Scalable electrode flow field for water electrolyzers and method for rapid fabrication thereof

Abstract

The present disclosure provides approaches for increasing the adhesion of catalyst inks on substrates, the use of binders in the electrode ink to improve coating uniformity, incorporating pore formers in the electrode ink, approaches for growing electrodes on reinforcement layers, increasing electrochemically active surface area, and incorporating specific materials in the electrode ink. The present disclosure also relates to electrodes for electrochemical cells, including area scalable electrodes designed for rapid manufacturing. The materials, devices, and methods described herein may be applied to either or both anode or cathode electrodes for electrochemical cells.

Description

[Technical field]

[0001] INCORPORATION BY REFERENCE OF RELATED APPLICATIONS This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 63 / 299,643, filed January 14, 2022, the entire contents of which are incorporated herein by reference in their entirety.

[0002] Government support Certain embodiments of the subject matter of this application were made with United States Government support under ARPA-E Award No. DE-AR0001487. The United States Government has certain rights in the subject matter of this application.

[0003] FIELD OF THEINVENTION The present disclosure relates to approaches for increasing the adhesion of catalyst inks on substrates, the use of binders in the electrode ink to improve coating uniformity, the incorporation of pore formers in the electrode ink, approaches for growing electrodes on reinforcement layers, increasing electrochemically active surface area, and the incorporation of specific materials in the electrode ink. The present disclosure also relates to electrodes for electrochemical cells, including area scalable electrodes designed for rapid manufacturing. The materials, devices, and methods described herein may be applied to either or both anode or cathode electrodes for electrochemical cells. [Background technology]

[0004] An electrochemical cell is a device that can use electricity to induce a chemical reaction or generate electricity from a chemical reaction. When electricity is the output, the cell can be considered a fuel cell or an expander cell, depending on the chemical product. When electricity is the input, the cell can be considered an electrolyzer cell, a compressor cell, or a purifier cell, depending on the chemical product. For example, an electrolyzer takes electrical energy and stores it in a fuel, such as hydrogen, by splitting water into its components. In contrast, a fuel cell is an electrolyzer that works in the reverse direction, where hydrogen and oxygen are fed into the cell, which then combines these elements to form water, releasing electrical energy in the process. The basic elements of these devices are two electrodes, an ion-conducting electrolyte, and an ion-permeable layer that separates the two electrodes. In the case of a solid-state electrolysis cell, the ion-conducting electrolyte and the separator may be combined into an integrated solid-state ion-conducting membrane. A complete electrochemical cell may also include flow fields for delivering reactants to the electrodes, seals to isolate the reactants from each other and from the environment, and one or more impermeable separator plates, also called bipolar plates, to isolate one cell from adjacent cells in the stack and in one embodiment to contain a separate cooling fluid for thermal management of the cells.

[0005] A variety of electrolytes can be used in electrochemical cells, including proton exchange membranes, anion exchange membranes, solid oxide ceramic membranes, and liquid alkaline solutions such as potassium hydroxide and sodium hydroxide. Different electrolytes require different operating conditions, and each has its own advantages and limitations. Advantages of proton exchange membrane electrolytes and anion exchange membrane electrolytes include relatively low operating temperatures and cells that can be constructed using unitized layers of electrolyte / membrane. Electrolyzers using such membranes have distinct advantages over other electrolyzer cells that can operate using pure liquid water as the feedstock, rather than caustic solutions or water vapor, thereby greatly simplifying the balance of the system in practice.

[0006] As society's efforts to address global climate change accelerate, the need to deeply decarbonize all human energy use becomes clear and urgent. The use of hydrogen as a carbon-free energy carrier is essential to reach certain human industrial sectors that are difficult or impossible to decarbonize directly with electricity. Examples of such sectors include steel production, fertilizer manufacturing, and heavy transportation such as trucking, maritime shipping, and air transport. In addition to these sectors, hydrogen's energy density and stable storage properties make it the most promising candidate for seasonal-scale energy storage, leading to the establishment of grid resilience using only renewable electricity. This will be necessary to completely convert energy use to carbon-free sources. These and other advantages have attracted a high level of interest in the production of "green hydrogen". Hydrogen is given the "green" label when it is produced by electrolysis from renewable electricity (wind, solar, hydropower, etc.). The scale required to meet the potential demand for green hydrogen in a future global energy system is daunting. Electrolyzer production capacities will need to increase by orders of magnitude over the next decade and their costs will need to decrease by more than tenfold to meet such demand. To date, hydrogen electrolyzer manufacturing has been a niche industry with small systems based on cells and stacks designed for research and development, and limited deployment, with little consideration given to the manufacturing speeds required to manufacture and assemble the cells and stacks at a rate that meets society's ultimate needs. Summary of the Invention

[0007] One objective of the present disclosure is to overcome limitations of current electrochemical cell designs through approaches for increasing the adhesion of the catalyst ink on the substrate, the use of binders in the electrode ink to improve coating uniformity, the incorporation of pore formers in the electrode ink, approaches for growing the electrode on a reinforcing layer, increasing the electrochemically active surface area, and the incorporation of specific materials in the electrode ink.

[0008] Another object of the present disclosure is to overcome limitations of current electrochemical cell designs by providing an area scalable electrode that allows for rapid manufacturing with minimal capital costs to produce a wide range of electrolyzer cell and stack sizes.

[0009] The basic process of water electrolysis involves feeding water to a positively charged anode electrode and conducting ions between the anode and a negatively charged cathode electrode. Oxygen is produced at the anode and hydrogen is produced at the cathode. The particular ions used in the process are a function of the electrolyte selected. In an acid cell, positively charged hydronium ions are conducted from the anode to the cathode. In an alkaline cell, negatively charged hydroxide ions are conducted from the cathode to the anode. In both systems, the overall reaction is the same: (2)H2O(l) → (2)H2(g) + O2(g). Electricity must be supplied to drive the reaction. The open circuit or thermoneutral voltage for the elementary reaction of hydrogen to liquid water is 1.481V, therefore a voltage higher than 1.481V must be applied to a hydrogen electrolysis cell fed with liquid water in order for the reaction to proceed. The size of the cell (i.e., active area) determines the rate of hydrogen / oxygen production from one cell at a given applied voltage. The total current required for a particular applied voltage may be proportional to the size (i.e., active area) of the cell. In practical systems, multiple cells may be "stacked" on top of each other to increase production capacity. This stack of cells results in the need to apply a higher voltage (an integer multiple of the number of cells) to drive the reaction. For example, 1000 cm 2 The single cell is 500cm 2 It can generate the same hydrogen flow as the two stack cells, but at 500 cm 2 A stack of 10000 requires twice the voltage and 0.5 times the current input. Flexibility in selecting the required voltage and current can be an important consideration in the design and cost of the total electrolysis system. For example, a power supply for a higher current and lower voltage may be more expensive than a power supply for a higher voltage and lower current because of the size of the conductors required and the additional materials required for their construction.

[0010] As the reaction proceeds, water is consumed and hydrogen + oxygen gas is produced, so water must be continuously fed to the cell to feed the reaction. Stoichiometry is a term related to the "balance" of a chemical reaction. In an electrochemical cell, the term "stoichiometry" or "stoich" refers to the ratio of reactants fed to the cell to the amount needed to exactly balance the total reaction. For example, an electrolysis cell operating at a water stoichiometry of 2 has as its input twice the amount of water required to produce the hydrogen and oxygen exiting the cell. Conserving the mass of the system at 1 stoichiometry indicates that 1 kg of hydrogen production per hour is associated with approximately 8 kg of oxygen production per hour and approximately 9 kg of water consumption per hour. Electrolyzers can typically be operated at a minimum water stoichiometry above 1 to ensure adequate reactants everywhere in the cell. For example, when the water flow stoichiometry is 1, all of the water provided to the cell is converted to oxygen on the anode, resulting in a 100% oxygen fraction at the cell outlet (i.e., no water exits the cell). This condition may be unstable and may result in damage due to anode starvation of the cell near the outlet. It may also result in high fluid velocity and pressure loss at the outlet since everything leaving the cell is in gas phase. Thus, process conditions may be selected to maintain the oxygen vapor fraction at the cell outlet below a given threshold. For example, an outlet oxygen fraction of less than 40% may result in less than a two-fold increase in the water inlet-to-outlet flow field velocity. A water stoichiometry of 100 or more may be required to maintain an oxygen fraction of less than 40%.

