Addition polynorbornene-based anion exchange ionomer and method of making and use thereof

Abstract

The application discloses an addition polynorbornene-based anion exchange ionomer, a preparation method and application thereof, and belongs to the technical field of ion exchange membranes. The application can improve the dispersibility of a raw material by using simple water as a solvent and adding water-soluble amine in water while completing the quaternization of the water-insoluble polymer raw material, and can ensure that the hydrophilic polymer after quaternization can be dissolved in an aqueous solution containing amine. The excess amine raw material and solvent water can be easily removed through a reduced pressure distillation treatment. The quaternization degree of the addition polynorbornene-based AEI in the form of a quaternary ammonium salt synthesized by the application is more than 90%, and the addition polynorbornene-based AEI is soluble in a low-boiling-point solvent, so that the solvent casting method for preparing a membrane electrode can be ensured. The synthesis method of the addition polynorbornene-based anion exchange ionomer is simple and easy to operate, does not use an organic solvent, and does not need complex sedimentation and centrifugation operations, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and conversion technology, and relates to an addition polynorbornen-based anion exchange ionomer, its preparation method and application, specifically an addition polynorbornen-based anion exchange ionomer and its large-scale aqueous phase preparation method and application. Background Technology

[0002] Hydrogen energy, because it produces only water and no carbon dioxide when burned or used to generate electricity through fuel cells, has become a key vehicle for achieving the global vision of carbon neutrality. The process of producing hydrogen and oxygen by electrolyzing water using renewable electricity is known as "green hydrogen" production. Among the many water electrolysis technologies, anion exchange membrane (AEM) electrolysis for hydrogen production is considered the most promising next-generation large-scale green hydrogen production technology due to its combination of the low-cost material system of alkaline electrolyzers and the high efficiency and rapid response of proton exchange membrane (PEM) electrolyzers.

[0003] Anion exchange membrane electrolysis (AEMWE) and anion exchange membrane fuel cells (AEMFC) utilize non-precious metal catalysts and exhibit rapid cathode reaction kinetics, making them key devices for the efficient production and utilization of hydrogen. The anion exchange membrane (AEM), anion exchange ionomer (AEI), and electrode reaction catalyst are crucial components of AEMFC and AEMWE, significantly impacting their performance and durability. To date, most research has focused on improving the performance of AEMWE and AEMFC based on AEM and electrode reaction catalysts, but research on AEI is lacking. AEI can act as a binder to immobilize catalyst particles on a substrate or AEM and facilitate the conduction of water and OH groups between the catalyst and AEM. - Currently, the main challenges facing AEI (Aromatic Electrode Ingredient) are solubility, aryl group adsorption, and adhesion. The solubility of AEI in low-boiling-point solvents (such as ethanol, methanol, and isopropanol) is crucial to the fabrication process of the membrane electrode, determining its preparation method. The presence of aryl groups in the chemical structure of AEI may lead to catalyst adsorption, thereby reducing catalyst activity and affecting electrode stability. Due to the rinsing effect of circulating water on the electrode during water electrolysis, the adhesive strength of the AEI also plays a vital role in preventing catalyst loss.

