Evaluation method and evaluation system of proton exchange membrane electrode for water electrolysis

Abstract

The invention provides an evaluation method and an evaluation system of proton exchange membrane electrodes for water electrolysis. The evaluation method at least comprises the following steps: providing a plurality of proton exchange membrane electrodes; performing different performance tests on the proton exchange membrane electrode to obtain a plurality of performance test data; performing data processing on each piece of performance test data to obtain a plurality of pieces of performance index data; and evaluating the comprehensive performance of the proton exchange membrane based on the multiple pieces of performance index data. According to the evaluation method and the evaluation system of the proton exchange membrane electrode for water electrolysis, provided by the invention, a unified, comprehensive and objective industrial standard can be provided for the performance test of the proton exchange membrane electrode, the proton exchange membrane electrode can be comprehensively evaluated, and a reliable reference is provided for the selection of an electrolysis electrode for water electrolysis.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology through water electrolysis, specifically to an evaluation method and system for proton exchange membrane electrodes used in water electrolysis. Background Technology

[0002] As the global energy crisis intensifies, hydrogen energy, as one of the most sustainable and cleanest energy sources, is receiving increasing attention. Water electrolysis, as a mature energy conversion technology, provides a simple, effective, and promising method for hydrogen production. Among water electrolysis technologies, proton exchange membrane (PEM) electrolysis uses a proton exchange membrane as the membrane electrode, enabling efficient production of high-purity hydrogen gas with no pollution generated during the electrolysis process. However, it places stringent requirements on the performance of the proton exchange membrane, and differences in membrane performance significantly impact the electrolysis of water. Therefore, performance testing of the proton exchange membrane is essential. However, there is currently no unified, comprehensive, and objective standard in the industry for proton exchange membrane performance testing. Summary of the Invention

[0003] This invention proposes an evaluation method and system for proton exchange membrane electrodes used in water electrolysis, which can provide a unified, comprehensive and objective industry standard for the performance testing of proton exchange membrane electrodes and provide a reliable reference for the selection of electrolysis electrodes for water electrolysis.

[0004] To address the aforementioned technical problems, this invention provides a method for evaluating a proton exchange membrane electrode for water electrolysis, comprising at least the following steps: Provides multiple proton exchange membrane electrodes; Different performance tests were performed on the proton exchange membrane electrode to obtain multiple performance test data. The performance test data are processed to obtain multiple performance index data; and The overall performance of the proton exchange membrane is evaluated based on multiple performance index data.

[0005] In one embodiment of the present invention, the performance tests include noble metal loading test, thickness test, hydrogen permeability test, ohmic resistance test, electrochemical active area test, polarization curve test and chemical stability test.

[0006] In one embodiment of the present invention, the noble metal loading test is performed by measuring the concentration of noble metals in the proton exchange membrane electrode and calculating the noble metal loading data.

[0007] In one embodiment of the present invention, the formula for calculating the precious metal loading data is as follows: L Pt / Ir =n×C Pt / Ir ×V Pt / Ir / S MEA ; Among them, L Pt / Ir This refers to the loading of noble metals in a proton exchange membrane electrode, expressed in milligrams per square centimeter (mg / cm²). 2 ), where n is the dilution factor for preparing the test sample into an ICP analysis solution, and C Pt / Ir V represents the concentration of precious metals in the ICP test solution, expressed in milligrams per liter (mg / L). Pt / Ir The initial volume of the prepared test sample, in liters (L), S MEA The effective area of ​​the proton exchange membrane electrode is expressed in square centimeters (cm²). 2 ).

[0008] In one embodiment of the present invention, the noble metal loading test measures the noble metal loading at multiple test points on the proton exchange membrane electrode to obtain the relative deviation of the noble metal loading, so as to evaluate the uniformity of the noble metal loading on the proton exchange membrane electrode.

[0009] In one embodiment of the present invention, before performing the electrochemical active area test, the polarization curve test, or the chemical stability test, at least the following steps are included: The proton exchange membrane electrode is installed in the electrolytic cell to complete the assembly of the electrolytic cell; The electrolytic cell was tested for leaks. Connect the electrolytic cell to the test bench; and The proton exchange membrane electrode is activated.

[0010] In one embodiment of the present invention, the electrochemical active area is tested by scanning the electrolytic cell using cyclic voltammetry, applying a voltage to the proton exchange membrane electrode to obtain a cyclic voltammetric curve, and then processing the data to calculate the electrochemical active area. The formula for calculating the electrochemical active area is as follows: S ECA =0.1×S H / (Q r ×v×M Pt ); Among them, S ECA The electrochemically active area of ​​platinum in a proton exchange membrane electrode is expressed in square meters per gram (m²). 2 / g), S H Q represents the peak area of ​​hydrogen oxidation-desorption on the cyclic voltammetry curve, in Ampere-volts (A·V). r The adsorption charge constant for hydroxide on a smooth Pt surface is 0.21 millicoulombs per square centimeter (0.21 mC / cm²). 2 ), v is the cyclic voltammetric scan rate, in volts per second (V / s), M Pt The mass of Pt in the proton exchange membrane electrode is expressed in grams (g).

[0011] In one embodiment of the present invention, the polarization curve test is performed by applying a constant current to the electrolytic cell and measuring the current, voltage, outlet temperature, hydrogen pressure, and hydrogen production of the electrolytic cell to obtain polarization performance test data.

