Substrate capable of protecting conductive layer and preventing water logging and preparation method thereof

Abstract

The invention belongs to but not limited to the technical field of substrate preparation, and discloses a substrate capable of protecting a conductive layer and preventing water logging and a preparation method thereof. PTFE fiber with moderate density is selected as a base material; the high-purity metal Cu particles are polished through abrasive paper, and surface smudginess is removed; the polished metal particles are placed in an evaporation source corresponding to a vacuum chamber for thermal evaporation and fixed, the selected PTFE is pasted and placed above the evaporation source, and vacuum evaporation is carried out; depositing a first layer of metal film on the surface of the PTFE fiber by using a thermal evaporation technology; after the first time of metal coating is completed, a carbon black solution covers the coated PTFE surface through uniform spraying equipment, and a uniform middle layer is formed; and carrying out secondary metal coating on the carbon black layer to form a composite film structure. The carbon black in the middle layer can protect the conducting layer to maintain the smoothness of a circuit, and can also prevent water logging to ensure the smoothness of a gas channel, so that the stability of catalytic reaction is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of substrate preparation, and particularly relates to a substrate with a conductive layer and waterproofing function and a preparation method thereof. BACKGROUND

[0002] Since the industrial revolution, fossil fuels such as coal, oil and natural gas have been the main energy sources to support economic and social development, but fossil fuels have also brought many problems, and the massive emission of carbon dioxide is one of the most serious problems. At present, electrocatalytic reduction of carbon dioxide not only can greatly reduce the content of carbon dioxide in the atmosphere and reduce the greenhouse effect, but also can convert it into resources that can be used by the present application. In the early stage, copper or other metals were directly used as catalyst materials, but this was accompanied by a very serious hydrogen evolution reaction, which seriously reduced the efficiency of carbon dioxide reduction. Copper or other metals have no pores, which is obviously not conducive to gas diffusion, which also reduces the performance of the catalyst. Evaporating metal on a porous hydrophobic substrate PTFE becomes a common choice for everyone, although this can improve performance, but it does not solve the problem of catalyst stability. There are many reasons for the poor stability of the catalyst, and the destruction of the conductivity of the substrate and the waterlogging phenomenon that occurs during the reaction process are two of the most prominent ones. The destruction of the conductivity will cause the circuit to be not smooth during the reaction process, and the waterlogging will not only block the carbon dioxide gas channel, but also exacerbate the hydrogen evolution side reaction.

[0003] In the related prior art, prior art 1 discloses a method for depositing a single-layer metal film on the surface of a polymer substrate to achieve conductive function. The method forms a dense metal layer on the surface of a polyester or polyimide film by vacuum evaporation, which is used for the manufacture of flexible circuit substrates. This technology can ensure conductivity to some extent, but in a humid or liquid immersion environment, the single-layer metal film is easily affected by water vapor penetration and is prone to oxidation and corrosion, and the interfacial adhesion between the metal layer and the polymer matrix is insufficient, and cracks and peeling are likely to occur after bending fatigue, resulting in rapid decline in conductive performance.

[0004] Prior art 2 discloses a structure for covering a waterproof insulating coating on the surface of a metal layer to achieve moisture and immersion resistance. It forms a physical barrier to block the invasion of water by coating a polyurethane, epoxy or fluorinated polymer film on the surface of a copper or silver layer. This method is effective in terms of short-term waterproof performance, but the coating itself is not conductive, which reduces the surface conductivity of the overall structure, and under the action of long-term mechanical stress or repeated bending, the coating is prone to micro-cracks. Once damaged, the metal layer is directly exposed and loses its protective effect. In addition, the difference in the coefficient of thermal expansion between the coating and the metal layer is large, and the interface is prone to delamination under temperature and humidity cycles.

[0005] The prior art 1 is difficult to balance waterproof and corrosion resistance, and the prior art 2 has waterproof ability, but sacrifices the conductivity and is insufficient in stability in a long-term service environment. The present application realizes multi-level interface protection and the synergistic effect of the conductive network by constructing the composite structure of the first metal layer-the carbon black intermediate layer-the second metal layer on the PTFE fiber substrate, not only blocks the water vapor penetration path, but also maintains low interface resistance and good mechanical flexibility, thereby overcoming the deficiencies of the above prior art. SUMMARY

[0006] In view of the problems existing in the prior art, the present application provides a substrate for protecting a conductive layer while preventing waterlogging and a preparation method thereof.

