A durability testing method for anion exchange membrane electrolyzer

Abstract

The present invention relates to the field of durability testing of anion exchange membrane electrolyzers, and specifically to a durability testing method for anion exchange membrane electrolyzers. A durability testing method for anion exchange membrane electrolyzers, comprising the following testing steps: S1, electrolyzer assembly; S2, activation and initial testing; S3, accelerated durability testing (a) operation at rated current density for 100 hours; (b) operation at high current density for 100 hours; (c) periodic alternation of rated current density and high current density for 100 hours; S4, post-test evaluation. The present application simulates load fluctuations in actual applications through dynamic operating conditions, and combined with the accelerated conditions of high current density, can induce a degradation process similar to long-term steady-state operation within 300 hours. Through the scientific design of the test process, this method shortens the traditional steady-state test cycle of several months or even one year to several weeks, while ensuring the consistency of the test results with the actual operating conditions.

Description

Technical Field

[0001] The invention relates to the field of durability testing of anion exchange membrane electrolyzers, and in particular to a durability testing method of anion exchange membrane electrolyzers. Background Art

[0002] Low-temperature water electrolysis includes three technologies: alkaline water electrolysis, proton exchange membrane water electrolysis, and anion exchange membrane water electrolysis. AEM water electrolysis, as the latest generation technology, not only retains the advantages of PEM water electrolysis using solid polymer electrolytes and a zero-gap structure, but its alkaline environment allows the use of inexpensive metal catalysts and plate materials, achieving both low cost and high efficiency.

[0003] In view of the above prior art, the inventors found that the stability test of the existing AEM electrolyzer is usually carried out in a steady-state mode, for example, at 1A / cm 2 Evaluating the life of an AEM electrolyzer under steady-state operation presents two challenges. First, stability testing under dynamic conditions can more realistically reflect the degradation process of an AEM electrolyzer under actual operating conditions, particularly when it is periodically started and stopped or coupled with intermittent, unpredictable renewable electricity. Second, evaluating the life of an AEM electrolyzer under steady-state conditions typically takes a long time, typically several months or even more than a year. Given that the service life of an AEM electrolyzer can be up to several years, it is essential to be able to obtain electrolyzer degradation results in a relatively short period of time during the development or improvement of materials such as catalysts, ionomers, membranes, and membrane electrodes. Summary of the Invention

[0004] Based on the technical problems existing in the above-mentioned prior art, the present invention provides a durability testing method for an anion exchange membrane electrolyzer.

[0005] A durability testing method for an anion exchange membrane electrolyzer comprises the following testing steps:

[0006] S1. Electrolyzer assembly: Cathode material, anode material and gas diffusion layer are assembled into membrane electrode, and then assembled with flow channel plate, collector plate and sealing gasket into an anion exchange membrane electrolyzer;

[0007] S2. Activation and initial testing: The electrolytic cell was operated at a constant current density for activation, followed by polarization curve and electrochemical impedance spectroscopy testing.

[0008] S3, Accelerated Endurance Test: Conduct the following three phases of testing in sequence:

[0009] (a) Operation at rated current density for 100 h;

[0010] (b) Operation at high current density for 100 h;

[0011] (c) Rated current density and high current density are periodically alternating for 100 h;

[0012] S4. Post-test evaluation: Retest the polarization curve and electrochemical impedance spectrum, calculate the attenuation rate of the electrolyzer and predict its service life, and the durability test of the anion exchange membrane electrolyzer is completed.

[0013] Through the above technical solution, this application realizes efficient evaluation of the life of the electrolyzer through a closed-loop process of "assembly-activation-three-stage accelerated testing-evaluation". Among them, the assembly stage uses cathode, anode and gas diffusion layer to ensure the catalytic activity and structural stability of the membrane electrode; the activation stage uses constant current operation to make the electrolyzer enter a stable state, providing a reliable benchmark for subsequent tests; the three-stage accelerated test simulates the load fluctuations in actual applications through dynamic working conditions, combined with the acceleration conditions of high current density, and can induce a degradation process similar to long-term steady-state operation within 300 hours. This method shortens the traditional steady-state test cycle of several months or even a year to a few weeks, while ensuring the consistency of the test results with the actual working conditions, providing an efficient and reliable evaluation tool for new material development and process optimization.

