Membrane-electrode assembly for water electrolysis cell, and water electrolysis cell comprising same

Abstract

Provided is a membrane-electrode assembly for a water electrolysis cell, comprising: a polymer electrolyte membrane having an active area and an inactive area surrounding the active area; a hydrogen generation electrode positioned on a first surface of the active area of the polymer electrolyte membrane; an oxygen generation electrode positioned on a second surface of the active area of the polymer electrolyte membrane; a first sub-gasket which is disposed on a first surface of the inactive area of the polymer electrolyte membrane and which surrounds a first electrode; and a second sub-gasket which is disposed on a second surface of the inactive area of the polymer electrolyte membrane and which surrounds a second electrode, wherein the first sub-gasket has a first window that accommodates the hydrogen generation electrode, and a first water supply path that surrounds the first window and exposes the inactive area of the polymer electrolyte membrane.

Description

Membrane-electrode assembly for electrolysis cell and electrolysis cell including same

[0001] The present disclosure relates to a membrane-electrode assembly for a water electrolysis cell and a water electrolysis cell including the same.

[0002] With the growing demand for alternative energy sources to replace fossil fuels, interest is growing in energy conversion and storage systems that are highly efficient, inexpensive, and environmentally friendly. Fuel production through water electrolysis, with its high potential for commercialization, is attracting significant attention as a key alternative that addresses environmental and energy concerns. Water electrolysis is a technology that electrochemically decomposes water to produce hydrogen and oxygen.

[0003] Among them, in a polymer electrolyte membrane water electrolysis cell (PEMWE), the membrane electrode assembly (MEA) that actually generates hydrogen has a structure in which an oxygen evolution reaction electrode, which is an electrode where an oxygen evolution reaction (OER) occurs, and a hydrogen evolution reaction electrode, where a hydrogen evolution reaction (HER) occurs, are positioned with a polymer electrolyte membrane containing a cation-conducting polymer or an anion-conducting polymer interposed therebetween.

[0004] In a polymer electrolyte membrane electrolysis cell, the oxygen evolution electrode is in contact with water and the hydrogen evolution electrode is not separately humidified, so the water content of the polymer electrolyte membrane has a concentration gradient in the thickness direction.

[0005] As the moisture content of a polymer electrolyte membrane increases, its ionic conductivity also increases. Therefore, polymer electrolyte membrane electrolysis cells face limitations due to the low moisture content of the hydrogen-generating electrode. Furthermore, polymer electrolyte membrane electrolysis cells can generate heat when operated at high currents or voltages, making temperature control difficult.

[0006] One aspect of the present disclosure is to provide a membrane-electrode assembly for a water electrolysis cell, which can maximize the performance of the water electrolysis cell by directly supplying water to the polymer electrolyte membrane, thereby increasing the water content of the polymer electrolyte membrane, thereby improving the ionic conductivity of the polymer electrolyte membrane, and additionally reducing the energy required by cooling the membrane-electrode assembly.

[0007] A membrane-electrode assembly for a water electrolysis cell according to one aspect comprises: a polymer electrolyte membrane having an active area and an inactive area surrounding the active area; a hydrogen evolution electrode positioned on a first side of the active area of ​​the polymer electrolyte membrane; an oxygen evolution electrode positioned on a second side of the active area of ​​the polymer electrolyte membrane; a first sub-gasket positioned on the first side of the inactive area of ​​the polymer electrolyte membrane and surrounding the first electrode; and a second sub-gasket positioned on the second side of the inactive area of ​​the polymer electrolyte membrane and surrounding the second electrode; wherein the first sub-gasket has a first window accommodating the hydrogen evolution electrode, and a first water supply path surrounding the first window and exposing the inactive area of ​​the polymer electrolyte membrane.

[0008] The first window can penetrate the first sub-gasket to expose the hydrogen generation electrode.

[0009] The first water supply path can penetrate the first sub-gasket to expose the inactive region of the polymer electrolyte membrane.

[0010] The first window and the first water supply path may be vacant holes.

[0011] The first water supply path may be extended to surround all four sides of the first window.

[0012] One end of the first water supply path may be spaced apart from the other without meeting.

[0013] The second sub-gasket may have a second window that accommodates an oxygen generating electrode.

[0014] It may not have a water supply path that exposes the inactive region of the polymer electrolyte membrane.

[0015] The oxygen evolution electrode may include a noble metal oxide catalyst including iridium oxide, an oxide of an iridium alloy, or a combination thereof.

[0016] The membrane-electrode assembly for the electrolysis cell may further include a first gas diffusion layer positioned over the hydrogen evolution electrode; and a second gas diffusion layer positioned over the oxygen evolution electrode.

[0017] The first gas diffusion layer may include an electrically conductive porous member including carbon paper, carbon cloth, carbon felt, metal paper, metal cloth, metal felt, or a combination thereof.

[0018] The second gas diffusion layer comprises a plurality of fibers integrated in a form including a plurality of pores, and the plurality of fibers may comprise a metal oxide or a metal.

[0019] The membrane-electrode assembly for the electrolysis cell may further include a first gasket disposed over the first sub-gasket and surrounding the first gas diffusion layer; and a second gasket disposed over the second sub-gasket and surrounding the second gas diffusion layer.

[0020] The first gasket may have a third window accommodating the first gas diffusion layer, and a third water supply path surrounding the third window and exposing the first water supply path of the first gas diffusion layer.

[0021] A water electrolysis cell according to one aspect comprises: the above-described membrane-electrode assembly; a first separator positioned on a first side of the membrane-electrode assembly; and a second separator positioned on a second side of the membrane-electrode assembly; wherein the first separator has a flow channel positioned in an area corresponding to a hydrogen generation electrode, and a water channel surrounding the first flow channel and positioned in an area corresponding to a first water supply path.

[0022] The water channel can be extended to surround all four sides of the flow channel.

[0023] One end of the water channel may be spaced apart from the other without meeting.

[0024] One end of the water channel may have a water inlet.

[0025] The other end of the water channel may have a water outlet.

[0026] The area ratio of the water channel to the total area of ​​the first separator can be from 10% to 80%.

[0027] The ratio of the depth of the water channel to the total thickness of the first separator can be from 5% to 40%.

[0028] The electrolysis cell may further include a first gas diffusion layer positioned over the hydrogen evolution electrode; and a second gas diffusion layer positioned over the oxygen evolution electrode.

