A method for analyzing the degree of coverage of anode gas of a proton exchange membrane water electrolyzer

Abstract

This application belongs to the field of proton exchange membrane water electrolysis for hydrogen production technology, specifically disclosing a method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer. The technical solution of this application first measures the polarization curve of the water electrolyzer under target operating conditions; then, it obtains the correction potential by subtracting the ohmic overpotential of the water electrolyzer from the voltage; a Tafel curve is plotted with the correction potential as the ordinate and the voltage as the abscissa; on the Tafel curve, all data points within the interval where no mass transfer loss is observed are selected for linear fitting to obtain the Tafel slope and the first intercept; for a single data point within the interval where mass transfer loss is observed, the Tafel slope is substituted into the linear equation to determine the second intercept corresponding to the single data point; the anode gas coverage is determined based on the difference between the first intercept and the second intercept. This application realizes a simple and quantifiable method for analyzing the anode gas coverage of a water electrolyzer, with good universality and engineering application prospects.

Description

Technical Field

[0001] This application belongs to the field of proton exchange membrane water electrolysis hydrogen production technology, and more specifically, relates to a method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis for hydrogen production boasts advantages such as high current density, high hydrogen purity, and rapid dynamic response, making it a promising technology for renewable energy hydrogen production. Employing PEM water electrolysis on offshore floating platforms allows for the direct conversion of offshore wind power into green hydrogen. This technology helps reduce losses during long-distance power transmission and mitigates the impact of fluctuating wind power grid connections on grid stability, enabling source-end absorption. However, under the high current density operating conditions corresponding to high-power offshore wind power input, the oxygen evolution reaction at the anode of the PEM electrolyzer is intense, generating a large amount of oxygen on the catalyst surface. If this oxygen fails to dissipate in time, it forms a localized gas cover at the catalyst active sites, hindering the transport of liquid reactants (water) to these sites and significantly reducing the effective electrochemical reaction area. This mass transfer limitation will cause a sharp rise in cell voltage (intensified concentration polarization), leading to increased system energy consumption. It may also accelerate the performance degradation of key components such as the catalyst layer and proton exchange membrane due to excessively high local current density or unstable reaction interface, thereby restricting the efficient and long-term operation of PEM electrolyzers in marine hydrogen production environments.

[0003] Therefore, to optimize the performance of offshore wind power hydrogen production systems, it is essential to accurately analyze and quantitatively evaluate the mass transfer process inside the PEM electrolyzer, especially on the anode side. Existing research methods largely focus on macroscopic performance parameter analysis (such as mass transfer overpotential measurement and electrochemical impedance spectroscopy) or rely on complex in-situ visualization techniques to directly capture gas-liquid transport behavior. The former struggles to establish a direct quantitative correlation between bubble coverage and performance loss; the latter involves complex and costly equipment, and is difficult to integrate into actual industrial installations for online diagnostics. Currently, there is a lack of an analytical method that is based on conventional electrochemical test data, is easy to operate, low-cost, and capable of quantitatively characterizing the anode gas coverage and its corresponding mass transfer loss. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this application is to provide a method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer, aiming to solve the technical problems of the complexity and high cost of current PEM water electrolyzer anode gas coverage analysis methods based on in-situ visualization technology.

[0005] The first aspect of this application relates to a method for analyzing the anode gas coverage in a proton exchange membrane water electrolyzer, comprising: The polarization curve of the water electrolyzer under the target operating conditions was measured, and the polarization curve recorded the voltage corresponding to different current densities; The corrected potential is obtained by subtracting the ohmic overpotential of the water electrolyzer from the voltage. by Plot a Tafel curve with the x-axis as the horizontal axis and the corrected potential as the y-axis, where... The current density is mentioned. On the Tafel curve, all data points in the interval where no mass transfer loss is observed are selected for linear fitting to obtain the Tafel slope and the first intercept; the equation of the straight line is determined by a single data point in the interval where mass transfer loss is observed and the Tafel slope, and the second intercept corresponding to the single data point is obtained from the equation of the straight line. The degree of anode gas coverage in the water electrolyzer is determined based on the difference between the first intercept and the second intercept.

[0006] Preferably, the degree of anode gas coverage increases monotonically as the difference increases.

[0007] Preferably, the degree of anode gas coverage increases monotonically with the increase of the difference, specifically: ; in, The first intercept is... The second intercept, Let the Tafel slope be... The coverage degree of the anode gas is referred to as the coverage coefficient.

[0008] Preferably, in the Tafel curve, the linear variation range is the range in which no mass transfer loss is observed; the nonlinear variation range is the range in which mass transfer loss is observed.