[0007] The present application is realized in that a preparation method of a substrate for protecting a conductive layer while preventing waterlogging comprises the following steps:

[0008] Step one, select PTFE fibers with moderate density as the substrate; polish high-purity metal Cu particles with sandpaper to remove surface dirt;

[0009] Step two, place the polished metal particles into the corresponding evaporation source of the vacuum chamber for thermal evaporation and fix them, and place the selected PTFE above the evaporation source for vacuum evaporation;

[0010] Step three, first vacuum thermal evaporation film: deposit a first layer of metal thin film on the surface of the PTFE fiber using thermal evaporation technology;

[0011] Step four, after the first metal film is plated, evenly spray the carbon black solution onto the surface of the plated PTFE to form a uniform intermediate layer;

[0012] Step five, second vacuum thermal evaporation film: second metal film plating on the carbon black layer to form a composite film structure.

[0013] Further, during the first vacuum thermal evaporation film plating, the crystal oscillator of the thermal evaporation equipment is used to monitor the film thickness in real time to ensure that the thickness of the metal thin film is accurately 250 nm;

[0014] In the vacuum chamber, as the current heats the evaporation source, the Cu particles gradually gasify into metal particles; the metal particles fly upward in the high-vacuum environment and are uniformly deposited on the surface of the PTFE.

[0015] Further, during the second vacuum thermal evaporation film plating, the Cu particles gasified on the surface of the carbon black form a second layer of metal thin film with a thickness of 250 nm.

[0016] Further, the first vacuum thermal evaporation and the second vacuum thermal evaporation: the evaporation rate is set to 3 Å / s, the current range is 100-140 A, and the vacuum chamber pressure is kept at 5×10 -5 to 9×10 -5 Pa.

[0017] Further, the substrate temperature is controlled in the range of 25-60℃ to ensure that the metal particles coagulate to form a dense film.

[0018] Further, the carbon black solution is prepared: 4 mg of Ketjen black, 0.4 mL of ethanol and 50 μL of nafion are mixed to form a uniform carbon black solution.

[0019] Another object of the present application is to provide a substrate with a protected conductive layer and water flooding prevention prepared by the method.

[0020] In combination with the above technical solutions and the technical problems solved, the technical solution to be protected by the present application has the following advantages and positive effects:

[0021] The present application selects commercial PTFE with obvious fibrous structure, uses vacuum thermal evaporation method to plate copper source or other metals on the selected PTFE, then sprays a thin layer of prepared carbon black solution on the PTFE with plated metal, and then uses vacuum evaporation method to plate a layer of copper or required metal. The present application has a protective layer to protect the conductive layer and maintain the smoothness of the circuit, and can also prevent water flooding and ensure the smoothness of the gas channel, thereby improving the stability of the catalytic reaction. The intermediate carbon black not only protects the inner conductive layer from being damaged, but also effectively prevents the electrode from being flooded. The present application can also be applied to other catalytic reactions. The significant technical progress includes:

[0022] (1) Improve catalytic efficiency: the composite structure significantly improves the catalytic activity and stability of the metal film.

[0023] (2) Improve material adaptability: by changing the metal source, it can be widely used in fuel cells, water treatment and other catalytic fields.

[0024] (3) Reduce cost: the method can use low-cost metal materials and realize batch production, with significant economic advantages. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the flow chart of the method for preparing a substrate with a protected conductive layer and water flooding prevention provided by the embodiment of the present application.

[0026] Figure 2This is a comparison diagram of CO2RR stability between Cu-C substrate and Cu-C-Cu substrate provided in the embodiments of the present invention.

[0027] Figure 3 The diagram shows the product distribution of Cu-C substrate and Cu-C-Cu substrate provided in the embodiments of the present invention under 3M KCl (pH=1), (a) Cu-Cu substrate, (b) Cu-C-Cu substrate.

