A PEMEC five-in-one electrode and its preparation method

Abstract

The present invention provides a PEMEC five-in-one electrode and a preparation method thereof. The method includes: performing electroplating metal treatment on a titanium mesh to obtain a catalytic layer skeleton; preparing an anode catalytic layer ink and a cathode catalytic layer ink; spraying the inks onto one side of the catalytic layer skeleton respectively by ultrasonic spraying to form an anode catalytic layer and a cathode catalytic layer respectively; covering the surface of the catalytic layer with a Nafion solution to form a Nafion layer; standing for shaping to obtain a cathode electrode and an anode electrode; respectively thermocompression bonding the cathode electrode and the anode electrode to both sides of a proton exchange membrane subjected to thermocompression treatment to obtain a PEMEC five-in-one electrode. The present invention uses a titanium mesh as a skeleton to prepare a PTE electrode in a form of non-uniform loading, combines with a proton exchange membrane to obtain a five-in-one electrode, can solve the problem of noble metal waste, and the prepared electrode can be used in a PEM electrolyzer and can also be applied to reaction devices with the same structure such as a PEM fuel cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen energy, and particularly relates to a PEMEC five-in-one electrode and a preparation method thereof. Background Art

[0002] Traditional commercial membrane electrodes are usually in the form of CCM (coating the catalyst layer on the proton exchange membrane), and then combined with components such as a porous transport layer and a bipolar plate to form an electrolytic cell. In this way, the catalyst layer that is not in direct contact with the porous transport layer will be wasted due to ohmic impedance.

[0003] To solve the problem of precious metal waste, many studies have started to prepare by the PTE method. However, most studies still use titanium felt as the porous transport layer. When spraying the catalyst layer ink, leakage will occur. The ink leaking into the titanium felt will have an "island" effect, which not only causes waste of the catalyst but also affects the water and gas transport of the electrode. Therefore, preparing PTE with traditional titanium felt cannot reduce the manufacturing cost of the membrane electrode. Summary of the Invention

[0004] To solve the above technical problems, the purpose of the present invention is to provide a PEMEC five-in-one electrode and a preparation method thereof, which can avoid the waste of precious metals in the PEMEC electrode and reduce the manufacturing cost of the electrode.

[0005] To achieve the above object, the present invention first provides a preparation method of a PEMEC five-in-one electrode, which includes the following steps:

[0006] Perform electroplating metal treatment on the titanium mesh to form a plating layer and obtain a catalyst layer skeleton;

[0007] Prepare an anode catalyst layer ink and a cathode catalyst layer ink. Among them, the anode catalyst layer ink is made of a nano-scale iridium oxide catalyst, a Nafion solution, deionized water, and a solvent (preferably n-propanol). Among them, the mass ratio of the polymer material in the Nafion solution to the nano-scale iridium oxide catalyst is (0.125 - 0.5):1, and the solid content of the anode catalyst layer ink is 1% - 5%; the cathode catalyst layer ink is made of a nano-scale platinum on carbon catalyst, a Nafion solution, deionized water, and a solvent. Among them, the mass ratio of the polymer material in the Nafion solution to the carbon carrier of the nano-scale platinum on carbon catalyst is (0.35 - 1):1, and the solid content of the cathode catalyst layer ink is 1% - 2%;

[0008] Spray the anode catalyst layer ink and the cathode catalyst layer ink onto one side of the catalyst layer skeleton by ultrasonic spraying to form an anode catalyst layer and a cathode catalyst layer respectively;

[0009] Cover the Nafion solution on the surfaces of the anode catalyst layer and the cathode catalyst layer respectively to form Nafion layers, and obtain the cathode electrode and the anode electrode;

[0010] Thermocompression mold the cathode electrode and the anode electrode respectively in the way that the catalyst layer faces upward with the Nafion layer. The thermocompression temperature includes but is not limited to 110°C - 150°C, and the thermocompression pressure includes but is not limited to 4 MPa - 12 MPa, to obtain the cathode electrode and the anode electrode respectively;

[0011] Thermocompression bond the cathode electrode and the anode electrode respectively to both sides of the proton exchange membrane that has been thermally processed to obtain the PEMEC five-in-one electrode.

[0012] In the above preparation method, preferably, the mass ratio of the polymer material in the Nafion solution to the carbon carrier of the nano-scale platinum-on-carbon catalyst is (0.6 - 1):1.

[0013] In the above preparation method, the nano-scale iridium oxide catalyst is nano-scale iridium oxide particles.

[0014] In the above preparation method, the mass ratio of deionized water to the solvent in the anode catalyst layer ink can be adjusted according to actual needs, and is preferably (0.5 - 1):50; the mass ratio of deionized water to the solvent in the cathode catalyst layer ink can be adjusted according to actual needs, and is preferably (5 - 10):50.

