Modified glass fiber cloth reinforced composite proton exchange membrane and its preparation method

Abstract

This invention belongs to the field of hydrogen energy technology and discloses a method for preparing a modified glass fiber cloth reinforced composite proton exchange membrane. The preparation method includes the following steps: coating a glass fiber cloth surface with a silica layer; sulfonating the silica-coated glass fiber cloth; preparing a mixed solution of ion exchange resin and sulfonated silica; impregnating or double-coating the sulfonated glass fiber cloth with the mixed solution; and drying to obtain the modified glass fiber cloth reinforced composite proton exchange membrane. The preparation method of this invention is relatively simple, and the prepared modified glass fiber cloth reinforced composite proton exchange membrane exhibits good proton conductivity and stability, high mechanical strength, and low cost.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy technology, specifically relating to proton exchange membranes and their preparation methods. Background Technology

[0002] The non-renewable nature of fossil fuels and the environmental pollution caused by their long-term use have driven the global development and use of hydrogen energy technologies. Hydrogen production, storage, and conversion of hydrogen into electricity are among the future energy solutions. Proton exchange membranes are core components in water electrolysis for hydrogen production and proton exchange membrane fuel cells, playing a role in conducting hydrogen ions, isolating fuel and oxidant, and blocking electrons.

[0003] An ideal proton exchange membrane (PEM) possesses characteristics such as high proton conductivity, good chemical and thermal stability, high mechanical strength, low fuel permeability, and low cost. Currently, the most commercially available PEM is the perfluorosulfonic acid (PFSA) PEM, represented by Nafion. However, high-temperature dehydration leads to decreased proton conductivity, reduced mechanical properties, increased fuel permeability, and high cost, prompting researchers to investigate composite PEMs and fluorine-free PEMs.

[0004] The structure of composite PEMs mainly combines a perfluorinated non-ionized microporous medium with a perfluorinated ion exchange resin, such as the composite PEM developed by Gore combining a porous polytetrafluoroethylene substrate with Nafion resin. By casting Nafion resin onto a porous polytetrafluoroethylene substrate, the properties of the original membrane are improved, mechanical strength and dimensional stability are enhanced, and membrane costs are reduced. The ion exchange resin filling the pores transports charge carriers and acts as a separator between electrodes. However, the proton conductivity of pore-filled membrane substrates is low, and composite PEMs can only rely on the ion exchange resin in the pores for proton conduction. This requires good control of the substrate's porosity and pore size, uniform and complete filling of the pores with the ion exchange resin, and good interfacial compatibility between the substrate and the resin. This places high demands on the proton exchange membrane fabrication process.

[0005] Fluorine-free PEMs are mainly sulfonated polyaromatic proton exchange membranes, which have advantages such as high mechanical strength, strong physicochemical stability, low price, and better modification potential. However, since sulfonated aromatic polymers do not have the unique hydrophilic-hydrophobic microphase separation structure of Nafion membranes, the proton conductivity of sulfonated polyaromatic proton exchange membranes often depends on a high ion exchange capacity (IEC). However, excessively high ion exchange capacity (IEC) can easily lead to excessive water absorption and swelling of the membrane, or even complete loss of mechanical strength. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to provide a method for preparing a modified glass fiber cloth reinforced composite proton exchange membrane, which improves the proton conductivity, stability and mechanical strength of the proton exchange membrane, and reduces the cost of the membrane.

[0007] To achieve the above objectives, the present invention provides the following specific technical solutions.

[0008] A method for preparing a modified glass fiber cloth reinforced composite proton exchange membrane includes the following steps:

[0009] Step S1: Coat the surface of the glass fiber cloth with a silicon dioxide layer;

[0010] Step S2: sulfonated glass fiber cloth with a silica layer coated on the surface;

[0011] Step S3: Prepare a mixed solution of ion exchange resin and sulfonated silica;

[0012] Step S4: Impregnate or double-coat the glass fiber cloth treated with sulfonation in step S2 with the mixed solution, and dry to obtain a modified glass fiber cloth reinforced composite proton exchange membrane.

[0013] Furthermore, in some preferred embodiments of the present invention, the glass fiber cloth is one of electronic glass fiber cloth, alkali-free glass fiber cloth, and high silica glass fiber cloth.

