A poly(arylene) ion-conducting membrane containing a dual electron-withdrawing side chain structure and a method of making the same

Abstract

The application is suitable for the field of new energy energy storage flow battery, and provides a polyaryl ion conductive film containing double electron-withdrawing side chain structure and a preparation method thereof.The application is characterized by comprising the following steps: (1) preparing a polyaryl main chain polymer through an ultrastrong acid mediated polycondensation reaction, wherein the polyaryl main chain contains double electron-withdrawing side chain structure; (2) performing a sulfonation reaction on the polyaryl main chain polymer to graft a sulfonic acid group capable of conducting protons on the main chain benzene ring; and (3) preparing a homogeneous and dense ion conductive film from the sulfonated polyaryl polymer through a solution casting method.The polyaryl ion conductive film containing double electron-withdrawing functional side chains prepared by the application can redistribute the electron cloud density of the main chain through the electron-withdrawing effect of the side chain, promote the dissociation of the sulfonic acid group and repel vanadium ions, so that the hydrogen vanadium ion selectivity and cycle stability of the energy storage all-vanadium redox flow battery are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of new energy storage battery technology, and relates to a polyaryl ion conduction membrane containing a double electron-withdrawing side chain structure and its preparation method. Background Technology

[0002] The large-scale application of renewable energy sources such as wind and solar power provides an effective way to solve the energy crisis and environmental pollution caused by fossil fuel emissions. However, renewable energy is intermittent and unstable, requiring efficient energy storage systems to ensure stable power output. Vanadium redox flow batteries (VRFBs) have advantages such as high safety and capacity-power decoupling, making them the preferred choice for large-scale energy storage devices. As one of the core components of VRFBs, the ion-conducting membrane needs to block vanadium ion penetration to reduce self-discharge side reactions and enhance proton conduction to maintain charge balance, significantly impacting key VRFB performance such as energy efficiency, capacity decay rate, and long-term charge-discharge cycle life. Currently, the ion-conducting membrane has H... + / V n+ Selectivity trade-offs and insufficient chemical stability under strong acid and strong oxidizing battery operating conditions limit the practical application of VRFBs and have become the main challenges for ion-conducting membranes.

[0003] The chemical structure design of ion-conducting membranes is crucial for regulating the morphology of ion-selective conduction channels and the chemical stability of the membrane. Commercial Nafion membranes exhibit extremely high chemical stability due to the CF bonds in their polymer backbone; however, the large size of the proton conduction channels constructed from their ion clusters leads to H... + / V n+ Poor selectivity and severe battery capacity degradation. Non-fluorinated ion-conducting membranes, such as sulfonated polyether ether ketone, sulfonated polysulfone, and sulfonated polyimide, have aromatic ring backbones with significant steric hindrance, effectively blocking vanadium ion penetration. However, the bond energies of their heteroatoms (sulfonyl groups (O=S=O), ether bonds (-O-), imide groups (O=CNC=O), etc.) are low, especially the ether bonds in the polymer backbone, which are susceptible to VO2. + Attacks can cause fractures, leading to accelerated membrane material degradation, battery capacity decay, and decreased cycle performance. Polyarylene matrices without heteroatoms exhibit better chemical stability, and current research focuses on designing functional side chains to regulate H... + / V n+Selective conduction channels. For example, J. Mater. Chem. A 12 (2024) 15914-15921 designed a proton exchange membrane with a quinone-convertible sulfate-type ion-conducting side chain structure using an in-situ chemical transformation method; further, J. PowerSources 614 (2024) 235014 proposed a proton exchange membrane with a quinone-convertible phenolic hydroxyl side chain structure, which forms a continuous ion-conducting channel through hydrogen bonding; Chem. Eng. J. 494 (2024) 153231 synthesized a membrane with a weakly bonded pyridine side chain structure using an acid-mediated condensation reaction and used a phosphoric acid pre-swelling strategy to improve selectivity; Adv. Funct. Mater. 34 (2024) 2316506 used the same reaction design to prepare a proton exchange membrane with a microblock structure containing disulfonic acid side chains, which improved hydrophilic-hydrophobic phase separation and enhanced proton conduction; J. Membr. Sci. 697 (2024) 122540 A hydrophobic fluorinated side-chain modified polyarylpiperidine membrane was designed, with the fluorinated structure enhancing stability. Although the aforementioned side-chain structure design improves proton conductivity or stability to some extent, the resulting ion channels are difficult to control to overcome the trade-off between proton and vanadium ion permeation. Functional side-chain designs for polyaryl matrix ion-conducting membranes prepared based on acid-mediated polycondensation reactions cannot simultaneously satisfy high ion selectivity and chemical stability, and also exhibit limited charge-discharge cycle stability (typically less than 2000 cycles), especially at high current densities, due to the interaction with the H+ ion in the proton conduction channels. + / V n+ Energy efficiency with high selectivity still needs improvement. Summary of the Invention