[0012] In one embodiment of the present invention, the chemical stability test is performed by loading the proton exchange membrane electrode to a preset current density, periodically recording the voltage of the electrolyzer, obtaining chemical stability test data, and calculating the voltage decay rate to obtain chemical stability index data.

[0013] The present invention also provides an evaluation system for a proton exchange membrane electrode for water electrolysis, comprising at least: The test unit is used to test the performance of proton exchange membrane electrodes; A performance test data reading unit is electrically connected to the test unit and is used to obtain performance test data of the proton exchange membrane electrode in different tests. A data processing unit, electrically connected to the performance test data reading unit, is used to process the performance test data to obtain performance index data; and The evaluation unit, electrically connected to the data processing unit, is used to comprehensively evaluate the performance index data.

[0014] In summary, this invention proposes an evaluation method and system for proton exchange membrane electrodes (PEMEEs) used in water electrolysis. By conducting multiple performance tests on the PEMEE, multiple performance test data are obtained. These data are then processed to obtain multiple performance index data, which are used as the basis for a comprehensive evaluation of the PEMEE's performance, providing a reliable reference for the selection of PEMEEs for water electrolysis. Furthermore, the evaluation method provided by this invention, by defining the process for each performance test, can provide a unified, comprehensive, and objective industry standard for the performance testing of PEMEEs, making it suitable for large-scale application. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of a method for evaluating a proton exchange membrane electrode for water electrolysis according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of a proton exchange membrane electrode in one embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the electrolytic cell assembly in one embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of an electrolytic cell leak test in one embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of a proton exchange membrane electrode evaluation system for water electrolysis in one embodiment of the present invention.

[0021] Label Explanation: 11. Electrolytic cell; 101. Anode end plate; 102. Anode power collection plate; 103. Anode flow field plate; 104. Anode sealing gasket; 105. Anode diffusion layer; 106. Cathode diffusion layer; 107. Cathode sealing gasket; 108. Cathode flow field plate; 109. Cathode power collection plate; 110. Cathode end plate; 12. Proton exchange membrane electrode; 120. Proton exchange membrane; 121. Cathode catalyst layer; 122. Anode catalyst layer; 13. Flow meter; 14. First switch; 15. Second switch; 16. Third switch; 17. Fourth switch; 18. Fifth switch; 19. Testing unit; 20. Performance test data reading unit; 21. Data processing unit; 22. Evaluation unit. Detailed Implementation

[0022] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] In the description of this invention, it should be understood that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Please see Figure 1 As shown, in one embodiment of the present invention, the evaluation method of a proton exchange membrane electrode for water electrolysis provided by the present invention includes, for example, steps S11-S14.

[0028] Step S11: Provide multiple proton exchange membrane electrodes.

[0029] Step S12: Perform different performance tests on the proton exchange membrane electrode to obtain multiple performance test data.

[0030] Step S13: Process the performance test data to obtain multiple performance index data.

[0031] Step S14: Evaluate the overall performance of the proton exchange membrane electrode based on multiple performance index data.

[0032] Please see Figures 1 to 2As shown, in one embodiment of the present invention, in step S11, a plurality of proton exchange membrane electrodes are provided. The proton exchange membrane electrode 12 includes a proton exchange membrane 120, a cathode catalyst layer 121, and an anode catalyst layer 122, etc. The proton exchange membrane 120 includes a first surface and a second surface disposed opposite to each other. The cathode catalyst layer 121 is disposed on the first surface, and the anode catalyst layer 122 is disposed on the second surface. In this embodiment, the materials of the cathode catalyst layer 121 and the anode catalyst layer 122 include, for example, noble metals. In other embodiments of the present invention, in addition to noble metals, the cathode catalyst layer 121 and the anode catalyst layer 122 may also include alloy metals. The present invention does not limit the types of noble metals and alloy metals. For example, taking platinum (Pt) and iridium (Ir) as noble metals, and M as an alloy metal, M is, for example, one of the transition metals such as manganese, chromium, iron, cobalt, nickel, copper, zinc, molybdenum, and tungsten. The evaluation method will be described.

[0033] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, different performance tests are performed on the proton exchange membrane electrode to obtain multiple performance test data. Then, the performance test data are processed to obtain multiple performance index data. The environmental conditions for performance testing are clean, well-ventilated, with an ambient temperature of, for example, 20℃-30℃ and a relative humidity of, for example, not exceeding 75%. The quality of the raw water used in the performance test should meet the requirements of Table 1, the quality of the circulating cooling water used in the performance test should meet the requirements of Table 2, and the detectors, instruments, and other equipment used in the performance test should meet the accuracy requirements of Table 3. Furthermore, the calibration or verification reports of the detectors, instruments, etc., used should be within their validity period. Performance tests include, for example, precious metal loading tests, thickness tests, hydrogen permeability tests, ohmic resistance tests, electrochemical active area tests, polarization curve tests, and chemical stability tests.

[0034] Table 1 Requirements for feed water in proton exchange membrane electrode performance testing

[0035] Table 2 Requirements for circulating cooling water in proton exchange membrane electrode performance testing

[0036] Table 3. Accuracy Requirements for Instruments and Meters for Testing Proton Exchange Membrane Electrode Performance

[0037] Please see Figure 1As shown, in one embodiment of the present invention, in steps S12-S13, the noble metal loading test includes, for example, inductively coupled plasma (ICP) spectroscopy and X-ray fluorescence spectroscopy (XRF). In the ICP method, noble metal loading test data is obtained through steps such as sample preparation, sample drying, sample oxidative ashing, sample nitration, sample dissolution, test sample preparation, standard curve plotting, and concentration analysis. The noble metal loading test data is then processed to obtain noble metal loading index data. Specifically, in sample preparation, the proton exchange membrane electrode is first cut to obtain the test sample, and the area of ​​the test sample is, for example, greater than or equal to 20 cm². 2 Furthermore, the test sample should be clean, with neat edges, and free from chemical oxidation or electrochemical corrosion.