[0004] Polynorbornene possesses an all-carbon-hydrogen backbone structure, thus exhibiting excellent thermal and chemical stability; furthermore, its absence of benzene rings makes it a promising AEI material. However, the large-scale preparation of polynorbornene-based AEIs currently faces systemic challenges. This is primarily because polynorbornene itself is a lipophilic hydrophobic polymer. Although quaternization introduces ionic functional groups, resulting in a hydrophilic polymer, the significant difference in solubility between the two makes it difficult to find a solvent that can simultaneously dissolve both the unquaternized and post-quaternized polymers, thus greatly limiting the large-scale preparation of such AEI materials. For example, Kohl et al. (J. Electrochem. Soc. 2020, 167(16), 164514; J. Electrochem. Soc. 2021, 168(2), 024503) sprayed catalyst and AEI particles suspended in solvent onto a substrate. Since the crosslinked AEI is insoluble in the solvent, it can only be dispersed by manual grinding, resulting in uneven adhesion and distribution of AEI on the substrate. In the patent application and literature with application number 202411264129.3 (Adv. Energy Mater. 2023, 13, 2203488), the polymer was slowly dissolved at high temperature using N-methylpyrrolidone (NMP) as a solvent. The final product can be dissolved in NMP solvent. However, since NMP has a very high boiling point and the precipitation and collection of the polymer are difficult, the product can only be collected by centrifugation, resulting in a large waste of solvent and making it impossible to achieve large-scale preparation. The literature (ACS Applied Polymer Materials 2025, 7, 2595-2602) reports the use of tetrahydrofuran (THF) as an organic solvent to dissolve polymers, followed by the addition of an appropriate amount of aqueous solution for quaternization. However, the degree of quaternization using this method is limited, specifically because polymer precipitation occurs as the degree of quaternization increases, preventing the degree of quaternization from exceeding 50%. In view of this, the present invention is proposed. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a scale-up aqueous preparation method for addition polynorbornen-based anion exchange polymers (also known as polynorbornen-based AEI). This invention uses simple water as a solvent and adds a water-soluble amine to the water, thereby improving the dispersibility of the water-insoluble polymer raw material while simultaneously quaternizing it, and ensuring that the quaternized hydrophilic polymer can dissolve in an aqueous solution containing the amine. Excess amine raw material and solvent water can then be easily removed by vacuum distillation. The quaternary ammonium salt form of the addition polynorbornen-based AEI synthesized by this invention has a quaternization degree far greater than 50%, even exceeding 90%. Furthermore, the polynorbornen-based AEI of this invention is soluble in low-boiling-point solvents, thus ensuring that membrane electrodes can be fabricated using solvent casting. The synthesis method of polynorbornen-based AEI of this invention is simple and easy to operate, does not use organic solvents, and does not require complex sedimentation and centrifugation operations, making it suitable for large-scale production.

[0006] The technical solution of the present invention is as follows:

[0007] An ionomer having a structure represented by at least one of formulas (I) to (III):

[0008]

[0009] in:

[0010] R1 is -C 1-10 Alkylene-N + (R5)(R6)(R7)X - X is a halogen;

[0011] R2 is selected from H and C. 1-10 Alkyl, C 1-10 Alkylene-X', C 6-14 Aryl, C 2-10 One of the alkenyl groups; X' is selected from halogens;

[0012] R3 is C 2-10 alkenyl;

[0013] R4 is selected from H and C. 1-10 Alkyl, C 6-14 Aryl, C 2-10 One of the alkenyl groups;

[0014] The ratio of m to n is 1:10 to 10:1, preferably (1 to 8):1;

[0015] R5, R6, and R7 may be the same or different and are independently selected from alkyl chains or cycloalkyl chains, and the total number of carbon atoms of R5, R6, and R7 does not exceed 10; R5, R6, and R7 may also be the same or different and are independently selected from oxygen-containing alkyl ether chains.

[0016] In this invention, R1 is -C 1-10 The alkylene quaternary ammonium salt, i.e., the ionomer is an addition polynorbornene AEI in the form of a quaternary ammonium salt. Additionally, R5, R6, and R7 of the present invention can be selected from oxygen-containing alkyl ether chains, the purpose of which is to ensure the water solubility of the tertiary amine.

[0017] According to the present invention, m and n are selected from 10 to 500, preferably 20 to 300.

[0018] According to the present invention, X is Cl, Br or I.

[0019] According to the present invention, X' is Cl, Br or I.

[0020] According to the present invention, R1 is preferably -C 1-6 Alkylene-N + (R5)(R6)(R7)X - X is a halogen; R5, R6 and R7 are defined as above.

[0021] According to the present invention, the -N + (R5)(R6)(R7)X - It is derived from at least one of trimethylamine, triethylamine, tri-n-propylamine, N-methylpiperidine, N-methyltetrahydropyrrole, N-methylmorpholin, and N-ethylpiperidine.

[0022] According to the present invention, R2 is selected from H and C. 1-6 Alkyl, C 1-6 Alkylene-X', C 6-14 Aryl, C 2-6 One of the alkenyl groups, where X' is selected from halogens; more preferably, it is H.

[0023] According to the present invention, R3 is C 2-6 Alkenyl, more preferably vinyl.

[0024] According to the present invention, R4 is selected from H and C. 1-6 Alkyl, C 6-14 Aryl, C 2-6 One of the alkenyl groups, more preferably H.

[0025] According to the present invention, the ionomer is soluble at room temperature in a mixed solvent consisting of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, dimethyl sulfoxide, and water.