[0011] The electrolysis process is not 100% efficient, and as a result, some of the input electricity is converted to heat in the cell rather than being stored as chemical energy as hydrogen. This results in a voltage greater than the thermal neutral voltage (1.481 V) required for a practical hydrogen output flow rate. The energy savings of this system are realized when the fraction of power delivered to the cell that heats up (voltage × current) is reduced by [1-(1.481 / V cellIt can be shown that the stoichiometric ratio (W / W) can be equal to [1-(1.481 / 1.8)]. A practical electrolysis cell can operate at 1.8 V, with the result that [1-(1.481 / 1.8)] = ~18% of the power is delivered to the cell and converted to heat rather than hydrogen. A practical electrolysis cell therefore requires cooling during operation, and an efficient way to achieve this cooling can be to utilize the process water itself to cool the cell. Depending on the operating conditions of the cell, a relatively high flow rate of water may be required to ensure that the peak temperature of the cell is maintained below an acceptable threshold and that the temperature gradient within the cell is also acceptable. This flow rate may also represent a water stoichiometry that is much greater than 1. For example, operating at 1.8 V and releasing 18% of the input energy to heat, the stoichiometric ratio is 2.7 W / cm 2 For a cell operating at 1000 K, a water stoichiometry of approximately 160 may be required to maintain a temperature rise across the cell of less than 10° C. From the design considerations mentioned above, the flow rate of water to the cell is dictated by the need for adequate reactants or the need for adequate temperature control, whichever is higher.

[0012] Managing the water provided to the hydrogen electrolysis cell / stack can be a major consideration for the overall hydrogen generation system. Flow rate, pressure, temperature, and composition must all be adjusted to meet the requirements of the cell / stack. A typical system includes a liquid-gas separator, heat exchanger, pump, and deionization system in a loop with the anode side of the cell / stack, allowing water to be recirculated at the required flow rate. As the system produces hydrogen and oxygen, 1 "stoichiometric" water is consumed. The consumed water can be replenished by injecting 1 stoichiometric fresh water into the system loop from a source of acceptable quality (e.g., demineralized water, desalinated water, or municipal water). Given the scale of the electrolysis plant, the required water flow consumed by the cell / stack can be proportional to the plant capacity. It may be desirable to keep other process parameters (pressure, temperature, composition) constant regardless of scale, as this can greatly simplify system component selection, overall system control, and engineering, procurement, and construction (EPC) costs at the deployment site. For example, water pumps may generally be commercially available in a wide range of scales of flow rate for a given pressure capability. It may therefore be advantageous to have a basic cell / stack where the water flow resistance is independent of the size of the cell or stack. Larger systems can then be built in a modular fashion from more cells and / or more stacks without the need to change the water pump technology and basic pressure ratings for the system and plant. [Brief description of the drawings]

[0013] The accompanying drawings are incorporated in and constitute a part of this specification. The drawings illustrate only certain embodiments of the present disclosure and, together with the above and following description, serve to explain the principles of the disclosure. Wherever possible, the same identification numbers are used throughout the different drawings to refer to common or similar components.

[0014] [Figure 1]FIG. 1 shows an isometric view of the electrolysis cell components of FIG. 3 and illustrates exemplary cross flow orientations of process fluids along the x- and y-axes, as well as the repetition of cell components along the z-axis to form a stack of cells.

[0015] [Diagram 2] FIG. 2 shows a cross-section of the electrolysis cell components in the active area of ​​a typical cell, illustrating the ion, electron and fluid flows for proton and anion exchange membrane electrolysis technology.

[0016] [Diagram 3] FIG. 3 shows an isometric view of the anode flow field components and illustrates the tradeoffs that exist when scaling the cell active area.

[0017] [Figure 4] FIG. 4 shows the mathematical model output for pressure drop versus velocity through an example flow field for water and hydrogen flows, and illustrative pressure drop target thresholds.

[0018] [Diagram 5] FIG. 5 shows test results for water flow resistance for various candidate flow fields, confirms the model results of FIG. 4 for water flow pressure drop, and illustrates alternative illustrative pressure drop target thresholds.

[0019] [Figure 6] FIG. 6 shows mathematical model output for water temperature rise versus water stoichiometric value for two exemplary cell operating voltage values ​​and illustrative water temperature rise thresholds.

[0020] [Figure 7] FIG. 7 shows the mathematical model output for outlet oxygen volume fraction versus water stoichiometric value for example cell operating pressures and illustrative oxygen volume fraction thresholds.

[0021] [Figure 8]Figure 8 shows the results of multiple tests on the mechanical strength of candidate flow fields and illustrates the percentage of the initial thickness to which the material must be calendared in order to withstand the target compressive load when assembled into a complete cell / stack.

[0022] [Figure 9] FIG. 9 illustrates the basic steps that may be included in a rapid manufacturing process for making scalable reinforced electrodes and integrated electrode flow field components.

[0023] [Figure 10] FIG. 10 shows a plan view of the process of FIG. 9 and illustrates the inherent y-axis scalability (l) of the reinforced electrode and flow field component fabrication method to achieve cells of variable active area from a fixed x-axis roll web width (w).

[0024] [Figure 11] FIG. 11 shows some illustrative examples where the surfaces of the electrodes and / or flow field substrates may be embossed or patterned to promote bonding during lamination.

[0025] [Figure 12] FIG. 12 shows a representative scanning electron microscope image of an anode electrode synthesized using the pore-former disclosed herein.

[0026] [Figure 13] FIG. 13 shows performance data measured over time for a preferred embodiment of the present invention, illustrating its superior longevity compared to the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Detailed Description of Specific Embodiments In one aspect, the present application provides embodiments of a pretreatment process that uses an adhesion promoter / primer to increase the adhesion of the catalyst ink on the substrate to create a reinforced electrode and prevent delamination. When adhesion promoters and primers are discussed in this application, embodiments that include one shall provide the other alternatively or include both in combination, when technically possible. In some embodiments, the reinforcing substrate is treated with an adhesion promoter to improve the surface adhesion of the catalyst ink. These adhesion promoters may include one or more self-assembled monolayers of aliphatic phosphonic acids, silanes, alkylthiols, or similar materials. The adhesion promoter may include conductive adhesives, such as Electrodag: Bonderite S-FN EB012 Acheson, Henkel's Loctite™, or similar materials. In some embodiments, the surface roughness of the electrode reinforcing material may be modified by treating with agents that change the surface tension, such as surfactants (anionic, cationic, amphoteric surfactants), including 3M Fluorosurfactant FC-4430 or similar materials. The adhesion promoter may be in liquid form and may be coated directly onto the substrate, or may be deposited using chemical vapor deposition techniques.

[0028] The present application also provides embodiments that include a binder in the electrode ink recipe to improve coating uniformity and electrode integrity. The electrode ink can include one or more non-ionic polymer binders, such as PTFE, PVA, PAA, PVDF, SBR, SEBS, or similar materials. The electrode ink can include an ionic polymer binder that contains cationic protons or anionic hydroxide ions. The electrode ink layer can contain a surface tension modifier, such as a surfactant, a fluorosurfactant, a silicone surfactant, a siloxane, or similar material. Quaternized polyvinyl alcohol can be used as an additive binder. The electrode ink layer may also contain an adhesion promoter, such as an epoxy.