[0014] Furthermore, the cathode material is made using the following technical solution:

[0015] According to the loading capacity of 0.1~1mg / cm 2 , Pt / C is sprayed on the surface of the anion exchange membrane to prepare the cathode material.

[0016] Through the above technical solution, this application uses Pt / C as the core catalytic material of the cathode, and its loading directly affects the initial performance and long-term stability of the electrolyzer: too low loading may lead to insufficient catalytic activity, affecting the electrolysis efficiency; too high loading will increase material costs and may increase the mass transfer overpotential due to the excessive thickness of the catalytic layer. By limiting the loading range, the catalytic activity of the cathode is guaranteed and material waste is avoided. In addition, the ultrasonic spraying process ensures the close bonding of the catalyst and the membrane, reduces the interface resistance, and improves the ion transfer efficiency. The selection of raw materials and the optimization of process parameters enable the cathode to stably participate in the reaction in the accelerated test, avoiding test errors caused by catalyst shedding or activity decay, thereby ensuring the accuracy and repeatability of the accelerated test results.

[0017] Furthermore, the anode material includes self-supporting nickel-iron double hydroxide, and the gas diffusion layer is carbon paper.

[0018] Through the above technical solution, the anode in the technical solution of this application adopts self-supporting nickel-iron bimetallic hydroxide, and the gas diffusion layer is carbon paper. The self-supporting nickel-iron bimetallic hydroxide has a three-dimensional porous structure, which not only provides abundant catalytic active sites, but also avoids the shedding problem of traditional supported catalysts through its self-supporting characteristics; the synergistic effect of the nickel-iron bimetallic further improves the catalytic activity and corrosion resistance, ensuring that the anode can still operate stably at high current density. Carbon paper is used for the gas diffusion layer because it has good conductivity, porosity and mechanical strength, which can effectively avoid the increase of local overpotential caused by poor gas diffusion and reduce the risk of non-uniform degradation. The combination of the two enables the membrane electrode to withstand more harsh working conditions in accelerated tests, thereby more realistically reflecting the degradation mechanism in actual use and improving the reliability of the test results.

[0019] Furthermore, the activation treatment parameters are: at a constant current density of 0.5 A / cm 2 ~2A / cm 2 The running time is 0.5h~1h.

[0020] Through the above technical solution, this application defines the key parameters of the activation treatment. The core purpose of the activation treatment is to enable the components in the electrolytic cell to reach a dynamic equilibrium state, eliminate the initial instability factors after assembly, and ensure the accuracy of subsequent test data. If the current density is too low or the time is too short, the components may not be fully activated, and the voltage fluctuations and data dispersion in subsequent tests may be large; if the current density is too high or the time is too long, it may induce material degradation in advance, affecting the initial benchmark of the test. By limiting the parameter range, the activation effect is guaranteed while avoiding additional damage to the material, providing a reliable "initial performance baseline" for accelerated testing, thereby ensuring the accuracy of subsequent decay rate calculations.

[0021] Furthermore, the rated current density is 1A / cm 2 ~2A / cm 2 .

[0022] Through the above technical solution, this application limits the range of rated current density. If the rated current is too low, it cannot effectively reflect the load level under actual operating conditions, resulting in a disconnect between the accelerated test and the real-world scenario. If the rated current is too high, it may directly trigger rapid degradation of the material. By limiting the range, it not only matches the actual application conditions, but also provides a reasonable "comparison benchmark" for subsequent high-current stages, thereby more comprehensively evaluating the long-term stability of the material.