[0015] In the above preparation method, preferably, the titanium mesh is TA1 type titanium mesh (American standard GR1 type); more preferably, the titanium mesh is plain weave or twill weave, and the aperture is 50 - 600 mesh (more preferably 200 mesh). Using plain weave or twill weave titanium mesh can bring better water-vapor transmission effect (both with a thickness of 200 μm) and uniformity.

[0016] In the above preparation method, preferably, the metal used for electroplating the titanium mesh is selected from one or a combination of two or more of metals such as platinum, gold, and iridium. Electroplating these metals can improve the electrical conductivity and reduce the contact impedance.

[0017] In the above preparation method, the thickness of the electroplated layer can be controlled according to needs in a conventional manner in the art, and is preferably 500 nm.

[0018] In the above preparation method, preferably, the anode catalyst layer ink is prepared by the following steps: mixing nano-scale iridium oxide particles and deionized water, and dispersing them through ultrasonic stirring in a water bath to obtain a dispersion; sequentially adding a Nafion solution (such as Dupont Nafion D520 solution, concentration 5%) and a solvent (preferably n-propanol) to the above dispersion, and performing ball milling to obtain a mixed solution; performing degassing treatment on the mixed solution to obtain the anode catalyst layer ink. In the present invention, deionized water and the noble metal catalyst (particles) are first ultrasonically stirred separately in a water bath, and then the Nafion solution and the solvent are added, which can avoid the ignition of the noble metal when encountering a low-boiling solvent.

[0019] In the above preparation method, preferably, the cathode catalyst layer ink is prepared by the following steps: mixing nano-scale platinum-on-carbon catalyst and deionized water, and dispersing them through ultrasonic stirring in a water bath to obtain a dispersion; sequentially adding a Nafion solution and a solvent (preferably n-propanol) to the above dispersion, and performing ball milling to obtain a mixed solution; performing degassing treatment on the mixed solution to obtain the anode catalyst layer ink.

[0020] In the above preparation method, preferably, the temperature when mixing nano-scale iridium oxide particles and deionized water is room temperature 25°C.

[0021] In the above preparation method, preferably, the particle size of the nano-scale iridium oxide particles is 2 - 20 nm.

[0022] In the above preparation method, the particle size of the platinum-on-carbon particles is mainly determined by the carbon carrier, and the carbon particle range is preferably 40 - 60 nm.

[0023] In the above preparation method, preferably, the temperature when mixing nano-scale platinum-on-carbon catalyst and deionized water is room temperature 25°C.

[0024] In the above preparation method, preferably, the time of ultrasonic stirring in the water bath is 3 - 5 minutes. Ultrasonic stirring in the water bath can fully mix water and the catalyst and isolate the catalyst from air.

[0025] In the above preparation method, preferably, the ball milling is carried out in a planetary ball milling mode, with a rotation speed of 300 - 1500 r / min and a time ranging from 0.5 - 3 hours. Generally, 300 r / min corresponds to 3 hours, and 1500 r / min corresponds to 30 min.

[0026] In the above preparation method, preferably, the degassing (defoaming) is carried out by centrifugal degassing, the centrifugal speed is 2000-2200r / min, and the time is 15-20 seconds. During the degassing process, the centrifugal speed should be controlled within the above range. If the speed is too low, the bubbles cannot be completely eliminated; if the speed is too high, the solids will sink to the bottom; both of these situations are not good for the ink.

[0027] In the above preparation method, preferably, the process of preparing the anode catalyst layer ink and the cathode catalyst layer ink respectively comprises the following steps:

[0028] The mixed liquid is dispersed by ultrasonic stirring to obtain a further dispersed mixed liquid, and then the further dispersed mixed liquid is degassed.

[0029] In the above preparation method, preferably, the dispersion frequency of the ultrasonic stirring dispersion is 5 seconds for dispersion and 3 seconds for rest.

[0030] In the above preparation method, preferably, the ultrasonic frequency of the ultrasonic stirring and dispersing is 20-40 kHz.

[0031] In the above preparation method, preferably, the ultrasonic stirring and dispersing time is 10-15 minutes.

[0032] In the above preparation method, preferably, the ultrasonic frequency of the ultrasonic spraying nozzle is 25-180 kHz, more preferably 120 kHz.

[0033] In the above preparation method, preferably, the thickness of the anode catalyst layer is 0.8-2 μm; the thickness of the cathode catalyst layer is 6-10 μm.

[0034] In the above preparation method, preferably, the thickness of the Nafion layer is 0.5-1 μm.

