Catalyst for oxygen evolution reaction in water electrolysis cell and production method therefor, and membrane-electrode assembly for water electrolysis cell and water electrolysis cell, each comprising catalyst

Abstract

Provided is a catalyst for an oxygen evolution reaction in a water electrolysis cell, the catalyst comprising: water electrolysis catalyst particles containing a noble metal oxide; and a conductive additive containing a fluorine-doped metal oxide, wherein in the entire fluorine-doped metal oxide, the content of fluorine is 1 at% to 10 at% relative to a total of 100 at% of the components as measured by X-ray photoelectron spectroscopy (XPS).

Description

Catalyst for oxygen generation reaction in electrolytic cell and method for producing same, and membrane-electrode assembly and electrolytic cell for electrolytic cell including same

[0001] The present invention relates to a catalyst for an oxygen generation reaction in a water electrolysis cell and a method for producing the same, and a membrane-electrode assembly and a water electrolysis cell including the same.

[0002] This research was supported by the Ministry of Trade, Industry and Energy (MOTIE) and the Korea Institute of Energy Technology Evaluation and Planning (KETEP). (Project ID: 20223030040220)

[0003] Recent energy demands and environmental concerns demand sustainable supply, environmental friendliness, and high efficiency, and among these, hydrogen is attracting attention as a raw material for renewable energy.

[0004] Hydrogen energy is categorized as gray, blue, and green hydrogen depending on its production method. Gray and blue hydrogen use fossil fuels, which generate carbon dioxide during production and pose the problem of not being able to completely eliminate it. Green hydrogen is produced through water electrolysis. Because it produces no carbon dioxide, it is attracting attention as the ultimate eco-friendly energy source. Water electrolysis technology is required to produce green hydrogen.

[0005] Water electrolysis is an electrochemical technology that generates hydrogen and oxygen by electrolyzing water and transporting ions across a membrane. Water electrolysis can be divided into two half-cell reactions: the hydrogen evolution reaction (HER), which occurs at the reduction electrode, and the oxygen evolution reaction (OER), which occurs at the oxidation electrode.

[0006] Regarding catalysts for water electrolysis, especially for oxygen evolution electrodes of polymer electrolyte membrane (PEM) water electrolysis, iridium black and iridium oxide powder have been used as oxygen evolution reaction catalysts for conventional PEM water electrolysis oxygen evolution electrodes, but improvements are required for their low dispersibility, low electrical conductivity, and instability.

[0007] The present invention provides a catalyst for oxygen evolution reaction in electrolysis cells that can exhibit high electrochemical durability and conductivity even in high-voltage and low-pH electrolysis operation environments by applying it to electrolysis cell electrodes while reducing the amount of precious metals used.

[0008] In one embodiment, a catalyst for an oxygen evolution reaction of a water electrolysis cell is provided, comprising: a water electrolysis catalyst particle containing a noble metal oxide; and a conductive additive containing a fluorine-doped metal oxide; wherein the fluorine content of the entire fluorine-doped metal oxide is 1 at% to 20 at% with respect to 100 at% of the total components measured by X-ray photoelectron spectroscopy.

[0009] In another embodiment, an oxygen generation electrode including a catalyst for an oxygen generation reaction of the above-described electrolysis cell is provided.

[0010] In another embodiment, a method for manufacturing an oxygen generation electrode is provided, comprising: (i) a step of manufacturing a metal oxide; (ii) a step of mixing the metal oxide and a fluorine precursor, and then performing a heat treatment to manufacture a fluorine-doped metal oxide; (iii) a step of mixing a noble metal oxide and an ionomer to manufacture a slurry; and (iv) a step of mixing the slurry and the fluorine-doped metal oxide, and then dispersing the mixture.

[0011] In another embodiment, a membrane-electrode assembly for a water electrolysis cell is provided, comprising: a polymer electrolyte membrane; an oxygen generation electrode positioned on one side of the polymer electrolyte membrane; and a hydrogen generation electrode positioned on the other side of the polymer electrolyte membrane.

[0012] In another embodiment, a water electrolysis cell comprising a membrane-electrode assembly for the water electrolysis cell is provided.

[0013] A catalyst for oxygen generation reaction of a water electrolysis cell manufactured according to an embodiment of the present invention can exhibit high electrochemical durability and conductivity even in a high-voltage and low-pH water electrolysis operating environment by applying it to a water electrolysis cell electrode while reducing the amount of precious metal used.

[0014] Figure 1 is a schematic diagram showing a membrane-electrode assembly (MEA) for a water electrolysis cell.

[0015] Figure 2 is a graph showing the initial electrolysis performance of the membrane-electrode assemblies manufactured in Example 5, Comparative Example 2, and Comparative Example 3.

[0016] Figure 3 is a graph showing the electrolysis performance after a degradation test of the membrane-electrode assembly manufactured in Example 5, Comparative Example 2, and Comparative Example 3.

[0017] Figure 4 is a graph showing the initial electrolysis performance and the change in electrolysis performance after a degradation test of the membrane-electrode assembly manufactured in Example 5, Comparative Example 2, and Comparative Example 3.

[0018] Below, specific implementation examples are described in detail to facilitate their implementation by those skilled in the art. However, the present invention may be implemented in various different forms and is not limited to the implementation examples described herein.

[0019] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0020] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0021] It should be understood that the terms "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0022] To clearly illustrate various layers and regions in the drawings, their thicknesses are enlarged, and similar parts are designated by the same drawing reference numerals throughout the specification. When an element such as a layer, film, region, or plate is said to be "over" or "on" another element, this includes not only the case where it is "directly over" the other element, but also the case where there are other elements in between. Conversely, when an element is said to be "directly over" another element, it means that there are no other elements in between.

[0023] “Layer” includes not only shapes formed on the entire surface when observed in a plan view, but also shapes formed on some surfaces.

[0024] The average particle size can be measured by methods well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with transmission electron microscope images or scanning electron microscope images. Alternatively, the average particle size can be obtained by measuring using dynamic light scattering, performing data analysis, counting the number of particles for each particle size range, and calculating from the counted number. Unless otherwise defined, the average particle size is the diameter (D) of the particles in the particle size distribution that have a cumulative volume of 50% by volume. 50 ) can mean. In addition, unless otherwise defined, the average particle size is obtained by measuring the size (diameter or length of major axis) of about 20 particles randomly in a scanning electron microscope image to obtain a particle size distribution, and the diameter (D) of the particle having a cumulative volume of 50% by volume in the particle size distribution 50 ) may be taken as the average particle diameter.