[0029] The second gas diffusion layer comprises a plurality of fibers integrated in a form including a plurality of pores, and the plurality of fibers may comprise a metal oxide or a metal.

[0030] The electrolytic cell may further include a first gasket disposed on the first sub-gasket and surrounding the first gas diffusion layer; and a second gasket disposed on the second sub-gasket and surrounding the second gas diffusion layer.

[0031] The first gasket may have a third window accommodating the first gas diffusion layer, and a third water supply path surrounding the third window and exposing the first water supply path of the first gas diffusion layer.

[0032] A membrane-electrode assembly for a water electrolysis cell according to one aspect can improve the ionic conductivity of a polymer electrolyte membrane by directly supplying water to the polymer electrolyte membrane, thereby increasing the moisture content of the polymer electrolyte membrane, and additionally maximize the performance of the water electrolysis cell by cooling the membrane-electrode assembly to reduce the required energy.

[0033] FIG. 1 is a cross-sectional view of a membrane-electrode assembly according to one embodiment.

[0034] Figure 2 is a plan view of the membrane-electrode assembly according to Figure 1.

[0035] FIG. 3 is a cross-sectional view of a membrane-electrode assembly according to one embodiment.

[0036] Figure 4 is a plan view of the membrane-electrode assembly according to Figure 3.

[0037] FIG. 5 is a cross-sectional view of a membrane-electrode assembly according to one embodiment.

[0038] Figure 6 is a plan view of the membrane-electrode assembly according to Figure 5.

[0039] Fig. 7 is a cross-sectional view of a water electrolysis cell according to one embodiment.

[0040] Figure 8 is a plan view of the separator illustrated in Figure 7, showing the surface facing the membrane-electrode assembly.

[0041] The advantages and features of the technology described below, as well as the methods for achieving them, will become clearer with reference to the detailed implementation examples described below together with the accompanying drawings. However, the form of implementation may not be limited to the implementation examples disclosed below. Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning that can be commonly understood by those of ordinary skill in the relevant technical field. In addition, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined.

[0042] Throughout the specification, whenever a part is said to “include” a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. However, the embodiments described below are presented for illustrative purposes only to facilitate a clear understanding of the present disclosure and do not limit the scope of the present disclosure.

[0044] Fig. 1 is a cross-sectional view of a membrane-electrode assembly according to one embodiment. Fig. 2 is a plan view of the membrane-electrode assembly according to Fig. 1.

[0045] Referring to FIGS. 1 and 2, a membrane-electrode assembly for a water electrolysis cell includes a polymer electrolyte membrane (110), a hydrogen generation electrode (121) positioned on a first surface of the polymer electrolyte membrane (110), an oxygen generation electrode (122) positioned on a second surface (the surface opposite the first surface) of the polymer electrolyte membrane (110), a first sub-gasket (131) positioned on the first surface of the polymer electrolyte membrane (110), and a second sub-gasket (132) positioned on the second surface of the polymer electrolyte membrane (110).

[0046] For example, the polymer electrolyte membrane (110) may include a porous support including a plurality of pores and an ion conductor filling the internal pores of the porous support.

[0047] The porous support may comprise, as an example, a highly fluorinated polymer, for example, a perfluorinated polymer, which has excellent resistance to thermal and chemical degradation. For example, the porous support may comprise polytetrafluoroethylene (PTFE) or a polymer composed of tetrafluoroethylene and CF2=CFC. n F 2n+1 (n is an integer from 1 to 5) or CF2=CFO-(CF2CF(CF3)O) m C n F 2n+1 (m is an integer from 0 to 15, and n is an integer from 1 to 15) may be a copolymer.

[0048] As an example of a porous support, the porous support may be a nonwoven fibrous web composed of a plurality of randomly oriented fibers.

[0049] A nonwoven fibrous web is a sheet having a structure of individual fibers or filaments that are interlaid, but not in the same manner as a woven fabric. A nonwoven fibrous web can be manufactured by methods including carding, garnetting, air-laying, wet-laying, melt-blowing, spunbonding, or stitch bonding.

[0050] As another example of a porous support in the form of a nonwoven fibrous web, the porous support may include a nanoweb in which nanofibers are aggregated in the form of a nonwoven fabric containing a large number of pores.

[0051] Nanofibers can be made of hydrocarbon polymers that exhibit excellent chemical resistance and have hydrophobic properties, so there is no concern about shape deformation due to moisture in a high-humidity environment. For example, hydrocarbon polymers may include nylon, polyimide, polyaramid, polyetherimide, polyacrylonitrile, polyaniline, polyethylene oxide, polyethylene naphthalate, polybutylene terephthalate, styrene butadiene rubber, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyvinylidene fluoride, polyvinyl butylene, polyurethane, polybenzoxazole, polybenzimidazole, polyamideimide, polyethylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, copolymers thereof, or combinations thereof, and among these, polyimide, which has superior heat resistance, chemical resistance, and shape stability, can be used.

[0052] The porosity of the porous support may be 45% or more, for example, 60% or more. On the other hand, the porous support may have a porosity of 90% or less. If the porosity of the porous support exceeds 90%, the shape stability may deteriorate, so that the post-process may not proceed smoothly. The porosity can be calculated by the ratio of the air volume to the total volume of the porous support according to the following mathematical equation 1. At this time, the total volume is calculated by manufacturing a rectangular sample and measuring the width, length, and thickness, and the air volume can be obtained by measuring the mass of the sample, then subtracting the polymer volume calculated inversely from the density from the total volume.

[0053] [Mathematical Formula 1]

[0054] Porosity (%) = (air volume in porous support / total volume of porous support) X 100

[0055] For example, the polymer electrolyte membrane (110) may be a polymer electrolyte membrane (110) in the form of a reinforced composite membrane in which an ion conductor is filled in the internal pores of a porous support.

[0056] At this time, the polymer electrolyte membrane (110) may further include a first ion conductor layer positioned on one side of the porous support and a second ion conductor layer positioned on the other side of the porous support. The first ion conductor layer and the second ion conductor layer may be formed by the ion conductor remaining after filling the internal pores of the porous support to form a thin film on the surface of the porous support.

[0057] The ionic conductor may comprise a main chain, side chains branched from the main chain, and ion exchange groups substituted on the side chains.

