Post-treatment process of composite anode aluminum foil, composite anode aluminum foil and application thereof
By employing a post-processing technique involving composite anode aluminum foil, including immersion in hydrogen peroxide solution and secondary calcination, the problems of microcracks and oxygen vacancies caused by the difference in thermal expansion coefficients between metal oxides and Al2O3 are solved. This results in aluminum electrolytic capacitors with high dielectric constant, low leakage current, and high reliability, making them particularly suitable for high-reliability solid-state capacitors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-21
- Publication Date
- 2026-06-23
AI Technical Summary
In the existing technology, the thermal expansion coefficients of metal oxides and Al2O3 are significantly different, which can easily induce microcracks and pores at the interface and grain boundaries during the cooling process, resulting in increased leakage current. Furthermore, local oxygen-deficient environments or incomplete reactions can easily generate oxygen vacancies, which become deep-level charge traps, further enhancing leakage current. It is difficult to achieve both high dielectric constant and low leakage current.
The post-processing of composite anode aluminum foil includes primary calcination, hydrogen peroxide solution immersion, and secondary calcination. Hydrogen peroxide penetrates into microcracks and pores, decomposes to generate O2 and H2O vapors, forming instantaneous micro-region high-pressure physical repair of defects, and releasing highly active nascent oxidative energy to fill oxygen vacancies, ensuring the full crystallization of the high dielectric constant crystalline phase.
It significantly reduces leakage current, increases breakdown field strength and dielectric constant, and enhances the reliability and lifespan of aluminum electrolytic capacitors, making it particularly suitable for high-reliability solid-state capacitors.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of aluminum electrolytic capacitor technology, and in particular to a post-processing technology for composite anode aluminum foil, the composite anode aluminum foil and its applications. Background Technology
[0002] Aluminum electrolytic capacitors are widely used in consumer electronics, new energy vehicles, and industrial power supplies. The demands for miniaturization and high reliability continue to drive upgrades in the performance of the anode aluminum foil. Traditional etching and anodizing processes result in Al2O3 dielectric layers with low dielectric constants, limiting the improvement of specific capacitance. To address this, existing technologies generally employ a composite strategy: introducing high-dielectric-constant metal oxides onto the etched aluminum foil surface, forming a film through sol-gel methods, liquid phase deposition, or sputtering, followed by calcination to promote precursor decomposition and crystallization, forming an interface bond with the underlying Al2O3, thereby increasing the overall dielectric constant to over 40.
[0003] However, this process has inherent drawbacks: on the one hand, the significant difference in thermal expansion coefficients between metal oxides and Al2O3 easily induces microcracks and pores at the interface and grain boundaries during cooling; on the other hand, localized oxygen-deficient environments or incomplete reactions can easily lead to the formation of oxygen vacancies in the crystal lattice, becoming deep-level charge traps and significantly increasing leakage current. Experiments show that increased leakage current not only accelerates dielectric aging but also directly reduces breakdown field strength and long-term operating life. Especially under high voltage and high temperature conditions, the synergistic effect of these defects is exacerbated, making it difficult to achieve both high dielectric constant and low leakage current. This has become a key technical bottleneck restricting the industrialization of high-performance solid-state capacitors.
[0004] In view of this, the present invention is hereby proposed. Summary of the Invention
[0005] The purpose of this invention is to provide a post-processing method for composite anode aluminum foil, composite anode aluminum foil and its application, aiming to solve at least one of the above-mentioned technical problems in the prior art.
[0006] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: The first aspect of the present invention provides a post-processing process for composite anode aluminum foil, wherein the anode aluminum foil with composite layer is calcined once, then soaked in hydrogen peroxide solution, and finally calcined a second time to obtain composite anode aluminum foil.
[0007] Furthermore, the primary calcination is carried out in the presence of air or oxygen.
[0008] Preferably, the temperature of the first calcination is 400~600℃ and the time is 10~60min.
[0009] Preferably, the heating rate of the first calcination is 3~8℃ / min.
[0010] Furthermore, the concentration of the hydrogen peroxide solution is 5-30 wt%.
