Cylindrical electrolyzer for water electrolysis

Abstract

An electrolyzer cell including a first electrode having a first end and a second end, with a cylindrical sidewall extending along a longitudinal axis therebetween, the first end and the second end forming circular openings therethrough, a second electrode having a first circular end and a second circular end, defining a cylindrical length therebetween, the second electrode disposed concentrically within the first electrode, the cylindrical length extending along the longitudinal axis, a separator having a first end and a second end, having a cylindrical separator wall extending along a longitudinal axis therebetween, wherein the cylindrical separator is concentrically disposed within the sidewall of the first tubular electrode and circumferentially encloses the second rod electrode.

Description

[0001] CYLINDRICAL ELECTROLYZER FOR WATER ELECTROLYSIS

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 541,101, filed September 28, 2023, the entire contents of which are hereby incorporated by reference.

[0004] BACKGROUND OF THE DISCLOSED SUBJECT MATTER

[0005] Electrochemical or electrolysis cells generally comprise two flat electrodes (one cathode and one anode), a porous separator or ion-exchange membrane separating the two electrodes, current collector plates for anode and / or cathode sides with or without flow channels of different types, and sometimes, porous transport layers for anode and / or cathode sides. When water is electrolyzed in such cells, under suitable conditions, it can produce hydrogen gas, oxygen gas, and chlorine gas if seawater or brine water is used. The produced hydrogen gas can be used as fuels to generate electricity or to other devices such as fuel cells. Systems and methods for more efficiently electrolyzing water and aqueous solutions are needed.

[0006] SUMMARY OF THE DISCLOSED SUBJECT MATTER

[0007] The purpose and advantages of the disclosed subject matter will be set forth in and apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as from the appended drawings.

[0008] To achieve these and other advantages and in accordance with the purpose of the disclosed subject matter, as embodied and broadly described, the disclosed subject matter includes an electrolyzer cell including a first electrode having a first end and a second end, with a cylindrical sidewall extending along a longitudinal axis therebetween, the first end and the second end forming circular openings therethrough, a second electrode having a first circular end and a second circular end, defining a cylindrical length therebetween, the second electrode disposed concentrically within the first electrode, the cylindrical length extending along the longitudinal axis, a separator having a first end and a second end, having a cylindrical separator wall extending along a longitudinal axis therebetween, wherein the cylindrical separator is concentrically disposed within the sidewall of the first tubular electrode and circumferentially encloses the second rod electrode. The disclosed subject matter also includes a system for an electrolyzer cell, including a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, a first electrode having a first surface and a second surface parallel to the first surface, defining a planar thickness therebetween, the first electrode bisecting the tubular housing along the longitudinal axis and coupled to the inner surface, a second electrodes having a third and a fourth surface, each formed parallel to the first electrode, the second electrode extending along the longitudinal axis from the first end to the second end of the tubular housing, the second electrode spaced from the first surface along a lateral axis, a third electrode having a fifth and a sixth surface, each formed parallel to the first electrode, the third electrode extending along the longitudinal axis from the first end to the second end of the tubular housing, the third electrode spaced from the second surface along the lateral axis, a first separator having a first separator surface and a second separator surface parallel to the first separator surface, defining a planar thickness therebetween, the first separator coupled to the inner surface and extending along the longitudinal axis, the first separator disposed between the first electrode and the second electrode, a second separator having a third membrane surface and a fourth membrane surface parallel to the third membrane surface, defining a planar thickness therebetween, the second separator coupled to the inner surface and extending along the longitudinal axis, the first separator disposed between the first electrode and the third electrode.

[0009] An electrolyzer including a first electrode having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the first electrode forming a tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, a second electrode having a first surface and a second surface parallel to the first surface, defining a planar thickness therebetween, the first electrode bisecting the tubular housing along the longitudinal axis and coupled to the inner surface, a first and a second separator, each having a first separator surface and a second separator surface parallel to the first separator surface, defining a planar thickness therebetween, the first separator coupled to the inner surface and extending along the longitudinal axis, the first separator disposed between the first surface of the second electrode and the first electrode and the second separator disposed between the second surface of the second electrode and the first electrode.

[0010] The disclosed subject matter also includes a system for an electrolyzer cell, including a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, a hub extending along the longitudinal axis of the tubular housing from the first end to the second end, two first electrodes bisecting the tubular housing and extending from the first end to the second end radially extending from the hub, two second electrodes bisecting the tubular housing and the first electrodes, extending from the first end to the second end radially extending from the hub, the second electrodes angularly spaced from the first electrodes by 90 degrees and a separator disposed between each the first electrodes and the second electrodes, each separator angularly spaced from one another by 90 degrees.

[0011] The disclosed subject matter also includes a system for an electrolyzer cell, including a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, wherein the first end and the second end are at least partially open, a plurality of cell walls, each cell wall including a first electrode disposed within the tubular housing, the first electrode having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing, a second electrode disposed within the tubular housing, the second electrode having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing, wherein the second electrode is spaced from the first electrode and disposed parallel thereto, a separator disposed parallel and between the first electrode and the second electrode, the separator having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing and wherein each cell wall of the plurality of cell walls are disposed within the tubular housing at alternating angles.

