Liquid composition, polymer electrolyte membrane, membrane electrode assembly and polymer electrolyte fuel cell
To provide a liquid composition capable of forming a membrane excellent in durability against hydrogen peroxide or peroxide radicals and excellent in hydrogen gas barrier property; a polymer electrolyte membrane; a membrane electrode assembly; and a polymer electrolyte fuel cell. Liquid composition comprising a liquid medium, an acid-type sulfonic acid group-containing fluorocarbon polymer of which the hydrogen gas permeation coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10% is at most 2.5×10 −9 cm 3 ·cm/(s·cm 2 ·cmHg), and cerium atoms; a polymer electrolyte membrane 15 comprising the acid-type sulfonic acid group-containing fluorocarbon polymer, and cerium atoms; and a membrane electrode assembly 10 comprising an anode 13 having a catalyst layer, a cathode 14 having a catalyst layer, and the polymer electrolyte membrane 15 disposed between the anode 13 and the cathode 14.
1. A liquid composition comprising a liquid medium, an acid-type sulfonic acid group-containing fluorocarbon polymer comprising units represented by the following formula u1, and
cerium atoms:
where R F1 and R F2 are each independently a C 1-3 perfluoroalkylene group.
2. The liquid composition according to claim 1 , wherein a ratio of a total number of moles of the cerium atoms to a total number of moles of the sulfonic acid groups contained in the acid-type sulfonic acid group-containing fluorocarbon polymer, is from 0.001 to 0.13.
3. The liquid composition according to claim 1 , wherein an ion exchange capacity of the acid-type sulfonic acid group-containing fluorocarbon polymer is from 0.5 to 2.5 meq/g dry resin.
4. The liquid composition according to claim 1 , wherein a hydrogen gas permeation coefficient under conditions of a temperature of 80° C. and a relative humidity of 10% of the acid-type sulfonic acid group-containing fluorocarbon polymer comprising units represented by formula u1 is at most 2.5×10 −9 cm 3 ·cm/(s·cm 2 ·cmHg).
5. A polymer electrolyte membrane comprising an acid-type sulfonic acid group-containing fluorocarbon polymer comprising units represented by the following formula u1, and cerium atoms:
where R F1 and R F2 are each independently a C 1-3 perfluoroalkylene group.
6. The polymer electrolyte membrane according to claim 5 , wherein a ratio of the total number of moles of the cerium atoms to a total number of moles of the sulfonic acid groups contained in the acid-type sulfonic acid group-containing fluorocarbon polymer is from 0.001 to 0.13.
7. The polymer electrolyte membrane according to claim wherein an ion exchange capacity of the acid-type sulfonic acid group-containing fluorocarbon polymer is from 0.5 to 2.5 meq/g dry resin.
8. The polymer electrolyte membrane according to claim 5 , wherein a hydrogen gas permeation coefficient under conditions of a temperature of 80° C. and a relative humidity of 10% of the acid-type sulfonic acid group-containing fluorocarbon polymer comprising units represented by formula u1 is at most 2.5×10 −9 cm 3 ·cm/(s·cm 2 ·cmHg).
9. A membrane electrode assembly comprising an anode comprising a catalyst layer, a cathode comprising a catalyst layer, and the polymer electrolyte membrane as defined in claim 5 disposed between the anode and the cathode.
10. A polymer electrolyte fuel cell comprising the membrane electrode assembly as defined in claim 9 .
11. The liquid composition according to claim 1 , wherein:
a ratio of a total number of moles of the cerium atoms to a total number of moles of the sulfonic acid groups contained in the acid-type sulfonic acid group-containing fluorocarbon polymer, is from 0.001 to 0.13;
an ion exchange capacity of the acid-type sulfonic acid group-containing fluorocarbon polymer is from 0.5 to 2.5 meq/g dry resin;
a hydrogen gas permeation coefficient under conditions of a temperature of 80° C. and a relative humidity of 10% of the acid-type sulfonic acid group-containing fluorocarbon polymer comprising units represented by formula u1 is at least 1.0×10 −12 cm 3 ·cm/(s·cm 2 ·cmHg) and at most 2.5×10 −9 cm 3 ·cm/(s·cm 2 ·cmHg);
the liquid medium comprises an organic solvent and water wherein a proportion of the organic solvent is from 1 to 80 mass % and a proportion of the water is from 20 to 99 mass % based on a total of water and organic solvent; and
the acid-type sulfonic acid group-containing fluorocarbon polymer further comprises tetrafluroethylene units.
12. The liquid composition according to claim 1 , wherein R F1 and R F2 are each a C 1 perfluoroalkylene group.
13. The liquid composition according to claim 11 , wherein R F1 and R F2 are each a C 1 perfluoroalkylene group.
14. The polymer electrolyte membrane according to claim 5 , wherein:
a ratio of a total number of moles of the cerium atoms to a total number of moles of the sulfonic acid groups contained in the acid-type sulfonic acid group-containing fluorocarbon polymer, is from 0.001 to 0.13;
an on exchange capacity of the acid-type sulfonic acid group-containing fluorocarbon polymer is from 0.5 to 2.5 meq/g dry resin;
a hydrogen gas permeation coefficient under conditions of a temperature of 80° C. and a relative humidity of 10% of the acid-type sulfonic acid group-containing fluorocarbon polymer comprising units represented by formula u1 is at least 1.0×10 −12 cm 3 ·cm/(s·cm 2 ·cmHg) and at most 2.5×10 −9 cm 3 ·cm/(s·cm 2 ·cmHg); and
the acid-type sulfonic acid group-containing fluorocarbon polymer further comprises tetrafluroethylene units.
15. The polymer electrolyte membrane according to claim 5 , wherein R F1 and R F2 are each a C 1 perfluoroalkylene group.
16. The polymer electrolyte membrane according to claim 14 , wherein R F1 and R F2 are each a C 1 perfluoroalkylene group.
17. A membrane electrode assembly comprising an anode comprising a catalyst layer, a cathode comprising a catalyst layer, and the polymer electrolyte membrane as defined in claim 14 disposed between the anode and the cathode.
18. A polymer electrolyte fuel cell comprising the membrane electrode assembly as defined in claim 17 .