CN115188972A

CN115188972A - Catalyst slurry, preparation method and application thereof, membrane electrode and fuel cell

Info

Publication number: CN115188972A
Application number: CN202211005348.0A
Authority: CN
Inventors: 王晓云; 徐鑫; 庞从武
Original assignee: Suzhou Ansteic Hydrogen Energy Technology Co ltd
Current assignee: Suzhou Ansteic Hydrogen Energy Technology Co ltd
Priority date: 2022-08-19
Filing date: 2022-08-19
Publication date: 2022-10-14

Abstract

The invention discloses a catalyst slurry, a preparation method and application thereof, a membrane electrode and a fuel cell. According to the invention, uniform and stable catalyst slurry is obtained through ultrasound, high-shear dispersion and high-pressure homogenization in sequence, then different functional auxiliaries are added to prepare cathode first catalyst layer slurry, cathode second catalyst layer slurry, anode first catalyst layer slurry and anode second catalyst layer slurry, and then the catalyst layer, the membrane electrode and the fuel cell which are in cathode and anode layer functional distribution are formed after spraying by using a spraying process, wherein the initial electrochemical active area ECSA can reach 67m ² The electrochemical performance of the membrane electrode after the aging performance test of the catalyst is almost not attenuated in the range of small and medium electric densities, and the reduction amplitude of the reverse pole performance is as low as 6mV@0.8A/cm ² Over the whole electric density rangeThe output electric power density in the enclosure is higher.

Description

Catalyst slurry, preparation method and application thereof, membrane electrode and fuel cell

Technical Field

The invention belongs to the technical field of fuel cells, and particularly relates to catalyst slurry, a preparation method and application thereof, a membrane electrode and a fuel cell.

Background

The Proton Exchange Membrane Fuel Cell (abbreviated as PEMFC in English and totally called Proton Exchange Membrane Fuel Cell in English) has the advantages of compact structure, high response speed, environmental friendliness and the like, and has wide application prospect and important practical significance as a clean power Cell in the transportation fields of heavy trucks, forklifts, public transportation and the like. The Membrane Electrode Assembly (abbreviated as MEA in english, and collectively referred to as Membrane Electrode Assembly in english) is a core Assembly in the PEMFC, and is prepared by forming and bonding a proton Membrane, a catalyst layer, a gas diffusion layer and other key raw materials.

The performance of the catalyst layer in the MEA is related to not only the intrinsic activity of the catalyst, but also the composition of the catalyst layer slurry, the process of the catalyst layer film formation, the microporous layer structure and distribution of the catalyst layer, and the like. The intrinsic reaction activity of the catalyst is mainly determined by the characteristics of the catalyst carbon carrier, the morphology, the crystal form and the distribution state of the noble metal. The catalyst layer slurry generally consists of a catalyst, an ionomer dispersion, a solvent system, and a functional additive. The film forming process of the catalyst layer mainly comprises spraying, direct coating and thermal transfer printing. Most membrane electrode production adopts uniform cathode and anode catalyst layers, but in the actual electrochemical reaction process, various reactant and generating object systems are in gradient distribution in each layer and interlayer structure of the MEA, and the matching of the uniformly distributed catalyst layers and the gradient distributed material systems can cause the problems of excessive use, waste and the like of precious metals and ionomers.

Therefore, how to develop the fuel cell membrane electrode with hierarchically and functionally distributed cathode and anode catalytic layers is an urgent problem to be solved by research and development personnel in the field.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention aims to provide a catalyst slurry, a preparation method and application thereof, a membrane electrode and a fuel cell.

In order to achieve the purpose and achieve the technical effect, the invention adopts the technical scheme that:

the catalyst slurry is prepared by carrying out a multiple dispersion process on an ionomer dispersion, a solvent, a catalyst, deionized water and a functional auxiliary agent.

A preparation method of catalyst slurry comprises the following steps:

s1: mixing the ionomer dispersion with a solvent, and performing tip ultrasound to obtain a first dispersion;

s2: mixing the first dispersion liquid with a catalyst, deionized water, a solvent and a functional auxiliary agent, and then carrying out high-speed shearing to obtain a second dispersion liquid;

s3: and mixing the second dispersion liquid with a solvent, and carrying out high-pressure homogenizing and shearing to obtain the required catalyst slurry.

Further, in step S1, the step of mixing the ionomer dispersion with a solvent, and performing tip ultrasound to obtain a first dispersion includes:

weighing a certain amount of ionomer dispersion, placing the ionomer dispersion in a closed stirring kettle, weighing a certain amount of solvent, and adding the solvent into the ionomer dispersion, wherein the mass ratio of the ionomer dispersion to the solvent is (0.1-10): 1, performing tip ultrasound by using tip ultrasound equipment at the circulating cooling water temperature of 5-10 ℃, wherein the frequency is 12-24kHz, the output power is 50% -90%, then treating the compound material for 10-30min, and uniformly mixing to obtain a first dispersion liquid.

