A method for manufacturing a high specific capacity layer-type electrode foil
By leveraging the synergistic effects of modified acid mixtures, corrosion modifiers, and formation modifiers, the problems of uneven etching and incomplete oxide film in improving the specific capacity of electrode foil were solved, thus enabling the manufacture of electrode foils with high specific capacity, high pressure resistance, and high temperature stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG NANHUI ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2026-06-10
- Publication Date
- 2026-07-10
Smart Images
Figure CN122370192A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrode foil manufacturing technology, specifically to a method for manufacturing a high specific volume layer electrode foil. Background Technology
[0002] Anode foil for aluminum electrolytic capacitors is a core material for the miniaturization and lightweighting of electronic devices. With the increasing demand for high energy density and high voltage in capacitors from fields such as 5G communication, new energy vehicles, and industrial power supplies, how to significantly increase the specific capacitance per unit area of electrode foil within a limited volume has become a key bottleneck that urgently needs to be overcome in the field of electrode foil manufacturing technology.
[0003] Currently, the industry's technical approaches to improving the specific capacitance of electrode foil mainly focus on two areas: one is to construct tunnels with higher density and deeper aspect ratios during the etching process to expand the effective specific surface area; the other is to generate composite oxide films with higher dielectric constants during the formation process to enhance the charge storage capacity per unit area. However, both of these approaches face significant limitations in practical applications.
[0004] In terms of corrosion processes, existing technologies mostly employ a hydrochloric acid-sulfuric acid mixed acid system for direct current electrochemical corrosion. While this system can form tunnel pores on the aluminum foil surface, it suffers from limitations due to the presence of Cl... - With SO4 2- Insufficiently fine competitive adsorption on the surface can easily lead to the following problems: uneven pit formation, excessive corrosion in localized areas resulting in abnormally large pores or surface surface erosion; severe lateral expansion of pits, limiting the aspect ratio and making it difficult to form deep and straight tunnel structures. This not only limits the further increase of the effective specific surface area but also leads to a decrease in the mechanical strength of the foil, making it prone to breakage during subsequent processing.
[0005] Therefore, there is an urgent need to develop an integrated manufacturing method that can control the interface from the corrosion and pitting stage, achieve in-situ uniform doping in the formation stage, and ensure the integrity of the film layer under high pressure, so as to realize the large-scale preparation of high specific volume layer electrode foil. Summary of the Invention
[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for manufacturing a high specific volume layer electrode foil.
[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for manufacturing a high specific volume layer electrode foil includes the following steps: S1. Aluminum foil corrosion modification: High-purity aluminum foil is immersed in corrosion modifier for 10-20 minutes, and then removed to obtain corrosion-modified aluminum foil; S2. Aluminum foil formation modification: After cleaning the etched modified aluminum foil obtained in step S1 with deionized water, it is added to the formation modifier and the formation time is 60-90 min to obtain the formation modified aluminum foil. S3. Aluminum foil post-processing: Take out the chemically modified aluminum foil obtained in step S2, wash it with deionized water, and anneal it for 1-3 minutes to finally obtain a high specific volume layer electrode foil. The preparation of the corrosion modifier includes the following steps: S11. By weight, mix 50-65 parts of modified acid mixture with 20-40 parts of deionized water and stir at 100-200 r / min until the mixture is uniform. S12. Add 10-15 parts of ethylene glycol and 2-5 parts of polyethylene glycol-400 to the mixed solution obtained in step S11, and stir at a speed of 200-300 r / min for 10-15 min; S13. Add 1-3 parts of cerium ammonium nitrate to the mixed solution obtained in step S12, stir at 200-300 r / min until dissolved, and let stand for 20-30 min to remove bubbles to obtain the corrosion modifier.
