Novel ionic crosslinking type high-conductivity amphoteric membrane

Abstract

The invention relates to the technical field of electrochemistry, and discloses a novel ionic crosslinking type high-conductivity amphoteric membrane which comprises the following components in percentage by mass: 50% of side chain ionic crosslinking type fluorine-containing branched sulfonated polyimide, 25% of polybenzimidazole, 0.5%-1% of polydopamine functionalized carbon nanotubes, 5% of polyether amide and 5% of a siloxane durability improver. The polydopamine functionalized carbon nanotube can be replaced by a graphene oxide, the polydopamine functionalized carbon nanotube and the graphene oxide are both nanoscale fillers, and the ionic liquid is one of ethyl-3-methylimidazole sulfonate and a polymer electrolyte-based ionic liquid. By optimizing the proportion design of the ionic cross-linked membrane, the conductivity and chemical resistance can be improved by adding a conductive reinforcing agent such as polydopamine functionalized carbon nanotubes and a hydrophilic agent such as polyether amide, meanwhile, the high-temperature stability and ionic conduction performance are optimized, and the electrochemical application requirements are met.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemistry, in particular to a novel ion-crosslinked high-conductivity amphoteric membrane. Background Art

[0002] High conductivity membrane materials are widely used in new energy batteries, including conductive polymers, carbon nanomaterials and transparent conductive oxides. By doping to improve conductivity, these membranes can be used for electrode materials, electrolyte membranes and interface modification layers, significantly optimizing the battery's energy density, ion migration efficiency and interface stability, thereby improving battery performance and promoting the development of new energy technologies.

[0003] Most optimizations in existing technologies are mainly focused on a single performance aspect, such as conductivity, chemical corrosion resistance or high-temperature stability, but lack comprehensive consideration of the comprehensive optimization of multiple performances. In practical applications, ion-crosslinked membranes often need to have high conductivity, excellent chemical corrosion resistance and good high-temperature stability at the same time. The lack of comprehensive performance optimization leads to unsatisfactory performance in complex application environments, such as long-term stability or reduced efficiency under extreme conditions. At the same time, the current ion-crosslinked membrane technology lacks in-depth integration with actual application scenarios during design and optimization, such as differentiated requirements for specific applications such as batteries, electrolytes, and chemical reactors. This situation results in the developed membrane materials performing well in laboratory environments, but the challenges and demands encountered in practical applications cannot be effectively addressed, thereby limiting the commercialization and industrialization of the technology. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a novel ion-crosslinked high-conductivity amphoteric membrane, which solves the limitations of the prior art in single functional performance optimization and the lack of close integration with actual application scenarios.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a new type of ion-crosslinked high-conductivity amphoteric membrane, comprising the following components in mass percentage: 55% of side-chain ion-crosslinked fluorinated branched sulfonated polyimide, 25% of polybenzimidazole, 5% of polydopamine functionalized carbon nanotubes, 5% of polyetheramide, 5% of siloxane durability improver and 2% of ionic liquid.

[0006] Preferably, the ionic liquid is one of ethyl-3-methylimidazole sulfonate and a polymer electrolyte-based ionic liquid, and the ethyl-3-methylimidazole sulfonate is a sulfonate-type ionic liquid.

[0007] A method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane comprises the following steps:

[0008] S1. Material preparation and solution preparation: prepare the required main materials and select the required auxiliary materials;

[0009] S2, film forming process: put the prepared main materials and auxiliary materials into the mold in order to form;

[0010] S3, curing treatment: the film after film formation is cured by heat treatment or ultraviolet light irradiation. The heat treatment temperature and time are adjusted according to the thermal stability of the material to promote the cross-linking and crystallization of the material and enhance the mechanical properties and chemical stability of the film;

[0011] S4, acid soaking protonation treatment: After cleaning the membrane with deionized water, soak it in 1 mol L-1 sulfuric acid solution for 24 hours to completely exchange protons and convert the membrane into a proton type. Finally, soak the membrane in deionized water for 24 hours to fully remove the residual sulfuric acid solution on the membrane, and store it for subsequent testing;

[0012] S5. Performance testing and optimization: The prepared film is subjected to various performance tests, including but not limited to electrical conductivity, ion conductivity, mechanical strength, chemical corrosion resistance and thermal stability. The material ratio and preparation process are optimized according to the test results to achieve the best battery performance and long-term stability.