[0038] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining the test sample, the test sample is placed in an oven for drying at a temperature of, for example, 78℃-82℃, for a drying time of, for example, 1h-7h. After drying, the length and width of the test sample are accurately measured with calipers, and then the test sample is cut into pieces and placed in a crucible. The test sample in the crucible is then oxidized and ashed. Specifically, the crucible containing the test sample is placed in a container, and the container is heated to a first temperature in an air atmosphere and held for a first time to oxidize and carbonize the test sample. Then, the container is heated to a second temperature and held for a second time to oxidize and ashed the test sample. Finally, the test sample is cooled to room temperature. The container is, for example, a muffle furnace, and the crucible is, for example, a covered corundum crucible. The first temperature is, for example, 400℃-500℃, and the first time is, for example, 3h-9h. The second temperature is, for example, 900℃-950℃, and the second time is, for example, 10h-14h.

[0039] Please see Figure 1 As shown, in one embodiment of the present invention, after the test sample is oxidized and ashed, the test sample is moistened with a first reagent, and a mixed solution is added to the test sample along the crucible wall. Then, the mixed solution is heated to a third temperature to nitrate the test sample. When the volume of the mixed solution is concentrated to half, a second reagent is added, and the mixed solution and the second reagent are heated to the third temperature again. This cycle is repeated until the solution in the crucible is nearly transparent and free of suspended matter. The first reagent is, for example, double-distilled water, with a conductivity greater than or equal to 18.2 MΩ·cm. The mixed solution is, for example, a mixture of concentrated sulfuric acid and concentrated nitric acid, with a mass fraction of concentrated sulfuric acid of 90%-99% and a mass fraction of concentrated nitric acid of 60%-75%, and a volume ratio of concentrated sulfuric acid to concentrated nitric acid of 1:(2-4). The third temperature is, for example, 50℃-100℃. The amount of the second reagent added is, for example, 0.2 mL-0.6 mL, and the second reagent is, for example, hydrogen peroxide, with a mass fraction of 20%-40%.

[0040] Please see Figure 1 As shown, in one embodiment of the present invention, after the test sample is nitrated, aqua regia is added to the test sample along the crucible wall. The test sample and aqua regia are then heated to a fourth temperature until the test sample is completely dissolved, resulting in a clear and transparent sample solution. The fourth temperature is, for example, 70°C-90°C. The mass fraction of concentrated hydrochloric acid used to prepare the aqua regia is, for example, 20%-40%, and the mass fraction of concentrated nitric acid is, for example, 60%-75%. Next, the test sample is prepared using the sample solution. Specifically, the sample solution is completely transferred to a volumetric flask, and the initial volume of the test sample is made up to the required concentration with double-distilled water. During testing, an appropriate amount of this solution is diluted to the required concentration according to a preset ratio to obtain the ICP analysis solution.

[0041] Please see Figure 1 As shown, in one embodiment of the present invention, after the test sample is prepared, the standard solutions of Pt, Ir, and M are analyzed by spectral analysis using an ICP device to plot standard curves for Pt, Ir, and M. After obtaining the standard curves, the concentrations of Pt, Ir, and M in the test sample are analyzed by spectral analysis using an ICP device, and the concentrations of Pt, Ir, and M in the test sample are obtained based on the standard curves. The minimum detection limit of the ICP device is, for example, less than or equal to 1 μg / L.

[0042] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining the concentration data of Pt, Ir, and M in the test sample, the Pt loading, Ir loading, and M loading in the proton exchange membrane electrode are calculated to obtain metal loading index data. Based on this, the noble metal loading performance of the proton exchange membrane electrode is evaluated. The specific calculation formula is as follows: L Pt / Ir =n×C Pt / Ir ×V Pt / Ir / S MEA ; L M =n×C M ×V Pt / Ir / S MEA ; Among them, L Pt / Ir The Pt / Ir loading in the proton exchange membrane electrode is expressed in milligrams per square centimeter (mg / cm²). 2 ), where n is the dilution factor for preparing the test sample into an ICP analysis solution, and C Pt / Ir The Pt / Ir concentration in the ICP test solution is expressed in milligrams per liter (mg / L), V Pt / Ir The initial volume of the prepared test sample, in liters (L), S MEA The effective area of ​​the proton exchange membrane electrode is expressed in square centimeters (cm²).2 ), L M The loading of M in the proton exchange membrane electrode is expressed in milligrams per square centimeter (mg / cm²). 2 ), C M The concentration of metal M in the ICP test solution is expressed in milligrams per liter (mg / L).