[0008] Preferably, the preparation of the modified acid mixture includes the following steps: S111. By mass, 60-72 parts of hydrochloric acid solution with a mass concentration of 36-38% and 15-22 parts of sulfuric acid solution with a mass concentration of 98% are mixed evenly at 30-40℃ to obtain a first-grade acid solution; S112. Add 8-12 parts of 85% phosphoric acid solution and 3-6 parts of citric acid to the primary acid solution obtained in step S111, and stir at 300-400 r / min for 5-10 min to obtain the secondary acid solution. S113. Add 0.1-0.3 parts of nano silica sol (acid-stable type, pH 2-4, particle size 5-15nm) and 2-5 parts of urea to the secondary acid solution obtained by S112, and stir at 400-500r / min for 15-20min to obtain the modified acid mixture.
[0009] Preferably, the preparation of the chemical modifier includes the following steps: S21. By mass, 40-60 parts of deionized water, 15-25 parts of ammonium pentaborate, and 20-30 parts of ammonium adipate are stirred at 50-60°C until completely dissolved to obtain a primary chemical agent; S22. Add 0.5-1 parts of ammonium dihydrogen phosphate and 0.1-0.5 parts of ammonium hypophosphite to the primary forming agent obtained in step S21, and stir at a speed of 200-300 r / min for 10-15 min to obtain the secondary forming agent; S23. Add 0.05-0.2 parts of metatitanic acid and 3-8 parts of glycerol to the secondary forming agent obtained in step S22 under stirring at 45-50℃. After the addition is complete, continue stirring for 20-30 minutes. After filtration through a 0.45μm filter membrane, the forming modifier is obtained.
[0010] Preferably, the aluminum foil etching modification process in step S1 is carried out at a current density of 0.2-0.5 A / cm². 2 It is carried out in direct current.
[0011] Preferably, the immersion temperature in the aluminum foil corrosion modification process of step S1 is 60-80℃.
[0012] Preferably, the aluminum foil formation and modification process in step S2 is carried out at a current density of 0.3-0.5 A / cm². 2 The conversion is carried out under direct current, with a conversion voltage of 200-500V.
[0013] Preferably, the formation temperature for aluminum foil formation modification in step S2 is 80-90℃.
[0014] Preferably, the annealing temperature in step S3 is 300-500℃.
[0015] Preferably, the stirring speed in step S23 is 300-400 r / min.
[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention significantly improves the pit density through a corrosion modifier, laying the foundation for increasing the specific surface area. Simultaneously, it refines the microcrystalline structure of the oxide film, inhibiting the crystal transformation and film cracking of alumina at high temperatures, greatly improving the thermal stability of the oxide film, and reducing the risk of high-temperature leakage current degradation. The modified acid mixture provides a uniformly distributed substrate for the corrosion modifier's corrosion inhibition system. The formation modifier achieves multiple performance breakthroughs in high-pressure formation, effectively suppressing the anodic oxygen evolution side reaction, fundamentally reducing pinholes and microcracks caused by bubble desorption within the oxide film, achieving high dielectric doping, oxygen evolution suppression, and in-situ defect repair, ensuring the density and integrity of the high-pressure composite oxide film.
[0017] 2. This invention achieves technical effects that traditional single-process improvements cannot achieve through the synergistic effect of modified acid mixture, corrosion modifier and formation modifier, resulting in a significant improvement in the specific capacity, withstand voltage strength and high temperature reliability of the final electrode foil. Attached Figure Description
[0018] Figure 1 This is a process flow diagram for the preparation of the high specific volume layer electrode foil of the present invention; Figure 2 This is a flow chart of the preparation process of the corrosion modifier of the present invention; Figure 3 This is a flow chart of the preparation process of the chemical modification agent of the present invention; Figure 4 This is a flow chart of the preparation process of the modified acid mixture of the present invention. Detailed Implementation
[0019] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0020] Please see Figures 1-4 The present invention provides a technical solution: Example 1 A method for manufacturing a high specific volume layer electrode foil: Before manufacturing high specific volume layered electrode foil, the modified acid mixture, etching modifier, and formation modifier are prepared: The preparation of the modified acid mixture includes the following steps: S111. Mix 60g of 36% hydrochloric acid solution and 15g of 98% sulfuric acid solution at 30°C until homogeneous to obtain a primary acid solution; S112. Add 8g of 85% phosphoric acid solution and 3g of citric acid to the primary acid solution obtained in step S111, and stir at 300r / min for 5min to obtain the secondary acid solution. S113. Add 0.1g of nano silica sol and 2g of urea to the secondary acid solution obtained from S112, and stir at 400r / min for 15min to obtain the modified acid mixture.
