Rigid frame assemblies for co x electrolyzer stacks

Abstract

Assemblies for COx electrolysis are disclosed. Some implementations have a membrane electrode assembly ("MEA") having an MEA outer edge, a first rigid MEA support frame having a first body with a first annulus shape that extends around and defines a first opening, a first top surface having a first recess adjacent to the first opening, and extending around and radially outwards of the first opening, and a first bottom surface opposite the first top surface, a second rigid MEA support frame having a second body with a second annulus shape that extends around and defines a second opening, and a second bottom surface, and a first seal. The first rigid MEA support frame is connected to the second MEA support frame, the MEA is interposed between the first rigid MEA support frame and the second MEA support frame, and the MEA outer edge is positioned within the first recess.

Description

Docket No. OPUSP047WORIGID FRAME ASSEMBLIES FOR COXELECTROLYZER STACKSINCORPORATION BY REFERENCE

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.BACKGROUND

[0002] COXelectrolyzers offer a potential route for converting or reducing COXgas, e.g., CO or CO2, into one or more desired carbon-based byproducts, such as industrial chemicals or fuels, thereby allowing for waste COXgas that would normally be released into the atmosphere to instead be converted into industrially useful products.

[0003] Background and contextual descriptions contained herein are provided solely for the purpose of generally presenting the context of the disclosure. Much of this disclosure presents work of the inventors, and simply because such work is described in the background section or presented as context elsewhere herein does not mean that such work is admitted prior art.SUMMARY

[0004] Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims.

[0005] In some implementations, an assembly for COXelectrolysis may be provided that includes a membrane electrode assembly (“MEA”) having an MEA outer edge, a first rigid MEA support frame having a first body with a first annulus shape that extends around and defines a first opening, a first top surface having a first recess adjacent to the first opening, and extending around and radially outwards of the first opening, and a first bottom surface opposite the first top surface, a second rigid MEA support frame having a second body with a second annulus shape that extends around and defines a second opening, a second top surface, and a second bottom surface opposite the first top surface, and a first seal. The first top surface may face the second bottom surface, the first rigid MEA support frame may be connected to the second MEA support frame, the MEA may be interposed between the first rigid MEA supportDocket No. OPUSP047WOframe and the second MEA support frame, the MEA outer edge may be positioned within the first recess, and the first seal may extends around and be radially offset from the first opening and the second opening, may be interposed between the first rigid MEA support frame and the second MEA support frame, and may be in contact with the MEA.

[0006] In some implementations, the first seal may be in contact with the second bottom surface and interposed between the MEA and the second rigid MEA support frame.

[0007] In some such implementations, the assembly may further include a second seal that extends around and is radially offset from the first rectangular hole and the second rectangular hole, is in contact with the MEA and the first recess, and is interposed between the MEA and the first rigid MEA support frame.

[0008] In some implementations, the assembly may further include a third seal that extends around and is radially offset from the first recess, is interposed between the first rigid MEA support frame and the second MEA support frame, and is in contact with the first top surface and the second bottom surface.

[0009] In some implementations, the assembly may further include a cathode gas diffusion layer (GDL). The GDL may be interposed between the first rigid MEA support frame and the second MEA support frame, and the MEA may be in direct contact with the GDL.

[0010] In some such implementations, the GDL may have a GDL outer edge, and the MEA outer edge may be radially outwards of the GDL outer edge.

[0011] In some further such implementations, the first rigid MEA support frame may have a second recess adjacent to the first recess and the first opening, and extending around and radially outwards of the first opening, and the GDL outer edge may be positioned in the second recess.

[0012] In some further such implementations, the second rigid MEA support frame may have a second recess adjacent to the second opening, and extending around and radially outwards of the second opening, and the GDL outer edge may be positioned in the second recess.

[0013] In some implementations, the assembly may further include an anode porous transport layer (PTL). The PTL may be interposed between the first rigid MEA support frame and the second MEA support frame and the MEA may be in direct contact with the PTL.

[0014] In some such implementations, the PTL may have a PTL outer edge, and the MEA outer edge may be radially outwards of the PTL outer edge.

[0015] In some further such implementations, the first rigid MEA support frame may have a second recess adjacent to the first recess and the first opening, and extending around andDocket No. OPUSP047WOradially outwards of the first opening, and the PTL outer edge may be positioned in the second recess.

[0016] In some further such implementations, the second rigid MEA support frame may have a second recess adjacent to the second opening, and extending around and radially outwards of the second opening, and the PTL outer edge may be positioned in the second recess.

[0017] In some implementations, the assembly may further include a cathode gas diffusion layer (GDL) having a GDL outer edge, and an anode porous transport layer (PTL) having a PTL outer edge. The GDL and the PTL may be interposed between the first rigid MEA support frame and the second MEA support frame, the MEA may be interposed between the GDL and the PTL, and the MEA outer edge may be radially outwards of the GDL outer edge and PTL outer edge.

[0018] In some such implementations, the first rigid MEA support frame may have a second recess adjacent to the first recess and the first opening, and extending around and radially offset from the first opening, the second rigid MEA support frame may have a third recess adjacent to the second opening, and extending around and radially outwards of the second opening, the GDL outer edge may be positioned in the second recess, and the PTL outer edge may be positioned in the third recess.

[0019] In some such implementations, the first rigid MEA support frame may have a second recess adjacent to the first recess and the first opening, and extending around and radially offset from the first opening, the second rigid MEA support frame may have a third recess adjacent to the second opening, and extending around and radially outwards of the second opening, the PTL outer edge may be positioned in the second recess, and the GDL outer edge may be positioned in the third recess.

[0020] In some implementations, the assembly may further include a cathode frame, a cathode flow field at least partially disposed in a first opening in the cathode frame, an anode frame, and an anode flow field at least partially disposed in a second opening in the anode frame. The MEA, the first rigid MEA support frame, and the second MEA support frame may be interposed between the cathode frame and the anode frame, the MEA may have a cathodic part, an anodic part, and a separator between the cathodic part and the anodic part, the cathode frame may be adjacent to the cathodic part, the anode frame may be adjacent to the anodic part, and the cathode frame and the anode frame may be coupled to each other with a plurality of fasteners.

[0021] In some implementations, the assembly may further include an anode-cathode frame having a cathode flow field at least partially disposed in an opening in the anode-cathode frame,Docket No. OPUSP047WOand an anode flow field at least partially disposed in the opening. The anode-cathode frame may be adjacent to the first rigid MEA support frame or the second MEA support frame, the MEA may have a cathodic part, an anodic part, and a separator between the cathodic part and the anodic part, and the cathode flow field of the anode-cathode frame may be adjacent to the cathodic part of the MEA, or the anode flow field of the anode-cathode frame is adjacent to the anodic part of the MEA.

[0022] In some implementations, the first seal may be positioned in a groove of the first rigid MEA support frame or a groove of the second rigid MEA support frame.

[0023] In some implementations, the first seal may be an adhesive tape, screen printed, a dispensed seal, a sprayed seal, or a molded seal.

[0024] In some implementations, the first opening and second opening each may have a rectangular shape.

[0025] In some implementations, the first seal may have a cross-section that is circular, sawtooth, rectangular, obround, elliptical, trapezoidal, triangular, one or more semicircular portions, or a combination thereof.

[0026] The foregoing general description and the following detailed description are illustrative and explanatory and are intended to provide further explanation of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various embodiments disclosed herein are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements.

[0028] FIG. 1 depicts a diagram of an example MEA for use in COXreduction.

[0029] FIG. 2 shows a CO2 electrolyzer configured to receive water (H2O) and CO2.

[0030] FIG. 3 illustrates an example construction of a CO2 reduction MEA.

[0031] FIG. 4 illustrates an example construction of a CO reduction MEA.

[0032] FIG. 5 depicts an exploded view of an example multi-cell COx electrolyzer stack.

[0033] FIG. 6 depicts a perspective view of the example multi-cell COx electrolyzer of FIG.5.

[0034] FIG. 7 depicts an exploded view of an example repeat unit of the example multi-cell COx electrolyzer stack of FIG. 5.

[0035] FIG. 8 depicts an exploded view of an illustrative COXelectrolyzer cell of the example multi-cell COXelectrolyzer stack of FIG. 5.

[0036] FIG. 9 depicts an exploded view of an example cell for a multi-cell COx electrolyzer.Docket No. OPUSP047WO

[0037] FIG. 10 depicts an off-angle exploded view of an example assembly for COXelectrolysis.

[0038] FIG. 11 depicts an exploded cross-sectional side view slice of the assembly of FIG. 10.

[0039] FIG. 12 depicts the cross-sectional side view slice of the assembly of FIG. 11.

[0040] FIG. 13 depicts a magnified view of a portion of the assembly of FIG. 12.

[0041] FIG. 14 depicts a top view of the assembly of FIG. 10.

[0042] FIG. 15 depicts a cross-sectional side view slice of a portion of another assembly.

[0043] FIG. 16 depicts a cross-sectional side view slice of a portion of yet another assembly.

[0044] FIG. 17 depicts a cross-sectional side view slice of a portion of another assembly.

[0045] FIG. 18 depicts an exploded cross-sectional side view slice of a portion of yet another assembly.

[0046] FIG. 19 depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 18.

[0047] FIG. 20 depicts an exploded cross-sectional side view slice of a portion of another assembly.

[0048] FIG. 21 depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 20.

[0049] FIG. 22 depicts an exploded cross-sectional side view slice of a portion of yet another assembly.

[0050] FIG. 23 depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 22.

[0051] FIG. 24 depicts an exploded cross-sectional side view slice of a portion of another assembly.

[0052] FIG. 25 depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 24.

[0053] FIG. 26 depicts an exploded off-angle view of another assembly having an anode frame and a cathode frame.

[0054] FIG. 27 depicts an exploded cross-sectional side view slice of the assembly of FIG. 26.

[0055] FIG. 28 depicts a magnified cross-sectional slice of a portion of the assembly of FIG.27.

[0056] FIG. 29A depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 13.

[0057] FIG. 29B depicts a magnified cross-sectional side view slice of a portion of another assembly.Docket No. OPUSP047WO

[0058] FIG. 29C depicts a magnified cross-sectional side view slice of a portion of another assembly.

[0059] FIG. 29D depicts a magnified cross-sectional side view slice of a portion of another assembly.

[0060] FIG. 30 depicts a magnified cross-sectional side view slice of a portion of another assembly.DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0061] COx electrolyzers, e.g., CO2 electrolyzers, using membrane electrode assemblies may share some structural similarities with existing polymer electrolyte membrane (PEM) water electrolyzers, although there are several respects in which COXelectrolyzers may differ significantly from such PEM water electrolyzer systems.

[0062] In a typical COXelectrolyzer, a membrane electrode assembly (MEA) may be one of multiple elements that are stacked together in what may be referred to as a “cell”; in the discussion below, the term “cell” is used to refer to this multi-element assembly. As described below, many challenges exist in utilizing MEAs, such as challenges with handling MEAs and assembling MEAs together with other elements. Provided herein are new and novel rigid frame assemblies for MEAs used in COXelectrolyzers.Introduction and Context

[0063] An example MEA 100 for use in COXreduction is shown in FIG. 1. The MEA 100 has a cathode layer 120 and an anode layer 140 separated by an ion-conducting polymer layer 160 that provides a path for ions to travel between the cathode layer 120 and the anode layer 140. In certain embodiments, the cathode layer 120 includes an anion-conducting polymer and / or the anode layer 140 includes a cation-conducting polymer. In certain embodiments, the cathode layer 120 and / or the anode layer 140 of the MEA 100 are porous. The pores may facilitate gas and / or fluid transport and may increase the amount of catalyst surface area that is available for reaction.

[0064] The ion-conducting layer 160 may, for example, include two or three sublayers: a polymer electrolyte membrane (PEM) 165, an optional cathode buffer layer 125, and / or an optional anode buffer layer 145. One or more layers in the ion-conducting layer 160 may be porous. In certain embodiments, at least one layer is nonporous so that reactants and products of the cathode cannot pass via gas and / or liquid transport to the anode and vice versa. In certain embodiments, the PEM layer 165 is nonporous. Example characteristics of anode buffer layersDocket No. OPUSP047WOand cathode buffer layers are provided elsewhere herein. In some cases, the ion-conducting layer 160 includes only a single layer or two sublayers.

[0065] FIG. 2 shows CO2 electrolyzer 203 configured to receive water (H2O) and CO2 (e.g., humidified or dry gaseous CO2) as a reactant at a cathode 205 and expel CO as a product. Electrolyzer 203 is also configured to receive water as a reactant at an anode 207 and expel gaseous oxygen (O2). Although FIG. 2 depicts an electrolyzer configured to receive CO2 at the cathode and water at the anode, it should be understood that electrolyzers configured to receive other input feedstocks at the cathode and / or anode are contemplated in accordance with embodiments of the invention. For example, in some embodiments, an electrolyzer can be configured to receive carbon monoxide (CO) at the cathode and / or hydrogen (H2) at the anode. Electrolyzer 203 includes bipolar layers having an anion-conducting polymer 209 adjacent to cathode 205 and a cation-conducting polymer 211 (illustrated as a proton-exchange membrane) adjacent to anode 207.