[0035] In the above preparation method, preferably, the proton exchange membrane subjected to hot pressing is obtained by hot pressing the proton exchange membrane under the conditions of temperature 100-120°C and pressure 8-12MPa (more preferably 110°C and 10MPa). Hot pressing the membrane can remove moisture and bubbles in the membrane, and the temperature needs to be greater than 100°C but not more than 120°C. Too high temperature and pressure will damage the membrane.

[0036] In the above preparation method, preferably, the temperature of the static molding is 130° C. and the time is 10 minutes.

[0037] In the above preparation method, preferably, the temperature of the hot pressing and compounding is 110 - 130 °C (preferably 130 °C), and the pressure is 2 - 5 MPa (preferably 4 - 5 MPa); the time of the hot pressing and compounding can be adjusted according to the actual situation, for example, the time is 5 minutes.

[0038] The present invention also provides a PEMEC five-in-one electrode, which is prepared by the above preparation method.

[0039] According to the specific embodiments of the present invention, preferably, the above PEMEC five-in-one electrode is composed of an anode catalyst layer, an anode catalyst layer skeleton, a proton exchange membrane, a cathode catalyst layer skeleton, and a cathode catalyst layer. Moreover, Nafion layers are respectively coated on the surfaces of the anode catalyst layer and the cathode catalyst layer. Among them, the anode catalyst layer and the anode catalyst layer skeleton are combined into an anode electrode, which is located on the anode side of the proton exchange membrane; the cathode catalyst layer skeleton and the cathode catalyst layer are located on the cathode side of the proton exchange membrane; the anode catalyst layer skeleton and the cathode catalyst layer skeleton are respectively composed of titanium meshes, the anode catalyst layer is composed of nanoscale iridium oxide particles and Nafion polymer ionomers, and the cathode catalyst layer is composed of nanoscale platinum-on-carbon particles and Nafion polymer ionomers.

[0040] The technical solution of the present invention can be applied to different types of catalysts and proton exchange membrane materials. By using the ultrasonic spraying method, the catalyst ink is attached to the catalyst layer skeleton to form a non-uniformly supported catalyst layer, thereby reducing the waste of the catalyst. Then, the Nafion binder is sprayed onto the catalyst layer to improve the adhesion of the catalyst layer and prevent the shedding of the catalyst layer. Finally, a five-in-one electrode is formed by integral hot pressing. This electrode has characteristics such as low impedance and high performance.

[0041] The present invention uses a titanium mesh as the skeleton and adopts a non-uniform loading form to prepare a PTE electrode, and then combines it with a proton exchange membrane to obtain a five-in-one electrode, which can solve the problem of noble metal waste in PEMEC electrodes. The prepared electrode can be used in PEM electrolyzers and can also be applied to reaction devices with the same structure such as PEM fuel cells. Description of the Drawings

[0042] Figure 1 Scanning electron micrograph of the PTE electrode prepared in Example 1.

[0043] Figure 2 Scanning electron micrograph of the PTE electrode prepared in Comparative Example 1.

[0044] Figure 3 Scanning electron micrograph of the electrodes prepared under different pressures.

[0045] Figure 4Schematic diagram of a uniformly supported CCM-form membrane electrode and a PTE-form electrode prepared by the present invention.

[0046] Figure 5 Performance comparison results between the PTE electrode prepared in Example 2 and a traditional CCM electrode. Detailed implementation manners

[0047] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solution of the present invention will be described in detail below, but it should not be construed as a limitation on the implementable scope of the present invention.

[0048] Example 1

[0049] This example provides a PEMEC five-in-one electrode, which is prepared by the following method:

[0050] 1. Pretreatment of the catalytic layer skeleton: Select a TA1-type titanium mesh with a thickness of 200 μm and a mesh size of 200 as the anode catalytic layer skeleton and the cathode catalytic layer skeleton, and perform electroplating of platinum metal, with an electroplating thickness of 500 nm;

[0051] 2. Pretreatment of the proton exchange membrane: Perform hot pressing on a proton exchange membrane of the FUMA-FS-990-PK model, with a hot pressing temperature of 110 °C, a pressure of 10 MPa, and a hot pressing time of 3 minutes;

[0052] 3. Preparation of the anode catalytic layer ink: ① Mix iridium oxide particles with a particle size of 2 - 20 nm and deionized water at room temperature of 25 °C, and disperse them for 3 minutes by ultrasonic stirring in a water bath to obtain a dispersion; ② Add Dupont Nafion D520 solution (polymer concentration 5%) and n-propanol to the above dispersion in sequence, and perform planetary ball milling at 1500 r / min for more than 30 minutes to obtain a mixture; ③ After ball milling, further disperse the mixture with a 40 kHz ultrasonic stirring rod for 10 minutes, with a dispersion frequency of 5 seconds of dispersion and 3 seconds of pause; ④ Put the further dispersed mixture into a high-speed 2000 r / min centrifugal defoamer for 20 seconds to obtain the anode catalytic layer ink; wherein, the mass ratio of iridium oxide particles, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:2.5:0.8:50;

