Preparation method of electrode foil

Abstract

The invention discloses a preparation method of an electrode foil. The preparation method comprises three steps of surface pretreatment, construction of a middle enhancement layer and functional modification of an outer layer. In the surface pretreatment, deionized water and ethanol ultrasonic cleaning are combined with vacuum drying; the middle reinforcing layer is formed by dipping and sintering mixed slurry of aluminum powder, silica sol and a stearic acid dispersing agent; and the outer layer is constructed through dip-coating and thermocuring of epoxy resin and a silicon dioxide micro powder solution. According to the preparation method of the electrode foil, through the synergistic effect of surface pretreatment, middle enhancement layer construction and outer layer functional modification, the conductivity, mechanical strength and corrosion resistance of the electrode foil are improved, meanwhile, the preparation process is simplified, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of electrode material technology, specifically to a method for preparing an electrode foil. Background Technology

[0002] Traditional electrode foil fabrication methods typically rely on a single coating or simple processing, resulting in limitations in conductivity, mechanical strength, and corrosion resistance. For example, electrode foils formed solely through the sintering of aluminum powder in existing technologies suffer from insufficient conductivity and interfacial bonding, leading to performance degradation at high current densities. Furthermore, traditional processes lack optimized design for surface pretreatment and multilayer structures, making it difficult to meet the high-performance and high-stability requirements of modern electronic devices for electrode foils.

[0003] This invention introduces a design that sequentially constructs an intermediate conductive enhancement layer and an outer functionalized modification layer on the surface of a basic electrode foil, significantly improving the overall performance of the electrode foil and overcoming the shortcomings of existing technologies. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing electrode foil, which improves the conductivity, mechanical strength and corrosion resistance of electrode foil through the synergistic effect of surface pretreatment, intermediate reinforcement layer construction and outer layer functionalization modification, while simplifying the preparation process and reducing production costs.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The technical solution provided by this invention is: a method for preparing electrode foil, comprising the following steps: A method for preparing an electrode foil includes the following steps: S1: Surface pretreatment: The base electrode foil is ultrasonically cleaned with deionized water and ethanol in sequence for 8-12 minutes to remove surface impurities, and then dried in a vacuum of 0.04-0.06MPa and a temperature of 65-75℃ for 12-18 minutes. S2: Construction of intermediate reinforcement layer: Prepare a mixed slurry containing aluminum powder and silica sol, wherein the aluminum powder has an average particle size of 5-15μm and the silica sol has a solid content of 20%-30%. Immerse the base electrode foil in the mixed slurry, wherein the mass fraction of aluminum powder in the slurry is 10%-15% and the mass fraction of silica sol is 8%-12%. After immersion for 4-6 minutes, remove the foil and pre-dry it at 80-100℃ for 15-25 minutes. Then place it under a nitrogen protective atmosphere and sinter at 450-550℃ for 25-35 minutes to form an intermediate conductive reinforcement layer. S3: Outer layer functionalization modification: The electrode foil constructed through the intermediate layer is immersed in a solution containing epoxy resin and silica micro powder, and a uniform coating is formed on its surface by dip coating. The mass fraction of epoxy resin in the solution is 12%-18%, the mass fraction of silica micro powder is 3%-5%, the dip coating speed is 5-15cm / min, and then it is thermocured at 140-160℃ for 40-50 minutes to construct the outer layer structure.

[0006] Furthermore, in the surface pretreatment step, the volume concentration of ethanol is 90%-95%.

[0007] Furthermore, in the intermediate reinforcement layer construction step, 0.5%-1.5% by mass of stearic acid is added to the mixed slurry as a dispersant.

[0008] Furthermore, in the outer layer functionalization modification step, the average particle size of the silica micropowder is 1-3 μm.

[0009] Furthermore, in the outer functional modification step, the thermosetting adopts a stepped heating method: first, it is kept at 100-120℃ for 20 minutes, and then the temperature is increased to 140-160℃ for curing for 20-30 minutes.

[0010] An electrode foil is prepared by the above-described method.

[0011] The beneficial effects of this technical solution are: (1) The aluminum powder and silica sol in the intermediate reinforcement layer form a conductive network, which significantly reduces the interface resistance and improves the conductivity of the electrode foil.

[0012] (2) The addition of silica sol enhances the mechanical strength of the intermediate layer, while the outer epoxy resin coating further improves the stability of the overall structure.

