Aromatic quinine onium side chain functionalized quinine-aromatic copolymer and preparation method thereof

Abstract

The invention relates to the technical field of fuel cells and water electrolysis hydrogen production, in particular to an aromatic quinine onium side chain functionalized quinine-aromatic copolymer and a preparation method thereof. The quinine-arene copolymer with the functionalized arene quinine onium side chain provided by the invention has the following repetitive units: by introducing an arene quinine onium group structure on a main chain quinine structure of an ether-bond-free quinine arene copolymer, the ion capacity of the polymer can be increased, and the ion conductivity can be improved; physical crosslinking can be enhanced through the pi-pi action between side-chain aromatic hydrocarbons, the mechanical property and chemical stability of the copolymer are improved, the swelling degree of an ion exchange membrane is reduced, an ionic conduction channel is constructed through an aromatic quinine onium side chain of a macrocyclic structure, and the phase separation structure of the ion membrane is improved, so that the comprehensive performance of the polyaromatic quinine copolymer is improved.

Description

Technical Field

[0001] This invention relates to the fields of fuel cell and water electrolysis for hydrogen production, and specifically to a quinine-aromatic copolymer with a quinine-onium side chain functionalized and its preparation method. Background Technology

[0002] Anion exchange membranes have wide applications in numerous electrochemical devices, such as water electrolysis for hydrogen production, alkaline fuel cells, flow batteries, and electrodialysis units. Their unique ability to selectively conduct anions enables the efficient and orderly transport of ions within these devices, thus ensuring stable operation and high performance.

[0003] For example, the three currently used room-temperature water electrolysis hydrogen production technologies include alkaline aqueous solution electrolysis (ALK), cation exchange membrane electrolysis (PEM-WE), and anion exchange membrane electrolysis (AEM-WE). The AEM-WE electrolyzer has a similar structure to the PEM-WE electrolyzer, mainly consisting of an anion exchange membrane and two transition metal catalytic electrodes. It typically uses pure water or a low-concentration alkaline solution as the electrolyte. The anion exchange membrane (AEM) is a crucial component of the AEM-WE and AEM-FC systems, its function being to conduct OH- ions from the cathode to the anode while simultaneously preventing direct transfer of gas and electrons between the electrodes.

[0004] The performance evaluation of anion exchange membranes is primarily based on three key indicators: ionic conductivity, chemical stability, and mechanical strength. Ionic conductivity is a crucial indicator of a membrane material's ability to conduct ions, directly impacting the ion transport rate and efficiency in electrochemical devices. Chemical stability determines whether the membrane material can maintain its original structure and performance under prolonged operation and harsh environments. Mechanical strength is a key factor in whether the membrane material can withstand external pressure and deformation, maintaining its integrity and lifespan. However, simultaneously meeting all three performance indicators undoubtedly presents a significant challenge for the development of anion exchange membranes.

[0005] Chinese patent application CN117106161A, published on November 24, 2023, discloses a polyarylquinine polymer, a preparation method, and a prepared anion exchange membrane. By adopting a full carbon chain framework structure and introducing a more stable functional cationic quinine ring structure as an anion conducting group, and by using strategies such as copolymerization with hydrophobic units, hyperbranching, and crosslinking to modify the polymer, it can achieve a lower water absorption rate and swelling rate, which can further improve the mechanical stability and conductivity of the AEM. It can be used to prepare anion exchange membranes with high stability.

[0006] However, the aforementioned polyarylequinine polymers cannot achieve a synergistic improvement in mechanical properties, ionic conductivity, chemical stability, swelling degree, and water absorption rate when used as anion exchange membranes. Summary of the Invention

[0007] The purpose of this invention is to provide a quinine-aromatic copolymer with a functionalized aromatic quinine side chain, which solves the problem that existing polyarylequinine polymers cannot synergistically improve mechanical properties, ionic conductivity, chemical stability, swelling degree, and water absorption rate when used as anion exchange membranes.

[0008] The second objective of this invention is to provide a method for preparing quinine-aromatic copolymers with arylquinine side chains functionalized, thereby solving the problem that existing polyarylquinine polymers cannot synergistically improve mechanical properties, ionic conductivity, chemical stability, swelling degree, and water absorption rate when used as anion exchange membranes.

[0009] To solve the above-mentioned technical problems, the technical solution of the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization of the present invention is as follows:

[0010] A quinine-aromatic copolymer with a quinine-onium side chain functionalized has the following repeating units:

[0011]

[0012] The structural formula of the side chain is as follows:

[0013]

[0014] Where Ar1 is the first phenyl structural unit, Ar2 is the second phenyl structural unit; R1 is the multifunctional structural unit, R2 is the third phenyl structural unit; x1+y+x2=100%, x1, y≠0, n is selected from integers from 1 to 10, and Z is 0 or 1; when Z=0, the multifunctional structural unit includes one or more of fluoromethylbenzene, haloalkyl, alkyl, fatty acid, nitrobenzene, and benzonitrile; when Z=1, the multifunctional structural unit includes one or two of tertiary amine groups and secondary amine groups.

[0015] This invention improves upon existing technologies by providing a quinine-aromatic copolymer with aromatic quinine onion side chains. By introducing an aromatic quinine onion group structure into the main chain quinine structure of the ether-free quinine-aromatic copolymer, this side chain structure not only increases the polymer's ion capacity and improves ion conductivity, but also enhances physical cross-linking through π-π interactions between the aromatic side chains. This improves the copolymer's mechanical properties and chemical stability, reduces the swelling degree of the ion exchange membrane, and constructs ion conduction channels through the macrocyclic aromatic quinine onion side chains, thereby improving the phase separation structure of the ion exchange membrane and ultimately enhancing the overall performance of the polyaromatic quinine copolymer.

[0016] The quinine-aromatic copolymer with aromatic quinine-onium side chain functionalization provided by this invention has an ion exchange capacity of 2 mmol·g. -1 The above-mentioned anion exchange membranes exhibit a swelling degree of less than 4.10% and a water absorption rate of less than 11.86% at 80℃. In a dry state, the membranes achieve a tensile strength of over 49 MPa and an elongation at break of over 10%. In a fully wetted state, the membranes achieve a tensile strength of over 33 MPa and an elongation at break between 15.58% and 22.96%, while also demonstrating elasticity and flexibility. At 80℃, the OH... - The conductivity reaches 76 mS / cm -1 The chloride ion conductivity reaches 39 mS / cm. -1 The above describes the process of soaking in 2.0M NaOH at 80℃ for 3000 hours, resulting in OH... - The conductivity retention rate reaches over 77%, and the current density in the anion exchange membrane water electrolysis device reaches 0.07 A·cm. -2 @2.0V and above, ohmic resistance is less than 0.72Ω·cm 2 .

[0017] Preferably, n is selected from an integer between 5 and 7.

