Method for evaluating comprehensive performance of membrane electrode of high-temperature proton exchange membrane

Abstract

The invention relates to the technical field of proton exchange membranes, in particular to a comprehensive performance evaluation method for a membrane electrode of a high-temperature proton exchange membrane. The comprehensive performance evaluation method for the high-temperature proton exchange membrane electrode comprises the following steps: constructing a hierarchical structure model for evaluating the comprehensive performance of the membrane electrode according to the dopant type of a proton exchange membrane; the hierarchical structure model comprises a target layer, a criterion layer and an index layer; constructing a judgment matrix of the hierarchical structure model; obtaining experimental data of a plurality of second type parameters of the index layer corresponding to the proton exchange membrane; evaluating a first score for each of the plurality of second type parameters of the index layer according to the experimental data; evaluating a comprehensive score of the comprehensive performance of the target layer according to the first score and the judgment matrix; and carrying out normalization processing on the comprehensive score. Therefore, the problem that the existing comprehensive performance evaluation method for the membrane electrode of the high-temperature proton exchange membrane is not systematized, quantified, objective and efficient enough is solved.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane technology, and more specifically, to a method for evaluating the comprehensive performance of high-temperature proton exchange membrane electrodes. Background Technology

[0002] A hydrogen fuel cell is a clean power device that directly converts the chemical energy of hydrogen and oxygen into electrical energy through an electrochemical reaction. It boasts significant advantages such as zero emissions, high energy conversion efficiency, and quiet operation, making it widely applicable. The membrane electrode assembly (MEA) of a hydrogen fuel cell comprises a proton exchange membrane, a catalyst layer, and a gas diffusion layer. As the core component of the hydrogen fuel cell, the proton exchange membrane performs the dual functions of directional proton conduction and isolating hydrogen and oxygen. The overall performance of the MEA directly determines the fuel cell's output power, operational stability, and lifespan.

[0003] Currently, high-temperature proton exchange membranes modified with polybenzimidazole (PBI) as the substrate and doped with phosphoric acid (PA) have become a key technological path to solve the bottleneck of low-temperature proton exchange membrane applications due to their characteristics such as strong catalyst resistance to CO poisoning, simplified thermal management system, and high efficiency of reaction kinetics at high temperature conditions of 120-200℃.

[0004] However, there is an inherent contradiction in the performance optimization of PBI-based high-temperature proton exchange membranes: although the introduction of PA can improve proton conduction efficiency, it will destroy the stability of PBI molecular chains, leading to a decrease in the mechanical properties and long-term operational stability of the membrane material. This makes it necessary to balance the complex trade-offs between multiple dimensions of the membrane electrode comprehensive performance evaluation.

[0005] Existing technologies for comprehensive performance evaluation of membrane electrodes have significant limitations: First, directly fabricating membrane electrodes for power density and attenuation testing results in long testing cycles and high costs, severely hindering the research and development process. Second, relying on single or a few performance indicators (such as focusing only on proton conductivity or power density) makes it difficult to comprehensively reflect the overall performance of membrane electrodes in terms of mechanical support, electrochemical conduction, and long-term stability. Third, the lack of unified standards for multi-indicator evaluation relies mainly on the subjective experience of experts for qualitative or semi-quantitative judgments, resulting in poor repeatability and insufficient objectivity, failing to provide a reliable basis for material screening and formulation optimization. Fourth, the lack of a systematic tool to quantify the inherent trade-offs between performance indicators makes it difficult to support the accurate implementation of research and development decisions.

[0006] Therefore, developing a systematic, quantitative, objective, and efficient method for evaluating the comprehensive performance of high-temperature proton exchange membrane electrodes is a key issue that urgently needs to be addressed in promoting the industrialization of high-temperature hydrogen fuel cell technology. Summary of the Invention

[0007] To address the shortcomings of existing methods for evaluating the comprehensive performance of high-temperature proton exchange membrane electrodes, namely, a lack of systematization, quantification, objectivity, and efficiency, this invention provides a method for evaluating the comprehensive performance of high-temperature proton exchange membrane electrodes, comprising:

[0008] Based on the dopant type of the proton exchange membrane, a hierarchical structure model for evaluating the comprehensive performance of the membrane electrode is constructed. The hierarchical structure model includes a target layer, a criterion layer, and an index layer. The target layer includes the comprehensive performance of the membrane electrode. The criterion layer includes multiple first-type parameters of the proton exchange membrane. The index layer includes multiple second-type parameters of the proton exchange membrane. Each first-type parameter corresponds to multiple second-type parameters. The second-type parameters are the influencing parameters of the corresponding first-type parameters.

[0009] Construct the judgment matrix of the hierarchical structure model;

[0010] Experimental data were obtained for multiple second-type parameters corresponding to the index layer of the proton exchange membrane.

