CN114583227A

CN114583227A - Preparation method of multi-layer membrane electrode with complex structure based on ink-jet printing

Info

Publication number: CN114583227A
Application number: CN202210179477.5A
Authority: CN
Inventors: 李冰; 上官子轩; 明平文; 杨代军; 张存满
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2022-02-25
Filing date: 2022-02-25
Publication date: 2022-06-03

Abstract

The invention relates to a preparation method of a membrane electrode, in particular to a preparation method of a multi-layer complex structure membrane electrode based on ink-jet printing, which comprises the following steps: respectively preparing slurry of a layer to be printed, and carrying out pretreatment; respectively storing the pretreated slurry in slurry storage boxes; during ink-jet printing, the sizing agents stored in the sizing agent storage box are respectively printed on the printing base material in sequence through a plurality of nozzles to form a multilayer structure, and the multilayer structure is bonded to form the membrane electrode. Compared with the prior art, the membrane electrode manufactured by the invention has a stronger interface structure, and the durability of the membrane electrode can be effectively improved; meanwhile, the production process is simple, the scheme is more integrated, the thickness and the structure of each layer can be flexibly adjusted, and the membrane electrode proton exchange membrane, the catalyst layer and the microporous layer with the three-dimensional structure can be flexibly manufactured, so that the microstructure of the membrane electrode has stronger customization.

Description

Preparation method of multi-layer membrane electrode with complex structure based on ink-jet printing

Technical Field

The invention relates to a preparation method of a membrane electrode, in particular to a preparation method of a multi-layer complex-structure membrane electrode based on ink-jet printing.

Background

Under the complex backgrounds of deep adjustment of world energy pattern, acceleration of actions for global coping with climate change and continuous strengthening of resource and environment constraints, hydrogen energy is one of the major strategic directions of the recognized world energy and power transformation, so that the hydrogen energy is concerned by all countries in the world. Accelerating the development of the hydrogen energy industry, and being a strategic choice for China to cope with global climate change, practice the strategy of developing the Yangtze river economic zone, guarantee the national energy supply safety and realize sustainable development. The application of hydrogen energy is diversified, and comprises various modes such as a fuel cell, a gas turbine, a hydrogen internal combustion engine, common combustion and the like, wherein the fuel cell is one of the most important modes for applying the hydrogen energy at present. Since the fuel cell does not need to pass through the carnot cycle of a heat engine, the fuel cell has higher potential efficiency relative to an internal combustion engine, and meanwhile, nitrogen oxide emission generated by combustion does not exist, so that the fuel cell is the most ideal mode for utilizing hydrogen energy. The fuel cell is in the initial stage of commercial application, and faces the problems of short service life, high cost and the like, the manufacturing process of the membrane electrode assembly inside the fuel cell is very complex, and a complex preparation process is still needed to obtain a qualified product after various materials are prepared, so that the improvement on the production method of the membrane electrode is urgently needed, and a preparation process with wide application range and simple process is provided.

Through the literature search of the prior art, the research on the processing and optimization of raw materials used for manufacturing the membrane electrode in the production process of the membrane electrode of the proton exchange membrane fuel cell is mostly focused to improve the performance of the membrane electrode assembly. In the chinese patent "method for manufacturing a membrane-electrode assembly, a membrane-electrode assembly manufactured thereby and a fuel cell including the same" (publication No. CN109075348A), the kakkiso LG chemical proposes a method for manufacturing a membrane-electrode assembly, an assembly product manufactured using the method and a method for producing a fuel cell by the assembly, it is prepared by coating a mixture on a substrate by spraying or screen printing using a catalyst, a fluoropolymer ionomer, and a solvent such as water, methanol, and ethanol, the dried result is then transferred to one or both surfaces of an electrolyte membrane to form a catalytic layer, which re-homogenizes the catalyst slurry composition using ultrasonic technology, thus improving the dispersion of the ionomer, and the final performance of the fuel cell, but there is no disclosure of how to perform the specific operations of the spraying, printing, etc. preparation steps. The company dyhler, in chinese patent "method for manufacturing membrane electrode assemblies for fuel cells" (publication No. CN107851825A), proposed a method for achieving a certain degree of freedom in designing a membrane electrode assembly by applying catalyst layer raw materials onto an electrolyte membrane in the form of droplets using a non-contact printing method, which facilitates substantially continuous and inexpensive manufacture of the membrane electrode assembly.

Although there have been studies considering the fabrication of a membrane electrode using an ink jet printing technique, the contents of its application to ink jet printing are limited to a catalytic layer slurry containing a catalyst and an ionomer in the first place, and the printing of other components such as an electrolyte membrane is not considered; meanwhile, the printing mode is simple, only a single-layer catalytic layer with uniform plane direction is printed, and the possibility of patterned printing in the multilayer structure and the plane direction of the catalytic layer is not considered.

Disclosure of Invention

The invention aims to solve at least one of the problems, and provides a preparation method of a multi-layer membrane electrode with a complex structure based on ink-jet printing, which realizes the ink-jet printing of the whole membrane electrode, can realize the design and printing of a three-dimensional structure and a special structure of each layer, and the design and printing of a multi-layer catalyst layer, and realizes multifunctional application.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a multi-layer membrane electrode with a complex structure based on ink-jet printing comprises the following steps: respectively preparing slurry of a layer to be printed, and carrying out pretreatment; respectively storing the pretreated slurry in slurry storage boxes; during ink-jet printing, the sizing agents stored in the sizing agent storage box are respectively printed on the printing base material in sequence through a plurality of nozzles to form a multilayer structure, and the multilayer structure is bonded to form the membrane electrode.

Preferably, the layer to be printed is one or more of a proton exchange membrane, a catalytic layer, a microporous layer, a reinforcing layer and an adhesive layer.

Preferably, the layer to be printed is of a planar structure or a three-dimensional structure, so that a plurality of layers of membrane electrodes can be printed in sequence during printing, subsequent steps are omitted, and the production efficiency of the membrane electrodes is greatly improved; and a structure which is difficult to realize by a conventional method or a special structure with high precision can be designed in a printing mode, so that the performance of the fuel cell is improved.

