Highly water-resistant electrode foil and method of making same

Abstract

The present disclosure provides a high hydration resistance electrode foil and a preparation method thereof. The preparation method comprises: multi-stage formation of the electrode foil with a formation solution added with an organic phosphorus compound; and preparation of a super-hydrophobic high-dielectric coating on the surface of the electrode foil. The preparation method of the high hydration resistance electrode foil provided by the present disclosure can improve the efficiency and compactness of the oxide film generated on the surface of the electrode foil, improve the hydration resistance, and facilitate obtaining an electrode foil with high hydration resistance and high capacity.

Description

Technical Field

[0001] This disclosure relates to the field of electrode foil preparation technology, and in particular to a method for preparing a highly hydration-resistant electrode foil and a highly hydration-resistant electrode foil. Background Technology

[0002] As new facilities and equipment place increasingly higher demands on miniaturization, lightweighting, and reliability, especially in electronic products such as laptops, drones, and wearable devices where internal space is extremely valuable, miniaturized capacitors are required, which places higher demands on the capacitance of electrode foils. At the same time, in high-end fields such as automotive electronics, aerospace, and medical devices, aluminum electrolytic capacitors need to operate stably for extended periods under extreme climates and high humidity, and the cost of failure is extremely high.

[0003] Therefore, continuously improving the hydration resistance and capacity of electrode foils for aluminum electrolytic capacitors has become an urgent problem to be solved. Summary of the Invention

[0004] This disclosure provides a method for preparing a highly hydration-resistant electrode foil and a highly hydration-resistant electrode foil.

[0005] In a first aspect, embodiments of this disclosure provide a method for preparing a highly hydration-resistant electrode foil, comprising: performing multi-stage formation on the electrode foil using a formation solution containing added organophosphorus compounds; and forming a superhydrophobic high-dielectric coating on the surface of the electrode foil.

[0006] In some embodiments, the organophosphorus compound includes cyclohexanehexaphosphate.

[0007] In some embodiments, when the electrode foil is subjected to multi-stage formation, the concentration of cyclohexanehexaphosphate in the formation solution is 0.1 to 1 wt%.

[0008] In some embodiments, the electrode foil is subjected to five-stage formation, wherein the concentration of cyclohexanehexyl hexaphosphate in the formation solution is greater in the first two stages of formation than in the last three stages of formation.

[0009] In some embodiments, the electrode foil is subjected to multi-stage formation using a formation solution containing cyclohexanehexyl hexaphosphate, comprising: placing the electrode foil in a formation solution composed of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexyl hexaphosphate, and performing the formation at 70–90°C and a current density of 10–20 mA / cm². 2The electrode foil was subjected to a first-stage formation at 190V for 10–20 minutes, followed by rinsing with water. The first-stage formed electrode foil was then placed in a formation solution composed of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexaphosphate, and the formation was carried out at 70–90℃ and a current density of 10–20 mA / cm². 2 Two-stage formation is performed at 380V for 10–20 minutes, followed by rinsing with water. The electrode foil after two-stage formation is then placed in a formation solution composed of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the reaction is carried out at 80–95℃ and a current density of 10–20 mA / cm². 2 Three-stage formation is performed at a voltage of 560V for 8–15 minutes, followed by rinsing with water. The electrode foil that has undergone three-stage formation is then placed in a formation solution composed of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the reaction is carried out at 80–95℃ and a current density of 10–20 mA / cm². 2 The electrode foil was subjected to a four-stage formation process at 620V for 20–30 minutes, followed by rinsing with water. The formed electrode foil was then placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the process was carried out at 80–95℃ and a current density of 10–20 mA / cm². 2 Perform five-stage formation at a voltage of 630V for 20-30 minutes, then remove and rinse with water.

[0010] In some embodiments, the superhydrophobic high-dielectric coating is made of a superhydrophobic high-dielectric material based on carboxymethyl cellulose and silica nanoparticles.