[0053] 4. Preparation of the cathode catalytic layer ink: The preparation method is the same as that of the anode catalytic layer ink, except that a nano-scale platinum-on-carbon catalyst of the TKKTEC10E60TPM model is used to replace the nano-scale iridium oxide particles, and the mass ratio of the nano-scale platinum-on-carbon catalyst, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:7:7:50;

[0054] 5. Coat the anodic catalyst layer ink and the cathodic catalyst layer ink on one side of two 200-mesh titanium meshes by ultrasonic spraying respectively. The iridium oxide loading of the anode is 0.7 mg / cm 2 , and the platinum loading of the cathode is 0.25 mg / cm 2 to form the anodic catalyst layer and the cathodic catalyst layer respectively;

[0055] 6. Cover the surface of the anodic catalyst layer and the surface of the cathodic catalyst layer with Dupont Nafion D520 solution by a spray pen. The polymer loading is 0.1 mg / cm 2 to form the Nafion layer and obtain the cathode electrode and the anode electrode;

[0056] 7. Let the cathode electrode and the anode electrode stand and be shaped at 130 °C for 10 min with the side of the catalyst layer and the Nafion layer facing up to obtain the cathode electrode and the anode electrode respectively;

[0057] 8. Place the electrodes under a scanning electron microscope and magnify them 200 times to observe and judge the spraying effect.

[0058] 9. At 130 °C, hot-press the cathode electrode and the anode electrode onto both sides of the proton exchange membrane obtained in step 2 at a pressure of 5 MPa respectively to obtain the PEMEC five-in-one electrode.

[0059] Install the PEMEC five-in-one electrode into the electrolytic cell fixture for performance testing.

[0060] Comparative Example 1

[0061] This comparative example provides a PEMEC five-in-one electrode, which is prepared by the following method:

[0062] 1. Pretreatment of the catalyst layer skeleton: Select a TA1 type titanium mesh with a thickness of 200 μm and 200 meshes as the anodic catalyst layer skeleton and the cathodic catalyst layer skeleton, and conduct electroplating treatment with platinum metal. The electroplating thickness is 500 nm;

[0063] 2. Pretreatment of the proton exchange membrane: Conduct hot-pressing treatment on the proton exchange membrane. The hot-pressing temperature is 110 °C, the pressure is 10 MPa, and the hot-pressing time is 3 minutes;

[0064] 3. Preparation of Anode Catalyst Layer Ink: ① Mix nano-sized iridium oxide particles with a particle size of 2 - 20 nm and deionized water at room temperature of 25 °C, and disperse them for 3 minutes by ultrasonic stirring in a water bath to obtain a dispersion; ② Add Dupont Nafion D520 solution (polymer concentration 5%) and n-propanol solvent to the above dispersion in sequence, and perform planetary ball milling at 1500 r / min for more than 30 minutes to obtain a mixture; ③ Put the mixture into a high-speed centrifugal defoamer at 2000 r / min for 20 seconds to remove bubbles, and obtain the anode catalyst layer ink; among them, the mass ratio of iridium oxide particles, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:2.5:0.8:50;

[0065] 4. Preparation of Cathode Catalyst Layer Ink: The preparation method is the same as that of the anode catalyst layer ink, except that the nano-sized platinum-on-carbon catalyst of the TKKTEC10E60TPM model is used to replace the nano-sized iridium oxide particles. Among them, the ratio of the nano-sized platinum-on-carbon catalyst, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:7:7:50;

[0066] 5. Coat the above anode catalyst layer ink and cathode catalyst layer ink on one side of two 200-mesh titanium meshes by ultrasonic spraying respectively. The iridium loading of the anode is 0.7 mg / cm 2 , and the platinum loading of the cathode is 0.25 mg / cm 2 , respectively forming an anode catalyst layer and a cathode catalyst layer;

[0067] 6. Cover the surfaces of the anode catalyst layer and the cathode catalyst layer with Dupont Nafion D520 solution by a spraying pen. The polymer loading is 0.1 mg / cm 2 , forming a Nafion layer to obtain a cathode electrode and an anode electrode;

[0068] 7. Let the cathode electrode and the anode electrode stand and be shaped at 130 °C for 10 minutes with the catalyst layer and the Nafion layer facing up respectively to obtain a cathode electrode and an anode electrode;

[0069] 8. At 130 °C, hot press the cathode electrode and the anode electrode onto both sides of the proton exchange membrane obtained in step 2 at a pressure of 5 MPa respectively, thereby obtaining a PEMEC five-in-one electrode.