Further, in step S2, mixing the first dispersion with the catalyst, deionized water, the solvent, and the functional assistant, and then performing high-speed shearing to obtain a second dispersion, the step of obtaining the second dispersion includes:

placing a first dispersion solution, a catalyst, deionized water, a solvent and a functional auxiliary agent in a closed stirring kettle, wherein the mass ratio of the first dispersion solution to the catalyst to the deionized water to the solvent to the functional auxiliary agent is (10-20): 1: (3-10): (10-25): (10-30), stirring the compound materials for 30-60min at the temperature of 18-30m/s by using a high-speed shearing process at the temperature of 5-10 ℃ of circulating cooling water, and uniformly mixing to obtain a second dispersion liquid.

Further, in step S3, the step of mixing the second dispersion with a solvent, and then performing high-pressure homogenizing and shearing to obtain the desired catalyst slurry includes:

placing the second dispersion liquid into a hopper of a high-pressure homogeneous dispersion device, and adding a solvent, wherein the mass ratio of the second dispersion liquid to the solvent is (1-10): 1, carrying out internal circulation shearing and dispersion for 5-20 times under the shearing pressure condition of 400-1300bar to obtain the required catalyst slurry, wherein the solid content of the slurry is 1-5wt%. .

The invention also discloses application of the catalyst slurry in preparation of a catalyst layer.

The invention also discloses a catalyst layer which is a cathode catalyst layer or an anode catalyst layer, the cathode catalyst layer includes a cathode first catalytic layer CCL1 and a cathode second catalytic layer CCL2, the anode catalyst layer includes an anode first catalytic layer ACL1 and an anode second catalytic layer ACL2, the cathode first catalytic layer CCL1 is made by spraying a catalyst slurry as described above onto one side of a proton exchange membrane, the functional auxiliary agent in the catalyst slurry of the cathode first catalyst layer CCL1 is one or a combination of more of cerium oxide, carbon-supported cerium oxide and iron-doped titanium dioxide, the cathode second catalytic layer CCL2 is made by spraying one catalyst slurry as described above onto the surface of the cathode first catalytic layer CCL1, the functional auxiliary agent in the catalyst slurry of the cathode second catalyst layer CCL2 is one or a combination of several of carbon nanospheres, carbon nanotubes and carbon nanofibers, the catalyst metal loading capacity in the cathode first catalytic layer CCL1 is not less than the catalyst metal loading capacity in the cathode second catalytic layer CCL2, the EW value of the ionomer in the cathode first catalytic layer CCL1 is not less than that of the ionomer in the cathode second catalytic layer CCL2, the anodic first catalytic layer ACL1 is made by spraying a catalyst slurry as described above onto the other side of the proton exchange membrane, the functional auxiliary agent in the catalyst slurry of the anode first catalyst layer ACL1 is one or the combination of polytetrafluoroethylene, graphite flake and graphite carbon, the anode second catalytic layer ACL2 is made by spraying one kind of catalyst slurry as described above onto the surface of the anode first catalytic layer ACL1, the functional auxiliary agent in the catalyst slurry of the anode second catalyst layer ACL2 is one or a combination of polytetrafluoroethylene, graphite flakes and graphite carbon.

The invention also discloses a membrane electrode which comprises a proton exchange membrane, wherein a cathode first catalytic layer CCL1 is arranged on one side of the proton exchange membrane, an anode first catalytic layer ACL1 is arranged on the other side opposite to the proton exchange membrane, a cathode second catalytic layer CCL2 is arranged on one surface, far away from the proton exchange membrane, of the cathode first catalytic layer CCL1, and an anode second catalytic layer ACL2 is arranged on one surface, far away from the proton exchange membrane, of the anode first catalytic layer ACL 1.

The invention also discloses a preparation method of the membrane electrode, which comprises the following steps:

s1: weighing a proper amount of ionomer dispersion, placing the ionomer dispersion in a closed stirring kettle, weighing a proper amount of solvent, adding the solvent into the ionomer dispersion, performing tip ultrasound by using tip ultrasound equipment at the circulating cooling water temperature of 5-10 ℃, treating the compound material for 10-30min at the frequency of 12-24kHz and the output power of 50% -90%, and uniformly mixing to obtain a first dispersion;

s2: placing the first dispersion liquid, a catalyst, deionized water, a solvent and a functional assistant in a closed stirring kettle, stirring the compound material for 30-60min under the condition of circulating cooling water temperature of 5-10 ℃ and high shear process condition of 18-30m/s, and uniformly mixing to obtain a second dispersion liquid;

s3: placing the second dispersion liquid into a hopper of a high-pressure homogenizing and dispersing device, adding a proper amount of solvent, and internally and circularly shearing and dispersing for 5-20 times under the shearing pressure of 400-1300bar to obtain catalyst slurry;

