Proton conductive polymer electrolytes and fuel cells
View Patent ↗In one embodiment, a copolymer comprises a sulfonatable segment covalently linked to an un-sulfonatable segment through an organic linking group. The sulfonatable group segment may be sulfonated through direction sulfonation or sulfonation through a spacer molecule. In another embodiment, a copolymer comprises a sulfonated segment and an unsulfonated segment. A membrane electrode assembly and a fuel cell may be produced using the copolymer.
1. A polymer comprising polymer segments 1 and 2:
E 1 (SO 2 X) d -P 1 -Q 1 P 2 [1]
E 2 -P 3 -Q 2 -P 4 [2]
connected by a linking group L 1 to form polymer unit 3 and polymer unit 4:
E 2 -P 3 -Q 2 -P 4 j -L 1 E 1 (Z 1 ) d -P 1 -Q 1 -P 2 i [3]
E 2 -P 3 -Q 2 -P 4 j -L 1 E 1 (SO 2 X) d -P 1 -Q 1 -P 2 i [4]
wherein:
Z 1 is —SO 2 X, —PO 3 H 2 or —COX;
E 1 is an aromatic-containing moiety;
E 2 is an unsulfonated aromatic-containing and/or aliphatic-containing moiety;
L 1 is a linking group;
X is an —OH, a halogen, an ester, or
d is a number of Z 1 functional groups attached to E 1 ;
P 1 , P 2 , P 3 , P 4 are each independently absent, —O—, —S—, —SO—, —SO 2 —, —CO—, —NH—, NR 2 —, —R 3 —, and
R 2 is C 1-25 alkyl, C 1-25 aryl or C 1-25 arylene;
R 3 is C 1-25 alkylene, C 1-25 perfluoroalkylene, or C 1-25 arylene;
R 4 is trifluoromethyl, C 1-25 alkyl, C 1-25 perfluoroalkylene, C 1-25 aryl, or another E 1 group;
Q 1 , Q 2 are each independently a fluorinated cyclobutyl moiety;
i is a number representing repetition of polymer segment 1; and,
j is a number representing repetition of a polymer segment 2.
2. The polymer of claim 1 wherein Q 1 and Q 2 are each independently a perfluorocyclobutyl moiety.
3. The polymer of claim 1 wherein Q 1 and Q 2 are each independently:
4. The polymer of claim 1 wherein polymer unit 3 is repeated to form the following polymer unit:
L 2 E 2 -P 3 -Q 2 -P 4 j -L 1 E 1 -P 1 -Q 1 -P 2 ) i k
where L 2 is absent or a linking group and k is an integer representing repetition of the polymer unit 3.
5. The polymer of claim 4 wherein L 1 and L 2 each independently comprise an ether, imide, amide, ester, amine, ketone or acyl groups.
6. The polymer of claim 4 wherein L 1 and L 2 each independently comprise a chemical structure represented by one of the following formulae:
7. The polymer of claim 1 wherein E 1 and E 2 each independently comprises a structural unit represented by one of the following formulas:
8. The polymer of claim 1 wherein E 2 comprises a structural unit represented by one of the following formulas:
O—CF 7 —O, where R is an acyl group.
9. The polymer of claim 1 having the following formula:
10. The polymer of claim 1 wherein the Z i group is present at about 1 meq/g or greater.
11. The polymer of claim 1 wherein E 1 comprises at least one phenyl or phenylene group to which Z 1 is directly attached.
12. The polymer of claim 1 wherein E 1 (Z 1 ) d comprises a structure unit represented by one of the following formulae:
where n is a positive integer.