Membranes and electrochemical cells incorporating such membranes

Abstract

One aspect of the invention provides an ion-conducting membrane comprising an ion-conducting region and a non-ion-conducting region. The ion-conducting region is formed by a plurality of ion-conducting passageways that extend through the membrane. The passageways are filled with ion-conducting material and may be surrounded by non-ion conducting material. The membrane may comprise a substrate of non-ion-conducting material that is penetrated by openings, each opening providing a corresponding one of the passageways.

1. A membrane comprising first and second major surfaces, the membrane comprising:
 a unitary  substrate comprising an ion-conducting region in which ions can pass through the substrate  and a non-ion-conducting region in which the ions cannot pass through the substrate ;  
 in the ion-conducting region, the substrate having one or more ion-conducting passageways that extend through the substrate;  
 the passageways containing an ion-conducting material that is relatively more ion-conductive than the non-ion-conducting region of the substrate;  
   wherein at least the first major surface of the membrane provides an ion - conducting region corresponding to the ion - conducting region of the substrate that is permeable to ions and at least the first major surface provides a non - ion - conducting region corresponding to the non - ion - conducting region of the substrate that is substantially impermeable to the ions.    
 
     
     
       2. A membrane according to  claim 1  wherein the ion-conducting region comprises a plurality of ion-conducting passageways. 
     
     
       3. A membrane according to  claim 2  wherein each passageway comprises a corresponding opening that penetrates the substrate and is filled with the ion-conducting material. 
     
     
       4. A membrane according to  claim 3  wherein the ion- conducting region of the  substrate is penetrated by a plurality of openings in a porous region of the substrate, the porous region of the substrate corresponding to the ion-conducting region of the membrane . 
     
     
       5. A membrane according to  claim 4  wherein the substrate comprises a  is substantially non-porous region corresponding to  in the  non - ion - conducting  region of the membrane  substrate. 
     
     
       6. A membrane according to  claim 5  wherein the porous  ion- conducting  region of the substrate is surrounded by the non-porous  non- ion - conducting  region of the substrate. 
     
     
       7. A membrane according to  claim 2  wherein each passageway has a maximum transverse dimension (D) that is less than or equal to about 2500 microns. 
     
     
       8. A membrane according to  claim 2  wherein a transverse center to center spacing between nearest neighboring passageways (L) is less than or equal to about 500 microns. 
     
     
       9. A membrane according to  claim 2  wherein a maximum transverse dimension (D) of each passageway and a transverse center to center spacing between nearest neighboring passageways (L) are selected such that a parameter ratio (L/D) that is less than or equal to about 2.5. 
     
     
       10. A membrane according to  claim 2  wherein each passageway has a transverse cross-sectional area less than or equal to about 1×10 −5  m 2 . 
     
     
       11. A membrane according to  claim 2  wherein a ratio of a total transverse cross-sectional area of the ion-conducting region to a total transverse cross-sectional area of the plurality of passageways (γ) is less than or equal to 2.5. 
     
     
       12. A membrane according to  claim 2  wherein a minimum transverse dimension of each passageway is greater than 25 microns. 
     
     
       13. A membrane according to  claim 2  wherein the passageways include passageways having transverse cross-sections that include at least one of: substantially circular, substantially hexagonal, substantially rectangular and substantially slit-shaped. 
     
     
       14. A membrane according to  claim 2  comprising a first skin layer of ion-conducting material located on a first side of the substrate, wherein the ion-conducting material of the first skin layer is in contact with the ion-conducting material of at least one of the passageways. 
     
     
       15. A membrane according to  claim 14  comprising a second skin layer of ion-conducting material located on a second side of the substrate, wherein the ion-conducting material of the second skin layer is in contact with the ion-conducting material of at least one of the passageways. 
     
     
       16. A membrane according to  claim 4  comprising a first skin layer of ion-conducting material, the first skin layer located on a first side of the substrate and extending transversely over at least a first portion of the porous  ion- conducting  region of the substrate such that the ion-conducting material of the first skin layer is in contact with the ion-conducting material of at least one of the passageways. 
     
     
       17. A membrane according to  claim 16  comprising a second skin layer of ion-conducting material, the second skin layer located on a second side of the substrate and extending transversely over at least a second portion of the porous  ion- conducting  region of the substrate such that the ion-conducting material of the second skin layer is in contact with the ion-conducting material of at least one of the passageways. 
     
     
       18. A membrane according to  claim 14  wherein the ion-conducting material in the first layer is the same as the ion-conducting material in the passageways. 
     
     
       19. A membrane according to  claim 14  wherein the ion-conducting material in the first skin layer is different from the ion-conducting material in the passageways. 
     
     
       20. A membrane according to  claim 14  wherein the ion-conducting material in the first skin layer is different than the ion-conducting material in the second layer. 
     
     
       21. An ion-conducting membrane comprising an ion-conducting region, the ion-conducting region comprising a substrate having one or more ion-conducting passageways that extend through the substrate, each passageway comprising an ion-conducting material that is relatively more ion-conductive than the substrate;
 the ion-conducting region comprising a plurality of ion-conducting passageways;  
 a first skin layer of ion-conducting material located on a first side of the substrate, wherein the ion-conducting material of the first skin layer is in contact with the ion-conducting material of at least one of the passageways;  
 a second skin layer of ion-conducting material located on a second side of the substrate; wherein the ion-conducting material of the second skin layer is in contact with the ion-conducting material of at least one of the passageways;  
 wherein the ion-conducting material in the first skin layer and the non-conducting material in a first portion of the passageways is different than the ion-conducting material in the second skin layer and a second portion of the passageways.  
 