Preferably, the structure of the layer to be printed is controlled by adjusting the amount of ink ejected (amount of ink ejected at each pixel point) and the ink ejection speed and the travel speed of the print head (head). Specifically, the ink-jet amount of each pixel site can be adjusted according to the design requirements of a printing pattern during ink-jet printing, so that the overall thickness of a layer to be printed can be flexibly adjusted; meanwhile, the ink jet speed and the printing head advancing speed can be adjusted, so that the drying rate and the drying time of the printed layer structure are controlled, the optimal membrane electrode design is obtained, and the plane layer structure with excellent performance is obtained; or the thickness of partial area can be adjusted to form a three-dimensional structure, so that the design of various structures is realized, and the requirement of actual performance is met.

Preferably, the catalytic layer is one or more layers. In other words, a plurality of sub-catalyst layers can be formed in the catalyst layer of the same membrane electrode according to the requirements of the membrane electrode, so that the problem that only one catalyst can be used in one conventional membrane electrode to manufacture one structure can be solved; meanwhile, the problems of low efficiency and difficult interface formation caused by the fact that the preparation of the next catalyst layer can be carried out only after the previous catalyst layer is dried in the traditional membrane electrode catalyst layer preparation technology can be solved, the membrane electrode preparation efficiency can be greatly improved, and the inner interface of the catalyst layer which is in more benign contact can be formed. In addition, different pore diameter structures and different hydrophilic and hydrophobic properties can be formed in the catalyst layers by the catalysts with different particle sizes and different functions, so that the three-phase interface structure of the catalyst layers can be reasonably regulated, the catalyst utilization rate and the power generation efficiency can be greatly improved, the utilization efficiency of the noble metal catalyst is improved, and the cost is effectively reduced.

Preferably, the material of the reinforcement layer may be expandable e-PTFE (expanded polytetrafluoroethylene). In addition, the material of the reinforcing layer can be any other porous polymer with reinforcing capacity, and an anti-pole material or ionomer can be added or coated on the surface to enhance proton conductivity.

Preferably, the enhancement layer is arranged on the surface of the catalytic layer or in the proton exchange membrane, and the enhancement layer is sprayed on the surface of the catalytic layer, so that the contact resistance of an interlayer interface between the two layers can be reduced, the bonding strength between the catalytic layer and the proton exchange membrane is increased, the bonding failure of the interlayer interface between the catalytic layer and the proton exchange membrane is prevented, and the integral durability of the membrane electrode is further improved. The design of the enhancement layer can be added in the process of ink-jet printing of the proton exchange membrane, namely after the first layer of ionomer resin material is ink-jet printed, the expandable e-PTFE (expanded polytetrafluoroethylene) enhancement layer is added on the surface of the first layer of ionomer resin material, and the ionomer resin material is sprayed and printed on the surface of the first layer of ionomer resin material, so that the proton exchange membrane with the enhancement layer is obtained.

Preferably, the anti-reversal material is iridium oxide, iridium ruthenium oxide (IrRuO)₂) And cerium oxide.

Preferably, the ionomer is perfluorosulfonic acid (PFSA) and/or polyvinylidene fluoride (PVDF).

Preferably, the bonding layer is arranged between the catalytic layer and the microporous layer, the bonding strength between the catalytic layer and the gas diffusion layer can be effectively increased through the arrangement of the bonding layer, the hydrophilicity and the hydrophobicity can be effectively improved, and the condition that a drainage channel is partially blocked due to the accumulation of liquid water caused by the existence of obvious gaps between the catalytic layer and the microporous layer is avoided.

Preferably, when the layer to be printed is a catalytic layer, the slurry is prepared by the following steps: dispersing the resin solution in a mixed solvent, and stirring in a vacuum container to obtain a dispersed solution; and ultrasonically dispersing the catalyst in the dispersion solution at constant temperature to obtain catalyst slurry.

Preferably, the catalyst includes fuel cell catalysts produced by manufacturers of noble metals in Manchu-Xinwan and Tian, and catalysts produced by other catalyst enterprises or membrane electrode manufacturers in various forms suitable for fuel cell membrane electrodes, such as: one or more of Hispec9100(JM), TEC10E50E (TKK), TEC10EA50E (TKK) and other catalyst brands.

Preferably, the resin solution comprises a resin of a first resin solution and a second resin solution, and the manufacturers thereof are Asahi glass, DuPont and Solvay, etc., such as: one or more of Nafion D520, Nafion D2020, Nafion D1020, Aquivion D79-25BS, Aquivion D83-24B and Aquivion D98-25BS, and the resin solution can be used for preparing the catalytic layer and can be added with an expandable e-PTFE layer, an anti-antipole material and the like to print the proton exchange membrane. Through the matched use of the resins of the first resin solution and the second resin solution, the resin with the required ion exchange equivalent can be customized.

Preferably, the anti-reversal material is iridium oxide or iridium ruthenium oxide (IrRuO)₂) And cerium oxide and the like.

Preferably, the mixed solvent comprises alcohols and deionized water; the alcohols include high boiling and low boiling alcohols such as: one or more of n-propanol, isopropanol, ethanol, ethylene glycol, n-butanol, tert-butanol and methanol.

Preferably, the stirring is carried out for 24 hours at 20-2500 rpm.

Preferably, the constant-temperature ultrasonic dispersion is ultrasonic dispersion carried out for 30min under the conditions of 17 ℃, the ultrasonic frequency of 25kHz and the ultrasonic power of 700W.

Preferably, the catalyst, the resin solution, the alcohol and the deionized water are mixed according to the mass ratio of (9-25): (3-10): (33-50): (30-45).

Preferably, when the layer to be printed is a proton exchange membrane, the slurry is prepared by the following steps: according to a weight ratio of 60 wt% Pt/C: 5 wt.%

Monomer solution: isopropyl alcohol: deionized water 8: 3: 38: 40, and ultrasonically dispersing (25 ℃) for 1 hour.

Preferably, the resin solution comprises a resin of a first resin solution and a second resin solution, and the manufacturers thereof are Asahi glass, DuPont and Solvay, etc., such as: one or more of Nafion D520, Nafion D2020, Nafion D1020, Aquivion D79-25BS, Aquivion D83-24B and Aquivion D98-25BS, and the resin solution can be used for adding an expandable e-PTFE layer, an anti-reversal electrode material and the like to print the proton exchange membrane and preparing a catalytic layer.

