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CN-122011316-A - Grafted sulfonated polymer membrane containing spiro structure and preparation method and application thereof

CN122011316ACN 122011316 ACN122011316 ACN 122011316ACN-122011316-A

Abstract

The invention discloses a grafted sulfonated polymer membrane containing a spiro structure, a preparation method thereof and application thereof in an electrochemical energy storage device, and belongs to the technical field of polymer separation membranes. The membrane material comprises a polymer prepared by polymerization reaction, wherein the monomers of the polymerization reaction comprise aromatic monomers with spiro indane structures and monomers containing imidazole groups, and the membrane material is characterized in that a side chain containing sulfonic acid groups is grafted on nitrogen atoms of the imidazole groups in a repeating unit of the polymer. The preparation method comprises the steps of carrying out polymerization reaction on the two monomers to obtain a precursor polymer, then, reacting the precursor polymer with a sulfonating agent to realize grafting of a sulfonic side chain on an imidazole group nitrogen atom, and finally, preparing a film by a solution casting method. According to the invention, the sulfonic side chain is introduced into the spiro polymer skeleton with high chemical stability in a grafting way, so that a high-efficiency ion conduction channel is constructed, meanwhile, the structural stability of the membrane material is maintained, and the prepared membrane material has excellent comprehensive performance in applications such as alkaline aqueous organic flow batteries.

Inventors

  • XU ZHI
  • HUANG KANG
  • LU YUQIN

Assignees

  • 南京工业大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. A sulfonated polymer membrane material comprises a polymer prepared by polymerization reaction, wherein the monomer of the polymerization reaction comprises an aromatic monomer with a spiro indane structure and a monomer containing an imidazole group, and is characterized in that a side chain containing a sulfonic acid group is grafted on a nitrogen atom of the imidazole group in a repeating unit of the polymer.
  2. 2. The membrane material according to claim 1, wherein the aromatic monomer with a spiro indane structure is6, 6' -dimethoxy-3, 3' -tetramethyl-1, 1' -spiro indane, and the imidazole group-containing monomer is 1H-imidazole-4-carbaldehyde.
  3. 3. The membrane material according to claim 1 or 2, wherein the side chain containing a sulfonic acid group has a structure represented by formula I, -R-SO 3 -M+ (formula I), wherein R is an alkylene group of C 1 -C 6 , M+ is a hydrogen ion, an alkali metal ion or an ammonium ion, and preferably the side chain containing a sulfonic acid group is introduced from sodium 3-bromopropanesulfonate.
  4. 4. A method of preparing the sulfonated polymer membrane material of any one of claims 1-3, comprising the steps of: a) Carrying out polymerization reaction on an aromatic monomer with a spiro indane structure and a monomer containing an imidazole group in the presence of an acid catalyst to obtain a precursor polymer; b) Reacting the precursor polymer with a sulfonating agent containing a sulfonic group under alkaline conditions, so that the sulfonating agent is grafted onto the nitrogen atom of the imidazole group of the precursor polymer to obtain a sulfonated polymer; c) And dissolving the sulfonated polymer in a solvent to prepare a film casting solution, and preparing a film forming material by adopting a solution casting method.
  5. 5. The process according to claim 4, wherein the aromatic monomer having a spiro indane structure in step a) is 6,6' -dimethoxy-3, 3' -tetramethyl-1, 1' -spiro indane, the imidazole group-containing monomer is 1H-imidazole-4-carbaldehyde, and the acid catalyst is methanesulfonic acid or other organic sulfonic acid.
  6. 6. The method according to claim 6, wherein in the step a), the molar ratio of the imidazole group-containing monomer to the aromatic monomer having a spiro indane structure is 1.0:1 to 1.5:1, and the amount of methanesulfonic acid is 500to 1000 mL per mole of the aromatic monomer having a spiro indane structure.
  7. 7. The process of claim 5 wherein the sulfonating agent in step b) is a compound of the formula X-R-SO 3 -M+ wherein X is halogen, R is C 1 -C 6 alkylene and M+ is an alkali metal ion, the alkaline condition being achieved by addition of potassium hydroxide or other alkali metal hydroxide; the molar ratio of the sulfonating agent to imidazole groups in the precursor polymer in step b) is 0.40 to 1.20, preferably the molar ratio is 0.60 to 1.00; the reaction temperature in step b) is 60-100℃and the reaction time is 4-12 hours, preferably 75-85℃and the reaction time is 5-8 hours.
  8. 8. The method of claim 5, further comprising the step of pre-treating the membrane material produced in step c), said pre-treatment comprising sequentially immersing in an acidic solution and an alkaline solution.
  9. 9. Use of a sulfonated polymer membrane material as defined in any one of claims 1 to 3 in an electrochemical energy storage device.
  10. 10. The use according to claim 9, wherein the electrochemical energy storage device is an aqueous organic flow battery.