[0013] Preferably, the S1 comprises the following steps:

[0014] S1-1. Prepare the side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole solution: dissolve the side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole in an appropriate amount of organic solvent, respectively. The typical dissolution concentration is 55% (mass ratio) for the side chain ion cross-linked fluorinated branched sulfonated polyimide and 25% (mass ratio) for polybenzimidazole. Ensure that the solution is completely dissolved under appropriate temperature and stirring conditions to form a uniform solution;

[0015] S1-2, adding polydopamine functionalized carbon nanotubes or graphene oxide: gradually adding pre-dispersed polydopamine functionalized carbon nanotubes or graphene oxide to the side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole solution, the addition amount is about 0.2%-2% (mass ratio) of the total mass, after each addition, use a stirrer or ultrasonic treatment to ensure that the filler is evenly dispersed in the solution to avoid agglomeration;

[0016] S1-3, adding polyetheramide as a hydrophilic agent: adding polyetheramide as a hydrophilic agent to the above solution, the addition amount is about 5% (mass ratio) of the total mass, and polyetheramide helps to improve the hydration capacity and ion conductivity of the film;

[0017] S1-4. Add other functional materials: According to specific needs, gradually add siloxane durability improver, thermal stabilizer, ionic liquid or other nanoparticle filler, and gradually adjust according to the properties of each material and the recommended ratio.

[0018] Preferably, S2 comprises the following steps:

[0019] S2-1, film formation of the solution: pouring the mixed solution into a pre-prepared film-forming mold, or by coating, spin coating or casting;

[0020] S2-2. Solvent volatilization: Ensure that the solvent can fully evaporate during the film formation process. The volatilization of the solvent can be accelerated by placing it in a vacuum oven or in a ventilated environment to form a uniform and dense film structure.

[0021] Preferably, the suitable temperature for coating, spin coating or casting in the film formation of the solution is 60-80°C.

[0022] Preferably, the solvent volatilization stirring time is determined according to the viscosity and fluidity of the solution, the volatility of the solvent and the environmental conditions.

[0023] Preferably, the sulfonated polyimide has a sulfonation degree of 50%, and its preparation steps are as follows:

[0024] A. Sulfonation treatment: 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) is dissolved in concentrated sulfuric acid to carry out a sulfonation reaction to obtain sulfonated NTDA.

[0025] B. Dissolving and mixing: Dissolve 1,3,5-tris(2-trifluoromethyl-4-aminophenoxy)benzene (TFAPOB), 4,4'-diaminodiphenyl ether (ODA), disulfonic acid benzidine (BDSA) and sulfonated NTDA in a solvent according to a set molar ratio. The solvent can be dimethyl sulfoxide (DMSO) or dimethylformamide (DMF).

[0026] C. Polycondensation reaction: The mixed solution is heated to 80-120° C. to carry out polycondensation reaction. The branching degree of the final product is controlled by adjusting the molar ratio of TFAPOB to ODA. The branching degree ranges from 4 to 12%.

[0027] D. Film formation: After the reaction is completed, the obtained sulfonated polyimide resin solution is cooled to room temperature, and the solvent is evaporated or vacuum dried to obtain the sulfonated polyimide resin for later blending and solution preparation.

[0028] E. Post-treatment: Clean the resin polymer to remove residual solvent and unreacted monomer.

[0029] F. Characterization and analysis: The final product is characterized by nuclear magnetic resonance (NMR), infrared spectroscopy (FT IR), etc. to confirm its degree of sulfonation and degree of branching, and its performance indicators such as mechanical properties and ionic conductivity are tested.