Preferably, when the layer to be printed is a microporous layer, the slurry is prepared by: according to the mass ratio of XC-72 carbon powder, PTFE, Nafion and isopropanol of 1-10: 0-1: 0-1: 10-30, preparing microporous layer slurry, and performing mechanical stirring and ultrasonic dispersion treatment to obtain the slurry.

Preferably, the ionomer is Nafion D520, Nafion D2020, Nafion D1020, Aquivion D79-25BS, Aquivion D83-24B, Aquivion D98-25 BS.

Preferably, when the layer to be printed is an adhesive layer, the slurry is prepared by the following steps: the resin solution was dispersed in the mixed solvent and stirred in a vacuum vessel to obtain an adhesive layer slurry.

Preferably, the resin solution comprises a resin of a first resin solution and a second resin solution, and the manufacturers thereof are Asahi glass, DuPont and Solvay, etc., such as: one or more of Nafion D520, Nafion D2020, Nafion D1020, Aquivion D79-25BS, Aquivion D83-24B, and Aquivion D98-25 BS.

Preferably, the stirring is carried out for 48 hours at 20-2500 rpm.

Preferably, the first resin solution, the second resin solution, the alcohol and the deionized water are mixed according to the mass ratio (1-2): (2-4): (33-45): (33-45).

Preferably, the solid content of the slurry is 0.1-5%, so that the structure and drying of the catalyst layer are controlled, and the better fuel cell performance is obtained.

Preferably, the pretreatment is one or more of vacuum defoaming, ultrasonic cavitation, low temperature stabilization and shear stabilization.

Preferably, the pretreatment time is 10-30 min, the temperature is 0-20 ℃, and the shearing rotating speed is 8000-20000 rpm.

Preferably, the printing substrate is one or more of a PTFE-based membrane, a microporous layer, a proton exchange membrane, a catalytic layer, and carbon paper. That is, the printing substrate, such as carbon paper, may be printed in the order of assembly of the fuel cell, the microporous layer may be printed on the surface thereof, the catalytic layer may be printed on the printed microporous layer, and the proton exchange membrane may be printed on the printed catalytic layer.

Preferably, the bonding is heat pressing or lamination.

Preferably, the hot pressing is carried out at 80-180 ℃ and 0-2.5 MPa; the lamination is carried out at normal temperature and under 0-2.5 MPa.

Preferably, for the above preparation method, the inkjet head used for inkjet printing includes a plurality of modules, each module may be juxtaposed with at least one inkjet head, and each module may set parameter changes according to different printing requirements, so as to implement patterned printing in a multilayer structure or in a planar direction, and have stronger customizability. By using a plurality of groups of ink-jet printing nozzles, a new enhancement layer or an adhesive layer can be ink-jet printed on the surface of the existing layer structure, the adjustment can be flexibly carried out according to the design requirement of the membrane electrode, and meanwhile, the production efficiency is ensured.

The membrane electrode process types adopted by printing comprise that a catalyst is directly coated on a proton exchange membrane, the catalyst is coated on a gas diffusion layer or different manufacturing methods are adopted for the cathode and the anode of the same membrane electrode according to different requirements. Specifically, the method includes but is not limited to the following methods:

step 1: first, catalyst paste, proton exchange membrane paste, a substrate for printing, i.e., a PTFE-based film, and a gas diffusion layer assembly required for assembling the MEA are prepared. In the printing process, firstly, the proton exchange membrane is printed on the PTFE base membrane, and whether an expandable e-PTFE reinforced layer is added into the PTFE base membrane or not can be selected according to requirements, so that the proton exchange membrane with the reinforced layer is prepared. The printing of the catalyst layer can be selected after the complete drying of the PEM (proton exchange membrane) or before the complete drying of the PEM, so that the better connection between the catalyst layer and the PEM can be realized. After the ink-jet printing of the proton exchange membrane and the catalytic layer is finished, the prepared gas diffusion layer and the ink-jet printing product can be subjected to hot pressing or laminating, so that the catalytic layer and the proton exchange membrane are integrally transferred, and then the PTFE base film is removed. For the other side electrode of the proton exchange membrane, a commercial gas diffusion electrode can be used, and ink-jet printing can be performed again (see step 3).

And a step 2: it is first necessary to prepare a slurry of catalyst and proton exchange membrane, prepare the PTFE substrate for printing, and prepare the gas diffusion layer assembly required for assembly of the MEA. In the printing process, firstly, the proton exchange membrane is printed on the surface of the PTFE base membrane, and whether an expandable e-PTFE reinforced layer is added can be selected to prepare the proton exchange membrane with the reinforced layer. The catalyst layer slurry is sprayed on the prepared gas diffusion layer to form better interface bonding between the catalyst layer and the microporous layer to form a gas diffusion electrode, and finally the proton exchange membrane prepared by ink-jet printing and the gas diffusion electrode prepared by spray printing are bonded together in a hot pressing or laminating mode according to the sequence of the gas diffusion electrode, the proton exchange membrane and the gas diffusion electrode.

Step 3: firstly, preparing catalyst slurry, preparing a gas diffusion layer to be used in advance, spraying the prepared catalyst slurry on the surface of a proton exchange membrane, wherein one surface can be selected for spraying, and then the other surface is sprayed; double-sided simultaneous spraying can also be selected to achieve higher yields. And drying after spraying, and finally carrying out hot pressing or laminating on the membrane electrode and the prepared gas diffusion layer to obtain the membrane electrode product.

And step 4: a microporous layer slurry is first prepared, and the already prepared CCM is required as a printing substrate, and the carbon paper to be used is prepared. And finally, carrying out hot pressing or laminating combination on the two sides of a product containing the proton exchange membrane, the cathode and anode catalyst layer and the cathode and anode microporous layer and carbon paper to finally obtain a membrane electrode product.

Step 5: first, catalyst slurry is prepared, and a proton exchange membrane to be used is prepared. Printing the catalyst layer slurry on the gas diffusion layer to respectively obtain cathode and anode gas diffusion electrodes, and carrying out hot pressing or laminating on the cathode and anode gas diffusion electrodes and the proton exchange membrane to finally obtain a membrane electrode product.