[0004] This invention provides a polyaryl ion-conducting membrane containing double electron-withdrawing functional side chains and its preparation method: First, a polyaryl polymer containing double electron-withdrawing side chains is prepared through a superacid-mediated polycondensation reaction. Then, sulfonic acid groups are grafted onto the main chain benzene ring using concentrated sulfuric acid sulfonation. Finally, a proton-conducting membrane is prepared by solution casting. The double electron-withdrawing groups of the side chains have a strong electron-withdrawing effect, which can redistribute the electron cloud density of the main chain. This not only enhances the proton dissociation ability of the sulfonic acid groups on the main chain benzene ring to promote proton conduction, but also enhances the electrostatic potential of the hydrogen atoms in the main chain benzene ring to repel vanadium ions and increase the oxidation barrier, thereby improving the H2O conductivity of the membrane. + / V n+ Selectivity and oxidation stability. When applied in vanadium redox flow batteries, it exhibits excellent battery energy efficiency, long-term cycle stability, and extremely low discharge capacity decay rate.

[0005] The technical solution of the present invention is as follows: A polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure, wherein the molecular structure of the polyaryl ion-conducting membrane containing the double electron-withdrawing side chain structure is as follows: Where R1 and R2 are both electron-withdrawing groups; n is a positive integer.

[0006] Furthermore, R1 is -F or -CF3; R2 is -COOH, -F, -CF3, -CN, -NO2, -SO3H or -CHO.

[0007] A method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure is disclosed. First, a polyaryl polymer containing a double electron-withdrawing side chain structure is prepared via a superacid-mediated polycondensation reaction. Then, sulfonate groups are grafted onto the benzene rings of the polyaryl polymer backbone via a sulfonation reaction. After washing and drying, a sulfonated polyaryl polymer is obtained. Finally, the sulfonated polyaryl polymer is dissolved in an organic solvent, and the polyaryl ion-conducting membrane is prepared by solution casting. After acidification, it is ready for use. The specific reaction equations are as follows: .

[0008] Furthermore, the superacid-mediated polycondensation reaction refers to dissolving p-terphenyl and ketone-containing aromatic monomers in an organic solvent, then adding a superacid catalyst dropwise, stirring the reaction, precipitating with deionized water, immersing in an alkaline solution for neutralization, removing and repeatedly washing with deionized water until neutral, and drying to obtain a polyaryl polymer. The sulfonation reaction refers to placing the polyaryl polymer in concentrated sulfuric acid, stirring to carry out the sulfonation reaction, precipitating with deionized water, washing until neutral, filtering, centrifuging, and drying to obtain a sulfonated polyaryl polymer with sulfonic acid groups grafted onto the main chain benzene ring. The solution casting method refers to dissolving sulfonated polyaryl polymer in an organic solvent to prepare a casting solution, casting the casting solution onto a substrate, drying to remove the organic solvent, and obtaining a polyaryl ion-conducting membrane with a double electron-withdrawing side chain structure. The acidification refers to immersing the polyaryl ion-conducting membrane in an H2SO4 solution to obtain a polyaryl ion-conducting membrane with H-type sulfonic acid.

