Direct methanol fuel cell membrane electrode structure based on transfer printing method and preparation method thereof

Abstract

The invention relates to a direct methanol fuel cell membrane electrode structure based on a transfer printing method and a preparation method of the direct methanol fuel cell membrane electrode structure. The anode catalyst layer is attached to one side of the proton exchange membrane, and the anode gas diffusion layer is hot-pressed on the outer side of the anode catalyst layer; the cathode catalyst layer is attached to the other side of the proton exchange membrane; and the cathode gas diffusion layer is hot-pressed on the outer side of the cathode catalyst layer.

Description

Technical Field

[0001] This invention relates to the field of direct methanol fuel cells, and to a membrane electrode structure for direct methanol fuel cells based on a transfer printing method, and more particularly to a membrane electrode structure for direct methanol fuel cells based on a transfer printing method and its preparation method. Background Technology

[0002] A direct methanol fuel cell (DMFC) is an electrochemical energy conversion device that directly converts the chemical energy of liquid methanol into electrical energy without the need for external hydrogen reforming. DMFCs offer advantages such as simple system structure, high methanol fuel energy density, convenient refueling, environmental friendliness, and rapid start-up, making them widely used in portable power supplies, transportation, and telecommunications base stations.

[0003] Currently, the main methods for preparing DMFC membrane electrodes include the following two: Gas Diffusion Electrode (GDE): The catalyst slurry is loaded onto the surface of the gas diffusion layer by means of coating, spraying, scraping or screen printing, and then hot-pressed with a proton exchange membrane to form a membrane electrode.

[0004] Disadvantages of the GDE method: low catalyst utilization, with some catalyst permeating into the gas diffusion layer and causing waste; weak bonding between the catalyst layer and the proton exchange membrane, high interfacial resistance, and easy delamination after hot pressing, leading to a decline in membrane electrode performance.

[0005] Catalyst Coated Membrane (CCM): The catalyst slurry is directly loaded onto both sides of the proton exchange membrane by means of deposition, spraying or direct coating, and then hot-pressed with the gas diffusion layer to form a membrane electrode.

[0006] Disadvantages of CCM method: proton exchange membranes are prone to swelling during wet coating process, the catalyst layer is prone to cracking, batch consistency is poor, which affects the durability of membrane electrodes and large-scale production. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention aims to provide a direct methanol fuel cell membrane electrode structure based on the transfer printing method and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A membrane electrode structure for a direct methanol fuel cell based on a transfer printing method includes, Proton exchange membrane; An anode catalyst layer, which is attached to one side of the proton exchange membrane. An anode gas diffusion layer is hot-pressed onto the outside of the anode catalyst layer; A cathode catalytic layer, which is attached to the other side of the proton exchange membrane; A cathode gas diffusion layer is hot-pressed onto the outside of the cathode catalyst layer.

[0009] Preferably, in the direct methanol fuel cell membrane electrode structure based on the transfer method, the Pt loading in the anode catalyst layer is 3.0–5.0 mg / cm².

[0010] Preferably, in the direct methanol fuel cell membrane electrode structure based on the transfer method, the Pt loading in the cathode catalyst layer is 2.0–4.0 mg / cm².

[0011] A method for preparing a membrane electrode assembly for a direct methanol fuel cell based on a transfer printing method. Includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10-15g of Pt / C catalyst with 40-80g of deionized water to completely wet the catalyst. Then add 20-50g of isopropanol and 20-50g of Nafion resin solution. Disperse ultrasonically for 30 minutes, and then disperse at 20,000 rpm for 10 minutes in a high-shear emulsifier to obtain a cathode catalyst slurry with a solid content of 10-20 wt%. Step 2: Prepare the anode catalyst slurry. Mix 10-20g of PtRu / C catalyst with 30-50g of deionized water to completely wet the catalyst. Then add 10-20g of isopropanol and 20-50g of Nafion resin solution. Disperse ultrasonically for 30 minutes, and then disperse at 20,000 rpm for 10 minutes in a high-shear emulsifier to obtain an anode catalyst slurry with a solid content of 15-30 wt%. Step 3: Coating and drying. Use a slot coater to coat the cathode and anode catalyst slurries onto the transfer substrate, and dry them at 80-110℃ to form self-supporting cathode and anode catalyst film. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 130-150℃ and 1.0-2.0MPa for 2-5 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press for 5–10 minutes at 100–130℃ and 1.0–2.0MPa. Cool to room temperature to obtain a five-layer CCM film electrode.