[0021] The preparation of the corrosion modifier includes the following steps: S11. Mix 50g of modified acid mixture with 20g of deionized water and stir at 100r / min until the mixture is uniform. S12. Add 10g of ethylene glycol and 2g of polyethylene glycol-400 to the mixed solution obtained in step S11, and stir at 200r / min for 10min; S13. Add 1g of cerium ammonium nitrate to the mixed solution obtained in step S12, stir at 200r / min until dissolved, and let stand for 20min to remove bubbles to obtain the corrosion modifier.
[0022] The preparation of the chemical modification agent includes the following steps: S21. Stir 40g of deionized water, 15g of ammonium pentaborate and 20g of ammonium adipate at 50°C until completely dissolved to obtain a primary forming agent; S22. Add 0.5g of ammonium dihydrogen phosphate and 0.1g of ammonium hypophosphite to the primary forming agent obtained in step S21, and stir at 200r / min for 10min to obtain the secondary forming agent; S23. Add 0.05g metatitanic acid and 3g glycerol to the secondary forming agent obtained in step S22 while stirring at 45℃ and 300r / min. After the addition is complete, continue stirring for 20min. After filtration through a 0.45μm filter membrane, the forming modifier is obtained.
[0023] Manufacturing method of high specific volume layer electrode foil: S1. Aluminum foil corrosion modification: High-purity aluminum foil is immersed in a corrosion modifier at a temperature of 60℃ for 10 minutes, with a current density of 0.2 A / cm². 2 Direct current is applied to obtain corrosion-modified aluminum foil with a layered structure; S2. Aluminum foil formation modification: After cleaning the etched modified aluminum foil obtained in step S1 with deionized water, it is added to the formation modifier. The formation voltage is 200V and the current density is 0.3A / cm². 2 A direct current was applied, the formation temperature was 80℃, and the formation time was 60 min to obtain the modified aluminum foil. S3. Aluminum foil post-treatment: Take out the chemically modified aluminum foil obtained in step S2, wash it with deionized water, and anneal it at 300°C for 1 minute to finally obtain a high specific volume layer electrode foil.
[0024] Example 2 A method for manufacturing a high specific volume layer electrode foil: Before manufacturing high specific volume layered electrode foil, the modified acid mixture, etching modifier, and formation modifier are prepared: The preparation of the modified acid mixture includes the following steps: S111. Mix 72g of 38% hydrochloric acid solution and 22g of 98% sulfuric acid solution at 40°C until homogeneous to obtain a primary acid solution; S112. Add 12g of 85% phosphoric acid solution and 6g of citric acid to the primary acid solution obtained in step S111, and stir at 400r / min for 10min to obtain the secondary acid solution. S113. Add 0.3g of nano silica sol and 5g of urea to the secondary acid solution obtained from S112, and stir at 500r / min for 20min to obtain the modified acid mixture.
[0025] The preparation of the corrosion modifier includes the following steps: S11. Mix 65g of modified acid mixture with 40g of deionized water and stir at 200r / min until the mixture is uniform. S12. Add 15g of ethylene glycol and 5g of polyethylene glycol-400 to the mixed solution obtained in step S11, and stir at 300r / min for 15min; S13. Add 3g of cerium ammonium nitrate to the mixed solution obtained in step S12, stir at 300r / min until dissolved, and let stand for 30min to remove bubbles to obtain the corrosion modifier.