[0011] Based on the experimental data, a first score is evaluated for each of the second type parameters of the indicator layer;

[0012] The comprehensive performance evaluation score of the target layer is based on the first score and the judgment matrix.

[0013] The comprehensive score is then normalized.

[0014] In some embodiments, the judgment matrix for constructing the hierarchical model includes:

[0015] Construct a first judgment matrix from the target layer to the criterion layer; the first judgment matrix includes the first relative importance of any two first type parameters of the criterion layer;

[0016] Construct a second judgment matrix from the criterion layer to the indicator layer; the second judgment matrix includes the second relative importance of any two second type parameters of the indicator layer.

[0017] In some embodiments, the judgment matrix for constructing the hierarchical model further includes:

[0018] The first judgment matrix is ​​sorted hierarchically and a consistency check is performed.

[0019] When the first result of the consistency test of the first judgment matrix is ​​greater than or equal to 0.1, the first relative importance in the first judgment matrix is ​​adjusted, the first judgment matrix is ​​re-sorted hierarchically and a consistency test is performed until the first result is less than 0.1.

[0020] The second judgment matrix is ​​sorted hierarchically and a consistency check is performed.

[0021] If the second result of the consistency test of the second judgment matrix is ​​greater than or equal to 0.1, adjust the second relative importance in the second judgment matrix, re-sort the second judgment matrix hierarchically and perform a consistency test until the second result is less than 0.1.

[0022] In some embodiments, the judgment matrix for constructing the hierarchical model further includes:

[0023] When both the first result and the second result are less than 0.1, perform a hierarchical overall sorting of the first judgment matrix and the second judgment matrix and perform a consistency check.

[0024] When the third result of the consistency test of the overall hierarchical ranking is greater than or equal to 0.1, the first relative importance and the second relative importance are adjusted, and the first judgment matrix and the second judgment matrix are re-ranked hierarchically. The first judgment matrix and the second judgment matrix are then re-ranked hierarchically until the first result, the second result and the third result are all less than 0.1.

[0025] In some embodiments, the comprehensive performance evaluation of the target layer based on the first score and the judgment matrix includes:

[0026] The second score is evaluated for each of the first type parameters of the criterion layer based on the second judgment matrix and the first score;

[0027] The comprehensive performance evaluation score of the target layer is based on the first judgment matrix and the second score.

[0028] In some embodiments, the dopant type includes inorganic acids; the first type parameter includes the mechanical and physical properties, electrochemical properties, and operational stability of the proton exchange membrane.

[0029] In some embodiments, the relative importance of the electrochemical properties and the mechanophysical properties is 2 to 5;

[0030] The relative importance of the operational stability performance and the mechanical and physical properties is 6 to 9;

[0031] The relative importance of the operational stability and the electrochemical performance is 2 to 7.

[0032] In some embodiments, the second type of parameters corresponding to the mechanical and physical properties include tensile strength, elongation at break, and gel content;

[0033] The second type of parameters corresponding to the electrochemical performance include proton conductivity, inorganic acid doping rate, and volume swelling rate.

[0034] The second type of parameters corresponding to the operational stability performance include oxidative stability, inorganic acid retention rate, and thermal stability.

[0035] In some embodiments, the relative importance of the tensile strength and the elongation at break is 2 to 7;

[0036] The relative importance of the tensile strength and the gel content is 3 to 9;

[0037] The relative importance of the elongation at break and the gel content is 2 to 7.

[0038] In some embodiments, the relative importance of the inorganic acid doping rate and the proton conductivity is 3 to 9;

[0039] The relative importance of the volume swelling ratio and the proton conductivity is 2 to 7;

[0040] The relative importance of the inorganic acid doping rate and the volume swelling rate is 2 to 7.

[0041] In some embodiments, the relative importance of the inorganic acid retention rate and the oxidative stability is 3 to 9;

[0042] The relative importance of the thermal stability and the oxidative stability is 2 to 7;

[0043] The relative importance of the inorganic acid retention rate and the thermal stability is 2 to 7.

[0044] To address the shortcomings of existing methods for evaluating the comprehensive performance of high-temperature proton exchange membrane electrodes, such as a lack of systematization, quantification, objectivity, and efficiency, this invention offers the following advantages:

[0045] This method evaluates the comprehensive performance of membrane electrodes by conducting experiments on proton exchange membranes and analyzing the acquired data. This avoids the problems of long testing cycles and high costs associated with testing proton exchange membranes after fabrication. By acquiring experimental data on multiple influencing factors of the proton exchange membrane's fundamental performance (i.e., multiple second-type parameters), it avoids the problem of insufficient performance evaluation indicators, thus improving the comprehensiveness of the overall performance evaluation. The high-temperature proton exchange membrane electrode comprehensive performance evaluation method, based on hierarchical analysis, employs multi-dimensional indicator considerations and multi-level analysis. This method achieves high quantification and reproducibility in data acquisition and processing, reducing the influence of expert subjective judgment on the overall performance of the membrane electrodes, improving the objectivity and reliability of the evaluation results, and providing a more reliable basis for the application of proton exchange membranes. Furthermore, after establishing the high-temperature proton exchange membrane electrode comprehensive performance evaluation method, the inherent trade-offs between the systematized and quantified performance indicators are clarified. This allows for the precise implementation of R&D decisions when there is room for improvement in one or more performance indicators during subsequent R&D. Attached Figure Description