[0009] Furthermore, in the superacid-mediated polycondensation reaction: the ketone-containing aromatic monomer refers to an organic monomer containing a ketone structure added during the reaction, and containing two electron-withdrawing groups, R1 and R2, where R1 is -F or -CF3; R2 is -COOH, -F, -CF3, -CN, -NO2, -SO3H, or -CHO; the organic solvent is dichloromethane or chloroform; the molar ratio of terphenyl to the ketone-containing aromatic monomer is 1:1.1~1.4, wherein the concentration of terphenyl in the organic solvent is 0.6~1.2 mol / L. -1The superacid catalyst mentioned refers to a catalyst capable of catalyzing the reaction of ketone-containing aromatic monomers; the superacid catalyst is added dropwise at a temperature of 0-30℃; the mass ratio of the superacid catalyst to p-terphenyl is 8-12; and the stirring reaction time is 6-32 hours.

[0010] Furthermore, the ketone-containing aromatic monomer is 2,2,2-trifluoroacetylbenzoic acid, 2,2,2-trifluoro-1-(4-(trifluoromethyl)phenyl)ethyl ketone, or 2,2,2,4'-tetrafluoroacetophenone.

[0011] Furthermore, the superacid catalyst is trifluoromethanesulfonic acid or trifluoroacetic acid; the concentration of the alkaline solution is 2~6 M; and the alkali in the alkaline solution is potassium carbonate, sodium carbonate, or sodium bicarbonate.

[0012] Furthermore, in the sulfonation reaction: the sulfonation temperature is 40-120℃, and the reaction time is 2-48 h. The drying temperature is 70-90℃, and the drying time is 12-24 h. The ion exchange capacity of the obtained sulfonated polyaryl polymer is 1.38-2.68 mmol g. -1 .

[0013] Furthermore, in the solution casting method described above: the mass concentration of the casting solution is 1~5 wt%, the organic solvent used in the casting solution is dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DMAC), the drying temperature is 70~90℃, and the drying time is 12-24 h.

[0014] Furthermore, in the acidification process: the concentration of the H2SO4 solution is 2-5 M; the soaking time is 12-36 h.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Enhanced ion selectivity. The electron-withdrawing effect of the double electron-withdrawing group can enhance the proton dissociation of the sulfonic acid group by redistributing the electron cloud density of the main chain benzene ring, thereby promoting proton conduction and improving ion selectivity.

[0016] (2) Enhanced chemical stability. The double electron-withdrawing side chain can enhance the electrostatic potential of the hydrogen atom in the main chain benzene ring, repel vanadium ions, and synergistically improve the chemical stability of the membrane with the ether-free main chain, especially in VO2+. + After soaking in the solution for 28 days, the reduction was less than 0.8%.

[0017] (3) Excellent battery performance. The prepared ion conductivity is 2.59 mmol g. -1 The proton conduction membrane at 280 mA cm -2 The energy efficiency is 79.8%, the coulombic efficiency is 99.7%, and the 200 mA cm⁻¹ efficiency is [not specified]. -2The system can be stabilized after 7000 cycles. Attached Figure Description

[0018] Figure 1 These are scanning electron microscope (SEM) images of the surface and cross-section of the ion-conducting membrane of the present invention, where (a) is the cross-section and (b) is the SEM image. It can be seen that the surface and cross-section of the membrane are dense and uniform, with no obvious defects.

[0019] Figure 2 This is a graph showing the trends of conductivity and sheet resistance of the ion-conducting membranes as a function of ion conductivity in Examples 1, 2, 3, and 4. It can be seen that the polyaryl ion-conducting membranes containing double electron-withdrawing functional side chains prepared in this invention exhibit excellent proton conductivity, with SPTPC-2.59 exhibiting a conductivity of 60.88 mS / cm. -1 The surface resistivity is 0.23 Ω cm. 2 .

[0020] Figure 3 This is a graph showing the ion selectivity and vanadium ion permeation performance of the ion-conducting membranes in Examples 1, 2, and 3. It can be seen that SPTPC-2.59 exhibits the highest ion selectivity, with a value of 5.54 × 10⁻⁶. 10 mS s cm -3 It is superior to the commercially available Nafion 212 membrane (ion selectivity of 0.02 × 10⁻⁶). 10 mS s cm -3 ).