[0012] Preferably, in the method for preparing a direct methanol fuel cell membrane electrode based on the transfer method, the substrate comprises polytetrafluoroethylene (PTFE) and polyimide (PI).

[0013] Preferably, in the method for preparing a direct methanol fuel cell membrane electrode based on the transfer method, the Pt loading in the anode catalyst layer is 3.0–5.0 mg / cm².

[0014] Preferably, in the method for preparing a direct methanol fuel cell membrane electrode based on the transfer method, the Pt loading in the cathode catalyst layer is 2.0–4.0 mg / cm².

[0015] Preferably, the method for preparing a direct methanol fuel cell membrane electrode based on the transfer method includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10g of Pt / C catalyst with 50g of deionized water to completely wet the catalyst. Then add 30g of isopropanol and 20g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the cathode catalyst slurry. Step 2: Prepare the anode catalyst slurry. Mix 10g of PtRu / C catalyst with 30g of deionized water to completely wet the catalyst. Then add 20g of isopropanol and 30g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the anode catalyst slurry. Step 3: Coating and drying. The cathode and anode catalyst slurries are coated onto the transfer substrate using a slot coater and dried at 80°C to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 130℃ and 1.0MPa for 5 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press them at 100℃ and 1.0MPa for 10 minutes. Cool to room temperature to obtain a five-layer CCM film electrode.

[0016] Preferably, the method for preparing a direct methanol fuel cell membrane electrode based on the transfer method includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10g of Pt / C catalyst with 50g of deionized water to completely wet the catalyst. Then add 30g of isopropanol and 20g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the cathode catalyst slurry. Step 2: Prepare the anode catalyst slurry. Mix 10g of PtRu / C catalyst with 30g of deionized water to completely wet the catalyst. Then add 20g of isopropanol and 30g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the anode catalyst slurry. Step 3: Coating and drying. The cathode and anode catalyst slurries are coated onto the transfer substrate using a slot coater and dried at 110°C to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 150℃ and 2.0MPa for 2 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press them at 130℃ and 2.0MPa for 5 minutes. Cool to room temperature to obtain a five-layer CCM film electrode.

[0017] Preferably, the method for preparing a direct methanol fuel cell membrane electrode based on the transfer method involves preparing cathode and anode catalyst slurries separately, slit-coating them onto a PTFE transfer substrate, wherein the Pt loading in the anode catalyst layer is 4.0 mg / cm², and the Pt loading in the cathode catalyst layer is 3.0 mg / cm². After drying at 80°C, the slurries are hot-pressed with a proton exchange membrane at 140°C, 1 MPa, and 5 min to form a three-layer membrane electrode structure. Then, the three-layer membrane electrode, along with the cathode and anode gas diffusion layers, are hot-pressed at 120°C, 1 MPa, and 10 min to form a five-layer membrane electrode structure; at 0.30 A / cm². 2The power density at the current density is 0.18 W / cm2, and the power after 5000 hours of operation is 0.162 W / cm2, with a decay rate of 10%.