[0013] (3) The addition of silica micro powder improves the corrosion resistance of the outer coating and extends the service life of the electrode foil. Attached Figure Description

[0014] Figure 1 This is a flowchart of a method for preparing an electrode foil according to the present invention; Figure 2 This is a comparison table of the compositional differences in the electrode foil preparation method proposed in this invention; Figure 3 This is a data comparison table for a method of preparing an electrode foil proposed in this invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] The specific implementation process is as follows: Example 1: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: The base electrode foil is ultrasonically cleaned with deionized water for 10 minutes, and then ultrasonically cleaned with 95% ethanol for 10 minutes to remove surface impurities; then it is dried in a vacuum of 0.05 MPa and a temperature of 70°C for 15 minutes. S2: Construction of the intermediate reinforcing layer: A mixed slurry was prepared with the following components in the following proportions: 10% aluminum powder (average particle size 10μm), 8% silica sol (solid content 25%), 0.5% stearic acid (dispersant), and 81.5% ethanol. The base electrode foil was immersed in the slurry for 5 minutes, then removed and pre-dried at 90°C for 20 minutes. It was then placed under a nitrogen protective atmosphere and sintered at 500°C for 30 minutes to form the intermediate conductive reinforcing layer.

[0017] S3: External functionalization modification: A solution was prepared with the following components in the following proportions: epoxy resin 15%, silica micropowder (average particle size 2μm) 4%, and ethanol 81%. A uniform coating was formed on the electrode foil surface by dip coating at a pulling speed of 10cm / min, followed by thermosetting at 150℃ for 45 minutes to construct the outer layer structure. The epoxy resin was a bisphenol A type epoxy resin, specifically E-44 type epoxy resin.

[0018] Performance testing Conductivity: The resistivity was 0.02 Ω·cm, as measured by the four-probe method. Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 48 hours); This embodiment achieves better overall performance by optimizing surface pretreatment parameters and the proportion of intermediate layer components; the synergistic effect of aluminum powder and silica sol effectively improves conductivity, the dispersing effect of stearic acid ensures the uniformity of the slurry, and the combination of outer epoxy resin and silica micropowder significantly improves corrosion resistance.

[0019] Example 2: Please see Figure 1-3The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: The base electrode foil is ultrasonically cleaned with deionized water for 8 minutes, and then ultrasonically cleaned with 90% ethanol for 8 minutes to remove surface impurities; then it is dried in a vacuum of 0.04 MPa and a temperature of 65°C for 12 minutes. S2: Construction of intermediate reinforcement layer: Prepare a mixed slurry with the following components in proportion: aluminum powder (5μm) 12%, silica sol (20%) 10%, stearic acid 1.0%, ethanol 77%; immerse the base electrode foil in the slurry for 4 minutes, remove it, pre-dry it at 80°C for 15 minutes, and then place it under a nitrogen protective atmosphere and sinter at 450°C for 25 minutes to form an intermediate conductive reinforcement layer; S3: Outer layer functionalization modification: Prepare a solution with the following components in proportion: epoxy resin 12%, silicon dioxide (1μm) 3%, ethanol 85%; form a uniform coating on the electrode foil surface by dip coating at a pulling speed of 5cm / min, and then heat cure at 140℃ for 40 minutes to construct the outer layer structure. Performance testing Electrical conductivity: resistivity is 0.025 Ω·cm; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 1, with slight local peeling; Corrosion resistance: A small number of corrosion spots appeared on the surface after salt spray test (5% NaCl solution, 35℃, 24 hours); In this embodiment, the aluminum powder particle size is small and the silica sol solid content is low, resulting in the conductivity of the intermediate layer being slightly lower than that in Example 1. In addition, the epoxy resin content of the outer layer is low, which may affect the corrosion resistance of the coating. The adhesion test results show that the ethanol concentration and ultrasonic time of the surface pretreatment have a certain impact on the coating adhesion.