[0023] Furthermore, the high current density is 2 to 4 times the rated current density.

[0024] Through the above technical solution, this application defines the multiple relationship between high current density and rated current density. By applying a current 2 to 4 times higher than the rated value, the reaction rate on the electrode surface can be significantly increased, exacerbating ion transport resistance and material corrosion, thereby inducing a degradation process similar to long-term operation in a short period of time. This ensures acceleration efficiency while avoiding distortion caused by "over-acceleration", ensuring that test results truly reflect the attenuation characteristics of the material in actual long-term operation, providing an effective basis for material screening.

[0025] Furthermore, the period of the periodic alternating operation is 1 to 3 hours per cycle.

[0026] Through the above technical solution, this application specifies the cycle duration of periodic alternating operation. Periodic alternation is a key design for simulating actual dynamic working conditions. If the cycle is too short, the current may be frequently switched, which will increase the mechanical stress of the electrolytic cell and induce non-actual damage; if the cycle is too long, it will not be able to effectively simulate the real scenario of "short-term high load-long-term normal load", reducing the authenticity of the test. By limiting the cycle range, it can not only cover the load fluctuation frequency in most actual applications, but also accumulate the degradation effect during the alternation process, so as to more accurately evaluate the durability of the material under dynamic working conditions.

[0027] Furthermore, the operating temperature of the anion exchange membrane electrolyzer described in step S1 is 60-80° C., and an electrolyte is provided in the anion exchange membrane electrolyzer, and the electrolyte includes a KOH solution with a concentration of 0.1-1 mol / L.

[0028] Through the above technical solution, this application limits the operating temperature and electrolyte concentration of the electrolytic cell, which not only ensures the ion transmission efficiency, but also avoids "unnatural degradation" caused by excessive temperature or concentration, so that the accelerated test can truly reflect the long-term stability of the material under "moderate acceleration" conditions, ensuring the reliability and practicality of the test results.

[0029] Furthermore, the self-supporting nickel-iron double hydroxide is NiFe-LDH.

[0030] Furthermore, the self-supporting nickel-iron double hydroxide is prepared by the following technical solution: nickel foam is immersed in a ferric nitrate solution, then taken out, washed, and dried to obtain NiFe-LDH.

[0031] In summary, this application has the following beneficial effects:

[0032] First, this application realizes efficient evaluation of the life of the electrolyzer through a closed-loop process of "assembly-activation-three-stage accelerated testing-evaluation". Among them, the raw material selection and process design are deeply integrated: the cathode, anode and gas diffusion layer are used in the assembly stage to ensure the catalytic activity and structural stability of the membrane electrode; the activation stage is operated by constant current to make the electrolyzer enter a stable state, providing a reliable benchmark for subsequent tests; the three-stage accelerated test simulates the load fluctuations in actual applications through dynamic working conditions, combined with the acceleration conditions of high current density, and can induce a degradation process similar to long-term steady-state operation within 300 hours. This method shortens the traditional steady-state test cycle of several months or even a year to a few weeks, while ensuring the consistency of the test results with the actual working conditions, providing an efficient and reliable evaluation tool for new material development and process optimization.

[0033] Second, this application defines the key parameters of the activation treatment. The core purpose of the activation treatment is to enable the components in the electrolytic cell to reach a dynamic equilibrium state, eliminate the initial instability factors after assembly, and ensure the accuracy of subsequent test data. If the current density is too low or the time is too short, the components may not be fully activated, and the voltage fluctuations and data dispersion in subsequent tests may be large; if the current density is too high or the time is too long, it may induce material degradation in advance, affecting the initial benchmark of the test. By limiting the parameter range, the activation effect is guaranteed while avoiding additional damage to the material, providing a reliable "initial performance baseline" for accelerated testing, thereby ensuring the accuracy of subsequent decay rate calculations.