[0025] “Or” is not interpreted as exclusive, for example, “A or B” is interpreted as including A, B, A+B, etc.

[0026] “Metal” is interpreted as a concept that includes common metals, transition metals, and metalloids (semi-metals).

[0027] Catalyst for oxygen evolution reaction

[0028] In this specification, a catalyst for oxygen evolution reaction means a catalyst applied to an electrode (hereinafter referred to as an oxygen evolution electrode) where an oxygen evolution reaction (OER) takes place. In other words, it means a catalyst included in an oxygen evolution electrode described below.

[0029] A catalyst for an oxygen evolution reaction of a water electrolysis cell according to one embodiment comprises: water electrolysis catalyst particles containing a noble metal oxide; and a conductive additive containing a fluorine-doped metal oxide; wherein the fluorine content of the entire fluorine-doped metal oxide is 1 at% to 20 at% based on 100 at% of the total components measured by X-ray photoelectron spectroscopy (XPS).

[0030] The above oxygen generation reaction catalyst can have improved performance and durability depending on the type, shape, and content of the electrolysis catalyst particles and conductive additives.

[0031] In polymer electrolyte membrane electrolysis cells, noble metal oxides are used as catalysts for oxygen evolution reactions. However, due to the low electrical conductivity of noble metal oxides, there is a problem that a high content of noble metals is required. In order to reduce the content of noble metals, a conductive additive that can compensate for the low electrical conductivity is required. Accordingly, in one embodiment, a fluorine-doped metal oxide is used as a conductive additive. However, since the reactivity of fluorine is too high, it is difficult to control the doping amount and uniformly dope fluorine. In order to solve this problem, a water electrolysis electrode having high electrical conductivity and electrochemical corrosion resistance is proposed through a uniformly fluorine-doped metal oxide.

[0032] Water electrolysis catalyst particles

[0033] According to one embodiment, the electrolysis catalyst particle contains a precious metal oxide, and the precious metal may be a non-platinum based precious metal. For example, the non-platinum based precious metal may include palladium (Pd), ruthenium (Ru), iridium (Ir), an alloy thereof, or a combination thereof. The precious metal oxide according to one embodiment is IrO x (x is an integer from 1 to 3), RuO x (x is an integer from 1 to 3), PdOx (x is an integer from 1 to 3), IrMO x (M includes Ru, Sn, Ti, Te, Nb, or a combination thereof, and x is an integer from 1 to 3), or a combination thereof, and more specifically, IrO x (x is an integer from 1 to 3). When the electrolysis catalyst particle includes the noble metal oxide, it has the advantage of exhibiting high catalytic activity.

[0034] The above-mentioned electrolysis catalyst particles may be in a form supported on a support or not supported on a support, and more specifically, may be in a form supported on a support. The support may contain a metal oxide, and the metal oxide may include tungsten oxide, titanium oxide, nickel oxide, ruthenium oxide, tantalum oxide, tin oxide, cobalt oxide, or a combination thereof. When the catalyst for the oxygen evolution reaction of the electrolysis cell includes the support, there is an advantage in that it can exhibit high catalytic activity even when the content of the precious metal is low by compensating for the low electrical conductivity of the electrolysis catalyst particles containing the precious metal oxide. In addition, the support may have various shapes, and may have, for example, a shape such as a sphere, a wire, a rod, a sheet, or a capsule.

[0035] The average particle diameter (D) of the above electrolysis catalyst particles 50) may be 1 nm to 15 nm, for example, 2 nm to 12 nm, or 4 nm to 10 nm. In addition, when the electrolysis catalyst particles are supported on a carrier, the average particle diameter of the electrolysis catalyst particles may be 1 nm to 15 nm, for example, 2 nm to 12 nm, or 4 nm to 10 nm. The average particle diameter is obtained by randomly measuring the size (diameter or length of major axis) of about 20 particles in a scanning electron microscope image of the electrolysis catalyst particles to obtain a particle size distribution, and the diameter (D) of the particles having a cumulative volume of 50% by volume in the particle size distribution 50 ) may be taken as the average particle diameter. Here, the average particle diameter of the electrolysis catalyst particles may be smaller than the average particle diameter of the conductive additive described later. The oxygen generation reaction catalyst according to one embodiment is a mixed form of electrolysis catalyst particles and the conductive additive described later, and thus a conductive network can be formed to reduce the sheet resistance of the electrode and improve the performance of the electrolysis cell.

[0036] In one embodiment, the electrolysis catalyst particles may be included in an amount of 60 wt% to 95 wt%, for example, 65 wt% to 85 wt%, or 70 wt% to 95 wt%, based on 100 wt% of the total of the electrolysis catalyst particles and the conductive additive. When the content ratio of the electrolysis catalyst particles and the conductive additive is as described above, the oxygen evolution reaction catalyst including the same can form a conductive network to reduce the sheet resistance of the electrode and improve the performance of the electrolysis cell.

[0037] conductive additives

[0038] In one embodiment, the conductive additive contains a fluorine-doped metal oxide, and the metal may include, for example, tungsten (W), titanium (Ti), nickel (Ni), ruthenium (Ru), tantalum (Ta), tin (Sn), cobalt (Co), or a combination thereof. Accordingly, the metal oxide may include tungsten oxide, titanium oxide, nickel oxide, ruthenium oxide, tantalum oxide, tin oxide, cobalt oxide, or a combination thereof, and preferably includes tin oxide. When the oxygen evolution reaction catalyst includes the conductive additive, it has the advantage of complementing the low electrical conductivity of the water electrolysis catalyst particles containing the noble metal oxide, thereby exhibiting high catalytic activity even when the noble metal content is low. In addition, since fluorine is doped into the metal oxide included in the conductive additive, the bonding strength with the metal oxide is improved, thereby preventing the doped fluorine or the metal of the metal oxide from being eluted in the water electrolysis operating environment, thereby deteriorating the membrane electrode performance.

