High-performance binder-free nanofiber membrane electrode, preparation method thereof and fuel cell

Abstract

The invention discloses a high-performance binder-free nanofiber membrane electrode, a preparation method thereof and a fuel cell, and belongs to the technical field of fuel cells. The preparation method provided by the invention comprises the following steps: carrying out constant potential treatment on a single cell assembled by a nanofiber membrane electrode under the conditions that air is introduced into a cathode and hydrogen is introduced into an anode, and after the treatment is completed, purging for a set time under the conditions that nitrogen is introduced into the cathode and hydrogen is introduced into the anode; and then carrying out cyclic voltammetry scanning under the condition that nitrogen is introduced into a cathode and hydrogen is introduced into an anode, so as to obtain the high-performance binder-free nanofiber membrane electrode. Wherein the cathode catalyst layer of the nanofiber membrane electrode is prepared by an electrostatic spinning method. According to the preparation method provided by the invention, the binder in the nanofiber membrane electrode can be effectively removed, the utilization rate and catalytic activity of the catalyst and the working performance of the membrane electrode are remarkably improved, and the preparation method is simple and easy to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a high-performance binder-free nanofiber membrane electrode and a preparation method thereof, and a fuel cell. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance understanding of the overall background of the invention and is not necessarily regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Fuel cells, especially hydrogen fuel cells, are considered a key technology for promoting energy transformation and achieving sustainable development due to their significant advantages such as high energy density and zero pollution emissions. They have received widespread attention worldwide in recent years. However, the large-scale application of fuel cells currently still faces significant bottlenecks. The most prominent challenge is the high cost. Pt-based catalysts, as core components, account for a large proportion of the total battery cost due to resource scarcity and complex preparation processes. This greatly limits the commercialization of fuel cells. Therefore, how to effectively improve the utilization rate of Pt-based catalysts and reduce the amount of Pt required per unit energy output has become one of the core research topics in this field.

[0004] In this context, constructing ordered membrane electrodes is recognized as an effective strategy to reduce Pt usage, and electrospinning technology has become a common method for constructing such membrane electrodes due to its ability to efficiently prepare ordered nanofiber structures. However, in practical applications, it has been found that nanofiber electrodes prepared by traditional electrospinning processes generally have the problem of the active sites of the catalyst being wrapped by the binder. While the binder fixes the nanofiber structure, it partially covers or even wraps the catalyst particles, resulting in a large number of active sites being unable to fully contact the reaction gas. Ultimately, the actual utilization rate of the catalyst is far lower than the theoretical value. This defect seriously restricts the further improvement of the performance of ordered membrane electrodes. Summary of the Invention

[0005] In view of this, the present invention provides a high-performance binder-free nanofiber membrane electrode and its preparation method, and a fuel cell. The present invention can provide a binder-free nanofiber electrode, the active sites of the catalyst are effectively exposed, and the catalyst utilization rate can be significantly improved, thereby improving the performance of the nanofiber membrane electrode.

[0006] In a first aspect, the present invention provides a method for preparing a high-performance binder-free nanofiber membrane electrode, comprising the following steps: The single cell assembled with the nanofiber membrane electrode was subjected to a constant potential treatment under the conditions of air flowing through the cathode and hydrogen flowing through the anode. After the treatment, nitrogen was passed through the cathode and hydrogen was passed through the anode for a set time. Cyclic voltammetry was then performed under the conditions of nitrogen flowing through the cathode and hydrogen flowing through the anode to obtain a high-performance binder-free nanofiber membrane electrode. Wherein, the cathode catalyst layer of the nanofiber membrane electrode is prepared by electrostatic spinning.

[0007] Preferably, the preparation method of the nanofiber membrane electrode is as follows: A nanofiber catalyst layer is prepared by electrospinning and transferred to one side of a proton exchange membrane to obtain a cathode catalyst layer; an anode slurry is sprayed on the other side of the proton exchange membrane to prepare an anode catalyst layer, thereby constructing a catalyst-coated membrane; alternatively, an anode catalyst layer and a cathode catalyst layer are prepared by electrospinning and transferred to both sides of the proton exchange membrane to construct a catalyst-coated membrane; The catalyst coating membrane and the gas diffusion layer are hot pressed to form a nanofiber membrane electrode.

[0008] Furthermore, the catalysts of the anode catalyst layer and the cathode catalyst layer are independently selected from one or more of platinum-carbon catalysts, platinum-based alloy catalysts or non-precious metal catalysts.