[0026] According to the present invention, the ionomer specifically has at least one of the following structural formulas:

[0027]

[0028] Wherein, the ratio of m to n is 1:10 to 10:1, preferably (1 to 8):1; for example, m and n are selected from integers from 10 to 500, preferably 20 to 300.

[0029] The present invention also provides a method for preparing the above-mentioned ionomer, comprising the following steps: soaking polynorbornene in an aqueous solution of a tertiary amine to carry out a quaternization reaction, thereby obtaining the ionomer.

[0030] According to the present invention, the preparation method specifically includes the following steps: soaking polynorbornene in an aqueous solution of a tertiary amine to carry out a quaternization reaction, and performing vacuum distillation on the reaction solution after the quaternization reaction to remove residual amine and water with low boiling point, thereby obtaining the ionomer.

[0031] According to the present invention, the preparation method further includes the following steps:

[0032] The polynorbornene was soaked in an aqueous solution of a tertiary amine. As the quaternization reaction proceeded, the product gradually dissolved in the aqueous amine solution. The reaction continued until the addition copolymer was completely dissolved to obtain a clear and transparent solution. After the reaction was completed, the low-boiling-point residual amine and water were removed by vacuum distillation to obtain the ionomer.

[0033] According to the present invention, the polynorbornene has a structure shown in at least one of the following formulas (IA) to (IIIA):

[0034]

[0035] in:

[0036] R 1 -C 1-10 Alkylene-X; X is selected from halogens;

[0037] R 2 Selected from H, C 1-10 Alkyl, C 1-10 Alkylene-X', C 6-14 Aryl, C 2-10 One of the alkenyl groups; X' is selected from halogens;

[0038] R 3 C 2-10 alkenyl;

[0039] R 4 Selected from H, C 1-10 Alkyl, C 6-14 Aryl, C 2-10 One of the alkenyl groups;

[0040] The ratio of m to n is 1:10 to 10:1, preferably (1 to 8):1.

[0041] According to the present invention, m and n are selected from 10 to 500, preferably 20 to 300.

[0042] According to the present invention, the tertiary amine is used for quaternization reactions; specifically, the tertiary amine has the structure shown in the following formula:

[0043]

[0044] R5, R6, and R7 may be the same or different and are independently selected from alkyl chains or cycloalkyl chains, and the total number of carbon atoms of R5, R6, and R7 does not exceed 10; R5, R6, and R7 may also be the same or different and are independently selected from oxygen-containing alkyl ether chains.

[0045] According to the present invention, the tertiary amine includes, but is not limited to, one of the following structures: trimethylamine, triethylamine, tri-n-propylamine, N-methylpiperidine, N-methyltetrahydropyrrole, N-methylmorpholinine, and N-ethylpiperidine.

[0046] According to the present invention, R 1 Preferred -C 1-6 Alkylene-X, where X is Cl, Br, or I.

[0047] According to the present invention, R 2 Selected from H, C 1-6 Alkyl, C 1-6 Alkylene-X', C 6-14 Aryl, C 2-6 One of the alkenyl groups, where X' is selected from halogens; more preferably, it is H.

[0048] According to the present invention, R 3 C 2-6 Alkenyl, more preferably vinyl.

[0049] According to the present invention, R 4 Selected from H, C 1-6 Alkyl, C 6-14 Aryl, C 2-6 One of the alkenyl groups, more preferably H.

[0050] As an exemplary embodiment of the present invention, the polynorbornene has one of the following structural formulas:

[0051]

[0052] The ratio of m to n is 1:10 to 10:1; for example, m and n are selected from 10 to 500, preferably 20 to 300.

[0053] According to the present invention, the polynorbornene is an addition-type polynorbornene.

[0054] According to the present invention, the polynorbornene is obtained by copolymerization of monomer 1 and monomer 2.

[0055] Among them, monomer 1 has the structure shown in formula (1);

[0056]

[0057] Monomer 2 has one of the structures shown in equation (2), equation (3) or equation (4):

[0058]

[0059] In equation (1), R 1 -C 1-10 Alkylene-X'; X' is a halogen;

[0060] R 2 Selected from H, C 1-10 Alkyl, C 1-10 Alkylene-X', C 6-14 Aryl, C 2-10 One of the alkenyl groups; X' is a halogen.

[0061] In equation (2), R 3 C 2-10 alkenyl,

[0062] R 4 Selected from H, C 1-10 Alkyl, C 6-14 Aryl, C 2-10 One of the alkenyl groups.