[0014] Further preferably, the thickness of the glass fiber cloth is 3~30μm and the pore size is 40~140μm.

[0015] Furthermore, in some preferred embodiments of the present invention, step S1 is specifically implemented as follows: tetraethyl orthosilicate is added to water and stirred to form a gel; glass fiber cloth is soaked in the gel for a period of time, and then taken out and dried.

[0016] Further, tetraethyl orthosilicate was added to water and stirred under ice-water bath conditions.

[0017] Further, the soaking time of the glass fiber cloth in the gel is preferred to be 1~5 hours.

[0018] The thickness of the silicon dioxide layer is further preferred to be 20 nm to 1 μm.

[0019] Furthermore, in some preferred embodiments of the present invention, step S2 is specifically implemented as follows: the glass fiber cloth with a silica layer on its surface is soaked in concentrated sulfuric acid, and then removed, cleaned, and dried.

[0020] Further preferably, the concentration of the concentrated sulfuric acid is 12.9~18.4 mol / L.

[0021] Further preferably, the time for soaking the glass fiber cloth with a silica layer on its surface in concentrated sulfuric acid is 4 to 48 hours.

[0022] Further preferably, the temperature at which the glass fiber cloth with a silica layer on its surface is soaked in concentrated sulfuric acid is 20~40℃.

[0023] Furthermore, in some preferred embodiments of the present invention, the ion exchange resin is one of perfluorosulfonic acid ion exchange resin and non-fluorinated sulfonated polyaromatic resin.

[0024] Further preferred perfluorosulfonic acid ion exchange resins are at least one of the following: Nafion series membranes manufactured by DuPont, USA; perfluorosulfonic acid ion exchange resins manufactured by Shandong Dongyue Group, China; and perfluorosulfonic acid ion exchange resins manufactured by Suzhou Kerun New Materials Co., Ltd., China.

[0025] Further, when the ion exchange resin is a fluorine-free sulfonated polyaromatic resin, a coupling agent is added in step S3. Preferably, the fluorine-free sulfonated polyaromatic resin is at least one of sulfonated polyether ether ketone, sulfonated polyarylene ether sulfone, sulfonated polyphenylene ether, and sulfonated polyimide. Preferably, the coupling agent is a silane coupling agent or a titanate coupling agent.

[0026] Further preferably, the amount of sulfonated silica added is 0.1~15wt% of the ion exchange resin.

[0027] Furthermore, in some preferred embodiments of the present invention, the double-sided coating method is selected from flatbed coating and roll-to-roll coating.

[0028] Further preferred flatbed coating methods include blade coating, four-sided film forming machine coating, extrusion coating, and wire rod coating.

[0029] Based on the same inventive concept, the present invention provides a modified glass fiber cloth reinforced composite proton exchange membrane, which is a sandwich structure formed by sulfonic acid resin, modified glass fiber cloth and sulfonic acid resin; wherein, the surface of the modified glass fiber cloth is coated with silicon dioxide and then subjected to sulfonation treatment.

[0030] Furthermore, the modified glass fiber cloth reinforced composite proton exchange membrane is prepared by the above preparation method.

[0031] This invention modifies the surface of a glass fiber cloth with uniform porosity by attaching a layer of sulfonated silica to the surface of the glass fiber cloth, and then encapsulating it with an ion exchange resin to prepare a modified glass fiber cloth reinforced composite proton exchange membrane. The overall preparation process is relatively simple, and the prepared modified glass fiber cloth reinforced composite proton exchange membrane has good proton conductivity and stability, high mechanical strength, and low cost. Attached Figure Description

[0032] Figure 1The polarization curves of water electrolysis at 30°C are shown for the membranes prepared in Example 1, Comparative Example 1, and Comparative Example 2, as well as the original Nafion membrane and Nafion 212 membrane.

[0033] Figure 2 The polarization curves of water electrolysis at 80°C are shown for the membranes prepared in Example 1, Comparative Example 1, and Comparative Example 2, as well as the original Nafion membrane and Nafion 212 membrane.

[0034] Figure 3 The polarization curves of the membranes prepared in Example 2, Comparative Example 3, and Comparative Example 4, as well as the SPEEK membrane, are shown at 30°C during water electrolysis.