[0028] Figure 4 The 600mAcm provided in this embodiment of the invention -2 A comparison of electrolyte permeation and voltage decay during CO2RR.

[0029] Figure 5 The 600mAcm provided in this embodiment of the invention -2 Schematic diagrams of cracks on the electrode surface before and after the water immersion experiment: (a) Schematic diagram of cracks on the Cu-Cu substrate; (b) Schematic diagram of cracks on the Cu-C-Cu substrate. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] In the current field of functional thin film fabrication, conductive layers are often directly exposed to the external environment. Especially under humid or liquid immersion conditions, the metal layer is prone to oxidation, corrosion, or even detachment due to moisture penetration or liquid contact, leading to decreased conductivity or failure. To address this common problem in industrial applications, traditional methods often rely on a single waterproof coating covering the conductive layer. However, such coatings typically introduce high interfacial resistance, affecting overall conductivity, and are prone to cracking under repeated bending or mechanical stress, reducing protective effectiveness. Therefore, achieving stable waterproof and immersion-proof functionality without sacrificing conductivity has always been a core technical challenge that urgently needs to be solved in this field.

[0032] This method constructs a bimetallic layer-carbon black interlayer composite structure on a hydrophobic PTFE fiber matrix, achieving a synergistic balance between protection and conductivity through multi-level interface design. The first metal film is directly deposited on the PTFE fiber surface via vacuum thermal evaporation, forming a uniform and dense conductive layer to ensure initial conductivity and adhesion. The introduction of the carbon black interlayer not only provides microporous adsorption and interfacial buffering but also offers additional conductive pathways, reducing electron transport resistance caused by the waterproof structure. The second metal film is deposited on the carbon black layer, sealing the micropores and forming a barrier to further block water molecule penetration, thereby significantly improving waterproof immersion stability.

[0033] In terms of process mechanism, vacuum thermal evaporation utilizes a high-vacuum environment to reduce the mean free path resistance of metal vapor, allowing metal particles to deposit on the substrate surface in a nearly straight line. By controlling the evaporation rate and substrate temperature, the density and crystallinity of the thin film can be effectively adjusted to improve corrosion resistance. During the first coating, metal particles directly adhere to the PTFE surface and partially embed, forming a firm interface. The intermediate layer formed by carbon black spraying exhibits a highly dispersed state, with a conductive network formed between carbon black particles, providing a rough interface for subsequent metal deposition and increasing mechanical interlocking and metal bonding strength.

[0034] The second coating process deposits a metal thin film on the surface of the carbon black layer. Due to the porous and high specific surface area characteristics of carbon black particles, metal vapor can fill and coat the surface of carbon black particles, forming a continuous and dense outer metal barrier. This composite interface effectively blocks the diffusion path of moisture and oxygen, significantly delaying the oxidation process of the metal. In addition, the carbon black structure between the two metal layers can disperse stress and slow down crack propagation when subjected to external mechanical impact or bending deformation, ensuring long-term stability of the conductive and waterproof properties.

[0035] In industrial applications, this method is suitable for flexible electronic devices, wearable sensors, conductive fabrics, and underwater electronic equipment, and can maintain stable conductivity and structural integrity in frequent bending and long-term wet environments. Compared with single-layer waterproof coating processes, this method provides better water vapor shielding ability and mechanical fatigue resistance while ensuring low interfacial resistance, significantly extending the service life of products and reducing maintenance costs.

[0036] In summary, this technology solves the technical bottleneck of the conductive layer being easily damaged in wet and submerged environments through the coupling optimization of material interface structure design and vacuum coating process, achieving a balance between protection performance and conductivity, and providing a scalable and high-reliability protection substrate preparation scheme for related industries. This scheme has high engineering potential in terms of process controllability, material compatibility, and performance stability. As shown in FIG. 1, the embodiment of the present application provides a preparation method of a substrate for protecting a conductive layer while preventing water immersion, including the following steps: Figure 1

[0037] Step one, select PTFE fibers with moderate density as the substrate; use sandpaper to polish high-purity metal Cu particles to remove surface dirt;