[0009] Preferably, the ohmic overpotential is obtained by the following method: The ohmic impedance of the water electrolyzer was measured at different current densities. The ohmic overpotential is obtained by multiplying the ohmic impedance by the current at the corresponding data point.

[0010] Preferably, the ohmic impedance of the water electrolyzer is measured at different current densities, specifically as follows: Electrochemical impedance spectroscopy of the water electrolyzer at different current densities was measured using an electrochemical workstation. The ohmic impedance at different current densities is read from the electrochemical impedance spectrum.

[0011] Preferably, the polarization curve of the water electrolyzer under the target operating conditions is determined by measuring the curve of voltage change with current density under the target operating conditions, i.e., the polarization curve, using a slow scanning or point-by-point steady-state method.

[0012] In a second aspect, this application provides an electronic device, comprising: at least one memory for storing a program; and at least one processor for executing the program stored in the memory, wherein when the program stored in the memory is executed, the processor is configured to execute the method described in the first aspect or any possible implementation thereof.

[0013] Thirdly, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to perform the method described in the first aspect or any possible implementation thereof.

[0014] Fourthly, this application provides a computer program product that, when run on a processor, causes the processor to perform the method described in the first aspect or any possible implementation thereof.

[0015] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) The method for analyzing the anodic gas coverage in this application is based on polarization curves and Tafel curves. Intrinsic kinetic parameters are obtained through Ohm correction, and the gas coverage coefficient is quantitatively calculated by using the intercept changes of the fitting equation in the linear and nonlinear variation ranges. The required data comes from simple electrochemical detection, which is simpler than in-situ visualization observation techniques and does not require complex and costly visualization equipment.

[0016] (2) The method for analyzing the degree of anode gas coverage proposed in this application proposes a quantitative equation for the degree of anode gas coverage, which makes the assessment of the fuzzy phenomenon of anode gas coverage rise from qualitative description to quantitative analysis. The results are more accurate and scientific, providing a basis for in-depth research on important engineering issues such as gas diffusion law and water transport limitation, and can be used as a key performance indicator for assessing the mass transfer health status of electrolytic cell membrane electrodes.

[0017] (3) The technical solution of this application is not only applicable to the research of small electrolytic cells in the laboratory, but can also be extended to the indirect diagnosis and analysis of mass transfer status of offshore platform fuel cell modules and even system level, and has good universality and engineering application prospects. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the steps for measuring and analyzing the anode gas coverage of a proton exchange membrane water electrolyzer provided in the embodiments of this application.

[0019] Figure 2 This is a schematic diagram of the polarization curve of the proton exchange membrane water electrolyzer provided in the embodiments of this application.

[0020] Figure 3 This is a schematic diagram of the electrochemical impedance spectroscopy of a proton exchange membrane water electrolyzer provided in the embodiments of this application.

[0021] Figure 4 This is a schematic diagram of the Tafel curve of the proton exchange membrane water electrolyzer provided in the embodiments of this application after removing the influence of ohmic overpotential.

[0022] Figure 5 This is a schematic diagram of the curve showing the change of the anode gas coverage coefficient with current density in the proton exchange membrane water electrolyzer provided in the embodiments of this application.

[0023] Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0025] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the symbol " / " indicates that the related objects are in an "or" relationship, for example, A / B means A or B.

[0026] In this application, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages.

[0027] In this application, the term "electrical connection" can refer to a direct circuit connection or a signal transmission via a communication protocol.

[0028] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0029] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0030] The embodiments of this application are described below with reference to the accompanying drawings.

[0031] Example 1: Based on the anode gas coverage analysis method for water electrolyzers described in this application, the hydrogen production performance of a certain PEM (proton exchange membrane) water electrolyzer was determined. The effective reaction area of ​​this water electrolyzer is... The water electrolyzer adopts a single-sided anode water supply mode. For this water electrolyzer, the electrochemical and mass transfer characteristics of the anode are the main factors limiting the performance of the water electrolyzer, while the influence of cathode polarization is negligible. Therefore, the essence of testing the hydrogen production performance of this water electrolyzer is to determine the electrochemical and mass transfer performance of the anode.

[0032] like Figure 1 As shown, the specific steps include: (1) Set the working temperature of the water electrolysis cell to be The influent flow rate is Using an electrochemical workstation or other electrochemical measurement tools, the water electrolyzer was tested at a current density of [value missing] using a slow scan or point-by-point steady-state method. Polarization curves within the range, i.e., voltage With current density The changing curve, when each sampling point remains stable The above records the results. Note that the sampling points set in the low current density range should not be too sparse, generally no less than 4. The sampling data is as follows: Figure 2 As shown.

