Alkaline water electrolysis membrane

Abstract

The present invention relates to an alkaline water electrolysis membrane in which the volume of a polymer mesh support included in the membrane is optimized, and thus defects such as mesh exposure, bending, and cracking do not occur when the membrane is fastened to a cell, and the mechanical properties and durability of the membrane are maintained.

Description

alkaline water electrolysis membrane

[0001] Cross-citation with related applications

[0002] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0170584 filed on November 26, 2024 and Korean Patent Application No. 10-2025-0171722 filed on November 13, 2025, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of the specification.

[0003] Technology field

[0004] The present invention relates to an alkaline water electrolysis membrane.

[0005]

[0006] Water electrolysis technology is a method of producing hydrogen in an eco-friendly manner by electrically decomposing water, and its high potential and importance as a clean energy source are being emphasized. The performance and durability of such water electrolysis systems are primarily determined by the characteristics of the membrane, and in particular, the durability and mechanical properties of the membrane have a significant impact on the stability and long-term performance of the system.

[0007] Water electrolysis systems are broadly classified into polymer electrolysis using polymer electrolyte membranes (PEM), alkaline electrolysis using alkaline aqueous solutions as electrolytes (AEC), anion electrolysis using anion exchange membranes (AEM), and solid oxide electrolysis using solid oxides as electrolytes (SOEC). Among these, alkaline electrolysis membranes used in alkaline electrolysis operate in an alkaline electrolyte environment and have the advantage of maintaining high mechanical strength and durability through their porous structure.

[0008] Conventional alkaline water electrolysis membranes were mainly composed of ceramic mixed compositions, but these compositions had problems with reduced mechanical properties and durability upon repeated use, causing the membranes to be easily damaged or deformed (curled, cracked), and these defects reduced the efficiency and stability of the electrolytic cell.

[0009] To solve this, a technology was introduced to insert a polymer mesh structure as a reinforcing support into a membrane composed solely of a ceramic mixed composition. While this polymer mesh has the effect of improving mechanical strength and durability by reinforcing the physical properties of the membrane, it was difficult to consistently ensure the performance of the membrane due to ambiguous optimization criteria for the polymer mesh.

[0010] Accordingly, there is a need for research on alkaline water electrolysis membranes that improve the mechanical strength and durability of the membrane while preventing defects by controlling the volume characteristics of the polymer mesh included in the membrane.

[0011]

[0012] The problem to be solved by the present invention is to provide an alkaline water electrolysis membrane that can exhibit low internal resistance and prevent defects such as mesh exposure, bending, and cracking when fastened to a cell, while maintaining the mechanical properties and durability of the membrane by optimizing the volume of the polymer mesh support itself included in the porous membrane.

[0013]

[0014] To solve the above-mentioned problem, the present invention provides an alkaline water electrolysis membrane.

[0015] More specifically, (1) the present invention provides an alkaline water electrolysis membrane comprising: a polymer mesh support; and a coating layer formed on the polymer mesh support and comprising ceramic particles and a polymer binder, wherein the volume percentage of the polymer mesh support calculated by the following formula 1 is 7% or more and 13% or less.

[0016] [Equation 1]

[0017] Volume percentage (%) = (Volume of polymer mesh support contained in unit cell / Volume of unit cell) * 100,

[0018] In the above Equation 1, the unit cell is a rectangular prism having a height corresponding to the thickness of the membrane, and a square formed by connecting the points where the longitudinal rotation axes of the vertical strands and the horizontal strands intersect when the two horizontal strands and two vertical strands of the polymer mesh support are arranged vertically.

[0019] (2) The present invention provides an alkaline water electrolysis membrane according to (1), wherein the volume percentage of the polymer mesh support is 7% or more and 11% or less.

[0020] (3) The present invention provides an alkaline water electrolysis membrane in which, in either (1) or (2) above, the polymer mesh support comprises one or more selected from the group consisting of polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSU), polyether ether ketone (PEEK), polypropylene (PP), polyether sulfone (PES), polyethylene terephthalate (PET), and polyamide (PA).

