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CN-122011460-A - Preparation method of high-stability and high-conductivity composite anion exchange membrane

CN122011460ACN 122011460 ACN122011460 ACN 122011460ACN-122011460-A

Abstract

The invention belongs to the field of functional polymer membrane materials, and discloses a preparation method of a high-stability and high-conductivity composite anion exchange membrane. The composite porous anion exchange membrane is formed by compositing anion exchange and a porous phase inversion layer, adding the grafted modified nano inorganic filler into casting solution, uniformly mixing, scraping and coating on a non-porous anion exchange layer, and curing a wet membrane by phase inversion to obtain the composite porous anion exchange membrane. The grafting group can form a continuous hydrogen bond network and a hydration layer, a high-efficiency ion transmission channel is constructed, the ion migration activation energy is reduced, the remarkable improvement of the conductivity is realized, the chemical stability of the membrane at high temperature is enhanced through a gradient barrier effect, and the high efficiency unification of the high conductivity and the high chemical stability is realized. The composite anion exchange membrane with a non-porous/porous structure has high tensile strength, obviously improved conductivity, obviously reduced attenuation rate, obviously improved chemical stability and excellent comprehensive performance.

Inventors

  • LIN XIAO
  • Xu Shaodie
  • Jiang Zhengchao

Assignees

  • 安极能源(广东)有限公司

Dates

Publication Date
20260512
Application Date
20260114

Claims (10)

  1. 1. The preparation method of the composite porous anion exchange membrane is characterized in that the composite porous anion exchange membrane is formed by compositing a nonporous anion exchange layer and a porous phase inversion layer, and comprises the following steps: grafting modification is carried out on the surface of the nano inorganic filler by using a grafting agent containing quaternary amine groups, so as to obtain grafted nano inorganic filler; Dissolving an organic high molecular polymer in an organic solvent, heating and stirring to dissolve the organic high molecular polymer completely to obtain a phase inversion casting solution; adding the grafted nano inorganic filler into the phase inversion casting solution, and fully mixing to obtain a mixed phase inversion casting solution; and (3) carrying out blade coating on the mixed phase inversion casting solution on the surface of the nonporous anion exchange layer to form a phase inversion wet film, and then solidifying the phase inversion wet film by using a phase conversion method to obtain the composite porous anion exchange film.
  2. 2. The method according to claim 1, wherein the nano inorganic filler is at least one selected from the group consisting of nano zirconia, nano silica, nano layered double metal hydroxide, nano cerium oxide, nano aluminum oxide, nano magnesium oxide, and nano titanium oxide.
  3. 3. The method according to claim 1, wherein the organic polymer in the phase inversion casting solution is at least one selected from the group consisting of polysulfones, polyethersulfones, polyetheretherketones, polyvinylchlorides, polyaryletherketones, poly (biphenylalkyl) s, and poly (aryl-piperidine) styrenes.
  4. 4. The method according to claim 1, wherein the organic solvent is at least one selected from the group consisting of dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide, N-dimethylpropionamide, and N-methyl-2-pyrrolidone.
  5. 5. The preparation method according to claim 1, wherein the grafting agent containing quaternary amine groups is at least one selected from the group consisting of N- (3-trimethoxysilylpropyl) -N, N, N-trimethylammonium chloride, 3-triethoxysilylpropyl dimethyl octadecyl ammonium chloride, bis-quaternary amine silane, and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified silane.
  6. 6. The method according to any one of claims 1 to 5, wherein the method for graft modification comprises: pretreating and drying the nano inorganic filler to obtain an activated nano inorganic filler; dissolving a grafting agent in ethanol, dropwise adding deionized water, adjusting the pH to 5-6, and fully dispersing to obtain a grafting agent solution; Adding the activated nano inorganic filler into a grafting agent solution, fully mixing and reacting, and preferably, adding the grafting agent excessively; and after the reaction is finished, washing to remove unreacted grafting agent, and drying to obtain the grafted nano inorganic filler.
  7. 7. The method according to any one of claims 1 to 5, wherein the mass of the grafted nano inorganic filler and the organic high molecular polymer in the mixed phase inversion casting solution is (1 to 6): 1 to 30% In the mixed phase inversion casting film liquid, the content of the organic high molecular polymer is 5-30wt%, and the content of the grafted nano inorganic filler is 1-30wt%.
  8. 8. The method according to any one of claims 1 to 5, wherein the thickness of the nonporous anion exchange layer is 30 to 200 μm, the thickness of the porous phase inversion layer is 5 to 50 μm, and the thickness of the composite anion exchange membrane is 35 to 250m.
  9. 9. The method of claim 1, wherein the non-porous anion exchange layer preparation method comprises: Dissolving an organic high molecular polymer in an organic solvent, heating and stirring to dissolve the organic high molecular polymer completely to obtain a casting solution; The casting solution was prepared into a nonporous anion exchange layer by a knife coating method.
  10. 10. A composite anion exchange membrane prepared by the preparation method according to any one of claims 1 to 9.