s4: spraying the catalyst slurry serving as cathode first catalyst layer slurry to one side of a proton exchange membrane by using ultrasonic spraying equipment to form a cathode first catalyst layer CCL1, wherein the height of a spray head is 20-30mm, the moving linear speed of the spray head is 150-200mm/s, the spraying pressure is 1-3bar, the spraying amount is 1-3mL/min, and the vacuum adsorption drying is carried out for 2-10min;

s5, repeating the steps S1-S4, and spraying the catalyst slurry serving as cathode second catalyst layer slurry on the surface of the cathode first catalyst layer CCL1 by using ultrasonic spraying equipment to form a cathode second catalyst layer CCL2;

s6: repeating the steps S1-S4, spraying the catalyst slurry serving as anode first catalyst layer slurry to the other side of the proton exchange membrane by using ultrasonic spraying equipment to form an anode first catalyst layer ACL1, wherein the height of a spray head is 20-30mm, the linear speed of the movement of the spray head is 150-200mm/S, the pressure of a spray nozzle is 1-3bar, the spraying amount is 1-3mL/min, and the catalyst slurry is subjected to vacuum adsorption and drying for 2-10min;

s7: and (5) repeating the steps S1-S4, and spraying the catalyst slurry serving as anode second catalytic layer slurry onto the surface of the anode first catalytic layer ACL1 by using ultrasonic spraying equipment to form an anode second catalytic layer ACL2.

The invention also discloses a fuel cell, which comprises the membrane electrode.

Further, in step S1, the ionomer dispersion is one or a combination of several of Nafion, aquivion, flemion, and Aciplex, and the solvent is one or a combination of several of deionized water, ethanol, n-propanol, isopropanol, ethylene glycol, and propylene glycol.

Further, in the step S2, the catalyst is one or a combination of several of Pt/C, ptCo/C, ptNi/C, ir/C, irRu/C, ptRu/C, the carrier of the catalyst is one or a combination of several of low specific surface porous carbon, medium specific surface porous carbon, high specific surface porous carbon and graphite carbon, and the solvent is one or a combination of several of ethanol, n-propanol, isopropanol, ethylene glycol and propylene glycol.

Further, in step S3, the solvent is one or a combination of several of ethanol, n-propanol, isopropanol, ethylene glycol, and propylene glycol.

Compared with the prior art, the invention has the beneficial effects that:

1) According to the invention, catalyst slurry with a uniform and stable system is obtained through tip ultrasound, high-shear dispersion (namely high-speed shear dispersion) and high-pressure homogeneous shear processes in sequence, then different functional auxiliaries are added to prepare cathode first catalyst layer slurry, cathode second catalyst layer slurry, anode first catalyst layer slurry and anode second catalyst layer slurry, and finally, a spraying process is used for spraying to form a catalyst layer, a membrane electrode and a fuel cell which are functionally distributed in a cathode-anode layer;

2) The carrier of the catalyst in the cathode first catalyst layer CCL1 is a high-specific-surface porous carbon carrier, and a proper amount of cerium oxide is added, so that the product can capture free radicals while achieving high electrochemical performance, and the attenuation of the chemical stability of the proton exchange membrane directly contacted with the cathode first catalyst layer CCL1 is further inhibited; meanwhile, the loaded noble metal catalyst particles obtained by the porous carbon carrier with high specific surface are fully and uniformly wrapped and mixed with the pre-dispersed ionomer macromolecules, the ionomer resin molecular chains are fully wound and crosslinked, liquid-solid phase dispersion liquid which is uniformly dispersed in a bulk phase can be obtained, and the obtained product is not easy to generate cracks, pinholes, bubbles and other appearance defects;

3) The carrier of the catalyst in the cathode second catalytic layer CCL2 adopts a porous carbon carrier with a medium specific surface, and a proper amount of carbon nano tubes with the length of 100-800nm are added, so that due to the cross-linking and steric hindrance effects of the inorganic carbon nano tubes with high length-diameter ratio and the organic ionomer, the catalytic layer forms a three-dimensional space structure, an effective three-phase interface is constructed, the internal mass transfer resistance is reduced, and the conductive property and the water drainage capability of the catalytic layer are enhanced;

4) The carrier of the catalyst in the anode first catalyst layer ACL1 adopts a graphitized carbon carrier, the catalyst adopts a Pt/C catalyst, and a polytetrafluoroethylene hydrophobic material is added, so that the effective water and gas drainage and guide functions of the catalyst layer are realized, and the medium-high-density mass transfer characteristic and the inverse pole tolerance characteristic are improved;

5) The carrier of the catalyst in the anode second catalyst ACL2 is a graphitized carbon carrier, and the catalyst is a supported Ir-based noble metal alloy catalyst, so that the effective water and gas drainage function of the catalyst layer is realized, and the anti-reversal performance of the membrane electrode is improved.

Drawings

FIG. 1 is a schematic structural view of a membrane electrode according to the present invention;

FIG. 2 is a 25cm assembled membrane electrode prepared in example 1 of the present invention and comparative example 1 ² A VI performance curve graph and an electric power density comparison graph of a single cell;

FIG. 3 shows a 25cm assembled membrane electrode prepared in example 1 of the present invention and comparative example 1 ² VI performance plots of single cells at the beginning of the catalyst performance testing process and after aging.

