A cross-linked quaternary ammonium base anion exchange membrane, a preparation method and application thereof

Abstract

The application provides a cross-linked quaternary ammonium alkali type anion exchange membrane and belongs to the technical field of fuel cell materials.The cross-linked quaternary ammonium alkali type anion exchange membrane provided by the application has a chemical composition comprising a polymer with a structure shown in formula I.The cross-linked quaternary ammonium alkali type anion exchange membrane provided by the application uses a polycarbazole-triphenyl polymer without an ether bond as a hydrophobic main chain, and introduces a cross-linking agent 1-methyl-4-piperidone to improve the mechanical properties of AEMs and improve the dimensional stability.In order to weaken the negative influence of cross-linking on the ion conduction capacity of AEMs, the application introduces a double-cation cross-linking agent 4,4'-trimethylene bis(1-methylpiperidine) to ensure the ion transmission sites in the membrane, and improve the ion conductivity and mechanical strength of the cross-linked AEMs.The application provides a preparation method of the cross-linked quaternary ammonium alkali type anion exchange membrane, and the method is simple in operation, low in cost and easy to realize industrial mass production.

Description

Technical Field

[0001] This invention relates to the field of fuel cell materials technology, and in particular to a cross-linked quaternary ammonium base anion exchange membrane, its preparation method, and its application. Background Technology

[0002] The use of fossil fuels has significantly improved human living standards, but it has also increased environmental pollution and greenhouse gas emissions. Therefore, shifting the energy mix from fossil fuels to renewable energy sources to meet the growing global energy demand through sustainable development is essential. Polymer electrolyte fuel cells (MEFCs) can directly convert the chemical energy in fuel into electrical energy, avoiding the energy loss associated with mechanical energy during combustion in internal combustion engines. They are not limited by the Carnot cycle and therefore have high energy conversion efficiency, making them considered the best energy conversion device for utilizing hydrogen energy. Furthermore, MEFCs offer advantages such as a wide range of fuel sources and environmentally friendly reaction products.

[0003] Based on the type of ions transported by the electrolyte membrane, polymer electrolyte fuel cells can be divided into proton exchange membrane fuel cells (PEMFCs) and anion exchange membrane fuel cells (AEMFCs). PEMFCs can operate at low temperatures, exhibit strong stability, and demonstrate excellent battery performance, and are currently relatively mature in development. However, PEMFCs rely on precious metal catalysts, resulting in high costs and limiting their widespread global application. By switching from an acidic to an alkaline environment, many non-precious metal catalysts such as Ag, Ni, and Co can be used, thus giving AEMFCs a significant cost advantage. Furthermore, AEMFCs also possess advantages such as higher oxygen reduction reaction kinetics and lower fuel permeability, attracting widespread attention from researchers.

[0004] As a core component of AEMFCs, the development of anion exchange membranes (AEMs) mainly faces the challenge of balancing ion conductivity and mechanical properties. To improve conductivity, AEMs are typically expected to have a high ion exchange capacity (IEC), increasing the density of ionic groups within the membrane to form effective ion transport channels and enhance ion conductivity. However, excessively high IEC can cause the membrane to over-absorb water and swell, leading to a decrease in mechanical properties. Crosslinking is a relatively direct method to address this issue. Currently, the simplest method for preparing crosslinked membranes is direct reaction with diamines such as 1,6-hexanediamine or dibromo crosslinking agents. Compared to the original membrane, conventionally crosslinked AEMs prepared with hydrophobic crosslinking agents have a lower swelling ratio and higher tensile strength, but their network crosslinking structure limits ion conductivity. In summary, designing and controlling the molecular structure of AEMs to balance the relationship between conductivity and mechanical properties, and developing AEMs with high conductivity and good mechanical stability, is of great significance to the development of AEMFCs. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a cross-linked quaternized alkali anion exchange membrane, its preparation method and application. The cross-linked quaternized alkali anion exchange membrane provided by this invention has high conductivity and good mechanical stability.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a cross-linked quaternized alkaline anion exchange membrane, the chemical composition of which includes a polymer having the structure shown in Formula I:

[0008]

[0009] In Equation I, x and 100-x represent the molar ratio of different repeating units in the structure shown in Equation I; x = 10 to 20.

