A hydrophobic catalytic layer, a preparation method and application thereof, and a preparation method of a hydrophobic catalytic layer membrane electrode

Abstract

The present invention provides a hydrophobic catalytic layer, a preparation method and application thereof, and a preparation method of a hydrophobic catalytic layer membrane electrode, belonging to the technical field of fuel cells. The present invention uses the spherulitic granulation technology for the catalytic layer of the membrane electrode, and the insoluble resin can be redistributed in a good solvent, a poor solvent and a bridging agent according to the difference in solubility. As the good solvent volatilizes, it finally re-precipitates into spherulitic resin particles in the bridging agent. The spherical resin enables water to be evenly discharged along the surface of the sphere. At the same time, the water droplets remaining on the surface of the sphere can wet the membrane electrode, preventing the membrane electrode from losing water and causing inactivation of the membrane electrode. Thus, the problem of flooding of the membrane electrode is effectively solved, which is beneficial to the formation of a three-phase reaction interface and has broad application prospects and commercial value.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly relates to a hydrophobic catalytic layer, a preparation method and an application thereof, and a preparation method of a hydrophobic catalytic layer membrane electrode. Background Art

[0002] As a core component of a fuel cell, the membrane electrode is crucial for forming a gas-liquid-solid three-phase interface. At present, under high potential and long-term operating conditions, a large amount of water is easily generated in the cathode reaction on the cathode side of the membrane electrode. The high-potential condition is likely to cause the carbon structure of the catalytic layer to collapse, preventing water from being discharged. If the water generated by the cathode membrane electrode is not discharged in time, it is likely to cause flooding of the battery. Summary of the Invention

[0003] The purpose of the present invention is to provide a hydrophobic catalytic layer, a preparation method and an application thereof, and a preparation method of a hydrophobic catalytic layer membrane electrode, which effectively solve the problem of membrane electrode flooding and are conducive to forming a three-phase reaction interface.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a preparation method of a hydrophobic catalytic layer, comprising the following steps:

[0006] Mix a hydrophobic resin and a first good solvent, add a poor solvent and a bridging agent to the obtained resin solution, and perform crystallization to obtain resin spherulite particles;

[0007] Mix the resin spherulite particles, a carbon material, a second good solvent, a cationic surfactant and a catalyst, and perform dispersion to obtain a catalytic layer slurry;

[0008] Coat the catalytic layer slurry on a PTFE membrane respectively, and after drying, transfer the obtained cathode catalytic layer and anode catalytic layer to both sides of a proton exchange membrane to obtain a hydrophobic catalytic layer.

[0009] Preferably, the hydrophobic resin includes one or more of PTFE, PVDF, PS and PPS resins.

[0010] Preferably, the first good solvent and the second good solvent independently include ethanol, methanol, acetone, isopropanol, NMP or DMFC, and the poor solvent includes water.

[0011] Preferably, the bridging agent includes carbon tetrachloride, isopropyl acetate, toluene or isobutyl acetate; the mass ratio of the hydrophobic resin, the first good solvent, the poor solvent and the bridging agent is (0.1-1):(0.8-1):1:(0.1-0.3).

[0012] Preferably, the carbon material includes one or more of XC-72, multi-walled carbon nanotubes, BP2000, and Ketjen black; the catalyst includes one or more of Pt / C catalyst, PtCo / C catalyst, and PtNi / C catalyst; the cationic surfactant includes CTAB and / or SDBS.

[0013] Preferably, the mass ratio of the resin spherulite particles, carbon material, catalyst, and cationic surfactant is (0.3 - 0.6):(0.1 - 0.5):1:(0.1 - 0.3); the dispersion time is 2 - 4 h.

[0014] The present invention provides a hydrophobic catalytic layer prepared by the preparation method described in the above technical solution.

[0015] The present invention provides the application of the hydrophobic catalytic layer described in the above technical solution in a fuel cell.

