A method for preparing a fuel cell electrode catalyst layer and a membrane electrode comprising the same.

Abstract

This invention discloses a method for preparing a fuel cell electrode catalyst layer and a membrane electrode assembly containing the catalyst, belonging to the field of fuel cell technology. The preparation method first involves mixing catalyst and resin particles to form a catalyst layer powder. After charging, the powder is transported and adhered to the membrane surface under the action of an electric field to form a catalyst layer. Then, the catalyst layer is cured by hot pressing. This invention also relates to an apparatus for implementing the above-described method for preparing the electrode catalyst layer. This method for preparing the fuel cell electrode catalyst layer does not use any solvent, avoiding problems such as membrane swelling, environmental pollution, solvent waste, and additional energy consumption caused by the use of solvents compared to traditional wet methods for preparing fuel cell electrode catalyst layers.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuel cells, and particularly relates to a preparation method of a fuel cell electrode catalyst layer and a membrane electrode comprising the same. BACKGROUND

[0002] The membrane electrode is the core component of the fuel cell, and its structure is composed of a proton exchange membrane, a catalyst layer and a gas diffusion layer. The proton exchange membrane is used to transport protons participating in the electrochemical reaction, and the catalyst layer is the place where the electrochemical reaction occurs. The catalyst / proton exchange membrane assembly combined by the two is the core component of the membrane electrode. The traditional methods for preparing the catalyst layer of the membrane electrode mainly include the doctor blade coating method, the transfer printing method and the spray coating method. In the doctor blade coating method, a slurry is prepared by mixing a catalyst and a resin solution, and then the slurry is directly coated on the surface of the proton exchange membrane, and then dried to form the catalyst layer. In the transfer printing method, a slurry is prepared by mixing a catalyst and a resin solution, and then the slurry is coated on a transfer substrate to form a catalyst layer, and finally the catalyst layer on the transfer substrate is transferred to the proton exchange membrane by hot pressing. In the spray coating method, a slurry is prepared by mixing a catalyst and a resin solution, and then the slurry is sprayed in the form of droplets on the surface of the proton exchange membrane by a spray gun, and finally dried to form the catalyst layer. As can be seen, the traditional methods for preparing the catalyst layer of the membrane electrode all use a solvent to disperse the catalyst particles and the resin components, and therefore the swelling of the membrane is prone to occur during the preparation process. In addition, the use of the solvent also causes environmental pollution, and the solvent evaporation process introduces additional energy consumption, thereby increasing the preparation cost of the catalyst layer. SUMMARY

[0003] In order to solve the problems existing in the prior art, the present application provides a method for preparing a fuel cell electrode catalyst layer and a membrane electrode comprising the same. The method of the present application discards the use of a solvent, improves the swelling problem of the membrane caused by the use of the solvent to disperse the catalyst particles and the resin components, reduces environmental pollution, solvent waste and additional energy consumption, and reduces the cost.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0005] The present application provides a method for preparing a fuel cell electrode catalyst layer, comprising the following steps:

[0006] (1) placing the catalyst layer powder on the conductive substrate A;

[0007] (2) laying and fixing the membrane on the conductive substrate B, and placing the conductive substrate A opposite to the conductive substrate B, so that the catalyst layer powder corresponds to the membrane and does not contact the membrane;

[0008] (3) heating the membrane and keeping the temperature constant, and applying a voltage to the conductive substrate A and the conductive substrate B, wherein the conductive substrate A is negative and the conductive substrate B is positive, so that the catalyst layer powder is attached to one side surface of the membrane to form an uncured catalyst layer.

[0009] (4) removing the film with uncured catalytic layer on one side and heat-pressing to cure the catalytic layer;

[0010] (5) repeating the above steps (2) to (4) to form a cured catalytic layer on the other side of the film in the same way.

[0011] The uniformity of the catalytic layer of the electrode is one of the key factors affecting its performance, and the uniform distribution of the catalytic layer powder delivered to the surface of the film in step (3) of the preparation method is conducive to the formation of a uniform catalytic layer in the subsequent steps;

[0012] In step (3) of the preparation method, the charged catalytic layer powder particles will be electro-levitated upward under the action of the electric field, but the delivery of the powder is not simply completed by electro-levitation once: part of the powder particles that are electro-levitated or adsorbed on the film will fall back to the conductive base A under the action of gravity, and then be re-electro-levitated after being charged again. The movement of the powder particles will have a horizontal velocity component under the action of charge repulsion, so there is a horizontal redistribution of the catalytic layer powder particles during the application of high voltage.

