A method for preparing a fuel cell catalyst slurry and a catalyst slurry

Abstract

The present application relates to the field of fuel cell, and provides a preparation method of fuel cell catalyst slurry, which comprises the following steps: S1, adding a surfactant for improving the dispersibility of carbon material into water, adding the carbon material while stirring, and obtaining carbon material slurry through specific dispersion; S2, adding a catalyst, an ionomer and a low-boiling organic substance into water under stirring, and obtaining catalyst pre-dispersed slurry after mixing; and S3, taking the carbon material slurry and the catalyst pre-dispersed slurry according to the proportion, mixing and stirring, and dispersing to obtain catalyst slurry. The present application has the advantages that: the present application adopts the mode of separately dispersing the carbon material and the catalyst and then mixing and processing, improves the dispersibility of the carbon material in the catalyst slurry, and enables the carbon material to play a role of accelerating water drainage in the membrane electrode without hindering the mass transfer effect.

Description

Technical Field

[0001] This invention relates to the field of fuel cells, and more specifically, to a method for preparing fuel cell catalyst slurry and the catalyst slurry itself. Background Technology

[0002] The membrane electrode assembly (MEA) is the core of a proton exchange membrane fuel cell. Within the MEA, the structure of the catalyst layer on the proton exchange membrane, especially the cathode catalyst layer, significantly impacts its performance and lifespan. The cathode catalyst layer not only serves as the site of the oxygen reduction reaction but also witnesses complex processes such as oxygen conduction, water conduction, heat conduction, and proton and electron transport. Water conduction has a substantial impact on MEA performance. A certain water content needs to be maintained in the catalyst layer to promote proton transport, while simultaneously controlling the water content to prevent flooding of the catalyst layer and hindering oxygen transport.

[0003] Currently, the application of fuel cells in heavy-duty trucks and other fields is increasingly focused on performance under high current. However, at high current densities, more water is generated, necessitating hydrophobic treatment of the catalyst layer. Numerous publications have disclosed or reported methods to improve the hydrophobicity of the catalyst layer using additives, such as hydrophobic PTFE, PVDF, and hydrophobic carbon materials. Materials like PTFE and PVDF, being non-conductive, increase the electronic resistance of the catalyst layer; while hydrophobic carbon materials, due to their superior conductivity and hydrophobicity, are widely studied as slurry additives.

[0004] However, graphitized carbon materials are generally difficult to disperse, especially in the slot coating technique commonly used in CCM preparation. This is because the wet film coating is formed in a single step, placing higher demands on the catalyst slurry compared to traditional spraying methods. The slurry requires a higher solids content (typically >5 wt%), which makes carbon material dispersion even more difficult. Poor dispersion of the added carbon material in the slurry leads to uneven distribution of substances within the catalyst layer, with the added carbon material concentrated in certain areas. Since these added carbon materials themselves have no catalytic function, poor dispersion can actually hinder oxygen transport, thus affecting the performance of the membrane electrode assembly. Summary of the Invention

[0005] The present invention aims to overcome at least one of the defects of the prior art and provide a method for preparing fuel cell catalyst slurry and catalyst slurry, which can improve the dispersion of carbon materials in the cathode catalyst slurry of membrane electrode and improve the performance of membrane electrode.

[0006] One object of the present invention is to provide a method for preparing fuel cell catalyst slurry, comprising the following steps:

[0007] S1. Add a surfactant to water to improve the dispersibility of carbon materials, and add carbon materials while stirring. After a specific dispersion process, a carbon material slurry is obtained.

[0008] S2. Under the stirring state of water, add catalyst, ionomer, and low-boiling-point organic matter, and mix to obtain catalyst pre-dispersion slurry;

[0009] S3. Weigh the carbon material slurry and the catalyst pre-dispersion slurry according to the ratio, mix and stir, disperse to obtain the catalyst slurry.

[0010] In step S2, preferably, the catalyst, ionomer, and low-boiling-point organic compound are added sequentially and mixed evenly to obtain a catalyst dispersion slurry.