[0033] At this point, the voltage data in the polarization curve contains the three main overpotentials during the operation of the electrolyzer: Activation overpotential: determined by electrochemical reaction kinetics, it dominates in the low current density region.

[0034] Ohmic overpotential: caused by the ohmic impedance of the electrolytic cell, it is characterized by a linear increase in voltage with current.

[0035] Mass transfer overpotential: In the high current density region, the voltage deviates further from linearity due to the obstruction of reactant (water) transport or the coverage of active sites by products (oxygen).

[0036] (2) Electrochemical impedance spectroscopy (EIS) of the electrolytic cell was measured using an electrochemical workstation when it was operating at different current densities. The ohmic impedance at different current densities was then read from the EIS. .

[0037] Electrochemical impedance spectroscopy, such as Figure 3 As shown, the left side of the low-frequency semicircle is adjacent to the real part of the impedance. The value corresponding to the intersection of the axes is the ohmic impedance. Its measured value is approximately The ohmic impedance of the polarization curve measured in the first step is corrected according to the following formula: ; The corrected potential is obtained, which only reflects the activation overpotential and the mass transfer overpotential. In the formula, For voltage The corresponding current.

[0038] by The horizontal axis represents the corrected potential. Plot the Tafel curve of the PEM water electrolyzer as the ordinate, as follows: Figure 4 As shown. Among them, To correct the potential The corresponding current density.

[0039] This Tafel curve reflects the combined effects of electrochemical kinetics and mass transfer processes.

[0040] (3) In Figure 4 In the Tafel curves shown, the corrected potential is in the region where no mass transfer loss is observed. Follow The increase is linear, and within the range exhibiting mass transfer loss, the correction potential... Follow The increase transforms into a rapid, nonlinear growth. Therefore, the correction potential is distinguished by the linear and nonlinear variation intervals in the Tafel curve. Whether it is affected by mass transfer loss.

[0041] Figure 4 In the Tafel curve shown, The correction potential is in the range of -2 to -1. It grows linearly. Corrected potential in the range of -1 to 0 It exhibits non-linear growth.

[0042] Linear fitting was performed on all data points within the linear variation interval. Within this interval, the electrolyzer did not exhibit any mass transfer loss, and the correction potential was adjusted. It is controlled solely by the electrochemical activation process.

[0043] Linear fitting yields the first equation: ; In the equation Let the Tafel slope be... The first intercept can be used to calculate the exchange current density per unit electrochemical active surface area of ​​the anode. Charge transfer coefficient These two parameters describe the intrinsic electrochemical activity parameters of the anode catalyst layer.

[0044] First intercept With Tafel slope The following relationship must be satisfied: ; ; in Let be the ideal gas constant. This refers to the operating temperature of the electrolytic cell. It is Faraday's constant. This represents the active area of ​​the anode. This represents the anodic electrochemical active surface area. This is the anode equilibrium potential.

[0045] The calculation in this embodiment is , .

[0046] (4) Figure 4 The corrected potential is located within the nonlinear growth range of the Tafel curve shown. The distribution is higher than the fitted line of the data points within the linear growth interval. This is due to the influence of gas coverage on the active sites of the anode catalyst layer, and the water electrolysis process exhibits the effect of mass transfer loss.

[0047] The equation of the straight line is determined by a single data point within the nonlinear growth interval of the Tafel curve and the Tafel slope. The intercept of the straight line equation is the second intercept corresponding to the single data point. The equation of the straight line is specifically transformed as follows: ; in The anode gas coverage factor characterizes the proportion of effective active surface area lost by oxygen coverage in the anode catalyst layer to participate in the electrochemical reaction. Eliminating identical terms from the first equation and the linear equation yields the second intercept. First intercept and anode gas coverage factor Functional relationship between them: ; The anode gas coverage coefficient can be obtained from the above formula. (Anode gas coverage) varies with the second intercept and first intercept The difference increases monotonically, and the evolution of the anode gas coverage coefficient with current density can be calculated using the above formula. The specific evolution process is as follows: Figure 5 As shown.