[0009] Preferably, the potential of the constant potential treatment is 0.2~0.4V.

[0010] Preferably, the constant potential treatment time is 40 to 80 minutes.

[0011] Preferably, after the constant potential treatment is completed, nitrogen is passed through the cathode and hydrogen is passed through the anode for 15 to 40 minutes.

[0012] Preferably, the potential interval of the cyclic voltammetry scan is 0-1.2V.

[0013] Preferably, the number of scanning cycles of the cyclic voltammetry scan is 15 to 30 cycles.

[0014] In a second aspect, the present invention provides a high-performance binder-free nanofiber membrane electrode prepared by the above preparation method.

[0015] In a third aspect, the present invention provides a fuel cell comprising the above-mentioned high-performance binder-free nanofiber membrane electrode.

[0016] Compared with the prior art, the present invention has achieved the following beneficial effects: The present invention effectively removes the binder from the nanofiber membrane electrode by subjecting the assembled single cell to a three-step process: constant potential treatment, purging, and cyclic voltammetry scanning. This reduces the physical coverage of the binder on the catalyst active sites, significantly improving catalyst utilization and catalytic activity, and enhancing the membrane electrode's performance. The preparation method provided by the present invention is simple and easy to operate, enabling rapid production of high-performance, binder-free nanofiber membrane electrodes. The treated membrane electrode exhibits superior electrochemical performance compared to the original membrane electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute undue limitations thereon. It is obvious that one of ordinary skill in the art could derive other drawings based on these drawings without inventive effort.

[0018] Figure 1 This is a scanning electron microscope image of the cathode catalyst layer of the nanofiber membrane electrode of Comparative Example 1 of the present invention; Figure 2 This is a scanning electron microscope image of the cathode catalyst layer of the nanofiber membrane electrode of Example 1 of the present invention; Figure 3 1 is the BET curve of Example 1 of the present invention and Comparative Example 1; Figure 4 1 and 2 are polarization curves of Example 1, Example 2, and Comparative Examples 1 to 4 of the present invention; Figure 5 CV curves of Example 1 and Comparative Example 1 of the present invention; Figure 6 1 and 2 are polarization curves of Example 1 of the present invention and Comparative Example 1 after the first cycle and 30,000 cycles of CV aging. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0020] Explanation of terms: Constant potential treatment is a technique for maintaining a constant electrode potential to conduct electrochemical reactions. Its core approach involves using a potentiostat and other equipment to regulate the output current through feedback, stabilizing the electrode potential at a preset value and preventing potential fluctuations from affecting the reaction process. Constant potential treatment ensures that the electrode reaction proceeds continuously at a specific potential. In this application, constant potential treatment is used to generate water and remove binders at high current densities.

[0021] Cyclic voltammetry (CV) scan: A triangular waveform potential scan is applied to the working electrode (linearly scan from the initial potential to the peak potential and then reversely scan back to the initial potential) to record the change in current versus potential (also known as a "cyclic voltammogram" or "CV curve").

[0022] Catalyst coated membrane (CCM): Catalyst coated membrane is a catalytic layer structure formed by coating catalyst on both sides of the proton exchange membrane. It is the core part of the membrane electrode assembly (MEA).

[0023] Gas Diffusion Layer (GDL): A gas diffusion layer (GDL) is a porous material layer located between the bipolar plate and the catalyst layer in a fuel cell. It typically consists of a base layer and a microporous layer. The base layer is made of materials such as carbon fiber paper and carbon cloth, while the microporous layer is a mixture of carbon powder and a hydrophobic agent. Its core functions include: ① supporting the catalyst layer and stabilizing the electrode structure; ② conducting the reaction gases to the catalyst layer surface; ③ collecting electrons generated by the catalyst layer and conducting them to the external circuit; and ④ draining away water generated by the reaction to prevent "water flooding" of the electrode and thus degrading performance.

[0024] Nanofiber membrane electrode: a type of membrane electrode assembly (MEA) with nanofiber material as the core skeleton or carrier of the catalytic layer.