Step 6: firstly preparing a microporous layer, catalyst layer slurry and proton exchange membrane slurry, printing the microporous layer on a gas diffusion layer substrate, respectively printing a cathode catalyst layer and an anode catalyst layer, then respectively spraying partial proton exchange membranes on the surface of a cathode or anode catalyst layer, or on the surface of the cathode and anode catalyst layers, finally adding an expandable e-PTFE (polytetrafluoroethylene) enhancement layer in the middle, and finally hot-pressing or laminating the cathode and the anode together to form a membrane electrode product.

Step 7: preparing catalyst layer slurry, proton exchange membrane slurry and microporous layer slurry, performing ink-jet printing on substrate carbon paper, printing a microporous layer, printing a catalyst layer, and finally printing a proton exchange membrane, wherein the microporous layer and the catalyst layer are respectively printed on two pieces of carbon paper according to the requirements of a cathode and an anode, the proton exchange membrane part can be independently printed on the surface of the cathode or the anode catalyst layer according to the requirements, or simultaneously printed on the surfaces of the cathode and the anode catalyst layers, an expandable e-PTFE (polytetrafluoroethylene) enhancement layer is added, and finally performing hot pressing or laminating on the components to obtain a membrane electrode product.

Step 8: firstly, preparing catalyst layer slurry, proton exchange membrane slurry and microporous layer slurry, in the printing process, firstly, respectively carrying out ink-jet printing on the microporous layers on two pieces of carbon paper, and then, in the printing process, selecting one of the following three modes: 1. printing cathode and anode catalyst layers on the microporous layer, spraying and printing a proton exchange membrane on the PTFE base membrane, and then carrying out hot pressing or laminating to finally obtain a membrane electrode product; 2. firstly, ink-jet printing a proton exchange membrane on the surface of a PTFE (polytetrafluoroethylene) base membrane, then ink-jet printing a cathode-anode catalyst layer on the proton exchange membrane for two times or simultaneously, and then carrying out hot pressing or laminating on the cathode-anode catalyst layer and carbon paper sprayed with a microporous layer to finally obtain a membrane electrode product; 3. firstly, ink-jet printing is carried out on a proton exchange membrane on the surface of a PTFE base membrane, then one layer of a cathode-anode catalyst layer is ink-jet printed on a microporous layer, the other layer of the cathode-anode catalyst layer is ink-jet printed on the proton exchange membrane, or one part of the cathode-anode catalyst layer is spray-coated on the microporous layer, the other part of the cathode-anode catalyst layer is spray-coated on the proton exchange membrane, and finally, the obtained assembly is hot-pressed or laminated to obtain a membrane electrode product.

The above steps can be mixed, for example, the

steps

1 and 2 can be mixed, and when the step 1 is used, a part of the catalyst layer is simultaneously printed on the gas diffusion layer by ink jet; or in the step 2, partial catalyst layers are simultaneously ink-jet printed on the proton exchange membrane after ink-jet printing, so that a better bonding state between the layers is formed in the membrane electrode. Therefore, the same process combination method can carry out the permutation and combination of indefinite quantity and indefinite sequence on each process method, can greatly realize the flexibility of the process, provides great possibility for the development of the membrane electrode process of the fuel cell, and aims to realize the optimization of the performance and the service life of the membrane electrode of the fuel cell.

The invention is different from the original fuel cell membrane electrode in the ink-jet printing mode, and the selection of the type of the ink-jet printing equipment is that the membrane electrode catalytic layer or the microporous layer is prepared by ink-jet and spraying, the used printing head is only provided with one ink outlet, and the dispersing measures such as ultrasonic atomization and the like are added to the ink-jet printing outlet to ensure that the sprayed ink has larger dispersibility, so that the regulation and control of the ink-jet quantity of the pixel points can not be accurately realized. The ink-jet printing equipment used by the invention can be various daily-used printing equipment, in the printing process, the ink is directly dripped from the outlet and printed on the surface of the base material, ultrasonic dispersion is not carried out at the position of the spray head, the ink amount of different printed pixel sites can be accurately controlled, and the specific resolution depends on the printing parameters, the ink viscosity and other indexes.

One of the greatest advantages brought by the invention is that the thickness of each layer in different areas can be accurately adjusted through high-precision pixel sites of ink-jet printing, so that a more complex three-dimensional layer structure and a more complex three-dimensional structure of corresponding interlayer interface contact are brought.

Regarding the proton exchange membrane, the proton exchange membrane and the interlayer interface of the catalyst layer, the proton exchange membrane produced by the ink-jet printing method can be three-dimensional in surface and can be accurately designed into various shapes including punctiform, grooved, random array-shaped grooves and bulges, so that the surface area of the interlayer interface can be effectively increased, the content of the catalyst directly and really contacting the proton exchange membrane in the catalyst layer can be increased, the proton transfer efficiency of the catalyst layer is improved, and the catalyst utilization rate of the catalyst layer is effectively improved.

Similarly, for the interlaminar interfaces of the catalytic layer, the catalytic layer and the microporous layer, grooves and bulges which are dotted, arranged in grooves and immediately arrayed are formed, so that the contact surface area of the interlaminar interface can be effectively increased, a three-dimensional structure can be combined with hydrophilicity and hydrophobicity, and more hydrophobic materials are added to the protruded parts of the microporous layer to be used as gas channels penetrating into the catalytic layer; more hydrophilic materials or less hydrophobic materials are added into the concave part of the microporous layer, so that the directional discharge of liquid water in the catalytic layer is facilitated, and a drainage channel of the liquid water is formed.

In the invention, various pre-prepared sizing agents are stored in a storage box with an ultrasonic environment (through an ultrasonic device arranged in the storage box), and the dispersion state is kept, so that the stability of the sizing agents is kept, and meanwhile, the fluidity of the sizing agents can be kept, so that the coagulation of the sizing agents in a pipeline of an ink-jet printing system is avoided; the ink can be continuously sprayed in a dispersed state in the spraying process, so that the printing accuracy is ensured. And by adjusting the proportion of various sizing agents, the stability of ink discharge in the printing process can be improved on the basis of ensuring the dispersibility and stability of the sizing agents.