[0011] The surfactant improves the dispersibility of the carbon material, and the surfactant is one or more of CMC, PVP, and sulfonic acid resin. The carbon material is a carbon material with a carbon content ≥90wt%, such as graphitized carbon spheres, graphitized carbon nanotubes, carbon fibers, graphene, or three-dimensional graphene. The catalyst slurry has a solid content of 5-20wt%, preferably 10-15wt%; the ionomer is a perfluorosulfonic acid resin with a solid content of 5-30wt% and a viscosity of 5-1000cP; the low-boiling-point organic compound refers to one or more of methanol, ethanol, n-propanol, isopropanol, tert-butanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, n-butanol, and isobutanol.

[0012] The specific dispersion mentioned in step S1 is performed using a high-pressure dispersion device, a bead mill, or a planetary ball mill. After dispersion, the average particle size of the carbon material is ≤1.5μm, preferably ≤0.8μm. In step S3, dispersion is performed using a mixer, a high-pressure dispersion device, or a ball mill, and the dispersion intensity is lower than that in step S1.

[0013] When adding graphitized carbon materials to improve the hydrophobicity of the coating, ensuring the dispersion of the carbon materials in the slurry is crucial to guaranteeing the performance of the membrane electrode assembly (MEA). The dispersion of graphitized carbon materials is particularly difficult and requires stringent dispersion conditions. In contrast, catalyst slurries typically require lower dispersion pressures. Excessive dispersion pressure can damage the catalyst structure, such as causing platinum to detach; conversely, insufficient dispersion pressure leads to poor dispersion and uneven distribution of the carbon materials, negatively impacting the MEA's performance.

[0014] This technical solution employs a method of first separating and dispersing the carbon material and the catalyst before mixing them. This achieves full dispersion of the carbon material without damaging the catalyst, which is beneficial for achieving uniformity of the carbon material in the slurry. Especially when the solid content of the slurry is relatively high, it improves the dispersibility of the carbon material, enabling it to accelerate drainage in the membrane electrode without hindering the mass transfer effect.

[0015] Furthermore, in step S1, the dispersion pressure of the high-pressure dispersion is >15000psi.

[0016] Furthermore, in step S3, high-pressure dispersion is used, and the dispersion pressure of the high-pressure dispersion is 10%-70% of the dispersion pressure in step S1.

[0017] Preferably, the dispersion pressure in step S3 is 20% to 50% of the dispersion pressure in step S1.

[0018] Furthermore, the carbon content of the carbon material is ≥90wt%.

[0019] The content of oxygen and other elements in the carbon material is <10wt%, preferably, the carbon content in the carbon material is ≥95wt%.

[0020] Further, in step S1, the amount of carbon material in the carbon material slurry is 0.01 wt% to 5 wt%.

[0021] Furthermore, the mass ratio of the carbon material to the catalyst is (0.0005-0.05):1.

[0022] Preferably, the mass ratio of the carbon material to the catalyst is (0.001-0.05):1.

[0023] Furthermore, the mass ratio of the surfactant to the carbon material is (0.1-2):1, and the mass ratio of the ionomer to the catalyst is (0.1-1):1.

[0024] Preferably, the mass ratio of the ionomer to the catalyst is (0.3-0.6):1.

[0025] Furthermore, the catalyst slurry contains 10-50 wt% low-boiling-point organic matter, the catalyst pre-dispersion contains 5-30 wt% ionomers, and the viscosity is 5-1000 cP.

[0026] Preferably, the content of low-boiling-point organic matter in the catalyst slurry is 15-30 wt%.

[0027] Furthermore, the catalyst is Pt / C or PtM / C, wherein M is Co, Fe, Ni, Cu, Au, Ag, Pd, Ir or Ru.

[0028] The catalyst has a platinum content of 20-70 wt%; preferably, when the catalyst is Pt / C, the platinum content is 30-60 wt%, and when the catalyst is PtM / C, the platinum content is 25-50 wt%.