[0046] Figure 1 A schematic flowchart of a method for evaluating the comprehensive performance of a high-temperature proton exchange membrane electrode is shown in one embodiment. Detailed Implementation

[0047] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0048] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0049] Hydrogen fuel cells, as clean power devices that directly convert hydrogen hydrogen energy into electrical energy, rely heavily on the comprehensive performance of their membrane electrode assembly (MEA), which includes a proton exchange membrane, catalyst layer, and gas diffusion layer, to determine the cell's output power, stability, and lifespan. Among these, high-temperature proton exchange membranes modified with polybenzimidazole (PBI) as the substrate and doped with phosphoric acid (PA) have become a key path to overcome the bottleneck of low-temperature proton exchange membrane applications due to their advantages such as resistance to CO poisoning and simplified thermal management at 120-200℃. However, PA doping presents an inherent contradiction between improving proton conduction efficiency and reducing the stability of PBI molecular chains, as well as the mechanical properties and long-term operational stability of the membrane material. A balance needs to be struck between multiple dimensions of indicators. Existing MEA comprehensive performance evaluation technologies suffer from limitations such as long testing cycles and high costs, single indicators, lack of unified standards for multi-indicator evaluation, reliance on expert subjective judgment, and lack of systematic tools to quantify the trade-offs between indicators. Therefore, developing a systematic, quantitative, objective, and efficient comprehensive performance evaluation method for high-temperature proton exchange membrane electrodes is a critical issue that urgently needs to be addressed to promote the industrialization of high-temperature hydrogen fuel cells.

[0050] To address the shortcomings of existing methods for evaluating the comprehensive performance of high-temperature proton exchange membrane electrodes—namely, their lack of systematization, quantification, objectivity, and efficiency—this invention provides a method for evaluating the comprehensive performance of proton exchange membrane electrodes. Based on the analytic hierarchy process (AHP), such as... Figure 1 As shown, a method for comprehensively evaluating the performance of a proton exchange membrane electrode includes steps S10-S60, which are explained in detail below:

[0051] Step S10: Based on the dopant type of the proton exchange membrane, construct a hierarchical structure model for comprehensive performance evaluation of the membrane electrode. The hierarchical structure model includes a target layer, a criterion layer, and an index layer. The target layer includes the comprehensive performance of the membrane electrode. The criterion layer includes multiple first-type parameters of the proton exchange membrane, which are the main performance indicators of the proton exchange membrane, such as physical and chemical properties. The index layer includes multiple second-type parameters of the proton exchange membrane. Each first-type parameter corresponds to multiple second-type parameters. The second-type parameters are the influencing parameters of the corresponding first-type parameters, and are the basic performance indicators of the proton exchange membrane, such as strength and proton conductivity.

[0052] Step S20: Construct the judgment matrix of the hierarchical structure model; this completes the establishment of the comprehensive performance evaluation method for proton exchange membrane electrodes.

[0053] Step S30: Obtain experimental data for multiple second-type parameters of the index layer corresponding to the proton exchange membrane;

[0054] Step S40: Evaluate the first score for each of the multiple second-type parameters of the indicator layer based on the experimental data;

[0055] Step S50: Evaluate the overall performance of the target layer based on the first score and the judgment matrix; this completes the evaluation of the overall performance of the membrane electrode.

[0056] Step S60: Normalize the overall score. This completes the consistency verification of the comprehensive performance evaluation method for proton exchange membrane electrodes.

[0057] By constructing a hierarchical model based on dopant types, experimental data on multiple second-type parameters of the corresponding index layer of the proton exchange membrane were obtained and analyzed. Based on the hierarchical model, the influence of multiple second-type parameters on the proton exchange membrane electrode was clarified, reducing the evaluation cost of the overall membrane electrode performance and enhancing the evaluation dimensions. This demonstrates how the analytic hierarchy process (AHP) can be used to establish a comprehensive performance evaluation method for high-temperature proton exchange membrane electrodes.