[0070] Install the PEMEC five-in-one electrode into an electrolytic cell fixture for performance testing.

[0071] Example 2

[0072] This example provides a PEMEC five-in-one electrode, which is prepared by the following method:

[0073] 1. Pretreatment of the catalytic layer skeleton: Select a TA1 type titanium mesh with a thickness of 200 μm and a mesh size of 200 as the anode catalytic layer skeleton and the cathode catalytic layer skeleton, and perform electroplating of platinum metal. The electroplating thickness is 500 nm;

[0074] 2. Pretreatment of the proton exchange membrane: Perform hot pressing on the proton exchange membrane of the FUMA-FS-990-PK model. The hot pressing temperature is 110 °C, the pressure is 10 MPa, and the hot pressing time is 3 min;

[0075] 3. Preparation of the anode catalytic layer ink: ① Mix iridium oxide particles with a particle size of 2 - 20 nm and deionized water at room temperature of 25 °C, and disperse them for 3 minutes by water bath ultrasonic stirring to obtain a dispersion; ② Add Dupont Nafion D520 solution (polymer concentration 5%) and n-propanol to the above dispersion in sequence, and perform planetary ball milling at 1500 r / min for more than 30 min to obtain a mixture; ③ After ball milling, further disperse the mixture with a 40 kHz ultrasonic stirring rod for 10 min, and the dispersion frequency is 5 seconds of dispersion and 3 seconds of pause; ④ Put the further dispersed mixture into a high-speed 2000 r / min centrifugal defoamer for 20 seconds to obtain the anode catalytic layer ink; among them, the mass ratio of iridium oxide particles, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:2.5:0.8:50;

[0076] 4. Preparation of the cathode catalytic layer ink: The preparation method is the same as that of the anode catalytic layer ink, except that the TKK TEC10E60TPM model of nano-scale platinum-on-carbon catalyst is used to replace the nano-scale iridium oxide particles. Among them, the mass ratio of nano-scale platinum-on-carbon catalyst, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:7:7:50;

[0077] 5. Coat the above anode catalytic layer ink and cathode catalytic layer ink on one side of two 200-mesh titanium meshes (platinum-plated and non-platinum-plated) by ultrasonic spraying method respectively, and prepare the anode with an iridium loading of 0.5 mg / cm 2 、0.3 mg / cm 2 , and the cathode with a platinum loading of 0.25 mg / cm 2 respectively to form an anode catalytic layer and a cathode catalytic layer;

[0078] 6. Cover the surface of the anode catalytic layer and the surface of the cathode catalytic layer with Dupont Nafion D520 solution by a spraying pen. The polymer loading is 0.1 mg / cm 2 to form a Nafion layer, and obtain a cathode electrode and an anode electrode;

[0079] 7. Place the cathode electrode and the anode electrode on one side with the catalytic layer and the Nafion layer facing up and let them stand and be shaped at 130 °C for 10 min to obtain the cathode electrode and the anode electrode respectively.

[0080] 8. At 130 °C, press the cathode electrode and the anode electrode onto both sides of the proton exchange membrane obtained in step 2 under a pressure of 5 MPa respectively to obtain the PEMEC five-in-one electrode.

[0081] Install the PEMEC five-in-one electrode into the electrolytic cell fixture for ohmic impedance test and compare it with the commercial membrane electrode as Figure 5 shown.

[0082] Example 3

[0083] This example provides a PEMEC five-in-one electrode, which is prepared by the following method:

[0084] 1. Pretreatment of the catalytic layer skeleton: Select a TA1 type titanium mesh with a thickness of 200 μm and a mesh size of 200 as the anode catalytic layer skeleton and the cathode catalytic layer skeleton, and carry out electroplating of platinum metal with a plating thickness of 500 nm.

[0085] 2. Pretreatment of the proton exchange membrane: Carry out hot pressing treatment on the proton exchange membrane of the FUMA-FS-990-PK model, with a hot pressing temperature of 110 °C, a pressure of 10 MPa, and a hot pressing time of 3 min.

[0086] 3. Preparation of the anode catalytic layer ink: ① Mix iridium oxide particles with a particle size of 2 - 20 nm and deionized water at room temperature of 25 °C, and disperse them by water bath ultrasonic stirring for 3 minutes to obtain a dispersion; ② Add Dupont Nafion D520 solution (polymer concentration 5%) and n-propanol to the above dispersion in sequence, and carry out planetary ball milling at 1500 r / min for more than 30 min to obtain a mixture; ③ After ball milling, further disperse the mixture with a 40 kHz ultrasonic stirring rod for 10 min, with a dispersion frequency of 5 seconds of dispersion and 3 seconds of pause; ④ Put the further dispersed mixture into a high-speed 2000 r / min centrifugal defoamer for defoaming for 20 seconds to obtain the anode catalytic layer ink; among them, the mass ratio of iridium oxide particles, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:2.5:0.8:50.