[0012] The disclosed subject matter also includes a system for an electrolyzer cell, including a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, wherein the first end and the second end are at least partially open, a first electrode disposed helically within the tubular housing, the first electrode contacting the inner surface of the tubular housing, a second electrode disposed helically within the tubular housing, the second electrode contacting the inner surface of the tubular housing and spaced longitudinally from the first electrode, forming a spiral channel therebetween and a separator disposed helically within the spiral channel within the tubular housing, the separator contacting the inner surface of the tubular housing. It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the disclosed subject matter claimed.

[0013] The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the disclosed subject matter. Together with the description, the drawings serve to explain the principles of the disclosed subject matter.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A detailed description of various aspects, features, and embodiments of the subject matter described herein is provided with reference to the accompanying drawings, which are briefly described below. The drawings are illustrative and are not necessarily drawn to scale, with some components and features being exaggerated for clarity. The drawings illustrate various aspects and features of the present subject matter and may illustrate one or more embodiment(s) or example(s) of the present subject matter in whole or in part.

[0016] FIGS. 1A-1D are depictions of cylindrical electrolyzer for water electrolysis in accordance with the disclosed subject matter.

[0017] FIGS. 2A-2D are depictions of planar components within a tubular housing of a cylindrical electrolyzer for water electrolysis in accordance with the disclosed subject matter.

[0018] FIGS. 3A-3C are depictions of a radially-concentric cylindrical electrolyzer for water electrolysis in accordance with the disclosed subject matter.

[0019] FIGS. 4A-4C are depictions of alternating cell walls in a cylindrical electrolyzer for water electrolysis is accordance with the disclosed subject matter.

[0020] FIGS. 5A-5C are depictions of a helical cylindrical electrolyzer for water electrolysis in accordance with the disclosed subject matter.

[0021] DETAILED DESCRIPTION

[0022] Reference will now be made in detail to exemplary embodiments of the disclosed subject matter, an example of which is illustrated in the accompanying drawings. The method and corresponding steps of the disclosed subject matter will be described in conjunction with the detailed description of the system.

[0023] In various embodiments, the cylindrical electrolyzer may be configured for electrolyzing water to generate hydrogen and / or to desalinate water and / or to remove dissolved carbon dioxide from water and / or to produce certain products. In various embodiments, the systems and methods presented herein may be directed to a flow-through cylindrical eletrolyzer with both ends of the cell housing at least partially open. In such a flow-through cylindrical electrolyzer, the flow of feeding water can be powered by the kinetic energy of the water source, so that the pumping of feeding water can be avoided and the operation of such electrolyzer is more energy efficient.

[0024] In various embodiments, the systems and methods presented herein may be directed to cylindrical cell design which do not require bipolar plates and do not require precisely machined flow channels. In various embodiments, the systems and methods disclosed herein may utilize one or more bipolar plates or flow channels or may be configured to have bipolar plates therein. Such cylindrical cells may be more volumetrically efficient. In various embodiments, the cylindrical cells may be configured for compact design, thereby reducing costs.

[0025] As shown in FIGS. 1A-1D, the system 100 for the cylindrical electrolyzer cell is shown in a planform view, elevation view and a cross sectional view. Electrolyzer cell 100 includes a first electrode 104 having a first end and a second end, with a cylindrical sidewall extending along a longitudinal axis therebetween, the first end and the second end forming circular openings therethrough. Electrolyzer cell 100 includes a second electrode 108 having a first circular end and a second circular end, defining a cylindrical length therebetween, the second electrode disposed concentrically within the first electrode, the cylindrical length extending along the longitudinal axis. Electrolyzer cell 100 includes a separator 112 having a first end and a second end, having a cylindrical separator wall extending along a longitudinal axis therebetween. In various embodiments, the cylindrical separator 112 is concentrically disposed within the first electrode 104 and circumscribing the second electrode 108.

[0026] Electrolyzer cell 100 may have a pair of tubular electrodes 104 and 108, wherein one is an anode and one is a cathode. In various embodiments, one tubular electrode 104 and one rod electrode 112 inside of the tubular electrode 104. In certain embodiments, the anode comprises a spiral-wound coating. In certain such embodiments, the spiral-wound coating increases the active surface area of the anode. A cylindrical separator 112 may be placed between the two electrodes. In various embodiments, the separator 112 can be a porous film or a non-porous ion-exchange membrane. In various embodiments, the separator 112 can be a bipolar membrane. In various embodiments, electrolyzer cell 100 may or may not have an outer, cylindrical electrolyzer housing (not shown in the drawings). In various embodiments, the electrolyzer housing, electrodes 104, 108, and separators 112 are positioned concentrically. In various embodiments, the first and second ends of the electrolyzer cell 100 may be at least partially open. In various embodiments, the first and second ends may be configured as fully open orifices formed by the tubular first electrode 104. In various embodiments, the first and the second end may be formed with one or more openings therethrough. In various embodiments, the first and the second end may be formed with a plurality of openings therethrough. In various embodiments, feeding water is forced into this electrolyzer cell 100 by the kinetic energy of at least one water source. In various embodiments, the feed water may be forced through the first end and out of the second end of the electrolyzer cell 100. Therefore, no external pumping system and internal flow fields is required.

