ELECTROCHEMICAL OXYGEN PUMPS UTILIZING AN ANION CONDUCTING POLYMER

Abstract

An electrochemical oxygen pump moves or pumps oxygen molecules with a unique anion conducting layer comprising an anion conducting polymer. These pumps can either be used as high precision oxygen flow meters or as oxygen filters. The system can be plumbed to have air as the inlet and the pump will, selectively pump oxygen out, offering another way to remove oxygen from the air, along with distillation or pressure swing absorption.

Claims

1. An electrochemical oxygen pumping system comprising a) an electrochemical cell comprising: i) an anode on an anode side and having a film layer disposed thereon; ii) a cathode on a cathode side and having a film layer disposed thereon; iii) an anion conducting layer configured between said anode and cathode and comprising an anion conducting polymer; b) a power source coupled to the anode and cathode to provide an electrical potential across the anode and the cathode to initiate reaction of oxygen and water on the cathode to produce hydroxide that is transported across the anion conducting layer and reacted on the anode to produce oxygen and water, thereby pumping oxygen from the cathode side to the anode side.

2. The electrochemical oxygen pump system of claim 1, wherein the anion conducting polymer comprises quaternary ammonium functional groups.

3. The electrochemical oxygen pump system of claim 2, wherein the anion conducting polymer comprises a polyolefin backbone polymer.

4. The electrochemical oxygen pump system of claim 2, wherein the anion conducting polymer comprises a perfluoronated polyolefin backbone polymer.

5. The electrochemical oxygen pump system of claim 1, wherein the anion conducting polymer comprises a backbone polymer selected from the group consisting of: polyether ketone, polystyrene, polyolefins, perfluoronated polyolefin, polyphenolene oxide, or polybiphenyl alkylene.

6. The electrochemical oxygen pump system of claim 1, wherein the anion conducting polymer has functional groups selected from the group consisting of: imidazolium, pyridinium, or piperidine.

7. The electrochemical oxygen pump system of claim 1, where the film layer has the molecular structure M where M is selected from the group consisting of: platinum, silver, iridium, ruthenium, nickel, and cobalt.

8. The electrochemical oxygen pump system of claim 1, where the film layer has the molecular structure MO.sub.2 where M is selected from the group consisting of: platinum, silver, iridium, ruthenium, nickel, and cobalt.

9. The electrochemical oxygen pump system of claim 1 where the anode and cathode are made from a metallic material selected from the group consisting of: aluminum, 316 stainless, steel and titanium.

10. The electrochemical oxygen pump system of claim 9, wherein the anode and cathode are coated with gold or titanium nitride.

11. The electrochemical oxygen pump system of claim 1, wherein the electrode is coupled with a gas diffusion layer.

12. The electrochemical oxygen pump system of claim 1, further comprising flew fields coupled to the anode and the cathode.

13. The electrochemical oxygen pump system of claim 12, where the flow field is coated with gold or titanium nitride.

14. The electrochemical oxygen pump system of claim 1, wherein the anion conducting layer has a thickness of no more than 50 microns.

15. The electrochemical oxygen pump system of claim 1, wherein the ion conducting layer is an ultra-thin anion conducting layer having a thickness of no more than 20 microns and that passively transports water from the anode side to the cathode side.

16. The electrochemical oxygen pump system of claims 15, wherein the anion conducting layer comprises a support material.

17. The electrochemical oxygen pump system of claim 16, wherein the support material is a porous fluoropolymer membrane.

18. The electrochemical oxygen pump system of claim 17, wherein the porous fluoropolymer membrane comprises expanded polytetrafluoroethylene.

19. The electrochemical oxygen pump system of claims 17, wherein the anion conducting polymer is imbibed into the support material.

20. An electrochemical oxygen pumping system comprising: a) an electrochemical cell comprising: i) an anode on an anode side and having a film layer disposed thereon; ii) a cathode on a cathode side and having a film layer disposed thereon; iii) an anion conducting layer configured between said anode and cathode and comprising an anion conducting polymer comprising quaternary ammonium functional groups; b) a power source coupled to the anode and cathode to provide an electrical potential across the anode and the cathode to initiate reaction of oxygen and water on the cathode to produce hydroxide that is transported across the anion conducting layer and reacted on the anode to produce oxygen and water, thereby pumping oxygen from the cathode side to the anode side; wherein the ion conducting layer is an ultra-thin anion conducting layer having a thickness of no more than 20 microns and that passively transports water from the anode side to the cathode side; and wherein the anion conducting layer comprises a support material.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

[0029] FIG. 1 shows an exemplary electrochemical oxygen pump system comprising an electrochemical cell comprising a membrane electrode assembly.

[0030] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0031] As used herein, the terms comprises, comprising includes, including, has, having or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of a or an are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0032] Certain exemplary embodiments of the present invention are described herein. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations, and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.

[0033] Referring now to Equation 1, on the cathode side of the pump, the inlet oxygen and water combine with electrons to form hydroxide ions. These hydroxide ions then transport across the membrane to the anode side.

O.sub.2+2H.sub.2O+4e.sup.?.fwdarw.4OH.sup.? Equation 1. Half reaction the cathode.

[0034] Referring now to Equation 2, on the anode side, the hydroxide decomposes back into water and oxygen, completing the cycle, and giving the pump a Nerst potential of zero volts.

4OH.sup.?.fwdarw.O.sub.2+2H.sub.2O+4e.sup.? Equation 2. Half reaction at the anode.

[0035] As shown in FIG, 1, an exemplary environment control system 10, comprises an electrochemical oxygen pump system 14 that utilizes an electrochemical cell 12 comprising a membrane electrode assembly 30 connected to a circuit 31 for delivery of power from a power source 87. Oxygen and water from the cathode side 41 react on the cathode 40 to produce hydroxide ions, OH.sup.?. The hydroxide ions are transported across the ion conducting layer 28, an anion conducting layer 29, to the anode 20, wherein the hydroxides react to form oxygen and water on the anode side 21. A film layer 25, 45 is coupled to the anode and the cathode respectively. The cathode 40 is in fluid communication with the enclosure 50 and therefore reduces the oxygen concentration of the enclosure. The electrochemical cell also includes a gas diffusion layer 39, a flow field 38 and a current collector 33, configured on both the anode and cathode. The gas diffusion layer may comprise, consist essentially of or consist of carbon mesh, carbon paper, aluminum, copper, or titanium. The flow filed may comprise, consist essentially of or consist of 316 stainless steel, titanium, or aluminum 316 stainless steel, titanium, or aluminum.

[0036] The anion conducting layer may comprise, consist essentially of or consist of an anion conducting polymer having a backbone and wherein the backbone comprises at least one of: polyether ketone, polystyrene, polyolefins, perfluoronated polyolefin, polyphenolene oxide, or polybiphenyl alkylene. The anion conducting polymer has functional groups that may include quaternary ammonium, imidazolium, pyridinium, or piperidine. The anion conducting layer may consist essentially of the anion conducting polymer 73 or be a composite anion conducting layer and comprise a support material 74 and the anion conducting polymer 73. The anion conducting polymer may be imbibed into the support material, such as into the pores of the support material.

[0037] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any related or incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[0038] It will be apparent to those skilled in the art that various modifications, combinations, and variations can be made in the present invention without departing from the spirit or scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.