Preparation method of fuel cell CCM

Abstract

The invention discloses a preparation method of a fuel cell CCM, which improves the durability of a cathode side, improves the antipole resistance of an anode side, comprehensively improves the durability of a membrane electrode, improves the safety of the fuel cell and prolongs the service life of the fuel cell. The preparation method comprises the following steps: S1, preparing cathode catalyst slurry: mixing a catalyst A and a catalyst B, adding deionized water, a perfluorosulfonic acid resin solution and alcohols, and dispersing to obtain cathode slurry; s2, preparation of anode catalyst slurry: mixing a catalyst C, a catalyst D and IrO2, adding deionized water, a perfluorosulfonic acid resin solution and alcohols, and dispersing to obtain the anode catalyst slurry; and S3, CCM preparation: spraying the slurry on two sides of a proton exchange membrane in an ultrasonic spraying manner, and preparing a target CCM after spraying and drying.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a method for preparing a fuel cell CCM. Background Art

[0002] The membrane electrode assembly (MEA) in the proton exchange membrane fuel cell is the core component of the fuel cell, which converts the chemical energy of the fuel into electrical energy through electrochemical reactions. The electrochemical reaction site in the membrane electrode is the catalyst coated membrane (CCM), and the electrochemical reactions of hydrogen and oxygen (air) are all completed on the CCM. The current CCM production process is: first prepare the catalyst into a slurry with appropriate particle size and uniform dispersion, and then spray, transfer or coat the slurry on both sides of the proton exchange membrane to form a CCM.

[0003] After the fuel cell system is shut down, the hydrogen on the anode side of the stack will gradually be consumed, and the air will gradually penetrate into the anode side to form a hydrogen-air interface. When the system is started again, a high potential will be formed on the cathode side, causing corrosion of the cathode carrier, which will have a destructive effect on the performance and life of the membrane electrode. In addition, during long-term or high-current density operation of the stack, due to the plate design or matching with the membrane electrode, the gas distribution is uneven, the gas supply is insufficient, or flooding occurs, causing the voltage of some membrane electrodes to be extremely low or become negative, and then reverse polarity occurs. Reverse polarity will not only cause corrosion of the catalyst carrier, but may even cause corrosion of the gas diffusion layer, and the damage caused is irreversible, greatly affecting the safety and life of the fuel cell system. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for preparing a fuel cell CCM, which improves the durability of the cathode side and at the same time improves the anti-reverse polarity ability of the anode side, comprehensively improves the durability of the membrane electrode, and improves the safety and service life of the fuel cell.

[0005] A method for preparing a fuel cell CCM, characterized in that it comprises the following steps:

[0006] S1. Preparation of cathode catalyst slurry: after mixing catalyst A and catalyst B, adding deionized water, perfluorosulfonic acid resin solution and alcohol to disperse and obtain cathode slurry, wherein catalyst A is a Pt / C catalyst whose carrier is a high specific surface area carbon black, and catalyst B is a Pt / C catalyst whose carrier is graphitized carbon black, wherein the mass percentage of Pt is 10-50%;

[0007] S2, anode catalyst slurry preparation, catalyst C, catalyst D, IrO2 after mixing, adding deionized water, perfluorosulfonic acid resin solution, alcohols after dispersion to obtain anode slurry, wherein catalyst A is a Pt / C catalyst carrier is a superconducting carbon black, catalyst D is a Pt / C catalyst carrier is graphitized carbon black, wherein the mass percentage of Pt is 20 to 80%;

[0008] S3, CCM preparation, spraying the slurry on both sides of the proton exchange membrane by ultrasonic spraying, and preparing the target CCM after spray drying.

[0009] It is further characterized by:

[0010] Steps S1 and S2 are performed simultaneously or successively;

[0011] In step S1, the carrier of catalyst A is one of high specific surface area carbon black, carbon nanotubes, and Vulcan carbon black, or a mixture of different types;

[0012] In step S2, the carrier of catalyst C is one of superconducting carbon black, Vulcan carbon black or carbon nanotubes or a mixture of different types;

[0013] The alcohol used in steps S1 and S2 is at least one of isopropanol, ethanol, propanol, tert-butanol or n-butanol solvents;

[0014] The slurry in steps S1 and S2 is obtained by at least one of mechanical stirring, ultrasonic dispersion, and high-speed shearing;

[0015] In step S1, the mass ratio of deionized water to alcohol is 1 to 3:1, and the mass ratio of the dry weight of the carbon after the catalyst A and the catalyst B are mixed to the perfluorosulfonic acid resin is 0.6 to 1.2:1;

[0016] In step S1, the solid content of the cathode slurry is 0.5-4%;

[0017] In step S2, the mass of IrO2 is 5-40% of the total mass of catalyst C and catalyst D;

[0018] In step S2, the mass ratio of deionized water to alcohol is 1 to 3:1, and the mass ratio of the mixed carbon of catalyst C, catalyst D, and IrO2 to the dry weight of perfluorosulfonic acid resin is 0.8 to 1.2:1;

[0019] In step S2, the solid content of the anode slurry is 0.5-3%;

[0020] In step S3, the frequency of the vibration head used for ultrasonic spraying is 40-120kHz, the height of the nozzle is 2-8cm, the flow rate is 0.2-1.0ml / min, the speed is 100-200mm / s, and the platform temperature is 70-110°C.

