Electrochemical current collector and its preparation method and application

Abstract

The present invention belongs to the field of electrochemical technology, and specifically relates to an electrochemical current collector and its preparation method and application. The preparation method includes the following steps: pre-treatment, using a weak acid degreasing solution and an anti-over-degreasing passivation solution to pre-treat the aluminum foil; perforation, using multiple electrochemical corrosion and chemical corrosion alternately to corrode the aluminum foil after pre-treatment; post-treatment, using zinc sulfate solution and a phosphorus salt solution to perform initial post-treatment on the aluminum foil after corrosion, and then using an ammonia salt solution to perform electrical post-treatment on the aluminum foil after the initial post-treatment to form an oxide protective film. The preparation method of the electrochemical current collector provided by the present invention can enable slurry formulas of different processes to be effectively filled into the etched holes, forming a stable electrode structure, ensuring the efficient transmission of electrons and ions, and thus effectively extending the service life of the supercapacitor.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical technology, and in particular relates to an electrochemical current collector and a preparation method and application thereof. Background Art

[0002] The current collector is a key component in supercapacitors for conducting current. If the adhesion between the current collector and the active material is poor, the active material will easily fall off, which will in turn increase the internal resistance of the supercapacitor, cause uneven current conduction, and ultimately lead to unstable supercapacitor performance. Moreover, as the number of charge and discharge cycles increases, the active material on the poorly adhered current collector will fall off more severely, which will reduce the effective reaction area of ​​the supercapacitor, causing the supercapacitor's capacity to decay faster, thereby shortening the supercapacitor's service life. Therefore, the surface properties of the current collector have a significant impact on the production and performance of supercapacitors.

[0003] A good combination of the current collector pores and the slurry is one of the key factors in improving the performance of supercapacitors. A reasonable current collector pore structure can promote the uniform deposition of active materials in the slurry, enhance the electrochemical reaction area, and thus improve the capacity and cycle stability of the supercapacitor. In the existing technology, due to defects in the preparation technology of the current collector, it is easy to cause asymmetric structures on both sides and asymmetric contact resistances of the coatings on both sides, which in turn makes it impossible to release the capacity of the electrodes on both sides evenly; at the same time, the asymmetry of the two sides will also cause inconsistent coating bonding strength, resulting in a serious imbalance in the charge and discharge cycle life of the two sides, thereby accelerating the attenuation of the supercapacitor capacity. In addition, aluminum foil is basically rolled from aluminum ingots with a larger thickness. During the rolling process, the contact between the aluminum ingot and the roller needs to be controlled, so lubricants are generally added to the surface of the aluminum foil to protect the aluminum ingot and the roller. Therefore, the surface lubricant will also have a certain impact on the supercapacitor, and the surface of the aluminum foil needs to be delubricated.

[0004] In summary, studying a technology that can effectively improve the adhesion between the active material and the supercapacitor, reduce the internal resistance of the supercapacitor, and improve the energy transmission efficiency and the stability of the supercapacitor performance has far-reaching significance for extending the service life of the supercapacitor and promoting the development of the supercapacitor industry. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the first aspect of the present application is to provide a method for preparing an electrochemical current collector. First, a weak acid degreasing solution and an anti-over-degreasing passivation solution are used to degrease the aluminum foil to improve the uniformity of the surface energy of the aluminum foil. Then, through multi-level electrochemical etching holes, slurry formulas of different processes can be effectively filled into the etched holes, forming a stable electrode structure to ensure efficient transmission of electrons and ions. In addition, the later process forms a film protective layer on the surface of the electrochemical current collector, so that the electrochemical current collector can remain stable in various harsh environments. This fine interface regulation can provide a solid foundation for the development of high-performance supercapacitors.

[0006] The second aspect of the present application aims to provide an electrochemical current collector prepared using the above-mentioned electrochemical current collector preparation method, which can effectively improve the adhesion between the active material and the supercapacitor, reduce the internal resistance of the supercapacitor, improve the energy transmission efficiency and the performance stability of the supercapacitor, and thereby effectively extend the service life of the supercapacitor.

[0007] The third aspect of the present application aims to provide an electrochemical current collector and its preparation method.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] The method for preparing the electrochemical current collector of the present invention comprises the following steps:

[0010] Pretreatment: using weak acid degreasing solution and anti-over-degreasing passivation solution to pretreat the aluminum foil;

[0011] Hole arrangement: multiple electrochemical etching and chemical etching are performed alternately to etch and pierce the aluminum foil after pretreatment;

[0012] Post-treatment: After the aluminum foil is corroded and pierced with holes, it is post-treated with zinc sulfate solution and phosphorus salt solution, and then the aluminum foil is subjected to electrical post-treatment with ammonia salt solution to form an oxide protective film; wherein,

[0013] The hole arrangement step includes the following steps:

[0014] Primary electrochemical corrosion: using chloride ion etching solution to electrochemically corrode the pre-treated aluminum foil;

[0015] Primary chemical etching, using phosphoric acid solution to chemically etch the aluminum foil after the primary electrochemical etching treatment;

[0016] Secondary electrochemical corrosion: using a mixture of hydrochloric acid solution and zinc sulfate solution, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion is subjected to electrochemical corrosion again;

[0017] Secondary chemical etching uses phosphoric acid solution to chemically etch the aluminum foil after the second electrochemical etching treatment.

[0018] The third-level electrochemical etching uses a chlorine-containing etching solution to electrochemically etch the aluminum foil after two alternating electrochemical and chemical etching treatments.

[0019] Furthermore, in the primary electrochemical corrosion step, the chloride ion etching solution is a mixture of 1 mol / L-6 mol / L hydrochloric acid solution and 0.1 mol / L-1 mol / L phosphoric acid solution in a ratio of 1:1, the solution temperature is 35°C-45°C; the corrosion current is 0.1 A / cm 2 -1A / cm 2 , frequency is 45 Hz -70 Hz; corrosion time is 5s -12s.