[0020] Example 3: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: The base electrode foil was ultrasonically cleaned with deionized water for 12 minutes, and then ultrasonically cleaned with 92.5% ethanol for 12 minutes to remove surface impurities; then dried in a vacuum of 0.06 MPa and a temperature of 75°C for 18 minutes. S2: Construction of intermediate reinforcement layer: The proportions of each component in the mixed slurry are as follows: aluminum powder (15μm) 15%, silica sol (30%) 12%, stearic acid 1.5%, ethanol 71.5%; The base electrode foil is immersed in the slurry for 6 minutes and then removed. It is pre-dried at 100°C for 25 minutes and then placed under a nitrogen protective atmosphere and sintered at 550°C for 35 minutes to form an intermediate conductive reinforcement layer; S3: Outer layer functionalization modification: Prepare a solution with the following components in proportion: epoxy resin 18%, silicon dioxide (3μm) 5%, ethanol 77%; form a uniform coating on the electrode foil surface by dip coating at a pulling speed of 15cm / min, and then heat cure at 160℃ for 50 minutes to construct the outer layer structure. Performance testing Electrical conductivity: resistivity is 0.018 Ω·cm; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 72 hours); This embodiment further enhances the conductivity of the intermediate layer by increasing the content of aluminum powder and silica sol; the higher silica sol solid content and aluminum powder particle size help to form a denser conductive network; the high content combination of epoxy resin and silica micro powder in the outer layer significantly improves corrosion resistance, while the optimization of thermosetting temperature and time enhances the stability of the coating.

[0021] Example 4: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: Same as in Example 1; S2: Construction of intermediate reinforcement layer: Prepare a mixed slurry with the following components in proportion: aluminum powder (10μm) 10%, silica sol (25%) 8%, stearic acid 1.0%, ethanol 81%; immerse the base electrode foil in the slurry for 5 minutes, remove it, pre-dry it at 90°C for 20 minutes, and then place it under a nitrogen protective atmosphere and sinter at 500°C for 30 minutes to form an intermediate conductive reinforcement layer; S3: Outer layer functionalization modification: Same as in Example 1; Performance testing Electrical conductivity: resistivity is 0.02 Ω·cm, comparable to Example 1; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 48 hours); This embodiment further optimizes the dispersibility of the slurry by increasing the content of the dispersant stearic acid, ensuring the uniformity of the intermediate layer. Performance test results show that the increase in dispersant content has no significant effect on conductivity and adhesion, but may improve the stability of the slurry to some extent.

[0022] Example 5: Please see Figure 1-3The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: The base electrode foil is ultrasonically cleaned with deionized water for 10 minutes, and then ultrasonically cleaned with 95% ethanol for 10 minutes to remove surface impurities; then it is dried in a vacuum of 0.05 MPa and a temperature of 70°C for 15 minutes. S2: Construction of intermediate reinforcement layer: Prepare a mixed slurry with the following components in proportion: aluminum powder (8μm) 11%, silica sol (22%) 9%, stearic acid 0.8%, and ethanol 79.2%; after immersing the base electrode foil in the slurry for 5 minutes, remove it and pre-dry it at 95°C for 22 minutes, then place it under a nitrogen protective atmosphere and sinter at 520°C for 32 minutes to form an intermediate conductive reinforcement layer; S3: External functionalization modification: Prepare a solution with the following components in proportion: epoxy resin 14%, silicon dioxide (2μm) 3.5%, ethanol 82.5%; form a uniform coating on the electrode foil surface by dip coating at a pulling speed of 12cm / min, and then heat cure at 150℃ for 45 minutes to construct the outer layer structure. Performance testing Conductivity: The resistivity is 0.019 Ω·cm, which is 35% lower than that of traditional electrode foil; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 60 hours); This embodiment balances conductivity and mechanical strength by adjusting the aluminum powder particle size and silica sol solid content; the higher silica sol solid content enhances the structural stability of the intermediate layer, and the combination of epoxy resin and silica micropowder in the outer layer with a moderate content reduces cost while ensuring corrosion resistance.

[0023] Example 6: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: The base electrode foil was ultrasonically cleaned with deionized water for 9 minutes, and then ultrasonically cleaned with 93% ethanol for 9 minutes to remove surface impurities; then dried in a vacuum of 0.05 MPa and a temperature of 72°C for 16 minutes. S2: Construction of intermediate reinforcement layer: Prepare a mixed slurry with the following components in proportion: aluminum powder (12μm) 13%, silica sol (28%) 11%, stearic acid 1.2%, and ethanol 74.8%; after immersing the base electrode foil in the slurry for 5 minutes, remove it and pre-dry it at 85°C for 18 minutes, then place it under a nitrogen protective atmosphere and sinter it at 480°C for 28 minutes to form an intermediate conductive reinforcement layer; S3: Outer layer functionalization modification: Prepare a solution with the following components in proportion: epoxy resin 16%, silicon dioxide (2.5μm) 4.5%, ethanol 79.5%; form a uniform coating on the electrode foil surface by dip coating at a pulling speed of 8cm / min, and then heat cure at 150℃ for 42 minutes to construct the outer layer structure. Performance testing Conductivity: The resistivity is 0.021 Ω·cm, which is 28% lower than that of traditional electrode foil; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 50 hours); This embodiment uses aluminum powder with medium particle size and silica sol with medium solid content to achieve a balance between conductivity and process stability; the combination of epoxy resin and silica micropowder with medium content in the outer layer reduces material costs while ensuring performance.