[0038] Step two, place the polished metal particles into the corresponding evaporation source of the vacuum chamber for thermal evaporation and fix them, and place the selected PTFE above the evaporation source for vacuum evaporation;

[0039] ​Step three, first vacuum thermal evaporation coating: Using thermal evaporation technology to deposit the first layer of metal film on the surface of PTFE fiber;

[0040] Step four, after the first metal coating is completed, evenly spray the carbon black solution on the surface of the coated PTFE to form a uniform intermediate layer;

[0041] Step five, second vacuum thermal evaporation coating: The second metal coating is carried out on the carbon black layer to form a composite film structure.

[0042] (1) Selection and preparation of PTFE fiber substrate

[0043] PTFE (Polytetrafluoroethylene) is a kind of high polymer material with obvious fiber structure, its special chemical inertness and excellent thermal stability make it become the ideal substrate.

[0044] Selection requirements: The selected PTFE fiber should have moderate density to ensure uniform deposition of particles during metal coating process and form stable metal film layer.

[0045] Pre-treatment process: PTFE fiber needs to be pasted above the evaporation source of thermal evaporation equipment to ensure that metal particles can accurately fly and condense on the surface of PTFE during evaporation process.

[0046] (2) Preparation of metal Cu particles

[0047] In order to obtain high-purity metal film layer, metal Cu particles need to be carefully treated:

[0048] Surface cleaning: Use sandpaper to polish metal Cu particles to remove surface dirt and reduce impurity interference during coating process.

[0049] Evaporation source fixation: Fix the treated Cu particles on the evaporation source in the vacuum evaporation equipment to ensure the stability of evaporation process and uniform release of metal particles.

[0050] (3) First vacuum thermal evaporation coating

[0051] Using thermal evaporation technology to deposit the first layer of metal film on the surface of PTFE fiber:

[0052] Evaporation principle: In the vacuum chamber, as the evaporation source is heated by electric current, Cu particles gradually gasify into metal particles. Metal particles fly upward in high vacuum environment and uniformly deposit on the surface of PTFE.

[0053] Coating Control: Real-time monitoring of film thickness by crystal oscillator piece of thermal evaporation equipment, to ensure the thickness of the metal film is accurate to 250 nm. The evaporation rate of this process is set to 3 Å / s, the current range is 100-140 A, the vacuum chamber pressure is maintained at 5×10 -5 to 9×10 -5 Pa.

[0054] Environmental Conditions: The substrate temperature is controlled within the range of 25-60 ℃ to ensure that metal particles coagulate to form a dense film.

[0055] (4) Preparation and Spraying of Carbon Black Solution

[0056] After the first metal coating is completed, further spray carbon black solution on the PTFE surface to improve the catalytic performance:

[0057] Solution Preparation: Mix 4 mg of carbon black, 0.4 mL of ethanol and 50 μL of nafion to make a uniform carbon black solution. The nanostructure of carbon black has porous and hydrophobic characteristics, which is conducive to the construction of gas transmission channels, preventing waterlogging and helping to improve the efficiency of catalytic reactions. (Carbon black does not have catalytic ability)

[0058] Spraying Technology: Use uniform spraying equipment to cover the carbon black solution on the surface of the coated PTFE, forming a uniform intermediate layer, further enhancing the adhesion and waterproof performance of the subsequent metal coating.

[0059] (5) Second Vacuum Thermal Evaporation Coating

[0060] Second metal coating on the carbon black layer to form a composite film structure:

[0061] Coating Steps: Repeat the process of the first evaporation, gasify Cu particles and deposit them on the surface of the carbon black, forming a second layer of metal film with a thickness of 250 nm.

[0062] Coating Characteristics: The composite structure of double-layer metal film and carbon black intermediate layer provides higher conductivity and stability, making it more active in catalytic reactions.

[0063] (6) Application Expansion and Optimization

[0064] This method has good adaptability and can be applied to different catalytic reaction scenarios:

[0065] Metal Source Variability: By replacing the metal evaporation source (such as Pt, Ni, Ag, etc.), different types of metal films can be deposited on the surface of PTFE, adapting to various catalytic reaction needs.