[0043] Please see Figure 1 As shown, in one embodiment of the present invention, in the XRF method, for example through sample preparation and sample testing, test data on the noble metal loading at different test points on the proton exchange membrane electrode are obtained. Then, the noble metal loading test data are processed to obtain index data such as the difference between the maximum and minimum noble metal loading values ​​of the proton exchange membrane electrode, and the relative deviation of the noble metal loading. These are used as a basis to evaluate the uniformity of the noble metal loading of the proton exchange membrane electrode. Specifically, during sample preparation, the proton exchange membrane electrode is first cut to obtain a test sample, the area of ​​which is, for example, greater than or equal to 25 cm². 2 The test sample should be square or otherwise free of wrinkles, defects and damage, and should be a proton exchange membrane electrode with only a cathode catalyst layer or an anode catalyst layer.

[0044] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining the test sample, the test sample is placed on a first plate, and then a second plate is placed on the other surface of the test sample. Then, using an XRF instrument, the precious metal loading at multiple test points on the test sample is measured through the first or second plate to obtain multiple precious metal loading test data. The materials of the first and second plates are, for example, selected from polytetrafluoroethylene or other organic materials that do not contain metal elements. There are, for example, at least nine test points, which should be evenly distributed on the test sample, and the distance between each test point and the edge of the test sample should be, for example, greater than 5 mm.

[0045] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining the precious metal loading test data, the difference between the maximum and minimum precious metal loading values, the average precious metal loading, and the relative deviation of the precious metal loading are calculated to evaluate the uniformity of the precious metal loading in the test sample. The calculation formula is as follows: D=D max -D min ; ; S=(D i -D) / D×100%; Where D represents the average loading of noble metals in the proton exchange membrane electrode, expressed in milligrams per square centimeter (mg / cm²). 2 ), Di This is a measurement of the noble metal loading at a specific test point on a proton exchange membrane electrode, expressed in milligrams per square centimeter (mg / cm²). 2 (n is the number of test points, and S is the relative deviation of the noble metal loading of the proton exchange membrane electrode.) D is the difference between the maximum and minimum precious metal loading, expressed in milligrams per square centimeter (mg / cm²). 2 ), D max This represents the maximum precious metal loading capacity, expressed in milligrams per square centimeter (mg / cm²). 2 ), D min This is the minimum precious metal loading, expressed in milligrams per square centimeter (mg / cm²). 2 ).

[0046] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, the thickness test, for example, involves sample preparation and sample testing, measuring the thickness of the proton exchange membrane electrode at different test points to obtain multiple thickness test data. Then, the thickness test data is processed to obtain index data such as the difference between the maximum and minimum thicknesses of the proton exchange membrane electrode and the relative thickness deviation. Based on this, the thickness uniformity of the proton exchange membrane electrode is evaluated. Specifically, during sample preparation, the proton exchange membrane electrode is first cut to obtain a test sample. The area of ​​the test sample is, for example, greater than or equal to 25 cm². 2 The test sample should be square or otherwise free of wrinkles, defects and damage, and should be a proton exchange membrane electrode with only a cathode catalyst layer or an anode catalyst layer.

[0047] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining the test sample, the test sample is placed under preset temperature and preset relative humidity conditions for a preset time. The preset temperature is, for example, 23℃-27℃, the preset relative humidity is, for example, 45%-55%, and the preset time is, for example, 0.5h-1.5h. Next, after calibrating the zero point of the thickness gauge, the thickness of different test points on the test sample is measured using the thickness gauge to obtain multiple thickness test data. During thickness measurement, wrinkles and damage to the test sample should be avoided. The accuracy of the thickness gauge is, for example, greater than or equal to 0.001mm, and the pressure applied by the test head of the thickness gauge to the surface of the test sample is, for example, 3N / cm². 2 -7N / cm 2 The number of test points should be at least nine, and the test points should be evenly distributed on the test sample, with the test points being at least 5 mm away from the edge of the test sample.

[0048] Please see Figure 1As shown, in one embodiment of the present invention, after obtaining the thickness test data, the difference between the maximum and minimum thickness values, the average thickness, and the relative deviation of the thickness are calculated to evaluate the uniformity of the test sample thickness. The calculation formula is as follows: d=d max -d min ; ; s=(d i -d) / d×100%; Where d is the average thickness of the proton exchange membrane electrode, in micrometers (μm). i —Thickness measurement of a proton exchange membrane electrode at a specific test point, in micrometers (μm), where n is the number of test points and s is the relative deviation of the proton exchange membrane electrode thickness. d is the difference between the maximum and minimum thickness, expressed in micrometers (μm). max The maximum value of the thickness is expressed in micrometers (μm), d min This represents the minimum thickness, expressed in micrometers (μm).

[0049] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, the hydrogen permeability test is performed, for example, through sample preparation and sample testing, to obtain hydrogen permeability test data of the proton exchange membrane electrode. Then, the hydrogen permeability test data is processed to obtain the hydrogen permeability Q. g and hydrogen permeability coefficient P g Based on these indicators, the hydrogen permeability performance of the proton exchange membrane electrode is evaluated. Specifically, during sample preparation, the proton exchange membrane electrode is first cut to obtain a test sample, such as a circular sample. The diameter of the test sample depends on the equipment used in subsequent testing, and the test sample should be free of wrinkles or visible defects.