[0018] Preferably, Choose one of the following structural formulas:

[0019] Preferably, Ar1 and Ar2 are each independently selected from at least one of the following structures:

[0020]

[0021] The R2 is selected from at least one of the third phenyl structural units of the following structures:

[0022]

[0023] It is understandable that Ar1 and Ar2 can be the same or different.

[0024] Preferably, the aromatic quinine-aromatic copolymer with side-chain functionalization has one of the following repeating units:

[0025]

[0026] The technical solution for preparing quinine-aromatic copolymers with aromatic quinine onion side chains provided by this invention is as follows:

[0027] A method for preparing a quinine-aromatic copolymer with a quinine-onium side chain functionalized includes the following steps: according to the structure of the quinine-onium side chain functionalized quinine-aromatic copolymer, a first phenyl structural unit Ar1, a second phenyl structural unit Ar2, 3-quinine cyclic ketone hydrochloride, a multifunctional structural unit R1 containing a ketone or aldehyde group, and a first catalyst are subjected to a first Friedel-Crafts hydroxyalkylation reaction in a first solvent to obtain a long-chain copolymer; the long-chain copolymer, the side chain halide, and iodomethane are subjected to a Mensøe-Gold reaction in a second solvent to obtain the quinine-onium side chain functionalized quinine-aromatic copolymer.

[0028] The method for preparing quinine-aromatic copolymers with quinine-onium side chains provided by the present invention is obtained by Friedel-Crafts hydroxyalkylation reaction and Mensøe reaction. The preparation process is simple and suitable for large-scale production.

[0029] Preferably, the side chain halide is obtained by performing a second Friedel-Crafts hydroxyalkylation reaction on a haloquinine salt, a third phenyl structural unit R2, and a second catalyst in a third solvent; the haloquinine salt is obtained by reacting a 1,n-dihaloalkyl hydrocarbon and a 3-quinine cycloketone in a fourth solvent, wherein n is selected from an integer from 1 to 10, and the number of carbon atoms in the alkyl hydrocarbon is n.

[0030] Preferably, the haloquinine salt is obtained by adding a 1,n-dihaloalkyl hydrocarbon solution dropwise to a 3-quinine cycloketone solution and reacting at 30–60°C for 24–72 h; the temperature of the second Friedel-Crafts hydroxyalkylation reaction is 0–25°C, and the time of the second Friedel-Crafts hydroxyalkylation reaction is 4–16 h.

[0031] Preferably, the molar ratio of haloquinine salt to the third phenyl structural unit R2 is (2-3):(5-6); and the molar ratio of 1,n-dihaloalkyl hydrocarbon to 3-quinine cycloketone is (25-30):1.

[0032] Preferably, the molar ratio of the first phenyl structural unit Ar1, the second phenyl structural unit Ar2, 3-quinine cycloketone hydrochloride, and the multifunctional structural unit containing a ketone or aldehyde group is (1-1.1):(1-1.1):(1-1.5):(1-1.2); and the mass ratio of the long-chain copolymer to the side chain halide is (0.3-0.4):(0.2-0.6).

[0033] Preferably, the multifunctional structural unit containing a ketone or aldehyde group is selected from one or more compounds comprising the following structural formulas:

[0034]

[0035] Where m is selected from integers from 1 to 5. Attached Figure Description

[0036] Figure 1 For PBQIS 1 H NMR spectrum;

[0037] Figure 2 For DBCQ 1 H NMR spectrum;

[0038] Figure 3 The quinine-aromatic copolymer PBQIS-BQA, which is functionalized with aromatic quinine-onium side chains according to the present invention, is... 1 H NMR spectrum;

[0039] Figure 4 The quinine-aromatic copolymer PBQIS-DBCQ, which is functionalized with the aromatic quinine-onium side chain of the present invention, is... 1 H NMR spectrum;

[0040] Figure 5 These are the molecular weight test results from PBQIS.

[0041] Figure 6 The swelling degree and water absorption rate test results are for PBQIS-BQA and PBQIS-DBCQ.

[0042] Figure 7 The water contact angle (WCA) test results of the anion exchange membrane made of quinine-aromatic copolymer with aromatic quinine side chain functionalization according to the present invention;

[0043] Figure 8 Figure 1 shows the tensile strength and elongation at break test results of the anion exchange membrane made of quinine-aromatic copolymer functionalized with aromatic quinine side chain of the present invention.

[0044] Figure 9 A folded and unfolded photograph of the PBQIS series membrane;

[0045] Figure 10 This is a graph showing the thermogravimetric changes of the PBQIS series membranes of the present invention.

[0046] Figure 11 The graph shows the test results of hydroxide ion conductivity of the PBQIS-BQA and PBQIS-DBCQ membranes of the present invention.

[0047] Figure 12 The graph shows the chloride ion conductivity test results of the PBQIS-BQA and PBQIS-DBCQ membranes of the present invention.

[0048] Figure 13 The graph shows the test results of hydroxide ion conductivity of the PBPA-DBCQ, PBIM-DBCQ and PBPy-DBCQ membranes of the present invention.

[0049] Figure 14 The graph shows the alkali resistance stability test results of the PBQIS-BQA and PBQIS-DBCQ membranes of the present invention.

[0050] Figure 15 The polarization curves of the PBQIS-BQA and PBQIS-DBCQ films of the present invention are shown below.

[0051] Figure 16 The graph shows the ohmic resistance test results of the electrolyzer assembled with the PBQIS-BQA and PBQIS-DBCQ membranes of the present invention.

[0052] Figure 17 The graphs show the two-electrode stability of the PBQIS-BQA and PBQIS-DBCQ films of the present invention. Detailed Implementation

[0053] The technical concept of the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization provided by the present invention is as follows:

[0054] Existing quinine-aromatic copolymers with quinine-onium side chain functionalization employ a full carbon chain backbone structure. By introducing a more stable functional cationic quinine ring structure as an anion-conducting group, and by using strategies such as copolymerization with hydrophobic units, hyperbranching, and crosslinking to modify the polymer, its water absorption and swelling rate are reduced, thereby improving mechanical stability and electrical conductivity. Alternatively, patent CN119529243A introduces cationic groups with high alkali resistance into the polyaryl polymer structure, and simultaneously introduces cationic side chains to improve its ionic conductivity and alkali resistance. However, none of the above methods can synergistically improve mechanical properties, ionic conductivity, chemical stability, swelling rate, and water absorption rate.

[0055] The quinine-aromatic copolymers of the present invention, which are functionalized with aromatic quinine ononium side chains, can synergistically improve their mechanical properties, ionic conductivity, chemical stability, swelling degree, and water absorption rate by introducing arylquinine ononium structural side chains into the quinine-aromatic copolymer structure.

[0056] The method for preparing the aromatic quinine-aromatic copolymer with side chain functionalization of the present invention includes the following steps:

[0057] 1) According to the structure of the quinine-aromatic copolymer with side chain functionalization of aromatic quinine, a first phenyl structural unit Ar1, a second phenyl structural unit Ar2, 3-quinine cyclic ketone hydrochloride, a multifunctional structural unit R1 containing a ketone or aldehyde group, and a first catalyst are subjected to a first Friedel-Crafts hydroxyalkylation reaction in a first solvent to obtain a long-chain copolymer.