[0020] Furthermore, in the primary chemical etching and the secondary chemical etching steps, the phosphoric acid solution is a phosphoric acid solution with a mass percentage concentration of 0.1%-3%, a solution temperature of 35° C.-55° C., and an etching time of 20s-60s.

[0021] Furthermore, in the secondary electrochemical corrosion step, the mixed solution is prepared by mixing 0.1 mol / L-2 mol / L hydrochloric acid solution and 0.1 mol / L-1 mol / L zinc sulfate solution in a ratio of 1:1, the solution temperature is 25°C-35°C; the corrosion current is 0.1 A / cm 2 -0.5A / cm 2 , frequency is 25 Hz -45 Hz; corrosion time is 5s -15s.

[0022] Furthermore, in the three-stage electrochemical etching step, the chlorine-containing etching solution is a 0.1 mol / L-1 mol / L chlorine-containing etching solution, which is a mixture of one or more of hydrochloric acid solution, potassium chloride solution, titanium tetrachloride solution, titanium trichloride solution or ammonium chloride solution; the solution temperature is 35°C-55°C; the corrosion current is 0.05 A / cm 2 -0.2A / cm 2 , frequency is 15 Hz-35 Hz, and corrosion time is 5s-20s.

[0023] Furthermore, in the post-treatment step, the zinc sulfate solution is a zinc sulfate solution with a mass percentage concentration of 0.1%-1%, the solution temperature is 35° C.-65° C., and the post-treatment time is 20s-65s.

[0024] Furthermore, in the post-treatment step, the phosphorus-containing salt solution is a phosphorus-containing salt solution with a mass percentage concentration of 0.1%-3%, which is a mixture of one or two of ammonium dihydrogen phosphate solution, diammonium hydrogen phosphate solution, and trisodium phosphate solution. The solution temperature is 35°C-70°C; and the post-treatment time is 20s-65s.

[0025] Furthermore, in the post-treatment step, the ammonia-containing salt solution is an ammonia-containing salt solution with a mass percentage concentration of 0.1%-3%, which is a mixture of one or more of ammonium adipate solution, diammonium hydrogen phosphate solution, and ammonium dihydrogen phosphate solution, and the solution temperature is 30°C-55°C; the post-treatment current is 2A, the voltage is 0.2V, and the post-treatment time is 5s-15s.

[0026] Furthermore, in the pretreatment step, the weak acid degreasing solution is prepared by mixing a citric acid solution with a mass percentage concentration of 0.1%-3% and an oxalic acid solution with a mass percentage concentration of 0.1%-3% in a ratio of 1:1, and the solution temperature is 35°C-55°C.

[0027] Furthermore, in the pretreatment step, the anti-over-oiling passivation liquid is a mixture of one or more of ammonium dihydrogen phosphate solution, sodium dihydrogen phosphate solution, disodium hydrogen phosphate solution, and trisodium phosphate solution, the mass percentage concentration of phosphorus salt is 0.1%-3%, and the solution temperature is 50°C-70°C.

[0028] Furthermore, the electrochemical current collector preparation method further includes the following steps:

[0029] Cleaning: Use a multi-stage water tank to clean the aluminum foil after post-processing;

[0030] Drying: The cleaned aluminum foil is dried in multiple stages at a temperature of 80°C-350°C;

[0031] Wherein, the drying step includes the following steps:

[0032] First-stage drying: drying the cleaned aluminum foil at a temperature of 80°C-200°C for 1-3 minutes;

[0033] Secondary drying: use a drying temperature of 200-350°C to dry the aluminum foil again after the primary drying, and the drying time is 2-3 minutes;

[0034] The third stage drying uses a drying temperature of 80℃-200℃ to dry the aluminum foil again after the second drying, and the drying time is 2min-3min.

[0035] The electrochemical current collector in the present invention is prepared by processing aluminum foil using the above-mentioned electrochemical current collector preparation method, and the thickness of the aluminum foil is 18 μm-30 μm.

[0036] In the present invention, the electrochemical current collector prepared by processing aluminum foil with a thickness of 18 μm-30 μm using the electrochemical current collector preparation method is used in supercapacitors.

[0037] Based on the above technical solution, the present invention has the following technical effects:

[0038] 1. The present invention provides a method for preparing an electrochemical current collector. First, a weak acid degreasing solution and an anti-over-degreasing passivation solution are used to degrease the aluminum foil to improve the uniformity of the surface energy of the aluminum foil. Subsequently, the aluminum foil is corroded and pierced by alternating multiple electrochemical etching and chemical etching processes, so that the holes on the surface of the aluminum foil are smaller and more fragmented, and the hole layer has more rivet structures, so that the slurry formulations of different processes can be effectively filled into the etched holes to form a stable electrode structure and ensure the efficient transmission of electrons and ions. Subsequently, the aluminum foil after pores is post-treated with a zinc sulfate solution and a phosphorus salt solution, and then the aluminum foil that has undergone preliminary post-treatment is electrified and post-treated with an ammonia salt solution, so that a film protective layer is formed on the surface of the electrochemical current collector, which can remain stable under various harsh environments. This fine interface regulation can provide a solid foundation for the development of high-performance supercapacitors.

[0039] 2. The electrochemical current collector provided by the present invention has a porous structure on its surface, which allows the slurry to flow into it quickly and is extremely difficult to peel out. This improves the adhesion between the slurry and the active material and reduces the internal resistance of the supercapacitor, thereby improving the energy transmission efficiency and the stability of the supercapacitor performance, thereby effectively extending the service life of the supercapacitor. In addition, the electrochemical current collector has excellent corrosion resistance and can remain stable in various harsh environments. It optimizes the interfacial reaction kinetics of the supercapacitor, thereby further improving the performance of the supercapacitor and extending the service life of the supercapacitor.