[0018] By means of the above-described solution, the present invention has at least the following advantages: The membrane electrode structure of this invention effectively reduces the interfacial resistance, and increases the power density by about 20% at a current density of 0.30 A / cm². After 5000 hours of operation, the power decay rate is reduced from 30% to 10%, and the durability is significantly improved. It avoids the swelling problem of proton exchange membranes, has strong catalytic layer adhesion, and high surface smoothness. The process is suitable for continuous production and has good batch consistency.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] Example 1 like Figure 1 As shown, a membrane electrode structure for a direct methanol fuel cell based on a transfer printing method includes, Proton exchange membrane 1; Anode catalyst layer 2, which is attached to one side of proton exchange membrane 1. Anode gas diffusion layer 3 is hot-pressed onto the outside of anode catalyst layer 2; A cathode catalytic layer 4 is attached to the other side of the proton exchange membrane 1; The cathode gas diffusion layer 5 is hot-pressed onto the outside of the cathode catalyst layer 4.

[0025] In Example 1, the Pt loading in the anode catalyst layer 2 is 3.0–5.0 mg / cm².

[0026] In Example 1, the Pt loading in the cathode catalyst layer 4 is 2.0–4.0 mg / cm².

[0027] A method for preparing a membrane electrode assembly for a direct methanol fuel cell based on a transfer printing method includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10-15g of Pt / C catalyst with 40-80g of deionized water to completely wet the catalyst. Then add 20-50g of isopropanol and 20-50g of Nafion resin solution. Disperse ultrasonically for 30 minutes, and then disperse at 20,000 rpm for 10 minutes in a high-shear emulsifier to obtain a cathode catalyst slurry with a solid content of 10-20 wt%. Step 2: Prepare the anode catalyst slurry. Mix 10-20g of PtRu / C catalyst with 30-50g of deionized water to completely wet the catalyst. Then add 10-20g of isopropanol and 20-50g of Nafion resin solution. Disperse ultrasonically for 30 minutes, and then disperse at 20,000 rpm for 10 minutes in a high-shear emulsifier to obtain an anode catalyst slurry with a solid content of 15-30 wt%. Step 3: Coating and drying. Use a slot coater to coat the cathode and anode catalyst slurries onto the transfer substrate, and dry them at 80-110℃ to form self-supporting cathode and anode catalyst film. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 130-150℃ and 1.0-2.0MPa for 2-5 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press for 5–10 minutes at 100–130℃ and 1.0–2.0MPa. Cool to room temperature to obtain a five-layer CCM film electrode.

[0028] The substrate includes polytetrafluoroethylene (PTFE) and polyimide (PI).

[0029] Example 2 Based on Example 1, a method for preparing a membrane electrode for a direct methanol fuel cell using a transfer method includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10g of Pt / C catalyst with 50g of deionized water to completely wet the catalyst. Then add 30g of isopropanol and 20g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the cathode catalyst slurry. Step 2: Prepare the anode catalyst slurry. Mix 10g of PtRu / C catalyst with 30g of deionized water to completely wet the catalyst. Then add 20g of isopropanol and 30g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the anode catalyst slurry. Step 3: Coating and drying. The cathode and anode catalyst slurries are coated onto the transfer substrate using a slot coater and dried at 80°C to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 130℃ and 1.0MPa for 5 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press them at 100℃ and 1.0MPa for 10 minutes. Cool to room temperature to obtain a five-layer CCM film electrode.

[0030] Example 3 Based on Example 1, a method for preparing a membrane electrode for a direct methanol fuel cell using a transfer method includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10g of Pt / C catalyst with 50g of deionized water to completely wet the catalyst. Then add 30g of isopropanol and 20g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the cathode catalyst slurry. Step 2: Prepare the anode catalyst slurry. Mix 10g of PtRu / C catalyst with 30g of deionized water to completely wet the catalyst. Then add 20g of isopropanol and 30g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the anode catalyst slurry. Step 3: Coating and drying. The cathode and anode catalyst slurries are coated onto the transfer substrate using a slot coater and dried at 110°C to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 150℃ and 2.0MPa for 2 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press them at 130℃ and 2.0MPa for 5 minutes. Cool to room temperature to obtain a five-layer CCM film electrode.