[0058] In step 1), the molar ratio of the first phenyl structural unit Ar1, the second phenyl structural unit Ar2, 3-quinine cycloketone hydrochloride, and the multifunctional structural unit containing a ketone or aldehyde group is (1-1.1):(1-1.1):(1-1.5):(1-1.2).

[0059] It is understandable that the first phenyl structural unit Ar1 and the second phenyl structural unit Ar2 can be selected from phenyl structural units with the same structure. When both are the first phenyl structural unit Ar1, the molar ratio of the first phenyl structural unit Ar1, 3-quinine cycloketone hydrochloride, and multifunctional structural units containing ketone or aldehyde groups is (2~2.2):(1~1.5):(1~1.2).

[0060] In step 1), when all components are first phenyl structural units Ar1, the first Friedel-Crafts hydroxyalkylation reaction involves reacting the first phenyl structural unit Ar1, 3-quinine cycloketone hydrochloride, and the first catalyst 1 in the first solvent 1 at 0–5°C, followed by adding a multifunctional structural unit containing a ketone or aldehyde group, the first catalyst 2, and the first solvent 2 to carry out a second reaction. When the first Friedel-Crafts hydroxyalkylation reaction reaches a point where the reaction system becomes viscous and cannot be stirred, the system is placed in a first alkaline solution to precipitate, the catalyst is removed by stirring, filtered, and dried to obtain a long-chain copolymer.

[0061] Specifically, the first Friedel-Crafts hydroxyalkylation reaction involves thoroughly mixing a solution of the first phenyl structural unit Ar1 and a solution of 3-quinine cyclic ketone hydrochloride at 0–5°C, followed by the addition of a first catalyst 1 to carry out the first reaction. The solvents for both the first phenyl structural unit Ar1 solution and the 3-quinine cyclic ketone hydrochloride solution are the first solvent 1.

[0062] In step 1), the multifunctional structural unit containing a ketone or aldehyde group is selected from one or more compounds containing the following structural formulas:

[0063]

[0064] Where m is selected from integers from 1 to 5.

[0065] It should be noted that the ketone group in the multifunctional structural unit containing ketone or aldehyde groups participates in the reaction. When the multifunctional structural unit containing ketone or aldehyde groups does not contain tertiary or secondary amine groups (e.g., the first 7 in the above structural formula), the multifunctional structural unit R1 in the quinine-aromatic copolymer with side chain functionalization of aromatic quinine in the reaction includes one or more of fluoromethylbenzene, haloalkyl, alkyl, fatty acid, nitrobenzene, and benzonitrile, and Z = 0. When the multifunctional structural unit containing ketone or aldehyde groups contains tertiary or secondary amine groups (e.g., the last 9 in the above structural formula), Z = 1, and the N element of the tertiary or secondary amine group in the multifunctional structural unit R1 is grafted with a side chain.

[0066] In step 1), the first reaction takes 24–30 hours, and the second reaction takes 8–10 hours. It should be noted that the first reaction time refers to the reaction time after the addition of the first catalyst.

[0067] In step 1), the first catalyst 1 is composed of trifluoromethanesulfonic anhydride and trifluoroacetic acid in a volume ratio of (8-10):1, and (1-2) mL of the first catalyst 1 is added for every 1 mmol of the first phenyl structural unit Ar1; the first catalyst 2 is trifluoromethanesulfonic anhydride, and (0.2-0.5) mL of the first catalyst 2 is added for every 1 mmol of the first phenyl structural unit Ar1.

[0068] In step 1), 1 to 2 mL of first solvent 1 and 0.3 to 0.5 mL of first solvent 2 are added for every 1 mmol of the first phenyl structural unit Ar1.

[0069] In step 1), both the first solvent 1 and the first solvent 2 are dichloromethane.

[0070] In step 1), both the first phenyl structural unit Ar1 and the first phenyl structural unit Ar2 are biphenyls, and the multifunctional structural unit containing a ketone or aldehyde group is selected from one of indole-2,3-dione (indigo), pyruvic acid, imidazole-2-carboxaldehyde, and pyridine-4-carboxaldehyde.

[0071] In step 1), the first alkaline solution is a 1-2M Na2CO3, NaHCO3, or NaOH solution. Precipitation in the first alkaline solution involves stirring the product in the first alkaline solution to obtain a fibrous polymer for 10-24 hours.

[0072] In step 1), the number-average molecular weight of the long-chain polymer is 30–100 kDa, and the weight-average molecular weight is 30–100 kDa. The intrinsic viscosity of the prepared long-chain polymer in N-methylpyrrolidone (NMP) is 0.5–3 dL / g (25°C).

[0073] 2) The long-chain copolymer, the side-chain side halide and iodomethane were subjected to the Menshoukin reaction in a second solvent to obtain a quinine-aromatic copolymer with a quinine-onium side chain functionalized.

[0074] In step 2), the mass ratio of the long-chain copolymer to the side chain halide is (0.3-0.4):(0.2-0.6); 0.3-0.5 mL of iodomethane is added for every 0.3-0.4 g of long-chain copolymer.

[0075] In step 2), the Menxiujin reaction involves a third reaction in a second solvent involving the long-chain copolymer and the side halide; followed by the addition of iodomethane for a fourth reaction under dark conditions.

[0076] In step 2), the temperature of the third and fourth reactions is 50-60℃, the time of the third reaction is 18-36h, and the time of the fourth reaction is 16-24h.

[0077] In step 2), the second solvent is a mixed solvent formed by dimethyl sulfoxide and N-methylpyrrolidone in a volume ratio of 1:(0.5-2); 8-12 mL of the second solvent is added for every 0.3-0.4 g of long-chain copolymer.

[0078] In step 2), the material obtained after the reaction of the quinoline is placed in ethyl acetate to precipitate a crude product, which is then washed, filtered, and dried to obtain a quinoline-aromatic copolymer with a quinoline-onium side chain functionalization.

[0079] In step 2), the side-chain halide is obtained by reacting a haloquinine salt, a third phenyl structural unit R2, and a second catalyst in a third solvent at 0–25°C with a second Friedel-Crafts hydroxyalkylation reaction. The haloquinine salt is obtained by reacting a 1,n-dibromoalkyl hydrocarbon and a 3-quinine cycloketone in a fourth solvent, where n is selected from an integer from 1 to 10, and the alkyl hydrocarbon has n carbon atoms. After the second Friedel-Crafts hydroxyalkylation reaction is completed, the halide is precipitated in a second alkaline solution under icing conditions, the second catalyst is removed by stirring, filtered, and dried to obtain the side-chain halide.

[0080] Specifically, the second Friedel-Crafts hydroxyalkylation reaction involves fully dissolving the haloquinine salt and the third phenyl structural unit R2 in a third solvent at 0–25°C, and then adding a second catalyst to carry out the second Friedel-Crafts hydroxyalkylation reaction.