[0050] Please see Figure 1As shown, in one embodiment of the present invention, after obtaining the test sample, the test sample is dried at a drying temperature, for example, 70°C-90°C, for at least 4 hours. Next, the hydrogen permeability of the test sample is tested, for example, using a differential pressure gas permeameter, a vacuum pump, and a water bath circulation temperature control device. Specifically, when testing the hydrogen permeability, the high-pressure chamber and low-pressure chamber of the differential pressure gas permeameter are separated. Vacuum oil is evenly applied to the area outside the test mark line on the low-pressure chamber test bench. A medium-speed qualitative filter paper is placed directly above the central cavity on the low-pressure chamber test bench. The test sample is then flatly attached to the oil-coated low-pressure chamber test bench, ensuring that no air bubbles are generated in the contact area between the test sample and the oil. Next, the high-pressure chamber and low-pressure chamber are tightly closed, and the water bath circulation is started. The temperature control device is set to a temperature, for example, 20°C-25°C. Turn on the power switch of the gas permeator, open the instrument's computer operating software, and run the safety gas replacement process. The safety gas can be, for example, nitrogen or an inert gas, and the replacement time should be, for example, greater than or equal to 600 seconds. After the safety gas replacement is complete, switch the valve to introduce hydrogen gas, and simultaneously turn on the vacuum pump. Both the high-pressure and low-pressure chambers are simultaneously evacuated and degassed to below 10 Pa. Then close the isolation valve, open the test gas cylinder and gas source switch to fill the high-pressure chamber with test gas. The gas stress in the high-pressure chamber should be, for example, (1-1.1)×10⁻⁶. 5 If the gas pressure in the high-pressure chamber is too high, the isolation valve should be opened to release it. The test gas can be, for example, hydrogen. After degassing, the instrument automatically closes the exhaust valves of both the high-pressure and low-pressure chambers and begins the permeability test. Exclude the nonlinear permeation phase at the beginning of the test and record the pressure change in the low-pressure chamber. P and test time t. Continue the test until the same time interval is reached. The pressure change in the low-pressure chamber within time t remains constant, achieving stable transmission. At least three consecutive time intervals should be considered. pressure change value t P, and then perform data processing on it.

[0051] Please see Figure 1 As shown, in one embodiment of the present invention, the pressure change value is obtained. After P, the data is processed to obtain the hydrogen permeability Q of the proton exchange membrane electrode. g and hydrogen permeability coefficient P g This is used to evaluate the hydrogen permeability of the proton exchange membrane electrode. Specifically, the hydrogen permeability Q... g and hydrogen permeability coefficient P g The calculation formula is as follows: ; ; Among them, Q gHydrogen permeability, expressed in cubic centimeters per square meter (tPa). 3 / (m 2 ·d·Pa)], The value of V represents the arithmetic mean of the gas pressure change in the low-pressure chamber per unit time during stable transmission, expressed in Pascals per hour (Pa / h). V is the volume of the low-pressure chamber, expressed in cubic centimeters (cm³). 3 S represents the permeation area of ​​the test sample, in square meters (m²). 2 T represents the test temperature in Kelvin (K), P1-P2 represents the pressure difference across the test sample in Pascals (Pa), and T0 and P0 represent the temperature (273.15 K) and pressure (1.013 × 10⁻⁶ K) under standard conditions. 5 Pa), P g Hydrogen permeability coefficient, measured in cubic centimeters per square centimeter per second per pascal (cm²). 3 ·cm / (cm 2 ·s·Pa)], where d is the average thickness of the test sample in centimeters (cm).

[0052] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, the ohmic resistance test is performed on the proton exchange membrane electrode, for example, using a multimeter. Specifically, the multimeter is adjusted to its range and zeroed with ohms. The two probes of the multimeter are short-circuited so that the scale reads zero, ensuring accurate measurement. After zeroing, the two probes of the multimeter are connected to any two points on the proton exchange membrane electrode, and the reading indicated by the pointer is taken as the resistance value. Multiple measurements are taken, and the average value is obtained to obtain the average resistance value. This average resistance value is used to evaluate the ohmic resistance test performance of the proton exchange membrane electrode. The number of measurements is, for example, at least three.

[0053] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, the electrochemical active area test is performed, for example, by an electrochemical potentiostat. Specifically, the electrochemical active area test is performed, for example, by steps such as electrolytic cell assembly, electrolytic cell leak testing, test platform installation, electrode activation, and electrode testing, to obtain a cyclic voltammetry (CV) curve of the proton exchange membrane electrode. Then, the CV curve is processed to calculate the electrochemical active area, and based on this, the electrochemical active area test performance of the proton exchange membrane electrode is evaluated.

[0054] Please see Figure 1 and Figure 3As shown, in one embodiment of the present invention, during the assembly of the electrolytic cell 11, the anode end plate 101, anode sampling plate 102, anode flow field plate 103, anode sealing gasket 104, anode diffusion layer 105, proton exchange membrane electrode 12, cathode diffusion layer 106, cathode sealing gasket 107, cathode flow field plate 108, cathode sampling plate 109, and cathode end plate 110 are assembled in sequence according to the positions of the positioning holes. Then, tools such as bolts, nuts, and torque wrenches are used to tighten the electrolytic cell 11 according to the assembly requirements. When tightening the electrolytic cell 11, attention should be paid to diagonal tightening. After tightening, the thickness of the entire electrolytic cell 11, anode sealing gasket 104, anode diffusion layer 105, proton exchange membrane electrode 12, cathode diffusion layer 106, and cathode sealing gasket 107 is measured, and the compression ratio is calculated.