[0087] 4. Preparation of the cathode catalytic layer ink: The preparation method is the same as that of the anode catalytic layer ink, the difference is that the nano-scale platinum-on-carbon catalyst of the TKKTEC10E60TPM model is used to replace the nano-scale iridium oxide particles, and the mass ratio of the nano-scale platinum-on-carbon catalyst, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:7:7:50.

[0088] 5. Coat the above-mentioned anode catalyst layer ink and cathode catalyst layer ink on one side of two 200-mesh titanium meshes by ultrasonic spraying respectively. The iridium oxide loading of the anode is 0.7 mg / cm 2 , and the platinum loading of the cathode is 0.25 mg / cm 2 to form the anode catalyst layer and the cathode catalyst layer respectively;

[0089] 6. Cover the surface of the anode catalyst layer and the surface of the cathode catalyst layer with Dupont Nafion D520 solution by a spraying pen. The polymer loading is 0.1 mg / cm 2 to form the Nafion layer and obtain the cathode electrode and the anode electrode;

[0090] 7. Let the cathode electrode and the anode electrode stand for shaping at 130 °C for 10 min with the catalyst layer and the Nafion layer facing up respectively to obtain the cathode electrode and the anode electrode respectively;

[0091] 8. At 110 °C, press the cathode electrode and the anode electrode onto both sides of the proton exchange membrane obtained in step 2 under a pressure of 2 MPa respectively to obtain the PEMEC five-in-one electrode.

[0092] Install the five-in-one electrode into the electrolytic cell fixture for performance testing. The performance of the PEMEC five-in-one electrode reaches 2 V@3.2 A / cm 2 .

[0093] Comparative Example 2

[0094] This comparative example provides a PEMEC five-in-one electrode, which is prepared by the following method:

[0095] 1. Pretreatment of the catalyst layer skeleton: Select a TA1 type titanium mesh with a thickness of 200 μm and 200 meshes as the anode catalyst layer skeleton and the cathode catalyst layer skeleton, and perform electroplating of platinum metal. The electroplating thickness is 500 nm;

[0096] 2. Pretreatment of the proton exchange membrane: Perform hot pressing on the proton exchange membrane. The hot pressing temperature is 110 °C, the pressure is 10 MPa, and the hot pressing time is 3 min;

[0097] 3. Preparation of Anode Catalyst Layer Ink: ① Mix iridium oxide particles with a particle size of 2 - 20 nm and deionized water at room temperature of 25 °C, and disperse them for 3 minutes by water bath ultrasonic stirring to obtain a dispersion; ② Add Dupont Nafion D520 solution (polymer concentration 5%) and n-propanol solvent to the above dispersion in sequence, and perform planetary ball milling at 1500 r / min for more than 30 minutes to obtain a mixture; ③ After ball milling, further disperse the mixture with a 40 kHz ultrasonic stirring rod for 10 minutes, with a dispersion frequency of 5 seconds of dispersion and 3 seconds of pause; ④ Put the further dispersed mixture into a high-speed centrifugal defoamer at 2000 r / min for 20 seconds to obtain the anode catalyst layer ink; among them, the mass ratio of iridium oxide particles, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:2.5:0.8:50;

[0098] 4. Preparation of Cathode Catalyst Layer Ink: The preparation method is the same as that of the anode catalyst layer ink, except that the nano-scale platinum-on-carbon catalyst of the TKKTEC10E60TPM model is used to replace the nano-scale iridium oxide particles. Among them, the mass ratio of the nano-scale platinum-on-carbon catalyst, Dupont Nafion D520 solution, deionized water, and n-propanol is 1:7:7:50;

[0099] 5. Coat the above anode catalyst layer ink and cathode catalyst layer ink on one side of two 200-mesh titanium meshes by ultrasonic spraying respectively. The iridium loading of the anode is 0.7 mg / cm 2 , and the platinum loading of the cathode is 0.25 mg / cm 2 , respectively forming an anode catalyst layer and a cathode catalyst layer;

[0100] 6. Cover the surface of the anode catalyst layer and the surface of the cathode catalyst layer with Dupont Nafion D520 solution by a spraying pen. The polymer loading is 0.1 mg / cm 2 , forming a Nafion layer to obtain a cathode electrode and an anode electrode;

[0101] 7. Let the cathode electrode and the anode electrode stand and be shaped at 130 °C for 10 minutes with the catalyst layer and the Nafion layer facing up respectively to obtain a cathode electrode and an anode electrode;

[0102] 8. At 150 °C, hot press the cathode electrode and the anode electrode onto both sides of the proton exchange membrane obtained in step 2 at a pressure of 8 MPa respectively, thereby obtaining a PEMEC five-in-one electrode.