[0029] The present application also provides embodiments incorporating pore formers in the electrode ink to promote pore formation, thereby providing an efficient path for water to reach the active reaction sites of the electrode and allowing evolved gas to easily exit the active reaction sites throughout the electrode. The electrode ink may include a pore former that promotes pore formation in the final reinforced electrode layer. The formed pores can reduce mass transport limitations and promote effective bubble removal in the area scalable reinforced anode electrodes of the present invention. The pore formers may include one or more of ammonium bicarbonate, ammonium carbonate, sodium carbonate, sodium bicarbonate, or similar materials. The pore formers may include one or more leavening agents, such as air, water vapor, yeast, baking soda, baking powder, poly(methyl methacrylate), wheat particles, poppy seeds, sawdust, carbon fiber, graphite, or similar materials.

[0030] In a preferred embodiment, the pore-former may include ammonium bicarbonate.

[0031] The present application also provides an embodiment in which the electrode may be grown directly on the reinforcing layer by processing procedures such as hydrothermal deposition, electrodeposition, room condition deposition, or similar processes. The electrode layer may contain one or more of platinum, molybdenum, nickel, cobalt, boron, cerium, iron, tin, sulfur, phosphorus, fluorine, oxygen, hydroxides, or similar materials. The electrode may be supported on a conductive support such as carbon (Vulcan, Ketjen Black, etc.), nickel, iron, titanium, stainless steel, or combinations of these materials. In a preferred embodiment, the electrode includes iron and nickel in oxide form (NiFe2O4) using a reinforcing substrate of nickel foam or nickel felt. In another preferred embodiment, the electrode includes Pt and carbon using either a reinforcing layer of nickel foam, nickel felt, or carbon fiber.

[0032] More specifically, metal foams, felts, sintered parts, or other porous metal substrates can be functionalized to serve as electrodes for water electrolyzers and / or fuel cells. The functionalized electrodes enable high speed and efficiency of desired electrochemical reactions in the fuel cell electrolyzer by enabling superior reaction kinetics due to inherent catalytic activity and superior conductivity to fluids, electrons, and ions.

[0033] In certain embodiments of the present disclosure, the effective electrochemically active surface area ("ECSA") of the porous substrate is increased, providing more reaction sites compared to the unmodified substrate, thus increasing system performance. Thus, in certain embodiments, this is achieved by subjecting the porous (or non-porous) substrate to an alloying step, in which the added or alloyed material reacts with and deposits on the surface of the porous substrate, such that the atoms of the substrate and the added material are mixed in the surface region. This is followed by a dealloying step, in which the added or alloyed material is again removed. In one example, this can be achieved by alloying (galvanizing) stainless steel or nickel with zinc in a liquid zinc bath for a few seconds to a few hours, and then removing the zinc in a potassium hydroxide bath or another medium that dissolves the zinc from the alloy. Here, the porous substrate is characterized by a high degree of surface roughness due to nano- and micro-scale grooves and pores left by the added and later removed material, corresponding to a high effective ECSA. Based on the above, one skilled in the art will appreciate that other alloying / dealloying steps are possible depending on the choice of material base and alloying materials, and the present application is intended to encompass such other base and alloying materials.

[0034] In other embodiments, the increase in ECSA can be achieved by deposition or electrodeposition of the material onto a substrate without subsequent removal. In other embodiments, the increase in ECSA can be achieved by deposition or electrodeposition of the material onto a substrate, followed by a heat treatment to induce alloying in the material, followed by a dealloying step.

[0035] In certain embodiments of the present application, an additional material (such as Pt, Ir, Ni, Fe, Mo, and other materials) is optionally deposited on the high ECSA porous substrate described in the previous paragraph. This material is catalytically active for the desired reaction, either inherently or due to interactions with the substrate material, changes that occur in response to reaction conditions in the electrolyzer and / or fuel cell, or other reasons. In other embodiments, the additional material is not deposited on the high ECSA porous substrate, but is introduced in ionic form into the working fluid of the electrolyzer or fuel cell, and thus the surface deposition relative to the concentration of the additional material in solution determines the surface concentration.

[0036] The present application also provides an embodiment in which an ionomer may be used in the electrode ink formulation. The ionomer may include a poly(arylpiperidinium)-based polymer consisting of either piperidone monomers or 3-oxo-6-azoniaspiro[5,5]undecane salt monomers, an aromatic, and optionally a trifluoroacetophenone monomer group. The ionomer may include a styrene-butadiene block copolymer (SEBS)-based ionomer or polymer with a quaternary ammonium group tethered through an aromatic ring. The ionomer may include a multi-block copolymer including one or more norbornene-based hydrophilic blocks and one or more norbornene-based or alkene-based hydrophobic blocks. The ionomer may include a trimethyl or benzyltrimethylammonium-functionalized polystyrene ionomer with different mole percentages of quaternized benzylammonium. The ionomer may include a hexamethyltrimethylammonium-functionalized Diels-Alder polyphenylene (HTMA-DAPP). The ionomers can include ionomers that use tetrakis(dialkylamino)phosphonium cations as functional groups. The ionomers can include polyethylene-based triblock copolymers, polychloromethylstyrene-b-polyethylene-b-polychloromethylstyrene (PCMS-b-PE-b-PCMS) quaternized with either trimethylammonium or methylpiperidinium cations. The ionomers can include ionomers or polymers that include cationic benzimidazolium or imidazolium-containing moieties. The ionomers can include ionomers based on hexamethyl-p-terphenyl poly(benzimidazolium). The ionomers can include ionomers or polymers with 3M-PFSA (EW798) precursors that contain copolymers of tetrafluoroethylene (PTFE) and trifluoroethylene functionalized with perfluorinated sulfonyl fluorocarbon chains. The ionomers can include PPN (polyphenylene) ionomers and / or PAP (polyarylpiperidinium) ionomers.

[0037] In a preferred embodiment, the electrode ink comprises a poly(arylpiperidinium) based polymer consisting of either piperidone monomers or 3-oxo-6-azoniaspiro[5,5]undecane salt monomers, an aromatic, and optionally a trifluoroacetophenone monomer group.

[0038] In another preferred embodiment, the electrode ink comprises a copolymer comprising one or more norbornene-based hydrophilic monomers and one or more norbornene-based or alkene-based hydrophobic monomers. The polymer can be a block copolymer as well as a random copolymer.

[0039] In another preferred embodiment, the electrode ink comprises a polymer based on styrene-butadiene block copolymer (SEBS) having quaternary ammonium groups tethered through aromatic rings.

[0040] The present invention provides an embodiment in which a catalytic material is used in the electrode formulation. The anode catalytic material is RuO2, IrO2, spinel oxides, e.g. Al 0.5 Mn 2.5 O4, PbRuO x , Fe x Ni y OOH, IrRuO2, Perovskite, Mo (direct deposition), MoP, IrO x / NbO x , IrRuO2 / NbO x , NiFeCo, NiCe@NiFe / NF, Fe-CoP / NF, Co3O4, Co2O3, Fe 0.33 Co 0.66 P, Fe(PO3)2 / Ni2P, (Ni,Fe)OOH, Ni-Fe-OH@Ni3S2 / NF, Ni(Fe)O x H y , Ni x Fe y , Ni y Fe (1-y) O x , Co x Fe 3-xO4 / CFP, where x is (0, 0.1,..., 2.0, 2.1,...) and y is (0, 0.1,..., 2.0, 2.1,...). These catalytic materials can be in the form of nanoparticles or nanowires that may or may not be supported on a conductive support. In some embodiments, the anode catalyst can include a catalytic promoter such as cerium oxide or a similar material. The cathode catalytic material can be Ni x Mo y , Pt / C, Pt alloy / ECS, Pt / ECS, Pt black, Pt alloy, Ni alloy, NiZn, NiMo, MoS2 / Ni3S2 / NF, a-MoS x / CC, Co-Co2P@NPC / rGO, Ni 2(1-x) Mo 2x P / NF, Co 2.90 B 0.73 P 0.27 The catalyst materials may include one or more of the following: F-Co2P / Fe2P / IF, Ni2P / NF, CoP / Ni5P4 / CoP, P-Fe3O4 / IF, A-NiCo LDH / NF, where ECS stands for engineered catalyst support. These catalyst materials may be in the form of nanoparticles or nanowires that may or may not be supported on a conductive support.