[0039] The conductive additive may have various shapes, for example, a shape such as a sphere, a wire, a rod, a sheet, or a capsule, and more specifically, a shape such as a sphere or a wire. When the conductive additive has a sphere shape, the average particle diameter (D) of the conductive additive 50 ) may be 0.05 ㎛ to 0.5 ㎛, for example, 0.05 ㎛ to 0.3 ㎛, 0.05 ㎛ to 0.3 ㎛, or 0.05 ㎛ to 0.1 ㎛. The average particle diameter is obtained by measuring the size (diameter or length of major axis) of about 20 particles randomly in a scanning electron microscope image for a conductive additive to obtain a particle size distribution, and the diameter (D) of particles having a cumulative volume of 50% by volume in the particle size distribution 50) may be taken as the average particle diameter. Here, the average particle diameter of the conductive additive may be smaller than the average particle diameter of the electrolysis catalyst particles described above. In addition, when the conductive additive has a wire shape, the length of the conductive additive may be 1 ㎛ to 200 ㎛, for example, 3 ㎛ to 180 ㎛, 5 ㎛ to 165 ㎛, or 10 ㎛ to 150 ㎛, and the diameter of the conductive additive may be 0.1 ㎛ to 1.0 ㎛, for example, 0.2 ㎛ to 1.0 ㎛, 0.2 ㎛ to 0.9 ㎛, or 0.2 ㎛ to 0.8 ㎛. The oxygen generation reaction catalyst according to one embodiment is a mixed form of the conductive additive and the electrolysis catalyst particles described above, and thus, a conductive network may be formed to reduce the sheet resistance of the electrode and improve the performance of the electrolysis cell.

[0040] In one embodiment, the conductive additive may be included in an amount of 0.1 to 15 wt%, for example, 0.2 to 15 wt%, 0.4 to 12 wt%, or 0.5 to 10 wt%, based on 100 wt% of the total of the electrolysis catalyst particles and the conductive additive. When the content of the conductive additive is as described above, the oxygen evolution reaction catalyst including the same may form a conductive network to reduce the sheet resistance of the electrode and improve the performance of the electrolysis cell.

[0041] In one embodiment, the fluorine content of the entire fluorine-doped metal oxide relative to the total of 100 at% of components measured by X-ray photoelectron spectroscopy (XPS) is 1 at% to 20 at%, for example, 1 at% to 15 at%, 1 at% to 12 at%, 3 at% to 12 at%, 5 at% to 12 at%, 7 at% to 12 at%, 9 at% to 12 at%, or 10 at% to 12 at%. When the fluorine content of the entire fluorine-doped metal oxide satisfies the above range, uniform fluorine doping becomes possible, thereby reducing the sheet resistance of the electrode and improving the performance of the electrolysis cell.

[0042] oxygen generation electrode

[0043] An oxygen evolution electrode refers to an electrode where an oxygen evolution reaction (OER) occurs, and the oxygen evolution electrode may include a catalyst and an ion conductor for the oxygen evolution reaction of the water electrolysis cell described above. Since the catalyst for the oxygen evolution reaction of the water electrolysis cell has been described above, a detailed description thereof will be omitted.

[0044] The above oxygen generation electrode may contain 60 wt% to 95 wt% of the oxygen generation reaction catalyst of the water electrolysis cell with respect to 100 wt% of the total oxygen generation electrode, for example, 65 wt% to 85 wt%, or 70 wt% to 95 wt%.

[0045] The above oxygen generation electrode may further include an ion conductor to improve the adhesion of the catalyst and to transfer hydrogen ions, and the ion conductor may include a cation exchanger to secure ion conductivity. At this time, the oxygen generation electrode may include 1 wt% to 25 wt% of the ion conductor with respect to 100 wt% of the total oxygen generation electrode, for example, 2 wt% to 20 wt%, or 3 wt% to 18 wt%.

[0046] The above cation exchanger may be a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, a phosphonic acid group, an imide group, a sulfonimide group, a sulfonamide group, or a sulfonic acid fluoride.

[0047] The above ion conductor may be a fluorine-based ion conductor, a hydrocarbon-based ion conductor, or a mixture thereof. The above fluorine-based ion conductor may be a fluorine-based polymer having the cation exchange group in the side chain and containing fluorine in the main chain, such as poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), etc. The hydrocarbon-based ion conductor is a hydrocarbon-based polymer having the cation exchange group in the side chain [e.g., sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, sulfonated polyether sulfone, Sulfonated polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile,It can be sulfonated polyarylene ether, sulfonated polyarylene ether nitrile, sulfonated polyarylene ether ether nitrile, sulfonated polyarylene ether sulfone ketone, etc.

[0048] The ion conductor according to one embodiment may have hydrogen ion conductivity. The ion conductor having the hydrogen ion conductivity may also have H substituted with Na, K, Li, Cs or tetrabutylammonium in the cation exchanger at the end of the side chain. When H is substituted with Na in the ion exchanger at the end of the side chain, NaOH is used during the preparation of the catalyst composition, and when H is substituted with tetrabutylammonium, tetrabutylammonium hydroxide is used. K, Li or Cs may also be substituted using an appropriate compound. Since this substitution method is widely known in the art, a detailed description thereof will be omitted.

[0049] The above ion conductor can be used as a single substance or in the form of a mixture, and can also be optionally used together with a non-conductive compound for the purpose of further improving adhesion to a polymer electrolyte membrane. The content of the non-conductive compound can be appropriately adjusted depending on the intended use. As the non-conductive compound, at least one selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene / tetrafluoroethylene (ETFE), ethylene chlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), dodecylbenzenesulfonic acid, and sorbitol can be used.

[0050] Method for manufacturing an oxygen generation electrode

[0051] A method for manufacturing an oxygen generation electrode according to one embodiment includes: (i) a step of manufacturing a metal oxide; (ii) a step of mixing the metal oxide and a fluorine precursor, and then performing a heat treatment to manufacture a fluorine-doped metal oxide; (iii) a step of mixing a noble metal oxide and an ionomer to manufacture a slurry; and (iv) a step of mixing the slurry and the fluorine-doped metal oxide, and then dispersing the mixture.

[0052] In one embodiment, the step of manufacturing the metal oxide of (i) above may be performed according to a manufacturing method such as a hydrothermal synthesis method, an electrospinning synthesis method, an evaporation-induced self-assembly (EISA) method, etc. More specifically, a metal oxide precursor may be added to a predetermined solvent, mixed, and a basic compound may be further added to the mixed solution, and then the metal oxide may be manufactured under a predetermined temperature.

[0053] The above metal oxide precursor refers to a material in a previous stage of a metal oxide, which is a final product included in an oxygen evolution reaction catalyst of a water electrolysis cell. The type of the metal oxide may be tungsten oxide, titanium oxide, nickel oxide, ruthenium oxide, tantalum oxide, tin oxide, cobalt oxide, or a combination thereof, and preferably tin oxide (SnO2). Accordingly, the type of the metal oxide precursor is not limited as long as it can produce SnO2, which is a final product. For example, the metal oxide precursor may be tin ethoxide, tin butoxide, tin isopropoxide, SnCl4, SnCl2·2H2O, Sn(OH)4, or Sn(SO4)2, and more specifically, SnCl4 may be used.

