Highly stable fuel cell membranes and methods of making them
View Patent ↗A solid polymer electrolyte membrane having (a) an ion exchange material and (b) dispersed in said ion exchange material, a hydrogen peroxide decomposition catalyst bound to a carbon particle support, wherein the hydrogen peroxide decomposition catalyst comprises (i) polyvinylphosphonic acid and (ii) transition metal with multiple oxidation states or a lanthanide metal with multiple oxidation states.
1. A solid polymer electrolyte membrane comprising an (a) ion exchange material; (b) a peroxide decomposition catalyst bound to a support particle, wherein said peroxide decomposition catalyst comprises (i) an organic polymer comprising at least two carbon atoms and at least one moiety comprising phosphorous, and (ii) a metal comprising a transition metal with multiple oxidation states or a lanthanide metal with multiple oxidation states.
2. The solid polymer electrolyte membrane of claim 1 wherein said solid polymer electrolyte membrane further comprises expanded polytetrafluoroethylene.
3. The solid polymer electrolyte membrane of claim 1 wherein said peroxide decomposition catalyst is substantially insoluble in strong acid.
4. The solid polymer electrolyte membrane of claim 1 wherein said peroxide decomposition catalyst is a noncrystalline polymer.
5. The solid polymer electrolyte membrane of claim 1 wherein said support particle comprises alumina, silica, or zeolite.
6. The solid polymer electrolyte membrane of claim 1 wherein said support particle comprises carbon.
7. The solid polymer electrolyte membrane of claim 1 wherein said ion exchange material has an initial state in which it is dry ionomer, and said metal is present in an amount by weight of between 0.01% and 1% per dry ionomer.
8. The solid polymer electrolyte membrane of claim 1 wherein said ion exchange material has an initial state in which it is dry ionomer, and said metal is present in an amount by weight of about 0.2% per dry ionomer.
9. The solid polymer electrolyte membrane of claim 1 wherein said metal is cerium.
10. The solid polymer electrolyte membrane of claim 1 wherein said metal is manganese.
11. The solid polymer electrolyte membrane of claim 1 wherein said organic polymer is polyvinylphosphonic acid.
12. The solid polymer electrolyte membrane of claim 1 further comprising at least one expanded PTFE membrane having a porous microstructure of polymeric fibrils, and said ion exchange material impregnated throughout the porous microstructure of the expanded PTFE membrane so as to render an interior volume of the expanded PTFE membrane substantially occlusive.
13. The solid polymer electrolyte membrane of claim 12 wherein said solid polymer electrolyte membrane comprises a first layer of expanded PTFE having a porous microstructure of polymeric fibrils and said ion exchange material impregnated throughout the porous microstructure of the expanded PTFE membrane so as to render an interior volume of the expanded PTFE membrane substantially occlusive, and a second layer comprising ion exchange material.
14. The solid polymer electrolyte membrane of claim 13 wherein said peroxide decomposition catalyst is present in at least one of said layers.