[0035] Figure 4 The polarization curves of the membranes prepared in Example 2, Comparative Example 3, and Comparative Example 4, as well as the SPEEK membrane, are shown in the electrolysis water polarization curves at 80°C. Detailed Implementation

[0036] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0037] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0039] This invention provides a modified glass fiber cloth reinforced composite proton exchange membrane and its preparation method.

[0040] The method for preparing the modified glass fiber cloth reinforced composite proton exchange membrane provided by the present invention includes the following steps:

[0041] Step S1: Coat the surface of the glass fiber cloth with a silicon dioxide layer;

[0042] Step S2: sulfonated glass fiber cloth with a silica layer coated on the surface;

[0043] Step S3: Prepare a mixed solution of ion exchange resin and sulfonated silica;

[0044] Step S4: Impregnate or double-coat the glass fiber cloth treated with sulfonation in step S2 with the mixed solution, and dry to obtain a modified glass fiber cloth reinforced composite proton exchange membrane.

[0045] In a specific embodiment, the glass fiber cloth is one of electronic glass fiber cloth, alkali-free glass fiber cloth, and high silica glass fiber cloth.

[0046] In a specific embodiment, the thickness of the glass fiber cloth is preferably 3~30μm and the pore size is 40~140μm.

[0047] (1) For step S1, a silica layer is coated on the surface of the glass fiber cloth:

[0048] The following specific implementation methods can be used to achieve this:

[0049] Tetraethyl orthosilicate is added to water and stirred to form a gel; glass fiber cloth is soaked in the gel for a period of time and then removed.

[0050] Tetraethyl orthosilicate is preferably added to water and stirred under ice-water bath conditions.

[0051] The preferred soaking time for the fiberglass cloth in the gel is 1 to 5 hours.

[0052] (2) For step S2, the glass fiber cloth with a silica layer on the sulfonated surface:

[0053] The following specific implementation method can be used: soak the glass fiber cloth with a silica layer on its surface in concentrated sulfuric acid, and then take it out, clean it, and dry it.

[0054] Preferably, the concentration of the concentrated sulfuric acid is 12.9~18.4 mol / L; more preferably, it is 18.4 mol / L.

[0055] Preferably, the time for soaking the glass fiber cloth with a silica layer on its surface in concentrated sulfuric acid is 4 to 48 hours.

[0056] Preferably, the temperature at which the glass fiber cloth with a silica layer on its surface is soaked in concentrated sulfuric acid is 20~40℃.

[0057] After the glass fiber cloth is coated with a silica layer, it undergoes further sulfonation treatment. The resulting glass fiber cloth has sulfonic acid groups on its surface, which strongly interact with the sulfonic acid groups of the ion exchange resin, ensuring good interfacial compatibility. Based on this, even after repeated swelling and drying, the glass fiber cloth will not detach internally due to inconsistencies in swelling degree and water absorption rate with the ion exchange resin.

[0058] In addition, fiberglass cloth has good acid resistance and mechanical stability, and after sulfonation modification, it has excellent proton conductivity.

[0059] (3) For step S3, prepare a mixed solution of ion exchange resin and sulfonated silica.

[0060] The following specific implementation method can be used: Ion exchange resin and sulfonated silica are added to a solvent, stirred at room temperature for 6 hours to prepare an ion exchange resin mixed solution, and then subjected to degassing treatment. The solvent is preferably N,N-dimethylacetamide.

[0061] Preferably, the amount of sulfonated silica added is 0.1~15wt% of the ion exchange resin. The addition of sulfonated silica and the amount added can prevent the aggregation of inorganic nanoparticles, thereby reducing the proton conductivity.

[0062] Preferably, the mass concentration of ion exchange resin in the mixed solution is 5% to 22% to ensure uniform thickness of the coating or cast film.

[0063] (4) For step S4, impregnate or double-coat the glass fiber cloth treated with sulfonation in step S2 with the mixed solution, and then dry:

[0064] In a specific embodiment, the ion exchange resin is one of perfluorosulfonic acid ion exchange resin and non-fluorinated sulfonated polyaromatic resin.