[0021] (4) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (3), the ceramic particles comprise one or more selected from the group consisting of ZrO2, NiO, Co3O4, TiO2, Fe3O4, CeO2, HfO2, Al2O3, SiO2 and Y2O3.

[0022] (5) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (4), the polymer binder comprises one or more selected from the group consisting of polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN) and polyethylene oxide (PEO).

[0023] (6) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (5), the ceramic particles are 50% by weight or more and 80% by weight or less, and the polymer binder is 10% by weight or more and 20% by weight or less, based on the total weight of the alkaline water electrolysis membrane.

[0024] (7) The present invention provides an alkaline water electrolysis membrane having a thickness of 150 μm or more and 600 μm or less, in any one of (1) to (6).

[0025] (8) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (7), the mesh number calculated as the number of unit cells per inch is 30 or more and 250 or less.

[0026] (9) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (8), the diameter of the polymer mesh support is 30 μm or more and 180 μm or less.

[0027] (10) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (9), the bottom surface of the unit cell is a square with a side length of 100 μm or more and 700 μm or less.

[0028] (11) The present invention provides an alkaline water electrolysis membrane in which, in any one of (1) to (10), when a pressure is applied to a membrane filled with water while gradually increasing the pressure from 0 bar using nitrogen gas, the bubble point pressure obtained by measuring the pressure at which bubbles are generated is 2 bar or more and 6 bar or less.

[0029]

[0030] The alkaline water electrolysis membrane according to the present invention includes a polymer mesh support as a reinforcing support, and the volume percentage of the polymer mesh support included in the unit cell is optimized so that no defects occur when the cell is connected, while maintaining the mechanical properties and durability of the membrane.

[0031]

[0032] FIG. 1 is a conceptual diagram showing the shape of a unit cell of the present invention in three dimensions.

[0033] FIG. 2 is a conceptual diagram showing a plan view of the membrane of the present invention as seen horizontally from above and a front view as seen from the front.

[0034]

[0035] The present invention will be described in more detail below.

[0036] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0037]

[0038] alkaline water electrolysis membrane

[0039] The present invention provides an alkaline water electrolysis membrane comprising: a polymer mesh support; and a coating layer formed on the polymer mesh support and comprising ceramic particles and a polymer binder, wherein the volume percentage of the polymer mesh support calculated by Formula 1 below is 7 to 13%.

[0040] [Equation 1]

[0041] Volume percentage (%) = (Volume of polymer mesh support contained in unit cell / Volume of unit cell) * 100,

[0042] In the above Equation 1, the unit cell is a rectangular prism having a height corresponding to the thickness of the membrane, and a square formed by connecting the points where the longitudinal rotation axes of the vertical strands and the horizontal strands intersect when the two horizontal strands and two vertical strands of the polymer mesh support are arranged vertically.

[0043]

[0044] The alkaline water electrolysis membrane of the present invention will be described in detail below.

[0045] The polymer mesh support included in the alkaline water electrolysis membrane of the present invention supports the membrane and performs the role of improving mechanical properties and durability. The polymer mesh support may include one or more selected from the group consisting of polyphenylene sulfide mesh (PPS Mesh), polytetrafluoroethylene mesh (PTFE Mesh), polysulfone mesh (PSU Mesh), polyether ether ketone mesh (PEEK Mesh), polypropylene mesh (PP Mesh), polyether sulfone (PES), polyethylene terephthalate (PET), and polyamide (PA), and preferably may be polyphenylene sulfide mesh (PPS Mesh). When the above polymer mesh support is appropriately selected, the membrane can be kept chemically stable even in an alkaline environment, which can increase the lifespan of the membrane and increase ion conductivity. Additionally, the pore structure and density of the membrane can be optimized, which can lead to increased cell coupling suitability and reduced gas crossover.