[0066] As illustrated in the magnification inset of a bipolar interface 213 in electrolyzer 203, the cathode 205 includes an anion exchange polymer (which, in this example, is the same anion-conducting polymer 209 that is in the bipolar layers), electronically conducting carbon support particles 217, and metal nanoparticles 219 supported on the support particles. CO2 and water are transported via pores (such as pore 221) and reach metal nanoparticles 219 where they react, in this case with hydroxide (OH ) ions, to produce bicarbonate (HCO3) ions and reduction reaction products (not shown). CO2 may also reach metal nanoparticles 219 by transport within anion exchange polymer 209.

[0067] Hydrogen ions are transported from anode 207, and through the cation-conducting polymer 211, until they reach bipolar interface 213, where they are hindered from further transport toward the cathode 205 by anion exchange polymer 209. At interface 213, the hydrogen ions may react with bicarbonate or carbonate ions to produce carbonic acid (H2CO3), which may decompose to produce CO2 and water. As explained herein, the resulting CO2 may be provided in gas phase and may be provided with a route in the MEA back to the cathode 205 where it can be reduced. The cation-conducting polymer 211 hinders transport of anions, such as bicarbonate ions, to the anode 207 where they could react with protons and release CO2, which would be unavailable to participate in a reduction reaction at the cathode 205.

[0068] As illustrated, a cathode buffer layer having an anion-conducting polymer may work in concert with the cathode 205 and its anion-conductive polymer to block transport of protons to the cathode 205. While MEAs employing ion conducting polymers of appropriate conductivity types in the cathode 205 and cathode buffer layer may hinder transport of cations to the cathodeDocket No. OPUSP047WO205 and, if present, an anode buffer layer may similarly hinder transport of the anions to the anode 207, cations and anions may still come in contact in the MEA’s interior regions, such as in the membrane layer.

[0069] As illustrated in FIG. 2, bicarbonate and / or carbonate ions combine with hydrogen ions between the cathode layer and the anode layer to form carbonic acid, which may decompose to form gaseous CO2. It has been observed that MEAs sometimes delaminate, possibly due to this production of gaseous CO2, which does not have an easy egress path.

[0070] The delamination issue can be addressed by employing a cathode buffer layer having inert filler and associated pores. One possible explanation of its effectiveness is that the pores create paths for the gaseous carbon dioxide to escape back to the cathode 205 where it can be reduced. In some embodiments, the cathode buffer layer is porous, but at least one layer between the cathode layer and the anode layer is nonporous. This can prevent the passage of gases and / or bulk liquid between the cathode and anode layers while preventing delamination. For example, the nonporous layer can prevent the direct passage of water from the anode 207 to the cathode 205. The porosity of various layers in an MEA is described further at other locations herein.Examples of Bipolar MEAs

[0071] As an example, an MEA includes a cathode layer including a reduction catalyst and a first anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, or Tokuyama anion exchange polymer), an anode layer including an oxidation catalyst and a first cation-conducting polymer (e.g., PFSA polymer), a membrane layer including a second cation-conducting polymer and arranged between the cathode layer and the anode layer to conductively connect the cathode layer and the anode layer, and a cathode buffer layer including a second anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, or Tokuyama anion exchange polymer) and arranged between the cathode layer and the membrane layer to conductively connect the cathode layer and the membrane layer. In this example, the cathode buffer layer can have a porosity between about 1 and 90 percent by volume but can additionally or alternatively have any suitable porosity (including, e.g., no porosity). In other examples the cathode buffer layer can have any suitable porosity (e.g., between 0.01-95%, 0.1-95%, 0.01-75%, 1-95%, 1-90%, etc.).

[0072] Too much porosity can lower the ionic conductivity of the buffer layer. In some embodiments, the porosity is 20% or below, and in particular embodiments, between 0.1-20%, 1-10%, or 5-10%. Porosity in these ranges can be sufficient to allow movement of waterDocket No. OPUSP047WOand / or CO2 without losing ionic conductivity. Porosity may be measured as described further below.

[0073] In a related example, the MEA can include an anode buffer layer that includes a third cation-conducting polymer, and is arranged between the membrane layer and the anode layer to conductively connect the membrane layer and the anode layer. The anode buffer layer preferably has a porosity between about 1 and 90 percent by volume, but can additionally or alternatively have any suitable porosity (including, e.g., no porosity). However, in other arrangements and examples, the anode buffer layer can have any suitable porosity (e.g., between 0.01-95%, 0.1-95%, 0.01-75%, 1-95%, 1-90%). As with the cathode buffer layer, in some embodiments, the porosity is 20% or below, e.g. 0.1-20%, 1-10%, or 5-10%.

[0074] In an example, an anode buffer layer may be used in an MEA having a cathode catalyst layer with anion exchange polymer, a cathode buffer layer with anion-exchange polymer, a membrane with cation-exchange polymer, and an anode buffer layer with anion-exchange polymer. In such a structure, the anode buffer layer may be porous to facilitate water transport to the membrane / anode buffer layer interface. Water will be split at this interface to make protons that travel through the membrane and hydroxide that travels to the anode catalyst layer. In some cases, at least one catalyst (e.g., a carbon catalyst, a metal catalyst, etc.) may be utilized to promote the splitting of the water at this interface. For instance, the at least one catalyst may include a cobalt-based catalyst, an iron-nickel-based catalyst, a palladium-based catalyst, platinum-based catalyst, ruthenium (IV) dioxide (RuCE), nickel-stabilized, ruthenium dioxide (Ni-RuCE), iridium (IV) dioxide (IrCE), graphene, graphene oxide (GO), reduced graphene oxide (rGO), graphitic carbon nitride (g-CsN4), graphene quantum dots (GQDs), graphene quantum sheets (GQSs), and / or the like. One advantage of this structure is the potential use of low-cost water oxidation catalysts (e.g., NiFeOx) that are only stable in basic conditions.

[0075] In another specific example, the MEA includes a cathode layer including a reduction catalyst and a first anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, Tokuyama anion exchange polymer), an anode layer including an oxidation catalyst and a first cationconducting polymer, a membrane layer including a second anion-conducting polymer (e.g., Sustainion, FumaSep FAA-3, Tokuyama anion exchange polymer) and arranged between the cathode layer and the anode layer to conductively connect the cathode layer and the anode layer, and an anode buffer layer including a second cation-conducting polymer and arranged between the anode layer and the membrane layer to conductively connect the anode layer and the membrane layer.Docket No. OPUSP047WO

[0076] In an example, the MEA includes, consists of, or consists essentially of an anion-exchange polymer membrane and an anode buffer layer containing cation-exchange polymer. In this case, water can form at the membrane / anode buffer layer interface. Pores in the anode buffer layer could facilitate water removal. One advantage of this structure would be the use of an acid-stable (e.g., IrOx) water oxidation catalyst.

[0077] In a related example, the MEA can include a cathode buffer layer that includes a third anion-conducting polymer and is arranged between the cathode layer and the membrane layer to conductively connect the cathode layer and the membrane layer. The third anion-conducting polymer can be the same or different from the first and / or second anion-conducting polymer. The cathode buffer layer preferably has a porosity between about 1 and 90 percent by volume but can additionally or alternatively have any suitable porosity (including, e.g., no porosity). However, in other arrangements and examples, the cathode buffer layer can have any suitable porosity (e.g., between 0.01-95%, 0.1-95%, 0.01-75%, 1-95%, 1-90%). In some embodiments, the porosity is 20% or below, and in particular embodiments, between 0.1-20%, 1-10%, or 5-10%.

[0078] In an example, the cathode catalyst layer comprises, consists of, or consists essentially of metal catalyst particles (e.g., nanoparticles about 1 to about 5 nm in diameter, or about 4 nm in diameter) supported on carbon support particles and mixed with an anion-conducting polymer. In some embodiments, the metal catalyst particles comprise gold (Au), silver (Ag), copper (Cu), or combinations thereof. In a particular example, a cathode catalyst layer composed of Au nanoparticles 4nm in diameter supported on Vulcan XC72 or XC72R carbon and mixed with TM1 (mTPN-1) anion exchange polymer electrolyte may be used. The cathode catalyst layer may be about 15pm thick, have a gold to gold + carbon ratio by weight (Au / (Au+C)) of 20%, have a TM1 to catalyst mass ratio of 0.32, have mass loading of 1.4-1.6 mg / cm2(total Au+C), and have estimated porosity of 0.56. In another example, an anion-exchange polymer layer composed of TM1 and PTFE particles may be provided. The PTFE particles may be approximately 200 nm in diameter and the TM1 molecular weight may be approximately 30k-45k. The thickness of such an example anion-exchange polymer layer may be about 15 pm, and the PTFE particles may introduce a porosity of about 8%. A protonexchange membrane layer composed of perfluorosulfonic acid polymer (e.g., Nafion 115 or Nafion 117) may also be provided, with a thickness of approximately 100 pm to approximately 200 pm. The proton-exchange membrane may form a continuous layer that prevents significant movement of gas (CO2, CO, H2) through the layer. An anode catalyst layer composed of Ir or IrOxnanoparticles (100-200 nm aggregates) that is 10 pm thick may also be provided.Docket No. OPUSP047WOAnion Exchange Membrane-Only MEA for COXReduction

[0079] In some embodiments, an MEA does not contain a cation-conducting polymer layer. In such embodiments, the electrolyte is not a cation-conducting polymer and the anode, if it includes an ion-conducting polymer, does not contain a cation-conducting polymer. Various examples thereof are provided below.

[0080] An AEM-only MEA allows conduction of anions across the MEA. In embodiments in which none of the MEA layers has significant conductivity for cations, hydrogen ions have limited mobility in the MEA. In some implementations, an AEM-only membrane provides a neutral or an alkaline pH environment (e.g., at least about pH 7) and may facilitate CO2 and / or CO reduction by suppressing the hydrogen evolution parasitic reaction at the cathode. As with other MEA designs, the AEM-only MEA allows ions, notably anions such as hydroxide, bicarbonate, or carbonate ions, to move through polymer-electrolyte. The pH may be lower in some embodiments; a pH of 4 or greater may be sufficient to suppress hydrogen evolution. The AEM-only MEA also permits electrons to move to, and through, metal and carbon in catalyst layers. In embodiments, the AEM-only MEA may include pores in the anode layer, pores in the cathode layer, and / or pores in the PEM, thereby permitting liquids and gas to move through such pores.

[0081] In certain embodiments, the AEM-only MEA comprises an anion-exchange polymer electrolyte membrane positioned between a cathode and an anode. The cathode and the anode are each electrocatalyst layers. In some embodiments, one or both electrocatalyst layers also contain anion-exchange polymer-electrolyte.

[0082] In certain embodiments, an AEM-only MEA is formed by depositing cathode and anode electrocatalyst layers onto porous conductive supports, such as gas diffusion layers, porous transport layers, and / or the like, to form gas diffusion electrodes (GDEs). An anion-exchange membrane is then sandwiched between the gas diffusion electrodes.

[0083] In certain embodiments, an AEM-only MEA is used for CO2 reduction. The use of an anion-exchange polymer electrolyte avoids a low pH environment that disfavors CO2 reduction. Further, water is transported away from the cathode catalyst layer when an AEM is used, thereby preventing water build up (flooding) which can block reactant gas transport in the cathode of the cell.

[0084] Water transport in the MEA occurs through a variety of mechanisms, including diffusion and electro-osmotic drag. In some embodiments, at current densities of the CO2 electrolyzers described herein, electro-osmotic drag is the dominant mechanism. Water is dragged along with ions as they move through the polymer electrolyte. For a cation-exchangeDocket No. OPUSP047WOmembrane such as Nafion membrane, the amount of water transport is well characterized and understood to rely on the pre-treatment / hydration of the membrane. Protons move from positive to negative potential (anode to cathode) with each carrying 2-4 water molecules with it, depending on pretreatment.

[0085] FIG. 3 illustrates an example construction of a CO2 reduction MEA 301 having a cathode catalyst layer 303, an anode catalyst layer 307, and an anion-conducting PEM 305. In certain embodiments, cathode catalyst layer 303 may include metal catalyst particles (e.g., nanoparticles) that are unsupported or supported on a conductive substrate such as carbon particles. In some implementations, cathode catalyst layer 303 additionally includes an anion-conducting polymer. The metal catalyst particles may catalyze CO2 reduction, particularly at or within a non-acidic environment. In certain embodiments, anode catalyst layer 307 includes metal oxide catalyst particles (e.g., nanoparticles) that are unsupported or supported on a conductive substrate such as metal oxides, carbides, etc. In some implementations, the anode catalyst layer 307 may additionally include an anion-conducting polymer. Examples of metal oxide catalyst particles for anode catalyst layer 307 may include iridium oxide, nickel oxide, nickel iron oxide, iridium ruthenium oxide, platinum oxide, and the like. The anion-conducting PEM 305 may include any of various anion-conducting polymers such as, for example, HNN5 / HNN8 by lonomr, FumaSep by Fumatech, TM1 by Orion, PAP-TP by W7energy, Sustainion by Dioxide Materials, and the like. These and other anion-conducting polymers that have an ion exchange capacity (IEC) ranging from 1.1 to 2.6, working pH ranges from 0-14, limited solubility in some organic solvents, reasonable thermal stability and mechanical stability, good ionic conductivity / ASR, and acceptable water uptake / swelling ratio may be used. The polymers may be chemically exchanged to certain anions, such as bicarbonate, carbonate, etc., instead of halogen anions prior to use.