[0027] In various embodiments, the first electrode 104 is a cathode and the second electrode 108 is an anode. In various embodiments, the first electrode 104 is an anode and the second electrode 108 is a cathode. In various embodiments, the separator is a porous film. In various embodiments, the separator may be a non-porous ion-exchange membrane. In various embodiments, the separator may be a bipolar membrane. In various embodiments, the annular space between the first electrode 104 and the separator 112 may be greater than the annular space between the second electrode 108 and the separator 112. In various embodiments, the annular space between the first electrode 104 and the separator 112 may be lesser than the annular space between the second electrode 108 and the separator 112. In various embodiments, any of first electrode 104, second electrode 108 and separator 112 may be coupled via one or more internal bracing members, brackets, feed spacers or the like.

[0028] In various embodiments, first electrode 104 is a cathode electrode comprising Ni, Ti, a Ni-Al alloy, stainless steel, or a carbon-based material. In certain embodiments, the cathode comprises Ti. In some embodiments, the cathode comprises Ti and a coating comprising platinum (e.g., wherein the cathode comprises platinum-coated titanium). In certain embodiments, the cathode comprises nickel (Ni). In some embodiments, the cathode comprises a Ni-Al alloy, e.g. Raney nickel. In various embodiments, the cathode comprises stainless steel, e.g., a stainless steel type 304 mesh. In certain embodiments, the cathode comprises a carbonbased material, e.g. graphite, graphene, or glassy carbon. In certain preferred embodiments, the cathode is or comprises an electrocatalyst active in the production of hydrogen (H2) via the Hydrogen Evolution Reaction (HER). In various embodiments, said first electrode 104 acts as the housing of the electrolyzer cell 100. In various embodiments, the second electrode 108 is an anode electrode. In certain embodiments, the anode comprises a titanium (Ti) substrate. In certain such embodiments, the titanium substrate is coated with a coating layer. In further embodiments, the coating layer comprises at least one metallic element from group 4, group 5, group 6, group 7, group 8, group 9, group 10, group 11, group 12, group 13, or group 14. In yet further embodiments, the at least one metallic element is present as an oxide, sulfide, phosphate, or a combination thereof. In some embodiments, the at least one metallic element is present as a metal oxide. In certain embodiments, the at least one metallic element is selected from manganese, tin, tantalum, iridium, iron, palladium, platinum, or a combination thereof. In various embodiments, the anode comprises a noble metal coated on a titanium substrate, e.g., a titanium tube or rod. In certain preferred embodiments, the anode is or comprises an electrocatalyst active in the production of oxygen (O2) via the Oxygen Evolution Reaction (OER), which is selective for O2 production over CI2 production. In certain embodiments, separator 112 comprises an anion exchange membrane. In various embodiments, separator 112 may be a cylindrical Nafion 117 membrane disposed between the first and second electrodes. In certain embodiments, separator 112 is a filtration membrane. In certain preferred embodiments, separator 112 comprises a copolymer comprising at least one unit of first monomer and at least one unit of a second monomer, wherein the first monomer is, or is derived from, tetrafluoroethylene, and the second monomer is, or is derived from, sulfonated perfluorovinyl ether. In some embodiments, separator 112 comprises a sulfonated tetrafluoroethylene copolymer. In certain embodiments, separator 112 comprises, or is derived from, a compound having a CAS registry number 66796-30-3.

[0029] Referring now to FIGS. 2A-2C, an electrolyzer cell 200 is shown in a planform, perspective and orthogonal side views. Electrolyzer cell 200 has a pair or more of flat electrodes 208, 204, wherein at least one is an anode and at least one is a cathode, and a flat separator 216 between each pair of the anode and cathode electrodes 208, 212. In various embodiments, the separator 216 can be a porous film or a non-porous ion-exchange membrane. In various embodiments, the separator 216 can be one or more bipolar membranes. The electrodes 208, 212, and separators 216 are positioned in parallel inside a cylindrical electrolyzer housing 204. Both ends of the electrolyzer housing may be at least partially open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields is required.

[0030] In various embodiments, electrolyzer cell 200 includes a tubular housing 204 having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween. In various embodiments, tubular housing 204 has an inner surface and an outer surface, defining a cylindrical thickness therebetween. In various embodiments, first electrode 208 has a first planar surface and a second planar surface parallel to the first planar surface, defining a planar thickness therebetween. In various embodiments, first electrode 208 bisects the tubular housing 204 along the longitudinal axis and is coupled to the inner surface of the tubular housing 204.