[0058] For example, the ion conductor may include a cation exchange group. That is, the polymer electrolyte membrane (110) may be applied to a proton exchange membrane water electrolysis (PEMWE) cell.

[0059] In the cation exchange membrane electrolysis cell, water is supplied toward the oxygen generation electrode (122), and hydrogen ions (H) are produced through the polymer electrolyte membrane (110). + ) is moved toward the hydrogen generation electrode (121).

[0060] For example, the cation exchange group included in the ion conductor may include a sulfonic acid group, an ethylbenzene sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, a sulfonic acid fluoride group, or a combination thereof, and may be, for example, a sulfonic acid group.

[0061] For example, the main chain of the ion conductor containing the cation exchange group may be selected from the group consisting of poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), poly(tetrafluoroethylene), fluorinated polyarylene, polyimide (PI), polyarylethersulfone (PAES), polyaryletherketone, polyetheretherketone (PEEK), polybenzimidazole (PBI), polysulfone (PSU), polystyrene (PS), polyphosphazene, polyquinoxaline, polyketone, polyether sulfone, polyether ketone, polyphenylene sulfone, polyphenylene sulfide, It may include polyphenylene sulfide sulfone, polyphenylene sulfide sulfone nitrile, polyarylene ether, polyarylene ether nitrile, polyarylene ether ether nitrile, polyarylene ether sulfone ketone, polyethylene, polyphenylene ether, polypyrrole, polythiophene, polycarbazole, polyaniline, polyindole, polypyrrole, or a combination thereof.

[0062] For example, the ionic conductor may include an anion exchange group. That is, the polymer electrolyte membrane (110) may be applied to an anion exchange membrane water electrolysis (AEMWE) cell.

[0063] In the anion exchange membrane electrolysis cell, water is supplied to the hydrogen generation electrode (121) and hydroxide ions (OH) are produced through the polymer electrolyte membrane (110). - ) is moved toward the oxygen generating electrode (122).

[0064] For example, the anion exchange group included in the ion conductor may include an ammonium group, a pyridine group, a triazole group, a tetraalkylammonium group, an imidazolium group, a benzimidazolium group, a cyclic ammonium group, or a combination thereof, and may be, for example, an ammonium group.

[0065] For example, the main chain of the ion conductor including an anion exchange group may include polyphenylene oxide, polyphenylene, polyfluorene, poly(aryl piperidinium), polynorbornene, polystyrene (PS), polybenzimidazole (PBI), polyphenylene sulfide, polysulfone (PSU), polyaryletherketone, polyethylene, polyphenylene ether, polypyrrole, polythiophene, polycarbazole, polyaniline, polyindole, polypyrrole, or a combination thereof.

[0066] The hydrogen generation electrode (121) and the oxygen generation electrode (122) are aligned with each other with a polymer electrolyte membrane (110) between them, and the polymer electrolyte membrane (110) has an active region that transfers cations or anions between the hydrogen generation electrode (121) and the oxygen generation electrode (122) and an inactive region (110a) surrounding it.

[0067] For example, the active region of the polymer electrolyte membrane (110) may be a region in contact with the hydrogen generation electrode (121) and the oxygen generation electrode (122), and the inactive region (110a) may be a region not in contact with the hydrogen generation electrode (121) and the oxygen generation electrode (122).

[0068] The hydrogen generation electrode (121) may be placed on the first side of the active area of ​​the polymer electrolyte membrane (110), and the oxygen generation electrode (122) may be placed on the second side of the active area of ​​the polymer electrolyte membrane (110).

[0069] The hydrogen generation electrode (121) and the oxygen generation electrode (122) may each include a catalyst layer.

[0070] For example, the catalyst layer may include a noble metal oxide. The noble metal oxide may be iridium oxide, an oxide of an iridium alloy, or a combination thereof. For example, the noble metal oxide may be IrO x (x is an integer from 1 to 3), IrMO x (M includes Ru, Pt, Sn, Se, Zn, Au, Te, Nb, or a combination thereof, and x is an integer from 1 to 3) or a combination thereof.

[0071] For example, the catalyst layer may include a precious metal, and the precious metal may be a platinum-based precious metal. For example, the platinum-based precious metal may include platinum (Pt) and / or a Pt-M alloy. M may include palladium (Pd), ruthenium (Ru), iridium (Ir), osmium (Os), gallium (Ga), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), silver (Ag), gold (Au), zinc (Zn), tin (Sn), molybdenum (Mo), tungsten (W), lanthanum (La), or rhodium (Rh). For example, Pt-M alloys include Pt-Pd, Pt-Sn, Pt-Mo, Pt-Cr, Pt-W, Pt-Ru, Pt-Ni, Pt-Co, Pt-Y, Pt-Ru-W, Pt-Ru-Ni, Pt-Ru-Mo, Pt-Ru-Rh-Ni, Pt-Ru-Sn-W, Pt-Ru-Ir-Ni, Pt-Co-Mn, Pt-Co-Ni, Pt-Co-Fe, Pt-Co-Ir, Pt-Co-S, Pt-Co-P, Pt-Fe, Pt-Fe-Ir, Pt-Fe-S, Pt-Fe-P, Pt-Au-Co, Pt-Au-Fe, Pt-Au-Ni, Pt-Ni, Pt-Ni-Ir, Pt-Cr, Pt-Cr-Ir, or these May include combinations.

[0072] For example, the catalyst layer of the hydrogen generation electrode (121) may include a noble metal, and the noble metal may include a platinum-based noble metal. The catalyst layer of the oxygen generation electrode (122) may include a noble metal oxide, and the noble metal oxide may include iridium oxide, an oxide of an iridium alloy, or a combination thereof.

[0073] The catalyst layer may further include a noble metal oxide or a carrier supporting the noble metal. The carrier supporting the noble metal oxide may be, for example, titanium dioxide (TiO2). The carrier for supporting the precious metal may be a carbon-based carrier, and for example, the carbon-based carrier may include graphite, super P, carbon fiber, carbon sheet, carbon black, Ketjen Black, Denka black, acetylene black, carbon nanotube (CNT), carbon sphere, carbon ribbon, fullerene, activated carbon, carbon nanofiber, carbon nanowire, carbon nanoball, carbon nanohorn, carbon nanocage, carbon nanoring, ordered nano- / meso-porous carbon, carbon aerogel, mesoporous carbon, graphene, stabilized carbon, activated carbon, or a combination thereof.