Description

Grafted sulfonated polymer membrane containing spiro structure and preparation method and application thereof Technical Field The invention relates to a microporous polymer with a rigid twisted spiro-indan framework, a prepared diaphragm and an organic flow battery, and belongs to the technical field of flow battery diaphragms. Background Along with the development of renewable energy sources, the dependence on matched energy storage technologies is also growing. In electrochemical energy storage solutions, flow batteries have unique advantages such as capacity and power decoupling designs. Particularly those emerging aqueous organic flow batteries (AORFBs) utilizing organic materials as the active species, avoiding highly contaminating and expensive heavy metal ions are leading to research in this area. Although most AORFBs operate at relatively mild pH and redox conditions, the requirements for battery components are low, they are extremely dependent on membrane materials in terms of ion conduction and active species separation. Therefore, a film having high ion conductivity and selectivity is urgently required to improve efficiency and stability of the battery. Ion conducting membranes currently in use are composed primarily of functional polymers, represented by commercial perfluorosulfonic acid polymers and low cost aromatic substitutes. Despite their mature processing technology, the backbones of these membranes are tightly packed and intertwined, preventing the formation of continuous ion transport channels. To address this limitation, researchers have explored the introduction of voids or channels permeable to electrolytes as additional ion transport pathways. Although micro-or sub-micro-scale voids may be formed by porogens or phase inversion methods, pores at nano-or sub-nano-scale have inherent advantages in selective ion transport. However, achieving such fine-scale channels generally requires precise molecular design of the polymer to loosen chain packing. One strategy to make microwells is to use molecules with rigid and twisted structures as the polymer building blocks. This structure prevents close packing of the polymer chains and forms inter-chain voids. Such materials, known as self-contained microporous Polymers (PIMs), retain linear macromolecular character without cross-linking, thereby retaining excellent solution processability. Because of these unique advantages, PIM-based membranes show great potential in terms of ion conduction. Nevertheless, the microporous structure serves only as a potential ion transport channel. In order to achieve rapid ion transport, it is essential to introduce functional groups into the membrane. While existing aggressive modification methods can enhance ion transport capacity, they tend to result in membranes with too high water absorption, thereby causing a high degree of swelling. In addition, most PIM membranes are limited by synthesis conditions, and only possess a single ion transport function (e.g., sulfonic acid groups), making it impossible to fully utilize the transport potential of the multiple carrier ions in AORFBs, specifically to the hydroxide ions and potassium ions in this work. Thus, designing ion conducting membranes with appropriate functionality tailored to AORFBs remains a challenge for the researchers. Disclosure of Invention In order to solve the above problems, the present invention innovatively integrates the rigid twisted spiroindane framework and imidazole functional groups into a single polymer structure by one-step acid catalyzed Friedel-Crafts polymerization, simplifying the multi-step synthesis process traditionally required for functionalized PIMs (a of fig. 1). A sulfonated polymer membrane material comprises a polymer prepared by polymerization reaction, wherein the monomer of the polymerization reaction comprises an aromatic monomer with a spiro indane structure and a monomer containing an imidazole group, and is characterized in that a side chain containing a sulfonic acid group is grafted on a nitrogen atom of the imidazole group in a repeating unit of the polymer. The aromatic monomer with the spiro indane structure is 6,6' -dimethoxy-3, 3' -tetramethyl-1, 1' -spiro indane, and the monomer containing the imidazole group is 1H-imidazole-4-formaldehyde. The structure of the side chain containing the sulfonic acid group is shown as a formula I, namely-R-SO 3 -M+ (formula I), wherein R is alkylene of C 1-C6, M+ is hydrogen ion, alkali metal ion or ammonium ion, and preferably, the side chain containing the sulfonic acid group is introduced by sodium 3-bromopropanesulfonate. The thickness of the film material is 20-150 μm, preferably 50-70 μm. A method of preparing the sulfonated polymer membrane material comprising the steps of: a) Carrying out polymerization reaction on an aromatic monomer with a spiro indane structure and a monomer containing an imidazole group in the presence of an acid catalyst to obtain a precursor