[0065] In a specific embodiment, when the ion exchange resin is a fluorine-free sulfonated polyaromatic resin, a coupling agent is added in step S3. More preferably, the fluorine-free sulfonated polyaromatic resin is at least one of sulfonated polyether ether ketone, sulfonated polyarylene ether sulfone, sulfonated polyphenylene ether, and sulfonated polyimide. Preferably, the coupling agent is a silane coupling agent or a titanate coupling agent.

[0066] The addition of coupling agents can further enhance the interface between organic polymers and inorganic modified glass fiber cloth, reduce the polymer swelling rate, and prevent the glass fiber cloth from detaching from the polymer during swelling.

[0067] In a specific embodiment, the perfluorosulfonic acid ion exchange resin is at least one of the following: Nafion series membranes manufactured by DuPont, USA; perfluorosulfonic acid ion exchange resins manufactured by Shandong Dongyue Group, China; and perfluorosulfonic acid ion exchange resins manufactured by Suzhou Kerun New Materials Co., Ltd., China.

[0068] In a specific embodiment, the double-sided coating method is selected from flatbed coating and roll-to-roll coating.

[0069] In a specific embodiment, the flat plate coating method is one of blade coating, four-sided film forming machine coating, extrusion coating, and wire bar coating.

[0070] The above preparation method can be used to prepare a proton exchange membrane with a sandwich structure formed by sulfonic acid resin, modified glass fiber cloth, and sulfonic acid resin. The modified glass fiber cloth is coated with a silica layer and then further sulfonated.

[0071] The following specific examples will provide further explanation.

[0072] In a specific embodiment, the performance of the prepared membrane was tested using the following method.

[0073] The water absorption test procedure is as follows:

[0074] The sample was dried in an oven at 80℃±2℃ for 24 hours, then transferred to a desiccator to cool to room temperature. The initial mass of the sample was then weighed using an analytical balance. .

[0075] The water absorption rate test methods at 30℃ and 80℃ are as follows: a) Water absorption rate test at 30℃: Place the sample in a constant temperature water bath at 30℃±2℃ and keep it for at least 2 hours; remove the sample from the constant temperature water bath, blot its surface dry with filter paper, and measure its mass within 30 seconds. b) Place the sample in distilled water at 80℃±2℃ and soak for 1 hour. Then, quickly transfer the sample to room temperature distilled water to cool for 15 minutes±1 minute. Remove the sample from the constant temperature water bath, blot its surface dry with filter paper, and measure its mass within 30 seconds.

[0076] The formula for calculating water absorption rate is:

[0077]

[0078] In the formula, Water absorption rate; The mass of the sample after immersion in a constant temperature water bath is expressed in grams (g). The initial mass of the sample is expressed in grams (g).

[0079] Take 3 samples as a group and calculate the average value as the test result.

[0080] The ion exchange capacity (IEC) test procedure is as follows:

[0081] Ion exchange capacity refers to the amount of ions that a unit volume or mass of ion exchange material can exchange. Ion exchange capacity is generally proportional to the number of active groups per unit volume or mass, reflecting the acid concentration within the proton exchange membrane. The steps for measuring ion exchange capacity using acid-base titration are as follows:

[0082] A 0.1 g membrane sample was taken and immersed in a 1 mol / L hydrochloric acid solution for 72 h. After removal, it was rinsed several times with deionized water until neutral, and then the membrane sample was cut into small pieces. It was then dried in a vacuum oven at 80℃ for 3 h and quickly removed and weighed, which was recorded as M. dry Place the membrane sample in an Erlenmeyer flask containing 15% sodium chloride solution and shake on a shaker for 72 h (to remove H+). +(Completely displaced); using phenolphthalein as an indicator, titrate with 0.2 mol / L sodium hydroxide solution until the phenolphthalein solution turns red and does not fade within half a minute, then record the volume of sodium hydroxide consumed, denoted as V. NaOH The IEC calculation formula is:

[0083]

[0084] In the formula, IEC represents the ion exchange capacity, with units of mmol / g; C NaOH V represents the concentration of the NaOH solution, in mol / L. NaOH The volume of NaOH consumed in the titration is in mL; M dry The dry weight of the sample is measured in grams (g).

[0085] The steps for proton conductivity testing are as follows:

[0086] Preparation before testing: All samples were immersed in a 5% hydrogen peroxide solution at 80℃ for at least 1 hour, rinsed with deionized water, activated in a 1M sulfuric acid solution at 80℃ for at least 1 hour, rinsed with deionized water to remove residual sulfuric acid, and then immersed in deionized water at 80℃ for at least 1 hour.