[0031] Example 4 Based on Example 1, a method for preparing a membrane electrode assembly for a direct methanol fuel cell using a transfer printing method is provided. Cathode and anode catalyst slurries are prepared separately and slit-coated onto a PTFE transfer substrate. The Pt loading in the anode catalyst layer is 4.0 mg / cm³. 2 The cathode catalyst layer has a Pt loading of 3.0 mg / cm². After drying at 80 °C, it is hot-pressed with a proton exchange membrane at 140 °C, 1 MPa, and 5 min to form a three-layer membrane electrode structure. Then, the three-layer membrane electrode, the cathode and anode gas diffusion layers are hot-pressed at 120 °C, 1 MPa, and 10 min to form a five-layer membrane electrode structure. The power density at a current density of 0.30 A / cm² is 0.18 W / cm², and the power after 5000 h of operation is 0.162 W / cm², with a decay rate of 10%.

[0032] Comparative Example Compared with Example 4: Cathode and anode catalyst slurries were prepared separately and slit-coated onto a proton exchange membrane. The Pt loading in the anode catalyst layer was 4.0 mg / cm³. 2 The Pt loading in the cathode catalyst layer is 3.0 mg / cm³. 2 After drying at 80℃, a three-layer film electrode structure was obtained. Then, the three-layer film electrode, along with the cathode and anode gas diffusion layers, were hot-pressed at 120℃, 1MPa, and 10min to form a five-layer film electrode structure. The pressure was 0.30 A / cm. 2 The power density at the current density is 0.15 W / cm². 2 The power consumption after 5000 hours of operation is 0.105 W / cm². 2 The attenuation rate is 30%.

[0033] The final results from Example 4 and the comparative example show that the power density and attenuation rate in the comparative example are higher than those in Example 4, indicating that the membrane electrode structure proposed in this invention effectively reduces the interface resistance and effectively improves the power density and durability of the membrane electrode.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this application, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or vertical, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0037] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A membrane electrode structure for a direct methanol fuel cell based on a transfer printing method, characterized in that: include, Proton exchange membrane (1); An anode catalyst layer (2) is attached to one side of the proton exchange membrane (1). Anode gas diffusion layer (3), which is hot-pressed onto the outside of anode catalyst layer (2); A cathode catalyst layer (4) is attached to the other side of the proton exchange membrane (1); A cathode gas diffusion layer (5) is hot-pressed onto the outside of the cathode catalyst layer (4).

2. The membrane electrode structure for a direct methanol fuel cell based on the transfer method according to claim 1, characterized in that: The Pt loading in the anode catalyst layer (2) is 3.0–5.0 mg / cm².

3. The membrane electrode structure for a direct methanol fuel cell based on the transfer method according to claim 1, characterized in that: The Pt loading in the cathode catalyst layer (4) is 2.0–4.0 mg / cm².

4. A method for preparing a membrane electrode assembly for a direct methanol fuel cell based on a transfer printing method, characterized in that, Includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10-15g of Pt / C catalyst with 40-80g of deionized water to completely wet the catalyst. Then add 20-50g of isopropanol and 20-50g of Nafion resin solution. Disperse ultrasonically for 30 minutes, and then disperse at 20,000 rpm for 10 minutes in a high-shear emulsifier to obtain a cathode catalyst slurry with a solid content of 10-20 wt%. Step 2: Prepare the anode catalyst slurry. Mix 10-20g of PtRu / C catalyst with 30-50g of deionized water to completely wet the catalyst. Then add 10-20g of isopropanol and 20-50g of Nafion resin solution. Disperse ultrasonically for 30 minutes, and then disperse at 20,000 rpm for 10 minutes in a high-shear emulsifier to obtain an anode catalyst slurry with a solid content of 15-30 wt%. Step 3: Coating and drying. Use a slot coater to coat the cathode and anode catalyst slurries onto the transfer substrate, and dry them at 80-110℃ to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 130-150℃ and 1.0-2.0MPa for 2-5 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press for 5–10 minutes at 100–130℃ and 1.0–2.0MPa. Cool to room temperature to obtain a five-layer CCM film electrode.