[0016] The present invention provides a method for preparing a hydrophobic catalytic layer membrane electrode, including the following steps:

[0017] Hot press the hydrophobic catalytic layer described in the above technical solution and the diffusion layer to obtain a hydrophobic catalytic layer membrane electrode.

[0018] Preferably, the temperature of the hot press is 120 - 135 °C, the time is 120 - 135 s, and the pressure is 90 - 120 MPa.

[0019] The present invention provides a method for preparing a hydrophobic catalytic layer. The present invention innovatively applies the spherulite granulation technology to the catalytic layer of the membrane electrode, which can redistribute the insoluble resin according to the difference in solubility in a good solvent, a poor solvent, and a bridging agent. As the good solvent volatilizes, the resin finally re-precipitates into spherulite resin particles in the bridging agent. The spherical resin enables water to be evenly discharged along the surface of the sphere, and at the same time, the residual water droplets on the surface of the sphere can wet the membrane electrode, preventing the membrane electrode from losing water and causing inactivation of the membrane electrode (when adding resin alone, the resin is prone to agglomeration and cannot effectively discharge water, while the resin spherulite particles will not agglomerate and will effectively discharge water). The present invention utilizes the excellent water drainage effect of the resin spherulite particles to timely discharge the water generated at the cathode, effectively preventing the phenomenon of membrane electrode failure caused by cathode flooding, thus effectively solving the problem of membrane electrode flooding, facilitating the formation of a three-phase reaction interface, and having broad application prospects and commercial value.

[0020] In addition, the carbon material in the cathode of the hydrophobic catalytic layer also has a hydrophobic effect. Utilizing the synergistic effect of the resin and the carbon material can effectively form a gas-liquid-solid three-phase reaction interface, facilitating the timely discharge of reaction water, and further improving the hydrophobic effect of the catalytic layer and the overall performance of the membrane electrode. Description of the Drawings

[0021] Figure 1 Polarization curve comparison diagram of Example 1 and Comparative Example 1;

[0022] Figure 2 Columnar comparison diagram of current density at 0.65V for Examples 1-3 and Comparative Examples 1-3. Specific implementation mode

[0023] The present invention provides a preparation method of a hydrophobic catalytic layer, comprising the following steps:

[0024] Mix a hydrophobic resin and a first good solvent, add a poor solvent and a crosslinking agent to the obtained resin solution, and perform crystallization to obtain resin spherulite particles;

[0025] Mix the resin spherulite particles, carbon materials, a second good solvent, a cationic surfactant and a catalyst, and perform dispersion to obtain a catalytic layer slurry;

[0026] Coat the catalytic layer slurry on a PTFE membrane respectively, after drying, transfer the obtained cathode catalytic layer and anode catalytic layer to both sides of a proton exchange membrane to obtain a hydrophobic catalytic layer.

[0027] In the present invention, unless otherwise specified, the required materials or reagents are all commercially available products well-known to those skilled in the art.

[0028] The present invention mixes a hydrophobic resin and a first good solvent, adds a poor solvent and a crosslinking agent to the obtained resin solution, and performs crystallization to obtain resin spherulite particles.

[0029] In the present invention, the hydrophobic resin preferably includes one or more of PTFE, PVDF, PS and PPS resins; when there are two or more kinds of the above-mentioned hydrophobic resins, the present invention has no special limitation on the ratio of different kinds of hydrophobic resins, and any ratio is acceptable.

[0030] In the present invention, the first good solvent (a solvent with good solubility for the resin) preferably includes ethanol, methanol, acetone, isopropanol, NMP or DMFC, and the poor solvent (a solvent with poor solubility for the resin) preferably includes water.

[0031] In the present invention, the crosslinking agent preferably includes carbon tetrachloride, isopropyl acetate, toluene or isobutyl acetate; the mass ratio of the hydrophobic resin, the first good solvent, the poor solvent and the crosslinking agent is preferably (0.1-1):(0.8-1):1:(0.1-0.3), more preferably (0.2-0.4):1:1:(0.2-0.3), and further preferably 0.3:1:1:0.3.