[0055] Please see Figure 1 , Figure 3 and Figure 4 As shown, in one embodiment of the present invention, after the electrolytic cell 11 is assembled, an electrolytic cell leak testing device is assembled to test the electrolytic cell 11 for leaks. The electrolytic cell leak testing device includes, for example, the electrolytic cell 11, a mass flow meter 13, a gas source, at least five switches, and connecting pipes, with the connecting pipes connecting adjacent components. In this embodiment, the flow meter 13 is, for example, a mass flow meter, and there are, for example, five switches: a first switch 14, a second switch 15, a third switch 16, a fourth switch 17, and a fifth switch 18. The second switch 15 is connected to the anode outlet of the electrolytic cell 11 via a connecting pipe. The third switch 16 is connected to the anode inlet of the electrolytic cell 11 via another connecting pipe, and the second switch 15 and the third switch 16 are connected in parallel to the flow meter 13. The first switch 14 is connected to the side of the flow meter 13 away from the third switch 16 and the second switch 15, and the side of the first switch 14 away from the flow meter 13 is connected to a gas source. The fourth switch 17 is connected to the cathode inlet of the electrolytic cell 11 via a connecting pipe, and the fifth switch 18 is connected to the cathode outlet of the electrolytic cell 11 via another connecting pipe. The side of the fourth switch 17 away from the cathode inlet and the side of the fifth switch 18 away from the cathode outlet are both connected to the atmosphere. After the electrolytic cell leak testing device is assembled, the electrolytic cell 11 is tested for leaks, including, for example, external leakage measurement and internal leakage measurement. For external leakage measurement, turn on the first switch 14 and the second switch 15, and turn off the third switch 16, the fourth switch 17 and the fifth switch 18. Read the reading of the flow meter 13 and record the value. For internal leakage measurement, turn on the first switch 14, the second switch 15 and the fifth switch 18, and turn off the third switch 16 and the fourth switch 17. Read the reading of the flow meter 13 and record the value.

[0056] Please see Figure 1As shown, in one embodiment of the present invention, after the leak test is completed, the interface between the electrolytic cell and the test platform is connected to install the test platform. Specifically, the interface connecting the electrolytic cell and the test platform includes, for example, pipe connections and electrical wire connections. When connecting the pipes, at the anode of the electrolytic cell, the inlet of the electrolytic cell is connected to the outlet of the test platform, and the outlet of the electrolytic cell is connected to the inlet of the test platform, for example, using a bottom-in, top-out principle. At the cathode of the electrolytic cell, the cathode generally has two interfaces, which can be connected using either of two methods. The first method is to seal one interface and connect the other side to the cathode interface of the test platform. The second method is to connect both interfaces to the cathode inlet and outlet of the test platform respectively, connecting the lower interface to the water interface of the test platform and the upper interface to the air outlet of the test platform. When connecting the pipes, attention should be paid to the insulation of the inlet and outlet water channels.

[0057] Please see Figure 1 As shown, in one embodiment of the present invention, after the pipeline connection is completed, the wire interface is connected. Specifically, the positive electrode of the test platform is connected to the cathode of the electrolytic cell, and the negative electrode of the test platform is connected to the cathode of the electrolytic cell. During the test connection, the voltage acquisition lines of the main positive and negative electrodes are connected together with the electrodes.

[0058] Please see Figure 1 As shown, in one embodiment of the present invention, after the test platform is installed, it is started, and initial parameters are set, including, for example, water flow rate, temperature, and electrolytic cell parameters, to preheat the electrolytic cell. After preheating, a constant current mode is selected, starting from 0.1 A / cm². 2 Begin gradually applying current, ensuring the individual cell voltage remains below 2.1V during each application. When the current reaches 2A / cm², [further steps are taken]. 2 At 2A / cm 2 The proton exchange membrane electrode was activated under the specified conditions, and the monomer voltage was observed and recorded every 5 minutes until activation was complete. Activation was considered complete when the electrode voltage fluctuated within 2mV (inclusive) for 10 minutes under constant current mode.

[0059] Please see Figure 1 As shown, in one embodiment of the present invention, after electrode activity is completed, the working electrode is purged with high-purity nitrogen gas, and the electrolytic cell is connected to an electrochemical potentiostat. Deionized water is introduced into the anode at a flow rate of 10 L / min, and nitrogen gas is introduced into the cathode at a flow rate of 10 mL / min. The electrolytic cell is scanned using the CV method, and the CV curve is recorded after it stabilizes. The CV scan range is, for example, 0-2 V, and the scan speed is, for example, 10-30 mV / s.

[0060] Please see Figure 1As shown, after obtaining the CV curve, the CV curve is processed, and the electrochemical active area S is calculated. ECA Based on this, the electrochemical activity of the proton exchange membrane electrode was evaluated. ECA The calculation formula is as follows: S ECA =0.1×S H / (Q r ×v×M Pt ); Among them, S ECA The electrochemical active area of ​​Pt in the proton exchange membrane electrode is expressed in square meters per gram (m²). 2 / g), S H Q represents the peak area of ​​hydrogen oxidation-desorption on the cyclic voltammetry curve, in Ampere-volts (A·V). r The adsorption charge constant for hydroxide on a smooth Pt surface is 0.21 millicoulombs per square centimeter (0.21 mC / cm²). 2 ), v is the cyclic voltammetric scan rate, in volts per second (V / s), M Pt The mass of Pt in the proton exchange membrane electrode is expressed in grams (g).