[0034] Third, this application specifies the cycle duration of periodic alternating operation. Periodic alternation is a key design for simulating actual dynamic working conditions. If the cycle is too short, the current may be frequently switched, increasing the mechanical stress of the electrolytic cell and inducing non-actual damage; if the cycle is too long, it will not be able to effectively simulate the real scenario of "short-term high load-long-term normal load", reducing the authenticity of the test. By limiting the cycle range, it can not only cover the load fluctuation frequency in most actual applications, but also accumulate the degradation effect during the alternation process, thereby more accurately evaluating the durability of the material under dynamic conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a graph showing the accelerated durability test data in Example 2 of the present application;

[0036] Figure 2 This is a data chart of the constant working condition durability test in Example 2 of this application. DETAILED DESCRIPTION

[0037] The present application is further described in detail below with reference to the embodiments.

[0038] Preparation Example 1

[0039] Pt / C catalyst, quaternary ammonium polysulfone ionomer, water and isopropyl alcohol were mixed in a mass ratio of 1:0.1:10:20 and then ultrasonically dispersed to obtain Pt / C slurry 1.

[0040] Preparation Example 2

[0041] Pt / C catalyst, polyarylpiperidine ionomer, water and isopropanol were mixed in a mass ratio of 1:0.4:15:60 and then ultrasonically dispersed to obtain Pt / C slurry 2.

[0042] Preparation Example 3

[0043] Ru / C catalyst, polynorbornene ionomer, water and isopropyl alcohol were mixed in a mass ratio of 1:0.7:20:100 and then ultrasonically dispersed to obtain Ru / C slurry 1.

[0044] Example 1

[0045] A durability testing method for an anion exchange membrane electrolyzer includes the following testing steps:

[0046] S1. Electrolytic cell assembly: The loading capacity is 1 mg / cm 2 The (60wt%) Pt / C slurry 1 was sprayed onto the anion exchange membrane as the cathode, the self-supporting nickel-iron double hydroxide was used as the anode, and the carbon paper was used as the gas diffusion layer of the cathode. The cathode, carbon paper, and anode sprayed on the membrane were assembled to obtain a membrane electrode. The effective reaction area of ​​the membrane electrode was 5cm 2 Finally, the membrane electrode, flow channel plate, collector plate, and sealing gasket are assembled into an AEM electrolyzer. The operating temperature of the electrolyzer is 60°C, the electrolyte is 1 mol / L KOH solution, the anode is supplied with liquid, and the cathode is not supplied with liquid.

[0047] S2, activation and initial test: at 0.5A / cm 2 , 1A / cm 2 The AEM electrolytic cell was activated by running at different current densities for 0.5 h, and then polarization curve test and electrochemical impedance spectroscopy test were performed.

[0048] S3, accelerated durability test:

[0049] (a) 1A / cm 2 Run at rated current density for 100h;

[0050] (b) 4A / cm 2 Run at high current density for 100h;

[0051] (c) 1A / cm 2 Rated current density is 4-8A / cm 2 The high current density was operated alternately for 100 h, and the two current densities were operated for 1 h each as one cycle.

[0052] S4. Post-test evaluation: Retest the polarization curve and electrochemical impedance spectrum, calculate the attenuation rate of the electrolyzer and predict its service life, and the durability test of the anion exchange membrane electrolyzer is completed.

[0053] Example 2

[0054] A durability testing method for an anion exchange membrane electrolyzer includes the following testing steps:

[0055] S1. Electrolytic cell assembly: The loading capacity is 1 mg / cm 2 The (60wt%) Pt / C slurry 2 was sprayed onto carbon paper as the cathode, and the self-supporting nickel-iron double hydroxide was used as the anode. The cathode, anode, and membrane sprayed on the carbon paper were assembled to obtain a membrane electrode. The effective reaction area of ​​the membrane electrode was 5cm 2 Finally, the membrane electrode, flow channel plate, collector plate, and sealing gasket are assembled into an AEM electrolyzer. The operating temperature of the electrolyzer is 60°C, the electrolyte is 1 mol / L KOH solution, the anode is supplied with liquid, and the cathode is not supplied with liquid.