[0032] In the present invention, the bridging agent represents a solvent that has good affinity for the resin and is immiscible with the poor solvent. The present invention utilizes the bridging agent to assist in the precipitation of the good solvent, playing the role of a bridge without chemical changes.

[0033] In the present invention, the process of mixing the hydrophobic resin and the first good solvent, adding the poor solvent and the bridging agent to the obtained resin solution for crystallization is preferably as follows: adding the first good solvent to the hydrophobic resin, mixing at 25 - 30°C for 0.5 h for the first time, then adding the poor solvent and the bridging agent, and mixing at 25 - 30°C for 0.5 h for the second time until the resin spherulites precipitate from the good solvent into the poor solvent. Filter the obtained solution and dry it to obtain resin spherulite particles; the first mixing and the second mixing are independently stirring, ultrasonic treatment or ball milling; the present invention has no special limitation on the stirring, ultrasonic treatment or ball milling, and it can be carried out according to the processes well-known in the art; the drying temperature is preferably 28°C.

[0034] In the present invention, during the crystallization process, the good solvent penetrates into the resin to form spherical resin droplets, and the droplets gradually diffuse into the poor solvent. The good solvent gradually precipitates. As the good solvent precipitates, the resin droplets gradually diffuse into the poor solvent. Under the action of the bridging agent, the resin droplets gradually crystallize and solidify, and maintain a spherical shape to form resin spherical particles.

[0035] After obtaining the resin spherulite particles, the present invention mixes the resin spherulite particles, carbon material, second good solvent, cationic surfactant and catalyst, and disperses them to obtain a catalytic layer slurry.

[0036] In the present invention, the carbon material preferably includes one or more of XC - 72, multi - walled carbon nanotubes, BP2000 and Ketjenblack; when there are two or more kinds of the above - mentioned carbon materials, the present invention has no special limitation on the ratio of different kinds of carbon materials, and it can be adjusted according to actual needs.

[0037] In the present invention, the second good solvent preferably includes ethanol, methanol, acetone, isopropanol, NMP or DMFC; the present invention has no special limitation on the dosage of the second good solvent, as long as it can ensure sufficient dispersion.

[0038] In the present invention, the catalyst preferably includes one or more of Pt / C catalyst, PtCo / C catalyst and PtNi / C catalyst; the Pt / C catalyst preferably includes 40% Pt / C catalyst (40% represents the mass content of Pt in the catalyst) or 60% Pt / C catalyst (60% represents the mass content of Pt in the catalyst). When there are two or more kinds of the above - mentioned catalysts, the present invention has no special limitation on the ratio of different kinds of catalysts, and it can be adjusted according to actual needs.

[0039] The present invention places no special limitation on the source of the catalyst, and commercially available products well-known in the art can be used; in the examples of the present invention, the specific source is JM Company.

[0040] In the present invention, the cationic surfactant preferably includes CTAB and / or SDBS. The present invention utilizes the cationic surfactant to reduce the surface energy of the catalyst and make the catalyst dispersion more uniform.

[0041] In the present invention, the mass ratio of the resin spherulite particles, carbon material, catalyst, and cationic surfactant is preferably (0.3 - 0.6):(0.1 - 0.5):1:(0.1 - 0.3), more preferably (0.4 - 0.53):(0.25 - 0.3):1:(0.1 - 0.125).

[0042] In the present invention, the mixing of the resin spherulite particles, carbon material, second good solvent, cationic surfactant, and catalyst preferably involves dissolving the resin spherulite particles and carbon material in the second good solvent, pre-treating for 0.5 - 1 h, and then adding the catalyst and cationic surfactant; the pre-treatment is preferably carried out under stirring, ultrasonic, or ball milling conditions.

[0043] In the present invention, the dispersion is preferably carried out under stirring, ultrasonic, or ball milling conditions. The temperature of the dispersion is preferably 25 - 30 °C, and the time is preferably 2 - 4 h, more preferably 3 h.