[0061] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, the polarization curve test involves steps such as sample preparation, electrolyzer assembly, electrolyzer leak testing, test platform installation, electrode activation, and polarization performance testing. The performance data of the electrolyzer under different currents are measured. Performance data includes, for example, anode water flow rate, voltage, outlet temperature, hydrogen inlet pressure, and hydrogen production. Based on this performance data, a polarization curve is obtained, and this curve is used to evaluate the polarization performance of the proton exchange membrane electrode. Specifically, during sample preparation, the proton exchange membrane electrode is first cut to obtain a test sample. The area of ​​the test sample is, for example, greater than or equal to 25 cm². 2 The test samples should be free of oil stains, wrinkles, defects, and damage, and should meet the test requirements for retesting. After obtaining the test samples, the electrolytic cell assembly, electrolytic cell leak testing, test platform installation, and electrode activation are performed in sequence. The specific steps are the same as those for electrolytic cell assembly, electrolytic cell leak testing, test platform installation, and electrode activation in the electrochemical active area test, and will not be elaborated further here.

[0062] Please see Figure 1As shown, in one embodiment of the present invention, after electrode activation, a constant current mode is adopted, and a preset current is applied to the electrolytic cell. The anode water flow rate, voltage, outlet temperature, hydrogen inlet pressure, and hydrogen production under the preset current are measured, and the current density under the preset current, i.e., the ratio of current to test sample area, is calculated. The measurement data and calculation data are recorded. Then, the preset current is changed, and the above operation is repeated. In this embodiment, the preset current is, for example, 0-50A, and the change value of the preset current is, for example, the same each time, for example, 3-7A. The preset current is changed sequentially, for example, 0, 5A, 10A, 15A, 20A, 25A, 30A, 35A, 40A, 45A, and 50A.

[0063] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining multiple voltage data under different preset currents or current densities, a polarization curve is plotted based on the voltage and preset current, or voltage and current density, and the polarization performance of the proton exchange membrane electrode is evaluated based on this curve.

[0064] Please see Figure 1 As shown, in one embodiment of the present invention, in steps S12-S13, the chemical stability test involves steps such as sample preparation, electrolytic cell assembly, electrolytic cell leak testing, test platform installation, electrode activation, and stability testing. The voltage of the electrolytic cell is measured at different times, and the decay rate is calculated. Based on this, the chemical stability of the proton exchange membrane electrode is evaluated. Specifically, during sample preparation, the proton exchange membrane electrode is first cut to obtain a test sample. The area of ​​the test sample is, for example, greater than or equal to 25 cm². 2 The test samples should be free of oil stains, wrinkles, defects, and damage, and should meet the test requirements for retesting. After obtaining the test samples, the electrolytic cell assembly, electrolytic cell leak testing, test platform installation, and electrode activation are performed in sequence. The specific steps are the same as those for electrolytic cell assembly, electrolytic cell leak testing, test platform installation, and electrode activation in the electrochemical active area test, and will not be elaborated further here.

[0065] Please see Figure 1 As shown, in one embodiment of the present invention, after the electrode is activated, the electrolytic cell is loaded to a preset current density, and the initial voltage is recorded. Then, the voltage of the electrolytic cell is recorded at preset time intervals during the operating time. The operating time is, for example, 150h-200h, or 168h, and the preset time interval is, for example, 0.5h-2h, or 1h. After obtaining the voltage at different times, the decay rate of the voltage at different times is calculated, and the chemical stability of the proton exchange membrane electrode is evaluated based on the decay rate.

[0066] Please see Figure 1As shown, in one embodiment of the present invention, in steps S12-S13, multiple performance test data are obtained by performing noble metal loading, thickness testing, hydrogen permeability testing, ohmic resistance testing, electrochemical active area testing, polarization curve testing, and chemical stability testing on the proton exchange membrane electrode. Then, the performance test data are processed to obtain multiple performance index data, such as the noble metal loading L. Pt / Ir The difference between the maximum and minimum values ​​of precious metal carrying capacity D or the relative deviation of the precious metal load, S, the difference between the maximum and minimum thickness. d or relative deviation of thickness s, hydrogen permeability Q g or hydrogen permeability coefficient P g Average resistance value, electrochemical active area S ECA Based on parameters such as polarization curves and voltage decay rates, the noble metal loading, uniformity of noble metal loading, thickness uniformity, hydrogen permeability, ohmic resistance, electrochemical active area, polarization performance, and chemical stability of proton exchange membrane electrodes are evaluated. This invention provides a unified, comprehensive, and objective industry standard for testing various performance characteristics of proton exchange membrane electrodes by defining the testing details, including instruments, conditions, and procedures, thus filling a gap in industry standards for proton exchange membrane electrode performance testing.

[0067] Please see Figure 1 As shown, in one embodiment of the present invention, after obtaining multiple performance index data, in step S14, the comprehensive performance of the proton exchange membrane electrode is evaluated based on the multiple performance index data. In this embodiment, taking the application of the proton exchange membrane electrode in the water electrolysis industry as an example, an evaluation standard for the proton exchange membrane electrode is provided. Specific evaluation standards are shown in Table 4.

[0068] Table 4 Evaluation criteria for proton exchange membrane electrodes in the water electrolysis industry

[0069] Please refer to Table 4. In one embodiment of the present invention, multiple performance index data are obtained by testing the noble metal loading, thickness, hydrogen permeability, ohmic resistance, electrochemical active area, polarization curve, and chemical stability of the proton exchange membrane electrode. These data are then compared with the evaluation criteria to comprehensively evaluate whether the proton exchange membrane is suitable for use in water electrolysis technology, thereby providing a reliable reference for the selection of proton exchange membrane electrodes for water electrolysis.