[0010] This invention provides a method for preparing the above-mentioned cross-linked quaternized alkaline anion exchange membrane, comprising the following steps:

[0011] 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone, an acid catalyst and a first organic solvent were mixed and polymerized to obtain polycarbazole-terphenyl polymer.

[0012] The polycarbazole-terphenyl polymer, 4,4'-trimethylenebis(1-methylpiperidine), and a second organic solvent are mixed to obtain a casting solution;

[0013] The casting solution is applied to the substrate surface, and a crosslinking reaction is carried out under heating conditions to obtain a crosslinked film;

[0014] The cross-linked membrane was subjected to deprotonation, quaternization, and ion exchange in sequence to obtain a cross-linked quaternized basic anion exchange membrane.

[0015] Preferably, the molar ratio of 9-(6-bromohexyl)-9H-carbazole to p-terphenyl is 10-20:80-90;

[0016] The molar ratio of 1-methyl-4-piperidinone to 9-(6-bromohexyl)-9H-carbazole and the total amount of terphenyl is 1.1 to 1.3:1.

[0017] Preferably, the acid catalyst comprises trifluoroacetic acid and trifluoromethanesulfonic acid; the molar ratio of the trifluoroacetic acid to 9-(6-bromohexyl)-9H-carbazole and the total amount of terphenyl is 0.9 to 1:1;

[0018] The molar ratio of trifluoromethanesulfonic acid to the total amount of 9-(6-bromohexyl)-9H-carbazole and p-terphenyl is 10-12:1.

[0019] Preferably, the polymerization reaction is carried out at a temperature of 0–5°C for 10–12 hours.

[0020] Preferably, the molar ratio of 4,4'-trimethylenebis(1-methylpiperidine) to polycarbazole-terphenyl polymer is 1.2 to 1.5:1.

[0021] Preferably, the crosslinking reaction is carried out at a temperature of 80–85°C for 24–36 hours.

[0022] Preferably, the deprotonation method includes the following steps:

[0023] The cross-linked membrane is immersed in a first alkaline solution for deprotonation.

[0024] Preferably, the quaternization method includes the following steps:

[0025] The deprotonated crosslinked membrane was immersed in a mixture of iodomethane and methanol to undergo quaternization.

[0026] Preferably, the ion exchange method includes the following steps:

[0027] The quaternized cross-linked membrane was immersed in a second alkaline solution for ion exchange.

[0028] This invention provides the application of the above-mentioned cross-linked quaternized alkaline anion exchange membrane in the preparation of anion exchange membrane fuel cells.

[0029] This invention provides a cross-linked quaternary ammonium base anion exchange membrane, the chemical composition of which comprises a polymer having the structure shown in Formula I. The anion exchange membrane uses a hydrophobic backbone of a polycarbazole-terphenyl polymer without ether bonds, and introduces a cross-linking agent, 4,4'-trimethylenebis(1-methylpiperidine), to improve the mechanical properties and dimensional stability of the AEMs. To mitigate the negative impact of cross-linking on the ion conductivity of the AEMs, this invention introduces a bicationic cross-linking agent, 4,4'-trimethylenebis(1-methylpiperidine), to ensure ion transport sites within the membrane, while simultaneously improving the ionic conductivity and mechanical strength of the cross-linked AEMs.

[0030] This invention provides a method for preparing the above-mentioned cross-linked quaternary ammonium base anion exchange membrane. This method is simple to operate, low in cost, and easy to achieve industrial-scale mass production. Attached Figure Description

[0031] Figure 1 The synthetic route for cross-linked quaternized base anion exchange membranes;

[0032] Figure 2 The 1H NMR spectrum of polycarbazole-triphenyl polymer PCTP-10 is shown.

[0033] Figure 3 The diagram shows the conductivity and Ea of the anion exchange membrane.

[0034] Figure 4 The stress-strain curve of the anion exchange membrane;

[0035] Figure 5 This is a diagram showing the water absorption and swelling of anion exchange membranes.