[0031] In various embodiments, electrolyzer cell 200 includes second electrode 212 having a third and a fourth planar surface, each formed parallel to the first electrode 204, the second electrode 212 extending along the longitudinal axis from the first end to the second end of the tubular housing 204. In various embodiments, the second electrode 212 is spaced from the first surface along a lateral axis, the second electrode 212 disposed parallel to the first electrode 208. Second electrode 212 may form a chord of the tubular housing 204.

[0032] In various embodiments, electrolyzer cell 200 includes a third electrode 214 having a fifth and a sixth planar surface, each formed parallel to the first electrode 208, the third electrode 214 extending along the longitudinal axis from the first end to the second end of the tubular housing 204, the third electrode spaced from the second surface along the lateral axis. The third electrode 214 may be spaced along the lateral axis as a mirror image of the second electrode 212.

[0033] In various embodiments, electrolyzer cell 200 includes a first separator 216 having a first separator surface and a second separator surface parallel to the first separator surface, defining a planar thickness therebetween. The first separator 216 may be formed as a planar sheet or planar wall. The first separator 216 may be coupled to the inner surface of the tubular housing 204 and extends along the longitudinal axis, the first separator disposed between the first electrode 208 and the second electrode 212. In various embodiments, the second separator 218 may be spaced equidistant between the first electrode 208 and the second electrode 212. In various embodiments, the distance between the first electrode 208 and the second electrode 212 may be unequal.

[0034] In various embodiments, electrolyzer cell 200 includes a second separator 218 having a third membrane surface and a fourth membrane surface parallel to the third membrane surface, defining a planar thickness therebetween. In various embodiments, the second separator 218 may be coupled to the inner surface of the tubular housing 204 and extends along the longitudinal axis. In various embodiments, the second separator 218 may be disposed between the first electrode 208 and the third electrode 218. In various embodiments, the second separator 218 may be spaced equidistant between the first electrode 208 and the third electrode 214. In various embodiments, the distance between the first electrode 208 and the third electrode 214 may be unequal.

[0035] In various embodiments, the first and the second end may be formed with one or more openings therethrough. In various embodiments, the first and the second end may be formed with a plurality of openings therethrough. In various embodiments, feeding water is forced into this electrolyzer cell 200 by the kinetic energy of at least one water source. In various embodiments, the feed water may be forced through the first end and out of the second end of the electrolyzer cell 100. Therefore, no external pumping system and internal flow fields is required.

[0036] Referring to FIG. 2D, an electrolyzer 250 is shown in planform view. Electrolyzer cell 250 may have a flat electrodes 208, and a flat separator 216, 218 between the electrode 208 and the cylindrical electrode 251. The separators 216, 218 can be a porous film or a non-porous ion-exchange membrane. In various embodiments, the separators 216, 218 can be one or more bipolar membranes. The electrode 208 and separators 216, 218 are positioned in parallel inside a cylindrical electrode 251. Both ends of the electrolyzer may be at least partially open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields is required.

[0037] This electrolyzer 250 may have two cells. The outer cylindrical electrode 251 may be a cathode electrode for both cells. Cylindrical electrode 251 may be made of stainless steel and acts as the housing of the electrolyzer 250. The flat electrode 208 in the center is the anode electrode for both cells and may be made of transit metal catalysts coated on Ti mesh. The separators 216, 218 may be two flat Nafion 117 membranes placed between the anode and cathode electrodes. The anode electrode and the Nafion 117 membranes may be positioned in parallel inside the cylindrical electrode 208 (the cathode / housing). Both ends of the electrolyzer housing are open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields are required.

[0038] Referring now to FIGS. 3A-3C, an electrolyzer 300 is shown in a planform, perspective and orthogonal views. Electrolyzer cell 300 includes a tubular housing 304 having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween. In various embodiments, the tubular housing 304 has an inner surface and an outer surface, defining a cylindrical thickness therebetween. Electrolyzer cell 300 includes a first electrode 308 formed as a planar wall, the first electrode configured to bisect the tubular housing 308 along the longitudinal axis, extending from the first end to the second end.