Detailed Description

The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and thus the scope of the present invention can be clearly and clearly defined.

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

As shown in fig. 1 to 3, a catalyst slurry is prepared by subjecting an ionomer dispersion, a solvent, a catalyst, deionized water and a functional assistant to a multiple dispersion process.

A preparation method of catalyst slurry comprises the following steps:

s1: weighing a certain amount of ionomer dispersion, placing the ionomer dispersion in a closed stirring kettle, weighing a certain amount of solvent, and adding the solvent into the ionomer dispersion, wherein the mass ratio of the ionomer dispersion to the solvent is (0.1-10): 1, performing tip ultrasound by using tip ultrasound equipment at the temperature of 5-10 ℃ of circulating cooling water, wherein the frequency is 12-24kHz, the output power is 50% -90%, then treating a compound material for 10-30min, and uniformly mixing to obtain a first dispersion liquid; the first dispersion liquid with the fully opened main chain of the ionomer can be obtained in a solvent system by using tip ultrasound, and after the main chain of the ionomer is fully opened, the defects of poor product performance consistency and the like caused by the ionomer aggregate in a cathode and anode catalyst layer are effectively avoided;

s2: placing the first dispersion liquid, a catalyst, deionized water, a solvent and a functional auxiliary agent in a closed stirring kettle, wherein the mass ratio of the first dispersion liquid to the catalyst to the deionized water to the solvent to the functional auxiliary agent is (10-20): 1: (3-10): (10-25): (10-30), under the condition of circulating cooling water temperature of 5-10 ℃, a high-speed mechanical shearing process is adopted, the compound material is stirred for 30-60min under the condition of 18-30m/s, and is uniformly mixed to obtain a second dispersion liquid, catalyst particles and ionomer resin molecules are fully mixed, uniformly wrapped and stably dispersed, and the ionomer molecules are effectively crosslinked, so that the distribution of a three-phase mass transfer interface of a catalyst layer is optimized, more catalytic active sites are exposed, the utilization rate of the catalyst is improved, the resistance of oxygen transmission is reduced, and the electrochemical performance and the power density of the product under high potential are improved;

s3: placing the second dispersion liquid into a hopper of high-pressure homogenizing and dispersing equipment, adding a solvent, and internally and circularly shearing and dispersing for 5-20 times under the pressure condition of 400-1300bar by adopting a high-pressure homogenizing and shearing process to obtain the required catalyst slurry, wherein the solid content of the slurry is 1-5wt%, and the mass ratio of the second dispersion liquid to the solvent is (1-10): 1.

the invention discloses application of the catalyst slurry in preparation of a catalyst layer.

A catalyst layer is a cathode catalyst layer or an anode catalyst layer, the cathode catalyst layer comprises a cathode first catalyst layer CCL1 and a cathode second catalyst layer CCL2, the anode catalyst layer comprises an anode first catalyst layer ACL1 and an anode second catalyst layer ACL2, the cathode first catalyst layer CCL1 is prepared by spraying one catalyst slurry to one side of a proton exchange membrane, a functional auxiliary agent in the catalyst slurry of the cathode first catalyst layer CCL1 is one or a combination of several of cerium oxide, carbon-supported cerium oxide and iron-doped titanium dioxide, the cathode second catalyst layer CCL2 is prepared by spraying one catalyst slurry to the surface of the cathode first catalyst layer CCL1, the functional auxiliary agent in the catalyst slurry of the cathode second catalyst layer CCL2 is one or a combination of several of carbon nanospheres, carbon nanotubes and carbon nanofibers, the metal loading capacity of the catalyst in the cathode first catalyst layer CCL1 is not less than the metal loading capacity of the catalyst in the cathode second catalyst layer CCL2, the EW value of the ionomer in the cathode first catalyst layer CCL1 is not less than the EW value of the ionomer in the cathode second catalyst layer CCL2, the anode first catalyst layer ACL1 is made by spraying the catalyst slurry to the other side of the proton exchange membrane, the functional auxiliary agent in the catalyst slurry of the anode first catalyst layer ACL1 is one or a combination of several of polytetrafluoroethylene, graphite flake and graphite carbon, the anode second catalyst layer ACL2 is made by spraying the catalyst slurry to the surface of the anode first catalyst layer ACL1, and the functional auxiliary agent in the catalyst slurry of the anode second catalyst layer ACL2 is one or a combination of several of polytetrafluoroethylene, graphite flake and graphite carbon.