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

1. by adopting the preparation method of the multi-layer membrane electrode with the complex structure, provided by the invention, the performance of the product can be controlled and optimized by controlling the design scheme, the configured slurry and the set operating parameters adopted by ink-jet printing, the multi-layer structure of the catalyst layer can be realized, the membrane electrode manufacturing process can be flexibly selected, whether single layer or multiple layers are transferred or not can be selected, the membrane electrode production process with higher performance can be effectively developed, and the preparation method is suitable for batch production and manufacturing.

2. The preparation method can print the catalyst layer containing the plurality of sub-catalyst layers, so that different catalysts, dispersion solutions and resins can be used in the same membrane electrode catalyst layer, and the problem that one membrane electrode can only be used for manufacturing one structure is effectively solved. In addition, different pore diameter structures and even different hydrophilicity and hydrophobicity of the catalysts with different particle sizes can be formed in the catalyst layer, the three-phase interface structure of the catalyst layer can be reasonably regulated, the catalyst utilization rate is improved, the power generation efficiency is improved, and the cost is reduced.

3. The combination between the catalytic layer and the diffusion layer of the conventional membrane electrode is realized only by a hot pressing mode, the bonding strength is low, and the diffusion layer can fall off in the assembly and transfer process or the membrane swells in the long-term durability test process. The invention can use a plurality of groups of spray heads, and immediately spray another layer after one layer is sprayed, no matter whether the substrate is completely dried or not, because the new layer of material is directly formed on the surface of the original material substrate, the material particles can fully interact in the drying process, and a better interlayer combination result is formed; if the base material such as the proton exchange membrane is not completely dried, the spraying work of the catalyst layer is carried out, more catalyst particles can be permeated into the surface layer of the proton exchange membrane, the transition uniformity of the interface between the catalyst layer and the proton exchange membrane is improved, and the bonding strength of the interface between the layers is increased. The method can improve the bonding strength of the interlayer interface between layers in the membrane electrode and the durability of the membrane electrode in the working process.

4. The invention can obtain various plane structures or three-dimensional structures by adjusting the parameters of ink-jet printing, can easily realize the structures which are difficult to realize or even can not be realized in the conventional preparation method, and can select the optimized design for printing according to different performance requirements so as to improve the performance of the fuel cell.

5. When the invention is used for preparing the membrane electrode, the flow can be adjusted and combined according to the actual situation, only one layer can be printed, or a plurality of layers can be printed in sequence to obtain the membrane electrode assembly.

6. The membrane electrode prepared by the method has a stronger interface structure, and the durability of the membrane electrode can be effectively improved; meanwhile, the production process is simple, the scheme is integrated more, the thickness and the structure of each layer can be flexibly adjusted, and the membrane electrode proton exchange membrane, the catalysis layer and the microporous layer with the three-dimensional structure can be flexibly manufactured, so that the microstructure of the membrane electrode has stronger customization and controllability.

7. The interface is a naturally existing contact structure between the membrane electrode layer and the layer structure of the fuel cell, the interface is formed in the existing membrane electrode preparation technology, the interface is usually directly contacted by laminating or hot pressing of two prepared layer structures, and the original roughness and particles between microstructures of the interface can cause poor contact of the layer interface. However, the method of the invention uses ink-jet printing, which can keep partial wet state of the ink when contacting with the substrate, so that the newly printed layer structure can directly contact with the surface of the original layer under the rheological or denaturable state, thereby adapting to the roughness and the particulate matters of the surface, further leading the interlayer interface formed by the method to contact more closely from the microscopic angle, and partially increasing the actual contact surface area between the layers.

Drawings

FIG. 1 is a schematic flow diagram of a membrane electrode preparation process of the present invention;

FIG. 2 is a schematic view when printing is performed;

FIG. 3 is a schematic illustration of a portion of the printing capability achievable by the present invention;

FIG. 4 is a schematic illustration of the scope of use of the present invention;

FIG. 5 is a schematic structural diagram of a multi-layer complex-structure catalytic layer obtained by printing according to the present invention;

FIG. 6 is a schematic illustration of the ink jet printing process of step 1 provided by the present invention;

FIG. 7 is a schematic illustration of the ink jet printing process of step 2 provided by the present invention;

FIG. 8 is a schematic illustration of the ink jet printing process of step 3 provided by the present invention;

FIG. 9 is a schematic illustration of the ink jet printing process of step 4 provided by the present invention;

FIG. 10 is a schematic illustration of an ink jet printing process of step 5 provided by the present invention;

FIG. 11 is a schematic illustration of an ink jet printing process of step 6 provided by the present invention;

FIG. 12 is a schematic illustration of the ink jet printing process of step 7 provided by the present invention;

FIG. 13 is a schematic illustration of an ink jet printing process of process 8 provided by the present invention;

FIG. 14 is a graph showing the performance of the membrane electrode prepared in example 1 and the conventional membrane electrode prepared in comparative example;

in the figure: 1-a proton exchange membrane; 2-a catalytic layer; 3-a microporous layer; 4-carbon paper; 5-PTFE base film.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

In the following examples, as shown in fig. 1, an object to be printed is first determined based on fig. 3 and 4 before starting production, and design of a printing structure and selection of raw materials (raw material for disposing a paste, printing base material, and material prepared in advance) are performed. After the slurry of each layer is configured and pretreated, printing is carried out according to a selected printing process, as shown in fig. 2, and the membrane electrode is obtained after hot pressing or laminating.