[0040] 3. The electrochemical current collector provided by the present invention and the electrochemical current collector prepared by the preparation method thereof can be applied to supercapacitors to increase the internal resistance of the supercapacitor, improve the energy transmission efficiency and performance stability, and extend the service life of the supercapacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the SEM image of the aluminum foil surface after primary electrochemical corrosion in Example 4.

[0042] Figure 2 This is an SEM image of the aluminum foil surface after secondary electrochemical corrosion in Example 4.

[0043] Figure 3 This is an SEM image of the aluminum foil surface after three-level electrochemical corrosion in Example 4.

[0044] Figure 4 This is an SEM image of the aluminum foil surface after only three-level electrochemical etching in Example 4. DETAILED DESCRIPTION

[0045] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to specific embodiments. The present invention provides preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0046] Before further describing the various embodiments of the compounds / compositions and methods of the present disclosure in more detail through exemplary descriptions, examples and results, it should be understood that the embodiments of the present disclosure are not limited in application to the details of the methods and compositions described in the following description. The description provided herein is for illustrative purposes only and is not to be interpreted in a limiting sense. The inventive concepts of the present disclosure are capable of other embodiments or can be practiced or implemented in various ways. Therefore, the language used herein is intended to give the broadest scope and meaning; and the embodiments are intended to be exemplary, not exhaustive, and are not intended to limit the present disclosure to these specific embodiments. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive unless otherwise stated. In addition, in the following detailed description, many specific details are listed in order to provide a more thorough understanding of the present disclosure.

[0047] However, it is obvious to one skilled in the art that the embodiments of the present disclosure can be practiced without these specific details. In other cases, features well known to one skilled in the art have not been described in detail to avoid unnecessary complexity of the description. It is intended that all alternatives, replacements, modifications and equivalents obvious to one skilled in the art are included within the scope of the present disclosure. Based on the present disclosure, all compounds / compositions disclosed herein and their preparation methods, applications and uses can be prepared and implemented without undue experimentation.

[0048] Thus, while the compounds / compositions and methods of the present disclosure have been described with respect to specific embodiments, it will be apparent to those skilled in the art that variations may be made in the formulations, compounds or compositions and / or methods, as well as in the steps or order of steps of the methods described herein, without departing from the spirit and scope of the inventive concepts of the present disclosure.

[0049] As used herein, any reference to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in multiple places in the specification are not necessarily all referring to the same embodiment.

[0050] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present disclosure shall have the meanings commonly understood by those of ordinary skill in the art. In addition, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0051] In a first aspect, the method for preparing an electrochemical current collector of the present invention comprises the following steps:

[0052] S10, pre-treatment, using a weak acid degreasing solution and an anti-over-greasing passivation liquid to pre-treat the aluminum foil; further, a multi-tank method is used to pre-treat the aluminum foil, because the oil content of aluminum foil produced by each manufacturer is different, and the oil pollution on the aluminum foil is also uneven, so after using a weak acid degreasing solution for degreasing, it is passivated with an anti-over-greasing passivation liquid to prevent excessive corrosion of the aluminum foil after local degreasing, thereby preventing uneven surface energy in various parts of the aluminum foil, resulting in uneven pore distribution after primary power-on.

[0053] The oil floating out of the pretreatment tank overflows from the upper part of the pretreatment tank, while the oil carried by the aluminum foil into the primary electrolytic tank through the pretreatment tank not only overflows from the upper part of the electrolytic tank, but also can be adsorbed by adding activated carbon strips. Preferably, in the pretreatment step, the weak acid degreasing solution is a mixture of a 0.1%-3% by weight citric acid solution and a 0.1%-3% by weight oxalic acid solution in a ratio of 1:1, and the solution temperature is 35°C-55°C. The passivation solution to prevent excessive degreasing is a mixture of one or more of ammonium dihydrogen phosphate solution, sodium dihydrogen phosphate solution, disodium hydrogen phosphate solution, and trisodium phosphate solution, containing a phosphorus salt with a mass percentage concentration of 0.1%-3%, and the solution temperature is 50°C-70°C.

[0054] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and arrange holes on the pre-treated aluminum foil; further, specifically including the following steps:

[0055] S21, primary electrochemical corrosion, using a chloride ion etching solution to electrochemically corrode the aluminum foil after pretreatment; preferably, the chloride ion etching solution is a mixture of 1 mol / L-6 mol / L hydrochloric acid solution and 0.1 mol / L-1 mol / L phosphoric acid solution in a ratio of 1:1, the solution temperature is 35°C-45°C; the corrosion current is 0.1 A / cm 2 -1A / cm 2The frequency is 45Hz-70Hz and the etching time is 5s-12s. This step uses a combination of high current, high frequency and high chloride ion concentration to create as large holes as possible on the aluminum foil surface.

[0056] S22, primary chemical etching, using a phosphoric acid solution to chemically etch the aluminum foil after the primary electrochemical etching. Preferably, the phosphoric acid solution has a mass concentration of 0.1% to 3%, a solution temperature of 35°C to 55°C, and an etching time of 20s to 60s. This step uses the phosphoric acid solution to dissolve some of the miscellaneous small holes on the non-main lines of the primary electrochemical etching, paving the way for subsequent secondary electrochemical etching holes.

[0057] S23, secondary electrochemical corrosion, using a mixture of hydrochloric acid solution and zinc sulfate solution to electrochemically corrode the aluminum foil after primary electrochemical corrosion and primary chemical corrosion; preferably, the mixture is composed of 0.1mol / L-2mol / L hydrochloric acid solution and 0.1mol / L-1mol / L zinc sulfate solution in a ratio of 1:1, the solution temperature is 25℃-35℃; the corrosion current is 0.1A / cm 2 -0.5A / cm 2 The frequency is 25 Hz - 45 Hz; the etching time is 5s - 15s. This step uses a combination of medium current, medium frequency, and medium chloride ions to allow the holes to be drilled deeper than the original holes, making them smaller and more fragmented.