[0024] Example 7: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: The base electrode foil was ultrasonically cleaned with deionized water for 11 minutes, and then ultrasonically cleaned with 94% ethanol for 11 minutes to remove surface impurities; then dried in a vacuum of 0.05 MPa and a temperature of 73°C for 17 minutes. S2: Construction of intermediate reinforcement layer: Prepare a mixed slurry with the following components in proportion: 10% aluminum powder (10μm), 10% silica sol (25%), 0.5% stearic acid, and 79.5% ethanol; Immerse the base electrode foil in the slurry for 5 minutes, remove it, pre-dry it at 98°C for 23 minutes, and then sinter it at 530°C for 33 minutes under a nitrogen protective atmosphere to form an intermediate conductive reinforcement layer; S3: Outer layer functionalization modification: Same as in Example 1; Performance testing Electrical conductivity: resistivity is 0.017 Ω·cm; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 72 hours); This embodiment further enhances the conductivity and mechanical strength of the intermediate layer by increasing the particle size of aluminum powder and the solid content of silica sol; the combination of high epoxy resin and silica micro powder in the outer layer significantly improves corrosion resistance, making it suitable for demanding industrial applications.

[0025] Example 8: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: Same as in Example 1; S2: Construction of intermediate reinforcement layer: Same as in Example 1; S3: Outer functionalization modification: Prepare a solution with the following components in proportion: epoxy resin 15%, silicon dioxide (2μm) 3%, ethanol 82%; form a uniform coating on the electrode foil surface by dip coating at a pulling speed of 10cm / min, and then heat cure at 160℃ for 50 minutes to construct the outer layer structure. Performance testing Conductivity: The resistivity is 0.019 Ω·cm, which is 35% lower than that of traditional electrode foil; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 60 hours); This embodiment further optimizes the dispersibility of the slurry and the stability of the coating by increasing the content of the dispersant stearic acid and the outer layer thermosetting temperature; performance test results show that the increase in thermosetting temperature has a positive impact on corrosion resistance.

[0026] Example 9: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: Same as in Example 1; S2: Construction of intermediate reinforcement layer: Same as in Example 1; S3: Outer functionalization modification: Prepare a solution with the following components in proportion: epoxy resin 15%, silica (2μm) 5%, ethanol 80%; form a uniform coating on the electrode foil surface by dip coating at a pulling speed of 10cm / min, and then heat cure at 140℃ for 45 minutes to construct the outer layer structure. Performance testing Conductivity: The resistivity is 0.02 Ω·cm, which is 30% lower than that of traditional electrode foil; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 48 hours); This embodiment further optimizes the dispersibility of the slurry and the corrosion resistance of the outer layer by increasing the content of dispersant stearic acid and silica micro powder; performance test results show that the increase in silica micro powder content significantly improves corrosion resistance.

[0027] Example 10: Please see Figure 1-3 The present invention provides a technical solution: a method for preparing an electrode foil, comprising the following steps: S1: Surface pretreatment: Same as in Example 1; S2: Construction of intermediate reinforcement layer: Same as in Example 1; S3: Outer functional modification: Same as in Example 1, thermosetting adopts a stepped method: heat preservation at 110℃ for 20 minutes, then curing at 150℃ for 25 minutes; Performance testing Electrical conductivity: resistivity is 0.02 Ω·cm, comparable to Example 1; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 0, with no peeling. Corrosion resistance: No obvious corrosion marks were found on the surface after salt spray test (5% NaCl solution, 35℃, 48 hours); This embodiment employs a stepped thermosetting process to optimize the performance of the outer layer structure. Performance test results show that stepped curing has no significant impact on adhesion and corrosion resistance, but may improve the uniformity of the coating to some extent.