[0066] Application scenarios: The composite structure can be widely used in energy conversion, electrochemical catalysis, gas adsorption and separation, etc., and has the advantages of low cost and high efficiency.

[0067] Through the above steps, the composite coating method of the application realizes the precise combination of the metal thin film and the carbon black layer, forms a multilayer film structure with excellent catalytic performance and stability, and exhibits significant industrial application potential.

[0068] Example 1:

[0069] A specific method for preparing a substrate for protecting a conductive layer and preventing water flooding:

[0070] (1) Purchase PTFE with obvious fibrous structure, and the selected PTFE fibers should not be too dense, but also not too sparse;

[0071] (2) According to the thickness of the film to be plated, grind the appropriate amount of metal Cu particles with sandpaper to remove surface dirt;

[0072] (3) Put the ground metal particles into the corresponding evaporation source of the thermal evaporation vacuum chamber and fix them, and place the selected PTFE above the evaporation source, and perform vacuum evaporation. The metal source is gasified into metal particles, which fly to the surface of the substrate material and condense to form a metal thin film layer;

[0073] (4) Add carbon black, ethanol and nafion to prepare a carbon black solution in a test tube;

[0074] (5) Spray the carbon black solution on the PTFE with metal evaporation;

[0075] (6) According to the thickness of the film to be plated, grind the appropriate amount of metal Cu particles with sandpaper to remove surface dirt;

[0076] (7) Put the ground metal particles into the corresponding evaporation source of the thermal evaporation vacuum chamber and fix them, and place the PTFE sprayed with carbon black above the evaporation source, and perform vacuum evaporation. The metal source is gasified into metal particles, which fly to the surface of the substrate material and condense to form a metal thin film layer.

[0077] The vacuum evaporation conditions are:

[0078] (1) The evaporation rate is 3 Å / s.

[0079] (2) The thermal evaporation current is 100-140 A.

[0080] (3) The pressure in the thermal evaporation vacuum chamber is 5×10 -5 ~9×10 -5 Pa.

[0081] (4) The thickness of the twice thermal evaporation coating is 250 nm, which is controlled by the crystal oscillator plate in the thermal evaporation instrument.

[0082] (5) The thermal evaporation substrate temperature is 25-60 ℃.

[0083] (6) Three copper sources are placed in the corresponding evaporation sources in the thermal evaporation vacuum chamber and fixed.

[0084] (7) The carbon black formula is 4 mg Ketjen black, 0.4 mL ethanol, and 50 μL nafion.

[0085] It can be extended to other catalytic reactions, and different films can be plated by changing the type of metal source as needed for different catalytic reactions.

[0086] Example 2: Preparation of a fuel cell catalytic electrode

[0087] Background and needs

[0088] Fuel cells require efficient catalytic electrodes in energy conversion, and the conductivity and catalytic activity of electrode materials directly determine the performance of the battery. In this embodiment, the composite coating method of the application is used to prepare electrode materials to improve the catalytic performance and stability of the fuel cell catalytic electrode.

[0089] Specific steps

[0090] 1. Select the substrate

[0091] Select PTFE with obvious fibrous shape as the substrate, and cut it into the required size for the fuel cell electrode after cleaning.

[0092] The PTFE material has a smooth surface and is corrosion resistant, making it suitable as a catalytic electrode substrate.

[0093] 2. First metal coating

[0094] Use high-purity Cu particles and carefully polish them with sandpaper to ensure a clean surface.

[0095] Perform the first coating in a thermal evaporation vacuum chamber, control the evaporation rate at 3 Å / s, and maintain the vacuum chamber pressure at , and the coating thickness reaches 250 nm.

[0096] 3. Carbon black coating treatment

[0097] Prepare a carbon black solution (4 mg Ketjen black, 0.4 mL ethanol, and 50 μL nafion) and evenly cover the metal coating layer using a spraying technique.

[0098] Place the sprayed material in a well-ventilated environment to dry, ensuring uniform adhesion of the carbon black layer.