The utility model provides a membrane electrode, including

proton exchange membrane

1, 1 one side of proton exchange membrane sets up the first catalytic layer CCL1 of negative pole, the one side that proton exchange membrane 1 was kept away from to the first catalytic layer CCL1 of negative pole is provided with negative pole second catalytic layer CCL2, the opposite side that proton exchange membrane 1 is relative is provided with the first catalytic layer ACL1 4 of positive pole, the one side that proton exchange membrane 1 was kept away from to the first catalytic layer ACL1 of positive pole is provided with positive pole second catalytic layer ACL 25, the one side that negative pole second catalytic layer CCL2 3 was kept away from the first catalytic layer CCL1 of negative pole is provided with negative pole gas diffusion layer 6, the one side that positive pole first catalytic layer ACL1 4 was kept away from to positive pole second catalytic layer ACL2 is provided with positive pole gas diffusion layer 7.

A method of making a membrane electrode comprising the steps of:

s1: weighing a certain amount of ionomer dispersion, placing the ionomer dispersion in a closed stirring kettle, weighing a certain amount of solvent, and adding the solvent into the ionomer dispersion, wherein the mass ratio of the ionomer dispersion to the solvent is (0.1-10): 1, performing tip ultrasound by using tip ultrasound equipment at the temperature of 5-10 ℃ of circulating cooling water, wherein the frequency is 12-24kHz, the output power is 50% -90%, then treating the compound material for 10-30min, and uniformly mixing to obtain a first dispersion liquid;

s2: placing the first dispersion liquid, a catalyst, deionized water, a solvent and a functional auxiliary agent in a closed stirring kettle, wherein the mass ratio of the first dispersion liquid to the catalyst to the deionized water to the solvent to the functional auxiliary agent is (10-20): 1: (3-10): (10-25): (10-30), stirring the compound materials for 30-60min under the condition of circulating cooling water temperature of 5-10 ℃ and high shear process condition of 18-30m/s, and uniformly mixing to obtain a second dispersion liquid;

s3: placing the second dispersion liquid into a hopper of a high-pressure homogeneous dispersion device, adding a solvent, and internally and circularly shearing and dispersing for 5-20 times under the shearing pressure condition of 400-1300bar to obtain the required catalyst slurry, wherein the solid content of the slurry is 1-5wt%, and the mass ratio of the second dispersion liquid to the solvent is (1-10): 1;

s4: spraying the catalyst slurry serving as cathode first catalyst layer slurry to one side of a proton exchange membrane 1 by using ultrasonic spraying equipment to form a cathode first catalyst layer CCL1, wherein the height of a spray head is 20-30mm, the moving linear speed of the spray head is 150-200mm/s, the spraying pressure is 1-3bar, the spraying amount is 1-3mL/min, and the vacuum adsorption drying is carried out for 2-10min;

s5, repeating the steps S1-S4, and spraying the catalyst slurry serving as cathode second catalytic layer slurry onto the surface of the cathode first catalytic layer CCL 12 by using ultrasonic spraying equipment to form a cathode second catalytic layer CCL2;

s6: repeating the steps S1-S4, spraying the catalyst slurry serving as anode first catalyst layer slurry to the other opposite side of the proton exchange membrane 1 by using ultrasonic spraying equipment to form an anode first catalyst layer ACL1, wherein the height of a sprayer is 20-30mm, the moving linear speed of the sprayer is 150-200mm/S, the pressure of the sprayer is 1-3bar, the spraying amount is 1-3mL/min, and the vacuum adsorption drying is carried out for 2-10min;

s7: repeating the steps S1-S4, and spraying the catalyst slurry serving as anode second catalyst layer slurry onto the surface of the anode first catalyst layer ACL1 4 by using ultrasonic spraying equipment to form an anode second catalyst layer ACL 2;

s8: a cathode gas diffusion layer 6 is provided on a surface of the cathode second catalytic layer CCL2 remote from the cathode first catalytic layer CCL2, and an anode gas diffusion layer 7 is provided on a surface of the anode second catalytic layer ACL2 remote from the anode first catalytic layer ACL1 5.

A fuel cell comprising a membrane electrode as described above.

In the step S1, the ionomer dispersion is one or a combination of several of commercial Nafion, aquivion, flemion, and Aciplex, and the solvent is one or a combination of several of deionized water, ethanol, n-propanol, isopropanol, ethylene glycol, and propylene glycol.

In the step S2, the catalyst is one or a combination of more of Pt/C, ptCo/C, ptNi/C, ir/C, irRu/C, ptRu/C, the carrier of the catalyst is one or a combination of more of low specific surface porous carbon, medium specific surface porous carbon, high specific surface porous carbon and graphite carbon, and the solvent is one or a combination of more of ethanol, n-propanol, isopropanol, ethylene glycol and propylene glycol.

In step S3, the solvent is one or a combination of several of ethanol, n-propanol, isopropanol, ethylene glycol and propylene glycol.