[0030] The present invention provides a novel ion-crosslinked high-conductivity amphoteric membrane having the following beneficial effects:

[0031] 1. The present invention comprises a basic ratio of side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole, and successfully integrates polydopamine functionalized carbon nanotubes and polyetheramide. The polydopamine functionalized carbon nanotubes as a conductive enhancer not only improve the conductivity of the film, but also enhance its mechanical properties, which helps to maintain stability under complex stress. At the same time, the addition of polyetheramide as a hydrophilic agent improves the hydration capacity and ion conductivity of the membrane, thereby enhancing the reliability and efficiency of the membrane in battery and electrolyte applications. By optimizing the ratio of these key components, it can be ensured that the ion cross-linked membrane performs well in high energy density batteries and other electrochemical devices, providing reliable basic material support for the development of new energy technologies.

[0032] 2. The present invention can effectively enhance the membrane's resistance to chemical corrosion and extend its service life by adding a siloxane durability improver. At the same time, by appropriately adjusting the proportion of ionic liquids, the membrane's ion conductivity can be further improved to ensure that high efficiency can be maintained under complex operating conditions. This combination optimization is not only applicable to fuel cells and electrolyte membranes, but can also play an important role in special reactors and electrochemical reactors in the chemical industry, bringing more reliable and stable solutions to industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1: Ion-crosslinked membrane for high conductivity batteries

[0036] Material ratio: side chain ion cross-linked fluorinated branched sulfonated polyimide: 60%, polybenzimidazole: 30%, polydopamine functionalized carbon nanotubes PDA: 5% and polyetheramide: 5%

[0037] Implementation steps:

[0038] S1. Solution preparation:

[0039] S1-1. Dissolve the side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole in NMP at a ratio of 60% and 30%, ensuring that they are completely dissolved and form a uniform solution.

[0040] S1-2, gradually add the pre-dispersed polydopamine functionalized carbon nanotubes into the solution, the amount added is 5% of the total mass. Use a stirrer to ensure that the filler is evenly dispersed

[0041] S1-3, add polyether amide as a hydrophilic agent, accounting for 5% of the total mass, and continue stirring until evenly mixed

[0042] S2. Film forming process:

[0043] S2-1, pour the solution into the film-forming mold, and form the film at a temperature of 80°C by coating or spin coating.

[0044] S2-2. Ensure that the solvent can fully evaporate to form a uniform and dense membrane structure

[0045] S3. Curing treatment: The formed film is placed in an oven at 120°C for curing for 4 hours to promote cross-linking and crystallization of the material.

[0046] S4, acid soaking protonation treatment: After cleaning the membrane with deionized water, soak it in 1 mol L-1 sulfuric acid solution for 24 hours to completely exchange protons and convert the membrane into a proton type. Finally, soak the membrane in deionized water for 24 hours to fully remove the residual sulfuric acid solution on the membrane, and store it for subsequent testing.

[0047] S5. Performance testing and optimization: Test the conductivity, ion conductivity and mechanical strength of the film, and optimize the preparation process based on the test results to achieve the best battery performance and stability

[0048] Example 2: Ion-crosslinked membrane for high temperature stability fuel cell

[0049] Material ratio: side chain ion cross-linked fluorinated branched sulfonated polyimide: 50%, polybenzimidazole: 35%, graphene oxide: 5%, polyether amide: 5% and siloxane durability improver: 5%

[0050] Implementation steps:

[0051] S1. Solution preparation:

[0052] S1-1. Dissolve the side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole in DMF at a ratio of 50% and 35%, ensuring complete dissolution.

[0053] S1-2, gradually add graphene oxide as a conductive enhancer, accounting for 5% of the total mass, and use ultrasonic treatment to ensure uniform dispersion

[0054] S1-3, add polyether amide and siloxane durability improver, each accounting for 5% of the total mass, and continue stirring until evenly mixed.

[0055] S2. Film forming process:

[0056] S2-1, pour the solution into the mold by casting method, and form a film at a temperature of 80℃

[0057] S2-2. Control humidity and solvent volatilization to form a dense membrane structure

[0058] S3, curing treatment: Use ultraviolet light irradiation to cure the film to ensure the cross-linking and crystallization of the material

[0059] S4. Performance testing and optimization: Test the thermal stability, ion conductivity and chemical corrosion resistance of the film at high temperature, and optimize the ratio and process parameters according to the test results to improve the efficiency and durability of the fuel cell

[0060] Example 3: Medical ion-crosslinked membrane with enhanced antibacterial properties

[0061] Material ratio: side chain ion cross-linked fluorinated branched sulfonated polyimide: 55%, polybenzimidazole: 25%, polydopamine functionalized carbon nanotubes: 7%, polyetheramide: 3%, nanosilver particles: 5% and polyvinyl alcohol (PVA): 5%

[0062] Implementation steps:

[0063] S1. Solution preparation:

[0064] S1-1. Dissolve the side chain ion cross-linked fluorinated branched sulfonated polyimide and polybenzimidazole in NMP at a ratio of 55% and 25%, and stir until completely dissolved.