[0103] Install the PEMEC five-in-one electrode into an electrolytic cell fixture for performance testing. After analysis, a pressure of 6 MPa will pierce the membrane, causing electrode short circuit.

[0104] Comparative Example 3

[0105] This comparative example provides an electrolytic water hydrogen production membrane electrode with a traditional CCM configuration, whose structure is a proton exchange membrane uniformly coated with catalyst layers on both sides. Specifically, it is prepared through the following steps:

[0106] 1. Prepare the anode catalyst slurry: The catalyst slurry is composed of IrO2 catalyst particles, 5% concentration Nafion solution, pure water, and n-propanol according to a mass ratio of 1:2.5:0.8:50, and the catalyst particles are uniformly dispersed in the slurry by combining ball milling and ultrasonic dispersion;

[0107] 2. Prepare the uniformly supported anode catalyst layer: The anode catalyst slurry is sprayed on the surface of the proton exchange membrane through an ultrasonic sprayer to form a uniform anode catalyst layer, and the catalyst loading is 1 mg / cm 2 ;

[0108] 3. Prepare the cathode catalyst slurry: The specific preparation process is the same as that of the anode catalyst slurry, except that: the carbon-supported platinum catalyst is used to replace the IrO2 particles. Among them, the mass ratio of the carbon-supported platinum catalyst (Pt loading is 60 wt%), 5% concentration Nafion solution, deionized water, and n-propanol is 1:7:7:50;

[0109] 4. Prepare the uniformly supported cathode catalyst layer: The cathode catalyst slurry is sprayed on the other side surface of the proton exchange membrane through an ultrasonic sprayer to form a uniform cathode catalyst layer, and the cathode catalyst loading is 0.2 mg / cm 2 .

[0110] Figure 1 is the scanning electron microscope image of the PTE electrode prepared in Example 1, Figure 2 is the scanning electron microscope image of the PTE electrode prepared in Comparative Example 1. It can be seen from the comparison between Figure 1 and Figure 2 that: Comparative Example 1 lacks a step of ultrasonic dispersion, and ball milling alone for the slurry is not enough, and the particles are unevenly dispersed; in Example 1, after ball milling, the mixed liquid is further dispersed by an ultrasonic stirrer at 40 kHz, which can achieve better dispersion of the catalyst ink, so that it can be more evenly distributed after being sprayed onto the titanium mesh, and problems such as flash and burrs will not occur.

[0111] Figure 3 is the scanning electron microscope image of the electrodes prepared under different pressures. It can be seen from Figure 3 that: when the temperature is too high, the proton exchange membrane will deform; when the pressure is too large, it can be seen from the local enlarged view that the wire mesh has been embedded into the membrane, reducing the membrane thickness, which will reduce the durability of the membrane.

[0112] Figure 4Schematic diagram of the CCM-form membrane electrode with uniform loading (diagram (a)) and the PTE-form electrode prepared by the present invention (diagram (b)). By Figure 4 It can be seen that the catalyst utilization rate of the CCM-form membrane electrode is lower than that of the PTE-form electrode.

[0113] Figure 5 Performance comparison results of the PTE electrode prepared in Example 2 and the traditional CCM electrode. Among them, PTE-0.3mg / cm 2 corresponds to the technical solution without platinum plating and the iridium oxide loading on the anode is 0.3mg / cm 2 ; PTE (platinum-plated)-0.3mg / cm 2 corresponds to the technical solution with platinum plating and the iridium oxide loading on the anode is 0.3mg / cm 2 ; PTE-0.5mg / cm 2 corresponds to the technical solution without platinum plating and the iridium oxide loading on the anode is 0.5mg / cm 2 ; PTE (platinum-plated)-0.5mg / cm 2 corresponds to the technical solution with platinum plating and the iridium oxide loading on the anode is 0.5mg / cm 2 ; CCM-1mg / cm 2 corresponds to the traditional CCM electrode of Comparative Example 3.

[0114] From Figure 5 the results shown, it can be seen that the PTE electrode of the present invention has lower ohmic impedance and higher current corresponding to the catalyst per unit mass. Therefore, the PTE electrode has a more efficient catalyst utilization rate compared to the traditional CCM electrode. Therefore, under the same performance, the PTE electrode requires less catalyst.