[0081] In step 2), the molar ratio of haloquinine salt to the third phenyl structural unit R2 is (2-3):(5-6).

[0082] In step 2), the second Friedel-Crafts hydroxyalkylation reaction takes 4–16 hours. It should be noted that the time for the second Friedel-Crafts hydroxyalkylation reaction refers to the reaction time after the addition of the second catalyst.

[0083] In step 2), 2-3 mL of the third solvent is added for every 2-3 mmol of haloquinine salt; 2-3 mL of the second catalyst is added accordingly. The third solvent is dichloromethane, and the second catalyst is composed of trifluoromethanesulfonic anhydride and trifluoroacetic acid in a volume ratio of (8-10):1.

[0084] In step 2), the second alkaline solution is a 1-2M NaOH solution. The haloquinine salt is a bromoquinine salt.

[0085] Step 2) involves the following steps to prepare the haloquinine salt: dissolving a 1,n-dihaloalkyl hydrocarbon in a fourth solvent 1 to obtain a 1,n-dihaloalkyl hydrocarbon solution; dissolving a 3-quinine cyclic ketone in a fourth solvent 2 to obtain a 3-quinine cyclic ketone solution; then adding the 1,n-dihaloalkyl hydrocarbon solution dropwise to the 3-quinine cyclic ketone solution at 30–60°C; stirring the reaction for 24–72 hours; and washing and drying after the reaction to obtain the haloquinine salt. A precipitate is formed during the stirring reaction, and the precipitate is washed with acetone and ethyl acetate.

[0086] In step 2), the molar ratio of 1,n-dihaloalkyl hydrocarbon to 3-quinine cycloketone is (25-30):1.

[0087] In step 2), 25-30 mL of fourth solvent 1 is added for every 300-350 mmol of 1,n-dihaloalkyl hydrocarbon; and 10-15 mL of fourth solvent 2 is added for every 10-15 mmol of 3-quinine cycloone.

[0088] In step 2), both fourth solvent 1 and fourth solvent 2 are acetone.

[0089] In step 2), 3-quininecycloketone is obtained by desalting and acidifying 3-quininecycloketone hydrochloride. Specifically, 3-quininecycloketone hydrochloride and anhydrous sodium carbonate are ultrasonicated in water for 5-10 minutes, then extracted with dichloromethane. The extract is then rotary evaporated at 35-40°C to obtain desalted and acidified 3-quininecycloketone.

[0090] In step 2), the molar ratio of 3-quinine cyclic ketone hydrochloride to anhydrous sodium carbonate is 1-2:1-2; 100-150 mL of water is added for every 0.02-0.05 mol of 3-quinine cyclic ketone hydrochloride.

[0091] In step 2), the halide of the side chain is selected from one of the compounds with the structure shown in Formula I and the compounds with the structure shown in Formula II:

[0092]

[0093] In step 2), the compound with the structure shown in Formula I is prepared by a second Friedel-Crafts hydroxyalkylation reaction of biphenyl, bromoquinine salt, and a second catalyst in a third solvent at 0–25 °C; the compound with the structure shown in Formula II is prepared by a second Friedel-Crafts hydroxyalkylation reaction of dibenzo-18-crown ether-6, bromoquinine salt, and a second catalyst in a third solvent at 0–25 °C.

[0094] In step 2), the molar ratio of biphenyl to bromoquinine salt is (5-6):(2-3); the molar ratio of dibenzo-18-crown ether-6 to bromoquinine salt is (5-6):(2-3).

[0095] The embodiments of the present invention will be further described below with reference to specific examples. Unless otherwise specified, the chemical reagents involved in the following examples are all commercially available conventional products.

[0096] I. Specific Examples of the Aromatic Quinine-Aromatic Copolymer with Side Chain Functionalized by the Invention and its Preparation Method Example 1

[0097] The preparation method of the aromatic quinine-aromatic copolymer PBQIS-BQA with aromatic quinine-onium side chain functionalization in this embodiment is as follows:

[0098] 1) Synthesis of PBQIS

[0099] PBQIS polymer was synthesized using a superacid Friedel-Crafts catalytic method: A CH2Cl2 solution of biphenyl (10.0 mmol) and a CH2Cl2 solution of 3-quinine cycloketone hydrochloride (5.00 mmol) (total CH2Cl2 5 mL) were dissolved by stirring at 0 °C. Then, 7 mL of trifluoromethanesulfonic acid (TFSA) and trifluoroacetic acid (TFA) (volume ratio 8:1) were added to the above solution to promote the reaction. After 24 hours, indigo (5.50 mmol), CH2Cl2 (2 mL), and TFSA (2 mL) were added to the reaction system. The reaction was continued for 8 hours. When the polymer solution became extremely viscous and mechanical stirring became difficult, the blue-black viscous solution was poured into a 1.0 M Na2CO3 solution and stirred for 10 h to obtain a fibrous polymer. The polymer was then magnetically stirred overnight to remove excess acid catalyst. Finally, the solution was filtered and vacuum dried at 60 °C for 24 hours to obtain the PBQIS polymer.

[0100] 2) Synthesis of BQA

[0101] Treatment of 1,3-quininecycloketone hydrochloride: 0.031 mol of 1,3-quininecycloketone hydrochloride and 0.031 mol of anhydrous sodium carbonate were added to 100 mL of deionized water and sonicated for 5 minutes until completely dissolved. The solution was then extracted three times with dichloromethane using a separatory funnel. The extracts were rotary evaporated at 35 °C to obtain dehydrochlorinated 3-quininecycloketone (easily oxidized, store in a sealed container under cold conditions).

[0102] Synthesis of bromoquinine salt (QA): First, 1,6-dibromohexane (315.6 mmol) and acetone (25 mL) were mixed thoroughly in a beaker to obtain a 1,6-dibromohexane solution. Next, 12 mmol of 3-quinine cyclohexane (excluding hydrochloric acid) was added to 10 mL of acetone. The mixture was heated and stirred at 35 °C until completely dissolved. Then, using a constant pressure funnel, the previously prepared 1,6-dibromohexane solution was slowly added dropwise to the quinine ketone solution, and the reaction was continuously stirred for 24 hours. During the reaction, the reactants changed from a colorless, transparent solution to a white solution and a precipitate formed. After the reaction was complete, the precipitate was washed several times with acetone and ethyl acetate, and finally dried in a vacuum drying oven at 60 °C for 12 hours to obtain the target product QA.

[0103] Synthesis of BQA: BQA was synthesized via a Friedel-Crafts reaction: 5.68 mmol of biphenyl and 2.27 mmol of bromoquinone salt were added to 2 mL of CH₂Cl₂ and stirred thoroughly at 0 °C until dissolved. Then, 2 mL of trifluoromethanesulfonic acid (TFSA) and trifluoroacetic acid (TFA) (volume ratio 8:1) were added to the solution, and the reaction was carried out at 0 °C for 12 hours. After the reaction was complete, the reactants were poured into a chilled 1 M NaOH solution to precipitate the polymer, and the mixture was magnetically stirred overnight to remove excess acid catalyst. Finally, the mixture was filtered and dried in a vacuum oven at 60 °C to obtain BQA.