[0058] S24: Secondary chemical etching: The aluminum foil, after the second electrochemical etching treatment, is subjected to a second chemical etching treatment using a phosphoric acid solution. Preferably, the phosphoric acid solution has a mass concentration of 0.1% to 3%, a solution temperature of 35°C to 55°C, and an etching time of 20s to 60s. This has the same purpose as step S22, but can dissolve some of the small holes on the non-main track of the second electrochemical etching, paving the way for the subsequent third electrochemical etching.

[0059] S25, three-stage electrochemical corrosion, using chlorine-containing etching solution to electrochemically etch the aluminum foil after two alternating electrochemical and chemical etching treatments; wherein the chlorine-containing etching solution is a 0.1mol / L-1mol / L chlorine-containing etching solution, which is a mixture of one or more of hydrochloric acid solution, potassium chloride solution, titanium tetrachloride solution, titanium trichloride solution or ammonium chloride solution; preferably, the chlorine-containing etching solution is a mixture of one or more of titanium tetrachloride solution and titanium trichloride solution. The solution temperature is 35℃-55℃; the corrosion current is 0.05 A / cm 2 -0.2A / cm 2The frequency is 15 Hz -35 Hz, and the etching time is 5s-20s. This step uses a weak titanate as an etching solution. Firstly, titanium and aluminum foil can form a more conductive Ti-Al alloy. Secondly, weak Cl ions can better punch random holes into the holes, making the inner layer of the holes more rivet-like. This improves the adhesion between the electrochemical current collector and the active material, thereby improving the energy transmission efficiency and the performance stability of the supercapacitor, and thus effectively extending the service life of the supercapacitor.

[0060] S30, post-treatment, after the aluminum foil with the corroded holes is initially post-treated with a zinc sulfate solution and a phosphorus salt solution, the aluminum foil after the initial post-treatment is then subjected to an electrical post-treatment with an ammonia salt solution to form an oxide protective film. Preferably, the zinc sulfate solution is a zinc sulfate solution with a mass percentage concentration of 0.1%-1%, the solution temperature is 35°C-65°C, and the post-treatment time is 20s-65s. The phosphorus salt solution is a phosphorus salt solution with a mass percentage concentration of 0.1%-3%, and is composed of one or two of ammonium dihydrogen phosphate solution, diammonium hydrogen phosphate solution, and trisodium phosphate solution. The solution temperature is 35°C-70°C; the post-treatment time is 20s-65s. The ammoniacal salt solution is a mixture of one or more of an ammonium adipate solution, a diammonium hydrogen phosphate solution, and a diammonium dihydrogen phosphate solution at a concentration of 0.1% to 3% by mass. The temperature of the solution is 30°C to 55°C. The post-treatment current is 2A, the voltage is 0.2V, and the post-treatment time is 5s to 15s. In this step, the aluminum foil after the holes are first post-treated with a zinc sulfate solution and a phosphorus salt solution. Then, the aluminum foil that has undergone preliminary post-treatment is subjected to an electrical post-treatment with an ammoniacal salt solution. This allows a protective film layer to form on the surface of the electrochemical current collector, which can remain stable in various harsh environments. This fine interface control can provide a solid foundation for the development of high-performance supercapacitors.

[0061] S40, cleaning, using a multi-stage water tank to clean the aluminum foil after post-processing; preferably, the multi-stage water tank is 3-6 water tanks, and there are two sets of scrapers on the water outlet tank to scrape off some water on the aluminum foil.

[0062] S50, drying, performing multi-stage drying on the cleaned aluminum foil at a drying temperature of 80°C-350°C; specifically comprising the following steps:

[0063] S51, primary drying, using a drying temperature of 80°C-200°C to dry the cleaned aluminum foil for 1 minute to 3 minutes;

[0064] S52, secondary drying, using a drying temperature of 200°C-350°C to dry the aluminum foil after the primary drying for 2 minutes to 3 minutes;

[0065] S53, three-stage drying, using a drying temperature of 80℃-200℃ to dry the aluminum foil after the second drying again, and the drying time is 2min-3min.

[0066] The drying step adopts a temperature change form from low to high and then from high to low, which can effectively ensure the uniformity and quality of the drying of the electrochemical current collector surface, thereby ensuring the quality of the electrochemical current collector preparation.

[0067] Aluminum foil with a thickness of 18 μm-30 μm can be used to prepare an electrochemical current collector using the above-mentioned electrochemical current collector preparation method, and can be used in supercapacitors.

[0068] Example 1:

[0069] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0070] S10: Pretreatment: Degreasing an 18 μm thick aluminum foil using a weak acid degreasing solution consisting of a 1.5% by mass citric acid solution and a 1.5% by mass oxalic acid solution in a 1:1 ratio at a solution temperature of 45°C. Then, anti-passivation treatment is performed on the aluminum foil using a 2% by mass ammonium dihydrogen phosphate solution containing a phosphorus salt at a solution temperature of 50°C.

[0071] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0072] S21, primary electrochemical corrosion, using a chloride ion etching solution made of a mixture of 2 mol / L hydrochloric acid solution and 0.8 mol / L phosphoric acid solution in a ratio of 1:1, with a solution temperature of 40 ° C and a corrosion current of 0.8 A / cm 2 The pre-treated aluminum foil was electrochemically corroded under the conditions of 55 Hz and a corrosion time of 5 s.

[0073] S22. Primary chemical etching: using a phosphoric acid solution with a mass percentage concentration of 1.5% at a solution temperature of 45° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 40 seconds.

[0074] S23, secondary electrochemical corrosion, using a mixture of 1.5 mol / L hydrochloric acid solution and 0.7 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 30 ° C and a corrosion current of 0.3 A / cm 2 Under the condition of a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to electrochemical corrosion again, and the corrosion time was 5 s.