The metal loading of the catalyst in the first catalyst layer CCL1 of the cathode is 50-60%, the EW value of the ionomer dispersion is 800-1000g/mol, and the I/C ratio is (0.8-1.2): 1.

the metal loading of the catalyst in the cathode second catalyst layer CCL2 is 30-50%, the EW value of the ionomer dispersion is 1000-1200g/mol, and the I/C ratio is (0.5-1): 1.

the metal loading capacity of the catalyst in the anode first catalyst layer ACL1 is 20-30%, the EW value of the ionomer dispersion is 800-1000g/mol, and the I/C ratio is (1-1.5): 1.

the metal loading capacity of the catalyst in the anode second catalyst layer ACL2 is 20-30%, the EW value of the ionomer dispersion is 720-800g/mol, and the I/C ratio is (1-1.5): 1.

in steps S4 and S5, the total spraying loading amount of the cathode side catalyst slurry is 0.1-0.2mg/cm ² 。

In steps S6 and S7, the total spraying loading amount of the anode side catalyst slurry is 0.05-0.08mg/cm ² 。

Example 1

A preparation method of catalyst slurry comprises the following steps:

s1: weighing 5g of ionomer dispersion with an EW value of 800g/mol, placing the ionomer dispersion in a closed jacket stirring kettle, weighing 30g of isopropanol, adding the isopropanol into the ionomer dispersion, performing tip ultrasound by using tip ultrasound equipment at a circulating cooling water temperature of 5-10 ℃, treating the compound material for 20min with the frequency of 24kHz and the output power of 80%, and uniformly mixing to obtain a first dispersion;

s2: weighing 2.92g of catalyst, fully wetting and immersing the catalyst by using 10g of deionized water, then adding the catalyst and 40g of isopropanol into the first dispersion liquid together, placing the first dispersion liquid into a closed jacket stirring kettle, and stirring and uniformly mixing the compound material for 60min by using a high-speed mechanical shearing process under the condition of circulating cooling water at 0-5 ℃ under the condition of 22m/s to obtain a second dispersion liquid;

s3: and (3) placing the second dispersion liquid into a hopper of a high-pressure homogenizing and dispersing device, adding 44g of solvent, and internally circularly shearing and dispersing for 10 times under the shearing pressure of 500bar by adopting a high-pressure homogenizing and shearing process to obtain the catalyst slurry.

The utility model provides a membrane electrode, including

proton exchange membrane

1, 1 one side of proton exchange membrane sets up the first catalysis layer CCL1 of negative pole, the one side that proton exchange membrane 1 was kept away from to the first catalysis layer CCL1 of negative pole is provided with negative pole second catalysis layer CCL2, the opposite side that proton exchange membrane 1 is relative is provided with the first catalysis layer ACL1 of positive pole, the one side that proton exchange membrane 1 was kept away from to the first catalysis layer ACL1 of positive pole is provided with positive pole second catalysis layer ACL2, the one side that negative pole second catalysis layer CCL2 3 was kept away from the first catalysis layer CCL1 of negative pole is provided with negative pole gas diffusion layer 6, the one side that positive pole first catalysis layer ACL1 4 was kept away from to positive pole second catalysis layer ACL2 is provided with positive pole gas diffusion layer 7.

A method of making a membrane electrode comprising the steps of:

s2: weighing 2.92g of catalyst, fully wetting and immersing the catalyst by 10g of deionized water, then adding the catalyst and 40g of isopropanol into the first dispersion liquid, placing the first dispersion liquid and the first dispersion liquid into a closed jacket stirring kettle, and stirring and uniformly mixing the compound material for 60min under the condition of circulating cooling water at 0-5 ℃ by using a high-shear process under the condition of 22m/s to obtain a second dispersion liquid;

s3: placing the second dispersion liquid into a hopper of a high-pressure homogeneous dispersion device, and adding isopropanol, wherein the mass ratio of the second dispersion liquid to the isopropanol is (1-10): 1, internally circulating, shearing and dispersing for 10 times under the shearing pressure of 500bar to obtain catalyst slurry;

s4: spraying the catalyst slurry serving as cathode first catalyst layer slurry to one side of a proton exchange membrane 1 by using ultrasonic spraying equipment to form a cathode first catalyst layer CCL1, wherein the height of a spray head is 30mm, the moving linear speed of the spray head is 150mm/s, the spraying pressure is 1.5bar, the spraying amount is 1.5mL/min, and the vacuum adsorption drying is carried out for 5min;

s6: repeating the steps S1-S4, spraying the catalyst slurry serving as anode first catalyst layer slurry to the other side of the proton exchange membrane 1 by using ultrasonic spraying equipment to form an anode first catalyst layer ACL1, wherein the height of a spray head is 30mm, the moving linear speed of the spray head is 150mm/S, the pressure of the spray head is 1.5bar, the spraying amount is 1.5mL/min, and the catalyst slurry is subjected to vacuum adsorption and drying for 5min;

The formulations of the catalyst slurries used for the cathode first catalytic layer CCL1, the cathode second catalytic layer CCL2, the anode first catalytic layer ACL1, and the anode second catalytic layer ACL2 are shown in table 1.

TABLE 1

Example 2

The present example is different from example 1 in the parameters of the catalyst and ionomer used in the preparation method of the catalyst slurry of the present example, and the parameters of the catalyst and ionomer used in the preparation method of the catalyst slurry of example 2 are shown in table 2.