[0104] 3) Synthesis of PBQIS-BQA

[0105] PBQIS-BQA polymer was synthesized using the Menxiujin reaction: BQA (0.290 g) and PBQIS (0.320 g) were added to a 10 mL mixture of dimethyl sulfoxide (DMSO) and N-methylpyrrolidone (NMP) (volume ratio 1:0.5), and the reaction was carried out at 60 °C. After 24 hours, excess CH3I (0.300 mL) was added, and the reaction was continued for another 24 hours in the dark. After the reaction was completed, the reaction solution was poured into ethyl acetate to precipitate the crude product, which was then washed several times with deionized water and anhydrous ethanol. Finally, the product was filtered and dried in a vacuum oven at 60 °C to obtain an orange-yellow solid, named […].

[0106] PBQIS-BQA.

[0107] The reaction formulas for the synthesis of PBQIS in step 1) and the synthesis of PBQIS-BQA in step 3) are as follows:

[0108]

[0109] It should be noted that * indicates the location of the repeating unit connection.

[0110] The PBQIS-BQA obtained in this embodiment is the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization provided by the present invention.

[0111] Example 2

[0112] The preparation method of the aromatic quinine-aromatic copolymer PBQIS-DBCQ with the aromatic quinine-onium side chain functionalized in this embodiment is as follows:

[0113] 1) Synthesis of PBQIS: Performed according to step 1) of Example 1.

[0114] 2) Synthesis of DBCQ

[0115] The treatment of 1,3-quinine cyclic ketone hydrochloride and the synthesis of bromoquinine salt (QA) were carried out in step 2) of Example 1.

[0116] Synthesis of DBCQ: BQA was synthesized via a Friedel-Crafts reaction: Dibenzo-18-crown ether-6 (5.68 mmol) and bromoquinine salt (2.27 mmol) were added to 2 mL of CH₂Cl₂ and dissolved by stirring at 0 °C. Then, 2 mL of TFSA and TFA (TFSA to TFA volume ratio 10:1) were added to the solution, and the reaction was carried out at this temperature for 12 hours. After the reaction was complete, the reactants were poured into a chilled 1 M NaOH solution to precipitate the polymer, and the solution was magnetically stirred overnight to remove excess acid catalyst. Finally, the mixture was filtered and dried in a vacuum oven at 60 °C to obtain DBCQ.

[0117] 3) Synthesis of PBQIS-DBCQ

[0118] PBQIS-BQA polymer was synthesized using the Menxiujin reaction: 0.600 g of DBCQ and 0.320 g of PBQIS were added to 10 mL of a mixed solution of DMSO and NMP (DMSO to NMP volume ratio 1:2) and reacted at 60 °C. After 24 hours, excess CH3I (0.300 mL) was added, and the reaction was continued for another 24 hours in the dark. After the reaction was complete, the reaction solution was poured into ethyl acetate to precipitate the crude product, which was then washed several times with deionized water and anhydrous ethanol. Finally, the product was filtered and dried in a vacuum drying oven at 60 °C to obtain an orange-yellow solid, named PBQIS-DBCQ.

[0119] The reaction formulas for the synthesis of PBQIS in step 1) and the synthesis of PBQIS-DBCQ in step 3) are as follows:

[0120]

[0121] The PBQIS-DBCQ obtained in this embodiment is the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization provided by the present invention.

[0122] Example 3

[0123] The preparation method of the aromatic quinine-aromatic copolymer PBPA-DBCQ with side chain functionalization in this embodiment is as follows:

[0124] 1) Synthesis of PBPA: PBPA polymer was synthesized using a superacid Friedel-Crafts catalytic method. A total of 5 mL of CH2Cl2 solution containing 10.0 mmol of biphenyl and 5.00 mmol of 3-quinine cyclohexane hydrochloride was dissolved by stirring at 0°C. Then, 7 mL of trifluoromethanesulfonic acid (TFSA) and trifluoroacetic acid (TFA) (TFSA to TFA volume ratio 10:1) were added to the above solution to promote the reaction. After 24 hours, 5.50 mmol of pyruvic acid, 2 mL of CH2Cl2, and 2 mL of TFSA were added to the reaction system. The reaction was allowed to proceed for 8 hours. When the polymer solution became extremely viscous and mechanical stirring became difficult, the blue-black viscous solution was poured into a 1.0 M Na2CO3 solution to precipitate, yielding a fibrous polymer. The polymer was then magnetically stirred overnight to remove excess acid catalyst. Finally, the solution was filtered and vacuum dried at 60°C for 24 hours to obtain the PBPA polymer.

[0125] 2) Synthesis of PBPA-DBCQ

[0126] PBPA-DBCQ polymer was synthesized using the Menxiujin reaction: 0.600 g of DBCQ and 0.320 g of PBPA were added to 10 mL of a mixed solution of DMSO and NMP (DMSO to NMP volume ratio 1:0.5) and reacted at 60 °C. After 24 hours, excess CH3I (0.300 mL) was added, and the reaction was continued for another 24 hours in the dark. After the reaction was complete, the reaction solution was poured into ethyl acetate to precipitate the crude product, which was then washed several times with deionized water and anhydrous ethanol. Finally, the product was filtered and dried in a vacuum drying oven at 60 °C to obtain an orange-yellow solid, named PBPA-DBCQ.

[0127] The reaction formulas for the synthesis of PBPA in step 1) and the synthesis of PBPA-DBCQ in step 2) are as follows:

[0128]

[0129] The PBPA-DBCQ prepared in this embodiment is the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization provided by the present invention.

[0130] Example 4

[0131] The preparation method of the aromatic quinine-aromatic copolymer PBIM-DBCQ with aromatic quinine-onium side chain functionalization in this embodiment is as follows:

[0132] 1) Synthesis of PBIM: PBIM polymer was synthesized using a superacid Friedel-Crafts catalytic method. A total of 5 mL of CH2Cl2 solution containing 10.0 mmol of biphenyl and 5.00 mmol of 3-quinine cyclohexane hydrochloride was dissolved by stirring at 0°C. Then, 7 mL of trifluoromethanesulfonic acid (TFSA) and trifluoroacetic acid (TFA) (TFSA to TFA volume ratio 9:1) were added to the above solution to promote the reaction. After 24 hours, 5.50 mmol of imidazole-2-carboxaldehyde, 2 mL of CH2Cl2, and 2 mL of TFSA were added to the reaction system. The reaction was allowed to proceed for 8 hours. When the polymer solution became extremely viscous and mechanical stirring became difficult, the blue-black viscous solution was poured into a 1.0 M Na2CO3 solution to precipitate, yielding a fibrous polymer. The polymer was then magnetically stirred overnight to remove excess acid catalyst. Finally, the solution was filtered and vacuum dried at 60°C for 24 hours to obtain the PBIM polymer.