[0011] Preferably, the soaking temperature is 20~60℃ and the soaking time is 5~30min.
[0012] Furthermore, the secondary calcination is carried out in the presence of air or oxygen.
[0013] Preferably, the temperature of the secondary calcination is not higher than the temperature of the primary calcination, and the time is 10-40 minutes; Preferably, the temperature of the secondary calcination is 400~600℃.
[0014] Preferably, the heating rate of the secondary calcination is 3~8℃ / min.
[0015] Furthermore, the composite layer is a precursor of a high dielectric constant material.
[0016] Preferably, the dielectric constant of the high dielectric constant material is 25~5000.
[0017] Preferably, the high dielectric constant material includes at least one of titanium dioxide (TiO2), zirconium dioxide (ZrO2), strontium titanate (SrTiO3), and barium titanate (BaTiO3).
[0018] Furthermore, the precursor of the titanium dioxide includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate.
[0019] Preferably, the zirconium dioxide precursor includes at least one of tetrabutyl zirconate, tetraisopropyl zirconate, and propyl zirconate.
[0020] Preferably, the titanium source precursor of the strontium titanate includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate, and the strontium source precursor includes at least one of strontium acetate, strontium nitrate, strontium isopropoxide, strontium chloride, and strontium hydroxide.
[0021] Preferably, the titanium source precursor of the barium titanate includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate, and the barium source precursor includes at least one of barium acetate, barium isopropoxide, barium nitrate, and barium hydroxide.
[0022] Furthermore, the primary calcination and the secondary calcination are each carried out independently in a tubular furnace.
[0023] The second aspect of the present invention provides a composite anode aluminum foil, which is obtained by the post-processing process described in the first aspect.
[0024] Furthermore, the composite anode aluminum foil includes an aluminum foil and a composite dielectric layer wrapping the aluminum foil; wherein the aluminum foil is an aluminum foil after electrochemical etching; and the composite dielectric layer is made of a high dielectric constant material and aluminum oxide.
[0025] The third aspect of this invention provides the application of the composite anode aluminum foil in aluminum electrolytic capacitors.
[0026] Compared with the prior art, the present invention has at least the following beneficial effects: The post-processing technology provided by this invention involves immersing the product in a hydrogen peroxide solution, allowing the hydrogen peroxide to penetrate into the microcracks and pores generated during the first calcination. During the second calcination, the hydrogen peroxide decomposes to produce O2 and H2O vapors, creating a transient micro-region high voltage that physically repairs the defects. Simultaneously, it releases highly reactive nascent oxygen, chemically filling oxygen vacancies and significantly reducing leakage current. Since the first calcination ensures the full crystallization of the high-dielectric-constant phase, subsequent processing does not damage its lattice integrity. Therefore, the dielectric constant is maintained or even slightly improved, while the breakdown field strength is increased and the loss tangent decreases, achieving a balance between high dielectric constant, low leakage current, and high reliability.
[0027] The composite anode aluminum foil provided by this invention, due to the advantages of the above-mentioned post-processing technology, results in a more compact structure and a more stable interface, combining the advantages of high specific capacitance, low leakage current, high withstand voltage and long life. It is particularly suitable for high-reliability solid aluminum electrolytic capacitors, promoting the development of downstream industries. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0029] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.
[0030] The first aspect of the present invention provides a post-processing process for composite anode aluminum foil, wherein the anode aluminum foil with composite layer is calcined once, then soaked in hydrogen peroxide solution, and finally calcined a second time to obtain composite anode aluminum foil.
[0031] The post-processing technology provided by this invention involves immersing the product in a hydrogen peroxide solution, allowing the hydrogen peroxide to penetrate into the microcracks and pores generated during the first calcination. During the second calcination, the hydrogen peroxide decomposes to produce O2 and H2O vapors, creating a transient micro-region high voltage that physically repairs the defects. Simultaneously, it releases highly reactive nascent oxygen, chemically filling oxygen vacancies and significantly reducing leakage current. Since the first calcination ensures the full crystallization of the high-dielectric-constant phase, subsequent processing does not damage its lattice integrity. Therefore, the dielectric constant is maintained or even slightly improved, while the breakdown field strength is increased and the loss tangent decreases, achieving a balance between high dielectric constant, low leakage current, and high reliability.