[0039] Electrolyzer 300 includes a second electrode 312 bisecting the tubular housing 304 and the first electrode 308, extending along the longitudinal axis from the first end to the second end, the second electrode angularly spaced from the first electrode by 90 degrees. In various embodiments, the second electrode 312 may be angularly offset from the first electrode 308 by any angle, including an angle between approximately 1-90 degrees. In various embodiments, first electrode 308 may extend from a central hub 302 to the tubular housing 304. In various embodiments, the first electrode may be two distinct electrodes of the same type disposed coplanar within the tubular housing 304 on either side of hub 302. In various embodiments, first electrode 308 may extend the entire diameter of tubular housing 304. In various embodiments, the second electrode may be two distinct electrodes of the same type disposed coplanar with one another within the tubular housing 304 on either side of hub 302. In various embodiments, a first separator 316, or any separator may be disposed between the first electrode(s) 308 and the second electrode(s) 312. In various embodiments, the first separator 316 may be disposed equidistant between first electrode 308 and second electrode 312. In various embodiments, first separator 316 may extend from a central hub 302 to the tubular housing 304, extending the length of tubular housing 304. In various embodiments, first separator 316 may extend the interior diameter of tubular housing 304. In various embodiments, one or more of the first electrodes 308 and second electrodes 312 may include central slots for one or more other electrodes or membranes to angularly pass therethrough. Electrolyzer cell 300 includes a second separator 318 disposed between the first electrode 308 and the second electrode 312. In various embodiments, the second separator 318 may be angularly spaced from the first separator 316 by 90 degrees. In various embodiments, second separator 318 may extend from a central hub 302 to the tubular housing 304. In various embodiments, the second separator 318 may extend the distance across the tubular housing 304. In various embodiments, a separator may be disposed between any two first and second electrodes. For example and without limitation, the electrodes as shown in FIGS. 3A-3C may form four cells within the tubular housing 304, each cell defined by an adjacent first electrode 308 and second electrode 312. There may be one or more separators disposed within each cell between each first and second electrode pairs.

[0040] In various embodiments, electrolyzer 300 has a pair or more of flat electrodes 308, 312, wherein at least one is an anode and at least one is a cathode. Electrolyzer cell 300 may include aflat separator 316, 318 between each pair of anode and cathodes, and a cylindrical electrolyzer housing circumferentially encloses the radial configuration of the electrodes and separators. In various embodiments, the separators 316, 318 can be a porous film or a non-porous ionexchange membrane. In various embodiments, the separators 316, 318 can be one or more bipolar membranes. The electrodes and separators may be configured to intersect on the longitudinal axis of the cylindrical electrolyzer housing 304, for example at a hub 302. Both ends of the electrolyzer housing may be at least partially open, exposing the electrodes and separators to one or more fluid feeds. In various embodiments, the feeding water may be fed into this electrolyzer cell 300 by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields are required.

[0041] Electrolyzer 300 may have four cells, each separated by the radial electrodes / separators. The electrolyzer housing 304 may be an inert tubular housing. Separators 316, 318 may be two flat Nafion 117 membranes disposed between one flat anode and one flat cathode electrode. The anode electrodes may be made of precious metal catalysts coated on Ti plate, while the cathode electrodes may be made of stainless steel. The electrodes and separators intersect on the axis of the cylindrical electrolyzer housing 304, the electrodes and separators may meet a central hub 302 and couple thereto. Both ends of the electrolyzer housing are open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields are required.

[0042] Referring now to FIGS. 4A-4C, system 400 for an electrolyzer cell is shown in a planform, perspective and orthogonal views, respectively. System 400 includes at least one electrolyzer cell, which has one or multiple pairs of electrodes 408, 412, wherein at least one electrode is an anode and at least one is a cathode. System 400 includes a separator 416 between each pair of anode and cathode, and a cylindrical electrolyzer housing 404 circumferentially encloses the electrodes and separators. The separator 416 can be a porous film or a non-porous ion-exchange membrane. The electrodes 408, 412 and separators 416 may have a planform ellipse shape. In various embodiments, the electrodes 408, 412 and separators 416 may have the same ellipse planform shape. In various embodiments, the electrodes 408, 412 and separators 416 may have an ellipse planform shape, with varying semi major and semi minor axes, foci and eccentricities. The longitudinal axis of the cylindrical electrolyzer housing 404 may extend through the center of the ellipses at certain angle, such that the longitudinal axis is the central axis of the cylindrical housing, with the electrodes and separators disposed at a nonnormal angle to the longitudinal axis, the ellipses contacting the inner surface of the tubular housing at a non-normal angle. In various embodiments, each end of the electrolyzer housing 404 may be at least partially open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields is required.

[0043] With continued reference to FIGS. 4A-4C, system 400 includes an electrolyzer cell having a tubular housing 404 having a first end and a second end with a cylindrical sidewall extending along a longitudinal axis therebetween. The tubular housing 404 has an inner surface and an outer surface, defining a cylindrical thickness therebetween, wherein the first end and the second end are at least partially open. In various embodiments, the ends may be completely open circular openings defined by the tubular housing. In various embodiments, the first and second ends may have at least one opening formed therein. System 400 includes a plurality of cell walls 402, each cell wall including a first electrode 408 disposed within the tubular housing 404. The first electrode 412 may have an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing 404. System 400 includes a second electrode 412 disposed within the tubular housing 404, the second electrode 412 having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing 404, wherein the second electrode 412 is spaced from the first electrode 408 and disposed parallel thereto. As discussed herein, the elliptical perimeters may be the same shape or different.