[0025] The present invention provides a method for preparing a high-performance binder-free nanofiber membrane electrode, comprising the following steps: The single cell assembled with the nanofiber membrane electrode was subjected to a constant potential treatment under the conditions of air flowing through the cathode and hydrogen flowing through the anode. After the treatment, nitrogen was passed through the cathode and hydrogen was passed through the anode for a set time. Cyclic voltammetry was then performed under the conditions of nitrogen flowing through the cathode and hydrogen flowing through the anode to obtain a high-performance binder-free nanofiber membrane electrode. Wherein, the cathode catalyst layer of the nanofiber membrane electrode is prepared by electrostatic spinning.

[0026] This invention effectively removes the binder from the nanofiber electrode through a specific treatment process, significantly improving catalyst utilization and electrode performance. First, during the constant potential treatment under H2 / air conditions, water generated at the cathode dissolves the binder (such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid) in the electrode, reducing the physical coverage of the binder on the catalyst's active sites, allowing more catalyst to directly participate in the electrochemical reaction and fundamentally improving the effective catalyst utilization. Second, the H2 / N2 purge step promptly removes the water that dissolves the binder, preventing the problem of catalyst "flooding" caused by residual moisture, maintaining the unobstructed gas transfer channels within the electrode, and optimizing the transport efficiency of the reactant gases (hydrogen and oxygen). Finally, the cyclic voltammetry scan treatment, through periodic changes in the potential range, further strips away the outer layer of catalyst that has become ineffective due to initial flooding, fully exposing the highly active inner layer of catalyst that was not covered. This comprehensively improves the electrode's catalytic activity and stability, ultimately resulting in a high-performance binder-free nanofiber membrane electrode.

[0027] In the present invention, the preparation method of the nanofiber membrane electrode is as follows: A nanofiber catalyst layer is prepared by electrospinning and transferred to one side of a proton exchange membrane to obtain a cathode catalyst layer; an anode slurry is sprayed on the other side of the proton exchange membrane to prepare an anode catalyst layer, thereby constructing a catalyst-coated membrane; alternatively, an anode catalyst layer and a cathode catalyst layer are prepared by electrospinning and transferred to both sides of the proton exchange membrane to construct a catalyst-coated membrane; The catalyst coating membrane and the gas diffusion layer are hot pressed to form a nanofiber membrane electrode.

[0028] The present invention does not impose any special restrictions on the specific preparation method of the nanofiber membrane electrode. For example, the formula and preparation method of the anode slurry, the formula and preparation method of the cathode spinning slurry, the transfer method, the selection of the proton exchange membrane, the parameters of the hot pressing molding, etc. can all be prepared using the conventional nanofiber membrane electrode methods in the field.

[0029] The present invention does not impose any special restrictions on the method of assembling the nanofiber membrane electrode into a single cell, and the commonly used method of assembling a single cell in the art can be used.

[0030] In the present invention, the catalysts of the anode catalyst layer and the cathode catalyst layer are independently selected from one or more of a platinum-carbon catalyst, a platinum-based alloy catalyst, or a non-precious metal catalyst. The present invention does not impose any particular restrictions on the source and preparation method of the specific catalyst.

[0031] In the present invention, the potential for the constant potential treatment is 0.2-0.4V. This potential range ensures a sufficiently high reaction current density. The water generated by the electrochemical reaction (O₂ + H₂ → 2H₂O) effectively dissolves the binder in the electrode, stripping it from the catalyst surface and releasing the covered active sites. The constant potential treatment lasts for 40-80 minutes, preferably 50-70 minutes, to ensure sufficient dissolution of the binder and prevent the electrode structure from swelling or shedding due to prolonged water immersion, which could affect the mechanical stability of the catalyst layer.

[0032] In the present invention, after the constant potential treatment is completed, nitrogen is passed through the cathode and hydrogen is passed through the anode for a purge period of 15 to 40 minutes. For example, 15 minutes, 20 minutes, 25 minutes, 30 minutes, or 40 minutes can be selected. After the constant potential treatment, moisture that dissolves the binder remains on the electrode surface and in the pores. If this moisture is not removed promptly, it may cause "flooding" of the catalyst (i.e., pores filled with water, hindering the transmission of the reactant gases) or residual binder to redeposit on the catalyst surface. Purging under H2 / N2 conditions quickly removes moisture from the electrode surface and interior, as well as the binder dissolved in water, restoring the unobstructed gas diffusion path.