[0013] Based on the horizontal redistribution behavior of the catalytic layer powder particles described above, in step (1) of the preparation method, the powder does not need to be placed completely flat on the conductive base A, which increases the feasibility of actual operation.

[0014] Further, the catalytic layer powder is a mixture of catalyst particles and resin particles;

[0015] The catalyst is selected from one of Pt / C or platinum black;

[0016] The particle size of the catalyst particles is 1-20 nm;

[0017] The resin is selected from one of Nafion-H, PVDF or PTFE;

[0018] The particle size of the resin particles is 0.1-10 μm;

[0019] The mass ratio of the catalyst to the resin in the catalytic layer powder is 10:1-1:10;

[0020] Preferably, the mass ratio of the catalyst to the resin in the catalytic layer powder is 2:1-1:5.

[0021] Further, the film is selected from one of Nafion-H film or PBI film.

[0022] Due to the preparation process, the particle size of the catalyst and resin particles is not a certain value, but has a certain particle size distribution: for catalyst particles, the upper limit of the distribution range is less than 20 nm and the lower limit is higher than 1 nm; for resin particles, the upper limit of the distribution range is less than 10 μm and the lower limit is higher than 0.1 μm;

[0023] The powder for preparing the catalytic layer is prepared by fully mixing catalyst and resin particles, and during the mixing process, due to the electrostatic effect, a coating structure of inner layer resin and outer layer catalyst is formed, so that the catalyst particles can be as exposed as possible while being bonded by the resin to realize its catalytic function;

[0024] Based on the preparation method, the proportion of catalyst and resin is required: when the amount of catalyst is too much, the excess catalyst will easily flow out because it cannot be bonded by the resin; when the amount of catalyst is too little, it will cause waste of resin.

[0025] Further, the distance between the conductive substrate A and the conductive substrate B is 10-30 cm;

[0026] In order to promote the redistribution of the powder particles in the horizontal direction during the conveying process in step (3), the distance between the conductive substrate A and the conductive substrate B cannot be too small, otherwise the single flying time of the particles will be too short, which will make the redistribution effect worse, resulting in uneven distribution of the powder particles adsorbed on the film; on the other hand, if the distance between the conductive substrate A and the conductive substrate B is too large, the single flying time of the powder particles will be too long, which will cause too much powder to fall back and the powder adsorbed on the inner wall of the insulating shell will also increase, both of which will reduce the conveying efficiency of the powder particles.

[0027] Further, the temperature for heating the film is 60-120℃;

[0028] Preferably, the temperature for heating the film is 80-100℃.

[0029] In step (3) of the preparation method, heating the film can increase its adhesion, prevent the un-solidified catalytic layer powder particles from falling off from the film, and improve the stability of the powder particles attached to the film, which is beneficial to the actual operation; however, too high heating temperature will cause the film to deform or even decompose, resulting in a decrease in the performance of the final film electrode.

[0030] Further, the voltage applied to the conductive substrate A and the conductive substrate B is 10-100 kV;

[0031] Preferably, the voltage applied to the conductive substrate A and the conductive substrate B is 20-50 kV.

[0032] Further, the duration of the voltage applied to the conductive substrate A and the conductive substrate B is 10-120 s;

[0033] Preferably, the duration of applying voltage to the conductive substrate A and the conductive substrate B is 30-60s.

[0034] In step (3) of the preparation method, the process of transporting the powder to the film surface by high-voltage electric field is one of the keys of the whole preparation method, and therefore the parameters of the high-voltage electric field have certain requirements:

[0035] 1) The voltage affects the flying and adhesion of the powder: too low voltage will result in insufficient flying height of the powder and weakened adhesion on the film surface, and the powder is easy to fall off; while too high voltage will result in uneven distribution of the powder particles on the film surface due to the too fast transport rate, and too high voltage may also result in breakdown of the film and appearance of bad points;

[0036] 2) The application time of high voltage mainly affects the transport amount of the powder, i.e. under the condition of suitable output voltage, the application time of high voltage controls the loading amount of the powder (or catalyst) on the film.