[0021] After adopting the above technical scheme, the cathode catalyst adopts a Pt / C catalyst with a pure graphitized carbon carrier, which will increase the internal resistance due to the anisotropy of graphite and reduce the electrochemical performance of the membrane electrode. By mixing it with a Pt / C catalyst of a high specific surface area carbon black type, it enhances the corrosion resistance of the carrier while ensuring the performance, thereby improving the durability of the catalyst; the anode catalyst introduces IrO2 while introducing a graphitized carbon carrier while ensuring the electrical conductivity, and the addition of IrO2 increases the anti-reverse polarity ability of the anode side; it improves the durability of the cathode side, while improving the anti-reverse polarity ability of the anode side, comprehensively improving the durability of the membrane electrode, and improving the safety and service life of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a comparison diagram of polarization curves of the embodiment of the present invention and the comparative example under air cooling conditions (pure dry gas of the anode and cathode);

[0023] Figure 2 This is a comparison diagram of the anti-reverse polarity performance of the embodiment of the present invention and the comparative example after adding the anti-reverse polarity catalyst;

[0024] Figure 3 It is a comparison diagram of polarization curves after durability test of catalyst carriers of the embodiments of the present invention and the comparative examples. DETAILED DESCRIPTION

[0025] A method for preparing a fuel cell CCM comprises the following steps:

[0026] S1. Preparation of cathode catalyst slurry: after mixing catalyst A and catalyst B, adding deionized water, perfluorosulfonic acid resin solution and alcohol to disperse and obtain cathode slurry, the solid content of the cathode slurry is 0.5-4%, wherein catalyst A is a Pt / C catalyst whose carrier is a high specific surface area carbon black, and catalyst B is a Pt / C catalyst whose carrier is graphitized carbon black, wherein the mass percentage of Pt is 10-50%;

[0027] The alcohol is at least one of isopropanol, ethanol, propanol, tert-butanol or n-butanol solvents;

[0028] When dispersing to obtain the cathode slurry, it is carried out by at least one of mechanical stirring, ultrasonic dispersion, and high-speed shearing;

[0029] The mass ratio of deionized water to alcohol is 1 to 3:1, and the mass ratio of the dry weight of carbon and perfluorosulfonic acid resin after the mixture of catalyst A and catalyst B is 0.6 to 1.2:1;

[0030] In a specific implementation, the carrier of catalyst A is one of high specific surface area carbon black, carbon nanotubes, Vulcan carbon black, or a mixture of different types;

[0031] S2, anode catalyst slurry preparation, catalyst C, catalyst D, IrO2 after mixing, adding deionized water, perfluorosulfonic acid resin solution, alcohols after dispersion to obtain anode slurry, the anode slurry solid content of the slurry is 0.5 ~ 3%, wherein the catalyst A is a carrier of superconducting carbon black Pt / C catalyst, catalyst D is a carrier of graphitized carbon black Pt / C catalyst, wherein the mass percentage of Pt is 20 ~ 80%, alcohol is at least one of isopropanol, ethanol, propanol, tert-butanol or n-butanol solvent;

[0032] The anode slurry is dispersed by at least one of mechanical stirring, ultrasonic dispersion, and high-speed shearing;

[0033] The mass of IrO2 is 5-40% of the total mass of catalyst C and catalyst D;

[0034] The mass ratio of deionized water to alcohol is 1-3:1, and the mass ratio of the mixed carbon of catalyst C, catalyst D, and IrO2 to the dry weight of perfluorosulfonic acid resin is 0.8-1.2:1;

[0035] In a specific implementation, the carrier of catalyst C is one of superconducting carbon black, Vulcan carbon black or carbon nanotubes, or a mixture of different types;

[0036] S3, CCM preparation, spray the slurry on both sides of the proton exchange membrane by ultrasonic spraying, the frequency of the vibrator used for ultrasonic spraying is 40-120kHz, the nozzle height is 2-8cm, the flow rate is 0.2-1.0ml / min, the speed is 100-200mm / s, the platform temperature is 70-110℃, and the target CCM is prepared after spraying and drying.