[0065] S1-2, add pre-dispersed polydopamine functionalized carbon nanotubes and silver nanoparticles, accounting for 7% and 5% of the total mass respectively, to ensure uniform dispersion

[0066] S1-3, add polyetheramide and PVA as reinforcing agents, accounting for 3% and 5% of the total mass respectively, and continue stirring until uniformly mixed.

[0067] S2. Film forming process:

[0068] S2-1, use the coating method to apply the solution on the surface, and control the coating thickness and temperature to ensure the uniformity of the film

[0069] S2-2, film formation is carried out at a temperature of 70°C to ensure that the surface of the film is smooth and uniform after formation

[0070] S3, curing treatment: placing the film after film formation in a UV irradiation device for UV curing treatment

[0071] S4. Performance testing and optimization: Test the antibacterial properties, mechanical strength and hydration capacity of the film, adjust the ratio and preparation process according to the test results, and optimize the application performance and stability of the film

[0072] Comparative Examples 1-3:

[0073] Comparative Example 1: The difference from the example is that polydopamine functionalized carbon nanotubes and polyetheramide are not used, and the remaining steps are the same. Material ratio: 65% of side chain ion cross-linked fluorinated branched sulfonated polyimide and 35% of polybenzimidazole

[0074] Comparative Example 2: The difference from the example is that the siloxane durability improver and polydopamine functionalized carbon nanotubes are not used, and the other steps are the same. Material ratio: 50% of side chain ion cross-linked fluorinated branched sulfonated polyimide, 35% of polybenzimidazole, 5% of polyetheramide and 10% of ionic liquid

[0075] Comparative Example 3: The difference from the example is that no silver nanoparticles are used, and the remaining steps are the same. Material ratio: 60% of side chain ion cross-linked fluorinated branched SPI, 30% of polybenzimidazole and polydopamine functionalized carbon nanotubes

[0076] Experimental Group 1: Baseline Ratio (Example 1)

[0077] Material ratio:

[0078] Side chain ion cross-linked fluorinated branched SPI: 60%

[0079] Polybenzimidazole: 30%

[0080] Polydopamine functionalized carbon nanotubes: 5%

[0081] Polyetheramide: 5%

[0082] Experimental Group 2: Removal of polyetheramide and polydopamine functionalized carbon nanotubes (variation of Example 1)

[0083] Material ratio:

[0084] Side chain ion cross-linked fluorinated branched SPI: 65%

[0085] Polybenzimidazole: 35%

[0086] Experimental Group 3: Removal of Siloxane Durability Improver and Graphene Oxide (Variation of Example 2)

[0087] Material ratio:

[0088] Side chain ion cross-linked fluorinated branched SPI: 50%

[0089] Polybenzimidazole: 35%

[0090] Polyetheramide: 5%

[0091] Ionic liquid: 10%

[0092] Experimental Group 4: Removal of Nanosilver Particles and PVA (Variation of Example 3)

[0093] Material ratio:

[0094] Side chain ion cross-linked fluorinated branched SPI: 60%

[0095] Polybenzimidazole: 30%

[0096] Polydopamine functionalized carbon nanotubes: 10%

[0097] Expected results and analysis:

[0098] Comparison of electrical conductivity and ion conduction performance:

[0099] Experimental group 1 vs. experimental group 2:

[0100] It is expected that the conductivity and ion conduction performance of experimental group 1 (containing polyetheramide and polydopamine functionalized carbon nanotubes) will be better than those of experimental group 2. The addition of polyetheramide enhances the hydration capacity and ion conductivity of the membrane, while polydopamine functionalized carbon nanotubes improve the electrical conductivity, so experimental group 1 performs better in electrochemical applications.

