POLYMER ELECTROLYTE FILM

• US 20170005354A1
• Filed: 12/01/2014
• Published: 01/05/2017
• Est. Priority Date: 11/29/2013
• Status: Active Grant

• Current Assignee: Asahi Kasei Kabushiki Kaisha, Daikin Industries Ltd
• Original Assignee: Asahi Kasei E-materials Corporation (Asahi Kasei Corporation), Daikin Industries Ltd
• Inventors: MIYAZAKI, Kuon, KIKUCHI, Kentaro, URAOKA, Nobuki, CHAEN, Shinichi, KONISHI, Tomohisa, INO, Tadashi, INOUE, Yuichi
• Granted Patent: US 10,944,121 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2323/42 Details of membrane preparation apparatus
• CPC Class Codes: B01D 2325/14 Membrane materials having negatively charged functional groups
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: B01D 71/82 characterised by the presence of specified groups, e.g. introduced by chemical after-treatment
• CPC Class Codes: C08J 2327/18 Homopolymers or copolymers of tetrafluoroethylene
• CPC Class Codes: C08J 2427/12 containing fluorine atoms
• CPC Class Codes: C08J 5/2237 containing fluorine
• CPC Class Codes: H01B 1/122 Ionic conductors
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 8/1025 having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1044 Mixtures of polymers, of which at least one is ionically conductive
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The present invention provides a polymer electrolyte membrane having excellent strength, a small dimensional change, and a low membrane resistance. The polymer electrolyte membrane includes a porous film having pores and a polymer electrolyte contained in the pores. The porous film is obtained by copolymerizing tetrafluoroethylene and an ethylenic comonomer to provide polytetrafluoroethylene and then stretching the polytetrafluoroethylene. The porous film has an average pore size of greater than 0.20 μm.

Claims

1. A polymer electrolyte membrane comprising

a porous film having pores;

and

a polymer electrolyte contained in the pores,

the porous film being obtained by copolymerizing tetrafluoroethylene and an ethylenic comonomer to provide polytetrafluoroethylene and then stretching the polytetrafluoroethylene,

the porous film having an average pore size of greater than 0.20 μ

m.

2. The polymer electrolyte membrane according to claim 1,

wherein the polymer electrolyte is a fluoropolymer electrolyte.

3. The polymer electrolyte membrane according to claim 2,

wherein the fluoropolymer electrolyte is a copolymer comprising:

a repeating unit derived from a COOZ or SO₃Z group-containing monomer represented by the following formula (I);

CF₂═

CF(CF₂)_k—

O₁—

(CF₂CFY¹—

O)_n—

(CFY²)_m-A¹ 

 

(I)

wherein Y¹ is F, Cl, or a perfluoroalkyl group;

k is an integer of 0 to 2;

l is 0 or 1;

n is an integer of 0 to 8, n Y¹s may be the same as or different from each other;

Y² is F or Cl;

m is an integer of 0 to 12, if m=0, l=0 and n=0, m Y²s may be the same as or different from each other;

A¹ is COOZ or SO₃Z, where Z is an alkali metal, an alkaline earth metal, hydrogen, or NR¹R²R³R⁴, where R¹, R², R³, and R⁴ are each a C1-C3 alkyl group or hydrogen; and

a repeating unit derived from tetrafluoroethylene.

4. The polymer electrolyte membrane according to claim 1,

wherein the polytetrafluoroethylene includes 0.011 mol % or more of a polymerized unit derived from the ethylenic comonomer in all the monomer units.

5. The polymer electrolyte membrane according to claim 1,

wherein the polytetrafluoroethylene includes 0.025 mol % or more of a polymerized unit derived from the ethylenic comonomer in all the monomer units.

6. The polymer electrolyte membrane according to claim 1,

wherein the ethylenic comonomer is perfluoro(methyl vinyl ether).

7. The polymer electrolyte membrane according to claim 1,

wherein the porous film has a product of vertical and lateral matrix tensile strengths of 2.20×

10⁴ MPa² or greater.

8. The polymer electrolyte membrane according to claim 1,

wherein the porous film has a contact angle with a solution of the polymer electrolyte of smaller than 50 degrees.

9. The polymer electrolyte membrane according to claim 1,

wherein the porous film has a film density of 1.4 g/cm³ or lower.

10. The polymer electrolyte membrane according to claim 1,

wherein the porous film has a thickness of smaller than 20 μ

m.

11. The polymer electrolyte membrane according to claim 1,

wherein the polytetrafluoroethylene has a standard specific gravity of 2.160 or lower.

12. A membrane electrode assembly comprising the polymer electrolyte membrane according to claim 1.

13. A polymer electrolyte fuel cell comprising the membrane electrode assembly according to claim 12.