[0075] S24, secondary chemical etching, using a phosphoric acid solution with a mass percentage concentration of 1.5%, at a solution temperature of 45°C, to chemically etch the aluminum foil after the second electrochemical etching treatment for 40 seconds.

[0076] S25, three-stage electrochemical corrosion, using a 0.5 mol / L chlorine-containing etching solution made from a mixture of potassium chloride solution and titanium tetrachloride solution, with a solution temperature of 45°C and a corrosion current of 0.1 A / cm 2 Under the condition of a frequency of 25 Hz, the aluminum foil, which has been treated alternately with two electrochemical corrosion and chemical corrosion treatments, is subjected to electrochemical corrosion treatment for 5 seconds.

[0077] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.5% at a solution temperature of 50°C to post-treat the aluminum foil after the holes are formed for 55 seconds;

[0078] Then, the aluminum foil after the primary post-treatment was subjected to a secondary post-treatment for 45 seconds using a phosphorus salt solution with a mass percentage concentration of 1.5% and a solution temperature of 50°C.

[0079] Then, the aluminum foil that had been post-treated twice was post-treated three times for 10 seconds using an ammoniacal salt solution with a mass percentage concentration of 1.5% prepared by mixing an ammonium adipate solution and a diammonium hydrogen phosphate solution at a solution temperature of 45°C, a current of 2A, and a voltage of 0.2V.

[0080] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0081] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0082] S51, primary drying, using a drying temperature of 150° C. to dry the cleaned aluminum foil for 3 minutes;

[0083] S52, secondary drying, using a drying temperature of 250° C. to dry the aluminum foil after the primary drying for a second time for 2 minutes;

[0084] S53, three-stage drying, using a drying temperature of 150° C. to dry the aluminum foil after the second drying for 2 minutes to obtain an electrochemical current collector.

[0085] Example 2:

[0086] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0087] S10: Pretreatment: Degreasing an 18 μm thick aluminum foil using a weak acid degreasing solution prepared by mixing a 3% by mass citric acid solution and a 3% by mass oxalic acid solution in a ratio of 1:1 at a solution temperature of 35°C. Then, an anti-over-degreasing passivation solution prepared by mixing a sodium dihydrogen phosphate solution and a trisodium phosphate solution and containing a 3% by mass phosphate salt was used to prevent passivation of the aluminum foil at a solution temperature of 70°C.

[0088] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0089] S21, primary electrochemical corrosion, using a chloride ion etching solution made of a mixture of 6 mol / L hydrochloric acid solution and 1 mol / L phosphoric acid solution in a ratio of 1:1, with a solution temperature of 35°C and a corrosion current of 1 A / cm 2 The aluminum foil after pretreatment was electrochemically corroded under the conditions of 70 Hz and a corrosion time of 5 s.

[0090] S22. Primary chemical etching: using a 3% by mass phosphoric acid solution at a solution temperature of 55° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 60 seconds.

[0091] S23, secondary electrochemical corrosion, using a mixture of 2 mol / L hydrochloric acid solution and 1 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 25 ° C and a corrosion current of 0.5 A / cm 2 Under the conditions of a frequency of 45 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to electrochemical corrosion again, and the corrosion time was 5 s.

[0092] S24, secondary chemical etching, using a 3% by mass phosphoric acid solution at a solution temperature of 55° C. to chemically etch the aluminum foil after the second electrochemical etching treatment for 60 seconds.

[0093] S25, three-stage electrochemical corrosion, using a 1 mol / L chlorine-containing etching solution made of a mixture of hydrochloric acid solution, potassium chloride solution, titanium trichloride solution and ammonium chloride solution, with a solution temperature of 35°C and a corrosion current of 0.2 A / cm 2 Under the condition of a frequency of 35 Hz, the aluminum foil, which has been treated alternately with two electrochemical corrosion and chemical corrosion treatments, is subjected to electrochemical corrosion treatment for 5 seconds.

[0094] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 1% at a solution temperature of 35°C to post-treat the aluminum foil after the holes are formed for 65 seconds;

[0095] Then, the aluminum foil was subjected to a secondary post-treatment for 65 seconds using a phosphorus salt solution with a mass percentage concentration of 3% and a solution temperature of 70°C, which was a mixture of ammonium dihydrogen phosphate solution and trisodium phosphate solution.

[0096] Then, the aluminum foil that had been post-treated twice was post-treated three times for 15 seconds using an ammoniacal salt solution with a mass percentage concentration of 3% prepared by mixing an ammonium adipate solution and a diammonium hydrogen phosphate solution at a solution temperature of 55°C, a current of 2A, and a voltage of 0.2V.

[0097] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0098] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0099] S51, primary drying, using a drying temperature of 200° C. to dry the cleaned aluminum foil for 1 minute;

[0100] S52, secondary drying, using a drying temperature of 350° C. to dry the aluminum foil after the primary drying for a second time for 3 minutes;

[0101] S53, three-stage drying, using a drying temperature of 200° C. to dry the aluminum foil after the second drying for 3 minutes to obtain an electrochemical current collector.

[0102] Example 3:

[0103] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0104] S10: Pretreatment: Degreasing the aluminum foil with a thickness of 20 μm using a weak acid degreasing solution prepared by mixing a 0.1% by mass citric acid solution with a 0.1% by mass oxalic acid solution at a ratio of 1:1 at a solution temperature of 55°C. Then, anti-passivation treatment was performed on the aluminum foil using a 0.1% by mass ammonium dihydrogen phosphate solution containing a phosphorus salt at a solution temperature of 70°C.

[0105] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0106] S21, primary electrochemical corrosion, using a chloride ion etching solution consisting of a 1 mol / L hydrochloric acid solution and a 0.1 mol / L phosphoric acid solution in a 1:1 ratio, with a solution temperature of 45 ° C and a corrosion current of 0.1 A / cm2 The aluminum foil after pretreatment was electrochemically corroded under the conditions of 45 Hz and a corrosion time of 7 s.