[0044] The present invention places no special limitation on the stirring, ultrasonic, or ball milling, and a catalytic layer slurry with uniform dispersion can be obtained according to the process well-known in the art.

[0045] After obtaining the catalytic layer slurry, the present invention coats the catalytic layer slurry on the PTFE membrane respectively. After drying, the obtained cathode catalytic layer and anode catalytic layer are transferred to both sides of the proton exchange membrane to obtain a hydrophobic catalytic layer.

[0046] In the present invention, when the catalytic layer slurry is used to prepare the anode catalytic layer, the catalyst loading is preferably 0.01 - 0.1 mg / cm 2 , more preferably 0.05 mg / cm 2 ; when the catalytic layer slurry is used to prepare the cathode catalytic layer, the catalyst loading is preferably 0.2 - 0.5 mg / cm 2 , more preferably 0.3 - 0.35 mg / cm 2 ; the loading in the present invention is preferably calculated based on the weight gain of the hydrophobic catalytic layer.

[0047] The present invention places no special limitation on the PTFE membrane, and commercially available products well-known in the art can all be used.

[0048] The present invention has no special limitation on the coating, and the required catalyst loading can be achieved according to the processes well-known in the art.

[0049] The present invention has no special limitation on the drying, and it can be carried out according to the processes well-known in the art; in the examples of the present invention, specifically, it is dried at 120 °C.

[0050] In the present invention, the proton exchange membrane is preferably a Nafion HP membrane with a thickness of 20 μm.

[0051] The present invention preferably uses two sides of a PTFE membrane to be respectively coated with the catalytic layer slurry and then transferred twice to both sides of the proton exchange membrane, or uses two PTFE membranes (one cathode and one anode) coated with the catalytic layer slurry and transfers them to both sides of the proton exchange membrane respectively.

[0052] In the present invention, the temperature of the transfer is preferably 120 °C. The present invention has no special limitation on the specific process of the transfer, and it can be carried out according to the processes well-known in the art.

[0053] The present invention provides a hydrophobic catalytic layer prepared by the preparation method described in the above technical solution.

[0054] The present invention provides the application of the hydrophobic catalytic layer described in the above technical solution in a fuel cell. The present invention has no special limitation on the application method, and it can be applied according to the methods well-known in the art; in the present invention, the hydrophobic catalytic layer is preferably used as a cathode catalytic layer and an anode catalytic layer in a membrane electrode.

[0055] The present invention provides a method for preparing a hydrophobic catalytic layer membrane electrode, comprising the following steps:

[0056] Hot press the hydrophobic catalytic layer described in the above technical solution and the diffusion layer to obtain a hydrophobic catalytic layer membrane electrode.

[0057] The present invention has no special limitation on the diffusion layer, and commercially available products well-known in the art can be used; the diffusion layer in the present invention preferably includes a cathode diffusion layer and an anode diffusion layer; in the examples of the present invention, the cathode diffusion layer and the anode diffusion layer used are both Toray Diffusion Layer YLS30T from Japan.

[0058] In the present invention, the temperature of the hot press is preferably 120 - 135 °C, more preferably 130 °C; the time is preferably 120 - 135 s, more preferably 130 s, and the pressure is preferably 90 - 120 MPa, more preferably 100 MPa.

[0059] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0060] In the following embodiments, the thickness of the Nafion HP membrane is 20 μm.