[0058] This method evaluates the comprehensive performance of membrane electrodes by conducting experiments on proton exchange membranes and analyzing the acquired experimental data. This avoids the problems of long testing cycles and high costs associated with testing proton exchange membranes after fabrication. By acquiring experimental data on multiple influencing factors of the proton exchange membrane's fundamental performance (i.e., multiple second-type parameters), it avoids the problem of insufficient performance evaluation indicators for membrane electrodes, thus improving the comprehensiveness of the evaluation. The comprehensive performance evaluation method for proton exchange membrane electrodes, based on hierarchical analysis, employs multi-dimensional indicator considerations and multi-level analysis. This method achieves high quantification and reproducibility in data acquisition and processing, reducing the influence of expert subjective judgment on the comprehensive performance of membrane electrodes and improving the objectivity and reliability of the evaluation results. It also provides a reliable basis for the application of proton exchange membranes. Furthermore, after establishing the comprehensive performance evaluation method for proton exchange membrane electrodes, the inherent trade-offs between the systematized and quantified performance indicators are clarified. This allows for the precise implementation of research and development decisions when there is room for improvement in one or more performance indicators during subsequent research and development.

[0059] Furthermore, step S20 includes steps S21-S22, which are explained in detail below:

[0060] Step S21: Construct a first judgment matrix from the target layer to the criterion layer. The first judgment matrix includes the first relative importance of any two first-type parameters in the criterion layer. This allows the weight ratio of multiple first-type parameters in the criterion layer to be quantified by presetting the first relative importance, and the first judgment matrix is ​​constructed for subsequent data processing. Step S22: Construct a second judgment matrix from the criterion layer to the indicator layer. The second judgment matrix includes the second relative importance of any two second-type parameters in the indicator layer. This allows the weight ratio of multiple second-type parameters in the indicator layer to be quantified by presetting the second relative importance, and the second judgment matrix is ​​constructed for subsequent data processing.

[0061] Furthermore, step S20 also includes steps S23-S26, which are explained in detail below:

[0062] Step S23: Perform hierarchical single sorting and consistency check on the first judgment matrix;

[0063] Step S24: When the first result of the consistency test of the first judgment matrix is ​​greater than or equal to 0.1, adjust the first relative importance in the first judgment matrix, re-rank the first judgment matrix hierarchically and perform a consistency test until the first result is less than 0.1; this allows the consistency test to be passed by adjusting the first relative importance. This indicates that the logic of the first judgment matrix is ​​not obviously contradictory at this point, and the hierarchical single ranking weights calculated based on the first judgment matrix are reliable and can support subsequent comprehensive scoring and decision-making.

[0064] Step S25: Perform hierarchical single sorting and consistency check on the second judgment matrix;

[0065] Step S26: When the second result of the consistency test of the second judgment matrix is ​​greater than or equal to 0.1, adjust the second relative importance in the second judgment matrix, re-rank the second judgment matrix hierarchically and perform a consistency test until the second result is less than 0.1. This allows the consistency test to be passed by adjusting the second relative importance. This indicates that the logic of the second judgment matrix is ​​not obviously contradictory, and the hierarchical single-rank weights calculated based on the second judgment matrix are reliable and can support subsequent comprehensive scoring and decision-making.

[0066] Furthermore, step S20 also includes steps S27-S28, which are explained in detail below:

[0067] Step S27: When both the first result and the second result are less than 0.1, perform a hierarchical overall sorting of the first judgment matrix and the second judgment matrix and perform a consistency check;

[0068] Step S28: When the third result of the consistency test for the overall hierarchical ranking is greater than or equal to 0.1, adjust the first and second relative importance, re-rank the first and second judgment matrices hierarchically, and re-rank the first and second judgment matrices hierarchically until the first, second, and third results are all less than 0.1. This ensures that the consistency test is passed by adjusting the first and second relative importance. This indicates that there is no obvious logical contradiction between the first and second judgment matrices, and the overall hierarchical ranking weights calculated based on the first and second judgment matrices are reliable and can support subsequent comprehensive scoring and decision-making, completing the construction of the judgment matrix for the entire hierarchical structure model.

[0069] Further, step S50 includes steps S51-S52:

[0070] Step S51: Evaluate the second score for each of the multiple first-type parameters of the criterion layer based on the second judgment matrix and the first score;

[0071] Step S52: Evaluate the overall performance of the target layer based on the first judgment matrix and the second score. This allows for a step-by-step evaluation of the overall performance of the membrane electrode.

[0072] Furthermore, the dopant type includes inorganic acids, preferably phosphoric acid; the first type of parameters includes the mechanical and physical properties, electrochemical properties, and operational stability of the proton exchange membrane. This embodiment, by defining mechanical and physical properties as one of the performance criteria of the criterion layer, can serve as an evaluation standard for the degree of inorganic acid doping, thereby precisely controlling the inorganic acid doping rate in the proton exchange membrane and effectively avoiding the significant impact of inorganic acid doping on the mechanical and physical properties of the membrane electrode. This embodiment, by defining electrochemical properties as one of the performance criteria of the criterion layer, can evaluate the efficiency and rate of proton transfer within the proton exchange membrane itself, thus directly relating to the performance of the hydrogen fuel cell. This embodiment, by defining operational stability as one of the performance criteria of the criterion layer, can assess to some extent the degree of inorganic acid loss from the membrane electrode and the degree of catalyst poisoning, thus directly relating to the output power and power generation efficiency of the hydrogen fuel cell. Therefore, mechanical and physical properties, electrochemical properties, and operational stability—these three main performance indicators—can provide clear, accurate, comprehensive, objective, and quantitative basis for the research and development decisions on inorganic acid doping, thereby accelerating the development and application of new materials.