[0107] S22. Primary chemical etching: using a phosphoric acid solution with a mass percentage concentration of 0.1%, at a solution temperature of 35° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 20 seconds.

[0108] S23, secondary electrochemical corrosion, using a mixture of 0.1 mol / L hydrochloric acid solution and 0.1 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 35 ° C and a corrosion current of 0.1 A / cm 2 Under the conditions of 25 Hz and a frequency of 25 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to secondary electrochemical corrosion treatment, and the corrosion time was 7 s.

[0109] S24, secondary chemical etching, using a phosphoric acid solution with a mass percentage concentration of 0.1%, at a solution temperature of 35° C., to chemically etch the aluminum foil after the second electrochemical etching treatment for 20 seconds.

[0110] S25, three-stage electrochemical corrosion, using a mixture of hydrochloric acid solution and titanium trichloride solution, 0.1 mol / L chlorine-containing etching solution, with a solution temperature of 55 ° C and a corrosion current of 0.05 A / cm 2 Under the condition of 15 Hz frequency, the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments was subjected to electrochemical corrosion treatment for 7 s.

[0111] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.1% at a solution temperature of 65°C to post-treat the aluminum foil after the holes are formed for 20 seconds;

[0112] Then, the aluminum foil after the primary post-treatment was subjected to a secondary post-treatment for 20 seconds using a diammonium phosphate solution containing 0.1% of phosphorus salt by mass and at a solution temperature of 35°C.

[0113] Then, the aluminum foil that had been post-treated twice was post-treated three times for 5 seconds using an ammonium adipate solution containing 2% ammonium salt by mass at a solution temperature of 30° C., a current of 2 A, and a voltage of 0.2 V.

[0114] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0115] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0116] S51, primary drying, using a drying temperature of 80° C. to dry the cleaned aluminum foil for 3 minutes;

[0117] S52, secondary drying, using a drying temperature of 200 ° C, the aluminum foil after the primary drying is dried again, and the drying time is 3 minutes;

[0118] S53, three-stage drying, using a drying temperature of 80° C. to dry the aluminum foil after the second drying for 3 minutes to obtain an electrochemical current collector.

[0119] Example 4:

[0120] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0121] S10: Pretreatment: Degreasing the aluminum foil with a thickness of 20 μm using a weak acid degreasing solution prepared by mixing a 1% by mass citric acid solution and a 1% by mass oxalic acid solution in a ratio of 1:1 at a solution temperature of 45°C. Then, anti-passivation treatment is performed on the aluminum foil using a passivation solution prepared by mixing an ammonium dihydrogen phosphate solution and a sodium dihydrogen phosphate solution and containing a 1% by mass phosphate salt at a solution temperature of 50°C.

[0122] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0123] S21, primary electrochemical corrosion, using a chloride ion etching solution made of a mixture of 3.5 mol / L hydrochloric acid solution and 0.5 mol / L phosphoric acid solution in a ratio of 1:1, with a solution temperature of 40°C and a corrosion current of 0.5 A / cm 2 The pre-treated aluminum foil was electrochemically corroded under the conditions of 60 Hz and a corrosion time of 10 s.

[0124] S22. Primary chemical etching: using a phosphoric acid solution with a mass percentage concentration of 1% at a solution temperature of 45° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 40 seconds.

[0125] S23, secondary electrochemical corrosion, using a mixture of 1 mol / L hydrochloric acid solution and 0.5 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 30°C and a corrosion current of 0.3 A / cm 2 Under the conditions of a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to electrochemical corrosion again, and the corrosion time was 10 s.

[0126] S24, secondary chemical etching, using a phosphoric acid solution with a mass percentage concentration of 1%, at a solution temperature of 45°C, to chemically etch the aluminum foil after the second electrochemical etching treatment for 40 seconds.

[0127] S25, three-stage electrochemical corrosion, using a 0.5 mol / L chlorine-containing etching solution made from a mixture of potassium chloride solution and titanium trichloride solution, with a solution temperature of 45 ° C and a corrosion current of 0.1 A / cm 2 Under the condition of a frequency of 25 Hz, the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments was subjected to electrochemical corrosion treatment for 10 s.

[0128] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.5% at a solution temperature of 50°C to post-treat the aluminum foil after the holes are formed for 40 seconds;

[0129] Then, the aluminum foil after the primary post-treatment was subjected to a secondary post-treatment for 40 seconds using a phosphorus salt solution with a mass percentage concentration of 1% and a solution temperature of 50°C, which was a mixture of ammonium dihydrogen phosphate solution and trisodium phosphate solution.

[0130] Then, the aluminum foil that had been post-treated twice was post-treated three times for 10 seconds using a 1% by mass ammonium adipate solution at a solution temperature of 40° C., a current of 2 A, and a voltage of 0.2 V.

[0131] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0132] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0133] S51, primary drying, using a drying temperature of 150° C. to dry the cleaned aluminum foil for 3 minutes;

[0134] S52, secondary drying, using a drying temperature of 250° C. to dry the aluminum foil after the primary drying for a second time for 2 minutes;

[0135] S53, three-stage drying, using a drying temperature of 150° C. to dry the aluminum foil after the second drying for 2 minutes to obtain an electrochemical current collector.

[0136] Example 5:

[0137] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0138] S10: Pretreatment: Degreasing the aluminum foil with a thickness of 22 μm using a weak acid degreasing solution prepared by mixing a 2% by mass citric acid solution and a 2% by mass oxalic acid solution in a ratio of 1:1 at a solution temperature of 45°C. Then, anti-passivation treatment was performed on the aluminum foil using a 2% by mass trisodium phosphate solution containing a phosphorus salt at a solution temperature of 50°C.