[0074] The catalyst layer may further include an ion conductor to enhance adhesion and facilitate hydrogen ion transport. The description of the ion conductor that may be included in the catalyst layer is the same as that described for the polymer electrolyte membrane (110), and thus, a repeated description is omitted. The ion conductor included in the catalyst layer and the ion conductor included in the polymer electrolyte membrane (110) may be the same or different.

[0075] The first sub-gasket (131) may be placed on the first surface of the inactive region (110a) of the polymer electrolyte membrane (110), and the second sub-gasket (132) may be placed on the second surface of the inactive region (110a) of the polymer electrolyte membrane (110).

[0076] The first and second sub-gaskets (131, 132) can prevent damage to the edge portion of the polymer electrolyte membrane (110) due to repeated swelling and shrinkage during operation of the electrolysis cell, improve the poor handling of the membrane-electrode assembly due to the extremely thin polymer electrolyte membrane (110), and prevent leakage of fluid, for example, hydrogen gas or oxygen gas.

[0077] Each of the first and second sub-gaskets (131, 132) has a first and a second window to accommodate the hydrogen generation electrode (121) and the oxygen generation electrode (122), and expose the hydrogen generation electrode (121) and the oxygen generation electrode (122). For example, the first window may be a hole positioned at the center of the first sub-gasket (131) and penetrating the first sub-gasket (131) in the thickness direction. In addition, the second window may be a hole positioned at the center of the second sub-gasket (132) and penetrating the second sub-gasket (132) in the thickness direction. That is, the first and second windows may be vacant holes.

[0078] In other words, when the surface of the first sub-gasket (131) facing the hydrogen generation electrode (121) is referred to as the first surface, and the surface opposite the first surface is referred to as the second surface, the hydrogen generation electrode (121) penetrates the first surface and the second surface of the first sub-gasket (131), and the hydrogen generation electrode (121) can be exposed to the second surface of the first sub-gasket (131). In addition, when the surface of the second sub-gasket (132) facing the oxygen generation electrode (122) is referred to as the first surface, and the surface opposite the first surface is referred to as the second surface, the oxygen generation electrode (122) penetrates the first surface and the second surface of the second sub-gasket (132), and the oxygen generation electrode (122) can be exposed to the second surface of the second sub-gasket (132). The first sub-gasket (131) can surround the hydrogen generation electrode (121), and the second sub-gasket (132) can surround the oxygen generation electrode (122).

[0079] The first sub-gasket (131) has a first water supply path (P11) corresponding to the inactive region (110a) of the polymer electrolyte membrane (110). In other words, the first water supply path (P11) of the first sub-gasket (131) can overlap with the inactive region (110a) of the polymer electrolyte membrane (110) in the thickness direction.

[0080] For example, on the plane of the first sub-gasket (131), the first water supply path (P11) may be located in an area corresponding to the inactive area (110a) of the polymer electrolyte membrane (110). The first water supply path (P11) may be located at a predetermined distance from the first window and may surround the first window. For example, the first water supply path (P11) may extend to surround four sides of the first window. However, one end and the other end of the first water supply path (P11) may not meet but may be spaced apart from each other. Accordingly, the first sub-gasket (131) may have a single configuration in which the first window portion and the first water supply path (P11) portion are not separated but connected.

[0081] The first water supply path (P11) may be a hole penetrating the first sub-gasket (131) in the thickness direction. That is, the first water supply path (P11) may be a vacant hole. Accordingly, the inactive region (110a) of the polymer electrolyte membrane (110) may be exposed to the second surface of the first sub-gasket (131) through the first water supply path (P11) of the first sub-gasket (131).

[0082] During operation of the electrolysis cell or during the activation process of the polymer electrolyte membrane (100), water is supplied to the first water supply path (P11), which is an empty hole, and water flows along the first water supply path (P11).

[0083] When water reaches the inactive region (110a) of the polymer electrolyte membrane (110) through the first water supply path (P11) of the first sub-gasket (131), a difference in water concentration occurs between the inactive region (110a) and the active region of the polymer electrolyte membrane (110). As a result, water flows from the inactive region (110a) to the active region according to Fick's law of diffusion, which states that water flows from a region of high water concentration to a region of low water concentration. By directly supplying water to the polymer electrolyte membrane (110), the moisture content of the polymer electrolyte membrane (110) is increased, thereby improving the ionic conductivity of the polymer electrolyte membrane (110), and additionally, the membrane-electrode assembly is cooled to reduce the required energy, thereby maximizing the performance of the water electrolysis cell.

[0084] Meanwhile, the second sub-gasket (132) does not have a water supply path corresponding to the inactive region (110a) of the polymer electrolyte membrane (110).

[0085] For example, on the plane of the second sub-gasket (132), the area corresponding to the inactive area (110a) of the polymer electrolyte membrane (110) does not have a water supply path and is blocked by the second sub-gasket (132). Therefore, the inactive area (110a) of the polymer electrolyte membrane (110) is not exposed to the second surface of the second sub-gasket (132).

[0086] Since the oxygen generation electrode (122) is in contact with water and the moisture content of the polymer electrolyte membrane (110) on the oxygen generation electrode (122) side is relatively high, there is no need to supply additional water. In addition, the catalyst layer of the oxygen generation electrode (122) includes a noble metal oxide such as iridium oxide, an oxide of an iridium alloy, or a combination thereof, and since such noble metal oxides have hydrophilic properties, they help to further increase the moisture content of the oxygen generation electrode (122), so there is no need to supply additional water to the oxygen generation electrode (122).

[0087] For example, the first and second sub-gaskets (131, 132) may be an overlap type in which the edges of the hydrogen generation electrode (121) and the oxygen generation electrode (122) are covered by the first and second sub-gaskets (131, 132) as illustrated in FIG. 1, but the present invention is not limited thereto, and the first and second sub-gaskets (131, 132) may also be an edge-fit type in which the entire hydrogen generation electrode (121) and the oxygen generation electrode (122) are exposed through the first and second windows, respectively.

[0088] The first and second sub-gaskets (131, 132) may be formed in the form of a film made of a non-porous material that has good heat resistance and chemical resistance in a temperature range from room temperature to 120 °C, can withstand a pressure of 100 torque or more, and has relatively low gas permeability. For example, each of the first and second sub-gaskets (131, 132) may include polyimide (PI), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), fluorinated ethylene propylene (FEP), polyethylene naphthalate (PEN), or a combination thereof.