[0087] The proton conductivity of the polymer membrane was evaluated using an electrochemical workstation. The four-electrode AC impedance method was performed at 100% relative humidity, with a test frequency of 1 Hz–1 MHz, an amplitude of 10 mV, and a test temperature of 20–100 °C. Sample sizes were no smaller than 2 cm × 2 cm. The proton conductivity of the membrane material was calculated using the following formula:

[0088]

[0089] Where R is the surface resistance of the membrane (Ω). For the measurement of planar proton conductivity, L is the distance between the two electrodes (cm), and A is the cross-sectional area of ​​the membrane (cm²). 2 For the measurement of cross-sectional proton conductivity, L is the film thickness (cm), and A is the overlap area of ​​the two electrodes (cm²). 2 ).

[0090] The mechanical performance testing steps are as follows:

[0091] The membrane sample to be tested was cut into pieces with dimensions of 3cm × 1cm. The elongation at break and tensile strength of the membrane were tested using a universal tensile testing machine at a tensile rate of 5mm / min. -1 Each group of membrane samples was tested three times and the average value was calculated.

[0092] The electrolysis performance test process is as follows:

[0093] A membrane electrode assembly (MEA) (2×2cm) using iridium oxide as a catalyst was prepared using the catalyst-coated membrane method (CCM). The gas diffusion layer of the MEA consisted of a carbon plate and a titanium felt. A 10cm×10cm fluororubber gasket covered the MEA with a stainless steel flow field plate. Heating elements and thermocouples were installed on the stainless steel flow field plate for temperature control. Copper plates were stacked at both ends of the stainless steel flow field plate as anode and cathode electrodes. The power supply connected to the electrodes was a commercial battery testing device (TDC1000, Shenzhen Topway Technology Co., Ltd.). Before testing, the electrochemical fixture was set at 0.45 A / cm. 2 Activation was performed at 80℃ for 40–90 min. The electrolyte flow rate was controlled at 50 mL / min during the test. The polarization curves of the MEA were measured at 30℃, 80℃, and a constant voltage range of 1.42V–2V.

[0094] Example 1

[0095] 60g of tetraethyl orthosilicate was added dropwise to 20ml of deionized water, and the mixture was magnetically stirred in an ice-water bath for 3 hours to form a miscible gel. A 5×5cm piece of glass fiber cloth was immersed in the gel for 2 hours, then removed and dried at 100℃ for 24 hours. The dried glass fiber cloth was then immersed in concentrated sulfuric acid with a concentration of 18.4mol / L for 36 hours, followed by washing with a large amount of deionized water and drying to obtain the modified glass fiber cloth.

[0096] Nafion resin and 2wt% sulfonated silica of Nafion resin were added to N,N-dimethylacetamide, stirred at room temperature for 6 hours, and ultrasonically mixed for 1 hour to prepare a mixed solution with a Nafion resin concentration of 7wt%.

[0097] The modified glass fiber cloth was impregnated and cast into a petri dish using a mixed solution, and then vacuum degassed for 1 hour. After drying at 60°C for 6 hours and at 120°C for 4 hours, a sandwich structure composite membrane of perfluorosulfonic acid resin-modified glass fiber cloth-perfluorosulfonic acid resin was obtained.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 1 is that the glass fiber cloth is not modified.

[0100] The specific steps are as follows:

[0101] Nafion resin and 2wt% sulfonated silica of Nafion resin were added to N,N-dimethylacetamide, stirred at room temperature for 6 hours, and ultrasonically mixed for 1 hour to prepare a mixed solution with a Nafion resin concentration of 7wt%.

[0102] Glass fiber cloth was impregnated and cast into a petri dish using a mixed solution, and then vacuum degassed for 1 hour. The mixture was then dried at 60°C for 6 hours and at 120°C for 4 hours to obtain a sandwich-structured composite membrane of perfluorosulfonic acid resin, glass fiber cloth, and perfluorosulfonic acid resin.

[0103] Comparative Example 2

[0104] The difference between this comparative example and Example 1 is that no sulfonated silica was added to the Nafion resin substrate.