[0086] As illustrated in FIG. 3, CO2, such as CO2 gas, may be provided to cathode catalyst layer 303. In certain embodiments, the CO2 may be provided via a gas diffusion electrode. At the cathode catalyst layer 303, the CO2 reacts to produce a reduction product indicated generically as CxOyHz. Anions produced at the cathode catalyst layer 303 may include hydroxide, carbonate, and / or bicarbonate. These may diffuse, migrate, or otherwise move to the anode catalyst layer 307. At the anode catalyst layer 307, an oxidation reaction may occur such as oxidation of water or hydroxide ion to produce diatomic oxygen and hydrogen ions or water. In some applications, the hydrogen ions may react with hydroxide, carbonate, and / or bicarbonate to produce water, carbonic acid, and / or CO2. In some cases, fewer interfaces may provide lower resistance for the reaction(s) to occur. In some embodiments, a relatively highlyDocket No. OPUSP047WObasic environment (e.g., at least a pH above 7) is maintained for C2 and C3 hydrocarbon synthesis.

[0087] In certain embodiments, an AEM-only MEA may be employed in CO reduction reactions. Unlike the CO2 reduction reaction, CO reduction does not produce carbonate or bicarbonate anions that could transport to the anode and release valuable reactant.

[0088] FIG. 4 illustrates an example construction of a CO reduction MEA 401 having a cathode catalyst layer 403, an anode catalyst layer 407, and an anion-conducting PEM 405. Overall, the constructions of MEA 401 may be similar to that of MEA 301 in FIG. 3. However, the cathode catalyst may be chosen to promote a CO reduction reaction, which means that different reduction catalysts may be used in CO and CO2 reduction embodiments.

[0089] In some embodiments, an AEM-only MEA may be advantageous for CO reduction. The water uptake number of the AEM material can be selected to help regulate moisture at the catalyst interface, thereby improving CO availability to the catalyst. AEM-only membranes can be favorable for CO reduction due to this reason. Bipolar membranes can be more favorable for CO2 reduction due to better resistance to CO2 dissolving and crossover in basic anolyte media.

[0090] In various embodiments, cathode catalyst layer 403 may include metal catalyst particles (e.g., nanoparticles) that are unsupported or supported on a conductive substrate such as carbon particles. In some implementations, cathode catalyst layer 403 may additionally include an anion-conducting polymer. In certain embodiments, anode catalyst layer 407 includes metal oxide catalyst particles (e.g., nanoparticles) that are unsupported or supported on a conductive substrate such as metal oxides, carbides, etc. In some implementations, the anode catalyst layer 407 may additionally include an anion-conducting polymer. Examples of metal oxide catalyst particles for anode catalyst layer 407 may include those identified for the anode catalyst layer 307 of FIG. 3. Anion-conducting PEM 405 may include any of various anion-conducting polymers such as, for example, those identified for the PEM 305 of FIG. 3.

[0091] As illustrated in FIG. 4, CO gas may be provided to cathode catalyst layer 403. In certain embodiments, the CO may be provided via a gas diffusion electrode. At the cathode catalyst layer 403, the CO may react to produce a reduction product indicated generically as CxOyHz.

[0092] Anions produced at the cathode catalyst layer 403 may include hydroxide ions. These may diffuse, migrate, or otherwise move to the anode catalyst layer 407. At the anode catalyst layer 403, an oxidation reaction may occur such as oxidation of water or hydroxide ion toDocket No. OPUSP047WOproduce diatomic oxygen and hydrogen ions or water. In some applications, the hydrogen ions may react with hydroxide ions to produce water.

[0093] While the general configuration of the MEA 401 is similar to that of MEA 301, there are certain differences in the MEAs. For CO2 reduction, a significant amount of CO2 may be dissolved and then transferred to the anode for an AEM-only MEA such as shown in FIG. 3. For CO reduction, there is less likely to be significant CO gas crossover. In this case, the reaction environment for CO reduction could be more basic than the reaction environment for CO2 reduction. MEA materials, including the catalyst, may be selected to have good stability in high pH environments.Example of AEM-only MEA

[0094] 1. Copper metal (40 nm thick Cu, about 0.05 mg / cm2) was deposited onto a porous carbon sheet (Sigracet 39BC gas diffusion layer) via electron beam deposition. Ir metal nanoparticles were deposited onto a porous titanium sheet at a loading of 3 mg / cm2via drop casting or ultrasonic spray deposition. An anion-exchange membrane from lonomr (25-50 pm, 80 mS / cm2OH- conductivity, 2-3 mS / cm2HCOs’ conductivity, 33-37% water uptake) was sandwiched between the porous carbon and titanium sheets with the electrocatalyst layers facing the membrane.

[0095] 2. Sigma Aldrich 80 nm spherical Cu nanoparticles, mixed with FAA-3 anion exchange solid polymer electrolyte from Fumatech, FAA-3 to catalyst mass ratio of 0.10, setup as described above.

[0096] U.S. Patent Application Publication No. US 2017 / 0321334, published November 9, 2017, and U.S. Patent Application Publication No. 20190226103, published July 25, 2019, which describe various features and examples of MEAs, are incorporated herein by reference in their entireties. All publications referred to herein are incorporated by reference in their entireties as if fully set forth herein.Example Multi-cell COXElectrolyzer Stacks

[0097] Provided herein are MEA assemblies having rigid MEA support frames and the MEA. The MEA assemblies may be positioned in a repeat unit, a cell, or both. To provide further context, general aspects of repeat units and cells for COXelectrolyzer stacks are described herein.

[0098] FIG. 5 depicts an exploded view of an example multi-cell COXelectrolyzer stack. FIG.6 depicts a perspective view of the example multi-cell COXelectrolyzer of FIG. 5. As seen in FIGS. 5 and 6, multi-cell COXelectrolyzer stack (or stack) 500 includes a plurality of COXelectrolyzer cells (or cells), such as cell 501, formed by stacking a plurality of repeat units 503Docket No. OPUSP047WObetween cathode interface assembly 505 of cathode side assembly 507 and anode interface assembly 509 of anode side assembly 511.

[0099] The cathode side assembly 507 may include the cathode interface assembly 505, bus (or terminal) plate 513, manifold assembly 515, isolation plate 517, and end plate 519 sequentially stacked from a first side of the plurality of repeat units 503 in a first direction, e.g., an axial direction, which may extend parallel to the z-axis direction. Among other functions, the cathode side assembly 507 may at least be configured to provide one or more reactants to the cells to feed the COXreduction process and output one or more products from the cells in association therewith. The anode side assembly 511 may include the anode interface assembly 509, bus (or terminal) plate 521, isolation plate 523, and end plate 525 sequentially stacked from a second side of the plurality of repeat units 503 in a second direction opposite the first direction. Among other functions, the anode side assembly 511 may be at least configured to constrain axial expansion of the cells during the COXreduction process in a manner that prevents or reduces the likelihood of the plurality of cells from being overly compressed but which maintains corresponding fluidic seals and electrical conductivity between associated components of the stack 500.

[0100] The respective end plates 519 and 525 of the cathode side assembly 507 and the anode side assembly 511 may be coupled to one another via a plurality of biasing members 527 (e.g., anchors, bolts, studs, tie rods, etc.) extending in the axial direction and passing through corresponding holes in the end plates 519 and 525 and retained by nuts or other threaded fasteners. It is also noted that the end plates 519 and 525 may be formed of any suitable material, such as aluminum alloys, steel, magnesium alloys, titanium alloys, and / or the like. The biasing members 527 may be at least partially threaded to respectively engage with, for instance, threaded fasteners (e.g., nuts, rivets, etc.). In this manner, a clamping force extending in the axial direction may be applied to the plurality of cells via the conjunction of the end plates 519 and 525, the biasing members 527, and the threaded fasteners. Thus, the end plates 519 and 525 may generally serve to act as load- spreading members that act to distribute a clamping load relatively evenly over the other elements of stack 500. While the biasing members 527 are described as passing through the holes that may be defined in the end plates 519 and 525 and engaging with, for example, threaded fasteners to effect a clamping force, alternative arrangements are contemplated. For example, alternative arrangements of the biasing members 527 may include providing protrusions (e.g., pins) that extend outward from peripheral surfaces of the end plates 519 and 525 (e.g., in the X-Y plane), with the biasing members 527 engaging with one or more of these protrusions on each of the end plates 519 andDocket No. OPUSP047WO525. In such an example, one or more tensioning devices, e.g., turnbuckles, may be associated with each of the biasing members 527 such that the clamping force may be applied to the plurality of cells.

[0101] The bus plates 513 and 521 are respectively provided with terminal portions 513t and 52 It protruding outwardly from corresponding peripheral surfaces and may be respectively connected to a power supply. In some cases, the terminal portions 513t and 521t may have, for example, lugs, terminal blocks, or other electrical connection mechanisms to facilitate electrical connections between the bus plates 513 and 521 and a corresponding positive or negative voltage or current source. For example, the terminal portion 513t on a cathode side of stack 500 may be connected to a negative electrode of the power supply, and the terminal portion 52 It on an anode side of the stack 500 may be connected to a positive electrode of the power supply. In this manner, the bus plates 513 and 521 may provide common electrical connections for the plurality of cells of stack 500, such as the cell 501 and thereby enable an electrical potential or current to be generated across the plurality of cells of the stack 500 that may drive the reduction and oxidation reactions within the plurality of cells. For instance, when an electrical potential difference is imposed on the plurality of cells of the stack 500 through application of a voltage or current across the bus plates 513 and 521, the resulting electrical potential difference may cause an oxidation reaction at the anode sides of the cells (e.g., oxidation of water to molecular oxygen) and a reduction reaction at the cathode sides of the cells, e.g., that converts the COXinto carbon monoxide, a hydrocarbon, and / or other catalyst-specific products. As will become more apparent below, the bus plate 513 may be sized so as not to interfere with various fluidic passages through the stack 500.

[0102] According to various embodiments, bus plates 513 and 521 may be formed of a first electrically conductive material, e.g., aluminum alloys, iron, steel alloys, nickel alloys, lead, steel, zinc, and / or the like, that is coated (or plated) with a second, more electrically conductive coating, e.g., silver plating, gold plating, copper plating, or other material with relatively higher electrical conductivity, to provide a high level of electrical conductivity between the bus plates 513 and 521 and the corresponding flow fields (discussed later herein) of the cells of the stack 500.

[0103] The bus plate 513 may, for example, be electrically insulated from the end plate 519 by the isolation plate 517 and / or at least one other layer of electrically insulating material. As shown, the isolation plate 517 is disposed between the electrically conductive portion of the bus plate 513 and the end plate 519, and may include a plurality of fastener orifices through which the biasing members 527 may pass.Docket No. OPUSP047WO

[0104] Similar to the bus plate 513, the bus plate 521 may be electrically insulated from the end plate 525 by the isolation plate 523 and / or at least one other layer of electrically insulating material that may act in a similar manner as the isolation plate 517 with respect to the bus plate 513 and the end plate 519, but with respect to the end plate 525 and the bus plate 521. Similar to isolation plate 517, isolation plate 523 may include a plurality of fastener orifices through which biasing members 527 may pass.

[0105] The manifold assembly 515 may include manifold block (or main body) 541, first fluidic inlet connectors (or couplings) 543, first fluidic outlet connectors 545, second fluidic inlet connector 547, and second fluidic outlet connector 549. The first fluidic inlet connectors 543, for example, may supply fluid to the anode sides of the cells 501, while the first fluidic outlet connectors 545 may receive fluid from the anode sides of the cells 501. Similarly, the second fluidic inlet connector 547 may supply fluid to the cathode side of the cells 501 while the second fluidic outlet connector 549 may receive fluid from the cathode side of the cells 501.