[0089] Fig. 3 is a cross-sectional view of a membrane-electrode assembly according to one embodiment. Fig. 4 is a plan view of the membrane-electrode assembly according to Fig. 3.

[0090] Referring to FIGS. 3 and 4, the membrane-electrode assembly is identical to the membrane-electrode assembly illustrated in FIGS. 1 and 2, except that the membrane-electrode assembly further includes a first gas diffusion layer (141) positioned over the hydrogen generation electrode (121) and a second gas diffusion layer (142) positioned over the oxygen generation electrode (122).

[0091] The first and second gas diffusion layers (141, 142) provide a gas diffusion path from the flow channel of the first and second separators (161, 162) described below to the hydrogen generation electrode (121) and the oxygen generation electrode (122) so that the supply fluid can be easily and uniformly supplied to the hydrogen generation electrode (121) and the oxygen generation electrode (122), so that the product can be removed out of the hydrogen generation electrode (121) and the oxygen generation electrode (122), and can prevent a rapid decrease in the water content of the polymer electrolyte membrane (110) by storing a certain amount of water, and can provide sufficient mechanical strength to the membrane-electrode assembly.

[0092] For example, the first gas diffusion layer (141) located on the side of the hydrogen generation electrode (121) may be a gas diffusion layer (GDL) made of carbon material, and the second gas diffusion layer (142) located on the side of the oxygen generation electrode (122) may be a porous transport layer (multi-porous transport layer; MPL or porous transport layer; PTL) made of metal material.

[0093] For example, the first gas diffusion layer (141) may include an electrically conductive porous member such as carbon paper, carbon cloth, carbon felt, metal paper, metal cloth, metal felt, etc.

[0094] In addition, the second gas diffusion layer (142) may include a plurality of fibers. The plurality of fibers may be integrated in the form of a non-woven fabric including a plurality of pores. The plurality of fibers may include a metal oxide or a metal. For example, the plurality of fibers may be a metal oxide including titanium dioxide (TiO2), tungsten oxide (WO3), silicon oxide (SnO2), ruthenium oxide (RuO2), ATO, ITO, manganese dioxide (MnO2), or molybdenum trioxide (MoO3), or a metal including titanium (Ti), gold (Au), or stainless steel (SUS). In this way, when the second gas diffusion layer (142) includes a plurality of fibers including a metal oxide such as titanium (TiO2), the metal oxide has hydrophilic properties, which can help to further increase the moisture content of the oxygen generation electrode (122), and thus, there is no need to additionally supply water to the oxygen generation electrode (122).

[0095] The diameter and length of the plurality of fibers may be within a predetermined range. The diameter and length of the plurality of fibers may be measured by photographing the second gas diffusion layer (142) using a scanning electron microscope (SEM). For example, the diameter of the fibers may be 5 μm to 100 μm, and the length of the fibers may be 10 μm to 2 mm.

[0096] The second gas diffusion layer (142) can be appropriately adjusted in thickness and porosity to ensure an appropriate diffusion effect of the reactant. For example, the thickness of the second gas diffusion layer (142) can be within a predetermined range. The thickness of the second gas diffusion layer (142) can be measured according to a method for measuring the diameter and length of a plurality of fibers. The thickness of the second gas diffusion layer (142) can be 30 μm to 500 μm. In addition, the porosity of the second gas diffusion layer (142) can be within a predetermined range. The porosity of the second gas diffusion layer (142) can be measured according to a mercury intrusion porosimetry method. The porosity of the second gas diffusion layer (142) can be 30% to 80%.

[0097] Fig. 5 is a cross-sectional view of a membrane-electrode assembly according to one embodiment. Fig. 6 is a plan view of the membrane-electrode assembly according to Fig. 5.

[0098] Referring to FIGS. 5 and 6, the membrane-electrode assembly is identical to the membrane-electrode assembly illustrated in FIGS. 3 and 4, except that it further includes a first gasket (151) disposed over a first sub-gasket (131) and surrounding a first gas diffusion layer (141) and a second gasket (152) disposed over a second sub-gasket (132) and surrounding a second gas diffusion layer (142).

[0099] The first gasket (151) may be placed on the first surface of the inactive region (110a) of the polymer electrolyte membrane (110), and the second gasket (152) may be placed on the second surface of the inactive region (110a) of the polymer electrolyte membrane (110).

[0100] Each of the first and second gaskets (151, 152) has a third and a fourth window to accommodate the first and second gas diffusion layers (141, 142) and expose the first and second gas diffusion layers (141, 142). For example, the third window may be a hole positioned at the center of the first gasket (151) and penetrating the first gasket (151) in the thickness direction. In addition, the fourth window may be a hole positioned at the center of the second gasket (152) and penetrating the second gasket (152) in the thickness direction. That is, the third and fourth windows may be vacant holes.

[0101] In other words, when the side of the first gasket (151) facing the hydrogen generation electrode (121) is referred to as the first side, and the side opposite the first side is referred to as the second side, the first gas diffusion layer (141) penetrates the first side and the second side of the first gasket (151), and the first gas diffusion layer (141) can be exposed to the second side of the first gasket (151). In addition, when the side of the second gasket (152) facing the oxygen generation electrode (122) is referred to as the first side, and the side opposite the first side is referred to as the second side, the second gas diffusion layer (142) penetrates the first side and the second side of the second gasket (152), and the second gas diffusion layer (142) can be exposed to the second side of the second gasket (152). The first gasket (151) can surround the first gas diffusion layer (141), and the second gasket (152) can surround the second gas diffusion layer (142).

[0102] The first gasket (151) has a third water supply path (P21) corresponding to the inactive region (110a) of the polymer electrolyte membrane (110). In other words, the third water supply path (P21) of the first gasket (151) can overlap with the inactive region (110a) of the polymer electrolyte membrane (110) in the thickness direction.

[0103] For example, on the plane of the first gasket (151), the third water supply path (P21) may be located in an area corresponding to the inactive area (110a) of the polymer electrolyte membrane (110). In addition, the third water supply path (P21) may be located in an area corresponding to the first water supply path (P11) of the first sub-gasket (131). The third water supply path (P21) may be located at a certain distance from the third window and may surround the third window. For example, the third water supply path (P21) may extend to surround four sides of the third window. However, one end and the other end of the third water supply path (P21) may not meet but may be spaced apart from each other. Accordingly, the first gasket (151) may have a single configuration in which the third window portion and the third water supply path (P21) portion are not separated but connected.