[0041] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure, as claimed.

[0042] In yet another embodiment of the present disclosure, the scalable electrode provides substantially equal resistance to water flow, equal temperature rise, and equal outlet oxygen fraction at a given operating voltage regardless of the selected active area. A preferred embodiment of the disclosed electrode may be substantially rectangular and is characterized by a dimension along the x-axis selected based on the roll web width (w) of the electrode reinforcement and / or flow field material used in its manufacture. The desired roll web width (w) can be selected based on maintaining process parameters for the operating electrode within target thresholds. For example, it may be desirable to keep the water pressure drop through the electrode below pumping pressure limits of the system, stack, and cell in which the electrode may be installed. Alternatively, it may be desirable to maintain the water flow temperature rise below the limits of the stack, cell, or electrode temperature gradient to ensure acceptable performance and life. Alternatively, it may be desirable to maintain the electrode outlet oxygen volume fraction below a limit that ensures stable performance and life of the cell. Alternatively, the desired roll web width (w) may be selected based on available raw materials for constructing the electrode reinforcement. For example, it may be desirable to select a roll web width (w) that minimizes waste material in converting rolls to parts during assembly. In this case, the desired roll web widths (w) for the electrodes and flow fields may be the same or different. If they are different, the selected roll web width (w) may be selected based on the most expensive of the electrode reinforcement or flow field, and the other roll of material may be selected with a web width (w) that matches that first one, this matching meaning the roll web width (w) that optimizes production speed and / or overall cost.

[0043] Variable active area can be achieved from the scalable electrodes of the present disclosure by adjusting the length of the anode electrode along the y-axis. Water can then be distributed parallel to the y-axis along the leading edge of the anode flow field adjacent the electrode using manifolds, distribution windows, plenums and / or other features within the cell. The leading edge of the anode flow field can be defined as the edge where water enters the flow field. The length of the anode flow field along the y-axis can be selected to keep the water velocity along the x-axis at the leading edge of the anode flow field below a predetermined threshold. The total length of the electrode along the y-axis can then determine the electrode active area and can be selected to achieve an overall target hydrogen production rate for the cell. The y-axis dimension and flow field thickness can then be selected to maintain the water flow pressure loss, water temperature rise and / or oxygen outlet volume fraction below target thresholds.

[0044] The scalable electrode of the present disclosure can include one or more electrode reinforcement substrates of a desired roll web width along the x-axis and can be selected from the group consisting of foam, felt, woven screen, expanded metal, and sintered metal frit. The one or more flow field substrates of a desired roll web width along the x-axis can be selected from one or more of foam, felt, woven screen, expanded metal, and sintered metal frit. The scalable electrode can also include an active electrode material coated, printed, or otherwise attached onto the electrode reinforcement substrate. The scalable electrode can also include conversion of the electrode reinforcement substrate to an active electrode material by a chemical, physical, or thermal process.

[0045] In another embodiment, a method for producing an area-scalable reinforced electrode is described. The electrode reinforcement substrate of the desired roll web width along the x-axis can be selected from the group consisting of foam, felt, woven screen, expanded metal, and sintered metal frit. The electrode reinforcement substrate material from one or more rolls can be directed along the y-axis through a calendering roller configured to achieve the desired thickness of the electrode reinforcement substrate and the desired surface properties on each side and / or to laminate multiple layers together. For example, the calendering rollers disposed on each side of the substrate web can be of the same or different diameters, or they can be of the same or different materials. It may be advantageous to use a harder and / or smaller roll on the side of the electrode reinforcement substrate to be converted to an active electrode to achieve a denser and / or smoother surface for conversion. It may also be advantageous to use a softer and / or larger roll on the side of the electrode reinforcement substrate to be laminated to a flow field substrate to maintain a more porous and / or rougher surface for lamination.

[0046] The electrode backing substrate may be converted into an active electrode by appropriate processing. For example, the electrode material may be spray coated, screen printed, rotary screen printed, doctor blade coated, slot die coated, curtain coated, squeegee coated, or laminated using heat and / or pressure onto a suitable surface of the electrode backing substrate. The electrode conversion process may also include post-coating steps. For example, the coating may be dried, heat treated, annealed, or otherwise physically or chemically treated to promote bonding to the substrate and / or functional performance of the electrode.

[0047] The flow field substrate of the desired roll web width along the x-axis can be selected from the group consisting of foam, felt, woven screen, expanded metal, sintered metal frit, and combinations thereof. The flow field substrate material from one or more rolls can be directed along the y-axis through a calendering roller configured to achieve the desired thickness, relative density, strength, and / or surface properties of the flow field and / or to laminate multiple layers of substrate together. For example, the calendering rollers located on each side of the substrate web can be of the same or different diameters, or they can be of the same or different materials. It can also be advantageous to use a softer and / or larger roll on the side of the flow field substrate to be laminated to the electrode reinforcement substrate to maintain a more porous and / or rougher surface for lamination.

[0048] These flow fields are usually called porous transport layers or gas diffusion layers. In certain embodiments of the present disclosure, they are made of titanium, aluminum, carbon (e.g., carbon paper, carbon fiber composite, graphite felt, graphene, carbon cloth, etc.), nickel, copper, zinc, stainless steel (e.g., SS304, SS316, SS316L, SS430, SSA-286, etc.), other materials, or combinations thereof. They may be coated or uncoated, wet-proofed (to increase their hydrophobicity), and may include a microporous layer (to improve water repellency and improve catalyst adhesion). In some embodiments, the gas diffusion layer has a nanostructure or microstructure. In some embodiments, the gas diffusion layer is formed of nanowires, microfibers, or cloth. Those skilled in the art will understand that the embodiments of the present application can be combined such that they are used together. Further objects, features, and advantages of the present application will become apparent from the detailed description of the preferred embodiments set forth below, when considered in conjunction with the drawings.

[0049] Detailed Description of the Drawings A detailed description of the drawings will now be given with reference to the accompanying drawings. Although the following description is primarily directed to electrolysis, it will be understood by those skilled in the art that the described features, components and methods are applicable and adaptable to other electrochemical technologies, including hydrogen compressors, hydrogen purifiers, CO2 electrolyzers, chlorine electrolyzers, etc. Those skilled in the art will understand that the subject matter described in the previous embodiments (e.g., relating to approaches for increasing adhesion of the catalyst ink on the substrate, using binders in the electrode ink to improve coating uniformity, incorporating pore formers in the electrode ink, approaches for growing electrodes on the reinforcing layer, increasing electrochemically active surface area, and incorporating certain materials in the electrode ink) may be applied to the embodiments described in the drawings.

[0050] FIG. 1 shows an isometric view of an electrolyzer (101) illustrating exemplary cross flow orientations (103) and (104) of process fluids, as well as the repetition of cell components (105) along the z-axis (102) to form a stack of cells. Here, a bipolar plate (106) can be seen separating one cell of thickness (107) from an adjacent cell (105). Water and oxygen (103) can flow along the x-axis within a composite anode electrode flow field (111) of thickness (108). Hydrogen (104) can flow along the y-axis within a composite cathode electrode flow field (109) of thickness (110). Assuming the cell is oriented as shown with the gravity vector pointing downward and parallel to the z-axis, it may be advantageous to place the anode above the membrane as shown to create a buoyancy force to help move oxygen bubbles formed on the anode electrode into the water flowing through the anode flow field above the anode electrode.