Description

Preparation method of high-stability and high-conductivity composite anion exchange membrane Technical Field The invention belongs to the field of functional polymer membrane materials, and particularly relates to a preparation method of a high-stability and high-conductivity composite anion exchange membrane. Background An Anion Exchange Membrane (AEM) is used as a functional polymer membrane material capable of selectively transmitting anions, the core structure of the anion exchange membrane material is composed of a polymer main chain and a cation functional group, the main chain provides mechanical support and thermal stability, and the functional group endows ion conductivity and plays a key role in the fields of energy conversion, water treatment, chemical separation and the like. Currently, the mainstream is based on polymer skeletons such as polyarylether, polysulfone, polybenzimidazole and the like, and cationic groups (such as quaternary ammonium salt, piperidine salt and the like) are introduced through quaternization, imidazolium modification and the like, so that nanoscale channels capable of conducting anions such as OH-, cl-and the like are formed. While AEMs represent a great need and potential in the market, their technological development still faces a number of difficult problems. For example, currently marketed AEMs are generally faced with a core problem in which ion conduction efficiency and chemical stability are difficult to compromise. Although the traditional quaternary ammonium salt group is simple and convenient to synthesize and has higher ion exchange capacity (1.5-3.5 meq/g), degradation reactions such as Huffman elimination, nucleophilic substitution and the like are easy to occur in a high-temperature alkaline environment, so that the conductivity is fast attenuated, even the stability of the novel cyclic ammonium group such as piperidine salt and the like is obviously influenced by a main chain structure, the rigidity of a main chain is enhanced, the cation degradation rate is increased from 3% to 13%, and the loss rate in a 5M alkaline environment is even up to 40%. In order to solve the stability problem, the scientific and technological staff find that adding alkali-resistant metal oxide and alkali-resistant metal hydroxide into the anion exchange membrane can improve the stability and serve as a common means. From the principle aspect, the heat resistance of the membrane material in a high-temperature environment can be effectively enhanced by utilizing the self alkali-resistant chemical structure and stability of the nano inorganic filler, so that degradation reactions such as Huffman elimination, nucleophilic substitution and the like are reduced, and the chemical stability of the membrane material is further improved. In the traditional process of adding alkali-resistant nano inorganic filler, the occurrence of degradation reaction can be reduced, and the chemical stability of the alkali-resistant nano inorganic filler can be improved. However, the process often has the influence of Van der Waals force among inorganic powder, and the influence causes uneven dispersion, poor compatibility and easy agglomeration of the inorganic powder, so that the problems of ion channel blockage, ion conduction path lengthening, continuity reduction and the like are caused, and further the ion conduction rate is obviously reduced, so that the ion conduction efficiency and the chemical stability are difficult to be simultaneously considered. Disclosure of Invention The invention aims to overcome at least one defect of the prior art and provide a preparation method of a high-stability and high-conductivity composite anion exchange membrane. The technical scheme adopted by the invention is as follows: In a first aspect of the invention, there is provided: the preparation method of the composite porous anion exchange membrane is characterized in that the composite porous anion exchange membrane is formed by compositing a nonporous anion exchange layer and a porous phase inversion layer, and comprises the following steps: grafting modification is carried out on the surface of the nano inorganic filler by using a grafting agent containing quaternary amine groups, so as to obtain grafted nano inorganic filler; Dissolving an organic high molecular polymer in an organic solvent, heating and stirring to dissolve the organic high molecular polymer completely to obtain a phase inversion casting solution; adding the grafted nano inorganic filler into the phase inversion casting solution, and fully mixing to obtain a mixed phase inversion casting solution; and (3) carrying out blade coating on the mixed phase inversion casting solution on the surface of the nonporous anion exchange layer to form a phase inversion wet film, and then solidifying the phase inversion wet film by using a phase conversion method to obtain the composite porous anion exchange film. In some examples, the nano inorganic fi