[0063] According to the present invention, X' is Cl, Br or I.

[0064] According to the present invention, R 1 Preferred -C 1-6 Alkylene-X'; X' is a halogen.

[0065] According to the present invention, R 2 Selected from H, C 1-6 Alkyl, C 1-6 Alkylene-X', C 6-14 Aryl, C 2-6 One of the alkenyl groups, where X' is a halogen; more preferably, it is H.

[0066] According to the present invention, R 3 C 2-6 Alkenyl, more preferably vinyl.

[0067] According to the present invention, R 4 Selected from H, C 1-6 Alkyl, C 6-14 Aryl, C 2-6One of the alkenyl groups, more preferably H.

[0068] According to the present invention, the molar ratio of monomer 1 to monomer 2 is 10:1 to 1:10, preferably (1 to 8):1.

[0069] According to the present invention, the tertiary amine includes, but is not limited to, one of the following structures: trimethylamine, triethylamine, tri-n-propylamine, N-methylpiperidine, N-methyltetrahydropyrrole, N-methylmorpholinine, and N-ethylpiperidine.

[0070] According to the present invention, the concentration of the aqueous solution of the tertiary amine is 10-50 wt%, preferably 20-40 wt%, for example 30 wt%.

[0071] According to the present invention, the soaking temperature is 0℃-95℃, preferably room temperature-80℃; the soaking time is 10-96h, preferably 12-96h, and more preferably 24-48h.

[0072] According to the present invention, the method for preparing the polynorbornene includes:

[0073] Monomer 1 and monomer 2 are dissolved in a solvent to prepare a monomer solution. The first catalyst and its auxiliaries are dissolved in a solvent to prepare a catalyst solution. Then, the catalyst solution is added to the monomer solution to carry out a polymerization reaction, thereby preparing the polynorbornene, i.e., addition-type polynorbornene.

[0074] According to the present invention, the first catalyst includes, but is not limited to, a Pd catalyst or a Ni catalyst, such as tris(dibenzylacetone)dipalladium (Pd2(dba)3), palladium acetate (Pd(OAc)2), and bis(triphenylantimony)bis(pentafluorophenyl)nickel (Ni(C6F5)2(SbPh3)2).

[0075] According to the present invention, the auxiliary agent includes at least one of a stabilizer for the first catalyst (such as tricyclohexylphosphine (PCy3)) and a co-catalyst (such as lithium tetra(pentafluorophenyl)borate-ethyl ether complex (LiFABA) or sodium tetra(3,5-di(trifluoromethyl)phenyl)borate (NaBARF)).

[0076] Preferably, in the preparation method of polynorbornene, the first catalyst system used is Pd2(dba)3, PCy3 and LiFABA, wherein the molar ratio of Pd2(dba)3, PCy3 and LiFABA is 1:4:4.

[0077] According to the present invention, the molar ratio of monomer 1 to monomer 2 is 10:1 to 1:10, preferably (1 to 8):1.

[0078] According to the present invention, in the method for preparing polynorbornene, the solvent is toluene, wherein the total molar number of monomer 1 and monomer 2 to the volume ratio of solvent is 0.1-2 mmol / ml, more preferably 0.4-0.6 mmol / ml.

[0079] Preferably, the ratio of the total molar number of the first catalyst to the total molar number of monomers 1 and 2 to the total molar number of the catalyst is 1:20 to 1:1000, more preferably 1:40 to 1:600.

[0080] Preferably, the polymerization reaction time of the present invention is 10h to 48h, more preferably 12h to 40h.

[0081] Preferably, the polymerization reaction temperature of the present invention is 20-60°C, more preferably 20-30°C.

[0082] Preferably, the polymerization reaction described in this invention is carried out under anhydrous and oxygen-free conditions.

[0083] The present invention also provides the application of the above-mentioned ionomers in the preparation of membrane electrodes in the fields of fuel cells and water electrolysis.

[0084] The present invention also provides a catalytic slurry comprising the above-mentioned ionomer.

[0085] According to the present invention, the catalytic slurry further includes a catalyst and a solvent.

[0086] According to the present invention, the mass ratio of the catalyst to the ionomer is 20:1 to 1:1, preferably 15:1 to 5:1.

[0087] According to the present invention, the concentration of the catalyst is 0.1 wt% to 5 wt%, preferably 0.5 wt% to 1 wt%.