[0011] In some embodiments, a superhydrophobic high-dielectric coating is formed on the surface of the electrode foil, comprising: dissolving 5-10g of carboxymethyl cellulose in 100ml of deionized water, stirring for 10 minutes at a speed of 300r / min and a temperature of 70°C to obtain a carboxymethyl cellulose binder; dissolving 0.5-1g of nano-silica in 50ml of ethanol, performing ultrasonic dispersion treatment for 15-20 minutes, and homogenizing treatment using a high-speed homogenizer for 5-10 minutes to obtain a nano-silica slurry; mixing the carboxymethyl cellulose binder with the nano-silica slurry, adding 1-5ml of hexadecyltrimethoxysilane, stirring for 30 minutes at a speed of 850r / min and a temperature of 70°C to obtain a superhydrophobic high-dielectric material based on silica nanoparticles of carboxymethyl cellulose; uniformly coating the superhydrophobic high-dielectric material based on silica nanoparticles of carboxymethyl cellulose on the surface of the electrode foil, and drying for 30 minutes at a temperature of 100-200°C.

[0012] In some embodiments, before performing multi-stage formation of the electrode foil with a formation solution containing organophosphorus compounds, the method further includes: boiling the electrode foil in water at a temperature of 90–98°C for 8–10 min; rinsing with deionized water and draining.

[0013] In some embodiments, after performing multi-stage formation of the electrode foil using a formation solution containing organophosphorus compounds, the method further includes: placing the multi-stage formed electrode foil in a 5-10 wt% phosphoric acid solution at a temperature controlled at 50-80°C for 5-10 min, then removing and rinsing with water; placing the electrode foil in a solution composed of 10-12 wt% boric acid and 1-1.5 wt% ammonium pentaborate at 80-95°C and a current density of 10-20 mA / cm². 2 The subsequent formation is performed under a voltage of 650V for 5–10 minutes, followed by rinsing with water. The electrode foil is then placed in an oven at 400–550℃ for 3–5 minutes. Finally, the electrode foil is immersed in a solution of 4–15 wt% boric acid and 0.1–1 wt% ammonium pentaborate at 80–95℃ and a current density of 10–20 mA / cm². 2 The electrode foil is subjected to post-formation at a voltage of 650V for 5-10 minutes, then removed and rinsed with water. The electrode foil is then immersed in a 1-5 wt% ammonium dihydrogen phosphate solution at 60-80℃ for 5-10 minutes, removed, rinsed with water, and dried.

[0014] Secondly, embodiments of this disclosure provide a highly hydration-resistant electrode foil, which is prepared according to the preparation method of the highly hydration-resistant electrode foil described in the first aspect of this disclosure.

[0015] In this embodiment, the electrode foil is subjected to multi-stage formation using a formation solution containing organophosphorus compounds, which can improve the efficiency and density of oxide film formation on the electrode foil surface, and at the same time generate an aluminum phosphate film to improve hydration resistance. After formation, a superhydrophobic high-dielectric coating is made on the surface of the electrode foil, which can further improve the hydration resistance of the electrode foil, thereby obtaining an electrode foil with high hydration resistance and high capacity. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for preparing a highly hydration-resistant electrode foil according to an embodiment of this disclosure. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the technical solutions of this disclosure will be described in detail below with reference to the accompanying drawings.

[0018] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0019] Where there is no conflict, the various embodiments of this disclosure and the features thereof in the embodiments may be combined with each other.

[0020] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0022] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0023] Firstly, referring to Figure 1This disclosure provides a method for preparing a highly hydration-resistant electrode foil, comprising:

[0024] S1. The electrode foil is subjected to multi-stage formation using a formation solution containing organophosphorus compounds;

[0025] S2. A superhydrophobic high-dielectric coating is formed on the surface of the electrode foil.

[0026] In the embodiments of this disclosure, organophosphorus compounds have strong chelating ability. When performing multi-stage formation on electrode foil, they can promote the precipitation of aluminum ions, thereby accelerating the combination of chloride ions and aluminum ions, increasing the reaction rate, reducing micro-defects generated during the oxide film formation process, which is conducive to promoting the formation of highly crystalline anodic oxide films, reducing the thickness and formation constant of the oxide film, thereby mitigating the degree of blockage of fine corrosion tunnel micropores, which is conducive to the expansion effect and promotes the increase of oxide film specific volume.

