Polymer electrolyte composition, polymer electrolyte membrane, membrane electrode assembly and solid polymer electrolyte-based fuel cell
The present invention provides a polymer electrolyte composition comprising a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g, a compound (B component) having a thioether group and a compound (C component) having an azole ring, wherein a mass ratio (B/C) of the B component to the C component is 1/99 to 99/1, and a total content of the B component and C component is 0.01 to 50% by mass based on the solid content in the polymer electrolyte composition.
1. A polymer electrolyte composition comprising:
a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g;
a compound (B component) having a thioether group; and
a compound (C component) having an azole ring, wherein a mass ratio (B/C) of the B component to the C component is 1/99 to 99/1 and a total content of the B component and C component is 0.01 to 50% by mass based on a solid content in the polymer electrolyte composition.
2. The polymer electrolyte composition according to claim 1 , wherein the content of the B component is 0.005 to 30% by mass and the content of the C component is 0.005 to 20% by mass based on the solid content in the polymer electrolyte composition.
3. The polymer electrolyte composition according to claim 1 or 2 , wherein the B component is a polyphenylene sulfide resin.
4. The polymer electrolyte composition according to claim 1 or 2 , wherein the C component is a polyazole-based compound.
5. The polymer electrolyte composition according to claim 1 or 2 , wherein the C component is one or two or more polyazole-based compounds selected from the group consisting of a polyimidazole-based compound, a polybenzimidazole-based compound, a polybenzobisimidazole-based compound, a polybenzoxazole-based compound, a polyoxazole-based compound, a polythiazole-based compound and a polybenzothiazole-based compound.
6. The polymer electrolyte composition according to claim 1 or 2 , wherein the C component is a polybenzimidazole-based compound.
7. The polymer electrolyte composition according to claim 1 or 2 , wherein the C component is poly[2,2′-(m-phenylene)-5,5′-bibenzimidazole].
8. The polymer electrolyte composition according to claim 1 or 2 , wherein the A component is a perfluorocarbon polymer compound having a structural unit represented by the following general formula [1];
—[CF 2 CX 1 CX 2 ] a —[CF 2 —CF((—O—CF 2 —CF—CF(CF 2 X 3 )) b —O c —(CFR 1 ) d —(CFR 2 ) e —(CF 2 ) f —X 4 )] g — [1]
(wherein each of X 1 , X 2 and X 3 is independently selected from the group consisting of a halogen atom and a perfluoroalkyl group having 1 to 3 carbon atoms,
X 4 represents COOZ, SO 3 Z, PO 3 Z 2 or PO 3 HZ (wherein Z represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or amines (NH 4 , NH 3 R 1 , NH 2 R 1 R 2 , NHR 1 R 2 R 3 , or NR 1 R 2 R 3 R 4 ), and each of R 1 , R 2 , R 3 and R 4 is independently selected from the group consisting of an alkyl group and an arene group; when X 4 represents PO 3 Z 2 , Z may be the same or different),
each of R 1 and R 2 is independently selected from the group consisting of a halogen atom, a perfluoroalkyl group or fluorochloroalkyl group having 1 to 10 carbon atoms,
a and g are positive numbers satisfying 0≦a<1, 0<g≦1 and a+g=1,
b is an integer of 0 to 8,
c is 0 or 1, and
each of d, e and f is independently an integer of 0 to 6 (with the proviso that d, e and f are simultaneously not 0)).
9. The polymer electrolyte composition according to claim 1 or 2 , further comprising a polyphenylene ether resin (D component) and/or an epoxy group-containing compound (E component), and wherein a mass ratio (D/E) of the D component to the E component is 0/100 to 100/0 and a total content of the D component and the E component is 0.01 to 20% by mass based on the solid content in the polymer electrolyte composition.
10. The polymer electrolyte composition according to claim 1 or 2 , wherein a resin comprising B component in a range from 50 to 100% by mass is dispersed in an island state and satisfies the following expression [2];
0%≦cumulative volume, volume basis, of resin having a particle diameter of 10 μm or more ≦5% [2].
11. The polymer electrolyte composition according to claim 10 , wherein the resin has an average particle diameter of from 0.01 to 2.0 μm.
12. The polymer electrolyte composition according to claim 10 , wherein the cumulative volume ratio (R1/R2) (volume basis) of a component (R1) having a particle diameter of less than 1 μm to a component (R2) having a particle diameter of 1 μm or more of the resin is 20/80 to 99/1.