[0061] Example 1

[0062] Weigh 10 g of PTFE resin and place it in a round-bottom container. Add 50 g of ethanol, and use a magnetic stirrer that can be heated. After stirring at 30 °C for 0.5 h, then add 50 g of water and 15 g of isopropyl acetate, and stir at 30 °C for 0.5 h until resin spherulites precipitate. Filter the solution and dry it at a constant temperature of 28 °C to obtain PTFE resin spherulites;

[0063] Weigh 4 g of the PTFE resin spherulites and 3 g of XC-72, dissolve them with 20 mL of ethanol, stir at 30 °C for 0.5 h, add 10 g of PtCo / C catalyst and 1 g of CTAB, and stir magnetically at 30 °C for 3 h to obtain the catalytic layer slurry;

[0064] Apply the catalytic layer slurry onto the PTFE membrane respectively. The catalyst loading in the cathode catalytic layer is 0.35 mg / cm 2 , and the catalyst loading in the anode catalytic layer is 0.1 mg / cm 2 , and dry the PTFE membrane at 120 °C;

[0065] Transfer the PTEF membrane with the cathode and anode catalytic layers to the Nafion HP membrane at 120 °C to obtain the CCM catalytic layer.

[0066] Example 2

[0067] Weigh 15 g of PVDF resin and place it in a round-bottom container. Add 50 g of NMP, and use a ball mill stirrer. After ball milling at 25 °C for 0.5 h, then add 50 g of water and 10 g of carbon tetrachloride, and stir at 25 °C for 0.5 h until resin spherulites precipitate. Filter the solution and dry it at a constant temperature of 28 °C to obtain PVDF resin spherulites;

[0068] Weigh 5 g of the PVDF resin spherulites and 3 g of multi-walled carbon nanotubes, dissolve them with 25 mL of NMP, ball mill at 25 °C for 0.5 h, add 12 g of PtNi / C catalyst and 1.5 g of SDBS, and ball mill at 25 °C for 3 h to obtain a uniformly dispersed catalytic layer slurry;

[0069] Apply the catalytic layer slurry onto the PTFE membrane respectively. The catalyst loading in the cathode catalytic layer is 0.3 mg / cm 2 , and the catalyst loading in the anode catalytic layer is 0.1 mg / cm 2 . Dry the PTFE membrane at 120 °C;

[0070] Transfer the PTEF membrane with the cathode and anode catalytic layers to the Nafion HP membrane at 120 °C to obtain the CCM catalytic layer.

[0071] Example 3

[0072] Weigh 24 g of PPS resin and place it in a round-bottom container. Add 48 g of isopropanol, and use an ultrasonic disperser to ultrasonically disperse for 0.5 h at 30 °C. Then add 60 g of water and 18 g of toluene, and ultrasonically disperse for 0.5 h at 30 °C until resin spherulites precipitate. Filter the solution and dry it at a constant temperature of 28 °C to obtain PPS resin spherulites;

[0073] Weigh 8 g of the PPS resin spherulites and 5 g of Ketjenblack, dissolve them with 30 mL of isopropanol, ultrasonically disperse for 0.5 h at 30 °C, add 15 g of 60% Pt / C catalyst and 2 g of CTAB, and ultrasonically disperse for 3 h at 30 °C to obtain a uniformly dispersed catalytic layer slurry;

[0074] Apply the catalytic layer slurry onto the PTFE membrane respectively. The catalyst loading in the cathode catalytic layer is 0.5 mg / cm 2 , and the catalyst loading in the anode catalytic layer is 0.05 mg / cm 2 . Dry the PTFE membrane at 120 °C;

[0075] Transfer the PTEF membrane with the cathode and anode catalytic layers to the Nafion HP membrane at 120 °C to obtain the CCM catalytic layer.

[0076] Comparative Example 1

[0077] Weigh 4 g of PTFE resin (not spherulitized) and 3 g of XC-72, dissolve them with 20 mL of ethanol, stir for 0.5 h at 30 °C, add 10 g of PtCo / C catalyst and 1 g of CTAB, and magnetically stir for 3 h at 30 °C to obtain a uniformly dispersed catalytic layer slurry;

[0078] Apply the catalytic layer slurry onto the PTFE membrane respectively. The catalyst loading in the cathode catalytic layer is 0.35 mg / cm 2 , and the catalyst loading in the anode catalytic layer is 0.1 mg / cm 2 . Dry the PTFE membrane at 120 °C;

[0079] Transfer the PTEF membrane carrying the cathode and anode catalyst layers to the Nafion HP membrane at 120 °C to obtain the CCM catalyst layer.

