PROTON CONDUCTING FILM HAVING CROSSLINKED STRUCTURE AND FUEL CELL

• US 20200136164A1
• Filed: 10/18/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Nagoya University, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Nagoya University, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: NAKAMURA, Naoki, NORO, Atsushi, KAJITA, Takato, TANAKA, Haruka, MATSUSHITA, Yushu
• Granted Patent: US 11,322,764 B2
• Time in Patent Office: Days
• CPC Class Codes: C08F 2438/03 Use of a di- or tri-thiocarbonylthio compound, e.g. di- or tri-thioester, di- or tri-thiocarbamate, or a xanthate as chain transfer agent, e.g . Reversible Addition Fragmentation chain Transfer [RAFT] or Macromolecular Design via Interchange of Xanthates [MADIX]
• CPC Class Codes: C08F 293/005 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 8/0221 Organic resins; Organic polymers
• CPC Class Codes: H01M 8/0239 Organic resins; Organic polymers
• CPC Class Codes: H01M 8/0258 characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
• CPC Class Codes: H01M 8/1018 Polymeric electrolyte materials
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A proton conducting film includes a polymer having a first part and a second part which are connected by a covalent bond and a plasticizer. The first parts aggregate with each other to form a domain at an operation temperature of the proton conducting film, and the second part crosslinks the domains. The second part has a proton accepting group, and the plasticizer contains a proton donating compound having a pKa of 2.5 or less, and thus the plasticizer penetrates into the second part, and a glass transition temperature of the polymer is lowered compared to when the plasticizer is not included.

Claims

1. A proton conducting film comprising:

a polymer having a first part and a second part which are connected by a covalent bond; and

a plasticizer,

wherein the first parts aggregate with each other to form a domain at an operation temperature of the proton conducting film, and the second part crosslinks the domains, and

the second part has a proton accepting group, and the plasticizer contains a proton donating compound having a pKa of 2.5 or less, and thus the plasticizer penetrates into the second part, and a glass transition temperature of the polymer is lowered compared to when the plasticizer is not included.

2. The proton conducting film according to claim 1, wherein

the domain is in a glass state or crystalline state.

3. The proton conducting film according to claim 1, wherein

the polymer is a block copolymer,

the first part is a block A of the block copolymer, and

the second part is a block B of the block copolymer.

4. The proton conducting film according to claim 1, wherein

a molar ratio of the proton donating compound to the proton accepting group is 1.0 or more and 10.0 or less.

5. The proton conducting film according to claim 1, wherein

the proton conducting film is a viscoelastic solid in a temperature range of 50°

C. or higher and 100°

C. or lower.

6. The proton conducting film according to claim 1, wherein

a content of the plasticizer is 50 parts by mass or more and 90 parts by mass or less with respect to a total of 100 parts by mass of the polymer and the plasticizer.

7. The proton conducting film according to claim 1, wherein

the proton donating compound is at least one selected from among sulfuric acid and phosphoric acid.

8. The proton conducting film according to claim 1, wherein

the proton accepting group is a nitrogen-containing heterocyclic group.

9. The proton conducting film according to claim 8, wherein

the nitrogen-containing heterocyclic group is a pyridine ring group or an imidazole ring group.

10. The proton conducting film according to claim 1, wherein

the first part is a polystyrene-based polymer.

11. The proton conducting film according to claim 3, wherein

the block copolymer is an A-B-A type triblock copolymer including the block A and the block B.

12. The proton conducting film according to claim 1, wherein

a film thickness of the proton conducting film is 1.00 mm or less.

13. The proton conducting film according to claim 1, wherein

a proton conductivity of the proton conducting film at 50°

C. is 10 mS/cm or more.

14. The proton conducting film according to claim 1, wherein

an ionic interaction occurs between free protons released from the proton donating compound, the proton donating compound which is anionized due to release of protons, and the proton accepting group which is cationized due to binding to the free protons.

15. A fuel cell comprising:

a fuel electrode side separator having a fuel flow path;

a fuel electrode side catalyst layer;

the proton conducting film according to claim 1;

an air electrode side catalyst layer; and

an air electrode side separator having an air flow path.