5. The method for preparing a direct methanol fuel cell membrane electrode based on the transfer method according to claim 4, characterized in that: The substrate includes polytetrafluoroethylene (PTFE) and polyimide (PI).

6. The method for preparing a direct methanol fuel cell membrane electrode based on the transfer method according to claim 4, characterized in that: The Pt loading in the anode catalyst layer (2) is 3.0–5.0 mg / cm².

7. The method for preparing a direct methanol fuel cell membrane electrode based on the transfer method according to claim 4, characterized in that: The Pt loading in the cathode catalyst layer (4) is 2.0–4.0 mg / cm².

8. A method for preparing a direct methanol fuel cell membrane electrode based on a transfer method according to any one of claims 4 to 7, characterized in that: Includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10g of Pt / C catalyst with 50g of deionized water to completely wet the catalyst. Then add 30g of isopropanol and 20g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the cathode catalyst slurry. Step 2: Prepare the anode catalyst slurry. Mix 10g of PtRu / C catalyst with 30g of deionized water to completely wet the catalyst. Then add 20g of isopropanol and 30g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the anode catalyst slurry. Step 3: Coating and drying. The cathode and anode catalyst slurries are coated onto the transfer substrate using a slot coater and dried at 80°C to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 130℃ and 1.0MPa for 5 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press them at 100℃ and 1.0MPa for 10 minutes. Cool to room temperature to obtain a five-layer CCM film electrode.

9. A method for preparing a direct methanol fuel cell membrane electrode based on a transfer method according to any one of claims 4 to 7, characterized in that... ； Includes the following steps: Step 1: Prepare the cathode catalyst slurry. Mix 10g of Pt / C catalyst with 50g of deionized water to completely wet the catalyst. Then add 30g of isopropanol and 20g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the cathode catalyst slurry. Step 2: Prepare the anode catalyst slurry. Mix 10g of PtRu / C catalyst with 30g of deionized water to completely wet the catalyst. Then add 20g of isopropanol and 30g of Nafion resin solution, and ultrasonically disperse for 30 minutes. Then disperse for 10 minutes at 20,000 rpm in a high-shear emulsifier to obtain the anode catalyst slurry. Step 3: Coating and drying. The cathode and anode catalyst slurries are coated onto the transfer substrate using a slot coater and dried at 110°C to form self-supporting cathode and anode catalyst thin films. Step 4: Hot pressing transfer. Place the cathode and anode catalyst film on both sides of the proton exchange membrane and align and stack them. Hot press at 150℃ and 2.0MPa for 2 minutes to detach the cathode and anode catalyst layers from the substrate and firmly attach them to both sides of the proton exchange membrane. Step 5: Cooling and peeling. After the adhesion is completed in step 4, the transfer substrate is peeled off after cooling to below 40°C to obtain a three-layer CCM film electrode. Step 6: Assemble the hot-pressed gas diffusion layer. Place the cathode and anode gas diffusion layers on both sides of the three-layer CCM and hot-press them at 130℃ and 2.0MPa for 5 minutes. Cool to room temperature to obtain a five-layer CCM film electrode.

10. A method for preparing a direct methanol fuel cell membrane electrode based on a transfer method according to any one of claims 4 to 7, characterized in that: Cathode and anode catalyst slurries were prepared separately and slit-coated onto a PTFE transfer substrate. The Pt loading in the anode catalyst layer was 4.0 mg / cm³. 2 The Pt loading in the cathode catalyst layer is 3.0 mg / cm³. 2 After drying at 80℃, a three-layer membrane electrode structure was formed by hot-pressing the proton exchange membrane at 140℃, 1MPa, and 5min. Then, the three-layer membrane electrode, along with the cathode and anode gas diffusion layers, was hot-pressed at 120℃, 1MPa, and 10min to form a five-layer membrane electrode structure. (The last sentence appears to be incomplete and possibly refers to a specific temperature range: 0.30 A / cm².) 2 The power density at the current density is 0.18 W / cm². 2 The power consumption after 5000 hours of operation is 0.162 W / cm². 2 The attenuation rate is 10%.

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