[0051] FIG. 2 shows a cross-section of an exemplary core electrolysis cell component (201) in the active area of ​​the cell and illustrates typical ion, electron and fluid flows for proton (212) and anion (213) exchange membrane electrolysis technology, where (208) is an impermeable separator, or bipolar, plate, (205) is the cathode flow field, (207) is the cathode electrode, (204) is the ion conducting membrane, (206) is the anode electrode, and (203) is the anode flow field. When a power source is attached to the cell, which has a negative electrode (209) at the bottom and a positive electrode (210) at the top, electrons (211) can flow upward through the cell. If the cell is acidic proton conducting (212), positive hydronium ions can be induced to migrate downward through the membrane (204) by the resulting electric field. If the cell is of alkaline hydroxide conduction type (213), the negative hydroxide ions can be induced to migrate upward through the membrane (204) by the resulting electric field. In both types, hydrogen can be formed on the cathode (207) and flow into the cathode flow field (205), while oxygen can be formed on the anode (206) and flow into the anode flow field (203). In dry cathode systems, water may be provided only to the anode flow field (203) as a reactant to form hydrogen and oxygen. Stoichiometry is a term relating to the "balance" of a chemical reaction. In electrochemical cells, the term "stoichiometry" or "stoichiometry" refers to the ratio of reactants provided to the cell to the amount needed to exactly balance the total reaction. As previously described herein, the water stoichiometry provided to the anode flow field (203) may be much higher than 1. Also, because the fluid in the anode flow field (203) may be mostly liquid, this section may represent a significant flow resistance compared to the cathode flow field. The thickness of the cathode flow field (214) and the anode flow field (215) may affect the flow rate, temperature distribution, and pressure loss within the cell. The overall cell pitch (216) of the cell may be determined by the thickness of each of the components (203)-(208) that make up the complete cell.A small cell pitch (216) may be desirable to produce an electrolyzer stack with high power density and small size for a given hydrogen production rate [kg / hr]. Therefore, optimizing the anode flow field geometry (length in the water flow direction along the x-axis, width along the y-axis, and thickness along the z-axis) may be an important design goal for the electrolyzer. For example, the anode (203) and / or cathode (205) flow fields may be configured with thicknesses of 0.1-5.0 mm, 0.2-3.0 mm, 0.3-2 mm, 0.5-2 mm, or 0.6-2 mm. The flow fields (203) and (205) may be selected with the same or different thicknesses based on factors to optimize cell process conditions, performance, and manufacturing.

[0052] FIG. 3 shows an isometric view (301) of the anode electrode flow field components (306) and illustrates the tradeoffs that may exist when scaling the cell area. The anode flow field may have a width "w" (305) along the x-axis, a length "l" (304) along the y-axis, and a thickness "t" (303) along the z-axis. The width "w" (305) along the x-axis may be 5-1000 cm, 5-500 cm, 5-100 cm, or 10-50 cm. The length "l" (304) along the y-axis may be 1-5000 cm, 5-3000 cm, 10-1000 cm, or 25-1000 cm. The active area (307) may be found by multiplying the width "w" (305) by the length "l" (304). The water flow area at the leading edge (308) can be found by multiplying the thickness "t" (303) by the length "l" (304). The water flow for a fixed stoichiometry and efficiency (309) into this water flow area (308) can be determined by the area (307). To achieve higher hydrogen production [kg / hr] at a fixed efficiency and water stoichiometry, additional area "dA" (311a) and / or (311b) can be required. If "dA" (311b) is created by adding "dw" (310b) to "w" (305), additional water (313b) can be required to enter the fixed leading edge flow area (308). The added water flow can thereby increase the water flow velocity through the flow field, resulting in an increased pressure drop (314). If "dA" (311a) is created by adding "dl" (310a) to "l" (304), the additional water (313a) may be accompanied by a proportional increase in the fixed leading edge flow area (312a). The added water may flow through the incrementally proportional flow area (312a) without increasing the pressure drop (314). Thus, the scaling area along the y-axis may allow all process conditions such as pressure, temperature and oxygen volume fraction within the electrode to remain constant. The total water flow rate may necessarily be proportional to the hydrogen / oxygen production rate, while other system parameters may be unchanged by scaling the electrode only along the y-axis. This may greatly simplify the resulting electrolyzer system made from electrodes designed in this way.For example, electrolyzer production plant specifications, including pressure ratings, temperature ratings, and / or fluid composition ratings, can be consistent for plants with different water flows and hydrogen / oxygen capacities, which in turn can simplify engineering procurement and construction activities, expand the available supply of system components, and reduce overall hydrogen production costs.

[0053] FIG. 4 shows mathematical model results (431) for pressure drop [mbar / cm] per unit flow length (414) as a function of flow velocity (409) [cm / s] for hydrogen gas (432) and liquid water (433) flowing through a typical porous medium that may be used for the anode and / or cathode flow fields. Also shown is an illustrative target pressure drop threshold (434) that may be selected based on the overall electrolyzer stack and system design. The threshold (434) represents an upper limit for water pressure drop, thereby defining a target threshold for water velocity in the anode flow field (435). As is evident from the results (431), the pressure drop per unit length for hydrogen can be several times smaller than for water at a given velocity. Therefore, as the cell area increases, it may be advantageous to prioritize electrode scaling based on water velocity and flow length. For example, a water pump for supplying water to an electrolysis cell may have a pressure capability of up to 10 bar. It may be advantageous to configure the anode flow field (401) such that water velocities (409) of less than 100 cm / s, less than 50 cm / s, less than 20 cm / s, less than 10 cm / s, or less than 5 cm / s remain within the capabilities of commonly available system water pumps.

[0054] Figure 5 shows test results (561) for pressure drop [mbar / cm] per unit flow length (514) as a function of flow velocity (509) [cm / s] for liquid water flowing through several potential porous media that may be used for the anode and / or cathode flow fields. The mathematical model results from Figure 4 (533) are repeated for reference, along with an illustrative target pressure drop threshold (534) that may be selected based on the overall electrolyzer stack and system design. The threshold (534) may represent an upper limit for water pressure drop, thereby defining a target threshold for water velocity in the anode flow field (535) for these actual potential flow field candidates (Samples 1-8).

[0055] FIG. 6 shows mathematical model results (641) for the water temperature rise (615) [°C] as a function of the stoichiometric value of the supplied water. The heat released during electrolyzer operation may be a function of efficiency, which in turn may be a function of the operating cell voltage. Saving energy for the cell may result in an expression for the water temperature rise as specified in Equation 6c-1 (below), where V is the cell voltage, V0 is the thermoneutral cell voltage [1.25 V], LHV is the low heating value of hydrogen [120 MJ / kg], c p is the specific heat capacity of water [4.182 kJ / kg°C], and St is the stoichiometry of the water supplied to the cell. Plots (642) and (643) show the results of this model at two possible operating voltages, representing example values ​​for the beginning of life [BoL] and end of life [EoL] of an electrolysis cell. Also shown is an illustrative water temperature rise target threshold (644), above which the anode electrode may not operate stably or durable, or above which the electrolysis cell, stack or system may not operate efficiently. The temperature rise threshold can be used in conjunction with the EoL voltage limit to define a lower water stoichiometry threshold (645). It can be advantageous to select the water stoichiometry to keep the water temperature rise at the end of life below 100°C, below 50°C, below 25°C, below 15°C, or below 10°C to maintain stable and durable operation of the electrodes.

[0056] Formula 6c-1:

number

[0057] FIG. 7 shows the mathematical model results (751) for the oxygen volume fraction at the anode flow field outlet (752) as a function of the stoichiometric value of the supplied water. The process of electrolysis splits water into hydrogen on the cathode side and oxygen on the anode side. Once oxygen is formed on the anode, it can mix as a gas with the delivered liquid water, resulting in a two-phase flow in the anode flow field. The volume fraction of oxygen at the anode outlet can be indicative of the operational stability, performance, and / or durability of the electrode, and a target threshold for this parameter can be set by the designer. Conserving mass for the cell can result in an expression for the oxygen outlet volume fraction as specified in Equation 7d-1, where r O2 is the density of oxygen gas at the anode outlet, and r H2O is the density of the liquid water at the anode outlet, and St is the stoichiometry of the water fed to the cell. Plot (752) shows the results of this model at 10 bara pressure at the anode electrode along with an illustrative oxygen volume fraction threshold (754) above which the electrode may not operate stably or durable or above which the electrolytic cell, stack or system may not operate efficiently. The oxygen volume fraction threshold can be used to identify a lower threshold water stoichiometry (755). To maintain stable and durable operation of the electrodes, it may be advantageous to select the water stoichiometry to maintain the oxygen volume fraction below 80%, below 60%, below 50%, below 40% or below 30%.