[0056] S2, activation and initial test: at 0.5A / cm 2 , 1A / cm 2 The AEM electrolytic cell was activated by running at different current densities for 0.5 h, and then polarization curve test and electrochemical impedance spectroscopy test were performed.

[0057] S3, accelerated durability test:

[0058] (a) 1A / cm 2 Run at rated current density for 100h;

[0059] (b) 4A / cm 2 Run at high current density for 100h;

[0060] (c) 1A / cm 2 Rated current density is 4-8A / cm 2 The high current density was operated alternately for 100 h, and the two current densities were operated for 2 h each as one cycle.

[0061] S4. Post-test evaluation: Retest the polarization curve and electrochemical impedance spectrum, calculate the attenuation rate of the electrolyzer and predict its service life, and the durability test of the anion exchange membrane electrolyzer is completed.

[0062] Example 3

[0063] A durability testing method for an anion exchange membrane electrolyzer includes the following testing steps:

[0064] S1. Electrolytic cell assembly: The loading capacity is 1 mg / cm2 50wt% Ru / C slurry 1 was sprayed onto an anion exchange membrane as the cathode, self-supporting nickel-iron double hydroxide as the anode, and carbon paper as the gas diffusion layer of the cathode. The cathode, carbon paper, and anode sprayed on the membrane were assembled to obtain a membrane electrode. The effective reaction area of ​​the membrane electrode was 5cm 2 Finally, the membrane electrode, flow channel plate, collector plate, and sealing gasket are assembled into an AEM electrolyzer. The operating temperature of the electrolyzer is 80°C, the electrolyte is 1 mol / L KOH solution, the anode is supplied with liquid, and the cathode is not supplied with liquid.

[0065] S2, activation and initial test: at 0.5A / cm 2 , 1A / cm 2 The AEM electrolytic cell was activated by running at different current densities for 0.5 h, and then polarization curve test and electrochemical impedance spectroscopy test were performed.

[0066] S3, accelerated durability test:

[0067] (a) 1A / cm 2 Run at rated current density for 100h;

[0068] (b) 4A / cm 2 Run at high current density for 100h;

[0069] (c) 1A / cm 2 Rated current density and 4A / cm 2 The high current density was operated alternately for 100 h, and the two current densities were operated for 1 h each as one cycle.

[0070] S4. Post-test evaluation: Retest the polarization curve and electrochemical impedance spectrum, calculate the attenuation rate of the electrolyzer and predict its service life, and the durability test of the anion exchange membrane electrolyzer is completed.

[0071] Performance testing

[0072] The test results in Examples 1-3 were evaluated, wherein:

[0073] After 300h accelerated test in Example 1, 1.5A / cm 2 The corresponding initial voltage at the rated current density is 1.74V. After the test, the voltage rises to 1.92V, the voltage increase is 180mV, the decay rate is 0.6mV / h, and the life is 330h. At 1.5A / cm 2 After running for 1000 hours at a constant current density, the initial voltage increased from 1.74V to 1.89V, with a voltage increase of 150mV, a decay rate of 0.15mV / h, and a lifespan of 1330h.

[0074] After 300h accelerated endurance test in Example 2, 1A / cm 2 The corresponding voltage under the current density increases from 1.86V to 1.92V, an increase of 60mV, a decay rate of 0.2mV / h, and a lifespan of about 1000h; while at 1A / cm 2 After running for 1000 hours at a constant current density, the voltage increased from 1.86V to 1.9V, an increase of 40mV, a decay rate of 0.04mV / h, and a lifespan of approximately 5000h.

[0075] In Example 3, after 300h accelerated test, 1A / cm 2 The corresponding initial voltage at the rated current density is 1.65V. After the test, the voltage rises to 1.76V, the voltage increase is 110mV, the decay rate is 0.36mV / h, and the life span is 550h. 2 After running for 1000 hours at a constant current density, the initial voltage of 1.65V increased to 1.75V, the voltage increase was 100mV, the decay rate was 0.1mV / h, and the lifespan was about 2000h.