[0088] According to the present invention, the catalyst comprises at least one selected from NiFe, NiFeCo, Pt / C, PtRu / C, Pt, Pd, Ir, IrO2 and Ru.

[0089] The present invention also provides a membrane electrode prepared from the above-mentioned catalytic slurry.

[0090] According to the present invention, the membrane electrode is prepared by spraying the above-mentioned catalytic slurry onto a gas diffusion layer and combining it with an ion exchange membrane. The total loading of the catalyst and ionomer is determined by weighing after spraying. For example, the total loading of the catalyst and ionomer is 0.5–5 mg / cm³. 2 Optimized to 1-3 mg / cm³ 2 .

[0091] According to the present invention, the gas diffusion layer comprises at least one of carbon paper, carbon felt, porous stainless steel mesh, nickel mesh, nickel felt, and nickel foam.

[0092] According to the present invention, the ion exchange membrane is a membrane material that can selectively transport ions.

[0093] The present invention also provides an electrolytic cell comprising the above-described membrane electrode.

[0094] The beneficial effects of this invention are:

[0095] (1) The present invention provides an ionomer with a quaternization degree greater than 50% or even higher than 90%, which is a novel addition polynorbornene AEI in the form of a quaternary ammonium salt. It is soluble in low-boiling solvents (such as methanol and dimethyl sulfoxide), thereby ensuring that membrane electrodes can be prepared by solvent casting.

[0096] (2) The present invention provides a method for large-scale preparation of the ionomer. The synthesis method is simple and easy to operate, does not use toxic reagents and solvents, and is suitable for large-scale production of polynorbornen-based AEI.

[0097] (3) The anion exchange polymer prepared by the present invention has been successfully applied in alkaline water electrolysis equipment and has obtained excellent water electrolysis performance. Attached Figure Description

[0098] Figure 1 The trimethylamine ionomer prepared in Example 3 1 H NMR spectrum.

[0099] Figure 2 The image shows the polarization curve of water electrolysis in Example 7.

[0100] Figure 3 The results are from the durability test of electrolyzed water in Example 7.

[0101] Figure 4 The piperidine ionomer prepared in Example 5 1 H NMR spectrum.

[0102] Figure 5 The image shows the polarization curve of water electrolysis in Example 8.

[0103] Figure 6 The results are from the durability test of electrolyzed water in Example 8.

[0104] Figure 7 For Comparative Example 2 1 H NMR spectrum.

[0105] Figure 8 For Comparative Example 3 1H NMR spectrum. Detailed Implementation

[0106] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0107] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0108] Example 1

[0109]

[0110] This embodiment provides an addition copolymerization of BrNB and VNB, prepared by the following method:

[0111] As shown in the above procedure, 0.01 mmol Pd2(dba)3, 0.04 mmol PCy3, and 0.04 mmol LiFABA were first dissolved in 4 mL of toluene and stirred at room temperature for 1 h to prepare a catalyst solution. 2 mmol BrNB and 1 mmol VNB were dissolved in 4 mL of toluene to prepare a monomer solution. The catalyst solution was then filtered through a 0.45 μm filter membrane and added to the monomer solution. The mixture was stirred under a nitrogen atmosphere at room temperature. After the reaction was complete, the mixture was precipitated in methanol, sonicated, and filtered to obtain a pale yellow solid. This solid was then vacuum dried to obtain the addition polynorbornene copolymer, the structural formula of which is shown below:

[0112]

[0113] Where: n = 100, m = 50.

[0114] Example 2

[0115]

[0116] This embodiment provides an addition copolymer of BrNB and DCPD, prepared by the following method:

[0117] As shown in the above procedure, 0.01 mmol Pd2(dba)3, 0.04 mmol PCy3, and 0.04 mmol LiFABA were first dissolved in 4 mL of toluene and stirred at room temperature for 1 h to prepare a catalyst solution. 1.5 mmol BrNB and 1.5 mmol DCPD were dissolved in 4 mL of toluene to prepare a monomer solution. The catalyst solution was then filtered through a 0.45 μm filter membrane and added to the monomer solution. The mixture was stirred under a nitrogen atmosphere at room temperature. After the reaction was complete, the mixture was precipitated in methanol, sonicated, and filtered to obtain a pale yellow solid. This solid was then vacuum dried to obtain the addition polynorbornene copolymer, the structural formula of which is shown below:

[0118]

[0119] Where: n = 150, m = 150.