[0054] The solvent is not limited in type as long as it can dissolve the metal oxide precursor. For example, the solvent may include water, alcohol, or a combination thereof, and the alcohol may be methanol, ethanol, butanol, or isopropanol.

[0055] The above basic compound may be added to appropriately adjust the pH. The above basic compound includes organic bases, ammonia, ammonium hydroxide, sodium hydroxide, potassium hydroxide, etc., and examples of the organic base include primary amines such as methylamine, ethylamine, isopropylamine, and monoisopropylamine; secondary amines such as diethylamine, diisopropylamine, and dibutylamine; tertiary amines such as trimethylamine, triethylamine, triisopropylamine, and tributylamine; Examples of the basic compound include alkanolamines such as tetramethylammonium hydroxide, choline, monoethanolamine, diethanolamine, 2-aminoethanol, 2-(ethylamino)ethanol, 2-(methylamino)ethanol, N-methyl diethanolamine, dimethylaminoethanol, diethylaminoethanol, nitrilotriethanol, 2-(2-amino ethoxy)ethanol, 1-amino-2-propanol, triethanolamine, monopropanolamine, and zibthanoramine. In order to control the pH, the content of the basic compound can be appropriately controlled. For example, the basic compound can be added in an amount of 20 ml to 200 ml, 40 ml to 180 ml, 60 ml to 160 ml, 80 ml to 140 ml, or 100 ml to 120 ml per 100 ml of the metal oxide precursor.

[0056] A reaction can be carried out at a predetermined temperature for a predetermined time in a mixed solution in which a basic compound is mixed with the above metal oxide precursor solution. For example, the temperature at which the reaction is carried out can be 40°C to 120°C, 45°C to 115°C, 50°C to 110°C, 55°C to 105°C, or 60°C to 100°C, and the time at which the reaction is carried out can be 48 hours to 96 hours, 54 hours to 90 hours, 60 hours to 84 hours, or 66 hours to 78 hours.

[0057] After the above reaction, a first heat treatment process can be performed. The first heat treatment process can be performed in an air atmosphere, and the first heat treatment temperature can be 200°C to 600°C, 225°C to 575°C, 250°C to 550°C, 275°C to 525°C, or 300°C to 500°C, and the time for which the first heat treatment process is performed can be 1 hour to 5 hours, 1.5 hours to 4.5 hours, or 2 hours to 4 hours.

[0058] The conductive additive containing the metal oxide can be adjusted to various sizes and shapes depending on pH, temperature, time, etc., and the conductive additive can have the shape of a sphere or wire. When the conductive additive has the shape of a sphere, the average particle diameter (D) of the conductive additive 50 ) may be 0.05 ㎛ to 0.5 ㎛, for example, 0.05 ㎛ to 0.3 ㎛, 0.05 ㎛ to 0.3 ㎛, or 0.05 ㎛ to 0.1 ㎛, and when the conductive additive has a wire shape, the conductive additive may be 1 ㎛ to 200 ㎛, for example, 3 ㎛ to 180 ㎛, 5 ㎛ to 165 ㎛, or 10 ㎛ to 150 ㎛, and the diameter of the conductive additive may be 0.1 ㎛ to 1.0 ㎛, for example, 0.2 ㎛ to 1.0 ㎛, 0.2 ㎛ to 0.9 ㎛, or 0.2 ㎛ to 0.8 ㎛. Accordingly, a conductive network can be formed to reduce the sheet resistance of the electrode and improve the performance of the electrolysis cell.

[0059] In one embodiment, in the step (ii) of preparing the fluorine-doped metal oxide, the type of the fluorine precursor may include NH4F, NH4HF2, or a combination thereof, and preferably NH4F. At this time, the molar ratio of the metal oxide and the fluorine precursor may be included as 1:0.1 to 1:20, for example, 1:0.5 to 1:20, 1:1 to 1:20, 1:3 to 1:20, 1:8 to 1:20, 1:13 to 1:20, or 1:18 to 1:20. When the molar ratio of the metal oxide and the fluorine precursor is included in the above range, the amount of fluorine to be doped can be easily controlled, making it possible to uniformly dope with fluorine, thereby reducing the sheet resistance of the electrode and improving the performance of the electrolysis cell.

[0060] After the mixing process of the metal oxide and the fluorine precursor is performed, a second heat treatment process may be performed. The second heat treatment process may be performed in an inert gas atmosphere, the heat treatment temperature may be 80°C to 450°C, 100°C to 430°C, or 120°C to 400°C, and the time for which the second heat treatment process is performed may be 4 hours to 8 hours, 4.5 hours to 7.5 hours, or 5 hours to 7 hours.

[0061] The above fluorine precursor may be in a solid state, and the solid fluorine precursor may be doped into the metal oxide through a second heat treatment. Conventional solution-based synthesis methods have the problem of difficulty in controlling the amount of fluorine doping. However, when a solid fluorine precursor is used, the amount of fluorine doping can be easily controlled, and agglomeration can be suppressed during the process of doping fluorine into the metal oxide, thereby synthesizing uniform particles.

[0062] In one embodiment, in the step (iii) of preparing a mixture by mixing the noble metal oxide and the ionomer, the type of the noble metal oxide is IrO. x(x is an integer from 1 to 3), RuO x (x is an integer from 1 to 3), PdO x (x is an integer from 1 to 3), IrMO x (M includes Ru, Sn, Ti, Te, Nb, or a combination thereof, and x is an integer from 1 to 3), or a combination thereof, preferably IrO x It can be. At this time, the fluorine-doped metal oxide may be included in an amount of 0.1 to 15 wt% based on 100 wt% of the total fluorine-doped metal oxide and noble metal oxide manufactured through the step (ii), for example, 0.2 to 15 wt%, 0.4 to 12 wt%, or 0.5 to 10 wt%. When the weight ratio of the fluorine-doped metal oxide and the noble metal oxide is within the above range, the oxygen evolution reaction catalyst including it can form a conductive network to reduce the sheet resistance of the electrode and improve the performance of the water electrolysis cell.

[0063] The ionomer may be a cationic conductor having a cationic exchange group capable of exchanging cations, or an anionic conductor having an anionic exchange group capable of exchanging anions such as hydroxyl ions, carbonates or bicarbonates.

[0064] The above cation exchange group may be any one selected from the group consisting of a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, and combinations thereof, and may generally be a sulfonic acid group or a carboxyl group.