[0037] Further, the temperature of the hot pressing is 80-200℃;

[0038] Preferably, the temperature of the hot pressing is 100-120℃.

[0039] Further, the pressure of the hot pressing is 0.1-5.0MPa;

[0040] Preferably, the pressure of the hot pressing is 0.5-1.0MPa.

[0041] Further, the time of the hot pressing is 1-60min;

[0042] Preferably, the time of the hot pressing is 5-20min.

[0043] Compared with the traditional wet method for preparing the membrane electrode catalyst layer, one of the great advantages of the preparation method of the application is that the catalyst layer can retain the macroporous structure of the powder particles to a great extent, which is beneficial to the transport of the reactants in the actual battery operation, and therefore the hot pressing process in step (4) of the preparation method is another key point of the whole preparation method, and the parameters of the hot pressing process also have certain requirements:

[0044] 1) The resin component in the powder will soften when heated, and then play a role of adhesion, if the heating temperature is too low, the adhesion will be poor, resulting in easy peeling of the catalyst particles, while too high heating temperature will result in deformation or even decomposition of the film, leading to the decline of the performance of the final membrane electrode;

[0045] 2) The application of pressure while heating helps to heat the resin particles in the powder sufficiently, improving the bonding effect, but too much pressure will destroy the pore structure between the powder particles, resulting in a decline in the performance of the final membrane electrode;

[0046] 3) The duration of the hot-pressing process should be long enough to heat and bond the powder particles and the membrane firmly.

[0047] Further, the device for preparing the fuel cell electrode catalyst layer by the preparation method comprises a conveying table, a temperature controller, a vacuum pump and a high-voltage generator, and the conveying table is a hollow sealing structure composed of a conductive base A, a hollow insulating shell and a conductive base B from bottom to top.

[0048] The temperature controller is connected with the conductive base B, the vacuum pump is connected with the conductive base B, the negative electrode of the high-voltage generator is connected with the conductive base A, and the positive electrode of the high-voltage generator is connected with the conductive base B.

[0049] The conductive base B is provided with a heating wire interface, a thermocouple interface and an air outlet, the heating wire interface is connected with the heating interface of the temperature controller, the thermocouple interface is connected with the temperature measuring interface of the temperature controller, and the air outlet is connected with the air inlet of the vacuum pump.

[0050] Further, the conductive base A and the conductive base B should have good electrical conductivity, and the materials thereof include stainless steel.

[0051] In the device, the conductive base A of the conveying table needs to have a flat surface, and the flat surface is beneficial to the contact between the powder and the conductive base A, so that the charging of the powder is more uniform.

[0052] In the device, the conductive base B of the conveying table also needs to have a flat surface, and the flat surface is beneficial to the close contact of the membrane and the better heating effect, and is also beneficial to the uniform distribution of the electric field on the surface of the membrane, preventing the powder from concentrating in a certain position during the conveying process.

[0053] In the device, the conductive base B of the conveying table is provided with small holes with a pore size of 1 mm on the surface thereof, which are connected with the air outlet and are used for adsorbing and fixing the membrane by vacuum suction, and the surface is provided with heating wires and thermocouples for heating the surface.

[0054] The material of the insulating shell in the conveying table includes one of polymethyl methacrylate (PMMA) or polytetrafluoroethylene (PTFE).

[0055] In order to ensure normal operation of the whole device, the insulating shell in the conveying table needs to ensure good insulation. Since a small amount of powder particles will be adsorbed on the inner wall of the shell during the flying process, when the adsorption amount accumulates to a certain extent, a conductive loop will be formed on the inner wall of the shell, which will cause the insulation of the shell to deteriorate, and a strong electric field cannot be formed in the cavity between the conductive base A and the conductive base B, so that the device cannot work normally. At this time, the inner wall of the insulating shell needs to be cleaned.