[0032] Furthermore, the primary calcination is carried out in the presence of air or oxygen, transforming the precursor into the target high dielectric constant material.
[0033] Preferably, the calcination temperature is 400~600℃ and the time is 10~60min. Under these conditions, the precursor decomposes and crystallizes, combining with the alumina substrate on the aluminum foil surface to form an initial composite dielectric layer, but this layer contains microcracks and oxygen vacancies.
[0034] Typically, but not limitingly, the temperature of a single calcination can be, for example, 400°C, 450°C, 500°C, 550°C, or 600°C, or any value within the range of 400°C to 600°C; the time of a single calcination can be, for example, 10 min, 20 min, 30 min, 40 min, 50 min, or 60 min, or any value within the range of 10 to 60 min.
[0035] Preferably, the heating rate of the first calcination is 3~8℃ / min.
[0036] Typical, but not limiting, heating rates for a single calcination can be, for example, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, or 8°C / min, or any value in the range of 3 to 8°C / min.
[0037] Furthermore, the concentration of the hydrogen peroxide solution is 5-30 wt%. If the concentration is below 5 wt%, the repair effect is not obvious; if the concentration is above 30 wt%, it is not economical and decomposes too quickly.
[0038] Typical, but not limiting, concentrations of hydrogen peroxide solutions can be, for example, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%, or any value in the range of 5 to 30 wt%.
[0039] Preferably, the soaking temperature is 20~60℃ and the time is 5~30min, allowing the hydrogen peroxide solution to penetrate into the microscopic defects (such as microcracks and pores) generated after the first calcination.
[0040] Typically, but not limitingly, the soaking temperature can be, for example, 20°C, 30°C, 40°C, 50°C, or 60°C, or any value within the range of 20°C to 60°C; the soaking time can be, for example, 5 min, 10 min, 15 min, 20 min, 25 min, or 30 min, or any value within the range of 5 to 30 min.
[0041] Furthermore, the secondary calcination is carried out in the presence of air or oxygen.
[0042] Preferably, the temperature of the secondary calcination is not higher than the temperature of the primary calcination, and the time is 10-40 minutes, so as to achieve the repair effect while avoiding excessive crystallization or damage to the composite dielectric layer.
[0043] Typical, but not limiting, the time for secondary calcination can be, for example, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, or 40 min, or any value within the range of 10 to 40 min.
[0044] Preferably, the secondary calcination temperature is 400-600℃, which causes the hydrogen peroxide that has permeated into the defects to decompose rapidly. The large amount of gas (oxygen and water vapor) produced by the decomposition generates instantaneous local high pressure within the sealed micro-defects. This micro-area compression effect can effectively close and compact microcracks. The nascent oxygen produced by the decomposition is highly reactive and can effectively fill and repair oxygen vacancies formed during the first calcination, reducing the charge trap density.
[0045] Preferably, the heating rate of the secondary calcination is 3~8℃ / min.
[0046] Typical, but not limiting, heating rates for secondary calcination can be, for example, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, or 8°C / min, or any value in the range of 3 to 8°C / min.
[0047] Furthermore, the composite layer is a precursor of a high dielectric constant material.
[0048] This invention does not limit the formation process of the composite layer; any conventional or equivalent preparation method that can achieve the target composite layer structure and performance requirements is within the scope of protection of this invention. For example, the composite layer can be prepared by processes such as sol-gel method, liquid phase deposition method, or sputtering method in physical vapor deposition.
[0049] Taking the sol-gel method as an example: the metal oxide precursor can be dissolved or hydrolyzed and dispersed in a suitable solvent to prepare a stable and uniform precursor sol; then, film-forming techniques such as dip coating, dip coating or spin coating are used to form a wet gel coating with controllable thickness and uniform distribution on the surface of a clean aluminum foil substrate; then, it is dried at low temperature to remove the solvent and some organic components to obtain a composite layer with a preliminary network structure.