[0027] In addition, organophosphorus compounds contain phosphate groups. During the formation of the oxide film, some aluminum ions react with phosphate groups to form an aluminum phosphate film, which helps to reduce the contact between the oxide film and water and improve the hydration resistance of the electrode foil. Phosphate groups can also remove undesirable oxide films on the surface during the oxide film formation process, ensuring the quality of the oxide film, reducing the thickness of undesirable oxide films, and thus improving the capacity of the electrode foil.

[0028] In the embodiments of this disclosure, a superhydrophobic high-dielectric coating is formed on the surface of the electrode foil, which can further improve the hydration resistance of the electrode foil.

[0029] This disclosure does not specifically limit the types of organophosphorus compounds. For example, organophosphorus compounds include adenosine triphosphate, glucose-6-phosphate, etc.

[0030] In some embodiments, the organophosphorus compound includes cyclohexanehexaphosphate.

[0031] In some embodiments, when the electrode foil is subjected to multi-stage formation, the concentration of cyclohexanehexaphosphate in the formation solution is 0.1 to 1 wt%.

[0032] In some embodiments, the electrode foil is subjected to five-stage formation, wherein the concentration of cyclohexanehexyl hexaphosphate in the formation solution is greater in the first two stages of formation than in the last three stages of formation.

[0033] In the embodiments of this disclosure, during the first two stages of formation, the oxide film is mainly formed on the basis of the water-boiling film. The use of a higher concentration of cyclohexanehexaphosphate is beneficial to the formation of a high-quality oxide film, which can significantly improve the hydration resistance, optimize the dielectric properties, increase the capacity of the electrode foil, and also improve the formation efficiency. During the latter three stages of formation, the oxide film is mainly formed on the electrochemically generated oxide film. The use of a lower concentration of cyclohexanehexaphosphate can prevent the oxide film from being damaged and ensure the withstand voltage capability of the electrode foil.

[0034] In some embodiments, the electrode foil is subjected to multi-stage formation using a formation solution containing cyclohexanehexyl hexaphosphate, comprising: placing the electrode foil in a formation solution composed of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexyl hexaphosphate, and performing the formation at 70–90°C and a current density of 10–20 mA / cm². 2 The electrode foil was subjected to a first-stage formation at 190V for 10–20 minutes, followed by rinsing with water. The first-stage formed electrode foil was then placed in a formation solution composed of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexaphosphate, and the formation was carried out at 70–90℃ and a current density of 10–20 mA / cm². 2 Two-stage formation is performed at 380V for 10–20 minutes, followed by rinsing with water. The electrode foil after two-stage formation is then placed in a formation solution composed of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the reaction is carried out at 80–95℃ and a current density of 10–20 mA / cm². 2 Three-stage formation is performed at a voltage of 560V for 8–15 minutes, followed by rinsing with water. The electrode foil that has undergone three-stage formation is then placed in a formation solution composed of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the reaction is carried out at 80–95℃ and a current density of 10–20 mA / cm². 2 The electrode foil was subjected to a four-stage formation process at 620V for 20–30 minutes, followed by rinsing with water. The formed electrode foil was then placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the process was carried out at 80–95℃ and a current density of 10–20 mA / cm². 2 Perform five-stage formation at a voltage of 630V for 20-30 minutes, then remove and rinse with water.

[0035] This disclosure does not impose any special limitations on the materials used for the superhydrophobic high-dielectric coating. For example, the superhydrophobic high-dielectric coating can be made of superhydrophobic high-dielectric materials such as polyimide and barium strontium titanate.

[0036] In some embodiments, the superhydrophobic high-dielectric coating is made of a superhydrophobic high-dielectric material based on carboxymethyl cellulose and silica nanoparticles.