[0056] Further, the method for preparing a fuel cell membrane electrode catalyst layer by using the device comprises the following steps:

[0057] (1) Place the catalyst layer powder on the conductive base A, place and fix the insulating shell on the conductive base A, and make the catalyst layer powder located at the inner bottom of the insulating shell;

[0058] (2) Turn on the vacuum pump, flatten and attach the membrane on the conductive base B through the air pressure difference, and then invert it on the top of the insulating shell, at this time, the side of the conductive base B with the membrane is downward and opposite to the catalyst layer powder;

[0059] (3) Turn on the temperature controller to heat and keep the temperature of the membrane constant, then turn on the high-voltage generator to charge the catalyst layer powder on the conductive base A, and transport it to the surface of the membrane through the high-voltage electric field, and turn off the high-voltage generator, at this time, the powder is adsorbed on one side of the membrane to form an uncured catalyst layer due to electrostatic action;

[0060] (4) Turn off the temperature controller and the vacuum pump, take down the membrane with one side of the catalyst layer and perform hot pressing treatment to make the catalyst layer solidify;

[0061] (5) Repeat the above steps (2) to (4) to make the other side of the membrane also form a solidified catalyst layer.

[0062] The application also provides a fuel cell electrode catalyst layer prepared by the above preparation method, wherein the fuel cell electrode catalyst layer is formed by mutual adhesion and accumulation of resin particles coated with catalyst particles on the surface, and has an interlaced pore structure between the resin particles.

[0063] The application also provides a fuel cell electrode catalyst layer prepared by the above preparation method, wherein the fuel cell electrode catalyst layer is formed by mutual adhesion and accumulation of resin particles coated with catalyst particles on the surface, and has an interlaced pore structure between the resin particles.

[0064] The application also provides a fuel cell membrane electrode comprising the above electrode catalyst layer.

[0065] Compared with the prior art, the preparation method of the fuel cell electrode catalyst layer has the following advantages:

[0066] (1) Compared with the wet method for preparing the membrane electrode catalyst layer, the electrode catalyst layer preparation method does not use any organic or inorganic solvent, avoiding the problem of membrane swelling;

[0067] (2) The electrode catalyst layer preparation method does not use a solvent to disperse the resin material and the catalyst, avoiding the additional energy consumption caused by the solvent evaporation step, thus reducing the preparation cost;

[0068] (3) In the process of preparing the membrane electrode catalyst layer by the wet method, the solvent component is eventually volatilized, so the electrode catalyst layer preparation method is more green and environmentally friendly;

[0069] (4) The powder particles containing resin and catalyst are directly transmitted to the membrane surface by a high-voltage electric field, so the electrode catalyst layer can retain the macroporous structure of the powder particles to a large extent, which is beneficial to the transmission of the reactant materials during actual cell operation;

[0070] (5) The catalyst in the electrode catalyst layer is coated on the outer layer of the resin, which is beneficial to its contact with the reactant materials, thus improving the utilization rate of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0071] Figure 1 is a structural schematic diagram of a transmission table (1) in the device used in the preparation method of the electrode catalyst layer.

[0072] Figure 2 is a schematic diagram of the device used in the preparation method of the electrode catalyst layer. In the figure: 1, transmission table; 11, conductive substrate A; 12, insulating shell; 13, conductive substrate B; 14, powder; 15, membrane; 2, temperature controller; 3, vacuum pump; 4, high-voltage generator.

[0073] Figure 3 is a SEM image of the catalyst / membrane assembly CCM-1 (side view) containing the fuel cell electrode catalyst layer.

[0074] Figure 4 is the performance test result (polarization curve) of a single fuel cell installed with the catalyst / membrane assembly CCM-1.

[0075] Figure 5 is the stability test result of a single fuel cell installed with the catalyst / membrane assembly CCM-1. DETAILED DESCRIPTION

[0076] In order to further illustrate the present application, the following examples are given according to the experimental results combined with the drawings, but do not limit the scope of the invention defined by the claims.

[0077] Example 1

[0078] The device for preparing the electrode catalytic layer is shown in Figures 1-2 The device for preparing the electrode catalytic layer is shown in

[0079] The transfer platform 1 is composed of a conductive substrate A 11, an insulating shell 12 and a conductive substrate B 13 from bottom to top. The insulating shell 12 is a hollow shell structure without top and bottom, and the conductive substrate A 11 and the conductive substrate B 13 are respectively located at the bottom and top of the insulating shell 12, so as to form a closed space inside the insulating shell 12. The conductive substrate A 11 inside the insulating shell 12 is placed with powder 14 for preparing the catalytic layer, and a film 15 is arranged between the conductive substrate B 13 and the insulating shell 12.