[0046] The ceramic particles included in the alkaline water electrolysis membrane of the present invention serve to provide a pathway for ion conduction and increase mechanical stability. Specifically, the ceramic particles may include one or more selected from the group consisting of ZrO2, NiO, Co3O4, TiO2, Fe3O4, CeO2, HfO2, Al2O3, SiO2, and Y2O3, and preferably may be ZrO2. When the ceramic particles are appropriately selected, the efficiency of the alkaline water electrolysis reaction can be increased, and the thermal stability of the membrane can be enhanced to maintain stable performance even at high temperatures.

[0047] The polymer binder included in the alkaline water electrolysis membrane of the present invention can provide structural and electrochemical stability to the membrane and perform the role of blocking gas, and specifically may include one or more selected from the group consisting of polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polyethylene oxide (PEO). When the polymer binder is appropriately selected, the performance and durability of the membrane can be significantly improved, and the gas blocking function can be enhanced to reduce gas crossover.

[0048] The alkaline water electrolysis membrane of the present invention may include a coating layer formed on the polymer mesh support and comprising a polymer binder and ceramic particles. The content of the ceramic particles may be 50 wt% or more, 51 wt% or more, 52 wt% or more, 53 wt% or more, 54 wt% or more, 55 wt% or more, 56 wt% or more, 57 wt% or more, 58 wt% or more, 59 wt% or more, or 60 wt% or more, and 80 wt% or less, 79 wt% or less, 78 wt% or less, 77 wt% or less, 76 wt% or less, 75 wt% or less, 74 wt% or less, 73 wt% or less, 72 wt% or less, 71 wt% or less, or 70 wt% or less.

[0049] In addition, the content of the polymer binder may be 10 wt% or more, 11 wt% or more, 12 wt% or more, 13 wt% or more, or 14 wt% or more, and 20 wt% or less, 19 wt% or less, 18 wt% or less, 17 wt% or less, 16 wt% or less, or 15 wt% or less, based on the total weight of the alkaline water electrolysis membrane.

[0050] When the content of polymer binder and ceramic particles is maintained appropriately, the mechanical strength and durability of the membrane can be improved, and the ion conductivity can be optimized, which can significantly improve the performance and stability of the overall water electrolysis system.

[0051] Additionally, the coating layer may include a polymer additive capable of promoting pore formation. Specifically, the polymer additive may include one or more selected from the group consisting of polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetate, glycerol, and triethylene glycol, and preferably may be polyvinylpyrrolidone.

[0052] The content of the above polymer additive may be 0.1 wt% or more, 0.2 wt% or more, 0.3 wt% or more, 0.4 wt% or more, or 0.5 wt% or more, and 2.5 wt% or less, 2.4 wt% or less, 2.3 wt% or less, 2.2 wt% or less, 2.1 wt% or less, or 2.0 wt% or less, based on the total weight of the alkaline water electrolysis membrane.

[0053] The volume percentage of the polymer mesh support included in the alkaline water electrolysis membrane of the present invention may be 7% or more and 13% or less, preferably 7.0% or more, 7.2% or more, 7.4% or more, 7.6% or more, 7.8% or more, 8.0% or more, 8.2% or more, 8.4% or more, 8.6% or more, 8.8% or more, or 9.0% or more, and may be 13.0% or less, 12.8% or less, 12.6% or less, 12.4% or less, 12.2% or less, 12.0% or less, 11.8% or less, 11.6% or less, 11.4% or less, 11.2% or less, 11.0% or less, 10.8% or less, or 10.6% or less. When the volume percentage of the polymer mesh support is maintained within the above range, defects caused by curl, cracking, or exposure of the polymer mesh during cell assembly can be minimized, thereby enabling stable cell assembly while improving the mechanical properties and durability of the membrane. In addition, the internal resistance of the cell is low, so the voltage efficiency can be particularly excellent.