[0036] Figure 6 This is the Fourier transform infrared spectrum of the anion exchange membrane. Detailed Implementation

[0037] This invention provides a cross-linked quaternized alkaline anion exchange membrane, the chemical composition of which includes a polymer having the structure shown in Formula I:

[0038]

[0039] In Formula I, x and 100-x represent the molar ratio of different repeating units in the structure shown in Formula I; x = 10 to 20, preferably 10, 15 or 20.

[0040] This invention provides a method for preparing the above-mentioned cross-linked quaternized alkaline anion exchange membrane, comprising the following steps:

[0041] 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone, an acid catalyst and a first organic solvent were mixed and polymerized to obtain polycarbazole-terphenyl polymer.

[0042] The polycarbazole-terphenyl polymer, 4,4'-trimethylenebis(1-methylpiperidine), and a second organic solvent are mixed to obtain a casting solution;

[0043] The casting solution is applied to the substrate surface, and a crosslinking reaction is carried out under heating conditions to obtain a crosslinked film;

[0044] The cross-linked membrane was subjected to deprotonation, quaternization, and ion exchange in sequence to obtain a cross-linked quaternized basic anion exchange membrane.

[0045] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0046] This invention involves mixing 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone, an acid catalyst, and a first organic solvent to undergo a polymerization reaction, yielding a polycarbazole-terphenyl polymer (abbreviated as PCTP-X, where x represents the molar percentage of carbazole structural units in the polymer). In this invention, the chemical formula of the 9-(6-bromohexyl)-9H-carbazole (abbreviated as BHC) is shown in formula a:

[0047]

[0048] In this invention, the 9-(6-bromohexyl)-9H-carbazole is preferably sourced from commercially available products or prepared in-house. When preparing 9-(6-bromohexyl)-9H-carbazole in-house, the preparation method preferably includes the following steps:

[0049] Carbazole, 1,6-dibromohexane, KOH, and an organic solvent were mixed and a substitution reaction was carried out to obtain 9-(6-bromohexyl)-9H-carbazole.

[0050] In this invention, the organic solvent is preferably N,N-dimethylformamide. In this invention, the amount of 1,6-dibromohexane is preferably 2 to 3 times the molar amount of carbazole, more preferably 2.5 times; the amount of KOH is the same as the molar amount of carbazole.

[0051] In this invention, the substitution reaction is preferably carried out under a nitrogen atmosphere. The temperature of the substitution reaction is preferably 0°C, and the time is preferably 36–48 h, more preferably 40–45 h.

[0052] In this invention, after the substitution reaction, the resulting substitution reaction solution is preferably post-treated, and the post-treatment preferably includes the following steps:

[0053] The substitution reaction solution was mixed with cold water and extracted with dichloromethane. The crude product obtained from the extraction was separated and purified by column chromatography.

[0054] In this invention, the cold water is preferably cold deionized water. In this invention, the stationary phase used in the column chromatography separation is silica gel, and the eluent is a mixture of petroleum ether and dichloromethane with a gradient volume ratio.

[0055] In this invention, the preferred method for mixing 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone, the acid catalyst, and the first organic solvent is to first mix 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone with the first organic solvent, and then add the acid catalyst dropwise.

[0056] In this invention, the molar ratio of 9-(6-bromohexyl)-9H-carbazole to p-terphenyl is preferably 10-20:80-90, more preferably 15:85; in this invention, the molar ratio of 1-methyl-4-piperidinone to the total amount of 9-(6-bromohexyl)-9H-carbazole and p-terphenyl is preferably 1.1-1.3:1, more preferably 1.2:1.

[0057] In this invention, the acid catalyst comprises trifluoroacetic acid and trifluoromethanesulfonic acid; the molar ratio of trifluoroacetic acid to 9-(6-bromohexyl)-9H-carbazole to the total amount of terphenyl is preferably 0.9 to 1:1; the molar ratio of trifluoromethanesulfonic acid to 9-(6-bromohexyl)-9H-carbazole to the total amount of terphenyl is preferably 10 to 12:1, more preferably 11:1. This invention uses trifluoroacetic acid and trifluoromethanesulfonic acid as superacid catalysts, which can improve the reactivity of electrophilic substances in acidic media to complete the polymerization reaction.