[0099] 4. Second metal plating

[0100] Repeat the metal evaporation step to deposit a second layer of metal film on the surface of the carbon black layer, with a thickness of 250 nm.

[0101] Complete the preparation of the composite film, forming a sandwich structure of metal-carbon black-metal.

[0102] 5. Electrode performance test

[0103] Apply the prepared material to a fuel cell to test its conductivity, catalytic activity, and stability.

[0104] The test results show that the electrode exhibits excellent oxygen reduction reaction catalytic ability in the fuel cell reaction, with a catalytic efficiency increase of about 30% and a service life of more than 5000 hours.

[0105] Example 3: Preparation of a catalyst for water treatment

[0106] Background and needs

[0107] In industrial wastewater treatment, high-efficiency catalysts are crucial for removing organic pollutants. This example uses the method of the present invention to prepare a catalyst for photocatalytic degradation of organic matter in water.

[0108] Specific steps

[0109] 1. Select the substrate

[0110] Select a loose PTFE material as the substrate, cut it into small pieces with a diameter of 10 cm, and use it as a support for the photocatalyst.

[0111] 2. First metal plating

[0112] Use high-purity Ti particles instead of Cu particles, polish them, and place them in the evaporation source of the thermal evaporation equipment.

[0113] Evaporate in a vacuum chamber with an evaporation rate of 3 A / s and a vacuum chamber pressure of , controlling the film thickness to be 250 nm.

[0114] 3. Carbon black coating treatment

[0115] Prepare a carbon black solution (4 mg of Ketjen black, 0.4 mL of ethanol, and 50 μL of nafion) and spray it onto the surface of the metal film layer to form a uniform adsorption layer.

[0116] After drying treatment, the carbon black layer effectively enhances the catalytic activity of the metal film.

[0117] 4. Second metal plating

[0118] Another layer of Ti film was evaporated on the surface of the carbon black layer to form a metal-carbon black-metal composite structure, and the film layer thickness was controlled to be 250 nm.

[0119] 5. Catalyst performance test

[0120] The prepared catalyst was placed in simulated wastewater, and the degradation efficiency of organic pollutants such as methyl orange was tested by ultraviolet light irradiation.

[0121] The test results show that the catalyst can degrade 90% of methyl orange in 20 minutes, the catalytic efficiency is increased by about 50% compared with the traditional single-layer film catalyst, and the service life exceeds 100 cycles of experiments.

[0122] As shown in Figure 2 , the cathode solution is 3M kcl solution with PH=1, the anode solution is 0.5MH2SO4, and the current density is 600mA cm -2 , the stability of CO2RR (electrocatalytic reduction of carbon dioxide) is improved: for the substrate without interlayer (Cu-Cu), the stability is only 5h when the C2+ faradic efficiency is 69%; for the substrate with interlayer (Cu-C-Cu), the stability is extended to 45h when the C2+ faradic efficiency is 70%.

[0123] As shown in Figure 3 , the Flow cell was used to perform the electrocatalytic CO2RR staircase current test on the Cu-Cu substrate and the Cu-C-Cu substrate respectively. Figures a-b show the product distribution of the Cu-Cu substrate and the Cu-C-Cu substrate when the pH value of the 3M KCl solution is 1. The FE C2+ of the Cu-C-Cu substrate is higher than that of the Cu-Cu substrate in a wide range of current density (200 mA cm -2 to 1200 mA cm -2 ). With the increase of current density, especially at high current density (600 mA cm -2 to 1200 mA cm -2 ), the FE H2 of the Cu-Cu substrate rises significantly faster than that of the Cu-C-Cu substrate (hydrogen production is an unwanted competing reaction). These results show that the Cu-C-Cu substrate outperforms the Cu-Cu substrate in a very wide range of current density, especially at high current density.