[0054] The above unit cell is defined as a rectangular prism having a height corresponding to the thickness of the membrane, and having a square base formed by connecting the points where the longitudinal rotation axes of the vertical and horizontal strands intersect when two horizontal strands and two vertical strands of the polymer mesh support are arranged vertically. The volume of the unit cell can be obtained by multiplying the area of ​​the base by the thickness of the membrane.

[0055] Specifically, the base of the unit cell may be a square, and the length of one side of the square may be 100 µm or more and 700 µm or less, preferably 100 µm or more, 110 µm or more, 120 µm or more, 130 µm or more, 140 µm or more, or 150 µm or more, and may be 300 µm or less, 290 µm or less, 280 µm or less, 270 µm or less, 260 µm or less, 250 µm or less, 240 µm or less, 230 µm or less, 220 µm or less, 210 µm or less, or 200 µm or less. The length of one side of the square may be defined as the length of the unit cell.

[0056] In addition, the wire diameter of the polymer mesh support included in the unit cell may be 30㎛ or more and 180㎛ or less, preferably 30㎛ or more, 32㎛ or more, 34㎛ or more, 36㎛ or more, 38㎛ or more, 40㎛ or more, 42㎛ or more, 44㎛ or more, 46㎛ or more, 48㎛ or more, or 50㎛ or more, and may be 80㎛ or less, 78㎛ or less, 76㎛ or less, 74㎛ or less, 72㎛ or less, 70㎛ or less, 68㎛ or less, 66㎛ or less, 64㎛ or less, 62㎛ or less, or 60㎛ or less.

[0057] When the length of one side of the bottom surface of the unit cell and the wire diameter of the polymer mesh support are maintained within the above range, the membrane can maintain an appropriate thickness, and the porosity and mechanical properties of the membrane can be improved.

[0058] The thickness of the alkaline water electrolysis membrane of the present invention may be 150 μm or more and 600 μm or less, preferably 150 μm or more, 160 μm or more, 170 μm or more, 180 μm or more, 190 μm or more, or 200 μm or more, and may be 350 μm or less, 340 μm or less, 330 μm or less, 320 μm or less, 310 μm or less, 300 μm or less, 290 μm or less, 280 μm or less, 270 μm or less, 260 μm or less, or 250 μm or less. The thickness of the membrane may be controlled by the coating gap, and when the thickness is maintained within the above range, the durability and mechanical strength of the membrane may be enhanced, the bubble point pressure may be optimized, and it may lead to a reduction in the internal resistance of the cell.

[0059] The mesh number of the alkaline water electrolysis membrane of the present invention may be 30 or more and 250 or less, preferably 100 or more, 110 or more, 120 or more, 130 or more, or 140 or more, and may be 200 or less, 190 or less, 180 or less, 170 or less, or 160 or less. When the mesh number is appropriately maintained, the mechanical strength of the membrane can be increased to improve durability, and ion conductivity can be appropriately maintained.

[0060] The thickness, mesh number, wire diameter, and side length of the unit cell of the above alkaline water electrolysis membrane can be measured using a thickness gauge and a microscope. Specifically, the thickness of the membrane can be calculated as the average value obtained by measuring at five points using a contact thickness gauge (Teclock, PG-02). In addition, the unit cell length according to the mesh number can be calculated by averaging the values ​​measured at three or more points using an optical microscope (100x magnification, using a calibrator). Furthermore, the wire diameter can be calculated as the average value of the diameters measured at three or more points using image analysis software after photographing the cross-section of the strand using an optical microscope (100x magnification, using a calibrator).

[0061] In addition, the bubble point pressure of the alkaline water electrolysis membrane of the present invention may be 2 bar or more and 6 bar or less, preferably 2.0 bar or more, 2.1 bar or more, 2.2 bar or more, 2.3 bar or more, 2.4 bar or more, or 2.5 bar or more, and may be 4 bar or less, 3.9 bar or less, 3.8 bar or less, 3.7 bar or less, 3.6 bar or less, or 3.5 bar or less. When the bubble point pressure of the membrane is maintained within the above range, gas crossover can be prevented due to excellent pore characteristics, stable ion conductivity and electrolyte stability can be secured, and it can lead to increased mechanical strength and durability.