[0080] Comparative Example 2

[0081] Weigh 5 g of PVDF resin (non-spherulitic) and 3 g of multi-walled carbon nanotubes, dissolve them in 25 mL of NMP, ball mill at 25 °C for 0.5 h, add 12 g of PtNi / C catalyst and 1.5 g of SDBS, and ball mill at 25 °C for 3 h to obtain a uniformly dispersed catalyst layer slurry.

[0082] Coat the catalyst layer slurry on the PTFE membrane respectively. The catalyst loading in the cathode catalyst layer is 0.3 mg / cm 2 , and the catalyst loading in the anode catalyst layer is 0.1 mg / cm 2 , and dry the PTFE membrane at 120 °C;

[0083] Transfer the PTEF membrane carrying the cathode and anode catalyst layers to the Nafion HP membrane at 120 °C to obtain the CCM catalyst layer.

[0084] Comparative Example 3

[0085] Weigh 8 g of PPS resin (non-spherulitic) and 5 g of Ketjenblack, dissolve them in 30 mL of isopropanol, sonicate at 30 °C for 0.5 h, add 15 g of 60% Pt / C catalyst and 2 g of CTAB, and sonicate at 30 °C for 3 h to obtain a uniformly dispersed catalyst layer slurry.

[0086] Coat the catalyst layer slurry on the PTFE membrane respectively. The catalyst loading in the cathode catalyst layer is 0.5 mg / cm 2 , and the catalyst loading in the anode catalyst layer is 0.05 mg / cm 2 , and dry the PTFE membrane at 120 °C;

[0087] Transfer the PTEF membrane carrying the cathode and anode catalyst layers to the Nafion HP membrane at 120 °C to obtain the CCM catalyst layer.

[0088] Performance Test

[0089] 1) Hydrophobic angle test: Place the hydrophobic catalyst layers prepared in different cases on the OCA251 test bench, drop water droplets on the catalyst layer using a syringe, take a screenshot with the OCA251 test software, and measure the hydrophobic angle size with a measuring tool. The results are shown in Table 1.

[0090] Table 1 Hydrophobic angles of Examples 1 - 3 and Comparative Examples 1 - 3

[0091] Example 1 Comparative Example 1 Example 2 Comparative Example 2 Example 3 Comparative Example 3 Hydrophobic angle 128.1° 87.5° 132.4° 76.3° 126.8° 85.3°

[0092] From the comparative analysis in Table 1, the hydrophobic angles of the catalyst layers prepared in Examples 1 to 3 are much larger than those in Comparative Examples 1 to 3, indicating that resin spherulites are beneficial to the timely discharge of reaction water.

[0093] 2) Polarization performance test of hydrophobic membrane electrode:

[0094] The CCM catalyst layer prepared in Example 1 and the Toray diffusion layers YLS30T for the anode and cathode were hot-pressed at 120 °C for 120 s under a pressure of 90 MPa to obtain a hydrophobic membrane electrode (MEA).

[0095] The CCM prepared in Example 2 and the Toray diffusion layers YLS30T for the anode and cathode were hot-pressed at 130 °C for 130 s under a pressure of 100 MPa to obtain a hydrophobic membrane electrode (MEA).

[0096] The CCM prepared in Example 3 and the prepared Toray diffusion layers YLS30T for the anode and cathode were hot-pressed at 120 °C for 120 s under a pressure of 90 MPa to obtain a hydrophobic membrane electrode (MEA).

[0097] The CCM prepared in Comparative Example 1 and the Toray diffusion layers YLS30T for the anode and cathode were hot-pressed at 120 °C for 120 s under a pressure of 90 MPa to obtain a hydrophobic membrane electrode (MEA).

[0098] The CCM prepared in Comparative Example 2 and the Toray diffusion layers YLS30T for the anode and cathode were hot-pressed at 130 °C for 130 s under a pressure of 100 MPa to obtain a hydrophobic membrane electrode (MEA).