[0106] The cells 501 of FIGS. 5 and 6 may generally each include a membrane electrode assembly (MEA) sandwiched between two or more gas-permeable layers which are, in turn sandwiched between an anode flow field and a cathode flow field. The MEAs describe and illustrated with respect to FIGS. 5 and 9 may be the MEA assemblies with rigid MEA support frames described herein. The anode flow field and the cathode flow fields may, for example, be housed within corresponding frames that may provide fluid feed-through passages that allow fluid supplied from the first fluidic inlet connectors 543 and the second fluidic inlet connector 547 to pass between the cells 501 and flow into the anode flow fields and cathode flow fields, respectively of the cells 501. The frames may also have additional feed-through passages that allow the fluid that flows out of the anode flow fields and the cathode flow fields to, for example, be routed to the first outlet connectors 545 and the second outlet connectors 549, respectively. Such fluid flow may occur while a voltage or current is applied across the terminal portions 513t and 521t, for example, such that an electrochemical reaction, e.g., a reduction reaction, involving the catalyst-containing layer occurs within each cell 501.COx Repeat Unit

[0107] FIG. 7 depicts an exploded view of an illustrative repeat unit of the example multi-cell COx electrolyzer stack of FIG. 5. Referring to FIG. 7, representative repeat unit (or repeat unit) 700 may include separator plate 707 at least partially stacked between anode components 701 and cathode components 703. Anode components 701 may include anode PTL 709, anode flow field 711, first anode gasket set 713, anode frame 715, and second anode gasket set 717.Docket No. OPUSP047WOIn some embodiments, anode components 701 may further include anode annular insert 718. Cathode components 703 may include the cathode GDL 721, and MEA assembly 719, as provided below (e.g., FIGS. 10 to 14), which has MEA 705 stacked between first and second rigid MEA support frames 723 and 725 along with a first seal 720, and may also include cathode flow field 727, first cathode gasket 729, cathode frame 731, and second cathode gasket 733. In some embodiments, cathode components 703 may further include cathode annular insert.

[0108] According to various embodiments, anode frame 715 may be coupled to cathode frame 731 via any suitable fastening mechanism(s), e.g., anchors, bolts, nuts, rivets, screws, and / or the like. For instance, anode frame 715 may be coupled to cathode frame 731 via swage (or press) nuts 735 pressed and / or clinched into anode frame 715 and fasteners 737 (e.g., shoulder screws), which interface with cathode frame 731 and extend through separator plate 707 to engage with swage nuts 735. In some embodiments, swage nuts 735 may be pressed and / or clinched into cathode frame 731 versus anode frame 715 such that fasteners 737 interface with anode frame 715 and extend through separator plate 707 to engage swage nuts 735 of cathode frame 731. It is also contemplated that a first some of swage nuts 735 may be pressed and / or clinched into anode frame 715 and a second some of swage nuts 735 may be pressed and / or clinched into cathode frame 731 such that a corresponding first some of fasteners 737 interface with cathode frame 731 and extend through separator plate 707 to engage with the first some of swage nuts 735 and a corresponding second some of fasteners 737 interface with anode frame 715 and extend through separator plate 707 to engage the second some of swage nuts 735 of cathode frame 731. Hereinafter, it will be assumed that swage nuts 735 are incorporated as part of anode frame 715 and fasteners 737 interface with cathode frame 731 and extend through separator plate 707 to engage swage nuts 735 of anode frame 715. In this manner, second anode gasket set 717 may be interposed between anode frame 715 and separator plate 707, whereas second cathode gasket 733 may be interposed between separator plate 707 and cathode frame 731.

[0109] According to various embodiments, when repeat unit 700 is assembled, anode flow field 711 may be supported in at least one opening in anode frame 715 such that a first surface of anode flow field 711 abuts against a corresponding surface of anode PTL 709 and a second surface of anode flow field 711 abuts against a corresponding surface of separator plate 707. In those instances when repeat unit 700 includes anode annular insert 718, anode annular insert 718 may be at least partially supported in at least one opening in anode frame 715 and may encircle anode flow field 711. To this end, at least a portion of first surface 718a (e.g., a topDocket No. OPUSP047WOsurface) of anode annular insert 718 may abut against one or more corresponding surfaces of a MEA assembly stacked between two adjacent repeat units or a MEA assembly of cathode interface assembly 505. At least a portion of second surface 718b (e.g., a bottom surface) of anode annular insert 718 opposing first surface 718a may abut against a corresponding surface of anode frame 715.

[0110] When repeat unit 700 is assembled, cathode flow field 727 may be supported in at least one opening in cathode frame 731 such that a first surface of cathode flow field 727 abuts against a corresponding surface of separator plate 707 and a second surface of cathode flow field 727 at least abuts against a corresponding surface of cathode GDL 721.COx Electrolyzer Cells

[0111] Referring to FIG. 8, an exploded view of cell 501 is shown. Cell 501 is formed between cathode components 703_l of repeat unit 503_l and anode components 701_2 of repeat unit 503_2. Separator plates 707_l and 707_2 of repeat units 503_l and 503_2 separate cell 501 from adjacent cells of stack 500. With this in mind, anode components 701_l of repeat unit 503_l and cathode components 703_2 of repeat unit 503_2 are shown in partially assembled states and form portions of such cells adjacent to cell 501. Hereinafter, components of cell 501 will be referenced followed by an underscore and identifier to indicate the repeat unit to which the components are a part without specifying the repeat unit itself.

[0112] Cell 501 may include an MEA 705_l interposed between anode porous transport layer (PTL) 709_2 and cathode GDL 721_1. The MEA 705_l is a part of MEA assembly 719_1 provided below (e.g., assembly 1000 in FIGS. 10 to 14) with the MEA 705_l and a first seal 720_l sandwiched between rigid MEA support frames 723_1 and 725_1, with the first seal 720_l in contact with the MEA 705_l. Support frames 723_1 and 725_1 may include respective openings, or holes, 723a_l and 725a_l exposing corresponding surfaces of the MEA 705_l . Anode PTL 709_2 may be interposed between MEA 705_l and anode flow field 711_2, whereas cathode GDL 721_1 may be interposed between MEA 705_l and cathode flow field 727_1. As such, opening 725a_l in support frame 725_1 may allow MEA 705_l and anode flow field 711_2 to be fluidically connected via anode PTL 711_2, and opening 723a_l in support frame 723_1 may allow MEA 705_l and cathode flow field 727_1 to be fluidically connected via cathode GDL 727_1.

[0113] Anode PTL 709_2 and anode flow field 711_2 may, for example, be supported in one or more openings in anode frame 715_2 and encircled by first anode gasket 713a_2 of first anode gasket set 713_2 at a first side of anode frame 715_2. Similarly, cathode flow field 727_1 and at least a portion of MEA assembly 719_1 (and, thereby, at least cathode GDLDocket No. OPUSP047WO721_1) may be supported in one or more openings of cathode frame 731_1 and encircled by first cathode gasket 729_1 at a first side of cathode frame 731_1. In turn, anode frame 715_2 may be stacked between the MEA assembly 719_1 and separator plate 707_2, and cathode frame 731_1 may be stacked between separator plate 707_l and the MEA assembly 719_1. Second anode gasket set 717_2 may be disposed between anode frame 715_2 and separator plate 707_2, whereas second cathode gasket 733_1 may be disposed between cathode frame 731_1 and separator plate 707_l. In this manner, first anode gasket 717a_2 of second anode gasket set 717_2 may encircle anode flow field 711_2 at a second side of anode frame 715_2, and second cathode gasket 733_1 may encircle cathode flow field 727_1 at a second side of cathode frame 731_1.

[0114] FIG. 9, for example, depicts an exploded view of another example electrolyzer cell assembly 902 (which is conceptually similar to the cells 501, although with a somewhat different form factor). In the example electrolyzer cell assembly 902, which may also be referred to as an electrolyzer cell assembly, has a membrane assembly 912 like that provided below (e.g., FIGS. 10 to 14) which may have a catalyst-containing membrane 914 that may be made of, for example, a polytetrafluoroethylene-based copolymer or a similar, suitable material that is then coated with catalyst(s). The membrane assembly 912, or MEA assembly like assembly 719, may have the first rigid MEA support frames 923 and 925, the catalystcontaining membrane 914, which may be considered the MEA, and a first seal 920 between the support frames 923 and 925 and in contact with the MEA. The catalyst-containing membrane 914 may, for example, have a region that is coated on one or both sides with one or more catalysts that may be selected so as to result in a desired COx reduction reaction taking place when COx gas is provided to the first fluidic inlet connectors 543 and water is provided to the second fluidic inlet connector 547 (referring back to FIGS. 5 and 6). Catalyst-containing membranes are typically relatively expensive materials — a square meter of Nafion™, which is produced by The Chemours Company and which is a commonly used membrane material for catalyst-containing membranes, can cost approximately $2,000 US.

[0115] The catalysts may take the form of metal catalyst particles (e.g., nanoparticles) that are unsupported or supported on a conductive substrate such as carbon particles. In certain embodiments, the cathode catalyst layer may include gold (Au) particles and the anode catalyst layer may include metal oxide catalyst particles such as iridium oxide, nickel oxide, nickel iron oxide, iridium ruthenium oxide, platinum oxide, or the like.

[0116] The cell assembly 902 may also include one or more porous layers 916, such as the porous layer 916a and the porous layer 916b. Each porous layer 916 may, in some cases, be,Docket No. OPUSP047WOfor example, a gas diffusion layer (GDL) or a porous transport layer (PTL). The porous layers may serve to permit fluids to be transported between the MEA and the flow fields, e.g., from the flow fields to the MEA or from the MEA to the flow fields. The fluids transported by the porous layers may, for example, include liquids and / or gases that may be delivered into the electrolyzer or generated within the MEA.

[0117] As can be seen in FIG. 9, the electrolyzer cell assembly 902 includes, in addition to the membrane assembly 912, various elements, including a separator plate 910 (a separator plate 910a and a separator plate 910b are shown, although one of these two separator plates 910a and 910b would actually be “part” of an adjacent electrolyzer cell assembly 902), two frames 904a and 904b, a first flow field 906, and a second flow field 908. The separator plates 910 may be made of an electrically conductive, high-strength material, such as a steel alloy, a titanium alloy, or other such materials, and may serve to act as part of the electrically conductive path that extends through the flow fields 906 and 908 and the membrane assemblies 912 of the electrolyzer cell assemblies 902 when such electrolyzer cell assemblies 902 are assembled into a stack, e.g., as shown in the example of FIGS. 5 and 6. The separator plates 910 may also serve a structural function, as they may act as a structural web that may connect with the frames 904 and reinforce the frames 904 against potentially displacing outward, e.g., when the fluids introduced into one or both of the flow fields 906 and 908 are introduced at relatively high fluidic pressures, e.g., hundreds of pounds per square inch. Such pressures may exert a significant outward load on the frames 904, causing them to bulge outward unless restrained, e.g., through being coupled to the separator plates 910.

[0118] The first flow field 906 and the second flow field 908 may each provide one or more flow paths that are recessed into the sides of the first flow field 906 and the second flow field 908 that face towards the membrane assembly 912. The flow paths, which take the form of serpentine channels 909 in this example, may serve to distribute fluids delivered via the first inlet feed-through passages 905a and second inlet feed-through passages 905b across opposing sides of the membrane assembly 912 as those fluids flow along the flow paths, thereby “wetting” both sides of the membrane assembly 912 (although it will be understood that “wetted,” in this context, refers to whether a surface is in contact with a fluid being flowed, as opposed to actually being in contact with a liquid). Fluid that flows out of the flow paths in the first flow field 906 and the second flow field 908 may respectively flow into first outlet feed-through passages 907a and second outlet feed-through passages 907b.

[0119] Also provided in FIG. 9 are various face seal elements between components on either side of the membrane assembly 912. For example, face-seal element 934a may be locatedDocket No. OPUSP047WObetween the frame 904a and separator plate 901a, face-seal element 934b may be located between frame 904a and MEA support frame 923, face-seal element 934c may be located between frame 904b and separator plate 910b, and face seal element 934d may be located between frame 904b and MEA support frame 925.Rigid Frame Assemblies for MEAs in COXElectrolyzers

[0120] While the above discussion has provided a general overview of various aspects of COXMEA construction and characteristics, the following discussion is intended to address aspects of rigid frame assemblies for MEAs in COXelectrolyzers.

[0121] During manufacturing and assembly of COXelectrolyzers, MEAs can be difficult to handle, position, align, and seal with other elements of the COXelectrolyzer. For example, MEAs used in COXelectrolyzers are made of thin (e.g., about 100 micrometers to about 190 micrometers), non-rigid materials that are difficult to handle because such materials deform easily when handled, such as bending, folding, wrinkling, sagging, or draping, which can quickly and easily lead to unwanted damage to the MEAs when positioning the MEAs in the repeat units, cells, and COXelectrolyzers. These MEAs may be considered flimsy or floppy materials, in some instances. Additionally, these MEAs can be difficult to align and position within the COXelectrolyzers, as well as difficult to test the MEAs and determine whether they have been damaged or sealed improperly during manufacturing. The MEAs are expensive, and it is desirable to reduce damage to, or poor sealing of, the MEAs.

[0122] Provided herein are new and novel assemblies for COXelectrolyzers that have an MEA and two rigid support frames sandwiching and sealing the MEA. The rigid frames are annular structures with central openings that allow fluidic communication to the MEA and thereby allow fluid to reach or flow out of the MEA. At least one of the rigid frames has a recess where an edge region of the MEA is positioned and interposed between the two rigid frames. A seal is also positioned in the recess and in contact with the rigid frame and the MEA to provide a seal to the MEA. In some instances, one or more porous layers may also be positioned adjacent to the MEA and interposed between the two rigid frames. The porous layers may be, in some cases, a gas diffusion layer (GDL) or a porous transport layer (PTL). The porous layers may serve to permit fluids to be transported between the MEA and flow fields, e.g., from the flow fields to the MEA or from the MEA to the flow fields. The fluids transported by the porous layers may, for example, include liquids and / or gases that may be delivered into the electrolyzer or generated within the MEA.