13. A polymer electrolyte membrane formed from the polymer electrolyte composition according to claim 1 or 2 .
14. A process for producing a polymer electrolyte membrane, comprising the steps of:
dissolving or suspending a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g, a compound (B component) having a thioether group and a compound (C component) having an azole ring in one or more protic solvents to obtain a polymer electrolyte composition in which a mass ratio (B/C) of the B component to the C component is from 1/99 to 99/1 and a total of the content of the B component and the C component is from 0.01 to 50% by mass based on the solid content in the polymer electrolyte composition;
casting the polymer electrolyte composition; and
removing the solvents to form a membrane.
15. The process for producing the polymer electrolyte membrane according to claim 14 , comprising the steps of:
(1) mixing the B component into a polymer electrolyte precursor followed by melt extrusion to obtain a molded product;
(2) subjecting the molded product to hydrolysis treatment and further to acid treatment to convert the polymer electrolyte precursor into the A component;
(3) dissolving or suspending the acid-treated molded product in the one or more protic solvents to obtain a solution or suspension containing the A component and the B component;
(4) mixing together the solution or suspension obtained in the above step (3) and a solution or suspension of the C component to obtain the polymer electrolyte composition;
(5) casting the polymer electrolyte composition; and
(6) removing the solvents to form a membrane.
16. The process for producing the polymer electrolyte membrane according to claim 15 , wherein the step (1) further comprises mixing a polyphenylene ether resin (D component) and/or an epoxy group-containing compound (E component).
17. The process for producing the polymer electrolyte membrane according to claim 15 or 16 , further comprising filtering the solution or suspension obtained in the step (3).
18. A polymer electrolyte membrane obtained by the process according to any one of claims 14 to 16 .
19. The polymer electrolyte membrane according to claim 13 , further comprising a reinforcing material selected from the group consisting of an inorganic material, an organic material and an organic-inorganic hybrid material.
20. The polymer electrolyte membrane according to claim 19 , wherein the reinforcing material is a fibrous material.
21. The polymer electrolyte membrane according to claim 19 , wherein the reinforcing material is a continuous support.
22. A membrane electrode assembly comprising a polymer electrolyte membrane according to claim 13 .
23. An electrode catalyst layer produced from an electrode catalyst composition comprising:
a composite particle in which an electrode catalyst particle is supported on a conductive particle and
a polymer electrolyte composition comprising:
a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g,
a compound (B component) having a thioether group and
a compound (C component) having an azole ring,
wherein a content of the composite particle in the electrode catalyst layer is 20 to 95% by mass based on the electrode catalyst layer,
a mass ratio (B/C) of the B component to the C component is 1/99 to 99/1, and
a total content of the B component and the C component is 0.01 to 50% by mass based on the solid content in the polymer electrolyte composition.
24. The electrode catalyst layer according to claim 23 , wherein the B component is a polyphenylene sulfide resin.
25. The electrode catalyst layer according to claim 23 or 24 , wherein the C component is a polyazole-based compound.
26. The electrode catalyst layer according to claim 23 or 24 , wherein the C component is a polyazole salt.
27. The electrode catalyst layer according to claim 23 or 24 , wherein the C component is one or two or more polyazole-based compounds selected from the group consisting of a polyimidazole-based compound, a polybenzimidazole-based compound, a polybenzobisimidazole-based compound, a polybenzoxazole-based compound, a polyoxazole-based compound, a polythiazole-based compound and a polybenzothiazole-based compound.
28. The electrode catalyst layer according to claim 23 or 24 , wherein the C component is a polybenzimidazole-based compound.
29. The electrode catalyst layer according to claim 23 or 24 , wherein the C component is poly[2,2′-(m-phenylene)-5,5′-bibenzimidazole].
30. The electrode catalyst layer according to claim 23 or 24 , wherein the A component is a perfluorocarbon polymer compound having a structural unit represented by the following general formula [1];
—[CF 2 CX 1 CX 2 ] a —[CF 2 —CF((—O—CF 2 —CF—CF(CF 2 X 3 )) b —O c —(CFR 1 ) d —(CFR 2 ) e —(CF 2 ) f —X 4 )] g — [1]
(wherein each of X 1 , X 2 and X 3 is independently selected from the group consisting of a halogen atom and a perfluoroalkyl group having 1 to 3 carbon atoms,
X 4 represents COOZ, SO 3 Z, PO 3 Z 2 or PO 3 HZ (wherein Z represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or amines (NH 4 , NH 3 R 1 , NH 2 R 1 R 2 , NRH 1 R 2 R 3 , or NR 1 R 2 R 3 R 4 ), and
each of R 1 , R 2 , R 3 and R 4 is independently selected from the group consisting of an alkyl group and an arene group; when X 4 represents PO 3 Z 2 , Z may be the same or different),
each of R 1 and R 2 is independently selected from the group consisting of a halogen atom, a perfluoroalkyl group or fluorochloroalkyl group having 1 to 10 carbon atoms,
a and g are positive numbers satisfying 0≦a<1, 0<g≦1 and a+g=1,
b is an integer of 0 to 8,
c is 0 or 1, and
d, e and f are each independently an integer of 0 to 6 (with the proviso that d, e and f are simultaneously not 0)).