[0026] The preparation of the chemical modification agent includes the following steps: S21. Stir 60g of deionized water, 25g of ammonium pentaborate and 30g of ammonium adipate at 60°C until completely dissolved to obtain a primary forming agent; S22. Add 1g of ammonium dihydrogen phosphate and 0.5g of ammonium hypophosphite to the primary forming agent obtained in step S21, and stir at 300r / min for 15min to obtain the secondary forming agent; S23. Add 0.2g metatitanic acid and 8g glycerol to the secondary forming agent obtained in step S22 while stirring at 50℃ and 400r / min. After the addition is complete, continue stirring for 30min. After filtration through a 0.45μm filter membrane, the forming modifier is obtained.
[0027] Manufacturing method of high specific volume layer electrode foil: S1. Aluminum foil corrosion modification: High-purity aluminum foil is immersed in a corrosion modifier at an immersion temperature of 80℃ for 20 minutes, with a current density of 0.5 A / cm². 2 Direct current is applied to obtain corrosion-modified aluminum foil with a layered structure; S2. Aluminum foil formation modification: After cleaning the etched modified aluminum foil obtained in step S1 with deionized water, it is added to the formation modifier. The formation voltage is 500V and the current density is 0.5A / cm². 2 A direct current was applied, the formation temperature was 90℃, and the formation time was 90 min to obtain the modified aluminum foil. S3. Aluminum foil post-treatment: Take out the chemically modified aluminum foil obtained in step S2, wash it with deionized water, and anneal it at 500℃ for 3 minutes to finally obtain a high specific volume layer electrode foil.
[0028] Example 3 A method for manufacturing a high specific volume layer electrode foil: Before manufacturing high specific volume layered electrode foil, the modified acid mixture, etching modifier, and formation modifier are prepared: The preparation of the modified acid mixture includes the following steps: S111. Mix 65g of 37% hydrochloric acid solution and 17g of 98% sulfuric acid solution at 32°C until homogeneous to obtain a primary acid solution; S112. Add 10g of 85% phosphoric acid solution and 4g of citric acid to the primary acid solution obtained in step S111, and stir at 320r / min for 6min to obtain the secondary acid solution. S113. Add 0.2g of nano silica sol and 3g of urea to the secondary acid solution obtained from S112, and stir at 420r / min for 16min to obtain the modified acid mixture.
[0029] The preparation of the corrosion modifier includes the following steps: S11. Mix 55g of modified acid mixture with 30g of deionized water and stir at 120r / min until the mixture is uniform. S12. Add 12g of ethylene glycol and 3g of polyethylene glycol-400 to the mixed solution obtained in step S11, and stir at 220r / min for 12min; S13. Add 2g of cerium ammonium nitrate to the mixed solution obtained in step S12, stir at 220r / min until dissolved, and let stand for 22min to remove bubbles to obtain the corrosion modifier.
[0030] The preparation of the chemical modification agent includes the following steps: S21. Stir 45g of deionized water, 20g of ammonium pentaborate and 22g of ammonium adipate at 52°C until completely dissolved to obtain a primary forming agent; S22. Add 0.6g of ammonium dihydrogen phosphate and 0.3g of ammonium hypophosphite to the primary forming agent obtained in step S21, and stir at 220r / min for 12min to obtain the secondary forming agent; S23. Add 0.1g metatitanic acid and 5g glycerol to the secondary forming agent obtained in step S22 while stirring at 47℃ and 320r / min. After the addition is complete, continue stirring for 22min. After filtration through a 0.45μm filter membrane, the forming modifier is obtained.
[0031] Manufacturing method of high specific volume layer electrode foil: S1. Aluminum foil corrosion modification: High-purity aluminum foil is immersed in a corrosion modifier at a temperature of 70℃ for 12 minutes, with a current density of 0.4 A / cm². 2 Direct current is applied to obtain corrosion-modified aluminum foil with a layered structure; S2. Aluminum foil formation modification: After cleaning the etched modified aluminum foil obtained in step S1 with deionized water, it is added to the formation modifier. The formation voltage is 300V and the current density is 0.4A / cm². 2A direct current was applied, the formation temperature was 85℃, and the formation time was 70 min to obtain the modified aluminum foil. S3. Aluminum foil post-treatment: Take out the chemically modified aluminum foil obtained in step S2, wash it with deionized water, and anneal it at 400℃ for 2 minutes to finally obtain a high specific volume layer electrode foil.