[0139] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0140] S21, primary electrochemical corrosion, using a chloride ion etching solution composed of a 1:1 mixture of 2 mol / L hydrochloric acid solution and 0.3 mol / L phosphoric acid solution, with a solution temperature of 40°C and a corrosion current of 0.3 A / cm 2 The pre-treated aluminum foil was electrochemically corroded under the conditions of 50 Hz and a corrosion time of 5 s.

[0141] S22. Primary chemical etching: using a 2% by mass phosphoric acid solution at a solution temperature of 45° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 40 seconds.

[0142] S23, secondary electrochemical corrosion, using a mixture of 0.7 mol / L hydrochloric acid solution and 0.3 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 30°C and a corrosion current of 0.3 A / cm 2 Under the conditions of a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to electrochemical corrosion again, and the corrosion time was 10 s.

[0143] S24, secondary chemical etching, using a 2% by mass phosphoric acid solution at a solution temperature of 45°C to chemically etch the aluminum foil after the second electrochemical etching treatment for 40 seconds.

[0144] S25, three-stage electrochemical corrosion, using a 0.5 mol / L chlorine-containing etching solution made from a mixture of hydrochloric acid solution and titanium tetrachloride solution, with a solution temperature of 45°C and a corrosion current of 0.12 A / cm 2 Under the condition of a frequency of 25 Hz, the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments was subjected to electrochemical corrosion treatment for 10 s.

[0145] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.5% at a solution temperature of 50°C to post-treat the aluminum foil after the holes are formed for 45 seconds;

[0146] Then, the aluminum foil after the primary post-treatment was subjected to a secondary post-treatment for 45 seconds using a phosphorus salt solution with a mass percentage concentration of 1.5% and a solution temperature of 50°C;

[0147] Then, the aluminum foil that had been post-treated twice was post-treated three times for 10 seconds using an ammonium adipate solution with a mass percentage concentration of 1.5% at a solution temperature of 45° C., a current of 2 A, and a voltage of 0.2 V.

[0148] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0149] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0150] S51, primary drying, using a drying temperature of 150° C. to dry the cleaned aluminum foil for 3 minutes;

[0151] S52, secondary drying, using a drying temperature of 250° C. to dry the aluminum foil after the primary drying for a second time for 2 minutes;

[0152] S53, three-stage drying, using a drying temperature of 150° C. to dry the aluminum foil after the second drying for 2 minutes to obtain an electrochemical current collector.

[0153] Example 6:

[0154] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0155] S10: Pretreatment: Degreasing the aluminum foil with a thickness of 22 μm using a weak acid degreasing solution prepared by mixing a 1.5% by mass citric acid solution and a 1.5% by mass oxalic acid solution at a ratio of 1:1 at a solution temperature of 45°C. Then, anti-passivation treatment was performed on the aluminum foil using a sodium dihydrogen phosphate solution containing a 1.5% by mass phosphate salt at a solution temperature of 50°C.

[0156] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0157] S21, primary electrochemical corrosion, using a chloride ion etching solution made of a mixture of 4 mol / L hydrochloric acid solution and 0.8 mol / L phosphoric acid solution in a ratio of 1:1, with a solution temperature of 40°C and a corrosion current of 0.5 A / cm 2The pre-treated aluminum foil was electrochemically corroded under the conditions of 55 Hz and a corrosion time of 8 s.

[0158] S22. Primary chemical etching: using a phosphoric acid solution with a mass percentage concentration of 1.5% at a solution temperature of 45° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 40 seconds.

[0159] S23, secondary electrochemical corrosion, using a mixture of 1.5 mol / L hydrochloric acid solution and 0.5 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 30°C and a corrosion current of 0.30 A / cm 2 Under the conditions of a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to electrochemical corrosion again, and the corrosion time was 10 s.

[0160] S24, secondary chemical etching, using a phosphoric acid solution with a mass percentage concentration of 1.5%, at a solution temperature of 45°C, to chemically etch the aluminum foil after the second electrochemical etching treatment for 40 seconds.

[0161] S25, three-stage electrochemical corrosion, using a 0.5 mol / L chlorine-containing etching solution made of a mixture of hydrochloric acid solution, potassium chloride solution and ammonium chloride solution, with a solution temperature of 45 ° C and a corrosion current of 0.1 A / cm 2 Under the condition of a frequency of 25 Hz, the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments was subjected to electrochemical corrosion treatment for 15 s.

[0162] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.8% at a solution temperature of 50°C to post-treat the aluminum foil after the holes are formed for 45 seconds;

[0163] Then, the aluminum foil after the primary post-treatment was subjected to a secondary post-treatment for 45 seconds using a phosphorus salt solution with a mass percentage concentration of 1.5% and a solution temperature of 50°C.

[0164] Then, the aluminum foil that had been post-treated twice was post-treated three times for 10 seconds using an ammoniacal salt solution with a mass percentage concentration of 1.5% prepared by mixing an ammonium adipate solution and an ammonium dihydrogen phosphate solution at a solution temperature of 45°C, a current of 2A, and a voltage of 0.2V.

[0165] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0166] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0167] S51, primary drying, using a drying temperature of 150° C. to dry the cleaned aluminum foil for 3 minutes;

[0168] S52, secondary drying, using a drying temperature of 250° C. to dry the aluminum foil after the primary drying for a second time for 2 minutes;

[0169] S53, three-stage drying, using a drying temperature of 150° C. to dry the aluminum foil after the second drying for 2 minutes to obtain an electrochemical current collector.

[0170] Example 7:

[0171] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0172] S10: Pretreatment: Degreasing the aluminum foil with a thickness of 30 μm using a weak acid degreasing solution prepared by mixing a 0.8% by mass citric acid solution with a 0.8% by mass oxalic acid solution in a ratio of 1:1 at a solution temperature of 45°C. Then, anti-passivation treatment was performed on the aluminum foil using a sodium dihydrogen phosphate solution containing a 0.8% by mass phosphate salt at a solution temperature of 50°C.