[0104] The third water supply path (P21) may be a hole penetrating the first gasket (151) in the thickness direction. That is, the third water supply path (P21) may be a vacant hole. Accordingly, the inactive region (110a) of the polymer electrolyte membrane (110) may be exposed to the second surface of the first gasket (151) through the third water supply path (P21) of the first gasket (151).

[0105] When water reaches the inactive region (110a) of the polymer electrolyte membrane (110) through the third water supply path (P21) of the first gasket (151), a difference in water concentration occurs between the inactive region (110a) and the active region of the polymer electrolyte membrane (110). As a result, water flows from the inactive region (110a) to the active region according to Fick's law of diffusion, which states that water flows from a region of high water concentration to a region of low water concentration. By directly supplying water to the polymer electrolyte membrane (110), the moisture content of the polymer electrolyte membrane (110) is increased, thereby improving the ionic conductivity of the polymer electrolyte membrane (110), and additionally, the membrane-electrode assembly is cooled to reduce the required energy, thereby maximizing the performance of the water electrolysis cell.

[0106] Meanwhile, the second gasket (152) does not have a water supply path corresponding to the inactive region (110a) of the polymer electrolyte membrane (110).

[0107] For example, on the plane of the second gasket (152), the area corresponding to the inactive area (110a) of the polymer electrolyte membrane (110) does not have a water supply path and is blocked by the second gasket (152). Therefore, the inactive area (110a) of the polymer electrolyte membrane (110) is not exposed to the second surface of the second gasket (152).

[0108] The first and second gaskets (151, 152) are for preventing leakage of fluid and may include, for example, ethylene propylene diene monomer (EPDM), neoprene, urethane, acrylonitrile butadiene rubber (NBR), or polytetrafluoroethylene (PTFE).

[0109] Fig. 7 is a cross-sectional view of a hydrocarbon cell according to one embodiment. Fig. 8 is a plan view of the separator illustrated in Fig. 7, showing the surface facing the membrane-electrode assembly.

[0110] Referring to FIGS. 7 and 8, the electrolysis cell includes a membrane-electrode assembly, a first separator (161) positioned on a first side of the membrane-electrode assembly, and a second separator (162) positioned on a second side of the membrane-electrode assembly.

[0111] As described above, the membrane-electrode assembly includes a polymer electrolyte membrane (110) having an active region and a passive region (110a) surrounding the active region, a hydrogen generation electrode (121) positioned on a first side of the active region of the polymer electrolyte membrane (110), an oxygen generation electrode (122) positioned on a second side of the active region of the polymer electrolyte membrane (110), a first gasket (151) positioned on the first side of the passive region (110a) of the polymer electrolyte membrane (110) and surrounding the hydrogen generation electrode (121), and a second sub-gasket (132) positioned on the second side of the passive region (110a) of the polymer electrolyte membrane (110) and surrounding the oxygen generation electrode (122). The first sub-gasket (131) may have a first water supply path (P11) exposing the passive region (110a) of the polymer electrolyte membrane (110).

[0112] Additionally, the membrane-electrode assembly may further include a first gas diffusion layer (141) positioned over the hydrogen generation electrode (121) and a second gas diffusion layer (142) positioned over the oxygen generation electrode (122), and may further include a first gasket (151) positioned over the first sub-gasket (131) and surrounding the first gas diffusion layer (141), and a second gasket (152) positioned over the second sub-gasket (132) and surrounding the second gas diffusion layer (142). The first gasket (151) may have a third water supply path (P21) corresponding to the inactive region (110a) of the polymer electrolyte membrane (110).

[0113] The first separator (161) has a first flow channel (161a) for supplying a first gas to the hydrogen generation electrode (121), and the second separator (162) has a second flow channel (162a) for supplying a second gas to the oxygen generation electrode (122). A gas inlet (GI) and a gas outlet (GO) may be positioned at one end and the other end of each of the first and second flow channels (161a, 162a), respectively.

[0114] The first separator (161) may have a water channel (161b) corresponding to the inactive region (110a) of the polymer electrolyte membrane (110). In other words, the water channel (161b) of the first separator (161) may overlap with the inactive region (110a) of the polymer electrolyte membrane (110) in the thickness direction.

[0115] For example, on the plane of the first separator (161), the water channel (161b) may be located in an area corresponding to the inactive area (110a) of the polymer electrolyte membrane (110). The water channel (161b) may be located at a predetermined distance from the first flow channel (161a) and may surround the first flow channel (161a). For example, the water channel (161b) may extend to surround four sides of the first flow channel (161a). However, one end and the other end of the water channel (161b) may not meet but may be spaced apart from each other. A water inlet (WI) and a water outlet (WO) may be located at one end and the other end of the water channel (161b), respectively. Accordingly, the first separator (161) can be configured compactly by including only a total of four minimized inlets and outlets: a gas inlet (GI) and a gas outlet (GO) of the first flow channel (161a), and a water inlet (WI) and a water outlet (WO) of the water channel (161b).

[0116] For example, the area ratio of the water channel (161b) to the total area of ​​the first separator (161) may be 10% to 80%, and the depth ratio of the first water channel (161b) to the total thickness of the first separator (161) may be 5% to 40%. When the area ratio of the water channel (161b) is less than 10% or the depth ratio of the first water channel (161b) is less than 5%, water may not be sufficiently supplied to the inactive region (110a) of the polymer electrolyte membrane (110) through the first and third water supply paths (P11, P21). If the area ratio of the water channel (161b) exceeds 80% or the depth ratio of the first water channel (161b) exceeds 40%, too much water may be supplied to the inactive region (110a) of the polymer electrolyte membrane (110), causing a flooding phenomenon, or the concentration difference of water may become small, preventing water from being supplied toward the active region according to Fick's law of diffusion.