[0037] In some embodiments, a superhydrophobic high-dielectric coating is formed on the surface of the electrode foil, comprising: dissolving 5-10g of carboxymethyl cellulose in 100ml of deionized water, stirring for 10 minutes at a speed of 300r / min and a temperature of 70°C to obtain a carboxymethyl cellulose binder; dissolving 0.5-1g of nano-silica in 50ml of ethanol, performing ultrasonic dispersion treatment for 15-20 minutes, and homogenizing treatment using a high-speed homogenizer for 5-10 minutes to obtain a nano-silica slurry; mixing the carboxymethyl cellulose binder with the nano-silica slurry, adding 1-5ml of hexadecyltrimethoxysilane, stirring for 30 minutes at a speed of 850r / min and a temperature of 70°C to obtain a superhydrophobic high-dielectric material based on silica nanoparticles of carboxymethyl cellulose; uniformly coating the superhydrophobic high-dielectric material based on silica nanoparticles of carboxymethyl cellulose on the surface of the electrode foil, and drying for 30 minutes at a temperature of 100-200°C.

[0038] In some embodiments, before performing multi-stage formation of the electrode foil with a formation solution containing organophosphorus compounds, the method further includes: boiling the electrode foil in water at a temperature of 90–98°C for 8–10 min; rinsing with deionized water and draining.

[0039] In some embodiments, after performing multi-stage formation of the electrode foil using a formation solution containing organophosphorus compounds, the method further includes: placing the multi-stage formed electrode foil in a 5-10 wt% phosphoric acid solution at a temperature controlled at 50-80°C for 5-10 min, then removing and rinsing with water; placing the electrode foil in a solution composed of 10-12 wt% boric acid and 1-1.5 wt% ammonium pentaborate at 80-95°C and a current density of 10-20 mA / cm². 2 The subsequent formation is performed under a voltage of 650V for 5–10 minutes, followed by rinsing with water. The electrode foil is then placed in an oven at 400–550℃ for 3–5 minutes. Finally, the electrode foil is immersed in a solution of 4–15 wt% boric acid and 0.1–1 wt% ammonium pentaborate at 80–95℃ and a current density of 10–20 mA / cm². 2The electrode foil is subjected to post-formation at a voltage of 650V for 5-10 minutes, then removed and rinsed with water. The electrode foil is then immersed in a 1-5 wt% ammonium dihydrogen phosphate solution at 60-80℃ for 5-10 minutes, removed, rinsed with water, and dried.

[0040] In some embodiments, the method for preparing a highly hydration-resistant electrode foil includes the following steps:

[0041] The electrode foil is boiled in water at 90-98°C for 8-10 minutes.

[0042] Rinse with deionized water and drain.

[0043] The electrode foil was placed in a forming solution composed of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexaphosphate, and subjected to a current density of 10–20 mA / cm at 70–90°C. 2 Perform primary formation at 190V for 10-20 minutes, then remove and rinse with water.

[0044] The electrode foil, after primary formation, was placed in a formation solution consisting of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexaphosphate, and subjected to a current density of 10–20 mA / cm at 70–90 °C. 2 Perform two-stage formation at 380V for 10-20 minutes, then remove and rinse with water.

[0045] The electrode foil, after secondary formation, was placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and subjected to a current density of 10–20 mA / cm at 80–95 °C. 2 Three-stage formation is performed under a voltage of 560V for 8-15 minutes, followed by rinsing with water.

[0046] The electrode foil, after undergoing three-stage formation, was placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the solution was applied at 80–95°C and a current density of 10–20 mA / cm². 2 Perform four-stage formation at a voltage of 620V for 20-30 minutes, then remove and rinse with water.

[0047] The electrode foil, after undergoing four stages of formation, was placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the solution was applied at 80–95°C and a current density of 10–20 mA / cm². 2 Perform five-stage formation at a voltage of 630V for 20-30 minutes, then remove and rinse with water.

[0048] The electrode foil that has undergone five-stage formation is placed in a 5-10 wt% phosphoric acid solution, the temperature is controlled at 50-80℃, the time is controlled at 5-10 min, and then it is taken out and washed with water.

[0049] The electrode foil was placed in a solution consisting of 10–12 wt% boric acid and 1–1.5 wt% ammonium pentaborate, and subjected to a current density of 10–20 mA / cm at 80–95°C. 2 The next formation is carried out under a voltage of 650V for 5-10 minutes, and then the product is removed and rinsed with water.

[0050] The electrode foil is placed in an oven, with the temperature controlled at 400-550℃ and the time controlled at 3-5 minutes.