[0105] The specific steps are as follows:

[0106] 60g of tetraethyl orthosilicate was added dropwise to 20ml of deionized water, and the mixture was magnetically stirred in an ice-water bath for 3 hours to form a miscible gel. A 5×5cm piece of glass fiber cloth was immersed in the gel for 2 hours, then removed and dried at 100℃ for 24 hours. The dried glass fiber cloth was then immersed in concentrated sulfuric acid with a concentration of 18.4mol / L for 36 hours, followed by washing with a large amount of deionized water and drying to obtain the modified glass fiber cloth.

[0107] Modified glass fiber cloth was impregnated and cast into a petri dish with Nafion resin, vacuum degassed for 1 hour, then dried at 60°C for 6 hours and at 120°C for 4 hours to obtain a sandwich structure composite membrane of perfluorosulfonic acid resin-modified glass fiber cloth-perfluorosulfonic acid resin.

[0108] The composite membranes obtained in Example 1, Comparative Example 1, and Comparative Example 2, as well as the dried Nafion pre-membrane (from DuPont) and Nafion 212 membrane (from DuPont) cast with 20 wt% Nafion dispersion, were subjected to water absorption, ion exchange capacity (ICE), proton conductivity, and mechanical property tests. The test results are shown in Table 1.

[0109] Table 1 Test Results

[0110]

[0111] Figure 1 and Figure 2 The figures show the electrolysis polarization curves of the membranes prepared in Example 1, Comparative Example 1, and Comparative Example 2, as well as the original Nafion membrane and Nafion 212 membrane, at 30°C and 80°C. It can be seen from the figures that the proton exchange membrane obtained in Example 1 has a higher water electrolysis efficiency than other membranes under the same conditions.

[0112] Example 2

[0113] First, polyether ether ketone (PEEK) is stirred at room temperature to dissolve it in concentrated sulfuric acid for 24 hours. Then, the temperature is raised to 50°C and the reaction is continued for 30 minutes to obtain sulfonated polyether ether ketone with a sulfonation degree of 55%.

[0114] Add 60g of tetraethyl orthosilicate dropwise to 20ml of deionized water and stir magnetically in an ice-water bath for 3 hours to form a miscible gel. Immerse a 5×5cm piece of glass fiber cloth in the gel for 2-5 hours, then remove and dry at 100℃ for 24 hours. Immerse the dried glass fiber cloth in 18.4M concentrated sulfuric acid for 36 hours, then wash with plenty of deionized water and dry to obtain the modified glass fiber cloth.

[0115] Sulfonated polyether ether ketone (SPEEK), titanate coupling agent (HY311W), and 2 wt% sulfonated silica were added to the solvent N,N-methylformamide and stirred at room temperature for 6 hours to prepare a mixed solution with a sulfonated polyether ether ketone concentration (solid content) of 3 wt%, and then degassed.

[0116] The modified glass fiber cloth was impregnated and cast into a petri dish using a mixed solution, and then vacuum degassed for 1 hour. After drying at 60°C for 6-8 hours and at 120°C for 4 hours, a sandwich structure composite membrane of SPEEK-modified glass fiber cloth-SPEEK was obtained.

[0117] Comparative Example 3

[0118] The difference between this comparative example and Example 2 is that the glass fiber cloth is not modified.

[0119] The specific steps are as follows:

[0120] First, PEEK is stirred at room temperature to dissolve it in concentrated sulfuric acid for 24 hours; then the temperature is raised to 50°C and the reaction is continued for 30 minutes to obtain sulfonated polyether ether ketone with a sulfonation degree of 55%.

[0121] Sulfonated polyether ether ketone (SPEEK), titanate coupling agent (HY311W), and 2 wt% sulfonated silica of sulfonated polyether ether ketone were added to solvent N,N-dimethylformamide and stirred at room temperature for 6 hours to prepare a mixed solution with a polyether ether ketone concentration (solid content) of 3 wt%, and then degassed.

[0122] The glass fiber cloth was impregnated and cast into a petri dish using a mixed solution. The mixture was then degassed under vacuum for 1 hour, dried at 60°C for 6-8 hours, and then dried at 120°C for 4 hours to obtain a sandwich-structured composite membrane of SPEEK-glass fiber cloth-SPEEK.