[0044] System 400 includes a separator 416 disposed parallel and between the first electrode 408 and the second electrode 412, the separator 416 having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing 404. In various embodiments, the elliptical perimeter of the separator 416 may be the same as first electrode 408 and second electrode 412. In various embodiments, the elliptical perimeter may be different from first electrode 408. In various embodiments, each of the plurality of cell walls may be disposed within the tubular housing 404 at an alternating angle long the longitudinal axis. In various embodiments, the cell walls 402 may form a serpentine fluid path along the longitudinal axis of the tubular housing 404. In various embodiments, each cell wall 402 may be formed at a unique angle to the tubular housing 402. In various embodiments, each cell 402 may be formed at an equal and alternating angle, wherein each cell wall 402 is coupled to the tubular housing 404 at a common point with an adjacent cell wall 402.

[0045] In various embodiments, electrolyzer 400 may have six cells as shown in FIGS. 4B-4C. Housing 404 may be an inert cylindrical electrolyzer housing. Each cell may be formed from a reinforced perfluorosulfonic acid (PFSA) membrane (separator 416) between a pair of anode and cathode electrodes (408, 412). The anode electrodes may be made of precious metal catalysts coated on Ti mesh. The cathode electrodes may be Ni mesh. As described herein, electrodes 408, 412 and membranes / separators 416 may be an ellipse shape. The axis of the cylindrical electrolyzer housing 404 may intersect the center of the ellipses at 45° angles. In various embodiments, each end of the electrolyzer housing 404 are half open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields are required.

[0046] Referring now to FIGS. 5A-5C, electrolyzer cell 500 is shown in planform, elevation and orthogonal views, with and without the tubular housing. An electrolyzer cell 500 has one or more pairs of electrodes 508, 512, with at least one anode and at least one cathode. At least one separator 516 may be disposed between each pair of anode and cathode, circumferentially enclosed by tubular housing 504. In various embodiments, separator 516 can be a porous film or a non-porous ion-exchange membrane. In various embodiments, electrodes 508, 512 and separators 516 are helical and coaxial with the tubular housing 504. In various embodiments, at least one of the first end and the second end are at least partially open. In various embodiments, feeding water is forced into this electrolyzer cell by the kinetic energy of the water source through the first end and out of the second end. Therefore, no external pumping system and internal flow fields is required.

[0047] With continued reference to FIGS. 5A-5C, electrolyzer cell 500 includes a tubular housing 504 having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween. The tubular housing 504 has an inner surface and an outer surface, defining a cylindrical thickness therebetween, wherein the first end and the second end are at least partially open. Electrolyzer cell 500 includes a first electrode 508 disposed helically within the tubular housing 504, the first electrode 508 contacting the inner surface of the tubular housing 504 at the perimeter. In various embodiments, the helix formed by first electrode 508 may have a single pitch over the longitudinal length. In various embodiments, the first electrode 508 may have a varying pitch over the longitudinal length. In various embodiments, the first electrode 508 may have a variable pitch, such that it may be adjusted by one or more users.

[0048] Electrolyzer cell 500 includes a second electrode 512 disposed helically within the tubular housing 504, the second electrode 512 contacting the inner surface of the tubular housing 504 and spaced longitudinally from the first electrode 504, forming a spiral channel therebetween. In certain embodiments, the first and the second electrode 512 are each circular helices having a constant radius. In various embodiments, the first and the second electrode have an equal radius. In various embodiments, the helix formed by second electrode 512 may have a single pitch over the longitudinal length. In various embodiments, the second electrode 512 may have a varying pitch over the longitudinal length. In various embodiments, the second electrode 512 may have a variable pitch, such that it may be adjusted by one or more users. In various embodiments, second electrode 512 may be angularly offset from the first electrode 508 as to form the spiral channel therebetween with the same pitch as the first electrode 508. In various embodiments, first electrode 508 and second electrode 512 may include respective pitches configured to form larger portions of the spiral channel in some sections along the longitudinal length of the cell.

[0049] With continued reference to FIGS. 5A-5C, electrolyzer cell 500 includes a separator 516 disposed helically within the spiral channel within the tubular housing 504, separator 516 contacting the inner surface of the tubular housing 504. Separator 516 may be formed as a helix and be spaced longitudinally from the first electrode 508 and second electrode 512, disposed within the spiral channel. In various embodiments, the helix formed by separator 516 may have a single pitch over the longitudinal length. In various embodiments, the separator 516 may have a varying pitch over the longitudinal length. In various embodiments, the separator 516 may have a variable pitch, such that it may be adjusted by one or more users. In various embodiments, separator 516 may be angularly offset from the first electrode 508 and the second electrode 512 as to bisect the spiral channel therebetween with the same pitch as the electrodes 508, 512. In various embodiments, first electrode 508, second electrode 512 and separator 516 may include respective pitches configured to form larger portions of the spiral channel in some sections along the longitudinal length of the cell.