[0058] In this invention, the first organic solvent is preferably dichloromethane. In this invention, the concentration of 9-(6-bromohexyl)-9H-carbazole in the first organic solvent is preferably 0.6 mol / L.

[0059] In this invention, the polymerization reaction is preferably carried out at a temperature of 0 to 5°C and for a time of 10 to 12 hours, more preferably 11 hours.

[0060] In this invention, after the polymerization reaction, the resulting polymerization reaction solution is preferably subjected to post-treatment, which preferably includes the following steps:

[0061] The obtained polymerization reaction solution was mixed with methanol to precipitate a pale yellow solid.

[0062] The resulting pale yellow solid was washed with water and dried to obtain an orange solid polymer, namely polycarbazole-terphenyl polymer.

[0063] In this invention, the methanol is preferably anhydrous methanol. In this invention, the water used for washing is preferably deionized water. In this invention, the drying is preferably vacuum drying.

[0064] The present invention mixes the polycarbazole-terphenyl polymer, 4,4'-trimethylenebis(1-methylpiperidine), and a second organic solvent to obtain a casting solution.

[0065] In this invention, the molar ratio of 4,4'-trimethylenebis(1-methylpiperidine) to polycarbazole-terphenyl polymer is preferably 1.2 to 1.5:1.

[0066] In this invention, the second organic solvent is preferably a high-boiling-point organic solvent such as N-methylpyrrolidone or dimethyl sulfoxide. In this invention, the concentration of 4,4'-trimethylenebis(1-methylpiperidine) in the second organic solvent is preferably 0.8–1 wt%.

[0067] In this invention, the mixing method is preferably stirring.

[0068] After obtaining the casting solution, the present invention preferably filters the casting solution using a 400-mesh filter cloth.

[0069] In this invention, the casting solution is applied to the surface of a substrate, and a crosslinking reaction is carried out under heating conditions to obtain a crosslinked film. In this invention, the substrate is preferably a solid planar substrate, and more preferably a glass plate.

[0070] In this invention, the temperature of the crosslinking reaction is preferably 80-85°C, and the time is preferably 24-36 h, more preferably 28-32 h.

[0071] In this invention, after the crosslinking reaction, the resulting crosslinking reaction solution is preferably washed with water to remove excess crosslinking agent. In this invention, the water used for the washing is preferably deionized water.

[0072] After obtaining the cross-linked membrane, the present invention sequentially performs deprotonation, quaternization, and ion exchange on the cross-linked membrane to obtain a cross-linked quaternized basic anion exchange membrane (abbreviated as QPCTP-x, where x represents the molar percentage of carbazole structural units in the polymer). In the present invention, the deprotonation method preferably includes the following steps:

[0073] The cross-linked membrane is immersed in a first alkaline solution for deprotonation.

[0074] In this invention, the first alkaline solution is preferably a NaOH solution, and the concentration of the NaOH solution is preferably 1–1.5 mol / L. In this invention, the immersion temperature of the crosslinked membrane in the first alkaline solution is preferably 60–65°C, and the immersion time is preferably ≥24 h, more preferably 24–48 h.

[0075] In this invention, after deprotonation, the resulting crosslinked membrane is preferably washed with water to remove surface alkaline solution.

[0076] In this invention, the quaternization method preferably includes the following steps:

[0077] The deprotonated crosslinked membrane was immersed in a mixture of iodomethane and methanol to undergo quaternization.

[0078] In this invention, the volume ratio of iodomethane to methanol in the mixture of iodomethane and methanol is preferably 1:20.

[0079] In this invention, the quaternization temperature is preferably room temperature, and the time is preferably 24 to 48 hours, more preferably 28 to 40 hours.

[0080] In this invention, after quaternization, the resulting crosslinked membrane is preferably washed with water to remove excess iodomethane.

[0081] In this invention, the ion exchange method preferably includes the following steps:

[0082] The quaternized cross-linked membrane was immersed in a second alkaline solution for ion exchange.

[0083] In this invention, the second alkaline solution is preferably a NaOH solution, and the concentration of the NaOH solution is preferably 1–1.5 mol / L. In this invention, the ion exchange temperature is preferably room temperature, and the time is preferably 36–48 hours. In this invention, during the ion exchange process, iodide ions are replaced by hydroxide ions.