[0033] In the present invention, the potential range of the cyclic voltammetry scan is 0-1.2 V. The lower limit of the potential range is close to the hydrogen evolution potential, and small molecular impurities remaining on the catalyst surface can be cleaned through H2 adsorption / desorption reactions. The upper limit of the potential range can remove the outer layer of the catalyst that has become ineffective due to early water flooding or binder residue through oxidation reactions, exposing the uncovered high-activity catalyst in the inner layer.

[0034] In the present invention, the number of cyclic voltammetry scans is 15 to 30, more preferably 18 to 25. A sufficient number of scans ensures that the failed outer layer is fully exfoliated and the active sites are fully exposed; however, excessive scans may cause catalyst particles to agglomerate or fall off, reducing electrode life.

[0035] In the present invention, the purity of nitrogen and hydrogen introduced into the cathode and anode is above 99.99%.

[0036] The present invention also provides a high-performance binder-free nanofiber membrane electrode prepared by the above preparation method.

[0037] The present invention also provides a fuel cell comprising the high-performance binder-free nanofiber membrane electrode. The present invention does not impose any particular restrictions on the specific preparation method of the fuel cell, and the preparation method of the fuel cell commonly used in the art can be used.

[0038] The technical solution of the present invention is further described below with reference to specific embodiments. In the following embodiments, the purity of hydrogen and nitrogen is above 99.99%.

[0039] Example 1 This embodiment provides a high-performance binder-free nanofiber membrane electrode and a preparation method thereof.

[0040] The specific preparation method is as follows: (1) Preparation of cathode spinning slurry: Accurately weigh 1.5 g of Pt / C catalyst (Pt content is 60 wt%), add 4.2 g of 10 wt% Nafion, 7.4 g of isopropanol, and 11.8 g of deionized water, crush the cells for 10 min, shear for 20 min, and ultrasonicate for 40 min to mix them evenly. Take 8.3 g of the mixed solution and add 0.12 g of PAA. Stir for 24 h to obtain cathode spinning slurry.

[0041] (2) Preparation of cathode catalyst layer: The temperature was controlled below 30°C, the humidity was controlled below 50%, the positive high voltage was 14 kV, the negative high voltage was -2 kV, and the liquid flow rate was 0.2 mm / min. The cathode spinning slurry prepared in step (1) was electrospun for 5 h to obtain a nanofiber catalyst layer. The nanofiber catalyst layer was transferred to a proton exchange membrane at 150°C and 0.3 MPa to obtain a cathode catalyst layer.

[0042] (4) Preparation of anode slurry: Take 0.23 g of Pt / C catalyst (Pt content is 60 wt%), add 1.6 g of deionized water, 0.645 g of 10 wt% Nafion and 30.2 g of ethanol in sequence, crush the cells for 45 min, and ultrasonicate for 30 min to obtain the spray slurry.

[0043] (5) Spraying the anode slurry onto the other side of the proton exchange membrane in step (2) to obtain an anode catalyst layer, that is, constructing a catalyst-coated membrane.

[0044] (6) The catalyst-coated membrane, gas diffusion layer, and frame material of step (5) are hot-pressed to prepare a nanofiber membrane electrode, which is then assembled together with a bipolar plate and a seal to form a single cell.

[0045] (7) The single cell obtained in step (6) was subjected to a 0.3 V constant potential treatment for 1 h with air flowing through the cathode and hydrogen flowing through the anode.

[0046] (8) Turn off the load and then purge for 20 min with nitrogen flowing through the cathode and hydrogen flowing through the anode.

[0047] (9) Then, under the conditions of nitrogen flowing through the cathode and hydrogen flowing through the anode, cyclic voltammetry scans were performed between 0 and 1.2 V for 20 cycles to obtain a high-performance binder-free nanofiber membrane electrode.

[0048] Example 2 This embodiment provides a high-performance binder-free nanofiber membrane electrode and a preparation method thereof.

[0049] The specific preparation method is as follows: (1) Preparation of cathode spinning slurry: Accurately weigh 1.5 g of Pt / C catalyst (Pt content is 60 wt%), add 4.2 g of 10 wt% Nafion, 7.4 g of isopropanol, and 11.8 g of deionized water, crush the cells for 10 min, shear for 20 min, and ultrasonicate for 40 min to mix them evenly. Take 8.3 g of the mixed solution and add 0.12 g of PAA. Stir for 24 h to obtain cathode spinning slurry.