[0050] Preferably, the dielectric constant of the high dielectric constant material is 25~5000.
[0051] Preferably, the high dielectric constant material includes at least one of titanium dioxide (TiO2), zirconium dioxide (ZrO2), strontium titanate (SrTiO3), and barium titanate (BaTiO3).
[0052] Furthermore, the precursor of the titanium dioxide includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate.
[0053] Preferably, the zirconium dioxide precursor includes at least one of tetrabutyl zirconate, tetraisopropyl zirconate, and propyl zirconate.
[0054] Preferably, the titanium source precursor of the strontium titanate includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate, and the strontium source precursor includes at least one of strontium acetate, strontium nitrate, strontium isopropoxide, strontium chloride, and strontium hydroxide.
[0055] Preferably, the titanium source precursor of the barium titanate includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate, and the barium source precursor includes at least one of barium acetate, barium isopropoxide, barium nitrate, and barium hydroxide.
[0056] Furthermore, the primary calcination and the secondary calcination are each carried out independently in a tubular furnace.
[0057] The second aspect of the present invention provides a composite anode aluminum foil, which is obtained by the post-processing process described in the first aspect.
[0058] The composite anode aluminum foil provided by this invention, due to the advantages of the above-mentioned post-processing technology, results in a more compact structure and a more stable interface, combining the advantages of high specific capacitance, low leakage current, high withstand voltage and long life. It is particularly suitable for high-reliability solid aluminum electrolytic capacitors, promoting the development of downstream industries.
[0059] Furthermore, the composite anode aluminum foil includes an aluminum foil and a composite dielectric layer wrapping the aluminum foil; wherein the aluminum foil is an aluminum foil after electrochemical etching; and the composite dielectric layer is made of a high dielectric constant material and aluminum oxide.
[0060] The third aspect of this invention provides the application of the composite anode aluminum foil in aluminum electrolytic capacitors.
[0061] The present invention is further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for illustrative purposes and should not be construed as limiting the invention in any way. Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present invention were carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0062] Example 1 This embodiment provides a composite anode aluminum foil, and the specific preparation method is as follows: 1. Provide an electrochemically etched anolyte aluminum foil substrate with a thickness of 110 μm and a uniform tunnel hole structure on the surface. Cut it into 10 cm × 10 cm samples, and ultrasonically clean it sequentially with acetone, ethanol, and deionized water for 10 minutes each, then dry it in an 80°C oven for later use.
[0063] 2. Slowly add 10 mL of tetrabutyl titanate to 40 mL of anhydrous ethanol. While stirring, add 2 mL of acetylacetone as a stabilizer and continue stirring for 30 minutes to obtain a clear solution. Using the dip-pull method, immerse the cleaned aluminum foil at a uniform speed of 2 mm / s into the liquid and pull it out of the liquid. Dry at 80°C for 10 minutes to form a uniform gel coating.
[0064] 3. The aluminum foil coated with gel is placed in a temperature-controlled tube furnace and calcined for the first time in an air atmosphere. The calcination program is as follows: the temperature is increased to 600℃ at a rate of 5℃ / min, held for 20 minutes, and then naturally cooled to room temperature with the furnace. During this process, the precursor decomposes and crystallizes, combining with the alumina substrate on the surface of the aluminum foil to form the initial TiO2 / Al2O3 composite dielectric layer.
[0065] 4. Immerse the aluminum foil, after its first calcination, completely in a 15% (w / w) hydrogen peroxide aqueous solution at 40°C for 15 minutes. During immersion, fine bubbles will be observed on the surface of the aluminum foil, indicating that H2O2 has penetrated and begun to react at microscopic defects. After immersion, remove the aluminum foil, rinse off any residual liquid with deionized water, and dry it with nitrogen gas.