[0120] Example 3

[0121]

[0122] This embodiment provides the quaternization of addition polynorbornene copolymer, and the preparation method is as follows:

[0123] As shown in the above procedure, at room temperature, the addition polynorbornene copolymer (500 mg) from Example 1 was soaked in 2.5 mL of trimethylamine aqueous solution (30 wt%) for 48 hours. As the quaternization reaction proceeded, the product gradually dissolved in the trimethylamine aqueous solution after formation. The reaction continued until the addition polynorbornene copolymer was completely dissolved, resulting in a clear and transparent solution. After the reaction was complete, the trimethylamine was removed by rotary evaporation at 40 °C, and then the water was removed by vacuum drying at 60 °C to obtain 595 mg of ionomer, with a yield of 98%. Its structural formula is shown below:

[0124]

[0125] Where: n = 100, m = 50.

[0126] The ionomer prepared in this embodiment is soluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water at room temperature. 1 H NMR spectrum as shown Figure 1 As shown.

[0127] Example 4

[0128]

[0129] This embodiment provides the quaternization of addition polynorbornene copolymer, and the preparation method is as follows:

[0130] As shown in the above procedure, at room temperature, 500 mg of the addition polynorbornene copolymer from Example 2 was soaked in 2.5 mL of trimethylamine aqueous solution (30 wt%) for 48 hours. As the quaternization reaction proceeded, the product gradually dissolved in the trimethylamine aqueous solution after formation. The reaction continued until the addition copolymer was completely dissolved, resulting in a clear and transparent solution. After the reaction was complete, the trimethylamine was removed by rotary evaporation at 40 °C, and the water was removed by vacuum drying at 60 °C to obtain 550 mg of ionomer, with a yield of 95%. Its structural formula is shown below:

[0131]

[0132] Where: n = 150, m = 150.

[0133] The ionomer prepared in this embodiment is soluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water at room temperature.

[0134] Example 5

[0135]

[0136] This embodiment provides the quaternization of addition polynorbornene copolymer, and the preparation method is as follows:

[0137] As shown in the above process, 500 mg of the addition polynorbornene copolymer from Example 2 was mixed with a piperidine aqueous solution (30 wt%) and reacted at 60 °C for 12 h. As the quaternization reaction proceeded, the product gradually dissolved in the piperidine aqueous solution. The reaction continued until the addition copolymer was completely dissolved, yielding a clear, transparent yellow solution. After the reaction was complete, piperidine and water were removed by rotary evaporation at 60 °C, and the product was dried under vacuum to obtain 610 mg of ionomer, with a yield of 94%. Its structural formula is shown below:

[0138]

[0139] Where: n = 150, m = 150.

[0140] The ionomer prepared in this embodiment is soluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water. 1 H NMR spectrum as shown Figure 4 As shown.

[0141] Example 6

[0142]

[0143] This embodiment scales up the reaction in Example 3, and the preparation method is as follows:

[0144] As shown in the above procedure, at room temperature, the addition polynorbornene copolymer (20.0 g) from Example 1 was soaked in 100 mL of trimethylamine aqueous solution (30 wt%) for 48 hours. As the quaternization reaction proceeded, the product gradually dissolved in the trimethylamine aqueous solution after formation. The reaction continued until the addition polynorbornene copolymer was completely dissolved, resulting in a clear and transparent solution. After the reaction was complete, the trimethylamine was removed by rotary evaporation at 40 °C, and then the water was removed by vacuum drying at 60 °C to obtain 23.8 g of ionomer, with a yield of 98%. Its structural formula is shown below:

[0145]

[0146] Where: n = 100, m = 50.

[0147] The ionomer prepared in this embodiment is soluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water at room temperature.

[0148] Comparative Example 1

[0149]

[0150] This comparative example provides the quaternization of addition polynorbornene copolymers in NMP solvent. Under the premise of consuming the same amount of reaction solvent, the yield is significantly reduced, and a large amount of diethyl ether is required. The specific preparation method is as follows:

[0151] As shown in the above procedure, at 50°C, 1g of the addition polynorbornene copolymer prepared in Example 1 was first dissolved in 80mL of NMP and stirred for 5h. The polymer dispersed but did not dissolve. Then, 20mL of a 2mol / L trimethylamine ethanol solution was added, and stirring continued. As the reaction proceeded, the polymer gradually dissolved, resulting in a clear and transparent solution. The reaction lasted for 48h. After the reaction was completed, the solution was cooled to room temperature, precipitated with 500mL of diethyl ether, washed, and the solid product was collected by centrifugation, yielding 350mg of ionomer, with a yield of 29%. Its structural formula is shown below:

[0152]

[0153] Where: n = 100, m = 50.

