Membrane structure
A membrane, suitable for use in a fuel cell comprises: (a) a central region comprising an ion-conducting polymeric material; (b) a border region which creates a frame around the central region and which consists of one or more non-ion-conducting materials wherein at least one of the one or more non-ion-conducting materials forms a layer; wherein the non-ion-conducting material of the border region overlaps the ion-conducting polymeric material of the central region by 0 to 10 mm in an overlap region.
1. A membrane, suitable for use in a fuel cell, wherein the membrane comprises:
(a) a central region comprising an ion-conducting polymeric material; and
(b) a border region which creates a frame around the central region and which consists of one or more non-ion-conducting material wherein at least one of the one or more non-ion-conducting materials forms a layer,
wherein the non-ion-conducting material of the border region overlaps the ion-conducting polymeric material of the central region by 0 to 10 mm in an overlap region, and
wherein a single reinforcement extends throughout both the central and border regions of the membrane.
2. A membrane according to claim 1 , wherein the non-ion-conducting material of the border region overlaps the ion-conducting polymeric material of the central region on one face only.
3. A membrane according to claim 1 , wherein the non-ion-conducting material of the border region overlaps the ion-conducting polymeric material of the central region on both faces.
4. A catalyst-coated membrane comprising a membrane according to claim 1 and an electrocatalyst layer provided on one or both faces of the central region of the membrane.
5. A catalyst-coated membrane according to claim 4 , wherein the electrocatalyst layer extends into the overlap region by up to 10 mm.
6. A membrane electrode assembly comprising a catalyst-coated membrane according to claim 4 .
7. A fuel cell comprising a catalyst-coated membrane according to claim 4 .
8. A membrane electrode assembly comprising a membrane according to claim 1 .
9. A fuel cell comprising a membrane electrode assembly according to claim 8 .
10. A fuel cell comprising a membrane according to claim 1 .
11. The membrane according to claim 1 , wherein the non-ion-conducting material of the border region overlaps the ion-conducting polymeric material of the central region by 0 mm such that there is no overlap region.
12. The membrane according to claim 1 , wherein the ion-conducting polymeric material of the central region is a proton conducting polymer selected from the group consisting of perfluoroshulphonic acid ionomers, ionomers made from hydrocarbon polymers and phosphoric acid impregnated polybenzimidazole.
13. The membrane according to claim 1 , wherein the single reinforcement is formed from a polymer selected from the group consisting of fluoropolymer, polyvinylidene fluoride, PEEK, polyethylene and polyimide.
14. The membrane according to claim 1 , wherein the border region is formed from a polymeric material selected from the group consisting of thermoplastic polymers, thermoset polymers, cross-linked polymers, rubber, elastomers and thermoplastic elastomers.
15. The membrane according to claim 1 , wherein the border region is formed from three of more layers of non-ionic conducting material including an adhesive layer.
16. The membrane according to claim 1 , wherein the border region includes a gasket on one or both planar surfaces of the border region.
17. The membrane according to claim 1 , wherein the single reinforcement comprises a woven layer.
18. The membrane according to claim 1 , wherein the single reinforcement comprises a non-woven layer.
19. The membrane according to claim 1 , wherein the single reinforcement comprises a microporous layer.