The membrane electrode process types adopted by printing comprise that a catalyst is directly coated on the proton exchange membrane 1, the catalyst is coated on a gas diffusion layer or different manufacturing methods are adopted for the cathode and the anode of the same membrane electrode according to different requirements. Specifically, the method includes but is not limited to the following methods:

step 1: as shown in fig. 6, a catalyst paste, a slurry for a proton exchange membrane 1, a substrate for printing, i.e., a PTFE-based film 5, and a gas diffusion layer assembly required for assembling an MEA are prepared first. In the printing process, the proton exchange membrane 1 is firstly printed on the PTFE base membrane 5, and whether an expandable e-PTFE reinforcing layer is added to the PTFE base membrane can be selected according to requirements, so as to prepare the proton exchange membrane 1 with the reinforcing layer. The printing of the catalyst layer 2 can be selected after the PEM (proton exchange membrane 1) is completely dried or before the PEM is completely dried, so as to realize better connection between the catalyst layer 2 and the PEM. After the inkjet printing of the proton exchange membrane 1 and the catalytic layer 2 is finished, the prepared gas diffusion layer and the inkjet printed product may be hot-pressed or laminated, so that the catalytic layer 2 and the proton exchange membrane 1 are integrally transferred, and then the PTFE base film 5 is removed. For the other side electrode of the proton exchange membrane 1, a commercial gas diffusion electrode can be used, and ink-jet printing can be performed again (see step of process 3).

Step 2: as shown in fig. 7, it is first necessary to prepare a slurry of the catalyst and proton exchange membrane 1, prepare the PTFE substrate for printing, and prepare the gas diffusion layer assembly required for assembly of the MEA. In the printing process, the proton exchange membrane 1 is firstly printed on the surface of the PTFE base membrane 5, and whether an expandable e-PTFE reinforcing layer is added can be selected to prepare the proton exchange membrane 1 with the reinforcing layer. The catalyst layer 2 slurry is sprayed on the prepared gas diffusion layer to form a better catalyst layer 2/microporous layer 3 interlayer interface bonding to form a gas diffusion electrode, and finally the proton exchange membrane 1 prepared by ink-jet printing and the gas diffusion electrode prepared by spraying printing are bonded together in a hot pressing or laminating mode according to the sequence of the gas diffusion electrode-proton exchange membrane 1-gas diffusion electrode.

Step 3: as shown in fig. 8, firstly, catalyst slurry is prepared, a gas diffusion layer to be used is prepared in advance, the prepared catalyst slurry is sprayed on the surface of the proton exchange membrane 1, one surface of the proton exchange membrane can be selected to be sprayed, and then the other surface of the proton exchange membrane is sprayed; double-sided simultaneous spraying can also be selected to achieve higher yields. And drying after spraying, and finally carrying out hot pressing or laminating on the membrane electrode and the prepared gas diffusion layer to obtain the membrane electrode product.

And step 4: as shown in fig. 9, a microporous layer 3 slurry is first prepared, and the already prepared CCM is required as a printing substrate, and a carbon paper 4 to be used is prepared. And spraying the slurry of the microporous layer 3 on the surface of the prepared catalytic layer 2, wherein one side can be sprayed sequentially, and the two sides can be sprayed simultaneously, and finally, hot-pressing or laminating the two sides of the product containing the proton exchange membrane 1, the cathode and anode catalytic layer 2 and the cathode and anode microporous layer 3 with carbon paper 4 to obtain the membrane electrode product.

Step 5: as shown in fig. 10, a catalyst slurry is first prepared, and a proton exchange membrane 1 to be used is prepared. Printing the catalyst layer 2 slurry on the gas diffusion layer to respectively obtain cathode and anode gas diffusion electrodes, and performing hot pressing or laminating with the proton exchange membrane 1 to finally obtain a membrane electrode product.

Step 6: as shown in fig. 11, firstly, preparing a microporous layer 3, a catalyst layer 2 slurry and a proton exchange membrane 1 slurry, printing the microporous layer 3 on a gas diffusion layer substrate, and respectively printing a cathode catalyst layer and an anode catalyst layer 2, then, selectively and respectively spraying a part of the proton exchange membrane 1 on the surface of the cathode catalyst layer or the anode catalyst layer 2, or on the surface of the cathode catalyst layer and the anode catalyst layer 2, finally, adding an expandable e-PTFE reinforcement layer in the middle, and finally, hot-pressing or laminating the cathode and the anode together to form a membrane electrode product.

Step 7: as shown in fig. 12, firstly preparing a catalyst layer 2 slurry, a proton exchange membrane 1 slurry and a microporous layer 3 slurry, performing ink-jet printing on a substrate carbon paper 4, firstly printing a microporous layer 3, then printing a catalyst layer 2, and finally printing a proton exchange membrane 1, wherein the microporous layer 3 and the catalyst layer 2 are respectively printed on two carbon papers 4 according to the requirements of a cathode and an anode, the proton exchange membrane 1 can be independently printed on the surface of the cathode or the anode catalyst layer 2 according to the requirements, or simultaneously printed on the surfaces of the cathode and the anode catalyst layers 2, and an expandable e-PTFE reinforcing layer is added, and finally performing hot pressing or laminating on the above components to obtain a membrane electrode product.

Step 8: as shown in fig. 13, it is first necessary to prepare a catalyst layer 2 slurry, a proton exchange membrane 1 slurry, and a microporous layer 3 slurry, and in the printing process, the microporous layer 3 is first ink-jet printed on two pieces of carbon paper 4, and the following printing process can select one of the following three ways: 1. the cathode and anode catalyst layers 2 are printed on the microporous layer 3, the proton exchange membrane 1 is sprayed and printed on the PTFE base membrane 5, and then hot pressing or laminating is carried out to obtain a membrane electrode product; 2. firstly, ink-jet printing is carried out on a proton exchange membrane 1 on the surface of a PTFE base membrane 5, then a cathode-anode catalyst layer 2 is ink-jet printed on the proton exchange membrane 1 for two times or simultaneously, and then the proton exchange membrane is hot-pressed or laminated with carbon paper 4 coated with a microporous layer 3 to finally obtain a membrane electrode product; 3. firstly, ink-jet printing is carried out on a proton exchange membrane 1 on the surface of a PTFE base membrane 5, then one layer of cathode and anode catalyst layers 2 is ink-jet printed on a microporous layer 3, the other layer of cathode and anode catalyst layers is ink-jet printed on the proton exchange membrane 1, or one part of a cathode or anode catalyst layer 2 is sprayed on the microporous layer 3, the other part of the cathode or anode catalyst layer is sprayed on the proton exchange membrane 1, and finally, the obtained assembly is subjected to hot pressing or laminating to obtain a membrane electrode product.