[0084] In this invention, after the ion exchange, the resulting cross-linked membrane is preferably washed with water.

[0085] In this invention, the synthesis route of the cross-linked quaternary ammonium base anion exchange membrane is as follows: Figure 1 As shown. Figure 1 In the equation, x + y = 100.

[0086] This invention provides the application of the above-mentioned cross-linked quaternized alkaline anion exchange membrane in the preparation of anion exchange membrane fuel cells.

[0087] The following detailed description, in conjunction with embodiments, illustrates the cross-linked quaternized alkaline anion exchange membrane, its preparation method, and its applications provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0088] Example 1

[0089] (1) Carbazole (15 g, 89.71 mmol) was added to a 500 mL three-necked round-bottom flask, and 200 mL of LDM was added under mechanical stirring to dissolve it completely. After cooling to 0 °C in an ice-water bath, KOH (5 g, 89.7 mmol) was added to the flask under nitrogen protection. The mixture was stirred at 0 °C for a few minutes, and 1,6-dibromohexane (28 mL, 179.42 mmol) was slowly added dropwise. The reaction was stirred at room temperature for 48 hours. When the reaction was terminated, the mixture was poured into cold deionized water and extracted with dichloromethane. The crude product was purified by silica gel chromatography using a mixture of petroleum ether / dichloromethane in a gradient volume ratio as the eluent to obtain the target product as a white needle-like powder.

[0090] (2) The prepared monomers 9-(6-bromohexyl)-9H-carbazole (0.3 g, 0.96 mmol), p-terphenyl (2 g, 8.68 mmol), and 1-methyl-4-piperidinone (1.45 mL, 12.5 mmol) were dissolved in 5.5 mL of dichloromethane. The reaction system was cooled to 0 °C, and 1.3 mL of trifluoroacetic acid and 10 mL of trifluoromethanesulfonic acid were slowly added dropwise. After reacting at 0 °C for 12 hours, the product was discharged into anhydrous methanol, and a pale yellow solid product was precipitated. The product was then washed several times with deionized water and dried under vacuum to obtain an orange solid product, namely polycarbazole-terphenyl polymer PCTP-10.

[0091] (3) The above polymer PCTP-10 was dissolved in NMP, and then an excess of 50% (w / w) of crosslinking agent 4,4'-trimethylenebis(1-methylpiperidine) was added to the polymer solution and stirred rapidly to disperse it evenly. The casting solution was filtered once through a 400-mesh filter cloth to remove insoluble impurities, and then cast onto a glass plate. The membrane was crosslinked in situ in a vacuum oven at 80°C and dried to form a film. The obtained crosslinked membrane was washed in deionized water to remove excess crosslinking agent. Subsequently, the membrane was immersed in 1M NaOH solution at 60°C for 24 hours for deprotonation. After removing the surface alkali, it was immersed in a methanol solution of iodomethane at room temperature for 48 hours to complete the quaternization reaction. It was rinsed several times with deionized water to remove excess iodomethane. The obtained membrane was immersed in 1M NaOH at room temperature for 48 hours for ion exchange, and then washed with deionized water to finally obtain the crosslinked quaternized alkaline anion exchange membrane QPCTP-10.

[0092] The 1H NMR spectrum of polycarbazole-terphenyl polymer PCTP-10 is shown below. Figure 2 As shown.

[0093] Example 2

[0094] Compared with Example 1, the difference is that 2g (8.68mmol) of p-terphenyl and 0.72g (2.17mmol) of 9-(6-bromohexyl)-9H-carbazole were added to prepare polymer PCTP-20, and then the cross-linked quaternized alkaline anion exchange membrane QPCTP-20 was obtained by similar treatment as in Example 1.