[0032] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the modified acid mixture is replaced with a mixture of hydrochloric acid and sulfuric acid in a mass ratio of 4:1 in this comparative example. The remaining steps are exactly the same in Comparative Example 1 and Example 1.
[0033] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the corrosion modifier in this comparative example is replaced with a mixture of hydrochloric acid and sulfuric acid in a mass ratio of 4:1. The remaining steps are exactly the same in Comparative Example 2 and Example 1.
[0034] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the formation modifier in this comparative example is replaced with a mixture of ammonium pentaborate and ammonium adipate in a mass ratio of 2:3. The remaining steps are exactly the same in Comparative Example 3 and Example 1.
[0035] Performance testing: The high specific capacitance layer electrode foils obtained in Examples 1-3 and Comparative Examples 1-3 were tested according to SJ / T 11140-2022 "Electrode Foil for Aluminum Electrolytic Capacitors", GB / T 3615-2016 "Aluminum Foil for Electrolytic Capacitors" and SJ / T 10557.1-2022 "Technical Conditions for Aluminum Foil for Electrolytic Capacitors".
[0036] Samples of 50 mm × 30 mm were cut from the high specific volume layer electrode foils obtained in Examples 1-3 and Comparative Examples 1-3. These samples were ultrasonically cleaned with anhydrous ethanol for 10 min, dried at 50°C for 10 min, and cooled to room temperature. The electrolyte was a 3% ammonium borate aqueous solution (pH 6.5-7.0); the test temperature was 30°C; the test frequency was 120 Hz; and the AC signal voltage was 0.5 V (RMS). The sample was fully immersed in a constant-temperature electrolytic cell containing a 3% ammonium borate aqueous solution (the liquid level ≥ 10 mm above the upper edge of the sample). The sample was used as the working anode, and a large-area graphite plate as the cathode. An LCR digital bridge was used at 0.9 kV·cm⁻¹. -1 The capacitance of the sample was measured under weak field conditions, and the specific capacitance was obtained by reading the capacitance value.
[0037] A 50mm × 30mm sample was cut from the high specific volume layer electrode foil obtained in Examples 1-3 and Comparative Examples 1-3, connected to a leakage current tester, and a graphite plate was used as the cathode. The current was constant and the voltage was increased to the rated formation voltage (the voltage increase mode was consistent with the formation conditions of each example / comparative example). The voltage was then kept constant for 60s at this rated formation voltage, and the leakage current value I after relative stability was recorded. The leakage current was calculated from the effective area of the sample.
[0038] Samples of 50mm × 30mm were cut from the high specific volume layer electrode foils obtained in Examples 1-3 and Comparative Examples 1-3, and connected to a leakage current tester at 1.0mA / cm. 2 A constant current density voltage is used to increase the voltage, and the time taken for the voltage to rise to 90% of the rated formation voltage is recorded. The voltage value, i.e., the withstand voltage value, is recorded when the voltage is increased for another 180 seconds.
[0039] According to the high-temperature leakage current testing conditions of IEC 60384-4 standard, in a constant temperature environment of 125℃, two samples of the same size from the high specific volume layer electrode foils obtained in Examples 1-3 and Comparative Examples 1-3 were taken respectively. One sample was tested at room temperature of 25℃ according to the aforementioned leakage current test method, and the other sample was placed in a constant temperature chamber at 125℃ for 30 minutes and then immediately tested for leakage current under the same conditions. The high-temperature leakage current growth rate was calculated. The final results are shown in Table 1 below: Table 1 Performance Test Results As shown in Table 1, the high specific volume layered electrode foil obtained in this embodiment of the invention outperforms the comparative example in all aspects. The specific capacitance of Comparative Example 2 is much smaller than that of Example 1, which fully demonstrates the decisive contribution of the adsorption and dispersion synergistic effect of the corrosion modifier's corrosion inhibition system to suppress surface erosion and improve the effective specific surface area utilization. This indicates that the present invention, through the synergistic effect of modified acid mixture, corrosion modifier, and formation modifier, can synergistically and effectively improve the specific capacitance characteristics, pressure resistance, and high-temperature thermal stability of the electrode foil.
