CN-121574485-B - Polynorbornene-based composite anion exchange membrane and preparation method and application thereof

Abstract

The invention discloses a polynorbornene-based composite anion exchange membrane, a preparation method and application thereof, wherein the composite anion exchange membrane comprises polysulfone resin and ionic polynorbornene, or comprises polybenzimidazole resin and ionic polynorbornene, or comprises polysulfone resin, polybenzimidazole resin and ionic polynorbornene. According to the polynorbornene based composite anion exchange membrane, the polysulfone resin or the polybenzimidazole resin is introduced into the ionic polynorbornene, so that the mechanical strength of the anion exchange membrane in a wet membrane state can be remarkably improved, the polynorbornene based composite anion exchange membrane can be used for assembling more stable water electrolysis devices, and the durability is improved.

Inventors

• YOU WEI
• ZHANG HAIXIA
• WANG YU
• XIAO YUBING
• SUN SHUANG
• CAI JINGYANG
• GUO HESONG
• LI XIANG

Assignees

• 中国科学院化学研究所
• 北京清玮膜科技有限公司

Dates

Publication Date

20260512

Application Date

20260129

Claims (10)

1. 1. A polynorbornene based composite anion exchange membrane for use in an anion exchange membrane electrolyzed water or an anion exchange membrane fuel cell, the composite anion exchange membrane comprising a polysulfone resin and an ionic polynorbornene, or the composite anion exchange membrane comprising a polybenzimidazole resin and an ionic polynorbornene; The mass ratio of the polysulfone resin to the ionic polynorbornene is 1:1-20; The mass ratio of the polybenzimidazole resin to the ionic polynorbornene is 1:1-20; The ionic polynorbornene comprises a polynorbornene high molecular skeleton polymer, and the side chain of the polymer contains quaternary ammonium cation functional groups, wherein the quaternary ammonium cation functional groups are at least one selected from alkyl-trimethylamine cations and alkyl-N-methylpiperidine cations; the polynorbornene high molecular skeleton is a polymer main chain obtained by taking norbornene with a bicyclo [2.2.1] -2-heptene as a core structure as a monomer; the preparation method of the ionic polynorbornene comprises the following steps: Firstly, 0.01 mmol Pd 2 (dba) 3 、0.04 mmol PCy 3 and 0.04 mmol LiFABA are dissolved in 4 mL toluene, and stirred at room temperature for 1h to prepare a catalyst solution, 2mmol BrNB and 1 mmol VNB are dissolved in 4 mL toluene to prepare a monomer solution, and then the catalyst solution is treated with 0.45 M, adding the mixture into a monomer solution, stirring the mixture at room temperature, precipitating the mixture in methanol after the reaction is finished, carrying out ultrasonic treatment, carrying out suction filtration to obtain a pale yellow solid, and carrying out vacuum drying to obtain the addition polynorbornene copolymer; stirring the polynorbornene copolymer in NMP for 5 hours at 50 ℃, dispersing the polymer but not dissolving the polymer, then adding an ethanol solution of trimethylamine, continuing stirring, gradually dissolving the polymer along with the progress of the reaction to obtain a clear and transparent solution, and carrying out the reaction for 48 hours; the polysulfone resin is a polymer with sulfonyl groups on a molecular main chain, and two sides of the polysulfone resin are connected with aromatic rings; the number average molecular weight of the polysulfone resin is 2-10 ten thousand; the number average molecular weight of the ionic polynorbornene is 2 to 50 ten thousand; the number average molecular weight of the polybenzimidazole resin ranges from 2 ten thousand to 10 ten thousand.
2. 2. The composite anion exchange membrane of claim 1, wherein the polysulfone resin is selected from at least one of bisphenol a-containing polysulfone, ether linkage-containing polyethersulfone, biphenyl-containing polyphenylsulfone, phenyl-containing polyphenylsulfone, and polyarylsulfone containing multiple aromatic rings and heteroatoms.
3. 3. The composite anion exchange membrane of claim 1, wherein the ionic polynorbornene has an ion exchange capacity of 0.5 to 3.0 mmol/g.
4. 4. The composite anion exchange membrane of claim 1, wherein the polybenzimidazole resin is a polymer containing benzimidazole repeat units in the molecular backbone.
5. 5. The composite anion exchange membrane of claim 4, wherein the polybenzimidazole resin is selected from at least one of poly [2,2'- (m-phenylene) -5,5' -bisbenzimidazole ], poly [2,5- (1, 3-phenylene) benzimidazole ], poly (2, 2 '-diphenyl ether-5, 5' -bisbenzimidazole), poly (2, 2 '-diphenyl sulfone-5, 5' -bisbenzimidazole), and poly (2, 2 '-hexafluoroisopropyl-5, 5' -bisbenzimidazole).
6. 6. The method for preparing a composite anion exchange membrane according to any one of claims 1 to 5, wherein the method comprises: mixing polysulfone resin solution or polybenzimidazole resin solution with ionic polynorbornene solution, and forming a film from the obtained mixed solution to obtain the composite anion exchange membrane.
7. 7. The method according to claim 6, wherein the polysulfone resin solution is prepared by dissolving polysulfone resin in a polar organic solvent, and the concentration of the polysulfone resin solution is 1-10wt%.
8. 8. The method according to claim 6, wherein the polybenzimidazole resin solution is prepared by dissolving polybenzimidazole resin in a polar organic solvent, and the concentration of the polybenzimidazole resin solution is 1-10wt%.
9. 9. The method according to claim 6, wherein the ionic polynorbornene solution is prepared by dissolving ionic polynorbornene in a polar organic solvent, and the concentration of the ionic polynorbornene solution is 1 to 25wt%; And/or the polar organic solvent is at least one selected from N, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone.
10. 10. Use of an anion exchange membrane according to any one of claims 1-5 in an anion exchange membrane electrolysis of water or an anion exchange membrane fuel cell.