[0123] FIG. 10 depicts an off-angle exploded view of an example assembly for COXelectrolysis. The assembly 1000 has a membrane electrode assembly (“MEA”) 1001, havingDocket No. OPUSP047WOan MEA outer edge 1003 extending around the MEA 1001 and forming an outer boundary of the MEA 1001. The MEA 1001 may be any of the MEAs provided herein above. The assembly 1000 also has a first rigid MEA support frame 1002 with an annular shape that extends around and defines a first opening 1004 that extends through all of the first rigid MEA support frame 1002. The first rigid MEA support frame 1002 (which may be synonymously referred to herein as “first support frame,” “first rigid frame,” or “first frame”) also has a first top surface 1006 with a recess 1008 adjacent to the first opening 1004, and a first bottom surface 1010 opposite the first top surface 1006.

[0124] In some implementations, the annular shape of the first rigid MEA support frame 1002, the shape of the first opening 1004, or both may be rectangular as illustrated. In other implementations, the shape of the first frame 1002, the first opening 1004, or both may differ and may be square, circular, oval, elliptical, triangular, obround, trapezoidal, hexagonal, or the like. In some implementations, the shapes of the first rigid MEA support frame 1002 and the first opening 1004 may match or be the same, such as both being rectangular as shown in FIG.10. In other implementations, the shape of the first rigid MEA support frame 1002 and the shape of the first opening 1004 may differ from each other, such as one being rectangular and the other being elliptical.

[0125] The assembly 1000 also includes a second rigid MEA support frame 1012 with an annular shape that extends around and defines a second opening 1014 that extends through all of the second rigid MEA support frame 1012. The second rigid MEA support frame 1012 (which may be synonymously referred to herein as “second support frame,” “second rigid frame,” or “second frame”) also has a second top surface 1016 and a second bottom surface 1018 opposite the first top surface 1016. Similar to the first rigid frame 1002, in some implementations, the annular shape of the second rigid MEA support frame 1012, the shape of the second opening 1014, or both may be rectangular as illustrated. In other implementations, the shape of the second frame 1012, the second opening 1014, or both may differ and may be square, circular, oval, elliptical, triangular, obround, trapezoidal, hexagonal, or the like. In some implementations, the shapes of the second rigid MEA support frame 1012 and the second opening 1014 may match or be the same, such as both being rectangular as shown in FIG. 10. In other implementations, the shape of the second rigid MEA support frame 1012 and the shape of the second opening 1014 may differ from each other, such as one being rectangular and the other being elliptical.

[0126] The assembly 1000 further includes a first seal 1020 that is in contact with the MEA 1001 and interposed between the first rigid MEA support frame 1002 and the second rigidDocket No. OPUSP047WOMEA support frame 1012. The first seal 1020 also extends around and is radially offset outwards from the first opening 1004 and the second opening 1014. In some instances, the first frame 1002 has a first opening boundary that forms the outer boundary of the first opening 1004, the second frame 1012 has a second opening boundary that forms the outer boundary of the second opening 1014, and the first seal 1020 may have a first seal perimeter that is larger than both the first opening boundary and the second opening boundary.

[0127] Various features of the assembly are further illustrated in FIG. 11 which depicts an exploded cross-sectional side view slice of the assembly of FIG. 10 taken along cross-sectional line A- A in FIG. 10. As can be seen, the first rigid frame 1002 has the first opening 1004 and the recess 1008 adjacent to the first opening 1004. The assembly 1000 has a center axis 1022 that extends through and is perpendicular to a planar surface 1024 of the MEA 1001. As shown in FIG. 11, the recess 1008 is positioned outwards of the outer boundary 1026 of the first opening 1004 in a direction perpendicular to the center axis 1022. In some instances, the outer boundary 1026 is offset from the center axis 1022 by distance DI. Given the shape of the first opening 1004 being rectangular, the distance DI may vary around the center axis 1022.

[0128] The recess 1008 may have a recess inner boundary 1030 and a recess outer boundary 1032 that together form a recess thickness in the direction perpendicular to the center axis 1022. The recess inner boundary 1030 may be positioned at the same distance DI perpendicular to the center axis 1022 and the recess outer boundary 1032 may be positioned at a distance D2, perpendicular to the center axis 1022, greater than distance DI. The outer edge 1003 of the MEA may be positioned at a distance D3 perpendicular to the center axis 1022 that is greater than distance DI and less than distance D2. This sizing is configured to position the MEA 1001 within the recess 1008, including the MEA edge 1003 in the recess 1008 and preventing the MEA edge 1003 from falling through the first or second openings 1004 and 1014. In some implementations, the outer dimensions of MEA 1001 are less than the dimensions of the recess outer boundary 1032 to prevent the MEA 1001 from extending past the recess outer boundary 1032.

[0129] The first seal 1020 is also positioned in the recess 1008, such as at a distance D4 perpendicular to the center axis 1022 that is greater than distance DI and less than distance D2. To provide sealing between the MEA 1001 and one of the rigid frames 1002 or 1012, which in this example is the second frame 1012, the first seal 1020 is also sized and positioned such that the first seal 1020 is closer to the center axis 1022 than the outer edge 1003 of the MEA 1001. In some such instances, the distance D4 is therefore less than distance D3.Docket No. OPUSP047WO

[0130] As also visible in FIG. 11, the first top surface 1006 of the first frame 1002 faces the second bottom surface 1018 of the second frame 1012. In some implementations, when connected together, the first top surface 1006 is in contact with the second bottom surface 1018 like in FIGS. 12 and 13. FIG. 12 depicts the cross-sectional side view slice of the assembly of FIG. 11 and FIG. 13 depicts a magnified view of a portion of the assembly of FIG. 12. The portion of FIG. 12 magnified in FIG. 13 is indicated in FIG. 12 with Circle B having a dashdot-dot boundary line. As shown in FIG. 12, the first seal 1020 is positioned in the recess 1008 and is in contact with the surface 1024 of the MEA 1001. The outer edge 1003 is also positioned in the recess 1008. In some instances, like in FIGS. 11 and 12, the first seal 1020 may be interposed between the MEA 1001 and the second rigid frame 1012. This may include the first seal 1020 being in contact with the second bottom surface 1018 of the second rigid frame 1012.

[0131] As provided herein, the first frame 1002 and second frame 1012 are connected together. For example, in FIG. 13, the first frame 1002 and second frame 1012 are in contact with each other and they may be connected, or coupled, to each other in various manners. This may include fasteners like strews, bolts, clips, clamps, and the like. These fasteners may also provide a detachable connection configured to allow the two frames to be coupled and uncoupled from each other without damaging the frames. In some implementations, the first frame 1002 and second frame 1012 may be connected to each other using an adhesive, glue, tape, welding, ultrasonic welding, stakes, and the like.

[0132] Further illustrated in FIG. 13 are the distances of various features. For example, the outer boundary 1026 at distance DI, the recess inner boundary 1030 at distance DI, and the recess outer boundary 1032 at distance D2 perpendicular to the center axis 1022 are depicted. The outer edge 1003 of the MEA 1001 is also positioned in the recess 1008 at the distance D3 perpendicular to the center axis 1022 while the first seal 1020 is also positioned in the recess 1008 and at the distance D4 that is greater than distance DI and less than distance D3.

[0133] FIG. 14 depicts a top view of the assembly of FIG. 10. Here, the assembly 1000 is transparent so that some internal features are visible. The center axis 1022 of the MEA 1001 is marked with an X and is perpendicular to the page of the Figure. Here, the MEA 1001 is visible through the first opening 1004, and the outer boundary 1026 of the first opening 1004 is also identified. The recess 1008 is indicated with shading, its recess inner boundary 1030 overlaps with the outer boundary 1026, and its recess outer boundary 1032 is identified with dashed lines. The outer edge 1003 of the MEA 1001 and the first seal 1020 are positioned in the recess 1008. As seen in FIG. 14, when viewed perpendicular to the center axis 1022, the first seal 1020 extends around, or encircles, and is offset outwards of the center axis 1022 with respectDocket No. OPUSP047WOto the first opening 1004. Similarly, the outer edge 1003 of the MEA 1001 extends around, or encircles, and is offset outwards of the center axis 1022 with respect to the first seal 1020. The recess outer boundary 1032 also extends around, or encircles, and is offset outwards of the center axis 1022 with respect to the first seal 1020 and the MEA outer edge 1003.

[0134] FIG. 14 also shows the distances of various features provided above. For example, the recess inner boundary 1030 at distance DI, the recess outer boundary 1032 at distance D2, the outer edge 1003 positioned at the distance D3 perpendicular to the center axis 1022, and first seal 1020 positioned at distance D4 are all shown here. Each of these distances may vary around the center axis 1022, but their relationships with respect to each other remain the same. For instance, at any point around the center axis 1022, distance D2 is greater than distances DI, D3, and D4, while distance D3 is greater than distances DI and D4.

[0135] The first seal may be positioned in various locations within the recess. For example, in FIGS. 11-13, the first seal 1020 is interposed between the MEA 1001 and the second rigid frame 1012. Further, the first seal 1020 is in contact with the second bottom surface 1018 and the MEA 1001 is in contact with a surface 1034 of the recess 1008. In some other implementations, the first seal may be positioned differently than in FIGS. 11-13, such as flipped. FIG. 15 depicts a magnified cross-sectional side view slice of a portion of another assembly. The magnified portion in FIG. 15 may be considered the same detailed area of a cross-sectioned assembly like Circle B in FIG. 12 and shown in FIG. 13, although the assembly in FIG. 15 is similar to, but different than, the assembly of FIGS. 12 and 13. In the assembly 1500 here, the first seal 1020 is interposed between the MEA 1001 and the first frame 1002, and in contact with both the MEA 1001 and the surface 1034 of the first rigid frame 1002. The MEA 1001 is in contact with the second bottom surface 1018 of the second rigid frame 1012 in this example.

[0136] In some other implementations, the first seal may be positioned in a groove of one of the rigid frames. FIG. 16 depicts a cross-sectional side view slice of a portion of yet another assembly. The magnified portion in FIG. 16 may be considered the same detailed area of a cross-sectioned assembly like Circle B in FIG. 12 and shown in FIG. 13, although the assembly in FIG. 16 is similar to, but different than, the assembly of FIGS. 12 and 13. In this example, assembly 1600 has the second rigid frame 1012 with a groove 1036 that extends through the second bottom surface 1018 and extends around the center axis 1022. The first seal 1020 is positioned in the groove 1036 which may provide for additional sealing benefits, in some instances. For example, the assembly 1000 may be able to experience high pressures and utilize different seal materials when a groove is utilized.Docket No. OPUSP047WO

[0137] In some implementations, the assembly may have two seals, one on each side of the MEA 1001. FIG. 17 depicts a cross-sectional side view slice of a portion of another assembly. The magnified portion in FIG. 17 may be considered the same detailed area of a cross-sectioned assembly like Circle B in FIG. 12 and shown in FIG. 13, although the assembly in FIG. 17 is similar to, but different than, the assembly of FIGS. 12 and 13. In this example, the assembly 1700 has a first seal 1020 like in FIGS. 10-13 and a second seal 1738. The first seal 1020 is again interposed between the MEA 1001 and the second rigid frame 1012, and in contact with both the MEA 1001 and the second bottom surface 1018 of the second rigid frame 1012. The second seal 1738 is positioned in the recess 1008 and interposed between the MEA 1001 and the first rigid frame 1012. The second seal is also in contact with both the MEA 1001 and the surface 1034 of the first rigid frame 1002. The MEA 1001 is interposed between the first seal 1020 and the second seal 1738. In some implementations, the second seal 1738 extends around the center axis 1022 and is positioned at the fourth distance D4 with respect to the center axis 1022. For example, the second seal 1738 is positioned closer to the center axis than the edge 1003 of the MEA 1001 and farther from the center axis 1022 than the boundaries 1030 and 1026. Although not depicted here, in some implementations with two seals, one or both seals may be positioned in a groove of a respective rigid frame, similar to that of groove 1036 in FIG. 16.

[0138] In some implementations, the assembly may only have the first seal and the MEA that are interposed between the first and second rigid frames 1002 and 1012. In some implementations with two seals, the assembly may only have the first seal, the second seal, and the MEA, that are interposed between the first and second rigid frames 1002 and 1012. In other words, there may be no other structures or features positioned within the assembly, and the assembly may be without any other structures or features positioned within the assembly or between the rigid frames. For example, referring to FIG. 13, the assembly 1000 does not have any other structure positioned in between the first rigid frame 1002 and the second rigid frame 1012, or positioned inside the recess 1008.