[0065] The above cation conductor may include the above cation exchange group, and may include a fluorine-based polymer containing fluorine in the main chain; a hydrocarbon-based polymer such as benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyarylethersulfone, polyphosphazene or polyphenylquinoxaline; a partially fluorinated polymer such as a polystyrene-graft-ethylenetetrafluoroethylene copolymer or a polystyrene-graft-polytetrafluoroethylene copolymer; and a sulfone imide.

[0066] In addition, the cation conductor may substitute H in the cation exchange group at the end of the side chain with Na, K, Li, Cs or tetrabutylammonium. When replacing H in the cation exchange group at the end of the side chain with Na, NaOH is used during the preparation of the carbon structure composition, and when replacing H with tetrabutylammonium, tetrabutylammonium hydroxide is used. K, Li or Cs may also be substituted using an appropriate compound.

[0067] As the above anion conductor, a polymer doped with a metal hydroxide can generally be used, and specifically, a metal hydroxide doped poly(ethersulfone), polystyrene, a vinyl polymer, poly(vinyl chloride), poly(vinylidene fluoride), poly(tetrafluoroethylene), poly(benzimidazole), or poly(ethylene glycol) can be used.

[0068] The ionomer may be included in an amount of 10 to 45 wt% based on 100 wt% of the total of the noble metal oxide and ionomer, for example, 10 to 40 wt%, 10 to 35 wt%, or 10 to 33 wt%. When the content of the ionomer is within the above range, the performance of the electrolysis cell is improved, and at the same time, there is an advantage in that aggregation between ionomers due to an excess of ionomer can be suppressed.

[0069] In one embodiment, after mixing the slurry and the fluorine-doped metal oxide in step (iv), in the dispersing step, the fluorine-doped metal oxide may be included in an amount of 0.1 to 15 wt%, for example, 0.2 to 15 wt%, 0.4 to 12 wt%, or 0.5 to 10 wt%, based on 100 wt% of the total of the slurry and the fluorine-doped metal oxide. After mixing the slurry and the fluorine-doped oxide in the above content range, the dispersion may be manufactured through any one dispersion method selected from ultrasonic dispersion, stirring, a three-roll mill, a ball mill, planetary stirring, high-pressure dispersion, and a mixing method thereof.

[0070] Membrane-electrode assembly for electrolysis cell

[0071] A membrane-electrode assembly for a water electrolysis cell according to one embodiment comprises a polymer electrolyte membrane, an oxygen generation electrode positioned on one side of the polymer electrolyte membrane, and a hydrogen generation electrode positioned on the other side of the polymer electrolyte membrane.

[0072] The membrane-electrode assembly for the above-described electrolysis cell is illustrated in FIG. 1. The membrane-electrode assembly (20) for the electrolysis cell according to FIG. 1 includes a polymer electrolyte membrane (25); an oxygen generation electrode (21) positioned on one side of the polymer electrolyte membrane; and a hydrogen generation electrode (22) positioned on the other side of the polymer electrolyte membrane.

[0073] Since the oxygen generation electrode has been described above, a detailed description thereof will be omitted, and the hydrogen generation electrode and the polymer electrolyte membrane will be described in detail.

[0074] hydrogen generation electrode

[0075] The above hydrogen generation electrode refers to an electrode where a hydrogen evolution reaction (HER) occurs, and the hydrogen generation electrode may include a catalyst for the hydrogen evolution reaction. The hydrogen evolution reaction catalyst may include active particles and a carrier, and the active particles may include a noble metal, and the noble metal may be a platinum-based noble metal.

[0076] The platinum-based precious metal may be platinum (Pt) and / or a Pt-M alloy. The M may be 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).

[0077] Specifically, the Pt-M alloy includes 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 Mixtures can be used.

[0078] The above-mentioned carrier may be a carbon-based carrier. The carbon-based carrier may be 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.

[0079] The above oxygen generation electrode and the hydrogen generation electrode may each include only a catalyst layer including an oxygen generation reaction catalyst and a hydrogen generation reaction catalyst, but may also include an electrode substrate together with the catalyst layer. At this time, the electrode substrate may serve to support the electrode and diffuse the fuel and oxidant to the catalyst layer. The electrode substrate is not specifically limited and any known electrode substrate may be used, but specifically, carbon paper, carbon cloth, carbon felt, or metal cloth (a porous film composed of a fiber-like metal cloth or a cloth formed of polymer fibers on which a metal film is formed on the surface) that can be used as a conductive substrate may be used. The electrode substrate may be one that has been water-repellent treated with a fluorine-based resin, in which case, the reactant diffusion efficiency may be prevented from being reduced by water generated during operation of the water electrolysis cell. As the above fluorine-based resin, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, fluorinated ethylene propylene, polychlorotrifluoroethylene or a copolymer thereof can be used.

[0080] The above oxygen generation electrode and the above hydrogen generation electrode may include a microporous layer in addition to the above-described catalyst layer and electrode substrate. The microporous layer serves to enhance the reactant diffusion effect, and may generally include a conductive powder having a small particle size, such as carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotube, carbon nanowire, carbon nano-horn, or carbon nano ring.

[0081] polymer electrolyte membrane

[0082] The polymer electrolyte membrane has an ion exchange function that transfers hydrogen ions generated at an oxygen generation electrode to a hydrogen generation reaction catalyst. According to one embodiment, the polymer electrolyte membrane may include a porous support including a plurality of pores, and an ion conductor filling the pores of the porous support.

[0083] The porous support may be a fluorinated support or a nanoweb support. The fluorinated support may correspond to, for example, expanded polytetrafluoroethylene (e-PTFE) having a microstructure of polymer fibrils or a microstructure in which nodes are interconnected by fibrils. In addition, a film having a microstructure of polymer fibrils without nodes may also be used as the porous support.

[0084] The fluorinated support may include a perfluorinated polymer. The porous support may correspond to a more porous and stronger porous support obtained by extruding dispersion polymerized PTFE into a tape in the presence of a lubricant and stretching the material obtained thereby. In addition, the amorphous content of the PTFE may be increased by heat treating the e-PTFE at a temperature exceeding the melting point of the PTFE (about 342°C). The e-PTFE film manufactured by the method may have micropores with various diameters and a porosity. The e-PTFE film manufactured by the method may have at least 35% pores, and the diameter of the micropores may be about 0.01 to 1 μm (micrometer).

