the following parts by weight: 100 parts of sulfonated PEEK; 3-7 parts of PEI-grafted silica filler; The PEI-grafted silica filler is formed by reacting PEI and sulfonated silica under the crosslinking action of aliphatic diamine. The mass ratio of PEI, sulfonated silica and aliphatic diamine is 1:(1.1~1.5):(0.3~0.5). PEI is polyetherimide.

2. The sulfonated PEEK thin film for hydrogen fuel cells according to claim 1, characterized in that: The sulfonated silica is obtained by reacting silica with a mercaptosilane coupling agent to obtain mercaptosilane, and then oxidizing the mercaptosilane to obtain sulfonated silica. The mass ratio of silica to mercaptosilane coupling agent is 1:(0.05~0.09).

3. The sulfonated PEEK thin film for hydrogen fuel cells according to claim 2, characterized in that: The mercaptosilane coupling agent includes one or both of 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

4. The sulfonated PEEK thin film for hydrogen fuel cells according to claim 2, characterized in that: The silica is produced by aging and calcining orthosilicates with polystyrene microspheres as templates through a sol-gel process.

5. The sulfonated PEEK thin film for hydrogen fuel cells according to claim 1, characterized in that: The aliphatic diamine includes one or both of ethylenediamine and butanediamine.

6. A method for preparing a sulfonated PEEK thin film for a hydrogen fuel cell according to any one of claims 1-5, characterized in that: Includes the following steps: PEI was dissolved in the first solvent. After the solution was evenly dissolved, sulfonated silica was added and stirred to disperse it evenly. Then, aliphatic diamine was added, and the mixture was stirred continuously and then filtered to obtain PEI-grafted silica filler. Sulfonated PEEK is dissolved in a second solvent. After the solution is uniformly dissolved, PEI-grafted silica filler is added, stirred and dispersed evenly, degassed, coated onto a substrate, and dried to remove the first solvent, thus obtaining a sulfonated PEEK film.

7. The method for preparing a sulfonated PEEK thin film for a hydrogen fuel cell according to claim 6, characterized in that: The method for preparing the sulfonated silicon dioxide includes the following steps: Silica was dispersed in a third solvent, a mercaptosilane coupling agent was added, and the mixture was heated to react. After the reaction was completed, the mixture was filtered to collect the solid. The solid was then added to an oxidizing agent solution to react. After the reaction was completed, the mixture was filtered to obtain sulfonated silica.

8. The method for preparing a sulfonated PEEK thin film for a hydrogen fuel cell according to claim 7, characterized in that: The method for preparing the silicon dioxide includes the following steps: Orthosilicate is added to a mixture of alcohol and water containing a catalyst, stirred and hydrolyzed, heated and evaporated to obtain a gel, dried and calcined to obtain silicon dioxide.

9. The method for preparing a sulfonated PEEK thin film for a hydrogen fuel cell according to claim 7, characterized in that: The method for preparing the silicon dioxide includes the following steps: Polystyrene microspheres were immersed in a mixture of alcohol and water, a catalyst was added, and then orthosilicate was added. The mixture was stirred and hydrolyzed, heated and evaporated to obtain a solid, which was then dried and calcined to obtain silicon dioxide.

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