Polyfluorene-based ionomer, anion exchange membrane, method for preparing the polyfluorene-based ionomer and method for fabricating the anion exchange membrane

Patent metadata

Field	Value
Publication number	US-12552897-B2
Application number	US-202017782548-A
Country	US
Kind code	B2
Filing date	Nov 9, 2020
Priority date	Dec 6, 2019
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A novel polyfluorene-based ionomer, an anion exchange membrane, a method for preparing the polyfluorene-based ionomer, and a method for fabricating the anion exchange membrane are proposed. The polyfluorene-based ionomer contains no aryl ether bonds in the polymer backbone and includes piperidinium groups incorporated into the repeating units. The anion exchange membrane is fabricated from the polyfluorene-based ionomer. The anion exchange membrane has good thermal and chemical stability, excellent mechanical properties, and high ion conductivity. Due to these advantages, the anion exchange membrane can be applied as a membrane for an alkaline fuel cell and to a binder for an alkaline fuel cell or water electrolysis.

First claim

The invention claimed is:

1 . A polyfluorene-based ionomer having repeating units, represented by Formula 1:

wherein the segments A, B, C, and D are identical to or different from each other and are each independently selected from

 with the proviso that at least one of the segments is

 and the sum of x, y, z, and m representing the mole fractions of the corresponding repeating units is 1.

2 . A method for preparing a polyfluorene-based ionomer, comprising: (I) dissolving fluorene or 9,9′-dimethylfluorene and 1-methyl-4-piperidone or fluorene or 9,9′-dimethylfluorene, 1-methyl-4-piperidone, and a compound selected from

or 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone as a comonomer in an organic solvent to form a solution; (II) adding a strong acid catalyst to the solution and allowing the solution to react with stirring; (III) precipitating the solution to obtain a precipitate and washing and drying the precipitate to obtain a solid polymer; (IV) dissolving the solid polymer in an organic solvent to form a polymer solution, adding K 2 CO 3 and an excess of a halomethane to the polymer solution, and allowing the polymer solution to react to form quaternary piperidinium salts; and (V) precipitating the polymer solution to obtain a precipitate and washing and drying the precipitate.

3 . The method according to claim 2 , wherein in step (I), the organic solvent comprises at least one halogenated solvent selected from the group consisting of dichloromethane, chloroform, dichloroethane, dibromomethane, and tetrachloroethane.

4 . The method according to claim 2 , wherein in step (II), the strong acid catalyst comprises at least one of trifluoroacetic acid, trifluoromethanesulfonic acid, pentafluoroethanesulfonic acid, heptafluoro-1-propanesulfonic acid, perfluoropropionic acid, heptafluorobutyric acid, or a mixture thereof.

5 . The method according to claim 2 , wherein in step (IV), the organic solvent comprises a mixture of at least one of N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide or dimethylformamide, and trifluoroacetic acid as a cosolvent.

6 . The method according to claim 2 , wherein in step (IV), the halomethane comprises at least one of fluoromethane, chloromethane, bromomethane or iodomethane.

7 . An anion exchange membrane comprising the polyfluorene-based ionomer according to claim 1 .

8 . A method for fabricating an anion exchange membrane, comprising: (a) dissolving the polyfluorene-based ionomer according to claim 1 in an organic solvent to form a polymer solution; (b) casting and drying the polymer solution on a glass plate to obtain a membrane; and (c) treating the membrane with 1 M NaOH, 1 M NaCl or 1 M Na 2 CO 3 , followed by washing the membrane with ultrapure water and drying the membrane.

9 . The method according to claim 8 , wherein the organic solvent comprises at least one of N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide or dimethylformamide.

10 . The method according to claim 8 , wherein the polymer solution has a concentration of 2 to 5% by weight.

11 . The method according to claim 8 , wherein in step (b), the drying is performed by heating in an oven at 80 to 90° C. for 24 hours to remove the organic solvent and heating in a vacuum oven at 120 to 150° C. for 24 hours to remove the organic solvent.

12 . A binder for an alkaline fuel cell comprising the polyfluorene-based ionomer according to claim 1 .

13 . A membrane electrode assembly for an alkaline fuel cell comprising the anion exchange membrane according to claim 7 .

14 . An alkaline fuel cell comprising the anion exchange membrane according to claim 7 .

15 . A water electrolysis device comprising the anion exchange membrane according to claim 7 .

Assignees

• Iucf Hyu

Inventors

• Lee Young Moo
• Chen Nanjun
• Wang Ho Hyun
• Kim Sun Pyo

Classifications

• H01M8/1004

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M4/8668

  Binders · CPC title

• C25B13/08 Primary

  based on organic materials · CPC title

• C25B1/04

  by electrolysis of water · CPC title

• C08J2365/00

  Characterised by the use of macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain (C08J2307/00 - C08J2357/00, C08J2361/00 take precedence); Derivatives of such polymers · CPC title