[0021] Figure 4 These are the performance graphs of single cells assembled using the ion-conducting membrane of the present invention in Examples 1, 2, and 3. It can be seen that the cells assembled with SPTPC-2.59 achieve performance at current densities of 60-200 mA cm⁻¹. -2 Under these conditions, the energy efficiency is significantly better than that of the commercial Nafion 212 membrane, and it operates stably for 7000 cycles, demonstrating excellent cycle stability. Detailed Implementation

[0022] The experimental scheme of the present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0023] Example 1 9.2 g of p-terphenyl and 10.46 g of 2,2,2-trifluoroacetylbenzoic acid (R1 = -CF3, R2 = -COOH) were dissolved in 50 mL of dichloromethane solution. Then, 84.8 g of trifluoromethanesulfonic acid solution was added, and the mixture was stirred at 0 °C for 24 h. The precipitate was then precipitated with deionized water, neutralized by soaking in 3 M K₂CO₃ solution for 24 h, washed with water until neutral, and dried to obtain a white polyaryl polymer powder. 10 g of the polyaryl polymer powder was placed in 200 mL of concentrated sulfuric acid and stirred in an oil bath at 60 °C for 24 h. The precipitate was washed with water until neutral, filtered, centrifuged, and dried (80 °C, 18 h) to obtain a sulfonated polyaryl polymer powder. The ion exchange capacity (IEC) was determined to be 2.59 mmol g by acid-base titration. -1 It was named SPTPC-2.59.

[0024] 2 g of SPTPC-2.59 powder was dissolved in 100 mL of DMSO solution to prepare a casting solution. 5 mL of the casting solution was poured onto a clean 4×4 cm glass plate and dried in an 80℃ oven for 18 h to remove the solvent. The plate was then acidified with 3 M H2SO4 solution for 24 h to finally obtain a polyaryl ion-conducting membrane with a double electron-withdrawing side chain structure.

[0025] The proton conductivity of the SPTPC-2.59 ion-conducting membrane described above is 60.88 mS / cm. -1 The surface resistivity is 0.23 Ωcm. 2 The vanadium ion permeability is 1.11 × 10⁻⁶. -9 cm 2 s -1 It possesses a high ion selectivity of 5.54 × 10⁻⁶. 10 mS s cm -3 It is superior to the commercially available Nafion 212 membrane (ion selectivity of 0.02 × 10⁻⁶). 10 mS s cm -3 The SPTPC-2.59 membrane was assembled into a single cell at 200 mA cm⁻¹. -2 With an energy efficiency of 83.1% and a stable cycle life of 7000 times, it demonstrates excellent battery performance.

[0026] Example 2 4.6 g of p-terphenyl and 5.23 g of 2,2,2-trifluoroacetylbenzoic acid (R1 = -CF3, R2 = -COOH) were dissolved in 25 mL of dichloromethane solution. Then, 42.4 g of trifluoromethanesulfonic acid solution was added, and the mixture was stirred at 0 °C for 18 h. The precipitate was then precipitated with deionized water, neutralized by soaking in 3 M K₂CO₃ solution for 24 h, washed with water until neutral, and dried to obtain a white polyaryl polymer powder. 5 g of the polyaryl polymer powder was placed in 100 mL of concentrated sulfuric acid and stirred in an oil bath at 60 °C for 9 h. The precipitate was washed with water until neutral, filtered, centrifuged, and dried (80 °C, 18 h) to obtain a sulfonated polyaryl polymer powder. The ion exchange capacity (IEC) was determined to be 2.38 mmol g by acid-base titration. -1 It was named SPTPC-2.38.

[0027] 4 g of SPTPC-2.38 powder was dissolved in 200 mL of DMSO solution to prepare a casting solution. 5 mL of the casting solution was poured onto a clean 4×4 cm glass plate and dried in an 80℃ oven for 18 h to remove the solvent. The plate was then acidified with 3 M H2SO4 solution for 24 h to finally obtain a polyaryl ion-conducting membrane with a double electron-withdrawing side chain structure.

[0028] The proton conductivity of the SPTPC-2.38 ion-conducting membrane described above is 46.71 mS / cm. -1 The surface resistivity is 0.31 Ωcm. 2 The vanadium ion permeability is 0.94 × 10⁻⁶. -9 cm 2 s -1 It possesses a high ion selectivity of 4.95 × 10⁻⁶. 10 mS s cm -3 It is superior to the commercially available Nafion 212 membrane (ion selectivity of 0.02 × 10⁻⁶). 10 mS s cm -3 The SPTPC-2.59 membrane was assembled into a single cell at 200 mA cm⁻¹. -2 The energy efficiency is 79.5%.