[0101] Experimental group 1 vs. experimental group 3:

[0102] Experimental Group 1 and Experimental Group 3 are similar in conductivity, but Experimental Group 3 is slightly inferior to Experimental Group 1 in chemical corrosion resistance. Experimental Group 3 lacks the siloxane durability improver, resulting in poor stability under strong acid and alkali conditions.

[0103] Comparison of thermal stability and durability:

[0104] Experimental group 2 vs. experimental group 3:

[0105] Experimental Group 2 performed better in thermal stability than Experimental Group 3 because Experimental Group 3 removed the siloxane durability improver, which resulted in decreased performance in high temperature environments.

[0106] Comparison of antibacterial properties and medical applications:

[0107] Experimental group 1 vs. experimental group 4:

[0108] The antibacterial properties of experimental group 4 (without nanosilver particles and PVA) were inferior to those of experimental group 1. Nanosilver particles have good antibacterial properties, and their removal leads to a decrease in the long-term stability of the film in medical applications.

[0109] The experimental data are shown in Table 1:

[0110] Table 1:

[0111]

[0112]

[0113] Experimental data analysis:

[0114] Electrical conductivity and ion conduction properties:

[0115] Experimental group 1 (baseline ratio) exhibited the highest electrical conductivity and ion conduction performance, which was attributed to the reinforcing effect of polydopamine-functionalized carbon nanotubes and polyetheramide.

[0116] The electrical conductivity and ion conduction performance of Experimental Groups 2 and 3 are related to the removal of the conductivity enhancer and the hydrophilic agent.

[0117] Thermal stability:

[0118] Experimental Groups 1 and 4 performed better in thermal stability, which was partly attributed to the addition of heat-resistant materials or components with good thermal stability (such as polydopamine-functionalized carbon nanotubes and silver nanoparticles).

[0119] Chemical resistance:

[0120] The chemical corrosion resistance of experimental group 1 is better, mainly due to the addition of siloxane durability improver.

[0121] Experimental Group 3 showed lower chemical resistance due to the removal of the siloxane durability improver.

[0122] Antimicrobial properties:

[0123] Only experimental group 1 and experimental group 4 added nanosilver particles, so only these two groups showed good antibacterial properties. Experimental group 4 performed slightly worse than experimental group 1 in this regard.

[0124] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A novel ion-crosslinked high-conductivity amphoteric membrane, characterized in that: The invention comprises the following components in percentage by mass: 50% of side chain ion cross-linked fluorine-containing branched sulfonated polyimide, 25% of polybenzimidazole, 5% of polydopamine functionalized carbon nanotube, 5% of polyether amide and 5% of siloxane durability improver.

2. A novel ion-crosslinked high-conductivity amphoteric membrane according to claim 1, characterized in that: The polydopamine functionalized carbon nanotubes can be replaced by graphene oxide, and both the polydopamine functionalized carbon nanotubes and graphene oxide are nanoscale fillers.

3. A novel ion-crosslinked high-conductivity amphoteric membrane according to claim 1, characterized in that: The ionic liquid is one of ethyl-3-methylimidazole sulfonate and a polymer electrolyte-based ionic liquid, and the ethyl-3-methylimidazole sulfonate is a sulfonate-type ionic liquid.

4. A method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane, used for preparing a novel ion-crosslinked high-conductivity amphoteric membrane as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Material preparation and solution preparation: prepare the required main materials and select the required auxiliary materials; S2, film forming process: put the prepared main materials and auxiliary materials into the mold in order to form; S3, curing treatment: the film after film formation is cured by heat treatment or ultraviolet light irradiation; the heat treatment temperature and time are adjusted according to the thermal stability of the material to promote the cross-linking and crystallization of the material and enhance the mechanical properties and chemical stability of the film; S4, acid soaking protonation treatment: After cleaning the membrane with deionized water, soak it in a 1 mol L-1 sulfuric acid solution for 24 hours to completely exchange protons and convert the membrane into a proton type. Finally, soak the membrane in deionized water for 24 hours to fully remove the residual sulfuric acid solution on the membrane, and store it for subsequent testing; S5. Performance testing and optimization: The prepared film is subjected to various performance tests, including but not limited to electrical conductivity, ion conductivity, mechanical strength, chemical corrosion resistance and thermal stability. The material ratio and preparation process are optimized according to the test results to achieve the best battery performance and long-term stability.