The above steps may be mixed, for example, the

steps

1 and 2 may be mixed, and when the step 1 is used, the partial catalyst layer 2 is ink-jet printed on the gas diffusion layer; or in the step 2, partial catalyst layer 2 is simultaneously ink-jet printed on the proton exchange membrane 1, so that the better bonding state between the layers is formed in the membrane electrode. Therefore, the same process combination method can carry out the permutation and combination of indefinite quantity and indefinite sequence on each process method, can greatly realize the flexibility of the process, provides great possibility for the development of the membrane electrode process of the fuel cell, and aims to realize the optimization of the performance and the service life of the membrane electrode of the fuel cell.

The materials used in the following examples and comparative examples may be conventional commercially available products available to those skilled in the art, unless otherwise specified.

Example 1

A CCM method is selected to manufacture the membrane electrode, three spray heads are selected, and the hydrophilic catalyst layer 2, the hydrophobic catalyst layer 2 and the bonding layer are respectively sprayed on the proton exchange membrane 1. Selecting catalyst Hispec9100(JM) and catalyst TEC10E50E (TKK), and selecting resin Nafion D520 and resin Nafion D2020.

Preparing catalyst slurry A:

dispersing resin A (Nafion D520 ionomer solution) in a mixed solvent by magnetic stirring, wherein the mixed solvent consists of isopropanol and deionized water, and placing the mixture in a container which can be vacuumized and stirring for 24 hours to prepare a dispersed solution; wherein, the resin Nafion D520 ionomer solution comprises the following components in percentage by mass: isopropyl alcohol: deionized water 5: 40: 40, mixing the catalyst A with the dispersion solution, starting a constant-temperature water bath of an ultrasonic dispersion machine, setting the temperature to be 17 ℃, the ultrasonic frequency to be 25kHz and the power to be 700W, and performing ultrasonic dispersion for 30min to obtain catalyst slurry A; wherein, the catalyst Hispec9100(JM) is as follows according to mass ratio: resin Nafion D520 monomer solution: isopropyl alcohol: deionized water 10: 5: 40: 40.

preparing catalyst slurry B:

stirring and dispersing resin B (Nafion D2020 ionomer solution) in a mixed solvent, wherein the mixed solvent consists of two components of n-propanol and deionized water, and placing the mixed solvent in a container which can be vacuumized and stirring the mixed solvent for 24 hours to prepare a dispersed solution; wherein, the resin Nafion D2020 ionomer solution comprises the following components in percentage by mass: n-propanol: deionized water 6: 35: 45, mixing the catalyst B with the dispersion solution, starting a constant-temperature water bath of an ultrasonic dispersion machine, setting the temperature to be 17 ℃, the ultrasonic frequency to be 25kHz and the power to be 700W, and performing ultrasonic dispersion for 30min to prepare catalyst slurry B; wherein, according to the mass ratio, the catalyst B: resin Nafion D2020 ionomer solution: n-propanol: deionized water 9: 6: 35: 45.

preparing adhesive layer slurry:

dispersing a resin Nafion D2020 ionomer solution and a resin Aquivion D79-25BS ionomer solution in a mixed solvent by magnetic stirring, wherein the mixed solvent consists of ethanol and deionized water, and placing the mixture in a container which can be vacuumized and stirring for 48 hours to prepare a dispersed solution; wherein, the resin Nafion D2020 ionomer solution comprises the following components in percentage by mass: resin Aquivion D79-25BS ionomer solution: ethanol: deionized water 2: 2: 40: 40.

and (3) carrying out pretreatment before spraying on the prepared three kinds of slurry by adopting a vacuum defoaming process.

Catalyst slurry A, catalyst slurry B and adhesive layer slurry are respectively placed in three slurry storage boxes, as shown in figure 2, a spraying program is set, a first catalyst layer 2 (catalyst slurry A) is sprayed when the catalyst slurry A is close to a proton exchange membrane 1, as shown in figure 5 (the first catalyst layer 5 in the figure is a sphere at the lower layer), a hydrophilic catalyst layer 2 is formed, and the wettability of the proton exchange membrane 1 can be effectively enhanced in the power generation process of the catalyst layer 2; next, spraying a second catalyst layer 2 (catalyst slurry B) on the first catalyst layer 2, as shown in fig. 5 (in the figure, the second catalyst layer 5 is a sphere at the upper layer), so as to form a hydrophobic catalyst layer 2, enhance the water drainage capability of the catalyst layer 2, and prevent the flooding problem in the operation process; and finally, spraying a layer of bonding layer slurry on the second catalyst layer 2, wherein the bonding layer slurry is free of catalyst and is only low-density mixed dispersion liquid of two kinds of resins, the bonding strength between the catalyst layer 2 and the diffusion layer at the later stage can be effectively increased by adding the bonding layer, the hydrophilicity and hydrophobicity of the membrane electrode can be further improved by mixing the two kinds of resins, and an obvious hydrophilic interface can not appear, so that the local blockage of a drainage channel of the catalyst layer 2 and the diffusion layer is caused.

And taking down the sprayed CCM, and carrying out hot pressing on the CCM and a diffusion layer prepared in advance to form the target membrane electrode.

Example 2

Selecting the process 7 to prepare the slurry of the microporous layer 3, the catalyst layer 2 and the proton exchange membrane 1, and sequentially preparing the microporous layer 3, the catalyst layer 2 and the proton exchange membrane 1 on the surface of the carbon paper 4 by ink-jet printing. Selecting a catalyst Hispec9100(JM), and selecting a resin Nafion D520, a resin Aquivion D98-25BS, a microporous carbon material and expandable Gore PTFE.