[0050] (2) Preparation of cathode catalyst layer: The temperature was controlled below 30°C, the humidity was controlled below 50%, the positive high voltage was 14 kV, the negative high voltage was -2 kV, and the liquid flow rate was 0.2 mm / min. The cathode spinning slurry prepared in step (1) was used for electrospinning for 5 h to obtain a nanofiber catalyst layer. At 150°C and 0.3 MPa, the nanofiber catalyst layer was transferred to one side of the proton exchange membrane to obtain a cathode catalyst layer.

[0051] (3) Preparation of anode spinning slurry: Accurately weigh 1.5 g of Pt / C catalyst (Pt content is 60 wt%), add 4.2 g of 10 wt% Nafion, 7.4 g of isopropanol, and 11.8 g of deionized water, crush the cells for 10 min, shear for 20 min, and ultrasonicate for 40 min to mix them evenly. Take 8.3 g of the mixed solution and add 0.12 g of PAA. Stir for 24 h to obtain cathode spinning slurry.

[0052] (4) The temperature was controlled to be lower than 30°C, the humidity was controlled to be lower than 50%, the positive high voltage was 14 kV, the negative high voltage was -2 kV, and the liquid flow rate was 0.2 mm / min. The anode spinning slurry prepared in step (3) was used for electrospinning for 1 h to obtain a nanofiber catalyst layer. Under the conditions of 150°C and 0.3 MPa, the nanofiber catalyst layer was transferred to the other side of the proton exchange membrane to obtain an anode catalyst layer, thereby constructing a catalyst-coated membrane.

[0053] (5) The catalyst-coated membrane, gas diffusion layer, and frame material of step (4) are hot-pressed to prepare a nanofiber membrane electrode, which is then assembled together with a bipolar plate and a seal to form a single cell.

[0054] (6) The single cell obtained in step (5) was subjected to a 0.3 V constant potential treatment for 1 h with air flowing through the cathode and hydrogen flowing through the anode.

[0055] (7) Turn off the load and then purge for 20 min with nitrogen flowing through the cathode and hydrogen flowing through the anode.

[0056] (8) Then, under the conditions of nitrogen flowing through the cathode and hydrogen flowing through the anode, cyclic voltammetry scanning was performed between 0 and 1.2 V for 20 cycles to obtain a high-performance binder-free nanofiber membrane electrode.

[0057] Comparative Example 1 The difference between this comparative example and Example 1 is that steps (7) to (9) are not performed.

[0058] Comparative Example 2 This comparative example differs from Example 1 in that step (9) is not performed.

[0059] Comparative Example 3 The difference between this comparative example and Example 1 is that steps (7) to (8) are not performed.

[0060] Comparative Example 4 The difference between this comparative example and Example 1 is that the constant potential treatment potential in step (7) is increased to 0.5V.

[0061] Test example 1. Scanning electron microscope test: The single cell treated in Example 1 was dismantled to expose the cathode catalyst layer, and a scanning electron microscope test was performed together with the catalyst coating membrane in step (5) of Comparative Example 1. The scanning electron microscope test results of the cathode catalyst layer of Comparative Example 1 and Example 1 are as follows: Figure 1 and Figure 2 shown.

[0062] It can be clearly seen from the figure that the binder in the cathode catalyst layer after being treated in steps (7) to (9) of Example 1 is removed and the pores are increased.

[0063] 2. BET test: The surface areas of the cathode catalyst layer of Example 1 and the cathode catalyst layer of Comparative Example 1 after removal were analyzed using a specific surface area analyzer (BET). The results are as follows: Figure 3 As shown in the figure, it can be seen that after removing the binder, the BET surface area increases and the porosity increases.

[0064] 3. Polarization curve test: The cells treated in Examples 1 to 3 and the cells in Comparative Examples 1 to 3 were tested under fixed gas volume (air and hydrogen atmospheres, respectively), temperature, and back pressure. The operating point was 0.2 A / cm 2 , 0.4 A / cm 2 , 0.6 A / cm 2 ...4.0 A / cm 2(current density corresponding to 0.4 V voltage) and open circuit voltage (OCV), the dwell time at each operating point is ≥ 2 minutes, and the test results are as follows Figure 4 shown.