[0029] Example 3 13.8 g of p-terphenyl and 15.7 g of 2,2,2-trifluoroacetylbenzoic acid (R1: -CF3, R2: -COOH) were dissolved in 75 mL of dichloromethane solution. Then, 127.2 g of trifluoromethanesulfonic acid solution was added, and the mixture was stirred at 0 °C for 24 h. The precipitate was then precipitated with deionized water, neutralized by soaking in 3 M K₂CO₃ solution for 24 h, washed with water until neutral, and dried to obtain a white polyaryl polymer powder. 5 g of the polyaryl polymer powder was placed in 100 mL of concentrated sulfuric acid and stirred in an oil bath at 60 °C for 6 h. The precipitate was washed with water until neutral, filtered, centrifuged, and dried (80 °C, 18 h) to obtain a sulfonated polyaryl polymer powder. The ion exchange capacity (IEC) was determined to be 1.38 mmol g by acid-base titration. -1 It was named SPTPC-1.38.

[0030] 6 g of SPTPC-1.38 powder was dissolved in 200 mL of DMSO solution to prepare a casting solution. 5 mL of the casting solution was poured onto a clean 4×4 cm glass plate and dried in an 80℃ oven for 18 h to remove the solvent. The plate was then acidified with 3 M H2SO4 solution for 24 h to finally obtain a polyaryl ion-conducting membrane with a double electron-withdrawing side chain structure.

[0031] The proton conductivity of the SPTPC-1.38 ion-conducting membrane described above is 9.8 mS / cm. -1 The surface resistivity is 0.52 Ω cm. 2 The vanadium ion permeability is 0.21 × 10⁻⁶. -9 cm 2 s -1 The ion selectivity is 4.61 × 10⁻⁶. 10 mS s cm -3 It is superior to the commercially available Nafion 212 membrane (ion selectivity of 0.02 × 10⁻⁶). 10 mS s cm -3 The SPTPC-1.38 membrane was assembled into a single cell and tested at 200 mA cm⁻¹. -2 The energy efficiency is 74.69%.

[0032] Example 4 6.9 g of p-terphenyl and 7.8 g of 2,2,2-trifluoro-1-(4-(trifluoromethyl)phenyl)ethyl ketone (R1: -CF3, R2: -CF3) were dissolved in 40 mL of dichloromethane solution. Then, 67.8 g of trifluoromethanesulfonic acid solution was added, and the mixture was stirred at 0 °C for 20 h. The precipitate was then precipitated with deionized water, neutralized by soaking in 3 M K₂CO₃ solution for 24 h, washed with water until neutral, and dried to obtain a white polyaryl polymer powder. 2 g of the polyaryl polymer powder was placed in 40 mL of concentrated sulfuric acid and stirred in an oil bath at 60 °C for 24 h. The precipitate was washed with water until neutral, filtered, centrifuged, and dried (80 °C, 18 h) to obtain a sulfonated polyaryl polymer powder. The ion exchange capacity (IEC) was determined to be 2.68 mmol g by acid-base titration. -1 It was named SPTPF-2.68.

[0033] 3 g of SPTPF-2.68 powder was dissolved in 100 mL of DMSO solution to prepare a casting solution. 5 mL of the casting solution was poured onto a clean 4×4 cm glass plate and dried in an 80℃ oven for 18 h to remove the solvent. The plate was then acidified with 3 M H2SO4 solution for 24 h to finally obtain a polyaryl ion-conducting membrane with a double electron-withdrawing side chain structure.

[0034] The proton conductivity of the aforementioned SPTPF-2.68 ion-conducting membrane is 72.3 mS / cm. -1 The surface resistivity is 0.18 Ωcm. 2 .

Claims

1. A polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure, characterized in that, The molecular structure of the polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure is as follows: Where R1 and R2 are both electron-withdrawing groups; n is a positive integer.