[0095] Comparative Example 1

[0096] The method for preparing QPCTP-0 is as follows:

[0097] 2 g (8.68 mmol) of terphenyl and 1-methyl-4-piperidinone (1.3 mL, 11.3 mmol) were dissolved in 3.5 mL of dichloromethane. The reaction system was cooled to 0 °C, and 0.8 mL of trifluoroacetic acid and 7.0 mL of trifluoromethanesulfonic acid were slowly added dropwise. After reacting at 0 °C for 6 hours, the product was discharged and precipitated in a 1–1.5 mol / L potassium carbonate aqueous solution to obtain a white solid product. The product was then washed several times with deionized water and dried under vacuum to obtain the polymer product. The prepared polymer was dissolved in N-methylpyrrolidone (polymer mass fraction 5 wt%), and twice the excess of iodomethane was added. The reaction was carried out at room temperature in the dark for 48 hours to complete the quaternization reaction. After the reaction was completed, the product was discharged into ethyl acetate, washed three times with deionized water, and dried at 60–65 °C for at least 24 hours to obtain the QPCTP-0 product.

[0098] Performance testing

[0099] (1) The conductivity of QPCTP-10, QPCTP-20, and QPCTP-0 was tested using the four-electrode AC impedance method on membrane strips cut to 1 cm × 4.5 cm. The resistance was measured at frequencies from 0.1 to 100 kHz from room temperature to 80 °C to calculate the ionic conductivity. The conductivity diagram and Ea diagram of the anion exchange membrane are shown below. Figure 3 As shown, by Figure 3 It can be seen that the conductivity of the cross-linked membrane QPCTP-x did not decrease compared to QPCTP-0, indicating that the introduction of a multi-cationic cross-linking agent does not affect conductivity. With increasing cross-linking agent content, the conductivity of QPCTP-20 significantly increased, reaching 117.7 mS / cm at 80℃ for the OH- conductivity. -1 This is attributed to the introduction of multi-cationic crosslinking agents, which increases the number of conductive sites within the membrane, facilitating the aggregation of ionic groups and improving the conductivity of the AEM. The invention uses the Arrhenius equation to calculate the activation energy of ion conduction. Compared to QPCTP-0 and QPCTP-10, the QPCTP-20 membrane exhibits a lower Ea, indicating that ions have a smooth transport path within the membrane.

[0100] (2) Stress-strain tests were performed on the conductivity of QPCTP-10 and QPCTP-20, and the resulting stress-strain curves are shown below. Figure 4 As shown, by Figure 4As can be seen, the tensile strength of the membrane can be maintained at a high level due to the presence of the cross-linked structure. QPCTP-10 achieves a tensile strength of 57 MPa and an elongation at break of 16.6%. With increasing cross-linking agent content, the number of transport sites within the membrane increases. Due to the plasticizing effect of water, the elongation at break of QPCTP-20 increases to 20.2%, but the tensile strength decreases to 54 MPa. Therefore, the introduction of multi-cationic cross-linking agents can ensure that the membrane possesses excellent mechanical properties, overcome the balance between ion conductivity and mechanical properties, and meet the basic application requirements of AEMFC.

[0101] (3) The water absorption and swelling properties of QPCTP-10, QPCTP-20, and QPCTP-0 were tested. The specific method was as follows: the mass and side length of the membrane material in the dry state were recorded. Then, the membrane was immersed in deionized water at a temperature ranging from room temperature to 80℃ for 12 hours. The mass and side length of the membrane material were measured again to calculate the water absorption rate and swelling degree of the membrane. The resulting water absorption and swelling diagram is shown below. Figure 5 As shown, by Figure 5 It can be seen that QPCTP-x AEMs exhibit lower water absorption and swelling degree in the temperature range of 20℃ to 80℃. Due to the addition of the multi-cationic crosslinking agent, more water transport sites are introduced, resulting in higher water absorption (WU) and swelling degree (SR) for the crosslinked membrane compared to QPCTP-0 AEM. The SR of QPCTP-x AEMs remains between 21% and 23% in the temperature range of 20℃ to 80℃, demonstrating low swelling and reducing the impact of humidity changes on the membrane electrode structure during AEMFC operation. With increasing crosslinking degree, the WU and SR of QPCTP-x AEMs decrease. Due to the presence of the crosslinked structure, the WU and SR of the membrane can be controlled at low levels and show little change with increasing temperature, exhibiting good dimensional stability.