[0117] Water flows into the water inlet (WI) of the first separator (161) and flows along the water channel (161b), and is supplied to the inactive region (110a) of the polymer electrolyte membrane (110) through the first water supply path (P11) of the first sub-gasket (131), and the remaining water is discharged through the water discharge port (WO) of the first separator (161). When water reaches the inactive region (110a) of the polymer electrolyte membrane (110) through the first water supply path (P11) of the first sub-gasket (131), a difference in water concentration occurs between the inactive region (110a) and the active region of the polymer electrolyte membrane (110). As a result, water flows from the inactive region (110a) to the active region according to Fick's law of diffusion, which states that water flows from a region of high water concentration to a region of low water concentration. By directly supplying water to the polymer electrolyte membrane (110), the ionic conductivity of the polymer electrolyte membrane (110) is improved by increasing the moisture content of the polymer electrolyte membrane (110), and additionally, the performance of the water electrolysis cell can be maximized by cooling the membrane-electrode assembly to reduce the required energy.

[0118] [Manufacturing Example: Manufacturing of a Membrane-Electrode Assembly]

[0119] Normal propyl alcohol (nPA) as a solvent, commercial IrO as a catalyst for oxygen evolution reaction x Black powder (Merck Sigma-Aldrich, Iridium(IV) oxide 206237) and Nafion as an ion conductor in a weight ratio of 1:0.2 (IrO x :Nafion) was mixed. The solvent was additionally mixed so that the solid content was 5 wt%. The loading amount was 0.5 mg / cm 2 An oxygen generating electrode having a thickness of approximately 10 μm was formed by spray coating on a coating substrate film (PI Advanced Materials, PI film) having a width of 2 cm, a length of 2 cm, and a thickness of approximately 200 μm.

[0120] Pt / C carbon with 50 wt% Pt loading and Nafion as an ion conductor were mixed in a weight ratio of 1:1.2 (Pt / C:Nafion), and a solvent was additionally mixed so that the solid content was 5 wt%. The loading amount was 0.5 mg / cm 2 A hydrogen generation electrode having a thickness of about 30 μm was formed by spray coating on a coating substrate film (PI Advanced Materials, PI film) having a width of 2 cm, a length of 2 cm, and a thickness of about 200 μm.

[0121] As a polymer electrolyte membrane, an oxygen generation electrode and a hydrogen generation electrode were sequentially placed on both sides of a commercial NR212 from Chemours with a thickness of about 50.8 μm, and the electrode was placed at 5 N for 150 o After hot-pressing at a temperature of C for 5 minutes, the coating substrate film was removed to manufacture a polymer electrolyte membrane-electrode assembly.

[0122] On both sides of the manufactured polymer electrolyte membrane-electrode assembly, as shown in FIGS. 7 and 8, a first sub-gasket (131) having a first water supply path (P11) and a second sub-gasket (132) not having a water supply path are laminated, and then a first gas diffusion layer (141) made of carbon material and a second gas diffusion layer (142) made of metal material, a first gasket (151) having a third water supply path (P21) and a second sub-gasket (132) not having a water supply path, a first separator (161) having a water channel (161b) and a second separator (162) not having a water channel are sequentially laminated to manufacture a water electrolysis cell according to an embodiment.

[0123] In addition, a water electrolysis cell according to a comparative example was manufactured in the same manner as in the example, except that a first sub-gasket (131) without a first water supply path (P11), a first gasket (151) without a third water supply path (P21), and a first separator (161) without a water channel (161b) were used.

[0124] [Experimental Example: Measurement of the Moisture Content of a Polymer Electrolyte Membrane]

[0125] The water content of the polymer electrolyte membrane was measured for the electrolysis cell according to the examples and comparative examples, and the results are shown in Table 1.

[0126] The functional content was measured by the lambda measurement method using an X-ray microtomography device.

[0127] (1) Experimental device configuration

[0128] 1) X-ray microtomography device: Synchrotron-based X-ray microtomography system from Advanced Light Source (ALS).

[0129] - X-ray source: Using a synchrotron X-ray source, it provides a very high photon flux and high spatial resolution compared to general laboratory equipment.

[0130] - Spatial resolution: It has a high resolution of approximately 1 μm, enabling precise visualization of water distribution and density changes for each pixel.

[0131] - Temporal resolution: Each imaging session is set to a temporal resolution of approximately 10 minutes, enabling the chronological tracking of dynamic changes in material transport.

[0132] 2) Sample fixture and holder: A sample holder specially designed to fix the polymer electrolyte membrane sample is used.

[0133] - Sample holding device structure: Designed to accurately maintain the position of the polymer electrolyte membrane sample and create various water boundaries.

[0134] Gas Flow Control: Dry nitrogen (N₂) is supplied to one side of the polymer electrolyte membrane sample, and water-containing vapor or liquid is supplied to the other side to establish various boundary conditions. This creates an environment where one side of the polymer electrolyte membrane is dried, while the other side is exposed to vapor or liquid.

[0135] - Temperature and humidity control function: The temperature and humidity inside the sample holder can be precisely controlled, allowing a constant environment to be maintained during the experiment.

[0136] - Water supply function to gasket euro: Designed to supply water and control the flow rate to the gasket euro, and is used with a precision pump.

[0137] (2) Experimental procedure

[0138] 1) Initial sample preparation: Experiments were conducted by preparing dry polymer electrolyte membrane samples, vapor-saturated polymer electrolyte membrane samples, and liquid-saturated polymer electrolyte membrane samples, respectively. The initial sample states were set as follows.

[0139] - Dry state: has a moisture content of λ = 2.

[0140] - Steam saturated state: has a moisture content of λ = 14.

[0141] - Liquid saturated state: has a moisture content of λ = 22.

[0142] 2) Experimental details: Various boundary conditions were set to clearly observe the water distribution and moisture movement in the polymer electrolyte membrane.

[0143] - 5 cc / min of water is supplied to the gasket side of the hydrogen generation electrode, and 10 cc / min of water is supplied to the gasket side of the oxygen generation electrode in the same manner as actual water electrolysis.

[0144] - Profile changes over time: Using X-ray microtomography, the water distribution was photographed at each time point. Initially, the λ value starts at 2, and it is observed that the λ value gradually increases over time and stabilizes at a certain λ value.

[0145] Example Comparison Example Lambda (λ) HER λOER λ Average λ HER λOER λ Average λ Value 20.3 22.0 21.2 5.5 22.1 13.8 Condition 5 cc / min 10 cc / min--10 cc / min-

[0146] Referring to Table 1, in the case of the electrolysis cell according to the embodiment, water is not supplied to the hydrogen generation electrode side through the first flow channel, but only through the water channel, and water is supplied to the oxygen generation electrode side through the second flow channel, so that water flows from the inactive region (110a) to the active region according to Fick's diffusion law, and water is directly supplied to the polymer electrolyte membrane (110), thereby increasing the moisture content of the polymer electrolyte membrane (110). On the other hand, in the case of the electrolysis cell according to the comparative example, water is not supplied at all to the hydrogen generation electrode side, and water is supplied to the oxygen generation electrode side through the second flow channel. Accordingly, it can be seen that the electrolysis cell according to the comparative example has a polymer electrolyte membrane with a lower moisture content than the electrolysis cell according to the embodiment.