[0051] The electrode foil was placed in a solution composed of 4–15 wt% boric acid and 0.1–1 wt% ammonium pentaborate, and subjected to a current density of 10–20 mA / cm at 80–95°C. 2 The secondary formation was carried out under a voltage of 650V for 5-10 minutes, and then the product was removed and rinsed with water.

[0052] The electrode foil is placed in a 1-5 wt% ammonium dihydrogen phosphate solution and immersed at 60-80°C for 5-10 minutes. It is then removed, washed with water, and dried.

[0053] Dissolve 5-10g of carboxymethyl cellulose in 100ml of deionized water, stir for 10 minutes at 300r / min and 70℃ to obtain carboxymethyl cellulose binder;

[0054] Dissolve 0.5–1 g of nano-silica in 50 ml of ethanol and perform ultrasonic dispersion treatment for 15–20 min. Then perform homogenization treatment for 5–10 min using a high-speed homogenizer to obtain nano-silica slurry.

[0055] The carboxymethyl cellulose binder was mixed with the nano-silica slurry, and 1-5 ml of hexadecyltrimethoxysilane was added. The mixture was stirred for 30 minutes at a speed of 850 r / min and a temperature of 70°C to obtain a superhydrophobic high dielectric material based on carboxymethyl cellulose and silica nanoparticles.

[0056] The superhydrophobic high dielectric material based on silica nanoparticles and carboxymethyl cellulose was uniformly coated on the surface of the electrode foil and dried for 30 minutes at a temperature of 100-200°C to obtain a highly hydration-resistant electrode foil.

[0057] Secondly, embodiments of this disclosure provide a highly hydration-resistant electrode foil, which is prepared according to the preparation method of the highly hydration-resistant electrode foil described in the first aspect of this disclosure.

[0058] Example

[0059] In this embodiment, the method for preparing the highly hydration-resistant electrode foil includes the following steps:

[0060] A thickness of 130 μm and a standard specific volume of 0.833 μF / cm² were used. 2 The electrode foil was boiled in water at 98°C for 10 minutes;

[0061] Rinse with deionized water and drain.

[0062] The electrode foil was placed in a formation solution consisting of 6 wt% boric acid, 1.2 wt% ammonium citrate, and 0.6 wt% cyclohexanehexaphosphate, and subjected to a current density of 15 mA / cm at 90°C. 2 Perform primary formation at 190V for 20 minutes, then remove and rinse with water.

[0063] The electrode foil, after primary formation, was placed in a formation solution consisting of 6 wt% boric acid, 1.2 wt% ammonium citrate, and 0.6 wt% cyclohexanehexaphosphate, and subjected to a current density of 15 mA / cm at 90 °C. 2 Two-stage formation is performed at a voltage of 380V for 20 minutes, followed by rinsing with water.

[0064] The electrode foil, after secondary formation, was placed in a formation solution consisting of 9.5 wt% boric acid, 0.5 wt% ammonium pentaborate, and 0.3 wt% cyclohexanehexaphosphate, and subjected to a current density of 15 mA / cm at 95 °C. 2 Three-stage formation is performed under a voltage of 560V for 15 minutes, followed by rinsing with water.

[0065] The electrode foil, which has undergone three-stage formation, was placed in a formation solution consisting of 9.5 wt% boric acid, 0.5 wt% ammonium pentaborate, and 0.3 wt% cyclohexanehexaphosphate. The reaction was carried out at 95°C and a current density of 15 mA / cm². 2 Perform four-stage formation at a voltage of 620V for 30 minutes, then remove and rinse with water.

[0066] The electrode foil, which had undergone four stages of formation, was placed in a formation solution consisting of 9.5 wt% boric acid, 0.5 wt% ammonium pentaborate, and 0.3 wt% cyclohexanehexaphosphate. The reaction was carried out at 95°C and a current density of 15 mA / cm². 2 Perform five-stage formation at a voltage of 630V for 30 minutes, then remove and rinse with water.

[0067] The electrode foil that has undergone five-stage formation was placed in a 7.5 wt% phosphoric acid solution, the temperature was controlled at 80℃ and the time was controlled at 10 min, and then it was taken out and washed with water.