[0058] Formula 7d-1:

number

[0059] FIG. 8 shows measured strength data (861) for several samples of candidate electrode reinforcement materials, illustrating the permanent change in thickness (809) as a function of mechanical exposure stress (814). The curve represents the material yield strength as a function of deformed thickness. During assembly of the electrolysis stack, a compressive load is applied to the active area to maintain sufficient contact and low contact resistance between layers in the cells and between individual cells in the stack. The compressive load applied during assembly may be greater than the expected internal fluid pressure of the stack to ensure that the cells or cell components do not separate during operation. To ensure that this contact is maintained, it is desirable to maintain the elastic behavior of the cells and cell components. As indicated by limits (834) and (835), it may be advantageous to permanently deform the electrode reinforcements to a value less than X% of their initial thickness to ensure that they remain elastic. For the candidate materials tested, x=40%, however, the specific value for any candidate electrode reinforcement material may be greater or less than 40% based on the particular properties and material characteristics of that candidate, including porosity, basis weight (defined as mass per unit area in the xy plane), material of construction, and porous shape (e.g., foam, mesh, expanded metal, felt, or other).

[0060] FIG. 9 shows basic steps in a rapid manufacturing process (901) for making reinforced electrodes and flow field components (913). One or more rolls of porous substrate (903a) can be selected based on the desired roll web width "w" (915), as previously described. The substrate may include foam, felt, woven screen, expanded metal, sintered frit, or fiber cloth or paper. The substrate selected may have a porosity of up to 98%, where porosity is defined as the volume percent of the substrate available for fluid flow therethrough. For example, the porosity may be 98%-40%, 95%-50%, 90%-60%, or 95%-80%. The composition of the substrate may include iron, nickel, chromium, steel, stainless steel, Inconel, aluminum, titanium, carbon, or combinations thereof. The substrate may be plated or coated with other materials, such as platinum, gold, tin, carbon, titanium nitride, PTFE, or another corrosion-inhibiting layer, including engineered layers of polymeric or oxide materials with conductive metal or carbon pathways. The roll (903a) may be loaded onto an unwinding station designed to hold the web flat under known surface tension and allow it to move along the y-axis (902). The roll (903a) may be calendered through a set of rollers (904) and (905) to laminate two or more layers together, reduce the porosity of the web, reduce or increase its thickness, increase its strength, increase its stiffness, and / or create desired surface properties on one or both sides of the web (906). For example, the substrate may be advantageously relatively smooth on one side and rough on the other side to facilitate later steps in the process. It may also be advantageous to achieve a porosity gradient through the thickness of the substrate. For example, it may be beneficial for downstream processes for one side of the calendered substrate (906) to be of relatively low porosity to accommodate conversion to an electrode, while the opposite side of (906) to be of relatively high porosity to facilitate bonding with a second substrate.To achieve different properties on each side of the web (906), the rollers (904) and (905) may be of the same or different diameters, and / or may be made of the same or different materials, and / or may be constructed with different surface finishes or coatings, and / or may be provided with specific surface patterns that may be embossed on one or both sides of the rolled web (903a). The calendered reinforcement substrate (906) may then be converted into an electrode (908) in a manner (907) described in the embodiments described in this disclosure. For example, the electrode material may be spray coated, screen printed, rotary screen printed, doctor blade coated, slot die coated, curtain coated, squeegee coated, or laminated as a film, decal, or solid layer using heat and / or pressure onto the appropriate surface of the electrode substrate (906). The electrode conversion process (907) may also include post-coating steps. For example, the coating may be dried, heat treated, annealed, and / or otherwise physically or chemically treated to promote bonding to the substrate and / or electrochemical performance of the cell. The conversion process (907) may also include a chemical or physical vapor deposition process for conversion to an active electrode (908). The conversion process (907) may also include a plasma or flame spray process (906) for depositing the electrode material on the substrate (906) or for chemically reacting and / or converting it to an active electrode. Following the process (907), the electrode web (908) may be placed adjacent to one or more additional rolls of porous substrate (903b). These substrates may be the same as the electrode substrate (903a) or different, and may be selected based on a similar range of possible materials and properties as (903a), but to meet functional requirements for the fluid flow field rather than electrode reinforcement. For example, making (903b) the same as (903a) may result in the highest purchase volume and lowest supply costs. Selecting (903b) from a substrate different from (903a) may be advantageous for cell performance (electrical resistance, flow resistance, thermal conductivity, mechanical elasticity, or mechanical strength).In process step (910), the electrode web (908) may be laminated to the flow field web (909) by a suitable lamination process. The lamination process (910) may include mechanical rolling or calendering through rollers similar to (904) and (905) to facilitate co-infiltration of solid fibers, membranes or wires from web (908) into web (909). To achieve this mechanical bonding, the similar rollers (904) and (905) may be of the same or different diameters and / or made of the same or different materials and / or may be configured with different surface finishes or coatings and / or may include specific surface patterns. It may be advantageous to select (903a) and (903b) from the same feedstock, but to pre-calender and / or laminate multiple layers of (903b) prior to the lamination step (910). The pre-calendering / lamination step may include embossing a pattern on the side of (909) that is to be co-infiltrated with (908) to facilitate mechanical bonding. The lamination process (910) may also include other steps, including heat treatment or application of bonding promoters, such as adhesives, polymeric suspensions, liquid ionomers or ionomer suspensions, to one or more of the webs (908) and (909). The order of steps (907) and (910) may be reversed such that conversion of the web (906) to an electrode (908) may occur after lamination to the web (909). Certain electrode materials and / or methods may be advantageously formed only after calendaring and lamination to ensure that adequate adhesion is maintained in the final web (911). In some cases, the electrodes may be coated onto a membrane, in which case the conversion step (907) may be omitted in the process (901). Following the lamination step (910), the unitized electrode flow field web (911) may be processed (912) to create individual pieces (913) of appropriate size for integration into an electrolysis cell (915). For example, the web (911) may be treated in step (912) by punching with a knife or other cutting die to ensure accurate sizing of the component pieces.In some cases, laminating the web (908) to the web (909) can occur after the cutting step (912). The exact size of the part (913) can depend on whether an anodic or cathodic electrode flow field is to be produced. The overall process (901) can be adapted to produce either an anodic or cathodic electrode / flow field as desired, and the specific materials, coatings, steps and settings of the line can be the same or different for each. In production, one anodic electrode / flow field and one cathodic electrode / flow field can be produced simultaneously by using two independent lines to allow for rapid production of a complete electrolytic cell.

[0061] Figure 10 shows a top view (xy plane) of the process described in Figure 9. The explanatory labels have been kept the same between the figures. The area scalability of the present invention is illustrated by the variable length die cutting step (912) which results in variable area electrode part pieces (913) by changing only the length (1009) of the part. The process (901) has the advantage that the capital equipment required to manufacture electrodes of varying active area is roll with fixed handling width (915) while achieving consistent operating conditions for electrodes of various sizes as described in Figures 3-7.

[0062] 11 shows some schematic examples of patterning or embossing of electrodes and / or flow field substrates to promote enhanced bonding during the lamination step of process (901). The patterns can be linear along the y-axis as shown at (1121) and (1122), along the x-axis (not shown), or along both the x-axis and y-axis in a cross-hatch style (1123) and (1124). The depth and spacing of the profile shapes (triangles (1121), rectangles (1122), or other shapes (not shown)) can be optimized based on the materials and other properties of the substrates being laminated.