[0066] 5. The soaked aluminum foil is placed again in a tube furnace and calcined a second time in an air atmosphere. The calcination procedure is as follows: the temperature is increased to 560°C at a rate of 5°C / min, held for 10 minutes, and then cooled to room temperature with the furnace to obtain an anode aluminum foil with a dense and complete TiO2 / Al2O3 composite dielectric layer on the surface.
[0067] Comparative Example 1 This comparative example provides a composite anode aluminum foil. Unlike Example 1, steps 4 and 5 are omitted. The remaining steps are the same as in Example 1 and will not be repeated here.
[0068] Comparative Example 2 This comparative example provides a composite anode aluminum foil. Unlike Example 1, step 5 is as follows: after soaking in hydrogen peroxide and cleaning and drying, no second calcination is performed, and it is directly used as the final sample. The remaining steps are the same as in Example 1, and will not be repeated here.
[0069] Comparative Example 3 This comparative example provides a composite anode aluminum foil. Unlike Example 1, it does not involve soaking in hydrogen peroxide aqueous solution. Instead, the aluminum foil after the first calcination is directly calcined a second time. The remaining steps are the same as in Example 1 and will not be repeated here.
[0070] Test Example 1 The composite anode aluminum foils obtained in Example 1 and Comparative Examples 1-3 were cut into 1cm × 1cm test units, and circular aluminum electrodes (5 mm in diameter) were fabricated on their surfaces using vacuum evaporation to form a metal-insulator-metal (MIM) capacitor structure. Performance tests were performed at room temperature using a precision LCR meter (Keysight E4980A) and a semiconductor parameter analyzer (Keysight B1500A), and the results are summarized in Table 1 below.
[0071] Table 1. Electrical performance test results of composite anode aluminum foil
[0072] As shown in Table 1, the leakage current density of Example 1 is lower than that of Comparative Examples 1-3. The leakage current of Example 1 is reduced by approximately 48.78% compared to Comparative Example 1, fully demonstrating the superior effect of hydrogen peroxide immersion and secondary calcination processes in repairing microcracks and filling oxygen vacancies. The limited performance improvement in Comparative Example 2 indicates that the H2O2 decomposition and repair reaction mainly occur during the second calcination process, and both are indispensable. While effectively repairing defects, the dielectric constant of Example 1 of this invention is not lower than, and may even be higher than, that of Comparative Example 1 using traditional processes. The breakdown field strength of Example 1 is higher than that of Comparative Examples 1-3, indicating that the repaired dielectric layer structure is denser and more complete, with fewer internal defects, thereby improving the long-term operational reliability and withstand voltage of the capacitor.
[0073] Example 2 This embodiment provides a composite anode aluminum foil. The difference from Embodiment 1 is that the calcination temperature in step 5 is 600°C. The other raw materials and preparation methods are the same as in Embodiment 1, and will not be repeated here.
[0074] Example 3 This embodiment provides a composite anode aluminum foil. The difference from Embodiment 1 is that the calcination temperature in step 5 is 630°C. The other raw materials and preparation methods are the same as in Embodiment 1, and will not be repeated here.
[0075] Example 4 This embodiment provides a composite anode aluminum foil. The difference from Example 1 is that the concentration of the H2O2 solution is 3wt%. The other raw materials and preparation methods are the same as in Example 1, and will not be repeated here.
[0076] Example 5 This embodiment provides a composite anode aluminum foil. The difference from Example 1 is that the concentration of the H2O2 solution is 5wt%. The other raw materials and preparation methods are the same as in Example 1, and will not be repeated here.
[0077] Example 6 This embodiment provides a composite anode aluminum foil. The difference from Example 1 is that the concentration of the H2O2 solution is 30wt%. The other raw materials and preparation methods are the same as in Example 1, and will not be repeated here.
[0078] Example 7 This embodiment provides a composite anode aluminum foil. The difference from Example 1 is that the concentration of the H2O2 solution is 35wt%. The other raw materials and preparation methods are the same as in Example 1, and will not be repeated here.