[0062]

[0063] Hereinafter, the present invention will be described in more detail through examples and experimental examples to specifically explain the invention, but the present invention is not limited by these examples and experimental examples. The embodiments according to the present invention may be modified in various different forms, and the scope of the present invention should not be interpreted as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the invention to those with average knowledge in the art.

[0064]

[0065] Example 1

[0066] A slurry containing 40 g of ZrO2 and 7.5 g of a polysulfone polymer binder was double-sidedly coated onto a polyphenylene sulfide mesh with a mesh number of 120 and a wire diameter of 55 μm using a tape casting method. Subsequently, the polymer mesh coated with the slurry was hot-air dried at 90°C for 15 minutes, and the dried polymer substrate was immersed in water, a non-solvent, to form phase separation and pores at 5°C for 10 hours. An alkaline water electrolysis membrane was then prepared through a washing process. The final thickness of the prepared membrane was 300 μm.

[0067]

[0068] Example 2

[0069] In the above Example 1, an alkaline water electrolysis membrane was prepared in the same manner as in Example 1, except that a polyphenylene sulfide mesh with a mesh number of 150 and a wire diameter of 50 μm was used and the thickness of the final membrane was 250 μm.

[0070]

[0071] Example 3

[0072] In the above Example 1, an alkaline water electrolysis membrane was prepared in the same manner as in Example 1, except that the thickness of the final membrane was 220 μm.

[0073]

[0074] Example 4

[0075] In the above Example 1, an alkaline water electrolysis membrane was prepared in the same manner as in Example 1, except that a polyphenylene sulfide mesh with a mesh number of 150 was used and the thickness of the final membrane was 220 μm.

[0076]

[0077] Comparative Example 1

[0078] In the above Example 1, an alkaline water electrolysis membrane was prepared in the same manner as in Example 1, except that a polyphenylene sulfide mesh with a mesh number of 150 and a wire diameter of 50 μm was used and the thickness of the final membrane was 350 μm.

[0079]

[0080] Comparative Example 2

[0081] In the above Example 1, an alkaline water electrolysis membrane was prepared in the same manner as in Example 1, except that the thickness of the final membrane was 160 μm.

[0082]

[0083] Experimental Example 1: Calculation of Unit Cell Volume Percentage

[0084] The thickness, mesh number, wire diameter, and unit cell length of the membranes prepared in the above examples and comparative examples are shown in Table 1 below. In this case, the thickness of the membrane was calculated as the average of values ​​measured at five points using a contact thickness gauge (Teclock, PG-02). Additionally, the unit cell length was calculated as the average of values ​​measured at three or more points using an optical microscope (100x magnification, using a calibrator). Furthermore, the wire diameter of the mesh strand was calculated as the average of diameter values ​​measured at three or more points using image analysis software after photographing the strand cross-section using the same microscope.

[0085] At this time, the unit cell was defined as a rectangular prism having a height corresponding to the thickness of the membrane, and a square formed by connecting the points where the longitudinal rotation axes of the vertical and horizontal strands intersect when the two horizontal strands and two vertical strands of the polymer mesh support are arranged vertically.

[0086] In addition, the unit cell volume of the membrane prepared in the above examples and comparative examples and the volume of the polymer mesh support included in the unit cell were each calculated, and the volume percentage of the polymer mesh support was calculated from this and shown in Table 2 below.