[0068] The electrode foil was placed in a solution consisting of 11 wt% boric acid and 1.2 wt% ammonium pentaborate, and subjected to an electric current of 15 mA / cm at 95°C. 2 The next formation is carried out under a voltage of 650V for 10 minutes, and then the product is removed and rinsed with water.

[0069] The electrode foil was placed in an oven at 550°C for 5 minutes.

[0070] The electrode foil was placed in a solution consisting of 9.5 wt% boric acid and 0.5 wt% ammonium pentaborate, and subjected to a current density of 15 mA / cm at 95°C. 2 The post-formation was carried out under a voltage of 650V for 10 minutes, and then the product was removed and rinsed with water.

[0071] The electrode foil was placed in a 3 wt% ammonium dihydrogen phosphate solution and immersed at 80°C for 10 min. It was then removed, washed with water, and dried.

[0072] Dissolve 7.5 g of carboxymethyl cellulose in 100 ml of deionized water, stir for 10 minutes at a speed of 300 r / min and a temperature of 70 °C to obtain carboxymethyl cellulose binder;

[0073] 7.5g of nano-silica was dissolved in 50ml of ethanol and ultrasonically dispersed for 20min. Then, it was homogenized for 10min using a high-speed homogenizer to obtain nano-silica slurry.

[0074] The carboxymethyl cellulose binder was mixed with the nano-silica slurry, 3 ml of hexadecyltrimethoxysilane was added, and the mixture was stirred for 30 minutes at a speed of 850 r / min and a temperature of 70℃ to obtain a superhydrophobic high dielectric material based on carboxymethyl cellulose and silica nanoparticles.

[0075] The superhydrophobic high dielectric material based on silica nanoparticles and carboxymethyl cellulose was uniformly coated on the surface of the electrode foil and dried for 30 minutes at a temperature of 200°C to obtain a highly hydration-resistant electrode foil.

[0076] Comparative Example

[0077] The difference between the comparative example and the embodiment is that, in the comparative example, cyclohexanehexaphosphate was not added to the forming solution during the multi-stage forming of the electrode foil, and a superhydrophobic high dielectric material coating based on silica nanoparticles of carboxymethyl cellulose was not formed on the surface of the electrode foil.

[0078] Repeated experiments were conducted according to the examples, and comparative experiments were conducted according to the comparative examples. The performance of the electrode foils prepared in the examples and comparative examples was tested, and the results are shown in Table 1.

[0079] Table 1

[0080]

[0081] As can be seen from the data in Table 1, the embodiments exhibit higher withstand voltage, larger specific volume, shorter pressurization time, and higher hydration resistance compared to the comparative examples. This indicates that the method for preparing high-hydration electrode foil provided in this disclosure can improve the efficiency and density of oxide film formation on the electrode foil surface, thereby enhancing hydration resistance and facilitating the production of electrode foils with high hydration resistance and high capacity.

[0082] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in connection with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure as set forth by the appended claims.

Claims

1. A method for preparing a highly hydration-resistant electrode foil, comprising: The electrode foil is subjected to multi-stage formation using a formation solution containing organophosphorus compounds; A superhydrophobic high-dielectric coating is formed on the surface of the electrode foil; The organophosphorus compound includes cyclohexanehexyl hexaphosphate. The electrode foil is subjected to five-stage formation, and the concentration of cyclohexanehexyl hexaphosphate in the formation solution is 0.1-1 wt%. The concentration of cyclohexanehexyl hexaphosphate in the formation solution is greater in the first two stages of formation than in the last three stages.