[0079] Example 8 This embodiment provides a composite anode aluminum foil. Unlike Example 1, in step 2, 10 mL of tetrabutyl zirconate (80 wt% n-butanol solution) is slowly added dropwise to 40 mL of anhydrous ethanol. During stirring, 2 mL of acetylacetone is added as a stabilizer, and stirring continues for 30 minutes to obtain a clear solution. Using the dip-pull method, the cleaned aluminum foil is immersed in the liquid at a uniform speed of 2 mm / s and then pulled out of the liquid surface. It is then dried at 80°C for 10 minutes to form a uniform gel coating. Correspondingly, in step 3, the initial ZrO2 / Al2O3 composite dielectric layer is formed. The remaining steps and preparation methods are the same as in Example 1 and will not be repeated here.
[0080] Example 9 This embodiment provides a composite anode aluminum foil. Unlike Embodiment 1, in step 2, 10.3g of strontium acetate is weighed and added to 100mL of glacial acetic acid. The solution is stirred at 40-60℃ until completely dissolved, yielding a colorless and transparent solution A. 17mL of tetrabutyl titanate is slowly added dropwise to 80mL of anhydrous ethanol. During stirring, 5.2mL of acetylacetone is added as a stabilizer, and stirring continues for 30 minutes, yielding a yellow and transparent solution B. Under room temperature and vigorous stirring conditions, solution A is slowly added dropwise to solution B. After the addition is complete, stirring continues for 1 hour, yielding a clear and stable strontium-titanium composite precursor sol solution C. This solution is allowed to stand for 12 hours before use. Using the dip-pull method, the cleaned aluminum foil is uniformly immersed in solution C at a speed of 2mm / s and then pulled out of the liquid surface. It is then dried at 80℃ for 10 minutes to form a uniform gel coating. Correspondingly, in step 3, an initial SrTiO3 / Al2O3 composite dielectric layer is formed. The remaining steps and preparation methods are the same as in Example 1, and will not be repeated here.
[0081] Example 10 This embodiment provides a composite anode aluminum foil. Unlike Embodiment 1, in step 2, 12.8g of barium acetate is weighed and added to 100mL of glacial acetic acid, stirred at 40-60℃ until completely dissolved, yielding a colorless and transparent solution A. 17mL of tetrabutyl titanate is slowly added dropwise to 80mL of anhydrous ethanol, with 5.2mL of acetylacetone added as a stabilizer during stirring. Stirring continues for 30 minutes, yielding a yellow and transparent solution B. Under room temperature and vigorous stirring conditions, solution A is slowly added dropwise to solution B. After the addition is complete, stirring continues for 1 hour, yielding a clear and stable barium-titanium composite precursor sol solution C. This solution is allowed to stand for 12 hours before use. Using the dip-pull method, the cleaned aluminum foil is uniformly immersed in solution C at a speed of 2mm / s and then pulled out of the liquid surface. It is then dried at 80℃ for 10 minutes to form a uniform gel coating. Correspondingly, in step 3, the initial BaTiO3 / Al2O3 composite dielectric layer is formed. The remaining steps and preparation methods are the same as in Example 1, and will not be repeated here.
[0082] Comparative Example 4 This comparative example provides a composite anode aluminum foil. Unlike Example 8, steps 4 and 5 are omitted. The remaining steps are the same as in Example 8 and will not be repeated here.
[0083] Comparative Example 5 This comparative example provides a composite anode aluminum foil. Unlike Example 9, steps 4 and 5 are omitted. The remaining steps are the same as in Example 9 and will not be repeated here.
[0084] Comparative Example 6 This comparative example provides a composite anode aluminum foil. Unlike Example 10, steps 4 and 5 are omitted. The remaining steps are the same as in Example 10 and will not be repeated here.
[0085] Test Example 2 The composite anode aluminum foils obtained in Examples 2-10 and Comparative Examples 4-6 were subjected to performance tests, and the test methods were the same as those in Test Example 1. The results are summarized in Table 2 below.