[0050] In various embodiments, electrolyzer 500 may have ten cells and an inert cylindrical electrolyzer housing 504. Each cell may have a porous Polyvinylidene fluoride (PVDF) separator between a pair of anode and cathode electrodes 508, 512. The anode electrodes may be formed from precious metal catalysts coated on Ti mesh. The cathode electrodes may be Ni mesh. The electrodes 508, 512 and separators 516 may be helical and coaxial with the cylindrical electrolyzer housing 504. Both ends of the electrolyzer housing may be half open. The feeding water is forced into this electrolyzer cell by the kinetic energy of the water source. Therefore, no external pumping system and internal flow fields are required.

[0051] In various embodiments, feeding water is forced into the electrolyzer cell 500 through the first end by at least one water source. In various embodiments, the feeding water is forced out of the electrolyzer cell 500 through the second end by the at least one water source. In various embodiments, the first electrode 508 is a cathode and the second electrode 512 is an anode. In various embodiments, the first electrode 508 is an anode and the second electrode 512 is a cathode. In various embodiments, the separator 516 is a porous film. In various embodiments, the separator 516 can be a non-porous ion-exchange membrane. In various embodiments, the separator 516 can be one or more bipolar membranes.

[0052] The terms “Nafion” and “Nafion 117”, as used herein, refer to a sulfonated tetrafluoroethylene copolymer comprising alternating, repeating subunits of tetrafluoroethylene and a sulfonated perfluorovinyl ether. Preferably, these terms refer to a copolymer having the CAS Registry Number 66796-30-3 and / or having the base chemical formula CVHFHCTS-CTF^

[0053] While the disclosed subject matter is described herein in terms of certain preferred embodiments, those skilled in the art will recognize that various modifications and improvements may be made to the disclosed subject matter without departing from the scope thereof. Moreover, although individual features of an embodiment of the disclosed subject matter may be discussed herein or shown in the drawings of the embodiment and not in other embodiments, it should be apparent that individual features of that embodiment may be combined with one or more features of another embodiment or features from a plurality of embodiments.

[0054] In addition to the specific embodiments claimed below, the disclosed subject matter is also directed to other embodiments having any other possible combination of the dependent features claimed below and those disclosed above. Thus, the particular features presented in the dependent claims and disclosed above can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter should be recognized as also specifically directed to other embodiments having any other possible combinations. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.

[0055] It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. An electrolyzer, comprising: a first electrode having a first end and a second end, with a cylindrical sidewall extending along a longitudinal axis therebetween, the first end and the second end forming circular openings therethrough; a second electrode having a first circular end and a second circular end, defining a cylindrical length therebetween, the second electrode disposed concentrically within the first electrode, the cylindrical length extending along the longitudinal axis; and a separator having a first end and a second end, having a cylindrical separator wall extending along a longitudinal axis therebetween, wherein the cylindrical separator is concentrically disposed within the sidewall of the first tubular electrode and circumferentially encloses the second rod electrode.

2. An electrolyzer, comprising: a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween; a first electrode having a first surface and a second surface parallel to the first surface, defining a planar thickness therebetween, the first electrode bisecting the tubular housing along the longitudinal axis and coupled to the inner surface; a second electrode having a third and a fourth surface, each formed parallel to the first electrode, the second electrode extending along the longitudinal axis from the first end to the second end of the tubular housing, the second electrode spaced from the first surface along a lateral axis; a third electrode having a fifth and a sixth surface, each formed parallel to the first electrode, the third electrode extending along the longitudinal axis from the first end to the second end of the tubular housing, the third electrode spaced from the second surface along the lateral axis; a first separator having a first separator surface and a second separator surface parallel to the first separator surface, defining a planar thickness therebetween, the first separator coupled to the inner surface and extending along the longitudinal axis, the first separator disposed between the first electrode and the second electrode; anda second separator having a third membrane surface and a fourth membrane surface parallel to the third membrane surface, defining a planar thickness therebetween, the second separator coupled to the inner surface and extending along the longitudinal axis, the second separator disposed between the first electrode and the third electrode.

3. An electrolyzer, comprising: a first electrode having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the first electrode forming a tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween; a second electrode having a first surface and a second surface parallel to the first surface, defining a planar thickness therebetween, the first electrode bisecting the tubular housing along the longitudinal axis and coupled to the inner surface; and a first and a second separator, each having a first separator surface and a second separator surface parallel to the first separator surface, defining a planar thickness therebetween, the first separator coupled to the inner surface and extending along the longitudinal axis, the first separator disposed between the first surface of the second electrode and the first electrode and the second separator disposed between the second surface of the second electrode and the first electrode.

4. An electrolyzer, comprising: a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween; a hub extending along the longitudinal axis of the tubular housing from the first end to the second end; two first electrodes bisecting the tubular housing and extending from the first end to the second end radially extending from the hub; two second electrode bisecting the tubular housing and the first electrodes, extending from the first end to the second end radially extending from the hub, the second electrodes angularly spaced from the first electrode by a first angle; and a separator disposed between each of the first electrodes and the second electrodes, each separator angularly spaced from one another by a second angle.