Preparing catalyst slurry:

dispersing resin A (Nafion D520 ionomer solution) in a mixed solvent by magnetic stirring, wherein the mixed solvent consists of isopropanol and deionized water, and placing the mixture in a container which can be vacuumized and stirring for 24 hours to prepare a dispersed solution; wherein, the resin Nafion D520 ionomer solution comprises the following components in percentage by mass: isopropyl alcohol: deionized water 5: 35: 40, mixing the catalyst A with the dispersion solution, starting a constant-temperature water bath of an ultrasonic dispersion machine, setting the temperature to be 17 ℃, the ultrasonic frequency to be 25kHz and the power to be 700W, and performing ultrasonic dispersion for 30min to obtain catalyst slurry A; wherein, the catalyst TEC10E50E (TKK) comprises the following components in percentage by mass: resin Nafion D520 monomer solution: isopropyl alcohol: deionized water 8: 5: 35: 40.

preparing a proton exchange membrane 1 slurry:

dispersing resin Aquivion D98-25BS ionomer solution in a mixed solvent through magnetic stirring, wherein the mixed solvent consists of ethanol and deionized water, and placing the mixture in a container which can be vacuumized and stirring for 48 hours to prepare a dispersed solution; wherein, the resin Aquivion D98-25BS ionomer solution comprises the following components in percentage by mass: ethanol: deionized water 10: 10: 10.

preparing a microporous layer 3 slurry:

dispersing a microporous carbon material (XC-72) in a mixed solvent by magnetic stirring, wherein the mixed solvent consists of isopropanol and deionized water, obtaining slurry by mechanical stirring and ultrasonic dispersion treatment, and placing the slurry in a container which can be vacuumized and stirring for 48 hours to prepare a dispersion solution; wherein XC-72 carbon powder, PTFE, Nafion and isopropanol are counted according to the mass ratio of 1: 0.4: 0.5: 20.

The catalyst slurry, proton exchange membrane 1 slurry and microporous layer 3 slurry were placed in three slurry storage boxes, respectively, as shown in fig. 2, and a spray coating procedure was set up. In the specific process, as shown in fig. 13, the microporous layer 3 is sprayed on the surface of the carbon paper 4, the hydrophobic microporous layer 3 is formed on the surface of the carbon paper, and a proper microporous structure can be formed in the drying process, so that sufficient support and gas transmission are provided in the power generation process of the catalytic layer 2; and then, the catalyst layer 2 can be directly sprayed, and the short spraying interval can effectively increase the fluidity of the catalyst layer 2 when contacting the microporous layer 3, so that the gaps on the surface of the microporous layer 3 are filled better, and the water drainage capability in the operation process is ensured. And then, carrying out ink-jet printing on the proton exchange membrane 1 on the surface of the PTFE base membrane 5, after spraying a certain thickness, adding an e-PTFE reinforced layer on the surface, and spraying the proton exchange membrane 1 with a certain thickness on the surface, thereby effectively increasing the durability of the self-made proton exchange membrane 1.

Laminating the anode GDE (comprising the anode catalyst layer 2, the microporous layer 3 and the gas diffusion layer 4) with the PTFE base membrane 5 and the proton exchange membrane 1, then taking off the PTFE base membrane 5, and laminating with the cathode GDE to finally obtain the membrane electrode product.

Comparative example

Preparing catalyst slurry:

dispersing resin A (Nafion D520 ionomer solution) in a mixed solvent by magnetic stirring, wherein the mixed solvent consists of isopropanol and deionized water, and placing the mixture in a container which can be vacuumized and stirring for 12 hours to prepare a dispersed solution; wherein, the resin Nafion D520 ionomer solution comprises the following components in percentage by mass: isopropyl alcohol: deionized water 5: 35: 60, mixing the catalyst A with the dispersion solution, and performing ultrasonic dispersion for 30min to prepare catalyst slurry A; wherein, the catalyst TEC10E50E (TKK) comprises the following components in percentage by mass: resin Nafion D520 monomer solution: isopropyl alcohol: deionized water 8: 5: 35: 60.

the slurry is sprayed conventionally to form CCM, and commercial carbon paper 28BC (SGL) is used, and the final membrane electrode product is obtained after hot pressing.

As shown in fig. 14, which is a comparison graph of the performance of the membrane electrode prepared in example 1 of the present invention and the performance of the membrane electrode prepared in the comparative example, it can be seen that the membrane electrode sample prepared by applying the method of the present invention can maintain a higher planned voltage in the remaining section of the polarization curve, except that the voltage of the voltage portion of the open circuit is only equivalent to the performance of the membrane electrode prepared by the conventional method, which indicates that the membrane electrode prepared by the method has more excellent performance.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. A preparation method of a multi-layer membrane electrode with a complex structure based on ink-jet printing is characterized by comprising the following steps: respectively preparing sizing agents of layers to be printed, and performing pretreatment; respectively storing the pretreated slurry in slurry storage boxes; during ink-jet printing, the sizing agents stored in the sizing agent storage box are respectively printed on the printing base material in sequence through a plurality of nozzles to form a multilayer structure, and the multilayer structure is bonded to form the membrane electrode.

2. The method for preparing a membrane electrode based on ink-jet printing according to claim 1, wherein the layer to be printed is one or more of a proton exchange membrane, a catalytic layer, a microporous layer, a reinforcing layer and an adhesive layer.

3. The method for preparing a membrane electrode based on ink-jet printing according to claim 2, wherein the layer to be printed is of a planar structure or a three-dimensional structure.

4. The method for preparing a membrane electrode based on ink-jet printing according to claim 3, wherein the structure of the layer to be printed is controlled by adjusting the ink-jet amount, the ink-jet speed and the head travel speed.

5. The method for preparing a membrane electrode based on ink-jet printing according to claim 2, wherein the catalytic layer is one or more layers.

6. The method for preparing a membrane electrode based on ink-jet printing according to claim 2, wherein the reinforcing layer is arranged on the surface of the catalytic layer or in the proton exchange membrane; the bonding layer is arranged between the catalytic layer and the microporous layer.

7. The method for preparing a membrane electrode based on ink-jet printing according to claim 1, wherein the pretreatment is one or more of vacuum defoaming, ultrasonic cavitation, low-temperature stabilization and shear stabilization.

8. The method for preparing a membrane electrode based on ink-jet printing according to claim 1, wherein the printing substrate is one or more of a PTFE base membrane, a microporous layer, a proton exchange membrane, a catalytic layer and a carbon paper.

9. The method of claim 1, wherein the bonding is by heat pressing or lamination.

10. The method for preparing a membrane electrode based on ink-jet printing according to claim 9, wherein the hot pressing is performed at 80-180 ℃ and 0-2.5 MPa; the lamination is carried out at normal temperature and under 0-2.5 MPa.