     
     
       22. A membrane according to  claim 15  wherein the first and second skin layers have thickness (L skin ) that are substantially the same. 
     
     
       23. A membrane according to  claim 15  wherein the first and second skin layers have thicknesses (L skin1  and L skin2 ) that are in a range of 5-50 microns. 
     
     
       24. A membrane according to  claim 15  wherein the first and second skin layers each comprise the same ion-conducting material. 
     
     
       25. A membrane according to  claim 15  wherein the substrate has a thickness (L core ), the first and second skin layers have thicknesses (L skin1  and L skin2 ) and wherein a ratio of thicknesses (L skin1  and L skin2 ) of the first and second skin layers to the thickness (L core ) of the substrate is in a range of 0.25 to 5. 
     
     
       26. A membrane according to  claim 3  wherein the substrate comprises a plurality of layers. 
     
     
       27. A membrane according to  claim 24  wherein at least one of the plurality of layers of the substrate comprises a mesh material. 
     
     
       28. A membrane according to  claim 4  wherein the substrate is penetrated by one or more vias, the vias transversely spaced apart from the porous region of the substrate. 
     
     
       29. A membrane according to  claim 28  wherein the vias are filled with ion-conducting material. 
     
     
       30. A membrane according to  claim 29  wherein the ion-conducting material that fills the vias is contiguous with the ion-conducting material that fills the passageways. 
     
     
       31. A membrane according to  claim 1  comprising a plurality of ion-conducting regions, each ion-conducting region comprising one or more corresponding ion-conducting passageways that extend through the substrate, each ion-conducting passageway comprising the ion-conducting material. 
     
     
       32. A membrane according to  claim 31  wherein the ion-conducting regions are contiguous with one another. 
     
     
       33. A membrane according to  claim 31  wherein the ion-conducting regions are transversely spaced apart from one another. 
     
     
       34. A membrane according to  claim 31  wherein the one or more ion-conducting passageways corresponding to each ion-conducting region differ in at least one of: passageway size, passageway shape, passage density and/or arrangement of passageways. 
     
     
       35. An ion-conducting membrane comprising an ion-conducting region, the ion-conducting region comprising a substrate having one or more ion-conducting passageways that extend through the substrate; each passageway comprising an ion-conducting material that is relatively more ion-conductive than the substrate;
 the substrate comprising a sheet of substantially non-ion-conducting material;  
 wherein the passageways are formed by converting the substrate to a relatively more ion conductive state in selected locations corresponding to the passageways;  
 wherein the sheet of substantially non-ion-conducting material comprises a copolymer of tetrafluoroethylene ad perfluoro-3, 6-dioxa-4-methyl-7-octenesulfonyl fluoride.  
 
     
     
       36. A membrane according to  claim 2 , the substrate comprising a sheet of substantially non-ion-conducting material wherein the passage comprise a hydrolyzed form of the substantially non-ion-conducting material that is ion-conducting. 
     
     
       37. A membrane according to  claim 2  wherein the passageways and substrate are formed of a material having an ion-conducting form and a non-ion-conducting form wherein the passageway comprise the ion-conducting form of the material and the substrate surrounding the passages comprises the non-ion-conducting form of the material. 
     
     
       38. A membrane according to  claim 1  wherein the ion-conducting material comprises an ionomer. 
     
     
       39. A membrane having first and second major surfaces, the membrane comprising:
 a substrate comprising an ion-conducting region and a non-ion-conducting region;  
 the substrate penetrated by a plurality of openings in a porous  the ion- conducting  region thereof;  
 an ion-conducting material which fills the openings to provide a plurality of ion-conducting passageways through the substrate, the ion-conducting material being relatively more ion conductive than the non-ion-conducting region of the substrate  
 wherein the first and second major surfaces provide non- ion - conducting regions corresponding to the non - ion - conducting region of the substrate that are substantially impermeable to the ions.    
 
     
     
       40. A membrane having first and second major surfaces, the membrane comprising:
 a substrate comprising an ion-conducting region and a non-ion-conducting region; , the ion-  conducting region of    the  substrate penetrated by at least one opening;  
 an ion-conducting material which fills the at least one opening to provide an ion-conducting passageway through the substrate; and which provides  
 a first ion- conducting  skin layer on at least a first side of the substrate; the skin layer extending transversely past a perimeter of the at least one opening;  
 wherein the ion-conducting material is relatively more ion-conductive than the non-ion-conducting region of the substrate and at least the first major surface of the membrane has an ion- conducting region corresponding to the ion - conducting region of the substrate that is permeable to ions and the first and second major surfaces have non - ion - conducting regions corresponding to the non - ion - conducting region of the substrate that are substantially impermeable to the ions.    
 
     
     
       41. A membrane according to  claim 40  wherein the substrate is penetrated by one or more vias, the vias transversely spaced apart from the at least one opening and the vias filled with ion-conducting material that is contiguous with the ion-conducting material in the first skin layer. 
     
     
       42. A membrane according to  claim 41  comprising a second skin layer of ion-conducting material on a second side of the substrate, the ion-conducting material in the second skin layer contiguous with the ion-conducting material in the vias. 
     
     
       43. A membrane according to  claim 9  wherein the plurality of ion-conducting passageways are arranged to form an ordered array.. 
     
     
       44. A membrane according to  claim 6  wherein the plurality of openings each comprise a hole cleanly cut directly through the substrate.