[0085] The above nano web support may be a non-woven fibrous web composed of a plurality of randomly oriented fibers. The non-woven fibrous web refers to a sheet having a structure of individual fibers or filaments that are interlaid, but not in the same manner as a woven fabric. The non-woven fibrous web may be manufactured by carding, garnetting, air-laying, wet-laying, melt blowing, spun bonding, or stitch bonding.

[0086] The fibers may comprise one or more polymeric materials, and any material that is generally used as a fiber-forming polymeric material may be used, and specifically, a hydrocarbon-based fiber-forming polymeric material may be used. For example, the fiber-forming polymeric material may comprise a polyolefin such as polybutylene, polypropylene, and polyethylene, a polyester such as polyethylene terephthalate and polybutylene terephthalate, a polyamide (nylon-6 and nylon-6,6), a polyurethane polybutene, polylactic acid, polyvinyl alcohol, polyphenylene sulfide, polysulfone, a fluid crystalline polymer, polyethylene-co-vinylacetate, polyacrylonitrile, a cyclic polyolefin, polyoxymethylene, a polyolefin-based thermoplastic elastomer, or a combination thereof.

[0087] The above nano web support may be a support in which nano fibers are integrated in the form of a non-woven fabric containing a large number of pores.

[0088] The above nanofibers exhibit excellent chemical resistance and have hydrophobicity, so hydrocarbon polymers that are free from moisture-induced deformation in high-humidity environments can be preferably used. Specifically, the 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 mixtures thereof.

[0089] The above nanoweb support is an aggregate of nanofibers manufactured by electrospinning and randomly arranged. At this time, the nanofibers may have an average diameter of 40 nm to 5000 nm when the average diameter of 50 fibers is measured using a scanning electron microscope (JSM6700F, JEOL) and calculated from the average, taking into account the porosity and thickness of the nanoweb. When the average diameter of the nanofibers is within the above range, the mechanical strength is excellent and an appropriate porosity can be secured.

[0090] The thickness of the nonwoven fibrous web may be 10 ㎛ to 50 ㎛ or 15 ㎛ to 43 ㎛. When the thickness of the nonwoven fibrous web is within the above range, the mechanical strength, weight reduction, and integration may be excellent. The nonwoven fibrous web may have a basic weight of 5 to 30 mg / cm. 2It can be. If the basis weight of the nonwoven fibrous web is less than the above numerical range, visible pores may be formed, making it difficult to function as a porous support, and if it exceeds the above numerical range, it may be manufactured in the form of paper or fabric in which pores are hardly formed. The porosity can be calculated by the ratio of the air volume in the porous support to the total volume of the porous support according to the following mathematical formula 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 and then subtracting the polymer volume calculated inversely from the density from the total volume.

[0091] [Mathematical Formula 1]

[0092] Porosity (%) = (air volume in porous support / total volume of porous support) X 100

[0093] For example, the porosity of the porous support may be 30 to 90%. When the porosity of the porous support is within the above range, problems such as a decrease in the impregnation property of the ion conductor or a problem of post-processing not proceeding smoothly due to a decrease in stability may not occur.

[0094] The above ion conductor is as described above. The ion conductor included in the polymer electrolyte membrane may be the same as or different from the ion conductor included in the oxygen generation electrode. For example, the ion conductor included in the polymer electrolyte membrane may be the same as the ion conductor included in the oxygen generation electrode.

[0095] Susan Haesel

[0096] In one embodiment, the electrolysis cell comprises a membrane-electrode assembly for the electrolysis cell.

[0097] The above electrolytic cell is the same as the known one except that it includes a membrane-electrode assembly according to one embodiment, so a detailed description is omitted.

[0098] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely illustrative of the present invention, and the present invention is not limited to the following examples.

[0099] Example 1

[0100] 1. Preparation of catalyst for oxygen generation reaction

[0101] Tetradecylamine (C 14 H 31 N)(95%) 1.28 g is dissolved in 160 ml of an aqueous ethanol solution (ethanol:water = 1:2.5), and then 20 ml of ethanol in which 5.21 g of tin tetrachloride (SnCl4) is dissolved is added and mixed for 1 hour. Next, the mixture is mixed in 200 ml of a 1.5 mM ammonia solution, and refluxed at 80°C for 72 hours, then washed using centrifugation and dried using a heat-drying or freeze-drying method. The dried powder is heat-treated in an air atmosphere at a temperature of 400°C for 3 hours to obtain SnO2 powder.

[0102] 1 g of the manufactured SnO2 powder and 0.25 g of NH4F, a fluorine precursor, were mixed to design the molar ratio of SnO2 and NH4F to 1:1, and then the powder particle size was homogeneously mixed to prepare a mixture. Here, the amount of fluorine doped can be controlled by adjusting the amount of the fluorine precursor and the manufactured SnO2 powder. The manufactured mixture was heat-treated at a temperature of 400°C for 6 hours in an inert gas atmosphere, and the heat-treated powder was washed and filtered using ethanol and distilled water, and then dried at a temperature of 60°C for 12 hours to prepare a conductive additive.

[0103] IrO xA catalyst slurry is prepared by mixing a catalyst and an ionomer solution so that the ionomer / catalyst ratio is 0.3. 2 wt% of the prepared conductive additive is added to the prepared catalyst slurry based on 100 wt% of the total catalyst slurry, dispersed, and stirred for 24 hours to prepare a catalyst composition for an oxygen generation reaction. The above-mentioned catalyst composition for an oxygen generation reaction is referred to as a first catalyst composition.

[0104] 2. Manufacturing of a membrane-electrode assembly containing a catalyst for oxygen evolution reaction

[0105] A second catalyst composition was prepared by mixing a catalyst having a platinum particle content of 46 wt% and an ionomer solution on a graphite carrier so that the ionomer / carbon ratio was 1.0. The first catalyst composition was thinly applied to a transfer substrate by spraying, decaling, or ultrasonic spray coating to prepare a first electrode, and the second catalyst composition was applied to another transfer substrate to prepare a second electrode. Then, the first electrode was transferred to one side of a polymer electrolyte membrane, and the second electrode was transferred to the opposite side and bonded to form a membrane-electrode assembly.

[0106] Example 2

[0107] In the manufacture of the catalyst for oxygen evolution reaction, the catalyst for oxygen evolution reaction and the membrane-electrode assembly were manufactured in substantially the same manner as in Example 1, except that the conductive additive was manufactured by designing the molar ratio of SnO2 and NH4F to 1:6 using 1.5 g of NH4F, a fluorine precursor.

