Proton exchange membrane fuel cells
Disclosed embodiments concern a membrane electrode assembly or a proton exchange membrane fuel cell comprising a phosphoric acid-doped polymeric membrane comprising a cationic functional group, such as an assembly or fuel cell having an ion exchange capacity of 0.8 to 3 mmol/gram and an operating temperature range of from 80° C. to 220° C. The cationic functional group can be any suitable functional group, such as ammonium, imidazolium, guanidinium, phosphazenium, sulfonium, oxonium, and phosphonium, with working embodiments typically using quaternary ammonium cationic functional groups tethered to the polymeric core. The polymeric material may be any suitable polymeric material, such as a material selected from polyaryl polymers, polyarylamides, polyimides, polystyrenes, polysulfones, polyethers, polyether sulfones, polyketones, polyetherketones, polyarylethers, polyolefins, and polynitriles. The membrane electrode assembly or a proton exchange membrane fuel cell can be used in any application now known or hereafter developed, such as a vehicle or a stationary power device.
1. A membrane electrode assembly, comprising a phosphoric acid-doped polymeric membrane comprising a polymer comprising at least one functional group, wherein the polymer is selected from polyaryl polymers, polyarylamides, polyimides, polystyrenes, polysulfones, polyethers, polyether sulfones, polyketones, polyetherketones, polyarylethers, polyolefins, and polynitriles, and wherein the at least one functional group is a cationic functional group (CFG) that forms a cation-phosphate ion pair, the cationic functional group being selected from ammonium
imidazolium
guanidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently hydrogen, C 1-10 alkyl and benzyl.
2. The assembly according to claim 1 having an ion exchange capacity of 0.8 to 3 milliequivalents/g or 1.5 to 2.5 mmol/g and an operating temperature range of from 80° C. to a 220° C.
3. The assembly according to claim 1 wherein the polymer has a formula
[Polymer repeating unit] m -[Optional Linker] o -[Cationic Functional Group (CFG)] n
where m is two or more up to the number of monomeric subunits coupled to form a particular polymeric species; o is from 0 to at least m; and n is from 1 to at least o.
4. The assembly according to claim 3 wherein the polymer has a formula
CFG is a cationic group selected from ammonium
imidazolium
gaunidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently selected from hydrogen, aliphatic, aryl, and heteroaryl;
m is from two up to the number of monomeric subunits coupled to form a particular polymeric species;
p is from 1 to the number of possible positions available on the monomeric unit;
R 5 is a substituent selected from alkyl, alkenyl, alkynyl, alkoxy, alkylamino, alkylthio, acyl, aldehyde, amide, amino, aminoalkyl, aryl, arylalkyl, carboxyl, cyano, cycloalkyl, dialkylamino, halo, haloaliphatic, heteroaliphatic, heteroaryl, heterocycloaliphatic, hydroxyl, nitrile, oxo, sulfonamide, sulfhydryl, thioalkoxy, or other functionality;
r is 0 to 4; and
x is from 0 to 0.99.
5. The assembly according to claim 3 wherein the polymeric material has a formula
where:
CFG is a cationic group selected from ammonium
imidazolium
gaunidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently selected from hydrogen, aliphatic, aryl, and heteroaryl;
R 5 is a substituent selected from alkyl, alkenyl, alkynyl, alkoxy, alkylamino, alkylthio, acyl, aldehyde, amide, amino, aminoalkyl, aryl, arylalkyl, carboxyl, cyano, cycloalkyl, dialkylamino, halo, haloaliphatic, heteroaliphatic, heteroaryl, heterocycloaliphatic, hydroxyl, nitrile, oxo, sulfonamide, sulfhydryl, thioalkoxy, or other functionality; m is from two up to the number of monomeric subunits coupled to form a particular polymeric species;
R 6 and R 7 are independently selected from hydrogen, aliphatic, heteroaliphatic, aryl, heteroaryl, m is two or more up to the number of monomeric subunits coupled to form a particular polymeric species;
n is from 1 to at least m;
q is 1 to 10; and
r is from 0 to 4.
6. The assembly according to claim 3 wherein the polymeric material is a polyether sulfone having a formula
where:
CFG is a cationic group selected from ammonium
imidazolium
gaunidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently selected from hydrogen, aliphatic, aryl, and heteroaryl;
L is a linker;
R 5 is a substituent selected from alkyl, alkenyl, alkynyl, alkoxy, alkylamino, alkylthio, acyl, aldehyde, amide, amino, aminoalkyl, aryl, arylalkyl, carboxyl, cyano, cycloalkyl, dialkylamino, halo, haloaliphatic, heteroaliphatic, heteroaryl, heterocycloaliphatic, hydroxyl, nitrile, oxo, sulfonamide, sulfhydryl, thioalkoxy, or other functionality; m is from two up to the number of monomeric subunits coupled to form a particular polymeric species;
m is two or more up to the number of monomeric subunits coupled to form a particular polymeric species;
n is from 1 to at least m;
p is 1 to 5;
r is from 0 to 4; and
X is not present, or is selected from SO, SO 2 , CO, O, S,
where R 6 and R 7 are aliphatic, heteroaliphatic, aryl, or heteroaryl,
and combinations thereof.