[0070] Please see Figure 5As shown, the present invention also provides an evaluation system for a proton exchange membrane electrode for water electrolysis, which is used in the aforementioned evaluation method for the proton exchange membrane electrode. The evaluation system includes a testing unit 19, a performance test data reading unit 20, a data processing unit 21, and an evaluation unit 22. The proton exchange membrane electrode is placed in the testing unit 19 to test its performance. The performance test data reading unit 20 is electrically connected to the testing unit 19 to obtain performance test data of the proton exchange membrane electrode under different test conditions. The data processing unit 21 is electrically connected to the performance test data reading unit 20 to process the obtained performance test data to obtain performance index data. The evaluation unit 22 is electrically connected to the data processing unit 21 to perform a comprehensive evaluation of the performance index data.

[0071] In summary, this invention proposes an evaluation method and system for proton exchange membrane electrodes used in water electrolysis. By specifying details such as the conditions and procedures for precious metal loading testing, thickness testing, hydrogen permeability testing, ohmic resistance testing, electrochemical active area testing, polarization curve testing, and chemical stability testing, it provides a unified, comprehensive, and objective industry standard for testing various performance characteristics of proton exchange membrane electrodes, making it suitable for large-scale application in the water electrolysis industry. Furthermore, the evaluation method provided by this invention can comprehensively evaluate the performance of proton exchange membrane electrodes, offering a reliable reference for the selection of proton exchange membrane electrodes for water electrolysis.

[0072] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for evaluating a proton exchange membrane electrode for electrolysis of water, characterized by, At least comprising the following steps: Providing a plurality of proton exchange membrane electrodes; Performing different performance tests on the proton exchange membrane electrodes to obtain a plurality of performance test data; Processing the performance test data to obtain a plurality of performance index data; And Based on the plurality of performance index data, evaluating the comprehensive performance of the proton exchange membrane.

2. The evaluation method according to claim 1, characterized by The performance tests include noble metal loading tests, thickness tests, hydrogen permeation rate tests, ohmic resistance tests, electrochemical active area tests, polarization curve tests, and chemical stability tests.

3. The evaluation method according to claim 2, characterized by, The noble metal loading test calculates the noble metal loading data by measuring the concentration of noble metal in the proton exchange membrane electrode.

4. The evaluation method according to claim 3, characterized by The calculation formula of the noble metal loading data is as follows: L Pt / Ir =n×C Pt / Ir ×V Pt / Ir / S MEA ; wherein L Pt / Ir is the loading of noble metal in the proton exchange membrane electrode, in milligrams per square centimeter (mg / cm 2 ), n is the dilution factor to prepare the test sample into a solution for ICP analysis, C Pt / Ir is the concentration of noble metal in the ICP test solution, in milligrams per liter (mg / L), V Pt / Ir is the initial volume of the test sample prepared, in liters (L), S MEA is the effective area of the proton exchange membrane electrode, in square centimeters (cm 2 ).

5. The evaluation method according to claim 2, characterized by The noble metal loading test obtains the relative deviation of noble metal loading by measuring the noble metal loading of a plurality of test points on the proton exchange membrane electrode to evaluate the uniformity of noble metal loading on the proton exchange membrane electrode.

6. The evaluation method according to claim 2, characterized by Before performing the electrochemical active area test, the polarization curve test, or the chemical stability test, at least comprising the following steps: Installing the proton exchange membrane electrode in an electrolytic cell to complete the assembly of the electrolytic cell; Leak testing the electrolytic cell; Connecting the electrolytic cell to a test bench; and Activating the proton exchange membrane electrode.

7. The evaluation method according to claim 6, characterized by The electrochemical active area test obtains a cyclic voltammogram by scanning the electrolytic cell using cyclic voltammetry, applying a voltage to the proton exchange membrane electrode, and processing the data to calculate the electrochemical active area. The calculation formula of the electrochemical active area is as follows: S ECA =0.1×S H / (Q r ×v×M Pt ); where S ECA is the electrochemically active area of platinum in the proton exchange membrane electrode, in square meters per gram (m 2 / g), S H is the oxidation desorption peak area of hydrogen on the cyclic voltammetry curve, in ampere-volt (A·V), Q r is the hydrogen oxidation adsorption charge constant of the smooth Pt surface, 0.21 milliloule per square centimeter (0.21 mC / cm 2 ), v is the cyclic voltammetry scanning rate, in volts per second (V / s), M Pt is the mass of Pt in the proton exchange membrane electrode, in grams (g).

8. The evaluation method according to claim 6, characterized by The polarization curve test measures the current, voltage, outlet temperature, hydrogen pressure, and hydrogen production of the electrolytic cell by applying a constant current to the electrolytic cell to obtain polarization performance test data.

9. The evaluation method according to claim 6, characterized by, The chemical stability test obtains chemical stability test data by loading the proton exchange membrane electrode to a predetermined current density, regularly recording the voltage of the electrolytic cell, and calculating the voltage decay rate to obtain chemical stability index data.

10. An evaluation system of a proton exchange membrane electrode for electrolysis of water, characterized by, At least comprising: A test unit for testing the performance of the proton exchange membrane electrode; A performance test data reading unit electrically connected to the test unit for obtaining performance test data of the proton exchange membrane electrode in different tests; A data processing unit electrically connected to the performance test data reading unit for processing the performance test data to obtain performance index data; And An evaluation unit electrically connected to the data processing unit for comprehensive evaluation of the performance index data.

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