[0073] Furthermore, as shown in Table 1:

[0074] Table 1—Judgment Matrix from Target Layer to Criterion Layer

[0075]

[0076] The relative importance of electrochemical performance and mechanophysical performance (A)12 The value is 2 to 5, preferably 3;

[0077] The relative importance of operational stability and mechanical-physical properties (A) 13 The value is 6 to 9, preferably 7;

[0078] The relative importance of operational stability and electrochemical performance (A) 23 The value is 2 to 7, preferably 5;

[0079] Table 1, A ij With A ji They are reciprocals of each other, and both i and j are positive integers.

[0080] The proton exchange membrane based on PBI inherently possesses good mechanical and physical properties. The decline in these properties is due to the doping of inorganic acids, which is not a key factor affecting the overall performance of the membrane electrode. Therefore, the mechanical and physical properties in the criterion layer are given the lowest weight. Although electrochemical performance is a key indicator for evaluating membrane electrode performance, it largely depends on the amount of inorganic acid doping. Therefore, electrochemical performance is given a moderate weight. Compared to low-temperature proton exchange membranes, high-temperature proton exchange membranes also experience inorganic acid loss. This loss leads to poorer operational stability of high-temperature proton exchange membranes. Therefore, operational stability is a key factor in evaluating the overall performance of the membrane electrode, and is given the highest weight.

[0081] Furthermore, the second type of parameters corresponding to the mechanical and physical properties include tensile strength, elongation at break, and gel content;

[0082] The proton exchange membrane sample was cut into dumbbell-shaped sample strips, placed in the test room until it reached room temperature, and then subjected to uniaxial tensile testing using a universal tensile testing machine at a tensile rate of 5 mm / min. The highest stress was recorded as the tensile strength.

[0083] The proton exchange membrane sample was cut into dumbbell-shaped sample strips, placed in the test room until it reached room temperature, and then subjected to uniaxial tensile testing using a universal tensile testing machine at a tensile rate of 5 mm / min. The fracture strain was recorded as the elongation at break.

[0084] Take a regularly shaped proton exchange membrane sample, weigh it, and record the initial mass as W0. Then, place the PBI membrane sample in a glass bottle and soak it in dimethyl sulfoxide (DMSO) at 80°C for 200 hours. Afterward, transfer the PBI membrane sample to ethanol and soak it for 1 hour to remove the solvent. Finally, place the PBI membrane sample in a vacuum oven at 120°C for 24 hours and record the weight as W1. The gel content of the proton exchange membrane is determined by... This indicates that the following formula should be used to calculate and record the results;

[0085]

[0086] The mechanical and physical properties of proton exchange membranes can be evaluated by obtaining experimental data on tensile strength, elongation at break, and gel content and assessing the first score.

[0087] The second type of parameters corresponding to electrochemical performance include proton conductivity, inorganic acid doping rate, and volume swelling rate;

[0088] Proton conductivity: The resistance of the proton exchange membrane (PEM) was tested using a four-probe method. The PEM was cut to a standard size and placed in a fixture with four parallel electrodes, typically made of platinum or stainless steel, ensuring good contact between the electrodes and the membrane surface. The two outer electrodes are current electrodes, used to apply an AC signal, while the two inner electrodes are voltage electrodes, used to detect the voltage drop. The entire fixture and the PEM sample were placed in an environmental chamber at 160°C and 0%RH (Relative Humidity) for 30-60 minutes. Impedance scanning was performed within the range of 1Hz-1MHz, with a small AC disturbance voltage applied to avoid damaging the PEM. The PEM resistance R was obtained from the measured impedance data and calculated using the following formula:

[0089]

[0090] L: Distance between the two electrodes (cm);

[0091] R: Measured film resistance (Ω);

[0092] S: Cross-sectional area of ​​the proton exchange membrane (cm²) 2 );

[0093] Proton conductivity (S / cm).