[0080] The conductive substrate B 13 is connected with a temperature controller 2 and a vacuum pump 3, the conductive substrate B 13 is connected with the ground end (positive electrode) of a high-voltage generator 4, and the conductive substrate A 11 is connected with the high-voltage end (negative electrode) of the high-voltage generator 4.

[0081] The conductive substrate B 13 is a vacuum heating platform, which is provided with a heating wire interface, a thermocouple interface and an air outlet. The heating wire interface is connected with the heating interface of the temperature controller 2, the thermocouple interface is connected with the temperature measuring interface of the temperature controller 2, and the air outlet is connected with the air inlet of the vacuum pump 3.

[0082] In the initial stage of preparing the electrode catalytic layer, the catalyst and resin particles are first mixed to form powder 14, which is placed on the conductive substrate A 11 of the transfer platform 1. Then, the insulating shell 12 is placed and fixed on the conductive substrate A 11, and at this time, the powder 14 is located at the inner bottom of the insulating shell 12. Then, the vacuum pump 3 is turned on, the film 15 is laid on the conductive substrate B 13 by air pressure difference, and then it is inverted on the top of the insulating shell 12, and at this time, the conductive substrate B 13 with the film 15 is downward, i.e. towards the powder 14.

[0083] Example 2

[0084] This embodiment illustrates the preparation of the electrode catalytic layer of the fuel cell by using the preparation method.

[0085] 1) First, according to Example 1 and combined with Figures 1-2 The device for preparing the electrode catalytic layer is installed, then the Pt / C catalyst (Pt content is 40wt.%) is mixed with Nafion-H resin (particle size distribution is 0.7-5.0μm) according to the mass ratio of 1:1 to form powder, which is placed on the conductive substrate A, and then the insulating shell with a height of 15cm is fixed on the periphery of the catalyst on the substrate;

[0086] 2) Turn on the vacuum pump, lay the Nafion-H membrane flat on the vacuum heating stage and invert it on the top of the insulating shell;

[0087] 3) Turn on the temperature controller and set the temperature to 90℃. After the temperature stabilizes, turn on the high voltage generator, set the output voltage to 20kV and the output current to 20μA, and charge and transport the powder on the substrate. The output process lasts for 30 seconds, and then turn off the high voltage generator.

[0088] 4) Turn off the temperature controller and vacuum pump, remove the Nafion-H membrane with adsorbed powder particles, place it on the hot press table for hot pressing treatment, the hot pressing temperature is 120℃, the hot pressing pressure is 1.0MPa, and the hot pressing time is 10min.

[0089] 5) Turn the vacuum pump back on, lay the Nafion-H membrane with the catalyst layer facing inward on the vacuum heating stage and invert it on the top of the insulating shell;

[0090] 6) Repeat steps 3) and 4) above to form a catalytic layer on the other side of the Nafion-H membrane, and obtain the prepared catalyst / membrane module, denoted as CCM-1.

[0091] The morphology of the catalyst / membrane module CCM-1 was characterized by SEM, and the results are attached. Figure 3 As shown, the skeletal structure of its electrode catalyst layer is formed by the bonding of resin particles together. The particles stack up to form an interlaced pore structure. Furthermore, the relatively small catalyst particles are attached to the surface of the relatively large resin particles, so that the catalyst particles can be exposed as much as possible while being bonded by the resin in order to realize their catalytic function.

[0092] Example 3

[0093] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the ratio of catalyst and resin using the preparation method described in Example 2, as a comparison with Example 2.

[0094] Except that the mass ratio of catalyst to Nafion resin in step 1) is changed from 1:1 to 5:1, the catalyst / membrane module, denoted as CCM-2, was prepared using the same preparation method as in Example 2.

[0095] Example 4

[0096] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the ratio of catalyst and resin using the preparation method described in Example 2, as a comparison with Example 2.

[0097] Except that the mass ratio of catalyst to Nafion resin in step 1) is changed from 1:1 to 2:1, the catalyst / membrane module, denoted as CCM-3, was prepared by the same preparation method as in Example 2.

[0098] Example 5

[0099] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the ratio of catalyst and resin using the preparation method described in Example 2, as a comparison with Example 2.

[0100] Except that the mass ratio of catalyst to Nafion resin in step 1) is changed from 1:1 to 1:2, the catalyst / membrane module, denoted as CCM-4, was prepared using the same preparation method as in Example 2.