[0108] Example 3

[0109] In the manufacture of the oxygen evolution reaction catalyst, the oxygen evolution reaction catalyst and membrane-electrode assembly were manufactured in substantially the same manner as in Example 1, except that the conductive additive was manufactured by using 3 g of NH4F, a fluorine precursor, and designing the molar ratio of SnO2 and NH4F to be 1:12.

[0110] Example 4

[0111] In the manufacture of the oxygen evolution reaction catalyst, the oxygen evolution reaction catalyst and membrane-electrode assembly were manufactured in substantially the same manner as in Example 1, except that the conductive additive was manufactured by designing the molar ratio of SnO2 and NH4F to 1:15 using 3.7 g of NH4F, a fluorine precursor.

[0112] Example 5

[0113] In the manufacture of the oxygen evolution reaction catalyst, the oxygen evolution reaction catalyst and membrane-electrode assembly were manufactured in substantially the same manner as in Example 1, except that the conductive additive was manufactured by designing the molar ratio of SnO2 and NH4F to 1:20 using 5 g of NH4F, a fluorine precursor.

[0114] Example 6

[0115] A solution is prepared by dissolving 3 g of polyvinylpyrolidone (PVP) in 40 ml of methanol and then dissolving 0.1 g of tin tetrachloride (SnCl4). A high voltage (15 kV) is applied to the metal nozzle of the prepared solution using a single nozzle electrospinning system to obtain a wire-shaped wire emitter, which is then washed and thermally dried. The prepared wire emitter is heat-treated in an air atmosphere at 400°C for 3 hours to obtain SnO2 powder.

[0116] A mixture was prepared by using 1 g of the obtained SnO2 powder and 5 g of NH4F, a fluorine precursor, at a molar ratio of 1:20, and then homogeneously mixing the powders to a particle size of 150 μm. The prepared mixture was heat-treated at 400°C for 6 hours in an inert gas atmosphere, and the heat-treated powder was washed and filtered using ethanol and distilled water, and then dried at 60°C for 12 hours to prepare a conductive additive. Thereafter, a catalyst for oxygen evolution reaction and a membrane-electrode assembly were prepared in substantially the same manner as in Example 1.

[0117] Comparative Example 1

[0118] Tetradecylamine (C 14 H 31 N)(95%) 1.28 g was dissolved in 160 ml of an aqueous ethanol solution (ethanol:water = 1:2.5), and then 30 ml of ethanol in which 2.75 g of tin tetrachloride (SnCl4) and 0.40 g of NH4F were dissolved was added and mixed for 1 hour. Next, the mixture was mixed in 200 ml of a 1.5 mM ammonia solution, refluxed at 80°C for 72 hours, washed using centrifugation, and dried using a thermal drying or freeze drying method. The dried powder was heat-treated in an air atmosphere at 400°C for 3 hours to prepare a conductive additive. Thereafter, a catalyst for an oxygen evolution reaction and a membrane-electrode assembly were prepared in substantially the same manner as in Example 1.

[0119] Comparative Example 2

[0120] Tetradecylamine (C 14 H 31 N)(95%) 1.28g was dissolved in 160 ml of aqueous ethanol solution (ethanol:water = 1:2.5), and then 2.8g of tin tetrachloride (Tin tetrachloride; SnCl4) and niobium ethoxide (Niobium(V) ethoxide; C 10 H 25 NbO5) 0.49 g dissolved in 30 ml of ethanol is added and mixed for 1 hour. Next, the mixture is mixed with 200 ml of a 1.5 mM ammonia solution, refluxed at 80°C for 72 hours, washed using centrifugation, and dried using a thermal drying or freeze drying method. The dried powder is heat-treated in an air atmosphere at 400°C for 3 hours to produce a conductive additive. Thereafter, a catalyst for oxygen generation reaction and a membrane-electrode assembly were produced in substantially the same manner as in Example 1.

[0121] Comparative Example 3

[0122] Tetradecylamine (C 14 H 31 N)(95%) 2.5 g was dissolved in 160 ml of an aqueous ethanol solution (ethanol:water = 1:2.5), and then 60 ml of ethanol in which 0.3 g of tin tetrachloride (SnCl4) and 4.3 g of indium chloride (InCl3) were dissolved were added, and the mixture was stirred and mixed for 1 hour. Next, the mixture was mixed in 200 ml of a 1.5 mM ammonia solution, and the mixture was refluxed at 80°C for 72 hours, washed using centrifugation, and dried using a thermal drying or freeze drying method. The dried powder was heat-treated in an air atmosphere at 400°C for 3 hours to prepare a conductive additive. Thereafter, a catalyst for an oxygen evolution reaction and a membrane-electrode assembly were prepared in substantially the same manner as in Example 1.

[0123] Evaluation Example 1: Fluorine Content Analysis

[0124] In order to confirm the degree of fluorine doping of the fluorine-doped metal oxide in the conductive additives manufactured in the examples and comparative examples, the fluorine atoms measured by X-ray photoelectron spectroscopy (XPS) were confirmed as a fraction in the entire fluorine-doped metal oxide, and the results are shown in Table 1.

[0125] Evaluation Example 2: Electrical Conductivity Evaluation

[0126] The first electrode manufactured in the examples and comparative examples was cut to 2 cm x 2 cm, and then electrodes were made with silver plates at both corners, and the surface resistance was measured using the van der pauw surface resistance measurement method to evaluate the electrical conductivity, and the results are shown in Table 1.

[0127] Fluorine content (at%) Electrical conductivity (mS / cm) Example 11.13.38 Example 26.26.69 Example 38.712.12 Example 49.614.28 Example 510.116.26 Example 610.326.78 Comparative Example 10.70.001 Comparative Example 2-0.55 Comparative Example 3-0.8

[0128] Referring to Table 1, it can be confirmed that Examples 1 to 6, which were manufactured by mixing NH4F in a solid state and then heat-treating it, have superior electrical conductivity compared to Comparative Example 1, which was manufactured by dissolving NH4F, a fluorine precursor, in a solution. In addition, it can be confirmed that electrical conductivity can be controlled by adjusting the molar ratio of NH4F.

[0129] In addition, it can be confirmed that the electrical conductivity of Examples 1 to 6 doped with fluorine is superior to that of Comparative Examples 2 and 3 doped with niobium or indium.

[0130] In addition, when the same amount of fluorine precursor was used, the electrical conductivity was measured according to the shape of the metal oxide, and it was confirmed that the electrical conductivity was improved in Example 6, in which fluorine was doped into a wire-shaped metal oxide, compared to Example 5, in which fluorine was doped into a sphere-shaped metal oxide.