[0063] FIG. 12 shows a scanning electron microscope image of an electrode synthesized according to a preferred embodiment of the present invention using a bicarbonate pore former, illustrating the macro- and micro-porosity of the resulting electrode structure.

[0064] Figure 13 shows the current at 0.5A / cm 2 Performance data (1301) of cell voltage (1304) as a function of operating time (1305) measured on a cell operating at 1000 C and 60° C., using a NiFe2O4 anode electrode synthesized and fabricated on a nickel foam reinforcement layer according to a preferred embodiment of the present invention. The data shows durable operation for over 330 hours without catalyst separation or spillage. For comparison, published data (1302) [ACS Appl. Mater. Interfaces 2021, 13, 44, 51917-51924, https: / / pubs.acs.org / doi / 10.1021 / acsami.1c06053] was overlaid, showing larger decay rates and inferior lifetimes for three competing systems (1303) at comparable operating conditions compared to the present invention (1301).

[0065] Further embodiments: A-1. active electrode material, A reinforcing substrate, and 1. An electrode for an electrochemical cell, comprising a flow field, comprising: the open flow field includes a first layer including a material selected from the group consisting of foam, felt, woven screen, expanded metal, and sintered metal frit and having a desired rolled web width along an x-axis; the reinforcing substrate comprises a material selected from the group consisting of foam, felt, woven screen, expanded metal, and sintered metal frit; and a second layer having a desired rolled web width along the x-axis; The flow field thickness along the z-axis and the flow field length along the y-axis are independently adjustable, producing a variable cell active area that maintains water flow resistance, water temperature rise or cell outlet oxygen volume fraction below a target threshold for the electrode. A-2. The thickness and length are selected to achieve a water flow velocity at the leading edge of the flow field of less than 100 cm / s, or the thickness and length are selected to achieve a water flow pressure drop of less than 5 bar between the leading edge and the training edge of the flow field when operating at rated conditions and hydrogen production capacity. The electrode described in A-1. A-3. The open flow field includes a multi-layer stack; The electrode according to A-1 to A-2. A-4. The thickness of the combination of the reinforcement electrode and the flow field is less than 3 mm, preferably less than 2 mm, and most preferably less than 1 mm; Electrodes A-1 to A-3. A-5. The water temperature rise is less than 50℃. The electrode according to claims A-1 to A-4. A-6. The outlet oxygen volume fraction is less than 95%; The electrode according to claims A-1 to A-5. A-7. The active electrode material is bonded to the reinforcing substrate with an adhesion promoter selected from the group consisting of adhesives, polymer dispersions, liquid ionomers, ionomer dispersions, and mixtures thereof; The electrode according to A-1 to A-6. A-8. The bonding promoter is PTFE, which is incorporated into the electrode ink during synthesis. The electrode according to A-1 to A-7. A-9. The active electrode material contains a foaming agent selected from the group consisting of ammonium bicarbonate, ammonium carbonate, sodium carbonate, sodium bicarbonate, air, water vapor, yeast, baking soda, baking powder, and mixtures thereof; The electrode according to A-1 to A-8. A-10. The active electrode material and flow field comprises at least one of carbon, nickel, titanium, iron, chromium, stainless steel or Inconel; The electrode according to A-1 to A-9. A-11. The electrode reinforcement substrate and flow field include one or more nickel foam layers; The electrode according to A-1 to A-10. A-12. The porosity, basis weight, number of layers and final laminate thickness of the flow field are selected so as not to yield during assembly, compression and operation of the cell; The electrode according to A-1 to A-11. A-13. The yield strength achieved is 5kgf / cm 2 Greater than 10kgf / cm 2 Greater than 15kgf / cm 2 Greater than 25kgf / cm 2 Greater than The electrode according to A-1 to A-12. A-14. one or more of the electrode reinforcement substrate and the flow field substrate include a roughened, patterned, or embossed surface to facilitate lamination; The electrode according to claims A-1 to A-13. B-1. 1. A method of manufacturing an integrated electrode flow field for a scalable electrolysis cell, comprising: forming an open flow field through lamination or calendaring of one or more layers of a desired roll web width along the x-axis and a desired thickness along the z-axis, the layers being selected from the group consisting of foam, felt, woven screen, expanded metal, and sintered metal frit; cutting the open flow field into separate pieces corresponding to desired lengths along the y-axis; forming an electrode reinforcement substrate through lamination and / or calendaring of one or more layers selected from the group consisting of foam, felt, woven screen, expanded metal, and sintered metal frit having a desired roll web width along the x-axis and a desired thickness along the z-axis; converting the formed electrode reinforcement substrate into an active reinforced electrode; cutting the active reinforced electrode web into separate pieces having a desired length along the y-axis; and A method comprising positioning open flow field and active reinforced electrode components adjacent to one another such that the resulting assembly achieves a desired cell active area while maintaining one or more of water flow resistance or water temperature rise or cell outlet oxygen volume fraction below target electrode thresholds. B-2. The thickness and length are selected to achieve a water flow velocity at the leading edge of the flow field of less than 100 cm / s. The method described in B-1. B-3. The thickness and length are selected to achieve a water flow pressure drop of less than 5 bar between the leading edge and training edge of the electrode flow field when operating at rated conditions and hydrogen production capacity. The methods according to B-1 to B-2. B-4. The thickness of the combination of the reinforcement electrode and the flow field is less than 3 mm, preferably less than 2 mm, and most preferably less than 1 mm; The methods according to B-1 to B-3. B-5. The water temperature rise is less than 50℃. The methods according to B-1 to B-4. B-6. The outlet oxygen volume fraction is less than 95%; The methods according to B-1 to B-5. B-7. The flow field webs and the reinforcing electrode webs are laminated before being cut into separate pieces. The methods according to B-1 to B-6. B-8. The electrode substrate and the flow field substrate comprise at least one of carbon, nickel, titanium, iron, chromium, stainless steel, or Inconel; The methods described in B-1 to B-7. B-9. One or more of the reinforcing electrode web and the flow field web are processed to create a roughened, patterned, or embossed surface to facilitate lamination; The methods according to B-1 to B-8. B-10. the laminating step includes a bonding promoter selected from the group consisting of adhesives, polymer dispersions, liquid ionomers and ionomer dispersions; The methods described in B-1 to B-9. B-11 The reinforcing material is 100g / m 2 and 1000g / m 2 and one or more nickel foam layers having a basis weight between The methods according to B-1 to B-10. B-12. The electrode conversion of the electrode reinforcement substrate is performed prior to lamination to the flow field web; The methods according to B-1 to B-11. B-13. The electrode conversion of the electrode reinforcement substrate is performed after lamination to the flow field web; The methods according to B-1 to B-12. B-14. The reinforced electrodes and flow fields are stacked on the assembly within the electrolysis cell. The methods according to B-1 to B-13. B-15. The porosity, basis weight, number of layers and final laminate thickness of the flow field are selected so as not to yield during assembly, compression and operation of the cell; The methods according to B-1 to B-14. B-16. The yield strength is 5kgf / cm 2 Greater than 10kgf / cm 2 Greater than 15kgf / cm 2 Greater than 25kgf / cm 2 Greater than The methods according to B-1 to B-15. C-1. 1. A method for increasing the effective electrochemically active surface area of ​​a substrate, comprising: Alloying the substrate with an alloying material to incorporate the alloying material into a surface of the substrate; subsequently dealloying the substrate to remove the alloy material; or C-2. The substrate is porous; The method described in C-1. C-3. 1. A method for increasing the effective electrochemically active surface area of ​​a substrate, comprising: A method that involves the deposition or electrodeposition of a material onto a substrate such that the added material creates a higher surface roughness. C-4. applying a heat treatment to induce alloying of the materials, followed by dealloying the substrate to remove the alloyed materials; The method described in C-3. C-5. further comprising depositing or electrodepositing an additional catalytic material onto the substrate. The methods according to C-1 to C-4. C-6. further comprising introducing into the working fluid an ionic material that deposits on the electrochemically active surface area and increases the catalytic activity of the surface. The methods according to C-1 to C-5. D-1. 1. A method for increasing adhesion of a catalyst ink onto a substrate, comprising: A method comprising treating a substrate with an adhesion promoter: Here, the adhesion promoter is selected from the group consisting of (a) self-assembled monolayers of aliphatic phosphonic acids, silanes, alkylthiols or similar materials, (b) conductive adhesives such as Electrodag: Bonderite S-FN EB012 Acheson or similar materials, and (c) mixtures thereof. D-2. further comprising modifying the surface roughness of the substrate, the surface roughness being modified by treating the surface with an agent that alters surface tension, such as a surfactant, including 3M Fluorosurfactant FC-4430 or a similar material; The method described in D-1. D-3. The substrate is an electrode. The method according to D-1 to D-2. E-1. An electrode ink for coating an electrode, comprising: An electrode ink that includes a binder or pore former. E-2. The binder is selected from the group consisting of PTFE, PVA, PAA, PVDF, SBR, SEBS and similar materials; The electrode ink according to E-1. E-3. The binder is an ionic polymeric binder containing cationic protons or anionic hydroxide ions; The electrode ink according to E-1 to E-2. E-4. Further comprising a surface tension modifying agent, the surface tension modifying agent being selected from the group consisting of surfactants, fluorosurfactants, silicone surfactants, siloxanes, and similar materials; The electrode ink according to E-1 to E-3. E-5. Further comprising quaternized polyvinyl alcohol, The electrode ink according to any one of E-1 to E-4. E-6. The pore former is selected from the group consisting of ammonium bicarbonate, ammonium carbonate, sodium carbonate, sodium bicarbonate, similar materials, and mixtures thereof; The electrode ink according to E-1 to E-5. E-7. The pore former is a leavening agent, the leavening agent being selected from the group consisting of air, water vapor, yeast, baking soda, baking powder, similar materials, and mixtures thereof; The electrode ink according to any one of E-1 to E-6. F-1. 1. A method of manufacturing an electrode, comprising the steps of: A method of manufacture comprising growing an electrode on the reinforcing layer via hydrothermal deposition, electrodeposition, room condition deposition, or a similar process. F-2. The electrodes may be made of any of a variety of metals, including platinum, molybdenum, nickel, cobalt, boron, cerium, iron, tin, sulfur, phosphorus, fluorine, oxygen, hydroxides, similar materials, or mixtures thereof; The method described in F-1. F-3. The electrodes are supported on a conductive support, the conductive support comprising carbon (Vulcan, Ketjen Black, etc.), nickel, iron, titanium, stainless steel, or a combination of these materials; The methods described in F-1 to F-2. F-4. The electrodes contain nickel iron oxide (NiFe2O4) The reinforcing layer comprises nickel foam or nickel felt; The methods described in F-1 to F-3. F-5. The electrode comprises Pt and carbon; The reinforcing layer includes a nickel foam, nickel felt or carbon fiber reinforcing layer; The methods described in F-1 to F-4.