[0099] The CCM prepared in Comparative Example 3 and the Toray diffusion layers YLS30T for the anode and cathode were hot-pressed at 120 °C for 120 s under a pressure of 90 MPa to obtain a hydrophobic membrane electrode (MEA).

[0100] Polarization test conditions: 30 - 570 A / cm 2 As the scanning current density, the anode stoichiometry is 2.2, and the cathode stoichiometry is 3.5. The anode humidity is 40% RH, the cathode humidity is 60% RH, the hydrogen back pressure is 135 kPa, and the air back pressure is 120 kPa.

[0101] Figure 1 Figure is the polarization curve of Example 1 and Comparative Example 1. From Figure 1 the analysis, at 0.65 V, the current density of the polarization curve of Example 1 is 1.64 A / cm 2 , and the current density of the polarization curve of Comparative Example 1 is 1.48 A / cm2 (the current density at 0.65 V can generally describe the performance of the membrane electrode). It shows that the mass transfer effect of the catalyst layer in Example 1 is better.

[0102] Figure 2Column comparison chart of current density for Examples 1 to 3 and Comparative Examples 1 to 3 at 0.65V. From Figure 2 It can be seen that the current density of the examples is greater than that of the comparative examples, indicating that the timely discharge of the reaction water is beneficial to the gas-liquid-solid three-phase reaction interface, improving the oxygen mass transfer capacity, and thus improving the overall performance of the membrane electrode.

[0103] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a hydrophobic catalytic layer, characterized in that, It includes the following steps: Mix a hydrophobic resin with a first good solvent, add a poor solvent and a cross-linking agent to the resulting resin solution, and perform crystallization to obtain resin spherulite particles; Mix the resin spherulite particles, a carbon material, a second good solvent, a cationic surfactant and a catalyst, and perform dispersion to obtain a catalytic layer slurry; Coat the catalytic layer slurry on a PTFE membrane respectively. After drying, transfer the obtained cathode catalytic layer and anode catalytic layer to both sides of a proton exchange membrane to obtain a hydrophobic catalytic layer.

2. The preparation method according to claim 1, wherein The hydrophobic resin includes one or more of PTFE, PVDF, PS and PPS resins.

3. The preparation method according to claim 1, wherein, The first good solvent and the second good solvent independently include ethanol, methanol, acetone, isopropanol, NMP or DMFC, and the poor solvent includes water.

4. The preparation method according to claim 1, characterized in that The cross-linking agent includes carbon tetrachloride, isopropyl acetate, toluene or isobutyl acetate; the mass ratio of the hydrophobic resin, the first good solvent, the poor solvent and the cross-linking agent is (0.1-1):(0.8-1):1:(0.1-0.3).

5. The preparation method according to claim 1, characterized in that, The carbon material includes one or more of XC-72, multi-walled carbon nanotubes, BP2000 and Ketjenblack; the catalyst includes one or more of Pt / C catalyst, PtCo / C catalyst and PtNi / C catalyst; the cationic surfactant includes CTAB and / or SDBS.

6. The preparation method according to claim 1, wherein The mass ratio of the resin spherulite particles, the carbon material, the catalyst and the cationic surfactant is (0.3-0.6):(0.1-0.5):1:(0.1-0.3); the dispersion time is 2-4 h.

7. A hydrophobic catalytic layer prepared by the preparation method according to any one of claims 1 to 6.

8. Application of the hydrophobic catalytic layer according to claim 7 in a fuel cell.

9. A method for preparing a hydrophobic catalytic layer membrane electrode, characterized in that, It includes the following steps: Hot press the hydrophobic catalytic layer according to claim 7 with a diffusion layer to obtain a hydrophobic catalytic layer membrane electrode.

10. The preparation method according to claim 9, characterized in that, The temperature of the hot pressing is 120-135 °C, the time is 120-135 s, and the pressure is 90-120 MPa.

Images