[0101] Example 6

[0102] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the ratio of catalyst and resin using the preparation method described in Example 2, as a comparison with Example 2.

[0103] Except that in step 1), the mass ratio of catalyst to Nafion resin was changed from 1:1 to 1:5, the catalyst / membrane module was prepared using the same preparation method as in Example 2, and was designated as CCM-5.

[0104] Example 7

[0105] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the heating temperature during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0106] Except for step 3), where the temperature controller setting temperature is changed from 90°C to 100°C, the catalyst / membrane module, denoted as CCM-6, was prepared using the same preparation method as in Example 2.

[0107] Example 8

[0108] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the heating temperature during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0109] Except for step 3), where the temperature controller setting temperature is changed from 90°C to 80°C, the catalyst / membrane module, denoted as CCM-7, was prepared using the same preparation method as in Example 2.

[0110] Example 9

[0111] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the heating temperature during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0112] Except for step 3), where the temperature controller setting temperature is changed from 90°C to 70°C, the catalyst / membrane module, denoted as CCM-8, was prepared using the same preparation method as in Example 2.

[0113] Example 10

[0114] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the heating temperature during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0115] Except for step 3), where the temperature controller setting temperature is changed from 90°C to 60°C, the catalyst / membrane module, denoted as CCM-9, was prepared using the same preparation method as in Example 2.

[0116] Example 11

[0117] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the output voltage of the high-voltage generator during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0118] Except that the output voltage of the high voltage generator in step 3) is replaced by 50kV instead of 20kV, the catalyst / membrane module, denoted as CCM-10, is prepared using the same preparation method as in Example 2.

[0119] Example 12

[0120] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the output voltage of the high-voltage generator during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0121] Except that the output voltage of the high voltage generator in step 3) is replaced by 80kV instead of 20kV, the catalyst / membrane module, denoted as CCM-11, is prepared using the same preparation method as in Example 2.

[0122] Example 13

[0123] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the output time of the high-voltage generator during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0124] Except for step 3), where the output time of the high-pressure generator is replaced by 40s instead of 30s, the catalyst / membrane module, denoted as CCM-12, was prepared using the same preparation method as in Example 2.

[0125] Example 14

[0126] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the output time of the high-voltage generator during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0127] Except for step 3), where the output time of the high-pressure generator is replaced by 50s instead of 30s, the catalyst / membrane module, denoted as CCM-13, was prepared using the same preparation method as in Example 2.

[0128] Example 15

[0129] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer by changing the output time of the high-voltage generator during the delivery process using the preparation method described in Example 2, as a comparison with Example 2.

[0130] Except that the output time of the high-pressure generator in step 3) is replaced by 60s instead of 30s, the catalyst / membrane module, denoted as CCM-14, was prepared using the same preparation method as in Example 2.

[0131] Example 16

[0132] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, but with a change in the hot-pressing temperature, as a comparison with Example 2.

[0133] Except for step 4), where the hot pressing temperature is changed from 120°C to 140°C, the catalyst / membrane module, denoted as CCM-15, was prepared using the same preparation method as in Example 2.

[0134] Example 17

[0135] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, but with a change in the hot-pressing temperature, as a comparison with Example 2.

[0136] Except for step 4), where the hot pressing temperature is changed from 120°C to 100°C, the catalyst / membrane module, denoted as CCM-16, was prepared using the same preparation method as in Example 2.

[0137] Example 18

[0138] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, but with a change in the hot-pressing temperature, as a comparison with Example 2.

[0139] Except for step 4), where the hot pressing temperature is changed from 120°C to 80°C, the catalyst / membrane module, denoted as CCM-17, was prepared using the same preparation method as in Example 2.

[0140] Example 19

[0141] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, but with a change in hot-pressing pressure, as a comparison with Example 2.

[0142] Except that the hot pressing pressure in step 4) is changed from 1.0 MPa to 2.0 MPa, the catalyst / membrane module, denoted as CCM-18, was prepared using the same preparation method as in Example 2.

[0143] Example 20

[0144] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, but with a change in hot-pressing pressure, as a comparison with Example 2.

[0145] Except that the hot pressing pressure in step 4) is changed from 1.0 MPa to 0.5 MPa, the catalyst / membrane module, denoted as CCM-19, was prepared using the same preparation method as in Example 2.