[0123] Comparative Example 4

[0124] The difference between this comparative example and Example 2 is that no sulfonated silica was added to the SPEEK substrate.

[0125] The specific steps are as follows:

[0126] First, PEEK is stirred at room temperature to dissolve it in concentrated sulfuric acid for 24 hours; then the temperature is raised to 50°C and the reaction is continued for 30 minutes to obtain sulfonated polyether ether ketone with a sulfonation degree of 55%.

[0127] Add 60g of tetraethyl orthosilicate dropwise to 20ml of deionized water and stir magnetically in an ice-water bath for 3 hours to form a miscible gel. Immerse a 5×5cm piece of glass fiber cloth in the gel for 2-5 hours, then remove and dry at 100℃ for 24 hours. Immerse the dried glass fiber cloth in 18.4M concentrated sulfuric acid for 36 hours, then wash with plenty of deionized water and dry to obtain the modified glass fiber cloth.

[0128] Sulfonated polyether ether ketone (SPEEK) and titanate coupling agent (HY311W) were added to solvent N,N-dimethylformamide and stirred at room temperature for 6 hours to prepare a mixed solution with a sulfonated polyether ether ketone concentration (solid content) of 3wt%, and then degassed.

[0129] The modified glass fiber cloth was impregnated and cast into a petri dish using a mixed solution, and then vacuum degassed for 1 hour. After drying at 60°C for 6-8 hours and at 120°C for 4 hours, a sandwich structure composite membrane of SPEEK-modified glass fiber cloth-SPEEK was obtained.

[0130] The composite membranes obtained in Example 2, Comparative Example 3, and Comparative Example 4, as well as the pure SPEEK membrane, were subjected to water absorption, ion exchange capacity (ICE), proton conductivity, and mechanical property tests. The results are shown in Table 2.

[0131] Table 2 Test Results

[0132]

[0133] Figure 3 and Figure 4 The figures show the electrolysis polarization curves of the proton exchange membranes obtained in Example 2, Comparative Example 3, Comparative Example 4, and SPEEK membranes at 30°C and 60°C, respectively. It can be seen from the figures that the proton exchange membrane obtained in Example 2 has a higher electrolysis efficiency than other membranes under the same conditions.

[0134] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a modified glass fiber cloth reinforced composite proton exchange membrane, characterized in that, Includes the following steps: Step S1: Coat the surface of the glass fiber cloth with a silicon dioxide layer; Step S2: sulfonated glass fiber cloth with a silica layer coated on the surface; Step S3: Prepare a mixed solution of ion exchange resin and sulfonated silica; Step S4: Impregnate or double-coat the glass fiber cloth treated with sulfonation in step S2 with the mixed solution, and dry to obtain a modified glass fiber cloth reinforced composite proton exchange membrane. The ion exchange resin is one of perfluorosulfonic acid ion exchange resin and non-fluorinated sulfonated polyaromatic resin.

2. The preparation method according to claim 1, characterized in that, The specific implementation method of step S1 is as follows: add tetraethyl orthosilicate to water, stir to form a gel; soak the glass fiber cloth in the gel for a period of time, and then take it out and dry it.

3. The preparation method according to claim 1, characterized in that, The thickness of the silicon dioxide layer is 20 nm to 1 μm.

4. The preparation method according to claim 1, characterized in that, The specific implementation method of step S2 is as follows: soak the glass fiber cloth with a silica layer on its surface in concentrated sulfuric acid, and then take it out, clean it, and dry it.

5. The preparation method according to claim 1, characterized in that, When the ion exchange resin is a fluorine-free sulfonated polyaromatic resin, a coupling agent is added in step S3.

6. The preparation method according to claim 1, characterized in that, The amount of sulfonated silica added is 0.1 to 15 wt% of the ion exchange resin.

7. The preparation method according to claim 1, characterized in that, The double-sided coating method is selected from flatbed coating and roll-to-roll coating.

8. A modified glass fiber cloth reinforced composite proton exchange membrane, characterized in that, The material is prepared by the preparation method according to any one of claims 1 to 7; it is a sandwich structure formed by sulfonic acid resin, modified glass fiber cloth, and sulfonic acid resin; wherein the surface of the modified glass fiber cloth is coated with silica and then subjected to sulfonation treatment.

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