5. An electrolyzer, comprising: a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, wherein the first end and the second end are at least partially open; a plurality of cell walls, each cell wall comprising: a first electrode disposed within the tubular housing, the first electrode having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing; a second electrode disposed within the tubular housing, the second electrode having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing, wherein the second electrode is spaced from the first electrode and disposed parallel thereto; and a separator disposed parallel and between the first electrode and the second electrode, the separator having an elliptical perimeter, the elliptical perimeter contacting the inner surface of the tubular housing; wherein the cell walls of the plurality of cell walls are arranged within the tubular housing at alternating angles.

6. An electrolyzer, comprising: a tubular housing having a first end and a second end, having a cylindrical sidewall extending along a longitudinal axis therebetween, the tubular housing having an inner surface and an outer surface, defining a cylindrical thickness therebetween, wherein the first end and the second end are at least partially open; a first electrode disposed helically within the tubular housing, the first electrode contacting the inner surface of the tubular housing a second electrode disposed helically within the tubular housing, the second electrode contacting the inner surface of the tubular housing and spaced longitudinally from the first electrode, forming a spiral channel therebetween; and a separator disposed helically within the spiral channel within the tubular housing, the separator contacting the inner surface of the tubular housing.

7. The electrolyzer of any one of claims 1-6, wherein the first electrode is a cathode and the second electrode is an anode.

8. The electrolyzer of any one of claims 1-6, wherein the first electrode is an anode and the second electrode is a cathode.

9. The electrolyzer of claim 2, wherein the first electrode is an anode and the second and the third electrodes are cathodes.

10. The electrolyzer of claim 2, wherein the first electrode is a cathode and the second and the third electrodes are anodes.

11. The electrolyzer of any one of claims 1-10, wherein feeding water is fed into the electrolyzer cell through the first end by at least one water source.

12. The electrolyzer of any one of claims 1-11, wherein the feeding water exits the electrolyzer cell through the second end by the at least one water source.

13. The electrolyzer of any one of claims 1-12, wherein each separator is a porous film.

14. The electrolyzer of any one of claims 1-12, wherein the separator is a non-porous ionexchange membrane.

15. The electrolyzer of any one of claims 1-14, wherein the anode comprises a coating layer coated on a substrate.

16. The electrolyzer of any one of claims 1-15, wherein the cathode comprises nickel (Ni), stainless steel, or a carbon-based material.

17. The electrolyzer of any one of claims 1-16, wherein the separator is a filtration membrane.

18. The electrolyzer of any one of claims 1-17, wherein the separator comprises Nafion 117.

19. The electrolyzer of any one of claims 1-17, wherein the separator comprises a copolymer comprising at least one unit of first monomer and at least one unit of a second monomer, wherein the first monomer is, or is derived from, a tetrafluoroethylene (e.g., C2F4),and the second monomer is, or is derived from, a sulfonated perfluorovinyl ether (e.g., C7HFi3O5S).

20. The electrolyzer of claim 4, wherein at least one of the first angle and the second angle is 90 degrees.

21. The electrolyzer of claim 15, wherein the substrate is titanium (Ti).

22. The electrolyzer of claim 15 or 21, wherein the coating layer comprises at least one metallic element from group 4, group 5, group 6, group 7, group 8, group 9, group 10, group 11, group 12, group 13, or group 14.

23. The electrolyzer of claim 22, wherein the at least one metallic element is present as an oxide, sulfide, phosphate, or a combination thereof.

24. The electrolyzer of claim 23, wherein the at least one metallic element is present as a metal oxide.

25. The electrolyzer of any one of claims 22-24, wherein the at least one metallic element is selected from manganese, tin, tantalum, iridium, iron, palladium, platinum, or a combination thereof.

26. The electrolyzer of claim 15 or 21, wherein the anode comprises a noble metal coated on a titanium substrate.

27. The electrolyzer of any one of claims 15, and 21-26, wherein the anode is active towards O2 production in the Oxygen Reduction Reaction.

28. The electrolyzer of claim 16, wherein the cathode comprises stainless steel type 304.

29. The electrolyzer of claim 16 or 28, wherein the cathode is a stainless steel mesh.

30. The electrolyzer of claim 16, wherein the cathode comprises nickel and / or a Ni-Al alloy.

31. The electrolyzer of claim 16, wherein the cathode comprises a carbon-based material.

32. The electrolyzer of claim 31, wherein the carbon-based material is graphite, graphene, or glassy carbon.

33. The electrolyzer of any one of claims 1-15, wherein the cathode comprises titanium.

34. The electrolyzer of claim 33, wherein the cathode comprises a noble metal coated on a titanium substrate.

35. The electrolyzer of claim 34, wherein the cathode comprises platinum coated on a titanium substrate.

36. The electrolyzer of any one of claims 1-16 and 20-35, wherein the separator comprises an anion exchange membrane.

Images