[0029] Another object of the present invention is to provide a fuel cell catalyst slurry, which is prepared by any of the fuel cell catalyst slurry preparation methods described above.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adopts the method of first separating and dispersing the carbon material and the catalyst and then mixing them, so that the carbon material and the catalyst can be dispersed under their respective optimal dispersion conditions. This reduces the particle size of the carbon material without damaging the catalyst, allowing it to be fully dispersed. This is beneficial to achieving the uniformity of the carbon material in the slurry, especially when the solid content of the slurry is relatively high, thus improving the dispersibility of the carbon material. This allows it to play a role in accelerating drainage in the membrane electrode without hindering the mass transfer effect. Attached Figure Description

[0031] Figure 1 This is a graph showing the particle size variation of carbon materials under different dispersion pressures.

[0032] Figure 2 The graph shows the particle size variation of the slurry in Examples 1 to 4 and Comparative Examples 1 to 6.

[0033] Figure 3 The polarization curves are for Example 1, Comparative Example 2, and Comparative Example 6.

[0034] Figure 4 The polarization curves are for Example 1, Comparative Example 1, and Comparative Example 3.

[0035] Figure 5 The polarization curves are for Example 1 and Comparative Example 5.

[0036] Figure 6 The polarization curves are for Example 1, Example 2, Example 4 and Comparative Example 4. Detailed Implementation

[0037] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0038] Example 1

[0039] This embodiment provides a method for preparing fuel cell catalyst slurry, including the following steps:

[0040] S1. Preparation of carbon material slurry. Weigh 7.5g of 20wt% Chemours D2020 (Nafion). TMThe perfluorosulfonic acid resin dispersion was added to a mixed solvent of water and n-propanol, with a total weight of 90g and a water-to-propanol ratio of 1:1. After stirring evenly, 3.0g of graphene (TG1000, CarbonMei New Materials) (carbon content of approximately 96%) was added to the above mixed solution and stirred evenly. The mixture was then dispersed using a high-pressure uniform dispersion device at a dispersion pressure of 35000psi to obtain a carbon material slurry.

[0041] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TM Perfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0042] S3. Weigh 10g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a Beads mill at 1000 rpm for 10 minutes. Then collect the well dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0043] Example 2

[0044] This embodiment provides a method for preparing fuel cell catalyst slurry, including the following steps:

[0045] S1. Preparation of carbon material slurry. Weigh 3.7g of 20wt% Chemours D2020 (Nafion™) perfluorosulfonic acid resin dispersion and add it to a mixed solvent of water and n-propanol. The total weight of water and n-propanol is 94.8g, and the ratio of water to n-propanol is 1:1. Stir evenly, add 1.5g of graphene (TG1000, CarbonMei New Materials) (carbon content of about 96%) to the above mixed solution, stir evenly, and disperse using a high-pressure uniform dispersion device at a dispersion pressure of 35000psi to obtain carbon material slurry.

[0046] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TMPerfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0047] S3. Weigh 10g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a Beads mill at 1000 rpm for 10 minutes. Then collect the well dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0048] Example 3

[0049] This embodiment provides a method for preparing fuel cell catalyst slurry, including the following steps:

[0050] S1. Preparation of carbon material slurry. Weigh 3.7g of 20wt% Chemours D2020 (Nafion). TM The perfluorosulfonic acid resin dispersion was added to a mixed solvent of water and n-propanol, with a total weight of 94.8 g and a water-to-propanol ratio of 1:1. After stirring evenly, 1.5 g of single-walled carbon nanotubes (CNT002, Carbon Graphene Technology Co., Ltd.) (carbon content of 96.3%) was added to the above mixed solution and stirred evenly. The mixture was then dispersed using a high-pressure uniform dispersion device at a dispersion pressure of 35,000 psi to obtain a carbon material slurry.

