Partially Quaternized Styrene-Based Copolymer, Ionic-Conductivity Imparter, Catalytic Electrode Layer, Membrane/Electrode Assembly and Process for Producing Same, Gas Diffusion Electrode and Process for Producing Same, and Fuel Cell of Anion Exchange Membrane Type

Patent metadata

Field	Value
Publication number	US-2017174800-A1
Application number	US-201515118133-A
Country	US
Kind code	A1
Filing date	Feb 3, 2015
Priority date	Feb 14, 2014
Publication date	Jun 22, 2017
Grant date	—

Abstract

A partially quaternized styrene-based polymer contains given amounts of a constituent unit having a quaternary salt type anion-exchange group and a constituent unit having a haloalkyl group. Due to the polymer, the ionic conductivity and the gas diffusion properties are kept high and the swelling of the electrode catalyst layer in a post-crosslinking step can be minimized to form a highly active catalytic electrode layer and obtain an excellent fuel-cell output.

First claim

1 . A partially quaternized styrene-based copolymer comprising:
a constituent unit comprising a quaternary base type anion-exchange group shown in below formula (1)

wherein “A” is hydrogen or methyl group, “a” is an integer of 1 to 8, R 1 and R 2 are methyl group or ethyl group, and R 3 is a linear alkyl group having a carbon atoms of 1 to 8, X − is one or two or more of counter ions selected from the group consisting of OH − , HCO 3 − , CO 3 2− , Cl − , Br − and I − , and
a constituent group comprising haloalkyl group shown in below formula (2)

wherein “A” is hydrogen or methyl group, “b” is an integer of 1 to 8, and “Y” is halogen atom and it is any one of Cl, Br, and I;
wherein a content ratio of the constituent unit shown in the formula (1) is 10 to 99 mass %, and a content ratio of the constituent unit shown in the formula (2) is 1 to 70 mass %.

2 . An ion-conductive additive comprising the partially quaternized styrene-based copolymer as set forth in claim 1 which is for a catalytic electrode layer used in an anion-exchange membrane type fuel cell.

3 . A catalytic electrode layer for an anion-exchange membrane type fuel cell, wherein the catalytic electrode layer comprising:
an electrode catalyst and an ion-conductive additive, wherein said ion-conductive additive comprises a constituent unit comprising a quaternary base type anion-exchange group shown in below formula (1)

wherein “A” is hydrogen or methyl group, “a” is an integer of 1 to 8, R 1 and R 2 are methyl group or ethyl group, and R 3 is a linear alkyl group having a carbon atoms of 1 to 8, X − is one or two or more of counter ions selected from the group consisting of OH − , HCO 3 − , CO 3 2− , Cl − , Br − and I − , and
a constituent unit comprising a crosslinking structure shown in below formula (3)

wherein “b” is an integer of 1 to 8, “c” is an integer of 2 to 8, R 4 , R 5 , R 6 and R 7 are selected from the group consisting of hydrogen, methyl group, and ethyl group, X − is one or two or more of counter ions selected from the group consisting of OH − , HCO 3 − , CO 3 2− , Cl − , Br − and I − ,
wherein a content ratio of the constituent unit shown in the formula (1) is 10 to 95 mass %, and a content ratio of the constituent unit shown in the formula (3) is 0.1 to 70 mass %; and
wherein said catalytic electrode layer for anion-exchange membrane type fuel cell is obtained by coating and drying a catalytic electrode forming composition comprising a catalyst and the ion-conductive additive as set forth in claim 2 , on an anion-exchange membrane, a precursor of the anion-exchange membrane or a gas diffusion layer to form a catalytic electrode precursor layer, then carrying out a quaternization and crosslinking reaction by contacting with a polyamine compound.

4 . A membrane-electrode assembly for the anion-exchange membrane type fuel cell comprising the catalytic electrode layer for the anion-exchange membrane type fuel cell as set forth in claim 3 .

5 . A gas diffusion electrode for the anion-exchange membrane type fuel cell comprising the catalytic electrode layer for the anion-exchange membrane type fuel cell as set forth in claim 3 .

6 . An anion-exchange membrane type fuel cell comprising the membrane-electrode assembly for the anion-exchange membrane type fuel cell as set forth in claim 4 .

7 . An anion-exchange membrane type fuel cell comprising the gas diffusion electrode for the anion-exchange membrane type fuel cell as set forth in claim 5 .

8 . A production method of a membrane-electrode assembly for an anion-exchange membrane type fuel cell comprising:
coating and drying a catalytic electrode forming composition comprising a catalyst and the ion-conductive additive for the catalytic electrode layer as set forth in claim 2 , on an anion-exchange membrane or a precursor of the anion-exchange membrane to form a catalytic electrode precursor layer, and then carrying out a quaternization and crosslinking reaction by contacting with a polyamine compound.

9 . A production method of a gas diffusion electrode for an anion-exchange membrane type fuel cell comprising:
coating and drying a catalytic electrode forming composition comprising a catalyst and the ion-conductive additive as set forth in claim 2 , on a gas diffusion layer to form a catalytic electrode precursor layer, and then carrying out a quaternization and crosslinking reaction by contacting with a polyamine compound.

Assignees

• Tokuyama Corp

Inventors

• Isomura Takenori
• Matsumura Yasunori
• Hanasaki Taichi

Classifications

• H01M4/8807

  Gas diffusion layers · CPC title

• H01M4/8828

  Coating with slurry or ink · CPC title

• C08F12/34

  Monomers containing two or more unsaturated aliphatic radicals · CPC title

• H01M4/8668

  Binders · CPC title

• H01M4/881

  Electrolytic membranes · CPC title