[0146] Example 21

[0147] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, but with a change in hot-pressing pressure, as a comparison with Example 2.

[0148] Except that the hot pressing pressure in step 4) is changed from 1.0 MPa to 0.1 MPa, the catalyst / membrane module, denoted as CCM-20, was prepared using the same preparation method as in Example 2.

[0149] Example 22

[0150] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, with a change in the hot-pressing time, as a comparison with Example 2.

[0151] Except for step 4), where the hot pressing time is changed from 10 min to 20 min, the catalyst / membrane module, denoted as CCM-21, was prepared using the same preparation method as in Example 2.

[0152] Example 23

[0153] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, with a change in the hot-pressing time, as a comparison with Example 2.

[0154] Except for step 4), where the hot pressing time is changed from 10 min to 5 min, the catalyst / membrane module, denoted as CCM-22, was prepared using the same preparation method as in Example 2.

[0155] Example 24

[0156] This embodiment illustrates the preparation of a fuel cell electrode catalyst layer using the preparation method described in Example 2, with a change in the hot-pressing time, as a comparison with Example 2.

[0157] Except for step 4), where the hot pressing time is changed from 10 min to 1 min, the catalyst / membrane module, denoted as CCM-23, was prepared using the same preparation method as in Example 2.

[0158] Example 25

[0159] This embodiment illustrates the performance testing of the fuel cell catalyst / membrane module prepared by the described method.

[0160] The catalyst / membrane modules CCM-1 to CCM-23 prepared in Examples 2-24 were cut and hot-pressed together with the diffusion layer and frame to form membrane electrode assemblies, which were then installed on a single fuel cell (the effective area of ​​the CCM is 2.0 × 2.5 cm). 2 Then, the single-cell battery was installed on a fuel cell test bench for performance testing. The test conditions were as follows: air was introduced into the positive electrode side at a pressure of 0.1 MPa and a flow rate of 800 mL / min; hydrogen was introduced into the negative electrode side at a pressure of 0.1 MPa and a flow rate of 200 mL / min; the battery was kept at a constant temperature of 80°C; and the temperature of the positive and negative electrode humidification tanks was 80°C (100% humidification). At the start of the test, the above parameters were set and stabilized before the electronic load was turned on, with the output current density set to 1000 mA / cm². 2 The membrane electrode was activated, and the activation process lasted for 6 hours. After the activation process was completed, the polarization curve was measured. Taking the catalyst / membrane module CCM-1 as an example, its polarization curve is shown in the attached figure. Figure 4 As shown. Record the open-circuit voltage (corresponding to a current density of 0) and 500 mA / cm² in each polarization curve. 2 Corresponding voltage and 1000mA / cm 2 The corresponding voltages and results are shown in the table below:

[0161]

[0162]

[0163] Example 26

[0164] This embodiment illustrates the stability test of a single-cell fuel cell installed using the catalyst / membrane module CCM-1.

[0165] The catalyst / membrane module CCM-1 prepared in Example 2 was cut and then hot-pressed together with the diffusion layer and frame to form a membrane electrode assembly, which was then installed on a single fuel cell (the effective area of ​​the CCM is 2.0 × 2.5 cm). 2Then, the single-cell battery was installed on a fuel cell test bench for performance testing. The test conditions were as follows: air was introduced into the positive electrode side at a pressure of 0.1 MPa and a flow rate of 800 mL / min; hydrogen was introduced into the negative electrode side at a pressure of 0.1 MPa and a flow rate of 200 mL / min; the battery was kept at a constant temperature of 80°C; and the temperature of the positive and negative electrode humidification tanks was 80°C (100% humidification). At the start of the test, the above parameters were set and stabilized before the electronic load was turned on, with the output current density set to 1000 mA / cm². 2 The membrane electrode was activated, and the activation process lasted for 6 hours. After the activation process was completed, the output current density was maintained at 1000 mA / cm². 2 The battery output voltage was recorded every 2 hours for 120 hours. The results are shown in the attached figure. Figure 5 As shown, the membrane electrode with the electrode catalytic layer prepared according to the method described in this invention has good stability.