TABLE 2

The same as in example 1.

Example 3

The present example is different from example 1 in the parameters of the catalyst and ionomer used in the preparation method of the catalyst slurry in the present example, and the parameters of the catalyst and ionomer used in the preparation method of the catalyst slurry in example 3 are shown in table 3.

TABLE 3

The same as in example 1.

Example 4

The present example is different from example 1 in the parameters of the catalyst and the ionomer used in the method for preparing the catalyst slurry of the present example, and the parameters of the catalyst and the ionomer used in the method for preparing the catalyst slurry of example 4 are shown in table 1.

The same as in example 1.

TABLE 4

The sprayed amounts of the catalyst pastes of examples 1 to 4 are shown in Table 5.

TABLE 5

Comparative example 1

The present comparative example differs from example 1 in that the membrane electrode structure of the present comparative example does not contain the anode second catalytic layer ACL2, unlike example 1.

Comparative example 2

The present comparative example differs from example 1 in that the membrane electrode structure of the present comparative example does not contain the anode first catalytic layer ACL1 unlike example 1.

Comparative example 3

The present comparative example differs from example 1 in that the membrane electrode structure of the present comparative example does not contain the cathode second catalytic layer CCL2 unlike example 1.

Comparative example 4

The present comparative example is different from example 1 in that the membrane electrode structure of the present comparative example does not contain the cathode first catalytic layer CCL1 unlike example 1.

The membrane electrode structures of comparative examples 1 to 4 are shown in Table 6.

TABLE 6

The membrane electrode performance test scheme is as follows:

(1) High purity hydrogen (1.5L/min) was distributed to the anodes and air (2L/min) was distributed to the cathodes, with anode relative humidity set to 20%, cathode humidity set to 50%, anode stack pressure 80kpa, cathode stack pressure 70kpa, and stack temperature 75 ℃. And (3) loading to the maximum current, activating for 30min under constant current under the hydrogen-oxygen condition, then switching the cathode to air, and testing to obtain the initial VI performance of the membrane electrode after the voltage is stable for about 15 min.

(2) High-purity hydrogen (0.5L/min) is distributed into the anode and air (0.5L/min) is distributed into the cathode, the relative humidity of the anode is set to be 45%, the humidity of the cathode is set to be 45%, the pile-entering pressure of the anode is 50kpa, the pile-entering pressure of the cathode is 50kpa, the temperature of the galvanic pile is 60 ℃, and the initial ECSA of the membrane electrode is obtained through testing.

(3) High-purity nitrogen (1L/min) is distributed into an anode, air (1L/min) is distributed into a cathode, the relative humidity of the anode is set to be 90%, the humidity of the cathode is set to be 90%, the anode stacking pressure is normal pressure, the cathode stacking pressure is normal pressure, the temperature of an electric pile is 60 ℃, the sample is stopped after 40min of a counter-pole tolerance test, the VI performance of the sample is tested after 30min of dry gas purging of the cathode and the anode, and the counter-pole tolerance capacity is obtained by comparing the initial VI performance of a membrane electrode.

(4) High purity hydrogen (0.2L/min) was dispensed into the anode and nitrogen (0.075L/min) was dispensed into the cathode, setting the cathode and anode relative humidity to 100%, the cathode and anode stack pressure to atmospheric pressure, and the stack temperature to 80 ℃. And (3) performing square wave circulation for 3s under the voltage of 0.6V and 3s under the voltage of 0.95V, and performing a catalyst aging test, wherein BOL refers to the hydrogen/air VI polarization measurement result before the catalyst aging test is started, and EOL refers to the hydrogen/air VI polarization measurement result after the catalyst aging test is finished.

The performance results of the membrane electrodes prepared in examples 1 to 4 and comparative examples 1 to 4 are shown in table 7.

TABLE 7

As can be seen from fig. 2 and table 7, examples 1 to 4 all exhibited higher electrochemical initiation properties, aging properties and anti-reversal characteristics than comparative examples 1 to 4. In the functionalized membrane electrode prepared by the catalyst slurry, the electrochemical performance of the embodiment 1 can realize 0.755V @0.8A/cm ² 、0.561V@2A/cm ² And the membrane electrode with uniformly distributed catalytic layers prepared under the conventional condition, like comparative examples 1-4, has the electrochemical initial performance reduced by about 20-40mV@0.8A/cm ² 、60-70mV@2A/cm ² (ii) a The initial electrochemical active area ECSA of example 1 can reach 67m ² Compared with the comparative example 1, the electrochemical performance of the membrane electrode is almost not attenuated in the small and medium electric density range of the example 1, the membrane electrode has different performance attenuation in the whole electric density range, particularly in the large electric density range, the attenuation amplitude reaches 10-30mV, and the performance reduction amplitude of the example 1 is only 6mV@0.8A/cm under the reversed pole condition of 40min ² In comparative example 2, the anode did not have the anode first catalyst layer ACL1 4 and the hydrophobic toneWhen saving agent, the performance is reduced to 19mV@0.8A/cm ² The reduction of the reverse polarity performance is more than 3 times, and when the anode does not have the anode second catalyst layer ACL2, as in comparative example 1, the reduction of the reverse polarity performance is about 8 times.