[0139] In other implementations, the assembly may have one or more porous layers positioned between the first and second rigid frames. As noted above, these porous layers may be a GDE, PTE, or both, in some cases. FIG. 18 depicts an exploded cross-sectional side view slice of a portion of yet another assembly. This Figure is similar to that of FIG. 11, with noted differences. The cross-section of FIG. 18 may be considered taken along the same cross-sectional line A-A of FIG. 11. In this example, the assembly 1800 has a first porous layer 1840 which may be a GDE, PTE, or other permeable layer of material. The first porous layer 1840Docket No. OPUSP047WOis positioned adjacent to the MEA 1001 and may be in direct contact with the MEA 1001. To accommodate the first porous layer 1840, the assembly 1800 has a second recess 1842 which in this example is in the second rigid frame 1812 and outlined with a dashed rectangle. Similar to the recess 1008, the second recess 1842 extends around the center axis 1022 and is adjacent to the second opening 1814 of the second rigid frame 1812. As can be seen, the first porous layer 1840 is interposed between the second rigid frame 1812 and the MEA 1001. The first porous layer 1840 may have a first layer outer edge 1844 that extends around the center axis 1022 and is closer to the center axis 1022 than the first seal 1020 and the MEA outer edge 1003.

[0140] Additional features of assembly 1800 are illustrated in FIG. 19 which depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 18. The portion of FIG. 18 magnified in FIG. 19 is indicated in FIG. 18 with Rectangle C having a dash-dot-dot boundary line. This Figure is similar to that of FIG. 13, with noted differences. Here, the second recess 1842 may have a second recess outer boundary 1846 that is closer to the center axis 1022 than the first seal 1020. The first layer outer edge 1844 is positioned at a distance D5 perpendicular to the center axis 1022 and the second recess outer boundary 1846 is positioned at distance D6 perpendicular to the center axis 1022. Distance D5 is less than distance D6, and distances D5 and D6 are less than distances D4, D3, and D2. Including the first porous layer 1840 in the assembly 1800 may have numerous advantages, such as reducing structures and process steps needed to retain or position the porous layer during assembly, providing easier alignment between the MEA and the first porous layer, and sealing the peripheral edge of the first porous layer 1840 such that fluids (e.g., liquids and / or gasses) introduced to the assembly 1800 are prevented from flowing around the peripheral edge of the first porous layer 1840, which would cause such fluids to avoid fulfilling their roles in the desired reaction(s) of the electrochemical cell.

[0141] In some implementations, the assembly may have the first porous layer positioned in a second recess of the first rigid frame. FIG. 20 depicts an exploded cross-sectional side view slice of a portion of another assembly. This Figure is similar to that of FIGS. 11 and 18, with noted differences. The cross-section of FIG. 20 may be considered taken along the same cross-sectional line A- A of FIG. 11. In this example, the assembly 2000 has a first porous layer 2040 which may be a GDE, PTE, or other permeable layer of material. The first porous layer 2040 is positioned adjacent to the MEA 1001 and may be in direct contact with the MEA 1001. To accommodate the first porous layer 2040, the assembly 2000 has a second recess 1842 which in this example is in the first rigid frame 2002 and outlined with a dashed rectangle. The secondDocket No. OPUSP047WOrecess 2042 is adjacent to the recess 2008 and the first opening 2004, and similar to the recess 2008, the second recess 2042 extends around the center axis 1022. The first porous layer 2040 is interposed between the first rigid frame 2002 and the MEA 1001. The first porous layer 2040 may have a first layer outer edge 2044 that extends around the center axis 2022 and is closer to the center axis 1022 than the first seal 1020 and the MEA outer edge 1003. Regardless of the particular arrangement of the assemblies discussed herein for securing the MEA and / or the first porous layer, the interface between the rigid frames and the MEA or the first porous layer are designed to secure the materials positioned between the rigid frames without damaging such materials.

[0142] Additional features of assembly 2000 are illustrated in FIG. 21 which depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 20. This Figure is similar to that of FIGS. 13 and 19, with noted differences. The portion of FIG. 20 magnified in FIG. 21 is indicated in FIG. 20 with Rectangle D having a dash-dot-dot boundary line. Here, the second recess 2042 may have a second recess outer boundary 2046 that is closer to the center axis 1022 than the first seal 1020. As seen here, the first layer outer edge 2044 is positioned at a distance D5 perpendicular to the center axis 1022 and the second recess outer boundary 2046 is positioned at distance D6 perpendicular to the center axis 1022. Distance D5 is less than distance D6, and distances D5 and D6 are less than distances D4, D3, and D2. Including the first porous layer 2040 in the assembly 1800 may have numerous advantages, like those provided above with respect to FIGS. 18 and 19. It will be understood that the advantages discussed above with respect to FIGS. 18 and 19 may apply, in whole or in part, to assemblies that only incorporate the MEA between the rigid frames.

[0143] In some implementations, the assembly may have the first porous layer positioned in a second recess of the first rigid frame and a second porous layer in a recess of the second rigid frame. This assembly may be a combination of features from assemblies 1800 and 2000, such as the second rigid frame 1812 of assembly 1800 and the first rigid frame 2002 of assembly 2000.

[0144] FIG. 22 depicts an exploded cross-sectional side view slice of a portion of yet another assembly. This Figure is similar to that of FIGS. 11, 18, and 20 with noted differences. The cross-section of FIG. 22 may be considered taken along the same cross-sectional line A-A of FIG. 11. In this example, the assembly 2200 has a first porous layer 2240 and a second porous layer 2241, which may be a GDE, PTE, or other permeable layer of material. For example, the first porous layer 2240 may be a GDE and the second porous layer 2241 may be a PTE, or vice versa. The first rigid frame 2002 in assembly 2200 may be configured the same as the first rigidDocket No. OPUSP047WOframe 2002 in assembly 2000 described herein as indicated by the same reference numerals. Similarly, the first porous layer 2240 may be positioned like the first porous layer 2040 described herein. The second rigid frame 1812 in assembly 2200 may be configured the same as the second rigid frame 1812 in assembly 1800 described herein as indicated by the same reference numerals. Similarly, the second porous layer 2241 may be positioned like the first porous layer 1840 described herein.

[0145] For example, as can be seen in FIG. 22, the first porous layer 2240 is positioned adjacent to the MEA 1001 and may be in direct contact with the MEA 1001. To accommodate the first porous layer 2240, the assembly 2200 has the second recess 2042 in the first rigid frame 2002 like described herein with respect to FIGS. 20 and 21. The second recess 2042 is adjacent to the recess 2008 and the first opening 2004, and similar to the recess 2008, the second recess 2042 extends around the center axis 1022. As can be seen, the first porous layer 2240 is interposed between the first rigid frame 2002 and the MEA 1001. The first porous layer 2240 may have a first layer outer edge 2244 that extends around the center axis 2022 and is closer to the center axis 1022 than the first seal 1020 and the MEA outer edge 1003.

[0146] The second porous layer 2241 is positioned like that of first porous layer 1840 in FIGS.18 and 19. It is positioned adjacent to the MEA 1001 and may be in direct contact with the MEA 1001. To accommodate the second porous layer 2241, the assembly 2200 has a third recess 1842 which may be the same as the second recess 1842 provided herein. Similar to the recess 1008, the third recess 1842 extends around the center axis 1022 and is adjacent to the second opening 1814 of the second rigid frame 1812. The second porous layer 2241 is interposed between the second rigid frame 1812 and the MEA 1001. The second porous layer 2241 may have a second layer outer edge 1844 that extends around the center axis 1022 and is closer to the center axis 1022 than the first seal 1020 and the MEA outer edge 1003.

[0147] Additional features of assembly 2200 are illustrated in FIG. 23 which depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 22. This Figure is similar to that of FIGS. 13, 19, and 21, with noted differences. The portion of FIG. 23 magnified in FIG. 22 is indicated in FIG. 22 with Rectangle E having a dash-dot-dot boundary line. Here, the second recess 2042 may have a second recess outer boundary 2046 that is closer to the center axis 1022 than the first seal 1020. The first layer outer edge 2044 is positioned at a distance D5 perpendicular to the center axis 1022 and the second recess outer boundary 2046 is positioned at distance D6 perpendicular to the center axis 1022. Distance D5 is less than distance D6, and distances D5 and D6 are less than distances D4, D3, and D2.Docket No. OPUSP047WO

[0148] Further in FIG. 23, the third recess 1842 may have a third recess outer boundary 1846 that is closer to the center axis 1022 than the first seal 1020. As seen here, the second layer outer edge 1844 is positioned at a distance D7 perpendicular to the center axis 1022 and the second recess outer boundary 1846 is positioned at distance D8 perpendicular to the center axis 1022. Distance D7 is less than distance D8, and distances D7 and D8 are less than distances D4, D3, and D2.

[0149] In some implementations, it may be advantageous to have one or more seals between the rigid frames in order to provide a seal with other components in the COXelectrolyzer stack. These additional seals may be radially outside the recesses and outer edge of the MEA. FIG.24 depicts an exploded cross-sectional side view slice of a portion of another assembly. The cross-section of FIG. 24 may be considered taken along the same cross-sectional line A-A of FIG. 11. This assembly 2400 is illustrated the same as assembly 1000 with noted differences. Here, assembly 2400 has another seal, such as a third seal 2448 positioned in between the first rigid frame 1002 and the second rigid frame 1012, and in contact with both the first top surface 1006 of the first rigid frame 1002 and the second bottom surface 1018 of the second rigid frame 1012. The third seal 2448 is also positioned farther from the center axis 1022 than the recess 1008, the first seal 1020, and the outer edge 1003 of the MEA 1001. In this example, the third seal 2448 is positioned at distance D5 from the center axis in a direction perpendicular to the center axis 1022 which is greater than distances DI to D4. This third seal 2448 may prevent liquids and gases from manifolds or other elements outside the assembly 1000, such as outside the frames 1002 and 1012, from entering the assembly 1000 and contacting the MEA 1001.

[0150] Additional features of assembly 2400 are illustrated in FIG. 25 which depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 24. This FIG. 25 may be the same as FIG. 13, with noted differences. The portion of FIG. 24 magnified in FIG.25 is indicated in FIG. 24 with Rectangle F having a dash-dot-dot boundary line. Here, the third seal 2448 is shown, and it is interposed between the first rigid frame 1002 and the second rigid frame 1012. Although not depicted, it shall be understood that that the first rigid frame 1002, the second rigid frame 1012, or both may have a groove to accommodate and receive the third seal 2448. The third seal 2448 may be provided in any of the other assemblies provided herein, such as assemblies 1500, 1700, 1800, 2000, and 2200.

[0151] In some implementations, the assembly may further include an anode frame and a cathode frame that are connected to the first and second rigid MEA support frames. Additional aspects of these anode and cathode frames are provided farther above. FIG. 26 depicts an exploded off-angle view of another assembly having an anode frame and a cathode frame.Docket No. OPUSP047WOAssembly 2600 has a first rigid MEA support frame 2602 which may have some of the same features provided above with respect to any of the other first rigid fames, such as rigid frames 1002 and 1802. In this example, the first rigid frame 2602 has an annular shape that extends around and defines a first opening 2604 that extends through all of the first rigid MEA support frame 2602. The first rigid frame 2602 also has a first top surface 2606 with a recess 2608 adjacent to the first opening 2604, and a first bottom surface (not visible here) opposite the first top surface 2606.

[0152] Assembly 2600 has a second rigid MEA support frame 2612 which may have some of the same features provided above with respect to any of the other second rigid fames, such as rigid frames 1012, 1812, and 2012. In this example, the second rigid frame 2612 has an annular shape that extends around and defines a second opening 2614 that extends through all of the second rigid frame 2612. The second rigid frame 2612 also has a second top surface 2616 and a second bottom surface 2618 opposite the first top surface 2616. The assembly 2600 further has an MEA 2601 with an outer edge 2603, and the first seal 2620, as provided herein and similar to that of assembly 1000.

[0153] Also included in assembly 2600 is a cathode frame 2631 and an anode frame 2615. Although not depicted here for illustration purposes, the assembly 2600 also includes cathode and anode flow fields as described herein. The cathode frame 2631 may have an annular body in various shapes, which in this example is rectangular, and the annular body defines a third opening 2650 that extends through the cathode frame 2631. The second rigid frame 2612 and the cathode frame 2631 are configured to be connected to each other and in some instances, provide a seal interface between the two frames. The anode frame 2615 may also have an annular body in various shapes, which in this example is rectangular, and the annular body defines a fourth opening 2652 that extends through the anode frame 2615. The first rigid frame 2602 and the anode frame 2615 are also configured to be connected to each other and in some instances, provide a seal interface between the two frames.