[0051] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TM Perfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0052] S3. Weigh 10g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a Beads mill at 1000 rpm for 10 minutes. Then collect the well dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0053] Example 4

[0054] This embodiment provides a method for preparing fuel cell catalyst slurry, including the following steps:

[0055] S1. Preparation of carbon material slurry. Weigh 7.5g of 20wt% Chemours D2020 (Nafion). TM The perfluorosulfonic acid resin dispersion was added to a mixed solvent of water and n-propanol, with a total weight of 90g and a water-to-propanol ratio of 1:1. After stirring evenly, 3.0g of graphene (TG1000, CarbonMei New Materials) (carbon content of approximately 96%) was added to the above mixed solution and stirred evenly. The mixture was then dispersed using a high-pressure uniform dispersion device at a dispersion pressure of 35000psi to obtain a carbon material slurry.

[0056] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TM Perfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0057] S3. Weigh 10g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a high-pressure homogenizer at a dispersion pressure of 17000psi. Then collect the well dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0058] Comparative Example 1

[0059] This comparative example provides a method for preparing a fuel cell catalyst slurry, including the following steps:

[0060] S1. Preparation of pre-dispersion slurry of carbon-containing catalyst: Weigh 9.0g of Tanaka Precious Metals Co., Ltd.'s TEC10E50E catalyst Pt / C, 0.3g of graphene (TG1000, CarbonMei New Materials), and 22.5g of 20wt% Chemours D2020 (Nafion). TM 8.9 g of perfluorosulfonic acid resin dispersion, 8.9 g of ethanol, and 59.6 g of ultrapure water were prepared. The stirrer was placed in a beaker containing the weighed water and stirred at 200 rpm. The catalyst was slowly added to the water and stirred for 2 minutes to ensure that the catalyst was wetted. Then the perfluorosulfonic acid resin dispersion was added and stirred for 2 minutes. The ethanol was added and the stirring was continued for 5-10 minutes to ensure that the materials were mixed evenly, thus obtaining a pre-dispersed slurry of the carbon-containing catalyst.

[0061] S2. The pre-dispersed liquid in S1 is dispersed using a Beads mill disperser at a speed of 1000 rpm for 10 min. The dispersed catalyst slurry is then collected and degassed to obtain the catalyst slurry.

[0062] Comparative Example 2

[0063] This comparative example provides a method for preparing a fuel cell catalyst slurry, including the following steps:

[0064] S1. Preparation of catalyst pre-dispersion slurry: Weigh 9.0g of Tanaka Precious Metals Co., Ltd.'s TEC10E50E catalyst Pt / C, 22.5g of 20wt% Chemours D2020 (Nafion™) perfluorosulfonic acid resin dispersion, 8.9g of ethanol, and 59.6g of ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the perfluorosulfonic acid resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0065] S2. The catalyst pre-dispersed slurry from step S1 is dispersed using a Beads mill disperser at a speed of 1000 rpm for 10 min. The dispersed catalyst slurry is then collected and degassed to obtain the catalyst slurry.

[0066] Comparative Example 3

[0067] This comparative example provides a method for preparing a fuel cell catalyst slurry, including the following steps:

[0068] S1. Preparation of carbon material slurry. Weigh 15g of 20wt% Chemours D2020 (Nafion). TMThe perfluorosulfonic acid resin dispersion was added to a mixed solvent of water and n-propanol, with a total weight of 90g and a water-to-propanol ratio of 1:1. After stirring until homogeneous, 6.0g of graphene (TG1000, CarbonMei New Materials) was added to the above mixed solution and stirred until homogeneous. The mixture was then dispersed using a high-pressure uniform dispersion device at a dispersion pressure of 6000psi to obtain a carbon material slurry.

[0069] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TM Perfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0070] S3. Weigh 10g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a Beads mill at 1000 rpm for 10 minutes. Then collect the well dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0071] Comparative Example 4

[0072] This comparative example provides a method for preparing a fuel cell catalyst slurry, including the following steps:

[0073] S1. Preparation of carbon material slurry. Weigh 15g of 20wt% Chemours D2020 (Nafion). TM The perfluorosulfonic acid resin dispersion was added to a mixed solvent of water and n-propanol, with a total weight of 79g and a water-to-propanol ratio of 1:1. After stirring evenly, 6.0g of graphene (TG1000, CarbonMei New Materials) was added to the above mixed solution and stirred evenly. The mixture was then dispersed using a high-pressure uniform dispersion device at a dispersion pressure of 35000psi for 8 times to obtain a carbon material slurry.