[0131] Evaluation Example 3: Comparison of Performance Changes After Electrochemical Performance Evaluation and Deterioration Test

[0132] In order to evaluate the electrochemical performance of the electrolysis cell including the membrane-electrode assembly of Example 5, Comparative Example 2, and Comparative Example 3, the performance was evaluated by measuring the current and resistance at voltages from 1.4 V to 2 V while adding a flow rate of 5 ml / min of distilled water at 80°C, and the results are shown in Fig. 2. Afterwards, for the deterioration test, a constant current of 2.0 A / cm was measured at 80°C. 2 After 100 hours of degradation, the performance was evaluated by measuring the current and resistance at voltages from 1.4 V to 2 V, and the results are shown in Fig. 3.

[0133] Referring to Fig. 2, it can be confirmed that the highest initial water electrolysis performance was shown in Example 5 with fluorine doping compared to Comparative Examples 2 and 3, and it was confirmed that this showed the same tendency as the electrical conductivity tendency of the conductive additive.

[0134] Referring to Figure 3, when comparing the changed performance after a 100-hour deterioration test, it can be confirmed that the highest electrolysis performance was shown in Example 5 with fluorine doping compared to Comparative Examples 2 and 3.

[0135] Referring to Fig. 4, which shows both Fig. 2 showing the initial electrolysis performance and Fig. 3 showing the changed performance after a 100-hour degradation test, it can be seen that the range of performance change increases in the order of Example 5, Comparative Example 2, and Comparative Example 3, and it can be seen that the difference in performance change is large due to the change in the electrical conductivity of the electrode due to the elution of the doping element. In Fig. 4, BOL refers to the graph of Fig. 2 showing the initial electrolysis performance, and EOL refers to the graph of Fig. 3 showing the changed performance after a 100-hour degradation test.

[0136] Evaluation Example 4: ICP Comparison of Element Dissolution Amounts in the Electrolyte After the Electrochemical Deterioration Test

[0137] After the electrochemical degradation test of the electrolysis cell including the membrane-electrode assembly of Example 5, Comparative Example 2, and Comparative Example 3, the dissolved elements and their amounts in the electrolyte were analyzed, and the results are shown in Table 2.

[0138] Dissolved elemental tin (㎍ / cm) 2 )Doping element (㎍ / cm 2 )Example 50.20.1Comparative Example 27.52.0Comparative Example 32.318

[0139] Referring to Table 2, in the case of tin oxide coated with fluorine according to Example 5, it can be confirmed that the amount of doped fluorine as well as tin is reduced compared to tin oxide doped with a cation such as niobium or indium according to Comparative Examples 2 and 3.

[0140] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

Claims

1. Water electrolysis catalyst particles containing precious metal oxide; and A catalyst for oxygen evolution reaction in a water electrolysis cell, comprising a conductive additive containing a fluorine-doped metal oxide; A catalyst for oxygen evolution reaction in a water electrolysis cell having a fluorine content of 1 to 20 at% relative to 100 at% of the total components measured by X-ray photoelectron spectroscopy in the entire fluorine-doped metal oxide.

2. In paragraph 1, The above precious metal oxide is IrO x A catalyst for oxygen evolution reaction in a water electrolysis cell, wherein x is an integer from 1 to 3.

3. In paragraph 1, The above-mentioned water electrolysis catalyst particles are a catalyst for oxygen generation reaction of a water electrolysis cell supported on a carrier.

4. In paragraph 3, The average particle diameter (D) of the above water electrolysis catalyst particles 50 ) is a catalyst for oxygen evolution reaction in a water electrolysis cell having a particle size of 1 nm to 15 nm.

5. In paragraph 1, A catalyst for oxygen generation reaction of a water electrolysis cell, comprising 60 to 95 wt% of water electrolysis catalyst particles relative to 100 wt% of the total amount of the water electrolysis catalyst particles and conductive additives.

6. In paragraph 1, The metal oxide is a catalyst for oxygen evolution reaction in a water electrolysis cell including tungsten oxide, titanium oxide, nickel oxide, ruthenium oxide, tantalum oxide, tin oxide, cobalt oxide, or a combination thereof.

7. In paragraph 1, The above metal oxide is a catalyst for the oxygen evolution reaction of a water electrolysis cell, which is tin oxide.

8. In paragraph 1, The above conductive additive is a catalyst for oxygen generation reaction in a water electrolysis cell having a shape of a sphere or wire.

9. In paragraph 8, The average particle diameter (D) of the conductive additive having the above sphere shape 50 ) is a catalyst for oxygen generation reaction in a water electrolysis cell having a particle size of 0.05 ㎛ to 0.5 ㎛.

10. In paragraph 8, The length of the conductive additive having the shape of the above wire is 1 ㎛ to 200 ㎛, A catalyst for oxygen evolution reaction in a water electrolysis cell, wherein the diameter of the conductive additive having the shape of the above wire is 0.1 ㎛ to 1.0 ㎛.

11. In paragraph 1, A catalyst for oxygen generation reaction in a water electrolysis cell, comprising 0.1 to 15 wt% of a conductive additive relative to 100 wt% of the total amount of the electrolysis catalyst particles and the conductive additive.

12. An oxygen generation electrode including a catalyst for oxygen generation reaction of a water electrolysis cell according to Article 1. 13.(ⅰ) Step of manufacturing a metal oxide; (ⅱ) a step of mixing the metal oxide and the fluorine precursor and then performing a heat treatment to produce a metal oxide doped with fluorine; (ⅲ) a step of preparing a slurry by mixing a precious metal oxide and an ionomer; and (ⅳ) A method for manufacturing an oxygen generation electrode, comprising the step of mixing and dispersing the slurry and the fluorine-doped metal oxide.

14. In paragraph 13, A method for manufacturing an oxygen evolution electrode, wherein the above fluorine precursor comprises NH4F, NH4HF2, or a combination thereof.

15. In paragraph 13, The above fluorine precursor is a method for manufacturing an oxygen evolution electrode in a solid state.

16. In paragraph 13, A method for manufacturing an oxygen generation electrode, wherein in the above step (ii), the molar ratio of the metal oxide and the fluorine precursor is 1:0.1 to 1:

20.

17. Polymer electrolyte membrane; An oxygen generation electrode according to claim 12, positioned on one side of the polymer electrolyte membrane; and A membrane-electrode assembly for a water electrolysis cell, comprising a hydrogen generation electrode positioned on the other side of the polymer electrolyte membrane.

18. A water electrolysis cell comprising a membrane electrode assembly for a water electrolysis cell according to Article 17.

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