31. The electrode catalyst layer according to claim 23 or 24 , further comprising a polyphenylene ether resin (D component) and/or an epoxy group-containing compound (E component), and wherein a mass ratio (D/E) of the D component to the E component is 0/100 to 100/0, and a total content of the D component and the E component is 0.01 to 20% by mass based on the solid content in the polymer electrolyte composition.
32. A process for producing an electrode catalyst layer, comprising the steps of:
dissolving or suspending a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g, a compound (B component) having a thioether group and a compound (C component) having an azole ring in one or more protic solvents to obtain a polymer electrolyte composition in which a mass ratio (B/C) of the B component to the C component is 1/99 to 99/1 and a total content of the B component and the C component is 0.01 to 50% by mass based on the solid content in the polymer electrolyte composition;
preparing an electrode catalyst composition in which a composite particle where an electrode catalyst particle is supported on a conductive particle is dispersed in the polymer electrolyte composition at a ratio of from 1 to 100% by mass based on the polymer electrolyte composition; and
drying and solidifying the electrode catalyst composition.
33. An electrode catalyst layer obtained by the process according to claim 32 .
34. A polymer electrolyte solution or a polymer electrolyte suspension comprising a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g, a compound (B component) having a thioether group and a compound (C component) having an azole ring, wherein the A component, the B component and the C component are dissolved or suspended in one or more protic solvents, a mass ratio (B/C) of the B component to the C component is 1/99 to 99/1 and a total content of the B component and the C component is 0.01 to 50% by mass based on the solid contents in the polymer electrolyte solution or the polymer electrolyte suspension.
35. The polymer electrolyte solution or the polymer electrolyte suspension according to claim 34 , wherein a resin composed mainly of the B component having an average particle diameter of from 0.01 to 2.0 μm is dispersed.
36. The polymer electrolyte solution or polymer electrolyte suspension according to claim 34 or 35 , wherein the A component is a perfluorocarbon polymer compound having a structural unit represented by the following general formula [1];
—[CF 2 CX 1 CX 2 ] a —[CF 2 —CF((—O—CF 2 —CF—CF(CF 2 X 3 )) b —O c —(CFR 1 ) d —(CFR 2 ) e —(CF 2 ) f —X 4 )] g — [1]
(wherein each of X 1 , X 2 and X 3 is independently selected from the group consisting of a halogen atom and a perfluoroalkyl group having 1 to 3 carbon atoms,
X 4 represents COOZ, SO 3 Z, PO 3 Z 2 or PO 3 HZ (wherein Z represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or amines (NH 4 , NH 3 R 1 , NH 2 R 1 R 2 , NHR 1 R 2 R 3 , or NR 1 R 2 R 3 R 4 ), and each of R 1 , R 2 , R 3 and R 4 is independently selected from the group consisting of an alkyl group and an arene group; when X 4 represents PO 3 Z 2 , Z may be the same or different),
each of R 1 and R 2 is independently selected from the group consisting of a halogen atom, a perfluoroalkyl or fluorochloroalkyl group having 1 to 10 carbon atoms,
a and g are positive numbers satisfying 0≦a<1, 0<g≦1 and a+g=1,
b is an integer of 0 to 8,
c is 0 or 1, and
d, e and f are each independently an integer of 0 to 6 (with the proviso that d, e and f are simultaneously not 0)).
37. A membrane electrode assembly comprising the electrode catalyst layer according to claim 23 or 33 .
38. A membrane electrode assembly comprising
(a) a polymer electrolyte membrane formed from the polymer electrolyte composition according to claim 1 or 2 , and
(b) an electrode catalyst layer comprising:
a composite particle in which an electrode catalyst particle is supported on a conductive particle and
a polymer electrolyte composition comprising: a polymer electrolyte (A component) having an ion exchange capacity of from 0.5 to 3.0 meq/g, a compound (B component) having a thioether group and a compound (C component) having an azole ring,
wherein a content of the composite particle in the electrode catalyst layer is 20 to 95% by mass based on the electrode catalyst layer,
a mass ratio (B/C) of the B component to the C component is 1/99 to 99/1, and
a total content of the B component and the C component is 0.01 to 50% by mass based on the solid content in the polymer electrolyte composition.
39. A solid polymer electrolyte-based fuel cell comprising the membrane electrode assembly according to claim 22 .
40. A solid polymer electrolyte-based fuel cell comprising the membrane electrode assembly according to claim 37 .