[0094] Inorganic acid doping rate: The PBI membrane was cut into regular shapes and weighed to obtain its original mass (W1). Then, the PBI membrane sample was placed in an 85wt% inorganic acid solution and immersed at 120℃ for different times. After removing the proton exchange membrane sample, the inorganic acid on its surface was wiped dry. Finally, the proton exchange membrane sample was placed in a 120℃ oven to remove moisture, and its weight at this point was measured (W3). The inorganic acid doping rate was calculated using the following formula, denoted by n:

[0095]

[0096] Swelling rate after inorganic acid doping: The PBI membrane was cut into a regular shape, and its length, width, and thickness were measured to obtain its original volume (V1). The PBI membrane sample was then immersed in an 85 wt% inorganic acid solution at 120°C for different times. After removing the PBI / PA sample membrane, the inorganic acid on its surface was wiped dry, and the length, width, and thickness of the PBI / PA membrane were measured to obtain its swollen volume (V2). The proton exchange membrane volume swelling rate was calculated using the following formula and... express:

[0097]

[0098] By obtaining experimental data on the proton conductivity, inorganic acid doping rate, and volume swelling rate of the proton exchange membrane and evaluating the first score, the electrochemical performance of the proton exchange membrane can be assessed.

[0099] The second type of parameters corresponding to operational stability performance include oxidative stability, inorganic acid retention rate, and thermal stability.

[0100] Oxidative stability: PBI membrane samples were cut into regular shapes and weighed, then placed in prepared Fenton's reagent and kept at 80°C for 24 hours. After the test, the membrane samples were removed, the membrane surface was washed with deionized water and wiped clean, then dried in a 120°C oven for 12 hours and weighed again. This procedure was repeated at least five times, with each test using freshly prepared Fenton's reagent. The antioxidant stability of the PBI samples was evaluated by the ratio of the remaining mass to the original mass.

[0101] Inorganic acid retention rate: The PBI membrane was cut into regular shapes and weighed (W1). Then, the membrane was immersed in an 85wt% inorganic acid solution at 120℃ for different times. The PBI / PA samples were then removed and weighed (W2). Finally, the PBI / PA membrane samples were placed in a constant temperature and humidity chamber at 80℃ and 40%RH for 60 hours. After that, the membrane was removed, the inorganic acid and moisture on the surface were wiped off, and the membrane was weighed (W3). The inorganic acid retention rate was calculated using... It is expressed and calculated according to the following formula:

[0102]

[0103] Thermal stability: Thermogravimetric analysis (TGA) was used to assess thermal stability. PBI samples were placed in a constant-temperature drying oven and dried at 150°C for 24 hours to thoroughly remove adsorbed moisture and volatile impurities. 5-10 mg of PBI sample was weighed for testing. Under a nitrogen atmosphere (flow rate 50 mL / min), the temperature was programmed to rise from room temperature to 800°C at a linear rate of 20°C / min. The percentage of remaining weight of the PBI sample at 800°C was recorded as the thermal stability index using the thermogravimetric curve.

[0104] By acquiring experimental data on the oxidative stability, inorganic acid retention rate, and thermal stability of the proton exchange membrane and evaluating the first score, the operational stability of the proton exchange membrane electrode can be assessed. Thus, a comprehensive performance evaluation method for high-temperature proton exchange membrane electrodes is established using the settings of the second type of parameters mentioned above in the analytic hierarchy process.

[0105] Furthermore, as shown in Table 2:

[0106] Table 2—Judgment Matrix from Mechanical and Physical Properties in the Criterion Layer to Corresponding Indicator Layers

[0107]

[0108] The relative importance of tensile strength and elongation at break (B) 12 The value is 2 to 7, preferably 5;

[0109] The relative importance of tensile strength and gel content (B) 13 The value is 3 to 9, preferably 7;

[0110] The relative importance of elongation at break and gel content (B) 23 The value is 2 to 7, preferably 3;

[0111] Table 2, B ij With B ji They are reciprocals of each other, and both i and j are positive integers.

[0112] Tensile strength and elongation at break are the basic indicators for evaluating the compressive and tensile stress resistance of proton exchange membranes. The performance of tensile strength and elongation at break will decrease after inorganic acid doping. Therefore, tensile strength is set as the highest weight in the index layer corresponding to mechanical and physical properties, and elongation at break is set as a general weight in the index layer corresponding to mechanical and physical properties. Gel content is an indicator for evaluating the degree of entanglement and cross-linking of polymer molecular chains in proton exchange membranes. Therefore, gel content is set as the lowest weight in the index layer corresponding to mechanical and physical properties.

[0113] Furthermore, as shown in Table 3:

[0114] Table 3—Judgment Matrix from Electrochemical Performance in Criterion Layer to Corresponding Index Layer

[0115]

[0116] The relative importance of inorganic acid doping rate and proton conductivity C 12 The value is 3 to 9, preferably 5;

[0117] The relative importance of volume swelling ratio and proton conductivity C 13 The value is 2 to 7, preferably 3;

[0118] The relative importance of inorganic acid doping rate and volume swelling rate C 23 The value is 2 to 7, preferably 3;

[0119] C in Table 3 ij With C ji They are reciprocals of each other, and both i and j are positive integers.