[0066] The foregoing description has been presented for purposes of illustration and description only. It is not intended to be exhaustive or to limit the application to the precise form disclosed, but modifications and variations are possible and / or may be obvious in light of the above teachings or may be acquired from the practice of the application. The embodiments have been chosen and described in order to explain the principles of the application and its practical application, and to enable those skilled in the art to utilize the application in various embodiments and with various modifications as may be suited to the particular uses contemplated. It is intended that the scope of any published patent be defined by the claims appended hereto. [Explanation of symbols]

[0067] 101 Electrolyzer 102 Axis 103 Water and Oxygen 104 Hydrogen 105 Cell Components 106 Bipolar Plate 107, 108, 110 Thickness 109 Cathode Electrode Flow Field 111 Anode Electrode Flow Field 203 Anode flow field 204 Ion Conductive Membrane 205 Cathode flow field 206 Anode Electrode 207 Cathode Electrode 208 Impermeable separator 209 Negative electrode 210 Positive electrode 216 Cell Pitch 307 Active region 308 Water flow area

Claims

1. 1. A method for increasing the effective electrochemically active surface area of ​​a substrate, comprising: (a) alloying a substrate with an alloying material to incorporate the alloying material into a surface of the substrate; and subsequently dealloying the substrate to remove the alloy material; or (b) Deposition or electrodeposition of material onto a substrate such that the added material creates a higher surface roughness; The method includes:

2. The substrate is porous; The method of claim 1.

3. (b), further comprising applying a heat treatment to induce alloying of the materials, followed by dealloying the substrate to remove the alloyed materials. The method of claim 1.

4. further comprising depositing or electrodepositing an additional catalytic material onto the substrate. The method according to any one of claims 1 to 3.

5. further comprising introducing into the working fluid an ionic material that deposits on the electrochemically active surface area and increases the catalytic activity of the surface. The method according to any one of claims 1 to 4.

6. 1. A method for increasing adhesion of a catalyst ink onto a substrate, comprising: A method comprising treating a substrate with an adhesion promoter: Here, the adhesion promoter is selected from the group consisting of (a) self-assembled monolayers of aliphatic phosphonic acids, silanes, alkylthiols or similar materials, (b) conductive adhesives such as Electrodag: Bonderite S-FN EB012 Acheson or similar materials, and (c) mixtures thereof.

7. further comprising modifying the surface roughness of the substrate, the surface roughness being modified by treating the surface with an agent that alters surface tension, such as a surfactant, including 3M Fluorosurfactant FC-4430 or a similar material; The method according to claim 6.

8. The substrate is an electrode. The method according to claim 6.

9. An electrode ink for coating an electrode, comprising: An electrode ink that includes a binder or pore former.

10. The binder is selected from the group consisting of PTFE, PVA, PAA, PVDF, SBR, SEBS and similar materials; The electrode ink according to claim 9.

11. The binder is an ionic polymeric binder containing cationic protons or anionic hydroxide ions; The electrode ink according to claim 10.

12. Further comprising a surface tension modifying agent, the surface tension modifying agent being selected from the group consisting of surfactants, fluorosurfactants, silicone surfactants, siloxanes, and similar materials; The electrode ink according to any one of claims 9 to 100.

13. Further comprising quaternized polyvinyl alcohol, The electrode ink according to any one of claims 9 to 12.

14. The pore former is selected from the group consisting of ammonium bicarbonate, ammonium carbonate, sodium carbonate, sodium bicarbonate, similar materials, and mixtures thereof; The electrode ink according to claim 9.

15. The pore former is a leavening agent, the leavening agent being selected from the group consisting of air, water vapor, yeast, baking soda, baking powder, similar materials, and mixtures thereof; The electrode ink according to claim 9.

16. 1. A method of manufacturing an electrode, comprising the steps of: A method of manufacture comprising growing an electrode on the reinforcing layer via hydrothermal deposition, electrodeposition, room condition deposition, or a similar process.

17. The electrodes may be made of any of a variety of metals, including platinum, molybdenum, nickel, cobalt, boron, cerium, iron, tin, sulfur, phosphorus, fluorine, oxygen, hydroxides, similar materials, or mixtures thereof; 17. The method of claim 16.

18. The electrodes are supported on a conductive support; The conductive support may be made of any of a variety of materials, including carbon (Vulcan, Ketjen Black, etc.), nickel, iron, titanium, stainless steel, or combinations of these materials. The method according to any one of claims 16 to 17.

19. The electrodes are nickel iron oxide (NiFe ２ O ４ ), The reinforcing layer comprises nickel foam or nickel felt; The method according to any one of claims 16 to 18.

20. the electrode comprises Pt and carbon; The reinforcing layer includes a nickel foam, nickel felt or carbon fiber reinforcing layer; The method according to any one of claims 16 to 18.

Images