[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for manufacturing a high specific volume layered electrode foil, characterized in that, Includes the following steps: S1. Aluminum foil corrosion modification: High-purity aluminum foil is immersed in corrosion modifier for 10-20 minutes, and then removed to obtain corrosion-modified aluminum foil; S2. Aluminum foil formation modification: After cleaning the etched modified aluminum foil obtained in step S1 with deionized water, it is added to the formation modifier and the formation time is 60-90 minutes to obtain the formation modified aluminum foil. S3. Aluminum foil post-processing: Take out the chemically modified aluminum foil obtained in step S2, wash it with deionized water, and anneal it for 1-3 minutes to finally obtain a high specific volume layer electrode foil. The preparation of the corrosion modifier includes the following steps: S11. By weight, mix 50-65 parts of modified acid mixture with 20-40 parts of deionized water and stir at 100-200 r / min until the mixture is uniform. S12. Add 10-15 parts of ethylene glycol and 2-5 parts of polyethylene glycol-400 to the mixed solution obtained in step S11, and stir at a speed of 200-300 r / min for 10-15 min; S13. Add 1-3 parts of cerium ammonium nitrate to the mixed solution obtained in step S12, stir at 200-300 r / min until dissolved, and let stand for 20-30 min to remove bubbles to obtain the corrosion modifier.
2. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The preparation of the modified acid mixture includes the following steps: S111. By mass, 60-72 parts of hydrochloric acid solution with a mass concentration of 36-38% and 15-22 parts of sulfuric acid solution with a mass concentration of 98% are mixed evenly at 30-40℃ to obtain a first-grade acid solution; S112. Add 8-12 parts of 85% phosphoric acid solution and 3-6 parts of citric acid to the primary acid solution obtained in step S111, and stir at 300-400 r / min for 5-10 min to obtain the secondary acid solution. S113. Add 0.1-0.3 parts of nano silica sol and 2-5 parts of urea to the secondary acid solution obtained by S112, and stir at 400-500 r / min for 15-20 min to obtain the modified acid mixture.
3. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The preparation of the chemical modification agent includes the following steps: S21. By mass, 40-60 parts of deionized water, 15-25 parts of ammonium pentaborate, and 20-30 parts of ammonium adipate are stirred at 50-60°C until completely dissolved to obtain a primary chemical agent; S22. Add 0.5-1 parts of ammonium dihydrogen phosphate and 0.1-0.5 parts of ammonium hypophosphite to the primary forming agent obtained in step S21, and stir at a speed of 200-300 r / min for 10-15 min to obtain the secondary forming agent; S23. Add 0.05-0.2 parts of metatitanic acid and 3-8 parts of glycerol to the secondary forming agent obtained in step S22 under stirring at 45-50℃. After the addition is complete, continue stirring for 20-30 minutes. After filtration through a 0.45μm filter membrane, the forming modifier is obtained.
4. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The aluminum foil etching modification process in step S1 is carried out at a current density of 0.2-0.5 A / cm². 2 It is carried out in direct current.
5. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The immersion temperature during the aluminum foil corrosion modification process in step S1 is 60-80℃.
6. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The aluminum foil formation and modification process in step S2 is carried out at a current density of 0.3-0.5 A / cm². 2 The conversion is carried out under direct current, with a conversion voltage of 200-500V.
7. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The formation temperature for step S2, aluminum foil formation modification, is 80-90℃.
8. The method for manufacturing a high specific volume layered electrode foil according to claim 1, characterized in that, The annealing temperature in step S3 is 300-500℃.
9. A method for manufacturing a high specific volume layered electrode foil according to claim 3, characterized in that, The stirring speed in step S23 is 300-400 r / min.