2. The polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 1, characterized in that, R1 is -F or -CF3; R2 is -COOH, -F, -CF3, -CN, -NO2, -SO3H or -CHO.

3. A method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure as described in any one of claims 1-2, characterized in that, First, a polyaryl polymer containing electron-withdrawing side chains was prepared via a superacid-mediated polycondensation reaction. Then, sulfonic acid groups were grafted onto the benzene rings of the polyaryl polymer backbone via sulfonation. After washing and drying, a sulfonated polyaryl polymer was obtained. Finally, the sulfonated polyaryl polymer was dissolved in an organic solvent, and a polyaryl ion-conducting membrane was prepared by solution casting. After acidification, it was ready for use. The specific reaction equations are as follows: 。 4. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 3, characterized in that, The superacid-mediated polycondensation reaction refers to dissolving p-terphenyl and ketone-containing aromatic monomers in an organic solvent, then adding a superacid catalyst, stirring the reaction, precipitating with deionized water, immersing in an alkaline solution for neutralization, removing and repeatedly washing with deionized water until neutral, and drying to obtain a polyaryl polymer. The sulfonation reaction refers to placing the polyaryl polymer in concentrated sulfuric acid, stirring to carry out the sulfonation reaction, precipitating with deionized water, washing until neutral, filtering, centrifuging, and drying to obtain a sulfonated polyaryl polymer with sulfonic acid groups grafted onto the main chain benzene ring. The solution casting method refers to dissolving sulfonated polyaryl polymer in an organic solvent to prepare a casting solution, casting the casting solution onto a substrate, drying to remove the organic solvent, and obtaining a polyaryl ion-conducting membrane with a double electron-withdrawing side chain structure. The acidification refers to immersing the polyaryl ion-conducting membrane in an H2SO4 solution to obtain a polyaryl ion-conducting membrane with H-type sulfonic acid.

5. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 4, characterized in that, In the superacid-mediated polycondensation reaction: the ketone-containing aromatic monomer refers to an organic monomer containing a ketone structure added during the reaction, and containing two electron-withdrawing groups, R1 and R2, where R1 is -F or -CF3; R2 is -COOH, -F, -CF3, -CN, -NO2, -SO3H, or -CHO; the organic solvent is dichloromethane or chloroform; the molar ratio of p-terphenyl to the ketone-containing aromatic monomer is 1:1.1~1.4, wherein the concentration of p-terphenyl in the organic solvent is 0.6~1.2 mol L. -1 The superacid catalyst mentioned refers to a catalyst capable of catalyzing the reaction of ketone-containing aromatic monomers; the superacid catalyst is added dropwise at a temperature of 0-30℃; the mass ratio of the superacid catalyst to p-terphenyl is 8-12; and the stirring reaction time is 6-32 h.

6. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 5, characterized in that, The ketone-containing aromatic monomers are 2,2,2-trifluoroacetylbenzoic acid, 2,2,2-trifluoro-1-(4-(trifluoromethyl)phenyl)ethyl ketone, or 2,2,2,4'-tetrafluoroacetophenone.

7. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 5, characterized in that, The superacid catalyst is trifluoromethanesulfonic acid or trifluoroacetic acid; the concentration of the alkaline solution is 2~6 M; the alkali in the alkaline solution is potassium carbonate, sodium carbonate or sodium bicarbonate.

8. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 3, characterized in that, In the sulfonation reaction described above: the sulfonation temperature is 40-120℃, and the reaction time is 2-48 h; the drying temperature is 70-90℃, and the drying time is 12-24 h; the ion exchange capacity of the obtained sulfonated polyaryl polymer is 1.38-2.68 mmol g. -1 .

9. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 3, characterized in that, In the solution casting method described above: the mass concentration of the casting solution is 1~5 wt%, the organic solvent used in the casting solution is dimethyl sulfoxide, N-methylpyrrolidone or N,N-dimethylacetamide, the drying temperature is 70~90℃, and the drying time is 12-24 h.

10. The method for preparing a polyaryl ion-conducting membrane containing a double electron-withdrawing side chain structure according to claim 3, characterized in that, In the acidification process, the concentration of the H2SO4 solution is 2-5 M, and the soaking time is 12-36 h.

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