[0133] 2) Synthesis of PBIM-DBCQ

[0134] PBIM-BQA polymer was synthesized using the Menxiujin reaction: 0.600 g of DBCQ and 0.320 g of PBIM were added to 10 mL of a mixed solution of DMSO and NMP (DMSO to NMP volume ratio 1:2) and reacted at 60 °C. After 24 hours, excess CH3I (0.300 mL) was added, and the reaction was continued for another 24 hours in the dark. After the reaction was complete, the reaction solution was poured into ethyl acetate to precipitate the crude product, which was then washed several times with deionized water and anhydrous ethanol. Finally, the product was filtered and dried in a vacuum drying oven at 60 °C to obtain an orange-yellow solid, named PBIM-DBCQ.

[0135] The reaction formulas for the synthesis of PBIM in step 1) and the synthesis of PBIM-DBCQ in step 2) are as follows:

[0136]

[0137] The PBIM-DBCQ prepared in this embodiment is the quinine-aromatic copolymer with aromatic quinine-onium side chain functionalization provided by the present invention.

[0138] Example 5

[0139] The preparation method of the aromatic quinine-aromatic copolymer PBPy-DBCQ with aromatic quinine-onium side chain functionalization in this embodiment is as follows:

[0140] 1) Synthesis of PBPy: PBPy polymer was synthesized using a superacid Friedel-Crafts catalytic method: A CH2Cl2 solution of biphenyl (10.0 mmol) and a CH2Cl2 solution of 3-quinine cycloketone hydrochloride (5.00 mmol) (total CH2Cl2 5 mL) were dissolved by stirring at 0 °C. Then, 7 mL of trifluoromethanesulfonic acid (TFSA) and trifluoroacetic acid (TFA) (TFSA to TFA volume ratio 8:1) were added to the above solution to promote the reaction. After 24 hours, pyridine-4-carboxaldehyde (5.50 mmol), CH2Cl2 (2 mL), and TFSA (2 mL) were added to the reaction system. The reaction was allowed to proceed for 8 hours. When the polymer solution became extremely viscous and mechanical stirring became difficult, the blue-black viscous solution was poured into a 1.0 M Na2CO3 solution to precipitate, yielding a fibrous polymer. The polymer was then magnetically stirred overnight to remove excess acid catalyst. Finally, the solution was filtered and vacuum dried at 60 °C for 24 hours to obtain the PBIM polymer.

[0141] 2) Synthesis of PBPy-DBCQ

[0142] PBPy-BQA polymer was synthesized using the Menxiujin reaction: 0.600 g of DBCQ and 0.320 g of PBPy were added to 10 mL of a mixed solution of DMSO and NMP (DMSO to NMP volume ratio 1:1) and reacted at 60 °C. After 24 hours, excess CH3I (0.300 mL) was added, and the reaction was continued for another 24 hours in the dark. After the reaction was complete, the reaction solution was poured into ethyl acetate to precipitate the crude product, which was then washed several times with deionized water and anhydrous ethanol. Finally, the product was filtered and dried in a vacuum drying oven at 60 °C to obtain an orange-yellow solid, named PBPy-DBCQ.

[0143] The reaction formulas for the synthesis of PBPy in step 1) and the synthesis of PBPy-DBCQ in step 2) are as follows:

[0144]

[0145] The PBPy-DBCQ prepared in this embodiment is the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization provided by the present invention.

[0146] II. Experimental Examples

[0147] Preparation of ion exchange membranes: A series of membranes (AEMs) were prepared using a solution casting method: First, 2.00 g of the aromatic quinine-aromatic copolymer functionalized with the side chain of any one of Examples 1-4 was dissolved in 100 mL of DMSO to form a 2 wt% polymer solution. Next, the polymer solution was filtered using a 0.24 μm filter membrane to remove undissolved particles. Subsequently, the homogeneous polymer solution was cast onto a transparent glass substrate and dried at 60 °C for 24 hours. After the solvent had completely evaporated, the formed membrane was peeled off from the glass substrate and immersed in a 1.0 M KOH solution at 80 °C for at least 24 hours to allow the membrane to precipitate. - With OH - Fully exchange. Finally, transfer these OH groups... - The membrane was washed several times with deionized water and stored in N2-saturated deionized water for further use.

[0148] 1) 1 H NMR spectrum

[0149] The chemical structure of the copolymer is obtained through 1 Characterized by 1H NMR. PBQIS 1 H NMR spectrum as follows Figure 1 As shown, from Figure 1 It can be seen that the signal peaks at chemical shifts of 6.68–7.60 ppm correspond to protons on biphenyl. The weak signals at chemical shifts of 6.71–6.99 ppm correspond to aromatic ring protons (c and d) on indigo. These results indicate the successful synthesis of the PBQIS copolymer.

[0150] DBCQ 1 H NMR spectrum as follows Figure 2 As shown. Figure 2 It can be seen that the signals at 1.12–2.05 ppm, 2.99–3.57 ppm, and 4.27 ppm correspond to methylene and methine protons on the quinine ring and the hexane long chain, respectively. The characteristic peaks at chemical shifts of 6.62–7.25 ppm represent aromatic ring protons (c, d, and e) on the crown ether. The characteristic peaks at chemical shifts of 3.57–4.41 ppm represent methylene protons (a and b) on the crown ether ring. These structures indicate the successful synthesis of the DBCQ side chain.

[0151] PBQIS-BQA and PBQIS-DBCQ 1 The H NMR spectra are as follows: Figure 3 and 4 As shown, where Figure 3 This is a characterization diagram of PBQIS-BQA. Figure 4 This is a characterization diagram of PBQIS-DBCQ. Figure 3It can be seen that the weak signals in the chemical shift range of 6.65-7.71 ppm are biphenyl and indigo aromatic ring protons (ad). Figure 4 It can be seen that the characteristic peaks at chemical shifts of 6.76–7.66 ppm correspond to protons (af) on biphenyl, indigo, and crown ethers. The signals at 1.07–2.05 ppm, 2.94–3.57 ppm, and 4.40 ppm in both figures represent methyl, methylene, and methine protons on the quinine ring and hexane. These structures demonstrate the successful preparation of the PBQIS-BQA and PBQIS-DBCQ polymers.

[0152] 2) Molecular weight

[0153] The molecular weight of the PBQIS copolymer was determined by gel permeation chromatography, and the results are shown in Table 1 and 2. Figure 5 As shown, the results indicate that the weight-average molecular weight of the copolymer is around 49 kDa, and the polydispersity index (PDI) is 1.36. High Mw and narrow PDI are beneficial to enhancing film-forming ability and improving the mechanical properties of the film.