7. The assembly according to claim 6 wherein X is
8. The assembly according to claim 6 wherein the polyether sulfone has a formula selected from
9. The assembly according to claim 3 wherein the polymeric material is a polyketone having a formula
or a polyetherketone having a formula
where:
CFG is a cationic group selected from ammonium
imidazolium
gaunidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently selected from hydrogen, aliphatic, aryl, and heteroaryl;
L is a linker;
R 5 is a substituent selected from alkyl, alkenyl, alkynyl, alkoxy, alkylamino, alkylthio, acyl, aldehyde, amide, amino, aminoalkyl, aryl, arylalkyl, carboxyl, cyano, cycloalkyl, dialkylamino, halo, haloaliphatic, heteroaliphatic, heteroaryl, heterocycloaliphatic, hydroxyl, nitrile, oxo, sulfonamide, sulfhydryl, thioalkoxy, or other functionality; m is from two up to the number of monomeric subunits coupled to form a particular polymeric species;
m is two or more up to the number of monomeric subunits coupled to form a particular polymeric species;
n is from 1 to at least m;
p is 1 to 5; and
r is from 0 to 4.
10. The assembly according to claim 3 wherein the polymeric membrane comprises a halogenated polyarylether or a nitrile-containing polyaryl ether having a formula
where:
CFG is a cationic group selected from ammonium
imidazolium
gaunidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently selected from hydrogen, aliphatic, aryl, and heteroaryl;
L is a linker;
R 5 is a halogen or nitrile;
m is two or more up to the number of monomeric subunits coupled to form a particular polymeric species;
n is from 1 to at least m;
p is from 1 to 5; and
r is from 0 to 4.
11. The assembly according to claim 10 wherein the polymeric material has a formula
12. The assembly according to claim 3 comprising a phosphoric acid doped polymeric membrane comprising a material having a formula
13. The assembly according to claim 1 wherein the polymer is crosslinked.
14. The assembly according to claim 1 comprising a quaternary ammonium tethered, phosphoric acid-doped polyaromatic polymer or a fluorinated or perfluorinated polymer.
15. A proton exchange membrane fuel cell comprising the assembly according to claim 1 .
16. A vehicle, comprising a proton exchange membrane fuel cell according to claim 15 .
17. A stationary power device comprising a proton exchange membrane fuel cell according to claim 15 .
18. A membrane electrode assembly comprising a phosphoric-acid doped polymeric membrane comprising a polyphenylene polymer having a formula
where m is 2 to 1000, n is at least 1 up to the number of total positions available on each monomeric unit, CFG is cationic functional group coupled to the polyphenylene core that forms a cation-phosphate ion pair and is selected from ammonium
imidazolium
guanidinium
phosphazenium
sulfonium
oxonium
and phosphonium
R 1 -R 4 are independently hydrogen, C 1 -C 10 alkyl and benzyl; L is a linker; and p is 1 to n.
19. The assembly according to claim 18 wherein the polymer has a structure
where q is from 1 to 10.
20. The assembly according to claim 18 wherein the linker is a C 1 -C 10 alkyl linker or an aryl linker.
21. A membrane electrode assembly, comprising:
a phosphoric acid-doped polymeric membrane comprising a polymer and at least one functional group for each monomeric unit of the polymer, wherein the polymer is selected from polyaryl polymers, polyarylamides, polyimides, polystyrenes, polysulfones, polyethers, polyether sulfones, polyketones, polyetherketones, polyarylethers, polyolefins, and polynitriles, and wherein the at least one functional group is a cationic functional group (CFG) that forms a cation-phosphate ion pair and is selected from ammonium
imidazolium
guanidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently hydrogen, C 1-10 alkyl and benzyl;
a phosphoric-acid-doped, cationic-functionalized ionomeric binder;
an anode catalyst layer;
a cathode catalyst layer; and
an electrocatalyst.
22. A membrane electrode assembly, comprising a phosphoric acid-doped polymeric membrane comprising a polymeric material comprising plural monomeric units and at least one functional group per monomeric unit, wherein the polymer is selected from polyaryl polymers, polyarylamides, polyimides, polystyrenes, polysulfones, polyethers, polyether sulfones, polyketones, polyetherketones, polyarylethers, polyolefins, and polynitriles, and wherein the at least one functional group is a cationic functional group (CFG) that forms a cation-phosphate ion pair and is selected from ammonium
imidazolium
guanidinium
phosphazenium
sulfonium
oxonium
and phosphonium
wherein R 1 -R 4 are independently hydrogen, C 1-10 alkyl and benzyl.