Description

Polynorbornene-based composite anion exchange membrane and preparation method and application thereof Technical Field The invention belongs to the technical field of anion exchange membrane preparation, and particularly relates to a polynorbornene based composite anion exchange membrane, and a preparation method and application thereof. Background Hydrogen energy, which generates only water when burned or generated by a fuel cell without discharging carbon dioxide, becomes a key carrier for achieving the prospect of global carbon neutralization. The process of producing hydrogen and oxygen from renewable electricity-driven electrolyzed water is known as "green hydrogen" production. Among the numerous water electrolysis technologies, the Anion Exchange Membrane (AEM) electrolysis of water to produce hydrogen is considered as the next generation of the most potential large-scale green hydrogen production technology due to the low cost material system of alkaline cells and the high efficiency, fast response advantages of Proton Exchange Membrane (PEM) cells. The anion exchange membrane electrolyzed water (AEMWE) and the Anion Exchange Membrane Fuel Cell (AEMFC) can use non-noble metal catalysts, have faster cathode reaction kinetics, and are key devices for the efficient generation and utilization of hydrogen. An Anion Exchange Membrane (AEM) is one of the key components of AEMFCs and AEMWE, having a crucial impact on the performance and durability of the device. As a polymer material, AEM is mainly composed of a polymer backbone, covalently linked cationic functional groups, and free mobile anions. Among the polymer skeletons of controllable selection, polynorbornene has a main chain structure of full hydrocarbon, so it has excellent thermal stability and chemical stability, and at the same time, it has no benzene ring structure, so it becomes a promising AEM skeleton, and compared with the polyaryl skeleton catalyzed by super acid, the polynorbornene synthesis process is in full neutral condition, and it has no need of using super acid such as trifluoro methane sulfonic acid as solvent, so it can avoid the secondary problems of equipment corrosion and environmental pollution. However, a major problem of the current polynorbornene-based AEM is that its anti-swelling properties and mechanical properties are insufficient, and because of the lack of strong interactions between molecular chains such as benzene rings in the structure of polynorbornene, it is easy to absorb water and excessively swell after introducing ionic functional groups, thus further reducing its mechanical properties. One common strategy is therefore to control the water-absorbing swelling by introducing a cross-linking structure. For example, kohl et al (ACS appl. Energy match 2019, 2, 2447-2457) cross-links with diamine cations, but still does not control swelling effectively, and therefore requires the incorporation of porous Polytetrafluoroethylene (PTFE) substrates for even further composite reinforcement. However, the polymer material has a slow diffusion rate in the porous substrate, and thus cannot be completely filled, which also results in poor gas barrier performance of such a porous substrate-based composite ion exchange membrane. In addition, there is also a UV crosslinking strategy based on dithiol (J.Member. Sci. 2024, 702, 122747|1-10; CN117229451B), which has high ionic conductivity but poor mechanical properties, and has tensile breaking strength and strain in the dry state of 36 MPa and 19%, respectively, which is further reduced under wet conditions, and which cannot withstand the assembly strength and barrier gas requirements of ion exchange membranes in electrochemical devices. Therefore, how to improve the mechanical strength and the service life of the AEM under the premise of ensuring the high conductivity of the AEM is a technical problem to be solved urgently. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a polynorbornene-based composite anion exchange membrane, a preparation method and application thereof, wherein the composite anion exchange membrane has obviously improved fracture strain in a wet state, and simultaneously has improved gas resistance after long-term stability test, ensures that a device can stably operate for a long time, and has good development prospect. Based on the above, the technical scheme of the invention is as follows: A polynorbornene based composite anion exchange membrane comprising a polysulfone resin and an ionic polynorbornene, or comprising a polybenzimidazole resin and an ionic polynorbornene, or comprising a polysulfone resin, a polybenzimidazole resin and an ionic polynorbornene. According to the embodiment of the invention, the mass ratio of the polysulfone resin to the ionic polynorbornene is 1:1-20, preferably 1:2-10. According to the embodiment of the invention, the mass ratio of the polybenzimidazole resin to the ionic polyno