[0154] As can be seen here, the second rigid frame 2612 has a second flange 2654 that extends around all of the frame 2612 and is configured to interface with the cathode frame 2631. In some instances, like in FIG. 26, the assembly 2600 includes a third seal 2656 that is interposed between the second flange 2654 and the cathode frame 2631 to provide a seal between the second rigid frame 2612 and the cathode frame 2631. Similarly, the first rigid frame 2602 may have a first flange 2658 that extends around all of the frame 2602 and is configured to interface with the anode frame 2615. In some instances, like in FIG. 26, the assembly 2600 includes a fourth seal 2660 that is interposed between the first flange 2658 and the anode frame 2615 toDocket No. OPUSP047WOprovide a seal between the first rigid frame 2602 and the anode frame 2615. These third and fourth seals may advantageously prevent liquid and / or gas from traveling between these elements which may adversely affect the processes occurring in and between the elements, such as the cathode frame, cathode flow field, MEA, anode flow field, and anode frame.

[0155] FIG. 27 depicts an exploded cross-sectional side view slice of the assembly of FIG. 26 taken along cross-sectional line G-G in FIG. 26. Here, the MEA 2601, first seal 2620, first rigid frame 2602, and second rigid frame 2612 are shown. The first rigid frame 2602 has the recess 2608 configured to receive the outer region of the MEA 2601 including the edge 2603, and the first seal 2620, like described above. As mentioned, the first rigid frame 2602 and second rigid frame 2612 may be configured like any of the other first and second rigid frames provided herein, such as those illustrated in FIGS. 10 to 23.

[0156] In FIG. 27, the first rigid frame 2602 has the first flange 2658 that is radially outwards of the rest of the annular body of the frame 2602. The third seal 2656 is interposed between the first rigid frame 2602 and the anode frame 2615, such as between the first flange 2658 and the anode frame 2615. In some cases, like here, the anode frame 2615 may also include an anode frame recess 2662 opposite the first flange 2658 and adjacent to the fourth opening 2652. The anode frame recess 2662 is configured to receive and engage with the first flange 2658 and thereby sandwich the fourth seal 2660 therebetween.

[0157] As further illustrated in FIG. 27, the second rigid frame 2612 has the second flange 2654 that is radially outwards of the rest of the annular body of the frame 2612. The fourth seal 2660 is interposed between the second rigid frame 2612 and the cathode frame 2631, such as between the second flange 2654 and the cathode frame 2631. In some cases, like here, the cathode frame 2631 may also include a cathode frame recess 2664 opposite the second flange 2654 and adjacent to the third opening 2650. The cathode frame recess 2664 is configured to receive and engage with the second flange 2654 and thereby sandwich the third seal 2656 therebetween.

[0158] In some implementations, the assembly 2600 has an anode flow field 2611 and a cathode flow field 2627. The anode flow field 2611 may be adjacent to the fourth opening 2652 and interposed between or adjacent to the anode frame 2615 and the first rigid frame 2602. Similarly, the cathode flow field 2627 may be adjacent to the third opening 2650 and interposed between or adjacent to the cathode frame 2631 and the second rigid frame 2612. As can be seen here, the cathode flow field 2627 is at least partially disposed in the third opening 2650 of the cathode frame and the anode flow field 2611 is at least partially disposed in the fourth 2652 of the anode frame 2615. Further, the MEA 2601, the first rigid MEA support frame 2602,Docket No. OPUSP047WOand the second MEA support frame 2612 are interposed between the cathode frame 2631 and the anode frame 2615. In some instances, the MEA may have a cathodic part 2624, an anodic part 2666, and a separator (not illustrated) between the cathodic part 2624 and the anodic part 2666. The cathode frame 2631 is adjacent to the cathodic part 2624, the anode frame 2615 is adjacent to the anodic part 2666. The cathode frame 2631 and the anode frame 2615 may be coupled to each other with a plurality of fasteners, not illustrated here.

[0159] FIG, 28 depicts a magnified cross-sectional slice of a portion of the assembly of FIG.27. The portion of FIG. 27 magnified in FIG. 28 is indicated in FIG. 27 with Rectangle H having a dash-dot-dot boundary line. For clarity, the flow fields have been omitted and the cross-hatching has been removed. In this Figure, some of the various features of the assembly 2600 are further illustrated. For example, the fourth seal 2660 is interposed between the first flange 2658 and the anode frame 2615. The anode frame recess 2662 is engaged with the first flange 2658 such that the first flange 2658 is in the anode frame recess 2662 and the fourth seal 2660 is sandwiched between the first flange 2658 and the anode frame 2615. Similarly, the third seal 2656 is interposed between the second flange 2654 and the cathode frame 2631. The cathode frame recess 2664 is engaged with the second flange 2654 such that the second flange 2654 is in the cathode frame recess 2664 and the third seal 2656 is sandwiched between the second flange 2654 and the cathode frame 2631. In this illustration, the anode and cathode frames may be positioned radially outwards of the recess 2608 and of aspects of the first rigid frame 2602 and the second rigid frame 2612.

[0160] In some implementations, the anode frame and cathode frame may be combined into a single anode-cathode frame, and this single anode-cathode frame, may be positioned on either side of the assemblies provided herein, such as assemblies 1000, 1500, 1600, 1700, 1800, 2000, 2200, and 2400. For example, the single anode-cathode frame may be positioned adjacent to frame 1012 of assembly 1000. The other frame 1002 may be connected to a separator plate, or other plate like a bipolar layer or plate. Together, these components may provide for another unitized assembly or repeat unit that may be connected together with other such assemblies or units. In some implementations, the assembly 1000 maybe positioned within the single anodecathode frame similar to that illustrated between frames 2612 and 2631, or between frames 2602 and frame 2615. For example, this positioning may include frame 2631 having the frame recess 2662 and the frame 2612 having the second flange 2654 positioned in the frame recess 2662, as well as the seal 2656.

[0161] In some such implementations, the single anode-cathode frame may have a cathode flow field and an anode flow field. The single anode-cathode frame may also have an opening,Docket No. OPUSP047WOlike opening 2650 provided above, and both the cathode and anode flow fields may be positioned in the opening 2650. As provided herein, the MEA may have an anodic part, a cathodic part, and a separator between these two parts. In some instances, the single anodecathode frame is positioned adjacent to, or in contact with, the first or second frames 1002 and 1012 such that the anode flow field of the single anode-cathode frame is adjacent to the anodic part of the MEA. Similarly, in some other instances, the single anode-cathode frame is positioned adjacent to, or in contact with, the first or second frames 1002 and 1012 such that the cathode flow field of the single anode-cathode frame is adjacent to the cathodic part of the MEA.

[0162] The first seal provided herein may be various types of seals. In some implementations, the seal may be an O-ring, like those depicted in FIGS. 10-16. The first seal may alternatively, or additionally, be an adhesive tape, screen-printed, a dispensed seal, a sprayed seal, or a molded seal. As illustrated in FIG. 16, the first seal may be positioned within a groove of one of the rigid frames or positioned on a planar surface of the rigid frame, like in FIG. 13. The cross-sectional areas of the first seal may also differ. For example, the first seal may have a cross-section that is circular, sawtooth, rectangular, obround, elliptical, trapezoidal, triangular, one or more semicircular portions, or a combination thereof.

[0163] FIGS. 29A-29D depict magnified cross-sectional side view slices of portions of MEA assemblies with various seals. FIG. 29A depicts a magnified cross-sectional side view slice of a portion of the assembly of FIG. 10. The portion of FIG. 10 magnified in FIG. 29A is indicated in FIG. 10 with Rectangle I having a dash-dot-dot boundary line. Here in FIG. 29A, the first seal 2920A has a circular cross-sectional area and is in direct contact with the MEA 1001 and the second bottom surface 1018 of the second rigid frame 1012. FIG. 29B depicts a magnified cross-sectional side view slice of a portion of another assembly. The magnified portion in FIG.29B may be considered the same detailed area of a cross-sectioned assembly like Rectangle I in FIG. 13 and shown in FIG. 29A, although the assembly in FIG. 29B is similar to, but different than, the assembly of FIGS. 12, 13, 29A. In FIG. 29B, the first seal 2920B has a rectangular cross-sectional area and is in direct contact with the MEA 1001 and the second bottom surface 1018 of the second rigid frame 1012.

[0164] FIG. 29C depicts a magnified cross-sectional side view slice of a portion of another assembly. The magnified portion in FIG. 29C may be considered the same detailed area of a cross-sectioned assembly like Rectangle I in FIG. 13 and shown in FIG. 29A, although the assembly in FIG. 29C is similar to, but different than, the assembly of FIGS. 12, 13, 29A. In FIG. 29C, the first seal 2920C has a cross-sectional area with two semicircular portions and isDocket No. OPUSP047WOin direct contact with the MEA 1001 and the second bottom surface 1018 of the second rigid frame 1012. In some instances, the first seal 2920C may have more than two semicircular portions. FIG. 29D depicts a magnified cross-sectional side view slice of a portion of another assembly. The magnified portion in FIG. 29D may be considered the same detailed area of a cross-sectioned assembly like Rectangle I in FIG. 13 and shown in FIG. 29A, although the assembly in FIG. 29D is similar to, but different than, the assembly of FIGS. 12, 13, 29A. In FIG. 29D, the first seal 2920D has a sawtooth cross-sectional area with two triangular portions and is in direct contact with the MEA 1001 and the second bottom surface 1018 of the second rigid frame 1012. In some instances, the first seal 2920D may have a single triangle portion or more than more than two triangular portions.

[0165] Any seal discussed herein may be configured as illustrated in FIGS. 29A-29D and described herein. Further, any seal may also be positioned in a groove, as illustrated in FIG.16. For assemblies with more than one seal, such seals may be the same as each other or may be different. These seals may have cross-sectional areas or shapes like those shown in FIGS.29A-29D. For example, one seal may have a circular cross-sectional area like seal 2920A and another one of the seals may have a rectangular cross-sectional area like seal 2920B. Additionally, one of the seals may be positioned in direct contact with either the second bottom surface of the second rigid frame or the recess (e.g., like surface 1034) while the second seal may be positioned in a groove.

[0166] In some implementations, the first seal may be positioned within the recess and may not be in direct contact with the MEA. Various features of the first seal may be the same as provided above, except for noted differences. FIG. 30 depicts a magnified cross-sectional side view slice of a portion of another assembly similar to that of FIG. 24. This FIG. 30 may have some of the same features as FIG. 13, with noted differences. The magnified portion in FIG.30 may be the same area indicated in FIG. 24 with Rectangle F having a dash-dot-dot boundary line. Here in FIG. 30, the first seal 3020 of the assembly 3000 is positioned in the recess 3008 and positioned radially outward of the outer edge 1003 of the MEA 1001 by a distance D9 from the center axis 1022. This distance D9 is greater than the distance D3 which represents the distance of the outer edge 1003 of the MEA 1001. In other words, the first seal 3020 has a larger perimeter than the MEA 1001 and the first seal 3020 extends around, or encircles, the MEA 1001. As can be seen further, the first seal 3020 is not in contact with the MEA 1001.

[0167] In this example, the recess 3008 is sized smaller than some other implementations herein. The first seal 3020 is in direct contact with both the second bottom surface 1018 of the second rigid frame 1012, and the surface 3034 of the recess 3008 of the first rigid frame 3002.Docket No. OPUSP047WOSimilarly, the first seal 3020 is in direct contact with both the second bottom surface 1018 of the second rigid frame 1012, and the surface 3034 of the recess 3008 of the first rigid from 3002. This configuration of the first seal 3008 and assembly 3000 may provide a seal for the MEA 1001 that prevents liquid, gas, or both from traveling through the recess 3008 and around the outer edge 1003 of the MEA 1001, in some implementations. In various implementations, a connection or coupling between the first rigid frame 3002 and the second rigid frame 1012 may provide a sufficient amount of compressive force to an edge region or perimeter of the MEA 1001 to at least partially seal the MEA 1001 to prevent liquid, gas, or both from traveling through the recess 3008.

[0168] Also shown in FIG. 30 is the third seal 2448 which is interposed between the first rigid frame 3002 and the second rigid frame 1012. Although not depicted, it shall be understood that that the first rigid frame 3002, the second rigid frame 1012, or both may have a groove to accommodate and receive the third seal 2448. The third seal 2448 may also be configured to connect, or couple, the first rigid frame 3002 and the second rigid frame 1012 to each other. In some instances, the third seal 2448 may be an adhesive, tape, glue, or other fastener feature.

