Polymer electrolyte membrane, method for preparing the membrane and fuel cell comprising the membrane

Patent metadata

Field	Value
Publication number	US-2022302488-A1
Application number	US-202117562440-A
Country	US
Kind code	A1
Filing date	Dec 27, 2021
Priority date	Mar 16, 2021
Publication date	Sep 22, 2022
Grant date	—

Abstract

The polymer electrolyte membrane includes: a first ion conductive polymer layer; and a second ion conductive polymer layer disposed on at least one surface of the first ion conductive polymer layer, wherein the first ion conductive polymer layer comprises a first ion conductive polymer comprising a sulfonic acid group, wherein the second ion conductive polymer layer comprises a second ion conductive polymer comprising a carboxylic acid group, and wherein a thickness of the second ion conductive polymer layer is in a range of 1% to 80% of a thickness of the polymer electrolyte membrane. Further, disclosed are the method for preparing the same, the membrane-electrode assembly including the same, and the fuel cell including the same.

First claim

What is claimed is:

1 . A polymer electrolyte membrane comprising:
a first ion conductive polymer layer; and a second ion conductive polymer layer disposed on at least one surface of the first ion conductive polymer layer, wherein the first ion conductive polymer layer comprises a first ion conductive polymer comprising a sulfonic acid group, wherein the second ion conductive polymer layer comprises a second ion conductive polymer comprising a carboxylic acid group, and wherein a thickness of the second ion conductive polymer layer is in a range of 1% to 80% of a thickness of the polymer electrolyte membrane.

2 . The polymer electrolyte membrane of claim 1 , wherein the second ion conductive polymer layer comprises:
a third ion conductive polymer layer disposed on at least one surface of the first ion conductive polymer layer; and a fourth ion conductive polymer layer disposed on one surface of the third ion conductive polymer layer, wherein the third ion conductive polymer layer comprises a third ion conductive polymer comprising the carboxylic acid group and the sulfonic acid group, and wherein the fourth ion conductive polymer layer comprises a fourth ion conductive polymer comprising the carboxylic acid group.

3 . The polymer electrolyte membrane of claim 2 , wherein a thickness of the third ion conductive polymer layer is in a range of 1 to 40% of the thickness of the polymer electrolyte membrane, and
wherein a thickness of the fourth ion conductive polymer layer is in a range of 1 to 40% of the thickness of the polymer electrolyte membrane.

4 . The polymer electrolyte membrane of claim 2 , wherein the third ion conductive polymer layer has a first concentration gradient of the carboxylic acid group and a second concentration gradient of the sulfonic acid group.

5 . The polymer electrolyte membrane of claim 4 , wherein
the first concentration gradient of the carboxylic acid group increases in a thickness direction from the first ion conductive polymer layer to the fourth ion conductive polymer layer, and the second concentration gradient of the sulfonic acid group decreases in the thickness direction from the first ion conductive polymer layer to the fourth ion conductive polymer layer.

6 . The polymer electrolyte membrane of claim 1 , wherein the polymer electrolyte membrane comprises:
the first ion conductive polymer layer; and the second ion conductive polymer layer disposed one surface of the first ion conductive polymer layer, wherein the thickness of the second ion conductive polymer layer is in a range of 1 to 40% of the thickness of the polymer electrolyte membrane.

7 . The polymer electrolyte membrane of claim 1 , wherein the polymer electrolyte membrane comprises:
the first ion conductive polymer layer; and a plurality of the second ion conductive polymer layers respectively disposed on both opposing surfaces of the first ion conductive polymer layer, wherein a thickness of each of the plurality of the second ion conductive polymer layers is in a range of 1 to 40% of the thickness of the polymer electrolyte membrane.

8 . The polymer electrolyte membrane of claim 1 , wherein the thickness of the polymer electrolyte membrane is in a range of 10 μm to 100 μm.

9 . The polymer electrolyte membrane of claim 1 , wherein the first ion conductive polymer comprises a sulfonated product of at least one polymer selected from the group consisting of a fluoropolymer, a hydrocarbon-based polymer, and a partially fluorinated polymer.

10 . The polymer electrolyte membrane of claim 1 , wherein the first ion conductive polymer layer comprises a porous substrate.

11 . The polymer electrolyte membrane of claim 1 , wherein the polymer electrolyte membrane has a hydrogen permeability of 18.5 Barrer or less at 70° C. as measured using a time-lag method.

12 . The polymer electrolyte membrane of claim 1 , wherein the polymer electrolyte membrane has an oxygen permeability of less than 4.0 Barrer at 70° C. as measured using a time-lag method.

13 . A method for preparing a polymer electrolyte membrane comprising:
preparing a first ion conductive polymer membrane comprising a first ion conductive polymer layer comprising a sulfonic acid group; performing a chlorination reaction on at least one surface of the first ion conductive polymer membrane for 5 to 30 minutes such that a second ion conductive polymer membrane comprising a chlorinated ion conductive polymer layer is formed on at least one surface of the first ion conductive polymer layer, wherein the chlorinated ion conductive polymer layer is formed by partially chlorinating the sulfonic acid group; performing a nitrilation reaction on the second ion conductive polymer membrane such that a third ion conductive polymer membrane comprising a nitrilated ion conductive polymer layer is formed on at least one surface of the first ion conductive polymer layer, wherein the nitrilated ion conductive polymer layer is formed by replacing a chlorine in the chlorinated ion conductive polymer layer with a nitrile group; performing a hydrolysis reaction on the third ion conductive polymer membrane such that a fourth ion conductive polymer membrane comprising a second ion conductive polymer layer is formed on at least one surface of the first ion conductive polymer layer, wherein the second ion conductive polymer layer is formed by replacing the nitrile group of the nitrilated ion conductive polymer layer with a carboxylic acid group; and performing heat treatment on the fourth ion conductive polymer membrane at ±10° C. around a glass transition temperature of an ion conductive polymer comprising a carboxylic acid group, thereby preparing the polymer electrolyte membrane, wherein a thickness of the second ion conductive polymer layer is in a range of 1 to 80% of a thickness of the polymer electrolyte membrane.

14 . The method of claim 13 , wherein the performing the chlorination reaction comprises immersing the first ion conductive polymer membrane in a chlorination reaction solution comprising a hydrochloric acid and an ammonium chloride.

15 . A membrane-electrode assembly comprising a negative-electrode; a positive-electrode; and a polymer electrolyte membrane comprising the polymer electrolyte membrane of claim 1 , interposed between the negative-electrode and the positive-electrode.

16 . A fuel cell comprising the membrane-electrode assembly of claim 15 .

Assignees

• Hyundai Mobis Co Ltd
• Univ Dankook Cheonan Campus Ind Academic Cooperation Foundation

Inventors

• Heo Pil Won
• Lee Sung Chul
• Kang Eun Heui
• Choi Seung Kyu
• Jeong Ki Young
• Lee Chang Hyun
• Park In Kee

Classifications

• H01M8/1053 Primary

  consisting of layers of polymers with at least one layer being ionically conductive · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/1088

  Chemical modification, e.g. sulfonation · CPC title

• H01M8/1067

  characterised by their physical properties, e.g. porosity, ionic conductivity or thickness · CPC title

• H01M8/1081

  starting from solutions, dispersions or slurries exclusively of polymers · CPC title