[0028] Comparative Example 1: Please see Figure 1-3 The present invention provides a comparative solution comprising the following steps: S1: Surface pretreatment: Same as in Example 1; S2: External functionalization modification: The same external solution (15% epoxy resin, 4% silica, 81% ethanol) as in Example 1 is directly coated on the pretreated electrode foil, with the same process parameters as in Example 1; Performance testing Electrical conductivity: The resistivity is 0.05 Ω·cm, which is significantly higher than that of Example 1; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 3, with large areas of peeling off; Corrosion resistance: Obvious corrosion spots appeared on the surface after salt spray test (5% NaCl solution, 35℃, 24 hours); The intermediate reinforcement layer was omitted in this comparative example, which resulted in a significant decrease in the conductivity and adhesion of the electrode foil. The absence of the intermediate layer meant that there was no effective transition layer between the outer coating and the base electrode foil, resulting in insufficient interfacial bonding. At the same time, the reduced conductivity affected the overall performance.

[0029] Comparative Example 2: Please see Figure 1-3 The present invention provides a comparative solution comprising the following steps: S1: Surface pretreatment: Same as in Example 1; S2: Construction of intermediate reinforcement layer: The proportions of each component in the mixed slurry are as follows: aluminum powder 10%, silica sol 8%, oleic acid 0.5%, ethanol 81.5%, and the other parameters are the same as in Example 1; S3: Outer layer functionalization modification: Same as in Example 1; Performance testing Electrical conductivity: The resistivity is 0.03 Ω·cm, which is slightly higher than that of Example 1; Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 1, with slight local peeling; Corrosion resistance: A small number of corrosion spots appeared on the surface after salt spray test (5% NaCl solution, 35℃, 48 hours); In this comparative example, oleic acid was used instead of stearic acid as a dispersant, resulting in slightly poorer dispersibility of the slurry and affecting the uniformity of the intermediate layer, thereby reducing conductivity and adhesion. This indicates that the choice of dispersant has a significant impact on the performance of the intermediate layer, and stearic acid has a better dispersing effect than oleic acid.

[0030] Comparative Example 3: Please see Figure 1-3 The present invention provides a comparative solution comprising the following steps: S1: Surface pretreatment: Soak in deionized water for 10 minutes (without ultrasound), and dry with the same parameters as in Example 1.

[0031] S2: Construction of intermediate reinforcement layer: Same as in Example 1.

[0032] S3: Outer layer functionalization modification: Same as in Example 1.

[0033] Performance testing Electrical conductivity: The resistivity is 0.035 Ω·cm, which is higher than that of Example 1.

[0034] Adhesion: Cross-cut adhesion test showed that the coating adhesion level was 2, with some peeling off.

[0035] Corrosion resistance: Obvious corrosion spots appeared on the surface after salt spray test (5% NaCl solution, 35℃, 24 hours).

[0036] The comparative example did not undergo ultrasonic cleaning, resulting in incomplete removal of impurities from the surface of the base electrode foil, which affected the adhesion between the intermediate and outer coating layers. The decrease in conductivity and adhesion indicates that the surface pretreatment step is crucial to overall performance, and ultrasonic cleaning can effectively improve surface activity and enhance coating adhesion.

[0037] Please see Figure 1-3 : Through systematic analysis of Examples 1-10 and Comparative Examples 1-3, it can be clearly seen that the present invention breaks through the technical limitations of traditional electrode foil single coating or simple treatment, and creatively constructs a three-level system of "surface pretreatment - intermediate reinforcement layer - outer functional modification".

[0038] In the surface pretreatment step, a process of stepwise ultrasonic cleaning with deionized water and ethanol (8-12 minutes) combined with vacuum drying (0.04-0.06 MPa, 65-75℃) was adopted. This process effectively removed impurities such as oil and oxide layer from the surface of the base electrode foil, and avoided damage to the substrate caused by high temperature in traditional cleaning methods. This laid a clean and activated surface foundation for subsequent coating adhesion. In Examples 1-10, the contact angle of the electrode foil surface treated by this step was reduced to below 30°, which significantly improved the wettability with the intermediate layer. In contrast, Comparative Example 3, due to the omission of ultrasonic cleaning, had residual impurities on the surface, and the contact angle was as high as 65°, which directly caused a decrease in coating adhesion (level 2), confirming the necessity of this pretreatment process.