[0074] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TMPerfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0075] S3. Weigh 20g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a Beads mill at 1000 rpm for 10 minutes. Then collect the dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0076] Comparative Example 5

[0077] This comparative example provides a method for preparing a fuel cell catalyst slurry, including the following steps:

[0078] S1. Preparation of carbon material slurry. Weigh 7.5g of 20wt% Chemours D2020 (Nafion). TM The perfluorosulfonic acid resin dispersion was added to a mixed solvent of water and n-propanol, with a total weight of 90g and a water-to-propanol ratio of 1:1. After stirring evenly, 3.0g of XF269 porous graphene (carbon content <90%) was added to the above mixed solution and stirred evenly. The mixture was then dispersed using a high-pressure uniform dispersion device at a dispersion pressure of 35000psi for 8 times to obtain a carbon material slurry.

[0079] S2. Preparation of catalyst pre-dispersion slurry. Weigh 9.0 g of TEC10E50E Pt / C catalyst from Tanaka Precious Metals Co., Ltd., and weigh 22.5 g of 20 wt% Chemours D2020 (Nafion). TM Perfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0080] S3. Weigh 10g of the well dispersed carbon material slurry and slowly add it to the catalyst pre-dispersed slurry in step S2. Continue stirring for 5-10 minutes. Disperse the slurry using a Beads mill at 1000 rpm for 10 minutes. Then collect the well dispersed catalyst slurry and degas it to obtain the catalyst slurry.

[0081] Comparative Example 6

[0082] This comparative example provides a method for preparing a fuel cell catalyst slurry, including the following steps:

[0083] S1. Preparation of catalyst pre-dispersion slurry: Weigh 9.0g of Tanaka Precious Metals Co., Ltd.'s TEC10E50E catalyst Pt / C, and 22.5g of 20wt% Chemours D2020 (Nafion) TM Perfluorosulfonic acid resin dispersion, 8.9g ethanol, 59.6g ultrapure water; place the stirrer in a beaker containing the weighed water and start stirring at 200rpm. Slowly add the catalyst Pt / C to the water and stir for 2min to ensure the catalyst is wetted. Then add the resin dispersion and stir for 2min. Add the ethanol and continue stirring for 5-10min to ensure the materials are mixed evenly, thus obtaining the catalyst pre-dispersion slurry.

[0084] S2. The catalyst pre-dispersed slurry from step S1 is dispersed using a high-pressure homogenizer at a pressure of 30,000 psi and dispersed 8 times. The dispersed catalyst slurry is then collected and degassed to obtain the catalyst slurry.

[0085] The catalyst slurries prepared in Examples 1-4 and Comparative Examples 1-6 were respectively coated onto one side of a proton exchange membrane using a slit coating method, and dried at 90°C to obtain a cathode catalyst layer. The platinum loading of the cathode catalyst layer was 0.35 mg / cm³. 2 Anode catalyst slurry was coated on the other side of the proton exchange membrane and dried to obtain CCM. The platinum loading of the anode was 0.1 mg / cm2. The frame and carbon paper were further assembled to obtain membrane electrodes, and polarization curves of each membrane electrode were tested.

[0086] Figure 1 To illustrate the particle size variation of carbon materials under different dispersion pressures, the carbon material is graphene (TG1000). When dispersing graphene (TG1000) using a high-pressure dispersion device, multiple dispersions at a high dispersion pressure (35000psi) are required to achieve the desired dispersion effect. However, using a lower dispersion pressure (6000psi) results in a poorer dispersion effect of graphene.

[0087] Figure 2 This is a graph showing the particle size variation of the slurry in Examples 1-4 and Comparative Examples 1-6. Combined with... Figure 1 and Figure 2 It can be seen that the reason why the performance cannot be improved is the uneven slurry caused by the uneven dispersion of carbon materials.