[0065] It can be seen from the figure that the performance of Example 1 is basically the same as that of Example 2, and both are much higher than that of Comparative Example 1, indicating that whether the preparation of the anode catalyst layer adopts spraying or electrospinning process has little effect on the performance, and the performance is significantly improved after removing the binder. From the comparison of Example 1 and Comparative Example 2, it can be seen that without cyclic voltammetry scanning, the performance of the catalyst will decline, but the decline is small. The performance of Comparative Example 3 is not much different from that of Comparative Example 1, indicating that the use of cyclic voltammetry scanning alone has little effect on the performance of the nanofiber membrane electrode. The performance of Example 1 and Comparative Example 4 is quite different, while the performance of Comparative Example 1 and Comparative Example 4 is basically the same, indicating that the high potential treatment did not completely remove the binder.

[0066] 4. CV curve test: After "3. Polarization curve test" is completed, turn off the air and start to pass a large flow of nitrogen to replace the air in the tube. Use H2 / N2 to purge the anode / cathode, and wait until the open circuit voltage drops below 0.2 V, and then perform a cyclic voltammetry test. H2 with a relative humidity of 100% is introduced into the anode of the nanofiber membrane electrode assembled in Example 1 and Comparative Example 1, and N2 with a relative humidity of 100% is introduced into the cathode, and a cyclic voltammetry test is performed under fixed gas volume, temperature and back pressure. During the test, the cathode is the working electrode, and the anode is used as the counter electrode and reference electrode to test the battery cathode. After the CV curve runs steadily, it is recorded, and the results are as follows Figure 5 shown.

[0067] As can be seen from the figure, the electrochemically active area (ECSA) of the membrane electrode obtained in Example 1 is larger than that of the membrane electrode obtained in Comparative Example 1, indicating that the three-phase interface of the membrane electrode increases after the binder is removed.

[0068] 5. Durability test: The cells treated in Example 1 and the cells in Comparative Example 1 were operated at a constant voltage of 0.6 V for 200 h. Polarization tests were performed as needed to determine the degradation process of the membrane electrode. The results are shown in the figure. Figure 6 shown.

[0069] As can be seen from the figure, the membrane electrode of Example 1 is more stable. After 30,000 cycles of CV aging, the performance degradation is much lower than that of the comparative example 1 in which the binder is not removed.

[0070] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance binder-free nanofiber membrane electrode, characterized in that: The steps include: The single cell assembled with the nanofiber membrane electrode was subjected to a constant potential treatment under the conditions of air flowing through the cathode and hydrogen flowing through the anode. After the treatment, nitrogen was passed through the cathode and hydrogen was passed through the anode for a set time. Cyclic voltammetry was then performed under the conditions of nitrogen flowing through the cathode and hydrogen flowing through the anode to obtain a high-performance binder-free nanofiber membrane electrode. Wherein, the cathode catalyst layer of the nanofiber membrane electrode is prepared by electrostatic spinning.

2. The preparation method according to claim 1, wherein The preparation method of the nanofiber membrane electrode is as follows: A nanofiber catalyst layer is prepared by electrospinning and transferred to one side of a proton exchange membrane to obtain a cathode catalyst layer. An anode slurry is sprayed on the other side of the proton exchange membrane to prepare an anode catalyst layer, thereby constructing a catalyst-coated membrane. Alternatively, the anode catalyst layer and the cathode catalyst layer are prepared by electrospinning and transferred to both sides of the proton exchange membrane to form a catalyst-coated membrane; The catalyst coating membrane and the gas diffusion layer are hot pressed to form a nanofiber membrane electrode.

3. The preparation method according to claim 2, wherein The catalysts of the anode catalyst layer and the cathode catalyst layer are independently selected from one or more of a platinum-carbon catalyst, a platinum-based alloy catalyst or a non-precious metal catalyst.

4. The preparation method according to claim 1, wherein The potential of the constant potential treatment is 0.2~0.4V.

5. The preparation method according to claim 1, wherein The constant potential treatment time is 40 to 80 minutes.

6. The preparation method according to claim 1, wherein After the constant potential treatment is completed, the cathode is purged with nitrogen and the anode is purged with hydrogen for 15 to 40 minutes.

7. The preparation method according to claim 1, wherein The potential interval of the cyclic voltammetry scan is 0-1.2V.

8. The preparation method according to claim 1, wherein The number of scanning cycles of the cyclic voltammetry scan is 15 to 30 cycles.

9. A high-performance binder-free nanofiber membrane electrode prepared by the preparation method according to any one of claims 1 to 8.

10. A fuel cell comprising the high-performance binder-free nanofiber membrane electrode according to claim 9.

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