Claims

1. A method for preparing a PEMEC five-in-one electrode, comprising the following steps: Electroplating the titanium mesh with metal to form an electroplating layer to obtain a catalytic layer skeleton; Anode catalyst layer ink and cathode catalyst layer ink are prepared, wherein the anode catalyst layer ink is made of nano-scale iridium oxide catalyst, Nafion solution, deionized water, and solvent, wherein the mass ratio of the polymer material in the Nafion solution to the nano-scale iridium oxide catalyst is (0.125-0.5):1, and the solid content of the anode catalyst layer ink is 1%-5%; the cathode catalyst layer ink is made of nano-scale carbon-supported platinum catalyst, Nafion solution, deionized water, and solvent, wherein the mass ratio of the polymer material in the Nafion solution to the carbon carrier of the nano-scale carbon-supported platinum catalyst is (0.35-1):1, and the solid content of the cathode catalyst layer ink is 1%-2%; The anode catalyst layer ink and the cathode catalyst layer ink are respectively sprayed onto one side of the catalyst layer skeleton by ultrasonic spraying to form the anode catalyst layer and the cathode catalyst layer respectively; Covering the surface of the anode catalyst layer and the surface of the cathode catalyst layer with Nafion solution respectively to form a Nafion layer, thereby obtaining a cathode electrode and an anode electrode; The cathode electrode and the anode electrode are respectively placed in a static state with the catalyst layer and the Nafion layer facing upward to obtain a negative electrode and a positive electrode respectively; The cathode electrode and the anode electrode are respectively hot-pressed and laminated to the two sides of the proton exchange membrane that has been hot-pressed to obtain the PEMEC five-in-one electrode; The anode catalyst layer ink is prepared by the following steps: mixing nano-sized iridium oxide particles and deionized water, and dispersing them by ultrasonic stirring in a water bath to obtain a dispersion; sequentially adding a Nafion solution and a solvent to the dispersion, and performing ball milling to obtain a mixed solution; performing ultrasonic stirring and dispersion on the mixed solution to obtain a further dispersed mixed solution, and then performing a degassing treatment on the further dispersed mixed solution to obtain the anode catalyst layer ink; The cathode catalyst layer ink is prepared by the following steps: mixing a nano-scale carbon-supported platinum catalyst and deionized water, and dispersing them by ultrasonic stirring in a water bath to obtain a dispersion; sequentially adding a Nafion solution and a solvent to the dispersion, and performing ball milling to obtain a mixed solution; performing ultrasonic stirring and dispersion on the mixed solution to obtain a further dispersed mixed solution, and then performing a degassing treatment on the further dispersed mixed solution to obtain a cathode catalyst layer ink; The temperature of the hot pressing compound is 110-130° C. and the pressure is 2-5 MPa.

2. The preparation method according to claim 1, wherein The titanium mesh is a TA1 type titanium mesh.

3. The preparation method according to claim 2, wherein The titanium mesh is plain or twill woven, and has a pore size of 50-600 meshes.

4. The preparation method according to claim 3, wherein The pore size is 200 mesh.

5. The preparation method according to claim 1, wherein The solvent is n-propanol.

6. The preparation method according to claim 1, wherein The water bath ultrasonic stirring time is 3-5 minutes; The ball milling adopts a planetary ball milling method, with a rotation speed of 300-1500r / min and a time of 0.5-3 hours; The degassing is carried out by centrifugal degassing, the centrifugal speed is 2000-2200r / min, and the time is 15-20 seconds.

7. The preparation method according to claim 1, wherein The dispersion frequency of the ultrasonic stirring dispersion is 5 seconds for dispersion and 3 seconds for rest.

8. The preparation method according to claim 1, wherein The ultrasonic frequency of the ultrasonic stirring and dispersing is 20-40 kHz.

9. The preparation method according to claim 1, wherein The ultrasonic stirring and dispersing time is 10-15 minutes.

10. The preparation method according to claim 1, wherein: The ultrasonic spraying nozzle has an ultrasonic frequency of 25-180 kHz.

11. The preparation method according to claim 1, wherein The thickness of the anode catalyst layer is 0.8-2 μm; the thickness of the cathode catalyst layer is 6-10 μm.

12. The preparation method according to claim 1, wherein: The thickness of the electroplating layer is 500nm.

13. The preparation method according to claim 1, wherein The thickness of the Nafion layer is 0.5-1 μm.

14. The preparation method according to claim 1, wherein: The hot-pressed proton exchange membrane is obtained by hot-pressing the proton exchange membrane under the conditions of a temperature of 100-120° C. and a pressure of 8-12 MPa.

15. The preparation method according to claim 1, wherein: The temperature of the static molding is 130° C. and the time is 10 minutes.

16. A PEMEC five-in-one electrode, prepared by the preparation method according to any one of claims 1 to 15.

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