Polymer electrolyte film

Patent metadata

Field	Value
Publication number	US-2017005354-A1
Application number	US-201415100048-A
Country	US
Kind code	A1
Filing date	Dec 1, 2014
Priority date	Nov 29, 2013
Publication date	Jan 5, 2017
Grant date	—

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.

First claim

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 μm.

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 SO 3 Z group-containing monomer represented by the following formula (I):
CF 2 ═CF(CF 2 ) k —O 1 —(CF 2 CFY 1 —O) n —(CFY 2 ) m -A 1   (I)

wherein Y 1 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 Y 1 s may be the same as or different from each other; Y 2 is F or Cl; m is an integer of 0 to 12, if m=0, l=0 and n=0, m Y 2 s may be the same as or different from each other; A 1 is COOZ or SO 3 Z, where Z is an alkali metal, an alkaline earth metal, hydrogen, or NR 1 R 2 R 3 R 4 , where R 1 , R 2 , R 3 , and R 4 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 2.20×10 4 MPa 2 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/cm 3 or lower.

10 . The polymer electrolyte membrane according to claim 1 ,
wherein the porous film has a thickness of smaller than 20 μm.

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 .

Assignees

• Asahi Kasei E Materials Corp
• Daikin Ind Ltd

Inventors

• Inoue Yuichi
• Miyazaki Kuon
• Kikuchi Kentaro
• Uraoka Nobuki
• Chaen Shinichi
• Konishi Tomohisa
• Ino Tadashi

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• C08J2327/18

  Homopolymers or copolymers of tetrafluoroethylene · CPC title

• H01B1/122

  Ionic conductors · CPC title

• H01M8/1039 Primary

  halogenated, e.g. sulfonated polyvinylidene fluorides · CPC title

• B01D2323/42

  Details of membrane preparation apparatus · CPC title