[0147] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and various modifications can be made within the scope of the claims, the description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present disclosure.

[0148] [Explanation of symbols]

[0149] 110: Polymer electrolyte membrane

[0150] 110a: Inactive area

[0151] 121: Hydrogen generation electrode

[0152] 122: Oxygen generating electrode

[0153] 131: First sub-gasket

[0154] 132: Second sub-gasket

[0155] P11: First water supply route

[0156] 141: First gas diffusion layer

[0157] 142: Second gas diffusion layer

[0158] 151: First gasket

[0159] 152: Second gasket

[0160] P21: Third water supply route

[0161] 161: 1st separator

[0162] 161a: First flow channel

[0163] 162: Second Separator

[0164] 162a: Second flow channel

[0165] 161b: Water channel

[0166] The present disclosure relates to a membrane-electrode assembly for a water electrolysis cell and a water electrolysis cell including the same, wherein water is directly supplied to a polymer electrolyte membrane to increase the water content of the polymer electrolyte membrane, thereby improving the ionic conductivity of the polymer electrolyte membrane, and additionally cooling the membrane-electrode assembly to reduce the required energy, thereby maximizing the performance of the water electrolysis cell.

Claims

1. A polymer electrolyte membrane having an active area and an inactive area surrounding the active area; A hydrogen generation electrode positioned on the first surface of the active region of the polymer electrolyte membrane; An oxygen generation electrode positioned on the second surface of the active region of the polymer electrolyte membrane; A first sub-gasket disposed on the first surface of the inactive region of the polymer electrolyte membrane and surrounding the first electrode; and A second sub-gasket is disposed on the second surface of the inactive region of the polymer electrolyte membrane and surrounds the second electrode; The first sub-gasket has a first window accommodating the hydrogen generation electrode, and a first water supply path surrounding the first window and exposing the inactive region of the polymer electrolyte membrane. Membrane-electrode assembly for a hydroelectric cell.

2. In paragraph 1, The first window penetrates the first sub-gasket to expose the hydrogen generation electrode, The first water supply path penetrates the first sub-gasket to expose the inactive region of the polymer electrolyte membrane. Membrane-electrode assembly for a hydroelectric cell.

3. In paragraph 1, The above first window and the above first water supply path are vacant holes, Membrane-electrode assembly for a hydroelectric cell.

4. In paragraph 1, The above first water supply path extends to surround the four sides of the above first window, One end and the other end of the above first water supply path do not meet and are spaced apart from each other. Membrane-electrode assembly for a hydroelectric cell.

5. In paragraph 1, The second sub-gasket has a second window that accommodates the oxygen generating electrode, Not having a water supply path exposing the inactive region of the polymer electrolyte membrane, Membrane-electrode assembly for a hydroelectric cell.

6. In paragraph 5, The above oxygen generation electrode comprises a noble metal oxide catalyst including iridium oxide, an oxide of an iridium alloy, or a combination thereof. Membrane-electrode assembly for a hydroelectric cell.

7. In paragraph 1, The membrane-electrode assembly for the above-mentioned water electrolysis cell is, a first gas diffusion layer positioned on the hydrogen generation electrode; and further comprising a second gas diffusion layer positioned above the oxygen generating electrode; Membrane-electrode assembly for a hydroelectric cell.

8. In paragraph 7, The above first gas diffusion layer, An electrically conductive porous member comprising carbon paper, carbon cloth, carbon felt, metal paper, metal cloth, metal felt, or a combination thereof. Membrane-electrode assembly for a hydroelectric cell.

9. In paragraph 7, The second gas diffusion layer is, Contains a plurality of fibers integrated into a form containing a plurality of pores, A plurality of fibers comprising a metal oxide or a metal, Membrane-electrode assembly for a hydroelectric cell.

10. In paragraph 7, The membrane-electrode assembly for the above-mentioned water electrolysis cell is, A first gasket disposed on the first sub-gasket and surrounding the first gas diffusion layer; and Further comprising a second gasket disposed on the second sub-gasket and surrounding the second gas diffusion layer; The first gasket has a third window accommodating the first gas diffusion layer, and a third water supply path surrounding the third window and exposing the first water supply path of the first gas diffusion layer. Membrane-electrode assembly for a hydroelectric cell.

11. Membrane-electrode assembly according to paragraph 1; a first separator positioned on the first side of the membrane-electrode assembly; and A second separator positioned on the second surface of the membrane-electrode assembly; The above first separator comprises a flow channel located in an area corresponding to the hydrogen generation electrode, and Having a water channel surrounding the first flow channel and located in an area corresponding to the first water supply path, Susan Hae-sel.

12. In Article 11, The above water channel extends to surround the four sides of the above flow channel, One end of the above water channel and the other end do not meet and are spaced apart from each other. Susan Hae-sel.

13. In Article 11, One end of the above water channel has a water inlet, The other end of the above water channel has a water outlet, Susan Hae-sel.

14. In Article 11, The area ratio of the water channel to the total area of ​​the first separator is 10% to 80%, The ratio of the depth of the water channel to the total thickness of the first separator is 5% to 40%, Susan Hae-sel.

15. In paragraph 11, The above water cell is, a first gas diffusion layer positioned on the hydrogen generation electrode; and Further comprising a second gas diffusion layer positioned on the oxygen generating electrode; The second gas diffusion layer is, Contains a plurality of fibers integrated into a form containing a plurality of pores, A plurality of fibers comprising a metal oxide or a metal, Susan Hae-sel.

16. In paragraph 15, The above water cell is, A first gasket disposed on the first sub-gasket and surrounding the first gas diffusion layer; and Further comprising a second gasket disposed on the second sub-gasket and surrounding the second gas diffusion layer; The first gasket has a third window accommodating the first gas diffusion layer, and a third water supply path surrounding the third window and exposing the first water supply path of the first gas diffusion layer. Susan Hae-sel.

Images