[0124] As shown in Figure 4 , the current density is 600 mA cm 2Carbon dioxide electroreduction was tested using a flow cell at a current density of [insert current density here]. The figures clearly show that for the control Cu-Cu substrate, no electrolyte seepage occurred after 1 h of reaction. Liquid gradually seeped through the electrode into the gas chamber after 3 h, and the liquid level in the gas chamber increased further after 4 h. After 5 h, not only was a large amount of liquid seeped out, but some salt was also deposited, indicating severe water flooding of the electrode. For the Cu-P-Cu substrate, no liquid appeared in the gas chamber after 5 h of reaction, indicating that even at 600 mA cm⁻¹, the protective layer [insert current density here]. 2 It can also effectively prevent flooding even under high current density.

[0125] It is believed that flooding will inevitably damage the internal structure of the electrodes. At 600 mA cm⁻¹ 2 The voltage change over time during the reaction under constant current strongly supports this viewpoint of the invention. As shown in Figures (c and d), the voltage remained relatively stable for the first 15,000 seconds of the reaction. However, after 15,000 seconds, the voltage on the Cu-Cu substrate began to gradually decrease, experiencing a sharp drop at 30,000 seconds; while the voltage on the Cu-P-Cu substrate remained stable throughout. This indicates that the conductivity of the Cu-Cu substrate was compromised, while the conductivity of the Cu-P-Cu substrate remained intact.

[0126] like Figure 5 As shown, flooding damages the electrode structure. This invention also compared the changes in the electrode surface before and after a 600 mA cm² flooding experiment. The figure shows that after the same reaction time, a network of cracks appeared on the Cu-Cu substrate, while no cracks appeared on the Cu-C-Cu substrate. This confirms that, as this invention hypothesized, flooding indeed damages the electrode structure, thereby reducing its conductivity. The protective layer introduced in this invention effectively protects the electrode and prevents structural damage.

[0127] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a substrate that protects a conductive layer while preventing flooding, characterized in that, Includes the following steps: Step 1: Select PTFE fiber as the substrate and polish the surface of the Cu metal particles. Step 2: Place the polished Cu particles at the evaporation source position of the vacuum thermal evaporation device, and place the PTFE substrate above the evaporation source; Step 3: Deposit the first metal film on the PTFE surface using thermal evaporation technology; Step 4: Spray carbon black solution onto the surface of the first metal film to form an intermediate layer; Step 5: A second metal film is deposited on the intermediate layer using thermal evaporation technology to form a composite film substrate with waterproof and conductive properties.

2. The method as described in claim 1, characterized in that, The thickness of the first metal film is 250 nm, and the film thickness is monitored in real time by a crystal oscillator to ensure accurate deposition.

3. The method as described in claim 1, characterized in that, The second metal film has a thickness of 250 nm and is deposited on the surface of the carbon black layer to form a double-layer metal film structure.

4. The method as described in claim 1, characterized in that, During the deposition of the first and second metal thin films, the evaporation rate was 3 Å / s, the current range was 100-140 A, and the vacuum chamber pressure was 5×10^-5 to 9×10^-5 Pa.

5. The method as described in claim 3, characterized in that, During the deposition of the second metal thin film, the substrate temperature is controlled between 25 and 60°C to promote the aggregation of metal particles to form a dense thin film.

6. A method for preparing a carbon black intermediate layer, characterized in that, Includes the following steps: Mix 4 mg of carbon black, 0.4 mL of ethanol, and 50 μL of nafion; A stable carbon black solution is obtained by uniformly dispersing the mixture through ultrasound or stirring.

7. The method for preparing the carbon black intermediate layer as described in claim 6, characterized in that, The carbon black is Ketjen black, and its particle size is controlled in the range of 20 to 60 nm.

8. A substrate with a protective conductive layer and waterproofing properties prepared by any one of claims 1 to 7, characterized in that, The substrate includes: PTFE fiber substrate; The first Cu metal film with a thickness of 250 nm is applied to the surface of the substrate. A carbon black intermediate layer disposed on the first metal film; A second Cu metal film with a thickness of 250 nm is deposited on the carbon black intermediate layer.

9. The substrate as claimed in claim 8, characterized in that, The substrate has an overall structure in the form of a composite thin film layer, which combines conductivity and water resistance.

10. An electronic device, characterized in that, The substrate, including the protective conductive layer as described in claim 8 or 9, is waterproof and flood-proof, for functional components that require a combination of waterproofing and conductivity.

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