[0048] according to Figure 5 As shown Curve, combined Figure 3 The electrochemical impedance spectroscopy analysis shown illustrates the electrochemical and mass transfer processes in the water electrolyzer. Calculations yield... The curve is roughly S-shaped. Follow The process of change can be divided into three stages: In the first stage, at current density Less than (In the low current density range) Gas coverage factor Maintaining a value near 0, there is no mass transfer loss during the water electrolysis process. This is because the gas diffusion layer and the catalyst layer are hydrophilic. During the oxygen evolution process, the oxygen bubbles generated quickly detach from the catalyst layer and enter the gas diffusion layer, and there is basically no gas coverage on the surface of the catalyst layer. Second stage, current density exist Within the range (high current density range), as the current density increases, the gas coverage coefficient... The value gradually increases to close to 1, indicating that as the gas generation rate increases, the gas begins to accumulate and cover some active sites in the catalyst layer due to the limitation of the gas transport rate in the gas diffusion layer. This results in the polarization curve showing a certain mass transfer overpotential, which slowly increases with the increase of current density. Third stage, current density Greater than (In the high current density range) Gas coverage factor When the value is kept around 1, the gas occupies most of the active sites, and the mass transfer overpotential rises rapidly. However, due to the hydrophilicity of the gas diffusion layer and the catalyst layer, the anode can still maintain a certain degree of water transport, so the water electrolysis reaction can continue.

[0049] Gas coverage coefficient It can be used as an indicator and basis for analyzing the gas-liquid two-phase flow transport characteristics in the catalyst layer and gas diffusion layer of a PEM water electrolyzer.

[0050] Based on the methods in the above embodiments, this application provides an electronic device, such as... Figure 6As shown, the electronic device may include a processor, a communications interface, a memory, and a communication bus, wherein the processor, communications interface, and memory communicate with each other via the communication bus. The processor can invoke logical instructions stored in the memory to execute the methods described in the above embodiments.

[0051] Furthermore, the logical instructions in the aforementioned memory can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0052] Based on the methods in the above embodiments, this application provides a computer-readable storage medium storing a computer program that, when run on a processor, causes the processor to execute the methods in the above embodiments.

[0053] Based on the methods in the above embodiments, this application provides a computer program product that, when run on a processor, causes the processor to execute the methods in the above embodiments.

[0054] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0055] The method steps in this application embodiment can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.

[0056] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0057] It is understood that the various numerical designations used in the embodiments of this application are merely for the convenience of description and are not intended to limit the scope of the embodiments of this application.

[0058] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for analyzing the anode gas coverage in a proton exchange membrane water electrolyzer, characterized in that, include: The polarization curve of the water electrolyzer under the target operating conditions was measured, and the polarization curve recorded the voltage corresponding to different current densities; The corrected potential is obtained by subtracting the ohmic overpotential of the water electrolyzer from the voltage. by Plot a Tafel curve with the x-axis as the horizontal axis and the corrected potential as the y-axis, where... The current density is mentioned. On the Tafel curve, all data points in the interval where no mass transfer loss is observed are selected for linear fitting to obtain the Tafel slope and the first intercept; the equation of the straight line is determined by a single data point in the interval where mass transfer loss is observed and the Tafel slope, and the second intercept corresponding to the single data point is obtained from the equation of the straight line. The degree of anode gas coverage in the water electrolyzer is determined based on the difference between the first intercept and the second intercept.

2. The method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer according to claim 1, characterized in that, The degree of anode gas coverage increases monotonically as the difference increases.

3. The method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer according to claim 2, characterized in that, The degree of anolyte gas coverage increases monotonically with the increase of the difference, specifically: ； in, The first intercept is... The second intercept, Let the Tafel slope be... The coverage degree of the anode gas is referred to as the coverage coefficient.

4. The method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer according to claim 1, characterized in that, In the Tafel curve, the linear variation range is the range in which no mass transfer loss is observed; the nonlinear variation range is the range in which mass transfer loss is observed.

5. The method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer according to claim 1, characterized in that, The ohmic overpotential is obtained by the following method: The ohmic impedance of the water electrolyzer was measured at different current densities. The ohmic overpotential is obtained by multiplying the ohmic impedance by the current at the corresponding data point.

6. The method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer according to claim 5, characterized in that, The ohmic impedance of the water electrolyzer under different current densities was measured, specifically as follows: Electrochemical impedance spectroscopy of the water electrolyzer at different current densities was measured using an electrochemical workstation. The ohmic impedance at different current densities is read from the electrochemical impedance spectrum.

7. The method for analyzing the anode gas coverage of a proton exchange membrane water electrolyzer according to claim 1, characterized in that, The polarization curve of the water electrolyzer under the target operating conditions is determined by measuring the voltage-current density curve of the water electrolyzer under the target operating conditions, i.e., the polarization curve, using a slow scanning or point-by-point steady-state method.

8. An electronic device, characterized in that, Includes memory and one or more processors; The memory is coupled to the one or more processors, and the memory is used to store computer program code, the computer program code including computer instructions; The one or more processors invoke the computer instructions to cause the electronic device to perform the method as described in any one of claims 1-7.

9. A computer-readable storage medium comprising instructions, characterized in that: When the instructions are executed on an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-7.

10. A computer program product, comprising a computer program or instructions, characterized in that: When the computer program or instructions are run on an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-7.

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