[0120] Proton conductivity is a key indicator for evaluating the performance of proton exchange membranes (PEMs). However, proton conductivity is typically tested under low pressure using the four-probe method. During the fabrication of the membrane electrode assembly (MEA), the PEM needs to withstand the assembly pressure of the electrode stack, which disrupts the inorganic acid transport channels within the PEM and reduces the proton conductivity of the MEA. Therefore, proton conductivity lacks accuracy in evaluating MEA performance. Thus, proton conductivity is set as the lowest weight in the electrochemical performance indicator layer. Inorganic acid doping rate can, to some extent, directly reflect the proton conductivity of the PEM, as well as the possibility of inorganic acid loss and the stability of the PEM after adsorbing inorganic acids. Therefore, it is set as the highest weight in the electrochemical performance indicator layer. The volume swelling rate after inorganic acid doping can be used to evaluate the change in the physical structural stability of the PEM after adsorbing inorganic acids and the proton conductivity after assembly. Therefore, it is set as a general weight in the electrochemical performance indicator layer.

[0121] Furthermore, as shown in Table 4:

[0122] Table 4—Judgment Matrix from Operational Stability Performance in the Criterion Layer to Corresponding Indicator Layer

[0123]

[0124] The relative importance of inorganic acid retention rate and oxidative stability (D) 12 The value is 3 to 9, preferably 7;

[0125] The relative importance of thermal stability and oxidative stability (D) 13 The value is 2 to 7, preferably 3;

[0126] The relative importance of inorganic acid retention rate and thermal stability (D) 23The value is 2 to 7, preferably 5;

[0127] D in Table 4 ij With D ji They are reciprocals of each other, and both i and j are positive integers.

[0128] Oxidative stability is a fundamental indicator of PBI membranes as proton exchange membranes, representing a basic property inherent in the PBI material itself. Proton exchange membranes of the same type made with PBI as the substrate exhibit very little difference in oxidative stability; therefore, oxidative stability is set as the lowest weight in the indicator layer corresponding to operational stability. The retention rate of inorganic acids in proton exchange membranes largely determines the operational stability of the membrane electrode performance; therefore, the inorganic acid retention rate is set as the highest weight in the indicator layer corresponding to operational stability. Thermal stability is also a fundamental indicator of PBI membranes as proton exchange membranes. Since modification of proton exchange membranes typically leads to a decrease in thermal stability, thermal stability is set as a general weight in the indicator layer corresponding to operational stability.

[0129] The evaluation system was validated using the performance of the high-temperature proton exchange membrane electrode in a case study. The comprehensive performance scores of the high-temperature proton exchange membrane electrode application case are shown in Table 5.

[0130] Table 5—Comprehensive Performance Score of High-Temperature Proton Exchange Membrane Electrode Performance Application Case Evaluation

[0131]

[0132] The power density of the membrane electrode after 1000 hours of operation was estimated using the power density and voltage decay rate of the membrane electrode from the literature as verification data. The comprehensive performance score of the high-temperature proton exchange membrane electrode application case is shown in Table 6.

[0133] Table 6—Comprehensive Performance Score of High-Temperature Proton Exchange Membrane Electrode Performance Application Case Verification

[0134]

[0135] Therefore, the normalized scores of the comprehensive performance of Case 1 to Case 4 are ranked in the same order in Tables 5 and 6, decreasing sequentially from Case 1 to Case 4, thus verifying that the evaluation system built by the proton exchange membrane electrode method in this embodiment is objective and accurate.

[0136] In summary, this invention establishes the relationship between the performance indicators of high-temperature proton exchange membranes (PTMs) and the comprehensive performance of membrane electrodes using the analytic hierarchy process (AHP). It establishes a high-temperature PTM / membrane electrode evaluation model, reducing the testing costs and development cycle of traditional membrane electrode performance evaluations. By comprehensively evaluating the multi-dimensional performance of high-temperature PTMs, it assesses the comprehensive performance of membrane electrodes through quantitative and standardized evaluation methods. This invention offers the following technical advantages: First, by analyzing the underlying reasons and logic of the physicomechanical, electrochemical, and operational stability performance of high-temperature PTMs, and combining the correspondence between high-temperature PTM indicator testing methods and comprehensive membrane electrode performance, it assigns weights to the criterion and indicator layers, establishing an evaluation system from high-temperature PTM performance to comprehensive membrane electrode performance. Second, by evaluating the comprehensive performance of membrane electrodes based on the performance of the high-temperature PTM, it reduces the testing time and cost of membrane electrode performance degradation, thereby lowering the development cost and shortening the development cycle of high-temperature PTMs. Third, by establishing an evaluation system for the comprehensive performance of high-temperature PTM / membrane electrodes from multiple performance indicators, it avoids problems such as the simplification of evaluation indicators and incomplete evaluation criteria, which affect the accuracy of the evaluation. Fourthly, we will establish the inherent trade-off between the performance of high-temperature proton exchange membranes and the overall performance of membrane electrodes, and provide a systematic tool to quantify these weights, thus providing a clear and quantitative basis for R&D decisions.