[0154] The ionomers prepared in this comparative example are soluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water at room temperature.

[0155] Comparative Example 2

[0156]

[0157] This comparative example provides the quaternization of addition polynorbornene copolymers in THF solution, and the specific preparation method is as follows:

[0158] As shown in the above procedure, at room temperature, 1 g of the addition polynorbornene copolymer prepared in Example 1 was dissolved in 10 mL of THF, and then 1 mL of 30 wt% trimethylamine aqueous solution was added. The polynorbornene copolymer precipitated directly from the reaction, and the reaction proceeded for 48 h. After the reaction was completed, the product was collected by filtration and analyzed by nuclear magnetic resonance (NMR). Figure 7 The results showed that all samples were raw materials and no target reaction occurred. Furthermore, the resulting product was insoluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water.

[0159] Comparative Example 3

[0160]

[0161] This comparative example provides the quaternization of addition polynorbornene copolymers in THF solution, and the specific preparation method is as follows:

[0162] As shown in the above procedure, at room temperature, 1 g of the addition polynorbornene copolymer prepared in Example 1 was dissolved in 10 mL of THF, and then 1 mL of 1-methylpiperidine was added. The initial reaction was a clear solution; as the reaction proceeded for approximately 6 hours, polymer precipitated from the solution, and the reaction was maintained for 48 hours. After the reaction was complete, 1.05 g of the polymer was collected by filtration and analyzed by NMR (nuclear magnetic resonance). Figure 8 This indicates that its quaternization degree is approximately 50%, and its structural formula is shown below:

[0163]

[0164] Where: n' = 50, n” = 50, m = 50.

[0165] The ionomer prepared in this comparative example is insoluble in methanol, propanol, dimethyl sulfoxide, and mixed solvents with water at room temperature.

[0166] Example 7

[0167] This embodiment provides water electrolysis data for addition polynorbornene ionomers. The ionomer used is the ionomer prepared in Example 6; the membrane used is a cross-linked polynorbornene-based AEM (an AEM with OH- anions prepared in Example 22 of patent document application number ZL202210635715.9).

[0168] Membrane electrode (MEA) was prepared using a catalyst coating substrate method, as follows: the anode catalyst was NiFe, and the substrate was nickel foam; the cathode catalyst was Pt / C, and the substrate was carbon paper. The catalyst slurry composition during spraying was as follows: 180 mg catalyst, 18 mg ionomer, 15 mL propanol, and 3 mL water. The catalyst slurry was sprayed onto both the anode and cathode substrates, with a total catalyst and ionomer loading of 1.3 mg / cm³.2 .

[0169] The catalyst sheets were cut to 2.0 cm × 2.0 cm, the effective area of ​​the electrolytic cell was 2.0 cm × 2.0 cm, and the concentration of the KOH aqueous solution was 1.0 M. Using a battery test bench and temperature control device, voltages of 1.3 V–2.1 V were applied at 60 °C, the current at the corresponding voltages was measured, and polarization curves were plotted. The polarization curves are shown below. Figure 2 As shown, the results indicate that the current density is 2.7 A / cm² at 2V. 2 .

[0170] The durability test for electrolyzed water is conducted at 1000 mA / cm. 2 The voltage change was measured under constant current density, with a KOH aqueous solution concentration of 1M and a test temperature of 60℃. The durability test results are as follows: Figure 3 As shown, the results indicate that the water electrolysis device of the present invention can operate stably for 1200 hours.

[0171] Example 8

[0172] This embodiment provides data on the electrolysis of water using addition polynorbornene ionomers. The ionomer used is the one prepared in Example 5; the membrane used is a cross-linked polynorbornene-based AEM (an AEM with OH- anions prepared in Example 22 of patent document application number ZL202210635715.9).

[0173] Membrane electrode (MEA) was prepared using a catalyst coating substrate method, as follows: the anode catalyst was NiFe, and the substrate was nickel foam; the cathode catalyst was Pt / C, and the substrate was carbon paper. The composition of the catalytic slurry used in the spraying was as follows: 180 mg of catalyst, 18 mg of ionomer, 15 mL of propanol, and 3 mL of water. The catalytic slurry was sprayed onto both the anode and cathode substrates, with a total catalyst and ionomer loading of 2.0 mg / cm³. 2 .