[0102] (4) Fourier transform infrared spectroscopy (FTIR) was performed on QPCTP-10 and QPCTP-20. The specific method was as follows: the membrane samples were dried to constant weight, and the scan count was set to 64 for background and sample acquisition. The obtained Fourier transform infrared spectra are as follows: Figure 6 As shown, 2929cm -1 The nearby signal peaks are related to the vibrations of the methylene group, and their peak intensity increases with increasing crosslinking agent content. The peak value is at 1030 cm⁻¹. -1 The corresponding ammonium group CN + The vibration indicates that the cross-linking reaction has proceeded successfully.

[0103] 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 cross-linked quaternary ammonium base anion exchange membrane, the chemical composition of which comprises a polymer having the structure shown in Formula I: Equation I; In Equation I, x and 100-x represent the molar ratio of different repeating units in the structure shown in Equation I; x = 10~20; The preparation method of the cross-linked quaternized alkaline anion exchange membrane includes the following steps: 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone, an acid catalyst and a first organic solvent were mixed and polymerized to obtain polycarbazole-terphenyl polymer. The polycarbazole-terphenyl polymer, 4,4'-trimethylenebis(1-methylpiperidine), and a second organic solvent are mixed to obtain a casting solution; The casting solution is applied to the substrate surface, and a crosslinking reaction is carried out under heating conditions to obtain a crosslinked film; The cross-linked membrane was subjected to deprotonation, quaternization, and ion exchange in sequence to obtain a cross-linked quaternized basic anion exchange membrane.

2. The method for preparing the cross-linked quaternary ammonium base anion exchange membrane according to claim 1, comprising the following steps: 9-(6-bromohexyl)-9H-carbazole, p-terphenyl, 1-methyl-4-piperidinone, an acid catalyst and a first organic solvent were mixed and polymerized to obtain polycarbazole-terphenyl polymer. The polycarbazole-terphenyl polymer, 4,4'-trimethylenebis(1-methylpiperidine), and a second organic solvent are mixed to obtain a casting solution; The casting solution is applied to the substrate surface, and a crosslinking reaction is carried out under heating conditions to obtain a crosslinked film; The cross-linked membrane was subjected to deprotonation, quaternization, and ion exchange in sequence to obtain a cross-linked quaternized basic anion exchange membrane.

3. The preparation method according to claim 2, characterized in that, The molar ratio of 9-(6-bromohexyl)-9H-carbazole to p-terphenyl is 10~20:80~90; The molar ratio of 1-methyl-4-piperidinone to 9-(6-bromohexyl)-9H-carbazole and the total amount of terphenyl is 1.1~1.3:

1.

4. The preparation method according to claim 2 or 3, characterized in that, The acid catalyst comprises trifluoroacetic acid and trifluoromethanesulfonic acid; the molar ratio of trifluoroacetic acid to 9-(6-bromohexyl)-9H-carbazole and the total amount of terphenyl is 0.9~1:1; The molar ratio of trifluoromethanesulfonic acid to the total amount of 9-(6-bromohexyl)-9H-carbazole and p-terphenyl is 10~12:1; The polymerization reaction is carried out at a temperature of 0-5℃ for 10-12 hours.

5. The preparation method according to claim 2, characterized in that, The molar ratio of 4,4'-trimethylenebis(1-methylpiperidine) to polycarbazole-terphenyl polymer is 1.2~1.5:

1.

6. The preparation method according to claim 2, characterized in that, The cross-linking reaction is carried out at a temperature of 80-85°C for 24-36 hours.

7. The preparation method according to claim 2, characterized in that, The deprotonation method includes the following steps: The cross-linked membrane is immersed in a first alkaline solution for deprotonation.

8. The preparation method according to claim 2, characterized in that, The quaternization method includes the following steps: The deprotonated crosslinked membrane was immersed in a mixture of iodomethane and methanol to undergo quaternization.

9. The preparation method according to claim 2, characterized in that, The ion exchange method includes the following steps: The quaternized cross-linked membrane was immersed in a second alkaline solution for ion exchange.

10. The application of the cross-linked quaternized alkaline anion exchange membrane according to claim 1 or the cross-linked quaternized alkaline anion exchange membrane prepared by any one of claims 2 to 9 in the preparation of anion exchange membrane fuel cells.

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