[0039] The intermediate reinforcing layer utilizes a synergistic ratio of aluminum powder (5-15μm) and silica sol (20%-30% solid content) (10%-15% aluminum powder, 8%-12% silica sol), with stearic acid (0.5%-1.5%) introduced as a dispersant. This creates a network structure that combines conductivity and mechanical strength. The aluminum powder acts as a conductive phase, constructing continuous electron transport channels, while the SiO2 framework formed by sintering the silica sol enhances the coating's density and wear resistance. The synergistic effect of these two components solves the problem of electron transfer... In Example 3, the technical challenge of "difficulty in balancing conductivity and mechanical strength" in traditional electrode foils was addressed. When the aluminum powder particle size was 15 μm and the silica sol solid content was 30%, the resistivity was as low as 0.018 Ω·cm, which is 40% lower than that of traditional electrode foils. Furthermore, the coating showed no cracks after 300 bending tests. In contrast, Comparative Example 1, which omitted the intermediate layer, had a resistivity of 0.05 Ω·cm, and the coating peeled off after only 10 bends. This fully demonstrates the crucial role of the intermediate layer in improving conductivity and structural stability.

[0040] The outer functional modification step achieves a balance between corrosion resistance and insulation through a composite design of epoxy resin and silica micropowder (1-3μm) (12%-18% epoxy resin, 3%-5% silica). The continuous film layer formed by the epoxy resin provides a physical barrier, while the filling of silica micropowder reduces coating defects and improves hardness (the pencil hardness of Example 3 reaches 3H, higher than the 2H of the pure epoxy resin coating). The optimization of the pull-up speed (5-15cm / min) in the dip coating process ensures the uniformity of coating thickness, while the stepped thermosetting (pre-curing at 100-120℃ for 20 minutes + curing at 140-160℃ for 20-30 minutes) avoids the internal stress concentration caused by traditional one-time curing, significantly improving the adhesion between the coating and the intermediate layer. After using this process in Example 10, no corrosion was observed in the salt spray test (5% NaCl, 35℃) for 72 hours, while the sample without stepped curing showed rust spots after 48 hours, proving the improved effect of this process.

[0041] From the overall comparison of performance data, in terms of conductivity, the resistivity of Examples 1-10 is all below 0.025 Ω·cm, which is 20%-40% lower than that of traditional electrode foil (0.03-0.04 Ω·cm), with Example 7 being as low as 0.017 Ω·cm. In terms of adhesion, all examples have a cross-cut adhesion rating of 0 or 1, which is far superior to the rating of 3 in Comparative Example 1 and the rating of 2 in Comparative Example 3. In terms of corrosion resistance, the salt spray test tolerance time of the examples generally exceeds 48 hours, with Examples 3 and 7 even reaching 72 hours, while Comparative Examples 1 and 3 showed corrosion within 24 hours. These data fully demonstrate that the present invention achieves a comprehensive improvement in conductivity, mechanical strength, and corrosion resistance through the synergistic design of a three-level structure.

[0042] The testing method is as follows: I. Conductivity Test (Four-Probe Method) Test objective: To determine the resistivity of the electrode foil and evaluate its conductivity; Instrumentation: Four-probe tester (model ST2258A), ambient temperature 25±2℃, relative humidity 45%-55%; Test steps: Cut the electrode foil sample into 50mm×50mm squares and wipe the surface with anhydrous ethanol to remove oil stains; Place the sample flat on the test stage so that the tips of the four probes are in uniform contact with the sample surface (probe spacing 1 mm, applied pressure 50 ± 5 g). Select a test current of 10mA, and record the resistance value after the reading stabilizes. Repeat the test at 5 different locations and take the average value.

[0043] II. Adhesion Test (Cross-cut Test) Test objective: To evaluate the adhesion strength between the coating and the substrate, and between the coatings themselves; Instruments and equipment: crisscross knife (6 blades, 1mm blade spacing), 3M 600 tape (25mm width), magnifying glass (10x magnification); Test steps: Use a cross-cutting tool to make 10×10 grids (1mm×1mm area) perpendicularly across the sample surface. The blade depth should penetrate the coating to the substrate surface. Use a soft-bristled brush to gently sweep along the diagonal of the grid 5 times to remove debris; Apply the tape evenly to the grid area, press it with your fingers to ensure it adheres completely, and after 5 minutes, quickly peel off the tape at a 45° angle. Rating criteria: Grade 0: The mesh edges are completely smooth, with no coating peeling; Level 1: Minor coating peeling occurs at grid intersections, with a peeling area ≤ 5%; Level 2: The coating peels off at the edges or intersections of the grid, with a peeling area of ​​5%-15%; Level 3: Large areas of coating peel off at the edges of the grid or parts of the grid are completely peeled off, with a peeling area of ​​15%-35%; Level 4: Large areas of coating peel off along the edges of the grid or multiple grids are completely peeled off, with a peeling area of ​​35%-65%; Level 5: Large areas of coating peel off, with a peeling area > 65%.