[0087]

[0088] Membrane Thickness [㎛] Mesh Number Line Diameter [㎛] Unit Cell Length [㎛] Example 1 300 1205 5212 Example 2 250 150 50 169 Example 3 220 1205 5212 Example 4 220 150 55 169 Comparative Example 1 350 150 50 169 Comparative Example 2 160 1205 5212

[0089]

[0090] Polymer mesh support volume (A) [㎛ 3 ] Unit cell volume (B) [㎛ 3] Volume Percentage ((A / B)*100) [%] Example 1 1,005,768 13,440,833 7.48 Example 2 664,970 7,168,444 9.28 Example 3 1,005,768 9,856,611 10.20 Example 4 804,614 6,308,231 12.75 Comparative Example 1 664,970 10,035,822 6.63 Comparative Example 21,005,768 7,168,444 14.03

[0091]

[0092] Experimental Example 2: Measurement of bubble point pressure of a membrane

[0093] To comprehensively evaluate the pore characteristics and durability of the membrane, the bubble point pressure of the membranes of the examples and comparative examples was measured by the following method, and the results were summarized in Table 3 below.

[0094]

[0095] [measurement method]

[0096] Bubble point pressure [bar]: After cutting the prepared membrane to fit the diameter of the nitrogen cylinder, the membrane is attached to a measuring cell, water is filled on one side, and a pressure gradually increasing from 0 bar is applied to the other side using nitrogen gas. At this time, the pressure at which the first bubble appears on the opposite side after passing through the membrane is measured as the bubble point pressure.

[0097]

[0098] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Bubble point pressure [bar] 2.5 2.5 2.9 2.5 2.9 1.3

[0099]

[0100] As can be seen from Table 3 above, the membranes of Examples 1 to 4 of the present invention generally show higher bubble point pressures compared to the comparative examples, and in particular, the membrane of Comparative Example 2 shows a significantly lower bubble point pressure because the polymer mesh support is exposed to the surface. From these results, it was found that the membrane of the present invention has excellent pore stability.

[0101]

[0102] Experimental Example 3: Evaluation of Membrane-Applied Cells

[0103] To determine the cell coupling suitability of the membranes manufactured in the above examples and comparative examples, the cell coupling suitability was evaluated using the measurement method described below. In addition, a High Frequency Resistance (HFR) cell evaluation was conducted to objectively verify the internal cell resistance.

[0104]

[0105] [measurement method]

[0106] 1) Evaluation of cell connection suitability

[0107] Effective evaluation area 5*5cm 2 Based on [the reference point], the membrane was placed in the center, and the nickel foam electrode was fixed as a load cell. Subsequently, cell evaluation (constant current condition (0.6A / cm²) was performed while maintaining the electrolyte KOH at a temperature of 80℃ and a flow rate of 500mL / min. 2 After maintaining performance until stabilization, IV curve measurement was performed. In addition, the suitability of cell assembly was determined by checking the degree of electrolyte leakage caused by membrane damage (cracks or wrinkles) during cell assembly.

[0108]

[0109] [Judgment Criteria]

[0110] Excellent (◎): No issues with cell evaluation (stable data collection possible during IV curve measurement), excellent appearance without tearing or membrane separation, etc.

[0111] Good (○): No issues with cell evaluation (stable data collection possible during IV curve measurement), partial membrane tearing around the cell connection point during membrane disassembly

[0112] Defective (X): Cell evaluation impossible (data instability during IV curve measurement, short circuit), electrolyte leakage due to membrane damage such as cracks, wrinkles, or folds when the load cell is connected

[0113]

[0114] 2) HFR (High Frequency Resistance) Cell Evaluation

[0115] High Frequency Resistance (HFR) was measured using Electrochemical Impedance Spectroscopy (EIS). The membrane has an effective area of ​​2 x 2 cm². 2 After cutting to the desired shape, it was placed between nickel plate electrodes and fixed at a constant pressure using a load cell. A 30 wt% aqueous KOH solution was used as the electrolyte, and the electrolyte was circulated under conditions of 80°C and a flow rate of 500 mL / min. EIS measurements were performed at a constant current density of 1 A / cm². 2 The experiment was conducted in a frequency range from 1 Hz to 1 MHz under the conditions. The acquired impedance data was analyzed using a Nyquist plot, and the resistance value appearing near the real axis on the Nyquist plot was measured as the ionic resistance component (HFR) of the membrane.