[0169] While discussion has been provided relating to positioning the MEA between the first rigid frame and the second rigid frame, alternative arrangements are contemplated within the scope of the concepts discussed herein. For example, the present disclosure provides solutions relevant to securing permeable and / or flexible components between rigid frames in an effort to seal such components and / or improve the handleability of such components. Accordingly, it is contemplated that a greater number of components, or a fewer number of components, than those expressly discussed above may be positioned between the first rigid frame and the second rigid frame without departing from the concepts discussed herein. For example, the components positioned between the first rigid frame and the second rigid frame can include, but are not limited to, an anion exchange membrane, a proton exchange membrane, a bipolar membrane, a cathode, and / or an anode.Additional and / or Alternative Embodiments

[0170] Unless otherwise specified, the illustrated embodiments are to be understood as providing example features of varying detail of some embodiments. Thus, unless otherwise specified, the features, components, regions, aspects, structures, etc. (hereinafter individually or collectively referred to as an “element” or “elements”), of the various illustrations may be otherwise combined, separated, interchanged, and / or rearranged without departing from the teachings of the disclosure.Docket No. OPUSP047WO

[0171] The terminology used herein is for the purpose of describing some embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is to be understood that the phrases “for each <item> of the one or more <items>,” “each <item> of the one or more <items>,” and / or the like, if used herein, are inclusive of both a single-item group and multiple-item groups, i.e., the phrase “for . . . each” is used in the sense that it is used in programming languages to refer to each item of whatever population of items is referenced. For example, if the population of items referenced is a single item, then “each” would refer to only that single item (despite dictionary definitions of “each” frequently defining the term to refer to “every one of two or more things”) and would not imply that there must be at least two of those items. Similarly, the term “set” or “subset” should not be viewed, in itself, as necessarily encompassing a plurality of items — it is to be understood that a set or a subset can encompass only one member or multiple members (unless the context indicates otherwise). The terms “comprises,” “comprising,” “includes,” and / or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and / or provided values that would be recognized by one of ordinary skill in the art. Accordingly, the term “substantially” as used herein, unless otherwise specified, means within 5% of a referenced value. For example, substantially perpendicular means within ±5% of parallel.

[0172] It is also to be understood that the various dimensional parameter ranges provided herein may be combined with any other dimensional parameter ranges provided herein. For example, if a channel is described as potentially having a length in ranges A, B, or C, a width in ranges D, E, or F, and a depth in ranges G, H, or I, this is to be understood to explicitly contemplate channels having a length, width, and depth representing any combination of such ranges. For example, in the above scenario, such a channel may have a length, width, and height of AEI, AEJ, AEK, AEL, AFI, AFJ, AFK, AFL, AGI, AGJ, AGK, AGL, AHI, AHJ, AHK, AHL, BEI, BEJ, BEK, BEL, BFI, BFJ, BFK, BFL, BGI, BGJ, BGK, BGL, BHI, BHJ, BHK, BHL, CEI, CEJ, CEK, CEL, CFI, CFJ, CFK, CFL, CGI, CGJ, CGK, CGL, CHI, CHJ, CHK, CHL, DEI, DEJ, DEK, DEL, DFI, DFJ, DFK, DFL, DGI, DGJ, DGK, DGL, DHI, DHJ, DHK, or DHL, with the first letter of each letter triplet representing the length range of theDocket No. OPUSP047WOchannel, the second letter of each letter triplet representing the width range of the channel, and the third letter of each letter triplet representing the depth range of the channel.

[0173] The use of cross-hatching and / or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and / or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and / or descriptive purposes. As such, the sizes and relative sizes of the respective elements are not necessarily limited to the sizes and relative sizes shown in the drawings. When an embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order.

[0174] When an element, such as a frame, is referred to as being “on,” “connected to,” or “coupled to” another element, it may be directly on, directly connected to, or directly coupled to the other element or at least one intervening element may be present. When, however, an element is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element, there are no intervening elements present. Other terms and / or phrases if used herein to describe a relationship between elements should be interpreted in a like fashion, such as “between” versus “directly between,” “adjacent” versus “directly adjacent,” “on” versus “directly on,” etc. Further, the term “connected” may refer to physical, electrical, and / or fluid connection. To this end, for the purposes of this disclosure, the phrase “fluidically connected” is used with respect to volumes, plenums, holes, orifices, etc., that may be connected to one another, either directly or via one or more intervening components or volumes, to form a fluidic connection, similar to how the phrase “electrically connected” is used with respect to components that are connected to form an electric connection.

[0175] For the purposes of this disclosure, “at least one of X, Y, . . ., and Z” and “at least one selected from the group consisting of X, Y, . . ., and Z” may be construed as X only, Y only, . . ., Z only, or any combination of two or more of X, Y, . . ., and Z, such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0176] Although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are usedDocket No. OPUSP047WOto distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure. To this end, use of such identifiers, e.g., “a first element,” should not be read as suggesting, implicitly or inherently, that there is necessarily another instance, e.g., “a second element.” Further, the use, if any, of ordinal indicators, such as (a), (b), (c), . . ., or (1), (2), (3), . . ., or the like, in this disclosure and accompanying claims, is to be understood as not conveying any particular order or sequence, except to the extent that such an order or sequence is explicitly indicated. For example, if there are three steps labeled (i), (ii), and (iii), it is to be understood that these steps may be performed in any order (or even concurrently, if not otherwise contraindicated), unless indicated otherwise. For example, if step (ii) involves the handling of an element that is created in step (i), then step (ii) may be viewed as happening at some point after step (i). In a similar manner, if step (i) involves the handling of an element that is created in step (ii), the reverse is to be understood.

[0177] Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one element’s spatial relationship to at least one other element as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and / or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” or “over” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly.

[0178] The term “between,” as used herein and when used with a range of values, is to be understood, unless otherwise indicated, as being inclusive of the start and end values of that range. For example, between 1 and 5 is to be understood as inclusive of the numbers 1, 2, 3, 4, and 5, not just the numbers 2, 3, and 4.

[0179] As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the phrases “for each <item> of the one or more <items>,” “each <item> of the one or more <items>,” and / or the like, if used herein, are inclusive of both a single-item group and multiple-item groups, i.e., the phrase “for . . . each” is used in the sense that it is used in programming languages to refer to each item of whatever population of items is referenced.Docket No. OPUSP047WOFor example, if the population of items referenced is a single item, then “each” would refer to only that single item (despite dictionary definitions of “each” frequently defining the term to refer to “every one of two or more things”) and would not imply that there must be at least two of those items. Similarly, the term “set” or “subset” should not be viewed, in itself, as necessarily encompassing a plurality of items — it is to be understood that a set or a subset can encompass only one member or multiple members (unless the context indicates otherwise). In addition, the terms “comprises,” “comprising,” “includes,” and / or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0180] Various embodiments are described herein with reference to sectional views, isometric views, perspective views, plan views, and / or exploded illustrations that are schematic depictions of idealized embodiments and / or intermediate structures. As such, variations from the shapes of the illustrations as a result of, for example, manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments disclosed herein should not be construed as limited to the particular illustrated shapes of regions, but are to include deviations in shapes that result from, for instance, manufacturing. To this end, regions illustrated in the drawings may be schematic in nature and shapes of these regions may not reflect the actual shapes of regions of a device, and, as such, are not intended to be limiting.

[0181] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and are not to be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

[0182] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatuses of the disclosed embodiments. Accordingly, embodiments are to be considered as illustrative and not as restrictive, and embodiments are not to be limited to the details given herein. To this end, it should be appreciated that all combinations of the foregoing concepts (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the endDocket No. OPUSP047WOof this disclosure are contemplated as being part of the subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

[0183] It is to be further understood that the above disclosure, while focusing on a particular example implementation or implementations, is not limited to only the discussed example, but may also apply to similar variants and mechanisms as well, and such similar variants and mechanisms are also considered to be within the scope of this disclosure. For the avoidance of any doubt, it is also to be understood that the above disclosure is at least directed to the following numbered implementations, as well as to other implementations that are evident from the above disclosure.

Claims

1. Docket No. OPUSP047WOCLAIMSWhat is claimed is:

1. An assembly for C0xelectrolysis, the assembly comprising:a membrane electrode assembly (“MEA”) having an MEA outer edge;a first rigid MEA support frame having a first body with a first annulus shape that extends around and defines a first opening, a first top surface having a first recess adjacent to the first opening, and extending around and radially outwards of the first opening, and a first bottom surface opposite the first top surface;a second rigid MEA support frame having a second body with a second annulus shape that extends around and defines a second opening, a second top surface, and a second bottom surface opposite the first top surface; anda first seal, wherein:the first top surface faces the second bottom surface,the first rigid MEA support frame is connected to the second MEA support frame,the MEA is interposed between the first rigid MEA support frame and the second MEA support frame,the MEA outer edge is positioned within the first recess, andthe first seal:extends around and is radially offset from the first opening and the second opening, andis interposed between the first rigid MEA support frame and the second MEA support frame.

2. The assembly of claim 1, wherein the first seal is in contact with the second bottom surface and interposed between the MEA and the second rigid MEA support frame.

3. The assembly of claim 2, further comprising a second seal that:extends around and is radially offset from the first rectangular hole and the second rectangular hole,is in contact with the MEA and the first recess, andis interposed between the MEA and the first rigid MEA support frame.Docket No. OPUSP047WO4. The assembly of claim 1, further comprising a third seal that:extends around and is radially offset from the first recess,is interposed between the first rigid MEA support frame and the second MEA support frame, andis in contact with the first top surface and the second bottom surface.

5. The assembly of claim 1, further comprising a cathode gas diffusion layer (GDL), wherein:the GDL is interposed between the first rigid MEA support frame and the second MEA support frame, andthe MEA is in direct contact with the GDL.

6. The assembly of claim 5, wherein:the GDL has a GDL outer edge, andthe MEA outer edge is radially outwards of the GDL outer edge.

7. The assembly of claim 6, wherein:the first rigid MEA support frame has a second recess adjacent to the first recess and the first opening, and extending around and radially outwards of the first opening, and the GDL outer edge is positioned in the second recess.

8. The assembly of claim 6, wherein:the second rigid MEA support frame has a second recess adjacent to the second opening, and extending around and radially outwards of the second opening, andthe GDL outer edge is positioned in the second recess.

9. The assembly of claim 1, further comprising an anode porous transport layer (PTL), wherein:the PTL is interposed between the first rigid MEA support frame and the second MEA support frame, andthe MEA is in direct contact with the PTL.Docket No. OPUSP047WO10. The assembly of claim 9, wherein:the PTL has a PTL outer edge, andthe MEA outer edge is radially outwards of the PTL outer edge.

11. The assembly of claim 10, wherein:the first rigid MEA support frame has a second recess adjacent to the first recess and the first opening, and extending around and radially outwards of the first opening, and the PTL outer edge is positioned in the second recess.

12. The assembly of claim 10, wherein:the second rigid MEA support frame has a second recess adjacent to the second opening, and extending around and radially outwards of the second opening, andthe PTL outer edge is positioned in the second recess.

13. The assembly of claim 1, further comprising:a cathode gas diffusion layer (GDL) having a GDL outer edge; andan anode porous transport layer (PTL) having a PTL outer edge, wherein:the GDL and the PTL are interposed between the first rigid MEA support frame and the second MEA support frame,the MEA is interposed between the GDL and the PTL, andthe MEA outer edge is radially outwards of the GDL outer edge and PTL outer edge.

14. The assembly of claim 13, wherein:the first rigid MEA support frame has a second recess adjacent to the first recess and the first opening, and extending around and radially offset from the first opening,the second rigid MEA support frame has a third recess adjacent to the second opening, and extending around and radially outwards of the second opening,the GDL outer edge is positioned in the second recess, andthe PTL outer edge is positioned in the third recess.Docket No. OPUSP047WO15. The assembly of claim 13, wherein:the first rigid MEA support frame has a second recess adjacent to the first recess and the first opening, and extending around and radially offset from the first opening,the second rigid MEA support frame has a third recess adjacent to the second opening, and extending around and radially outwards of the second opening,the PTL outer edge is positioned in the second recess, andthe GDL outer edge is positioned in the third recess.

16. The assembly of claims 1 to 15, further comprising:a cathode frame;a cathode flow field at least partially disposed in a first opening in the cathode frame; an anode frame; andan anode flow field at least partially disposed in a second opening in the anode frame, wherein:the MEA, the first rigid MEA support frame, and the second MEA support frame are interposed between the cathode frame and the anode frame,the MEA has a cathodic part, an anodic part, and a separator between the cathodic part and the anodic part,the cathode frame is adjacent to the cathodic part,the anode frame is adjacent to the anodic part, andthe cathode frame and the anode frame are coupled to each other with a plurality of fasteners.

17. The assembly of claims 1 to 15, further comprising an anode-cathode frame having a cathode flow field at least partially disposed in an opening in the anode-cathode frame, and an anode flow field at least partially disposed in the opening, wherein:the anode-cathode frame is adjacent to the first rigid MEA support frame or the second MEA support frame,the MEA has a cathodic part, an anodic part, and a separator between the cathodic part and the anodic part, andthe cathode flow field of the anode-cathode frame is adjacent to the cathodic part of the MEA, or the anode flow field of the anode-cathode frame is adjacent to the anodic part of the MEA.Docket No. OPUSP047WO18. The assembly of claim 1, wherein the first seal is positioned in a groove of the first rigid MEA support frame or a groove of the second rigid MEA support frame.

19. The assembly of claims 1 to 15, wherein the first seal is an adhesive tape, screen printed, a dispensed seal, a sprayed seal, or a molded seal.

20. The assembly of claims 1 to 15, wherein the first opening and second opening each have a rectangular shape.

21. The assembly of claims 1 to 15, wherein the first seal has a cross-section that is circular, sawtooth, rectangular, obround, elliptical, trapezoidal, triangular, one or more semicircular portions, or a combination thereof.

22. The assembly of claim 1, wherein the first seal is not in contact with the MEA.

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