[0137] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. A method for comprehensively evaluating the performance of high-temperature proton exchange membrane electrodes, characterized in that, The comprehensive performance evaluation method for high-temperature proton exchange membrane electrodes includes: Based on the dopant type of the proton exchange membrane, a hierarchical structure model for evaluating the comprehensive performance of the membrane electrode is constructed. The hierarchical structure model includes a target layer, a criterion layer, and an index layer. The target layer includes the comprehensive performance of the membrane electrode. The criterion layer includes multiple first-type parameters of the proton exchange membrane. The index layer includes multiple second-type parameters of the proton exchange membrane. Each first-type parameter corresponds to multiple second-type parameters. The second-type parameters are the influencing parameters of the corresponding first-type parameters. Construct the judgment matrix of the hierarchical structure model; Experimental data were obtained for multiple second-type parameters corresponding to the index layer of the proton exchange membrane. Based on the experimental data, a first score is evaluated for each of the second type parameters of the indicator layer; The comprehensive performance evaluation score of the target layer is based on the first score and the judgment matrix. The comprehensive score is then normalized.

2. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 1, characterized in that, The judgment matrix for constructing the hierarchical structure model includes: Construct a first judgment matrix from the target layer to the criterion layer; the first judgment matrix includes the first relative importance of any two first type parameters of the criterion layer; Construct a second judgment matrix from the criterion layer to the indicator layer; the second judgment matrix includes the second relative importance of any two second type parameters of the indicator layer.

3. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 2, characterized in that, The judgment matrix for constructing the hierarchical structure model also includes: The first judgment matrix is ​​sorted hierarchically and a consistency check is performed. When the first result of the consistency test of the first judgment matrix is ​​greater than or equal to 0.1, the first relative importance in the first judgment matrix is ​​adjusted, the first judgment matrix is ​​re-sorted hierarchically and a consistency test is performed until the first result is less than 0.

1. The second judgment matrix is ​​sorted hierarchically and a consistency check is performed. If the second result of the consistency test of the second judgment matrix is ​​greater than or equal to 0.1, adjust the second relative importance in the second judgment matrix, re-sort the second judgment matrix hierarchically and perform a consistency test until the second result is less than 0.

1.

4. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 3, characterized in that, The judgment matrix for constructing the hierarchical structure model also includes: When both the first result and the second result are less than 0.1, perform a hierarchical overall sorting of the first judgment matrix and the second judgment matrix and perform a consistency check. When the third result of the consistency test of the overall hierarchical ranking is greater than or equal to 0.1, the first relative importance and the second relative importance are adjusted, and the first judgment matrix and the second judgment matrix are re-ranked hierarchically. The first judgment matrix and the second judgment matrix are then re-ranked hierarchically until the first result, the second result and the third result are all less than 0.

1.

5. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 2, characterized in that, The comprehensive performance evaluation of the target layer based on the first score and the judgment matrix includes: The second score is evaluated for each of the first type parameters of the criterion layer based on the second judgment matrix and the first score; The comprehensive performance evaluation score of the target layer is based on the first judgment matrix and the second score.

6. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 2, characterized in that, The dopant type includes inorganic acids; the first type parameters include the mechanical and physical properties, electrochemical properties, and operational stability of the proton exchange membrane.

7. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 6, characterized in that, The relative importance of the electrochemical properties and the mechanophysical properties is 2 to 5; The relative importance of the operational stability performance and the mechanical and physical properties is 6 to 9; The relative importance of the operational stability and the electrochemical performance is 2 to 7.

8. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrode according to claim 6, characterized in that, The second type of parameters corresponding to the mechanical and physical properties include tensile strength, elongation at break, and gel content; The second type of parameters corresponding to the electrochemical performance include proton conductivity, inorganic acid doping rate, and volume swelling rate. The second type of parameters corresponding to the operational stability performance include oxidative stability, inorganic acid retention rate, and thermal stability.

9. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 8, characterized in that, The relative importance of the tensile strength and the elongation at break is 2 to 7; The relative importance of the tensile strength and the gel content is 3 to 9; The relative importance of the elongation at break and the gel content is 2 to 7.

10. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrode according to claim 8, characterized in that, The relative importance of the inorganic acid doping rate and the proton conductivity is 3 to 9; The relative importance of the volume swelling ratio and the proton conductivity is 2 to 7; The relative importance of the inorganic acid doping rate and the volume swelling rate is 2 to 7.

11. The method for comprehensive performance evaluation of high-temperature proton exchange membrane electrodes according to claim 8, characterized in that, The relative importance of the inorganic acid retention rate and the oxidation stability is 3 to 9; The relative importance of the thermal stability and the oxidative stability is 2 to 7; The relative importance of the inorganic acid retention rate and the thermal stability is 2 to 7.

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