5. The method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane according to claim 4, characterized in that: The S1 comprises the following steps: S1-1, prepare side chain ion crosslinked fluorinated branched polyarylethersulfone and polybenzimidazole solution: dissolve side chain ion crosslinked fluorinated branched polyarylethersulfone and polybenzimidazole in appropriate amounts of organic solvents m-cresol and benzoic acid, respectively, with typical dissolution concentrations of side chain ion crosslinked fluorinated branched polyarylethersulfone: 55% (mass ratio), polybenzimidazole: 25% (mass ratio), ensure complete dissolution under appropriate temperature and stirring conditions to form a uniform solution; S1-2, adding polydopamine functionalized carbon nanotubes or graphene oxide: gradually adding the pre-dispersed polydopamine functionalized carbon nanotubes or graphene oxide to the side chain ion cross-linked fluorinated branched polyarylethersulfone and polybenzimidazole solution, the addition amount is about 0.2-2% (mass ratio) of the total mass, after each addition, using a stirrer or ultrasonic treatment to ensure that the filler is evenly dispersed in the solution to avoid agglomeration; S1-3, adding polyetheramide as a hydrophilic agent: adding polyetheramide as a hydrophilic agent to the above solution, the addition amount is about 5% (mass ratio) of the total mass, and polyetheramide helps to improve the hydration capacity and ion conductivity of the film; S1-4. Add other functional materials: According to specific needs, gradually add siloxane durability improvers, ionic liquids or other nanoparticle fillers, and gradually adjust according to the properties of each material and the recommended ratio.

6. The method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane according to claim 4, characterized in that: The S2 comprises the following steps: S2-1, film formation of the solution: pouring the mixed solution into a pre-prepared film-forming mold, or by coating, spin coating or casting; S2-2. Solvent volatilization: Ensure that the solvent can fully evaporate during the film formation process. The volatilization of the solvent can be accelerated by placing it in a vacuum oven or in a ventilated environment to form a uniform and dense film structure.

7. The method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane according to claim 6, characterized in that: The suitable temperature for film formation of the solution by coating, spin coating or casting is 60-80°C.

8. The method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane according to claim 7, characterized in that: The solvent volatilization stirring time is determined according to the viscosity and fluidity of the solution, the volatility of the solvent and the environmental conditions.

9. The method for preparing a novel ion-crosslinked high-conductivity amphoteric membrane according to claim 7, characterized in that: The sulfonated polyimide has a sulfonation degree of 50% and is prepared as follows: A. Sulfonation treatment: 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) is dissolved in concentrated sulfuric acid to carry out a sulfonation reaction to obtain sulfonated NTDA. B. Dissolving and mixing: Dissolve 1,3,5-tris(2-trifluoromethyl-4-aminophenoxy)benzene (TFAPOB), 4,4'-diaminodiphenyl ether (ODA), disulfonic acid benzidine (BDSA) and sulfonated NTDA in a solvent according to a set molar ratio. The solvent can be dimethyl sulfoxide (DMSO) or dimethylformamide (DMF). C. Polycondensation reaction: The mixed solution is heated to 80-120° C. to carry out polycondensation reaction. The branching degree of the final product is controlled by adjusting the molar ratio of TFAPOB to ODA. The branching degree ranges from 4 to 12%. D. Film formation: After the reaction is completed, the obtained sulfonated polyimide resin solution is cooled to room temperature, and the solvent is evaporated or vacuum dried to obtain the sulfonated polyimide resin for later blending and solution preparation. E. Post-treatment: Clean the resin polymer to remove residual solvent and unreacted monomers, and then dry it. F. Characterization and analysis: The final product is characterized by nuclear magnetic resonance (NMR), infrared spectroscopy (FTIR), etc. to confirm its degree of sulfonation and degree of branching, and its performance indicators such as mechanical properties and ionic conductivity are tested.

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