[0116]

[0117] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Judgment Result ○○◎○XX Ion Resistance [Ω·cm 2 ]< 0.15< 0.15< 0.12< 0.15> 0.2> 0.2

[0118]

[0119] As can be seen from Table 4 above, in the case of Examples 1 to 4, which are membranes satisfying the volume characteristics of the present invention, the cell judgment results are all good / excellent, and it can be confirmed that the membrane ion resistance value is low.

[0120] In comparison, in Comparative Example 1, where the volume percentage [%] of the polymer mesh support was less than 7, defects such as curl or crack occurred, and in Comparative Example 2, where the volume percentage [%] of the polymer mesh support was greater than 13, leakage of KOH occurred when the cell was connected. In addition, it was confirmed that both Comparative Examples 1 and 2 showed high membrane ion resistance, making them unsuitable for application in water electrolysis cells.

[0121] From these results, it was found that the membrane of the present invention has an optimized volume percentage of the mesh support, excellent cell fastening suitability and membrane ion resistance characteristics, and is suitable for application in a water electrolysis system.

Claims

1. Polymer mesh support; and A coating layer formed on the above polymer mesh support and comprising ceramic particles and a polymer binder, and An alkaline water electrolysis membrane having a volume percentage of a polymer mesh support calculated by Formula 1 below of 7% or more and 13% or less. [Equation 1] Volume percentage (%) = (Volume of polymer mesh support contained in unit cell / Volume of unit cell) * 100, In the above Equation 1, the unit cell is a rectangular prism having a height corresponding to the thickness of the membrane, and includes a square formed by connecting the points where the longitudinal rotation axes of the vertical strands and the horizontal strands intersect when two horizontal strands and two vertical strands of the polymer mesh support are arranged vertically.

2. In Claim 1, An alkaline water electrolysis membrane having a volume percentage of the polymer mesh support of 7% or more and 11% or less.

3. In Claim 1, The above-mentioned polymer mesh support comprises one or more selected from the group consisting of polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone (PSU), polyether ether ketone (PEEK), polypropylene (PP), polyether sulfone (PES), polyethylene terephthalate (PET), and polyamide (PA), an alkaline water electrolysis membrane.

4. In Claim 1, An alkaline water electrolysis membrane comprising one or more types selected from the group consisting of ZrO2, NiO, Co3O4, TiO2, Fe3O4, CeO2, HfO2, Al2O3, SiO2, and Y2O3, wherein the ceramic particles are an alkaline water electrolysis membrane.

5. In Claim 1, The above-mentioned polymer binder comprises one or more selected from the group consisting of polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polyethylene oxide (PEO), an alkaline water electrolysis membrane.

6. In Claim 1, Based on the total weight of the alkaline water electrolysis membrane, Ceramic particles of 50 weight% or more and 80 weight% or less, Alkaline water electrolysis membrane containing 10% by weight or more and 20% by weight or less of a polymer binder.

7. In Claim 1, Alkaline water electrolysis membrane having a thickness of 150㎛ or more and 600㎛ or less.

8. In Claim 1, An alkaline water electrolysis membrane having a mesh number calculated as the number of unit cells per inch of 30 or more and 250 or less.

9. In Claim 1, Alkaline water electrolysis membrane having a polymer mesh support with a wire diameter of 30㎛ or more and 180㎛ or less.

10. In Claim 1, An alkaline water electrolysis membrane, wherein the bottom surface of the above unit cell is a square with a side length of 100㎛ or more and 700㎛ or less.

11. In Claim 1, An alkaline water electrolysis membrane having a bubble point pressure of 2 bar or more and 6 bar or less, obtained by measuring the pressure at which bubbles are generated when nitrogen gas is applied to a membrane filled with water while gradually increasing the pressure from 0 bar.

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