[0044] III. Corrosion Resistance Test (Neutral Salt Spray Test) Test objective: To evaluate the corrosion resistance of electrode foil under salt spray conditions; Instruments and equipment: Salt spray test chamber (model YWX / Q-150), constant temperature and humidity chamber, pH meter with an accuracy of 0.1; Test solution: 5% (mass fraction) sodium chloride solution, adjusted to pH 6.5-7.2 with hydrochloric acid or sodium hydroxide, and filtered through a 0.45μm filter membrane; Test conditions: Salt spray chamber temperature: 35±2℃, relative humidity: >95%; Salt spray deposition rate: 1-2 mL / (h·80cm) 2 ), continuous spraying; The sample should be placed at a 15° angle to the vertical direction, with a spacing of ≥20mm. Test steps: Cut the sample to 100mm x 50mm, seal the edges with anti-corrosion tape, and expose 50cm² of the sample. 2 ; Place the samples in a salt spray chamber for continuous exposure for a specified time (24h, 48h, 72h), remove them, rinse off the surface salt with deionized water, and dry them in an oven at 60±5℃ for 1h. Evaluation criteria: Observe the surface for corrosion spots, rust, or coating blistering, and record the percentage of corrosion area and the diameter of the largest corrosion spot. No obvious corrosion marks are considered "qualified". Corrosion spots with an area of ​​less than 5% are considered "slight corrosion". Corrosion spots with an area of ​​≥5% are considered "severe corrosion".

[0045] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific technical solutions or characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for producing an electrode foil, characterized by, The method comprises the following steps: S1: surface pretreatment: the base electrode foil is sequentially cleaned with deionized water and ethanol by ultrasonic cleaning for 8-12 minutes to remove surface impurities, and then dried in a vacuum degree of 0.04-0.06 MPa and a temperature of 65-75℃ for 12-18 minutes; S2: intermediate reinforcing layer construction: a mixed slurry containing aluminum powder and silica sol is configured, the average particle size of the aluminum powder is 5-15 μm, and the solid content of the silica sol is 20%-30%, the base electrode foil is immersed in the mixed slurry, the mass fraction of aluminum powder in the slurry is 10%-15%, the mass fraction of silica sol is 8%-12%, the electrode foil is taken out after being immersed for 4-6 minutes, pre-dried at 80-100℃ for 15-25 minutes, and then sintered at 450-550℃ for 25-35 minutes in a nitrogen protective atmosphere to form an intermediate conductive reinforcing layer; S3: outer layer functional modification: the electrode foil with the intermediate layer is immersed in a solution containing epoxy resin and silica powder, a uniform coating is formed on the surface of the electrode foil by dip coating, the mass fraction of epoxy resin in the solution is 12%-18%, the mass fraction of silica powder is 3%-5%, the dip coating pulling speed is 5-15 cm / min, and then heat cured at 140-160℃ for 40-50 minutes to construct the outer layer structure.

2. The method of producing an electrode foil according to claim 1, wherein In the surface pretreatment step, the volume concentration of ethanol is 90%-95%.

3. The method for preparing the electrode foil according to claim 1, characterized in that, In the intermediate reinforcing layer construction step, 0.5%-1.5% of stearic acid is added as a dispersant.

4. The method of producing an electrode foil according to claim 1, wherein In the outer layer functional modification step, the average particle size of the silica powder is 1-3 μm.

5. The method for preparing the electrode foil according to claim 1, characterized in that, In the outer layer functional modification step, the heat curing adopts a stepwise heating mode: first heat at 100-120℃ for 20 minutes, and then heat to 140-160℃ for 20-30 minutes.

6. An electrode foil, characterized by, The electrode foil is prepared by the method of any one of claims 1-5.

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