[0154] Table 1. Molecular weight of PBQIS series copolymers

[0155] Sample Name Number-average molecular weight Mn (kDa) Weight-average molecular weight Mw (kDa) PDI PBQIS 36.17 49.33 1.36

[0156] 3) Ion exchange capacity (IEC), water absorption rate (WU), swelling degree (SR), and water contact angle (WCA)

[0157] The ion exchange capacity (IEC) of all AEMs was obtained by titration. Test results showed that the IEC values ​​of the PBQIS series copolymers ranged from 2.15 to 2.17 mmol·g. -1 Of which PBQIS-BQA was 2.15 mmol·g. -1 The PBQIS-DBCQ value was 2.17 mmol·g. -1 The PBPA-DBCQ value was 2.03 mmol·g. -1 The PBIM-DBCQ value was 2.33 mmol·g. -1 The PBPy-DBCQ value was 2.52 mmol·g. -1 .

[0158] The water absorption (WU) and swelling degree (SR) test results of PBQIS series membranes are as follows: Figure 6 As shown, where Figure 6 (a) and (b) show the swelling ratio and water uptake of the PBQIS series membranes measured at different temperatures, respectively. Figure 6It can be seen that the changes in water absorption and swelling degree also correspond to IEC, with PBQIS-BQA having the lowest WU at 8.69% and SR at 3.43%. Because the crown ether group in PBQIS-QBCQ contains oxygen atoms, it can form weak hydrogen bonds with water, resulting in a higher WU value than PBQIS-BQA. However, both PBQIS-QBCQ and PBQIS-BQA membranes exhibit very low water absorption and swelling, which is because they can form π-π interactions, enhancing the degree of physical cross-linking and thus reducing the membrane's water absorption and swelling degree.

[0159] Figure 7 The water contact angle of the ion exchange membrane is shown in the figure. It can be seen that the WCA gradually decreases with the increase of the volume of the added side chain, with a minimum of 66.59°. This indicates that the addition of long side chains improves the surface hydrophilicity of PBQIS-QBCQ and PBQIS-BQA membranes.

[0160] 4) Mechanical properties

[0161] The tensile strength and elongation at break of the prepared AEMs were obtained under different environmental humidity conditions. The test results for tensile strength and elongation at break are shown below. Figure 8 As shown, where Figure 8 (a) shows the stress-strain curves of the PBQIS series membranes in a dry state. Figure 8 (b) shows the stress-strain curves of the PBQIS series membranes under wet conditions. Figure 8 (a) It can be seen that PBQIS-DBCQ exhibits the highest tensile strength of 52.85 MPa and elongation at break of 13.64%, indicating that the addition of crown ether enhances the physical crosslinking effect and improves the mechanical properties of the PBQIS-DBCQ membrane. To evaluate the suitability of the prepared AEMs, the tensile strength and elongation at break were measured under a fully wetted condition. Figure 8 (b) The results showed that the mechanical properties of AEMs decreased when fully wetted due to the plasticizing effect of water. The tensile strength of all wetted films ranged from 31.76 to 39.26 MPa, and the elongation at break ranged from 15.58% to 22.96%, indicating that they have very good mechanical properties.

[0162] Figure 9 These are digital photos of the PBQIS series membranes. As can be seen from the photos, the PBQIS-DBCQ and PBQIS-BQA membranes retain their good shape even after being folded and unfolded, indicating their excellent mechanical properties.

[0163] 5) Thermal stability

[0164] The thermal stability of AEMs is crucial to ensuring their performance in water electrolysis. This study investigated the thermal stability of AEMs in a N2 atmosphere at 10 °C·min. -1The thermal stability was assessed by measuring the thermogravimetric changes from room temperature to 700°C at the rate of heating. The thermogravimetric change curve is shown below. Figure 10 As shown, the PBQIS-QBCQ and PBQIS-BQA polymers exhibit very similar thermogravimetric trends due to the introduction of similar side-chain structures. Mass loss below 170℃ is attributed to the evaporation of residual water and solvent within the membrane. At 300℃, side-chain degradation begins, leading to significant weight loss in the AEMs. At 500℃, the polymer backbone begins to degrade. Simultaneously, the quaternary ammonium bonds connecting the side chains and backbone are prone to decomposition upon heating, resulting in an earlier second-stage thermal decomposition temperature. Even so, the degradation temperatures of all AEMs are significantly higher than the operating temperature of AEMWE, thus the prepared AEMs exhibit remarkable thermal stability, meeting the temperature requirements for long-term water electrolysis operation.

[0165] 6) Ion conductivity

[0166] OH of all AEMs - The conductivity was measured in an aqueous environment at 20-80℃ using a four-probe method. The hydroxide ion conductivity test results for the PBQIS series membranes are as follows: Figure 11 As shown, the OH groups of all membranes - The conductivity increases with increasing temperature, indicating that ionic conductivity is thermodynamically driven. The hydroxide ion conductivity of PBQIS-DBCQ at 80 °C is 88.50 mS / cm. -1 PBQIS-BQA has a low hydroxide ion conductivity of 76.18 mS·cm. -1 The Cl of AEMs was also tested. - Conductivity was used to verify its ion transport capability. Figure 12 ), Cl of all membranes - Conduction Laws and OH - The conductivity test results were consistent. Furthermore, the hydroxide ion conductivity of DBCQ side-chain functionalized copolymers, including the PBPA-DBCQ, PBIM-DBCQ, and PBPy-DBCQ series ion exchange membranes, was as follows: Figure 13 The hydroxide ion conductivity at 80℃ was 90.21, 105.32, and 121.15 mS / cm, respectively. -1 .

[0167] 7) Alkali resistance and oxidation stability

[0168] The PBQIS-BQA and PBQISP-DBCQ membranes were prepared by immersing them in 2.0M NaOH at 80℃, and the OH content was tested periodically. - Their alkali stability was evaluated using conductivity and IEC standards. The alkali stability test results are as follows: Figure 14As shown, AEMs in 2.0M NaOH solution at 80℃ have OH... - Residual conductivity curve. Figure 14 The results show that the OH values ​​of PBQIS-BQA and PBQISP-DBCQ are... - The conductivity gradually decreased with increasing immersion time in the alkaline solution. After immersion in 2.0M NaOH at 80℃ for 3000 hours, the PBQIS-BQA membrane retained its original OH content. - The conductivity is 78.47%, slightly higher than that of the PBQIS-DBCQ membrane (77.99%).

[0169] By immersing PBQIS-BQA and PBQISP-DBCQ membranes in Fenton's reagent (30wt% H2O2 + 3ppm Fe) at 80°C 2 + In this study, the oxidative stability of the membranes was evaluated by measuring their weight at different times. After 140 hours of testing, PBQIS-BQA retained 98.25% of its original weight, and PBQIS-DBCQ retained 98.01% of its original weight. Furthermore, both PBQIS-BQA and PBQIS-DBCQ membranes maintained their integrity after the 140-hour test. This indicates that the presence of biphenyl and crown ethers in the polymer side chains does not affect their oxidative stability.