As can be seen from FIG. 3, in example 1, the output electric power density was higher in the entire electric density range than in comparative example 1, and the peak power density of the output electric power density was 1.12W/cm ² And is improved by about 16 percent compared with the latter.

The parts or structures of the invention which are not described in detail can be the same as those in the prior art or the existing products, and are not described in detail herein.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes performed by the present invention or directly or indirectly applied to other related technical fields are also included in the scope of the present invention.

Claims

1. The catalyst slurry is characterized by being prepared by carrying out multiple dispersion technology on ionomer dispersion liquid, a solvent, a catalyst, deionized water and a functional auxiliary agent.

2. The method for preparing catalyst slurry according to claim 1, comprising the steps of:

3. The method of claim 2, wherein the step of mixing the ionomer dispersion with the solvent and performing the tip sonication to obtain the first dispersion in step S1 comprises:

4. The method for preparing catalyst slurry according to claim 2, wherein in step S2, the step of mixing the first dispersion with the catalyst, the deionized water, the solvent and the functional assistant, and then performing high-speed shearing to obtain the second dispersion comprises:

5. The method of claim 2, wherein the step S3 of mixing the second dispersion with a solvent and then subjecting the mixture to high-pressure homogeneous shearing to obtain the desired catalyst slurry comprises:

placing the second dispersion liquid into a hopper of a high-pressure homogeneous dispersion device, and adding a solvent, wherein the mass ratio of the second dispersion liquid to the solvent is (1-10): 1, carrying out internal circulation shearing and dispersion for 5-20 times under the shearing pressure condition of 400-1300bar to obtain the required catalyst slurry, wherein the solid content of the slurry is 1-5wt%.

6. Use of a catalyst ink according to claim 1 in the preparation of a catalyst layer.

7. A catalyst layer, characterized in that the catalyst layer is a cathode catalyst layer or an anode catalyst layer, the cathode catalyst layer comprises a cathode first catalyst layer CCL1 and a cathode second catalyst layer CCL2, the anode catalyst layer comprises an anode first catalyst layer ACL1 and an anode second catalyst layer ACL2, the cathode first catalyst layer CCL1 is prepared by spraying the catalyst slurry of claim 1 to one side of a proton exchange membrane, the functional auxiliary agent in the catalyst slurry of the cathode first catalyst layer CCL1 is one or a combination of several of cerium oxide, cerium oxide supported on carbon and iron-doped titanium dioxide, the cathode second catalyst layer CCL2 is prepared by spraying the catalyst slurry of claim 1 on the surface of the cathode first catalyst layer CCL1, the functional auxiliary agent in the catalyst slurry of the cathode second catalyst layer CCL2 is one or a combination of several of carbon nanospheres, carbon nanotubes and carbon nanofibers, the metal loading capacity of the catalyst in the cathode first catalytic layer CCL1 is not less than the metal loading capacity of the catalyst in the cathode second catalytic layer CCL2, the EW value of the ionomer in the cathode first catalytic layer CCL1 is not less than the EW value of the ionomer in the cathode second catalytic layer CCL2, the anode first catalytic layer ACL1 is prepared by spraying the catalyst slurry of claim 1 on the other side of the proton exchange membrane, the functional assistant in the catalyst slurry of the anode first catalytic layer ACL1 is one or a combination of several of polytetrafluoroethylene, graphite flake and graphite carbon, the anode second catalytic layer ACL2 is prepared by spraying the catalyst slurry of claim 1 on the surface of the anode first catalytic layer ACL1, the functional assistant in the catalyst slurry of the anode second catalytic layer ACL2 is polytetrafluoroethylene, graphite flake, and graphite flake, one or a combination of several of graphitic carbon.

8. The membrane electrode is characterized by comprising a proton exchange membrane, wherein a cathode first catalytic layer CCL1 is arranged on one side of the proton exchange membrane, an anode first catalytic layer ACL1 is arranged on the other side opposite to the proton exchange membrane, a cathode second catalytic layer CCL2 is arranged on one surface, far away from the proton exchange membrane, of the cathode first catalytic layer CCL1, and an anode second catalytic layer ACL2 is arranged on one surface, far away from the proton exchange membrane, of the anode first catalytic layer ACL 1.

9. A preparation method of a membrane electrode is characterized by comprising the following steps:

s5, repeating the steps S1-S4, and spraying the catalyst slurry serving as cathode second catalytic layer slurry onto the surface of the cathode first catalytic layer CCL1 by using ultrasonic spraying equipment to form a cathode second catalytic layer CCL2;

10. A fuel cell comprising a membrane electrode of claim 9.