2. The preparation method according to claim 1, wherein, The electrode foil is subjected to multi-stage formation using a formation solution containing cyclohexanehexaphosphate, including: The electrode foil was placed in a forming solution composed of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexaphosphate, and subjected to a current density of 10–20 mA / cm at 70–90°C. 2 Perform primary formation at 190V for 10-20 minutes, then remove and rinse with water. The electrode foil, after primary formation, was placed in a formation solution consisting of 2–10 wt% boric acid, 0.5–2 wt% ammonium citrate, and 0.2–1 wt% cyclohexanehexaphosphate, and the solution was applied at 70–90 °C and a current density of 10–20 mA / cm². 2 Perform two-stage formation at 380V for 10-20 minutes, then remove and rinse with water. The electrode foil, after secondary formation, was placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the solution was applied at 80–95 °C and a current density of 10–20 mA / cm². 2 Three-stage formation is performed under a voltage of 560V for 8-15 minutes, followed by rinsing with water. The electrode foil, after undergoing three-stage formation, was placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the solution was applied at 80–95 °C and a current density of 10–20 mA / cm². 2 Perform four-stage formation at a voltage of 620V for 20-30 minutes, then remove and rinse with water. The electrode foil, after undergoing four stages of formation, was placed in a formation solution consisting of 4–15 wt% boric acid, 0.1–1 wt% ammonium pentaborate, and 0.1–0.5 wt% cyclohexanehexaphosphate, and the solution was applied at 80–95 °C and a current density of 10–20 mA / cm². 2 Perform five-stage formation at a voltage of 630V for 20-30 minutes, then remove and rinse with water.

3. The preparation method according to claim 1 or 2, wherein, The superhydrophobic high-dielectric coating is made of a superhydrophobic high-dielectric material based on carboxymethyl cellulose and silica nanoparticles.

4. The preparation method according to claim 3, wherein, Fabricating a superhydrophobic, high-dielectric coating on the surface of the electrode foil includes: Dissolve 5-10g of carboxymethyl cellulose in 100ml of deionized water, stir for 10 minutes at 300r / min and 70℃ to obtain carboxymethyl cellulose binder; Dissolve 0.5–1 g of nano-silica in 50 ml of ethanol and perform ultrasonic dispersion treatment for 15–20 min. Then perform homogenization treatment for 5–10 min using a high-speed homogenizer to obtain nano-silica slurry. The carboxymethyl cellulose binder was mixed with the nano-silica slurry, and 1-5 ml of hexadecyltrimethoxysilane was added. The mixture was stirred for 30 minutes at a speed of 850 r / min and a temperature of 70°C to obtain a superhydrophobic high dielectric material based on carboxymethyl cellulose and silica nanoparticles. The superhydrophobic high dielectric material based on silica nanoparticles and carboxymethyl cellulose was uniformly coated on the surface of the electrode foil and dried for 30 minutes at a temperature of 100–200°C.

5. The preparation method according to claim 1 or 2, wherein, Before performing multi-stage formation of the electrode foil using a formation solution containing organophosphorus compounds, the process also includes: The electrode foil is boiled in water at 90-98°C for 8-10 minutes. Rinse with deionized water and drain.

6. The preparation method according to claim 5, wherein, After performing multi-stage formation of the electrode foil using a forming solution containing organophosphorus compounds, the process also includes: The electrode foil that has undergone multi-stage formation is placed in a 5-10 wt% phosphoric acid solution, the temperature is controlled at 50-80℃, the time is controlled at 5-10 min, and then it is taken out and washed with water. The electrode foil was placed in a solution consisting of 10–12 wt% boric acid and 1–1.5 wt% ammonium pentaborate, and subjected to a current density of 10–20 mA / cm at 80–95°C. 2 The next formation is carried out under a voltage of 650V for 5-10 minutes, and then the product is removed and rinsed with water. The electrode foil is placed in an oven, with the temperature controlled at 400-550℃ and the time controlled at 3-5 minutes. The electrode foil was placed in a solution composed of 4–15 wt% boric acid and 0.1–1 wt% ammonium pentaborate, and subjected to a current density of 10–20 mA / cm at 80–95°C. 2 The secondary formation was carried out under a voltage of 650V for 5-10 minutes, and then the product was removed and rinsed with water. The electrode foil is placed in a 1-5 wt% ammonium dihydrogen phosphate solution and immersed at 60-80°C for 5-10 minutes. It is then removed, washed with water, and dried.

7. A highly hydration-resistant electrode foil, wherein the highly hydration-resistant electrode foil is prepared by the method for preparing a highly hydration-resistant electrode foil according to any one of claims 1 to 6.

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