[0170] 8) Water electrolysis performance

[0171] PBQIS-BQA and PBQISP-DBCQ membranes were selected and membrane electrode assemblies (MEAs) were prepared using the catalyst-coated substrate (CCS) method. Commercially available IrO2 (20 wt%) was used as the anode and Pt / C (70 wt%) as the cathode to construct the AEMWE. A 1.0 M KOH solution was used as the electrolyte, the test temperature was 60 °C, and the electrolyte flow rate was 20 mL / min. Furthermore, electrochemical impedance spectroscopy (EIS) was performed on the electrolyzers assembled with PBQIS-BQA and PBQISP-DBCQ membranes to investigate the differences in AEMWE performance. Nyquist plots of the EIS spectra were fitted using equivalent circuits. Figure 15 The polarization curves of the PBQIS series membranes are shown, and the EIS curves of AEMs at 1.8V are shown.

[0172] Figure 15 The results show that the AEMWE performance of PBQIS-BQA is 0.16 A·cm. -2 @1.8V and 0.43A·cm -2 @2.0V, in comparison, the PBQIS-DBCQ showed an AEMWE performance of 0.07 A·cm. -2 @1.8V and 0.1595A·cm -2@2.0V.

[0173] Figure 16 The graph shows the ohmic resistance (Rel) test results of an electrolyzer assembled with PBQIS series membranes, which is related to the membrane, current collector, catalyst layer, contact surface, and electrolyte solution. The Rel value of the electrolyzer assembled with PBQIS-BQA is 0.7135 Ω·cm. 2 The Rel value of the PBQISP-DBCQ electrolyzer is the smallest among them, at 0.5335 Ω·cm. 2 .

[0174] The AEMWE durability of PBQIS-BQA and PBQISP-DBCQ films was evaluated by constant current testing at 60°C. The two-electrode stability curves of the AEMs at 60°C and 200mA current are shown below. Figure 17 As shown, Figure 17 It can be seen that the battery voltage of PBQIS-BQA gradually increases from 2.44V to 2.48V, with a degradation rate of 0.370mV·h. -1 The PBQISP-DBCQ's battery voltage increased from 2.46V to 2.54V, but its degradation rate was relatively high, at 0.66mV·h. -1 Overall, the prepared AEMs exhibited excellent current-constant stability. This demonstrates that the cyclic structure of quinine can restrict the free rotation of molecules, keeping the molecular conformation relatively fixed and preventing deformation and reactions. Furthermore, this rigid structure can resist the influence of acids and bases in the external environment, reducing the possibility of molecular degradation or other chemical reactions.

[0175] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An arene quaternary phosphonium side chain functionalized quinine-arene copolymer characterized in that, The aromatic quinine-aromatic copolymer with side-chain functionalization of quinine-onium has the following repeating units: The structural formula of the side chain is as follows: Where Ar1 is the first phenyl structural unit, Ar2 is the second phenyl structural unit; R1 is the multifunctional structural unit, R2 is the third phenyl structural unit; x1+y+x2=100%, x1, y≠0, n is selected from integers from 1 to 10, and Z is 0 or 1; when Z=0, the multifunctional structural unit includes one or more of fluoromethylbenzene, haloalkyl, alkyl, fatty acid, nitrobenzene, and benzonitrile; when Z=1, the multifunctional structural unit includes one or two of tertiary amine groups and secondary amine groups.

2. The quinine-aromatic copolymer with aromatic quinine onion side chain functionalization as described in claim 1, characterized in that, selected from one of the following structural formulae:

3. The quinine-arene copolymer functionalized with an arene quaternary phosphonium side chain according to claim 1 or 2, characterized in that, Ar1 and Ar2 are each independently selected from at least one of the following structures: The R2 is selected from at least one of the third phenyl structural units of the following structures:

4. The quinine-aromatic copolymer with aromatic quinine onion side chain functionalization as described in claim 1, characterized in that, The aromatic quinine-aromatic copolymer with side-chain functionalization of aromatic quinine onion has one of the following repeating units:

5. A method for preparing a quinine-aromatic copolymer with a quinine-onium side chain functionalized according to any one of claims 1-4, characterized in that, Includes the following steps: According to the structure of the quinine-aromatic copolymer with side chain functionalization, the first phenyl structural unit Ar1, the second phenyl structural unit Ar2, 3-quinine cyclic ketone hydrochloride, the multifunctional structural unit R1 containing a ketone or aldehyde group, and the first catalyst are subjected to a first Friedel-Crafts hydroxyalkylation reaction in a first solvent to obtain a long-chain copolymer; the long-chain copolymer, the side chain side halide, and iodomethane are subjected to a Mensøe-Gold reaction in a second solvent to obtain the quinine-aromatic copolymer with side chain functionalization.

6. The method for preparing quinine-aromatic copolymers with aromatic quinine ononium side chains as described in claim 5, characterized in that, The side chain halide is obtained by performing a second Friedel-Crafts hydroxyalkylation reaction on a third solvent with a haloquinine salt, a third phenyl structural unit R2, and a second catalyst; the haloquinine salt is obtained by reacting a 1,n-dihaloalkyl hydrocarbon and a 3-quinine cycloketone in a fourth solvent, wherein n is selected from an integer from 1 to 10, and the number of carbon atoms in the alkyl hydrocarbon is n.

7. The method for preparing the quinine-aromatic copolymer with aromatic quinine onion side chain functionalization as described in claim 6, characterized in that, The haloquinine salt is obtained by adding a 1,n-dihaloalkyl hydrocarbon solution dropwise to a 3-quinine cycloketone solution and reacting at 30–60°C for 24–72 h; the temperature of the second Friedel-Crafts hydroxyalkylation reaction is 0–25°C, and the time of the second Friedel-Crafts hydroxyalkylation reaction is 4–16 h.

8. The method for preparing quinine-aromatic copolymers with aromatic quinine ononium side chains as described in claim 6, characterized in that, The molar ratio of haloquinine salt to the third phenyl structural unit R2 is (2-3):(5-6); the molar ratio of 1,n-dihaloalkyl hydrocarbon to 3-quinine cycloketone is (25-30):

1.

9. The method for preparing quinine-aromatic copolymers with aromatic quinine ononium side chains as described in claim 5, characterized in that, The molar ratio of the first phenyl structural unit Ar1, the second phenyl structural unit Ar2, 3-quinine cycloketone hydrochloride, and the multifunctional structural unit containing ketone or aldehyde groups is (1-1.1):(1-1.1):(1-1.5):(1-1.2); the mass ratio of the long-chain copolymer and the side chain halide is (0.3-0.4):(0.2-0.6).

10. The method for preparing the quinine-aromatic copolymer with aromatic quinine ononium side chain functionalization as described in claim 5, characterized in that, The multifunctional structural unit containing a ketone or aldehyde group is selected from one or more compounds containing the following structural formulas: Where m is selected from integers from 1 to 5.

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