Claims

1. A method of making a catalytic layer of a fuel cell electrode, characterized by: The preparation method comprises the following steps: (1) placing the catalytic layer powder on the conductive substrate A; (2) laying and fixing the membrane on the conductive substrate B, placing the conductive substrate A opposite to the conductive substrate B, and making the catalytic layer powder correspond to the membrane without contact; (3) heating and keeping constant temperature of the membrane, applying voltage to the conductive substrate A and the conductive substrate B, wherein the conductive substrate A is negative and the conductive substrate B is positive, and making the catalytic layer powder adhere to one side surface of the membrane to form the uncured catalytic layer; (4) taking off the membrane with the uncured catalytic layer and performing hot pressing to make the catalytic layer cured; (5) repeating the above steps (2) to (4) to form the cured catalytic layer on the other side of the membrane by the same method; The catalytic layer powder is mixed by the catalyst particles and the resin particles; The catalyst is selected from one of Pt / C or platinum black; The particle size of the catalyst particles is 1-20 nm; The particle size of the resin particles is 0.1-10 μm; The conductive substrate B is a vacuum heating platform; The distance between the conductive substrate A and the conductive substrate B is 10-30 cm; The voltage applied to the conductive substrate A and the conductive substrate B is 10-100 kV; The time of applying voltage to the conductive substrate A and the conductive substrate B is 10-120 s.

2. The preparation method according to claim 1, wherein: The resin is selected from one of Nafion-H, PVDF or PTFE; The mass ratio of the catalyst and the resin in the catalytic layer powder is 10:1-1:

10.

3. The preparation method according to claim 1, wherein: The membrane is selected from one of Nafion-H membrane or PBI membrane.

4. The preparation method according to claim 1, wherein: The heating temperature of the membrane is 60-120 ℃.

5. The preparation method according to claim 1, wherein: The hot pressing temperature is 80-200 ℃; The hot pressing pressure is 0.1-5.0 MPa; The hot pressing time is 1-60 min.

6. The preparation method according to claim 1, wherein: The device for preparing the fuel cell electrode catalytic layer by the preparation method comprises a conveying table (1), a temperature controller (2), a vacuum pump (3) and a high-voltage generator (4), and the structure of the conveying table (1) comprises a hollow sealing structure of the conductive substrate A (11), a hollow insulating shell (12) and the conductive substrate B (13) from bottom to top. The temperature controller (2) is connected with the conductive substrate B (13), the vacuum pump (3) is connected with the conductive substrate B (13), the negative electrode of the high-voltage generator (4) is connected with the conductive substrate A (11), and the positive electrode of the high-voltage generator (4) is connected with the conductive substrate B (13).

7. The preparation method according to claim 6, wherein: The material of the conductive substrate A (11) and the conductive substrate B (13) comprises stainless steel; The material of the insulating shell (12) is one of polymethyl methacrylate or polytetrafluoroethylene.

8. The method of claim 6, wherein: A method for preparing a fuel cell membrane electrode catalyst layer using the device comprises the following steps: (1) placing the catalyst layer powder on the conductive substrate A, placing and fixing the insulating shell on the conductive substrate A, and placing the catalyst layer powder on the inner bottom of the insulating shell; (2) opening the vacuum pump, placing the membrane on the conductive substrate B by air pressure difference, and then inverting the membrane on the top of the insulating shell, at this time the conductive substrate B with the membrane is downward and opposite to the catalyst layer powder; (3) opening the temperature controller, heating and keeping the temperature of the membrane, then opening the high-voltage generator, charging the catalyst layer powder on the conductive substrate A, and transporting the catalyst layer powder to the surface of the membrane by high-voltage electric field, closing the high-voltage generator, at this time the powder is adsorbed on one side of the membrane by electrostatic effect to form an uncured catalyst layer; (4) closing the temperature controller and the vacuum pump, taking the membrane with the catalyst layer on one side and performing hot pressing treatment to solidify the catalyst layer; (5) repeating the above steps (2) to (4) to form a solidified catalyst layer on the other side of the membrane.

9. The fuel cell electrode catalyst layer prepared by the preparation method of any one of claims 1-8, characterized in that: The fuel cell electrode catalyst layer is formed by mutual adhesion and accumulation of resin particles coated with catalyst particles on the surface, and has an interlaced pore structure between the resin particles.

10. A fuel cell membrane electrode, characterized in that: The fuel cell membrane electrode comprises the electrode catalyst layer of claim 9.

Images