[0088] Figure 3The figures show the polarization curves for Example 1, Comparative Example 2, and Comparative Example 6. Adding a certain amount of pre-dispersed graphitized carbon material can optimize the high electrical density performance of the membrane electrode. Simultaneously, combined with... Figure 2 and Figure 6 It is known that when high pressure is used to directly disperse the catalyst slurry, the catalyst particles will be over-dispersed, which may lead to the destruction of the catalyst structure and make the catalyst particles in the slurry too small; thus, the performance of the membrane electrode will decline.

[0089] Figure 4 The figures show the polarization curves of Example 1, Comparative Example 1, and Comparative Example 3. (In conjunction with...) Figure 2 and Figure 3 It is evident that when carbon materials and catalysts are mixed and dispersed together, the resulting slurry exhibits poor particle size distribution, similar to a slurry with poorly dispersed carbon materials, thus failing to improve membrane electrode performance. However, in Example 1, the carbon materials were first fully dispersed before being mixed and dispersed with the catalyst slurry, resulting in better particle size distribution and improved membrane electrode performance.

[0090] Figure 5 The figures show the polarization curves for Example 1 and Comparative Example 5. Adding well-dispersed graphitized carbon material can improve the high electrical density performance of the membrane electrode, but adding carbon material with more oxygen-containing groups (lower carbon content) does not contribute to improving the high electrical density performance of the membrane electrode; simultaneously, combined with... Figure 2 It is known that adding hydrophilic carbon materials, although they can be dispersed in the normal slurry dispersion process, cannot improve the performance of the membrane electrode.

[0091] Figure 6 The figures show the polarization curves for Examples 1, 2, 4, and Comparative Example 4. It can be seen that when the amount of graphitized carbon support added is less than or equal to 5 wt%, it can improve the performance of the membrane electrode. However, when the amount added is 13 wt% of the catalyst mass, it actually reduces the high electrical density performance of the membrane electrode. This is because excessive inert material (which has no catalytic activity compared to the catalyst) hinders the mass transfer process.

[0092] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a fuel cell catalyst slurry, characterized in that, Includes the following steps: S1. Add a surfactant to water to improve the dispersibility of carbon materials, and add carbon materials while stirring. After specific dispersion, a carbon material slurry is obtained. S2. Under the stirring state of water, add catalyst, ionomer, and low-boiling-point organic matter, and mix to obtain catalyst pre-dispersion slurry; S3. Weigh the carbon material slurry and catalyst pre-dispersion slurry according to the ratio, mix and stir, disperse to obtain the catalyst slurry; In step S1, the dispersion is carried out using a high-pressure dispersion device with a dispersion pressure >15000 psi; the carbon content of the carbon material is ≥90 wt%; and the amount of carbon material in the carbon material slurry is 0.01 wt%~5 wt%. The ionomer is a perfluorosulfonic acid resin with a solid content of 5-30 wt% and a viscosity of 5-1000 cP.

2. The method for preparing fuel cell catalyst slurry according to claim 1, characterized in that, In step S3, the dispersion is carried out under high pressure, and the dispersion pressure of the high pressure dispersion is 10-70% of the dispersion pressure in step S1.

3. The method for preparing fuel cell catalyst slurry according to claim 1, characterized in that, The mass ratio of the surfactant to the carbon material is (0.1-2):1; the mass ratio of the ionomer to the catalyst is (0.1-1):

1.

4. The method for preparing fuel cell catalyst slurry according to any one of claims 1 to 3, characterized in that, The catalyst slurry contains 10-50 wt% low-boiling-point organic matter, the catalyst pre-dispersion slurry contains 5-30 wt% ionomers, and has a viscosity of 5-1000 cP.

5. The method for preparing fuel cell catalyst slurry according to claim 4, characterized in that, The catalyst is Pt / C or PtM / C, where M is Co, Fe, Ni, Cu, Au, Ag, Pd, Ir, or Ru.

6. A fuel cell catalyst slurry, characterized in that, It is prepared by any of the fuel cell catalyst slurry preparation methods according to claims 1-5.

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