[0037] Example:

[0038] S1, catalyst A and catalyst B are mixed in a mass ratio of 1:1 to obtain a Pt / C catalyst, and then 24g of deionized water is added dropwise to the Pt / C catalyst, and manually stirred while adding dropwise to completely wet the catalyst with the deionized water, and then 24g of isopropanol and 1.2g of a 20% mass fraction Nafion solution (perfluorosulfonic acid resin solution) are added in sequence, and ultrasonic dispersion is performed, the ultrasonic power is 300W, the ultrasonic time is 10mins, and the ultrasonic temperature is 10°C. The obtained slurry is then dispersed for 20mins using a high-speed shearing machine to obtain a cathode slurry;

[0039] S2, catalyst C, catalyst D, and IrO2 are mixed in a mass ratio of 1:1:0.2 to obtain a Pt / C catalyst, 20 g of deionized water is added dropwise to the Pt / C catalyst, and manually stirred while adding dropwise to completely wet the catalyst with the deionized water, and then 20 g of isopropanol and 0.6 g of a 20% mass fraction Nafion solution (perfluorosulfonic acid resin solution) are added in sequence, and ultrasonic dispersion is performed, with an ultrasonic power of 300 W, an ultrasonic time of 10 mins, and an ultrasonic temperature of 10°C. The obtained slurry is then dispersed for 20 mins using a high-speed shearing machine to obtain an anode slurry;

[0040] The cathode slurry and the anode slurry were respectively sprayed on both sides of the proton exchange membrane by ultrasonic spraying, wherein the spraying head frequency was 48kHz, the nozzle height was 3cm, the flow rate was 0.8ml / min, the speed was 100mm / s, and the platform temperature was 90°C to produce the target CCM.

[0041] The comparative example is an MEA made of a single catalyst.

[0042] The polarization curves of the embodiment and the comparative example are compared in Figure 1 The overall performance of the membrane electrode of the embodiment is improved by about 3% compared with the comparative example.

[0043] The anti-reverse polarity performance of the embodiment and the comparative example after adding the anti-reverse polarity catalyst is compared. Figure 2 The comparative example entered the carbon corrosion stage after 20 minutes, while the anti-reverse polarity performance of the embodiment remained stable after 250 minutes.

[0044] The polarization curves of the catalyst carriers of the embodiment and the comparative example after durability test are compared. Figure 3 The comparative example completely failed after running 400 voltage cycles, while the performance of the embodiment decreased by less than 5% after running 800 cycles.

[0045] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0046] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a fuel cell CCM, characterized in that: It includes the following steps: S1. Preparation of cathode catalyst slurry: after mixing catalyst A and catalyst B, adding deionized water, perfluorosulfonic acid resin solution and alcohol to disperse and obtain cathode slurry, wherein catalyst A is a Pt / C catalyst whose carrier is a high specific surface area carbon black, and catalyst B is a Pt / C catalyst whose carrier is graphitized carbon black, wherein the mass percentage of Pt is 10-50%; S2, preparing anode catalyst slurry, after mixing catalyst C, catalyst D, and IrO2, adding deionized water, perfluorosulfonic acid resin solution, and alcohol, and dispersing to obtain anode slurry, wherein catalyst A is a Pt / C catalyst whose carrier is superconducting carbon black, and catalyst D is a Pt / C catalyst whose carrier is graphitized carbon black, wherein the mass percentage of Pt is 20-80%; S3, CCM preparation, spraying the slurry on both sides of the proton exchange membrane by ultrasonic spraying, and preparing the target CCM after spray drying.

2. The method for preparing a fuel cell CCM according to claim 1, characterized in that: Steps S1 and S2 are performed simultaneously or successively.

3. The method for preparing a fuel cell CCM according to claim 1, characterized in that: The carrier of catalyst A in step S1 is one of high specific surface area carbon black, carbon nanotubes, Vulcan carbon black or a mixture of different types.

4. The method for preparing a fuel cell CCM according to claim 1, characterized in that: The carrier of the catalyst C in step S2 is one of superconducting carbon black, Vulcan carbon black or carbon nanotubes or a mixture of different types.

5. The method for preparing a fuel cell CCM according to claim 1, characterized in that: The alcohol used in steps S1 and S2 is at least one of isopropanol, ethanol, propanol, tert-butanol or n-butanol solvents.

6. The method for preparing a fuel cell CCM according to claim 1, characterized in that: The slurry in steps S1 and S2 is obtained by at least one of mechanical stirring, ultrasonic dispersion and high-speed shearing.

7. The method for preparing a fuel cell CCM according to claim 1, characterized in that: In step S1, the mass ratio of deionized water to alcohol is 1 to 3:1, and the mass ratio of the dry weight of the carbon after the catalyst A and the catalyst B are mixed to the perfluorosulfonic acid resin is 0.6 to 1.2:1; In step S1, the solid content of the cathode slurry is 0.5-4%.

8. The method for preparing a fuel cell CCM according to claim 1, characterized in that: In step S2, the mass of IrO2 is 5-40% of the total mass of catalyst C and catalyst D.

9. The method for preparing a fuel cell CCM according to claim 1, characterized in that: In step S2, the mass ratio of deionized water to alcohol is 1 to 3:1, and the mass ratio of the mixed carbon of catalyst C, catalyst D, and IrO2 to the dry weight of perfluorosulfonic acid resin is 0.8 to 1.2:1; In step S2, the solid content of the anode slurry is 0.5-3%.

10. The method for preparing a fuel cell CCM according to claim 1, characterized in that: In step S3, the frequency of the vibration head used for ultrasonic spraying is 40-120kHz, the height of the nozzle is 2-8cm, the flow rate is 0.2-1.0ml / min, the speed is 100-200mm / s, and the platform temperature is 70-110°C.

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