[0086] Table 2 Electrical performance test results of composite anode aluminum foil
[0087] As shown in Table 2, the post-processing technology of this invention exhibits significant performance improvement under different materials and process parameters. Comparing Examples 1-3, it is evident that the secondary calcination temperature should not exceed the primary calcination temperature (600℃). When the secondary calcination temperature in Example 3 rises to 630℃, the leakage current increases significantly, and the breakdown field strength decreases, indicating that excessively high temperatures may cause thermal damage to the crystallized dielectric layer. Comparing Examples 1 and 4-7, it is clear that the hydrogen peroxide concentration is crucial to the repair effect. In Example 4, the concentration of 3wt% is too low, resulting in insufficient repair and a still high leakage current. In Example 7, the concentration of 35wt% is too high, which may cause excessively vigorous decomposition and generate new impacts on the dielectric layer, weakening the performance improvement effect. In Examples 1 and 5-6, excellent comprehensive performance can be obtained when the concentration is in the range of 5-30wt%. Furthermore, when the process of this invention was applied to high dielectric constant materials such as ZrO2 in Example 8, SrTiO3 in Example 9, and BaTiO3 in Example 10, the leakage current was significantly reduced by approximately 46%-50% compared to the untreated comparative examples 4-6, and the dielectric constant and breakdown field strength were also improved, fully demonstrating the wide applicability and significant beneficial effects of the technical solution of this invention. Among them, the titanate systems in Examples 9-10, which have even higher dielectric constants, exhibited better potential for capacitance performance after treatment.
[0088] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A post-processing technology for composite anode aluminum foil, characterized in that, The composite anode aluminum foil is obtained by first calcining, then soaking in hydrogen peroxide solution, and finally calcining a second time.
2. The post-processing technique according to claim 1, characterized in that, The first calcination is carried out in the presence of air or oxygen. Preferably, the temperature of the first calcination is 400~600℃ and the time is 10~60min; Preferably, the heating rate of the first calcination is 3~8℃ / min.
3. The post-processing technique according to claim 1, characterized in that, The concentration of the hydrogen peroxide solution is 5-30 wt%; Preferably, the soaking temperature is 20~60℃ and the soaking time is 5~30min.
4. The post-processing technique according to claim 1, characterized in that, The secondary calcination is carried out in the presence of air or oxygen. Preferably, the temperature of the secondary calcination is not higher than the temperature of the primary calcination, and the time is 10-40 minutes; Preferably, the temperature of the secondary calcination is 400~600℃; Preferably, the heating rate of the secondary calcination is 3~8℃ / min.
5. The post-processing method according to any one of claims 1 to 4, characterized in that, The composite layer is a precursor of a high dielectric constant material; Preferably, the dielectric constant of the high dielectric constant material is 25~5000; Preferably, the high dielectric constant material includes at least one of titanium dioxide (TiO2), zirconium dioxide (ZrO2), strontium titanate (SrTiO3), and barium titanate (BaTiO3).
6. The post-processing technique according to claim 5, characterized in that, The precursor of titanium dioxide includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate. Preferably, the zirconium dioxide precursor includes at least one of tetrabutyl zirconate, tetraisopropyl zirconate, and propyl zirconate; Preferably, the titanium source precursor of the strontium titanate includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate, and the strontium source precursor includes at least one of strontium acetate, strontium nitrate, strontium isopropoxide, strontium chloride, and strontium hydroxide. Preferably, the titanium source precursor of the barium titanate includes at least one of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate, and the barium source precursor includes at least one of barium acetate, barium isopropoxide, barium nitrate, and barium hydroxide.
7. The post-processing method according to any one of claims 1 to 4, characterized in that, The primary calcination and the secondary calcination are each carried out independently in a tubular furnace.
8. A composite anode aluminum foil, characterized in that, It is obtained by post-processing according to any one of claims 1 to 7.
9. The composite anode aluminum foil according to claim 8, characterized in that, Includes an aluminum foil and a composite dielectric layer that wraps the aluminum foil; The aluminum foil is an aluminum foil that has been electrochemically etched. The composite dielectric layer is made of a high dielectric constant material and aluminum oxide.
10. The application of the composite anode aluminum foil according to claim 9 in an aluminum electrolytic capacitor.