[0076] Combining the above results Figure 1-2 The data shows that the voltage increase of the accelerated test is significantly higher than that of the constant working condition, the attenuation rate is 3.6 to 5 times that of the constant working condition, and the test cycle is shortened by 3 to 5 times.

[0077] It further explains that the technical solution of this application realizes efficient evaluation of the life of the electrolytic cell through a closed-loop process of "assembly-activation-three-stage accelerated testing-evaluation". The three-stage accelerated test simulates the load fluctuations in actual applications through dynamic working conditions, combined with the accelerated conditions of high current density, and can induce a degradation process similar to long-term steady-state operation within 300 hours. This method shortens the traditional steady-state test cycle of several months or even one year to several weeks through the rational selection of raw materials and scientific design of processes, while ensuring the consistency of test results with actual working conditions, providing an efficient and reliable evaluation tool for new material development and process optimization.

[0078] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

[0079] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of conflict, the definitions in this specification shall prevail.

[0080] When this specification uses the prefix "well known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, the objects introduced by the prefix include those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become generally recognized in the art to be suitable for similar purposes.

[0081] In the context of this specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

Claims

1. A method for testing the durability of an anion exchange membrane electrolyzer, characterized in that: The test steps include: S1. Electrolyzer assembly: Cathode material, anode material and gas diffusion layer are assembled into membrane electrode, and then assembled with flow channel plate, collector plate and sealing gasket into an anion exchange membrane electrolyzer; S2. Activation and initial testing: The electrolytic cell was operated at a constant current density for activation, followed by polarization curve and electrochemical impedance spectroscopy testing. S3, Accelerated Endurance Test: Conduct the following three phases of testing in sequence: (a) Operation at rated current density for 100 h; (b) Operation at high current density for 100 h; (c) Rated current density and high current density are periodically alternating for 100 h; S4. Post-test evaluation: Retest the polarization curve and electrochemical impedance spectrum, calculate the attenuation rate of the electrolyzer and predict the service life, and then complete the durability test of the anion exchange membrane electrolyzer; The rated current density is 1A / cm2~2A / cm2; The high current density is 2 to 4 times the rated current density; The period of the periodic alternating operation is 1 to 3 hours per cycle.

2. The method for testing the durability of an anion exchange membrane electrolyzer according to claim 1, wherein: The cathode material is made by the following technical solution: The cathode material can be prepared by spraying Pt / C on the surface of the anion exchange membrane at a loading of 0.1~1 mg / cm2.

3. The method for testing the durability of an anion exchange membrane electrolyzer according to claim 1, wherein: The anode material includes self-supporting nickel-iron double hydroxide, and the gas diffusion layer is carbon paper.

4. The method for testing the durability of an anion exchange membrane electrolyzer according to claim 1, wherein: The parameters of the activation treatment are: running time of 0.5h~1h at a constant current density of 0.5A / cm2~2A / cm2.

5. The method for testing the durability of an anion exchange membrane electrolyzer according to claim 1, wherein: The operating temperature of the anion exchange membrane electrolyzer described in step S1 is 60-80° C., and an electrolyte is provided in the anion exchange membrane electrolyzer, and the electrolyte includes a KOH solution with a concentration of 0.1-1 mol / L.

6. The method for testing the durability of an anion exchange membrane electrolyzer according to claim 3, wherein: The self-supporting nickel-iron double hydroxide is NiFe-LDH.

7. The method for testing the durability of an anion exchange membrane electrolyzer according to claim 6, wherein: The self-supporting nickel-iron double hydroxide is prepared by the following technical solution: nickel foam is immersed in a ferric nitrate solution, then taken out, washed, and dried to obtain NiFe-LDH.

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