[0174] The catalyst sheets were cut to 1.0 cm × 1.0 cm, the effective area of ​​the electrolytic cell was 1.0 cm × 1.0 cm, and the concentration of the KOH aqueous solution was 1.0 M. Using a battery test bench and temperature control device, voltages of 1.2 V–2.5 V were applied at 60 °C, the current at the corresponding voltages was measured, and polarization curves were plotted. The polarization curves are shown below. Figure 5 As shown, the results indicate that the current density is 1.7 A / cm² at 2V. 2 .

[0175] The durability test for electrolyzed water is conducted at 1000 mA / cm. 2The voltage change was measured under constant current density, with a KOH aqueous solution concentration of 1M and a test temperature of 60℃. The durability test results are as follows: Figure 6 As shown, the results indicate that the water electrolysis device of the present invention can operate stably for more than 250 hours.

[0176] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. 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. A method for preparing an ionomer, characterized in that, The preparation method includes the following steps: immersing the polynorbornene addition copolymer in an aqueous solution of a tertiary amine to carry out a quaternization reaction until the addition copolymer is completely dissolved to obtain a clear and transparent solution, thereby obtaining the ionomer; The tertiary amine is selected from N-methylpiperidine, N-methyltetrahydropyrrole, N-methylmorpholinine, N-ethylpiperidine, or tertiary amines having the structure shown in the following formula: ； The ionomer has a structure represented by at least one of the following formulas (I) to (III): ； in: R1 is -C 1-10 Alkylene-N + (R5)(R6)(R7)X - X is a halogen; R2 is selected from H and C. 1-10 Alkyl, C 1-10 Alkylene-X', C 6-14 Aryl, C 2-10 One of the alkenyl groups; X' is selected from halogens; R3 is C 2-10 alkenyl; R4 is selected from H and C. 1-10 Alkyl, C 6-14 Aryl, C 2-10 One of the alkenyl groups; The ratio of m to n is 1:10 to 10:1; R5, R6, and R7 may be the same or different and are independently selected from alkyl chains or cycloalkyl chains, and the total number of carbon atoms of R5, R6, and R7 does not exceed 10; or R5, R6, and R7 may be the same or different and are independently selected from oxygen-containing alkyl ether chains.

2. The preparation method according to claim 1, characterized in that, m and n are selected from 10 to 500; And / or, the X is Cl, Br, or I; And / or, the X' is Cl, Br or I; And / or, R1 is selected from -C 1-6 Alkylene-N + (R5)(R6) (R7)X - X is a halogen; And / or, R2 is selected from H, C 1-6 Alkyl, C 1-6 Alkylene-X', C 6-14 Aryl, C 2-6 One of the alkenyl groups, where X' is selected from halogens; And / or, R3 is C 2-6 alkenyl; And / or, R4 is selected from H, C 1-6 Alkyl, C 6-14 Aryl, C 2-6 One of the alkenyl groups.

3. The method for preparing the ionomer according to claim 1 or 2, characterized in that, m and n are selected from 20 to 300.

4. The preparation method according to claim 1, characterized in that, The tertiary amine is selected from one of the following structures: trimethylamine, triethylamine, tri-n-propylamine, N-methylpiperidine, N-methyltetrahydropyrrole, N-methylmorpholin, and N-ethylpiperidine.

5. The preparation method according to claim 1, characterized in that, The concentration of the aqueous solution of the tertiary amine is 10-50 wt%; And / or, the soaking temperature is 0 °C-95 °C; the soaking time is 10-96 h.

6. The application of the ionomer prepared by the preparation method according to any one of claims 1-5 in the preparation of membrane electrodes in the fields of fuel cells and water electrolysis.

7. A catalytic slurry, characterized in that, It includes ionomers prepared by the preparation method according to any one of claims 1-5.

8. The catalytic slurry as described in claim 7, characterized in that, The catalytic slurry also includes a catalyst and a solvent; And / or, the mass ratio of the catalyst to the ionomer is 20:1 to 1:

1.

9. A membrane electrode, characterized in that, It is prepared from the catalytic slurry described in claim 7.

10. An electrolytic cell, characterized in that, It includes the membrane electrode as described in claim 9.

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