[0173] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0174] S21, primary electrochemical corrosion, using a chloride ion etching solution made of a mixture of 5 mol / L hydrochloric acid solution and 0.5 mol / L phosphoric acid solution in a ratio of 1:1, with a solution temperature of 40°C and a corrosion current of 0.5 A / cm 2 The pre-treated aluminum foil was electrochemically corroded under the conditions of 55 Hz and a corrosion time of 10 s.

[0175] S22. Primary chemical etching: using a 0.8% by mass phosphoric acid solution at a solution temperature of 45° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 40 seconds.

[0176] S23, secondary electrochemical corrosion, using a mixture of 0.8 mol / L hydrochloric acid solution and 0.6 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 30°C and a corrosion current of 0.2 A / cm 2Under the conditions of a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to a second electrochemical corrosion treatment, and the corrosion time was 12 s.

[0177] S24, secondary chemical etching, using a 0.8% by mass phosphoric acid solution at a solution temperature of 45° C. to chemically etch the aluminum foil after the second electrochemical etching treatment for 40 seconds.

[0178] S25, three-stage electrochemical corrosion, using a 0.8 mol / L chlorine-containing etching solution made of a mixture of hydrochloric acid solution, potassium chloride solution and titanium trichloride solution, with a solution temperature of 45 ° C and a corrosion current of 0.12 A / cm 2 Under the condition of a frequency of 25 Hz, the aluminum foil, which had been treated alternately with two electrochemical corrosion and chemical corrosion treatments, was subjected to electrochemical corrosion treatment for 17 seconds.

[0179] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.5% at a solution temperature of 50°C to post-treat the aluminum foil after the holes are formed for 45 seconds;

[0180] Then, the aluminum foil after the primary post-treatment was subjected to a secondary post-treatment for 45 seconds using a trisodium phosphate solution containing 1.2% of phosphorus salt by mass and a solution temperature of 55°C.

[0181] Then, the aluminum foil that had been post-treated twice was post-treated three times for 10 seconds using an ammonium adipate solution with a mass percentage concentration of 1.2% at a solution temperature of 45° C., a current of 2 A, and a voltage of 0.2 V.

[0182] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0183] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0184] S51, primary drying, using a drying temperature of 150° C. to dry the cleaned aluminum foil for 3 minutes;

[0185] S52, secondary drying, using a drying temperature of 250° C. to dry the aluminum foil after the primary drying for a second time for 2 minutes;

[0186] S53, three-stage drying, using a drying temperature of 150° C. to dry the aluminum foil after the second drying for 2 minutes to obtain an electrochemical current collector.

[0187] Example 8:

[0188] This embodiment provides a method for preparing an electrochemical current collector, comprising the following steps:

[0189] S10: Pretreatment: Degreasing the aluminum foil with a thickness of 30 μm using a weak acid degreasing solution prepared by mixing a 2.5% by mass citric acid solution and a 2.5% by mass oxalic acid solution in a ratio of 1:1 at a solution temperature of 45°C. Then, anti-passivation treatment is performed on the aluminum foil using a passivation solution prepared by mixing a disodium hydrogen phosphate solution and a trisodium phosphate solution, containing a 2.5% by mass phosphate salt, at a solution temperature of 50°C.

[0190] S20, hole arrangement, using multiple electrochemical etching and chemical etching alternately to etch and pierce the aluminum foil after pretreatment; specifically comprising the following steps:

[0191] S21, primary electrochemical corrosion, using a chloride ion etching solution made of a mixture of 5 mol / L hydrochloric acid solution and 0.8 mol / L phosphoric acid solution in a ratio of 1:1, with a solution temperature of 40°C and a corrosion current of 0.5 A / cm 2 The pre-treated aluminum foil was electrochemically corroded under the conditions of 55 Hz and a corrosion time of 12 s.

[0192] S22. Primary chemical etching: using a phosphoric acid solution with a mass percentage concentration of 2.5% at a solution temperature of 45° C., the aluminum foil after the primary electrochemical etching treatment is chemically etched for 40 seconds.

[0193] S23, secondary electrochemical corrosion, using a mixture of 1.8 mol / L hydrochloric acid solution and 0.8 mol / L zinc sulfate solution in a ratio of 1:1, with a solution temperature of 30 ° C and a corrosion current of 0.3 A / cm 2 Under the conditions of a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion was subjected to electrochemical corrosion again, and the corrosion time was 15 s.

[0194] S24, secondary chemical etching, using a phosphoric acid solution with a mass percentage concentration of 2.5%, at a solution temperature of 45°C, to chemically etch the aluminum foil after the second electrochemical etching treatment for 40 seconds.

[0195] S25, three-stage electrochemical corrosion, using a 0.8 mol / L chlorine-containing etching solution made from a mixture of hydrochloric acid solution and ammonium chloride solution, with a solution temperature of 45 ° C and a corrosion current of 0.15 A / cm 2 Under the condition of a frequency of 25 Hz, the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments was subjected to electrochemical corrosion treatment for 20 seconds.

[0196] S30, post-treatment, using a zinc sulfate solution with a mass percentage concentration of 0.8% at a solution temperature of 50°C to post-treat the aluminum foil after the holes are formed for 45 seconds;

[0197] Then, the aluminum foil was subjected to a secondary post-treatment for 45 seconds using a phosphorus salt solution prepared by mixing ammonium dihydrogen phosphate solution and trisodium phosphate solution with a mass percentage concentration of 2.5% and a solution temperature of 55°C.

[0198] Then, the aluminum foil that had been post-treated twice was post-treated three times for 10 seconds using an ammoniacal salt solution with a mass percentage concentration of 2.5% prepared by mixing an ammonium adipate solution and an ammonium dihydrogen phosphate solution at a solution temperature of 45°C, a current of 2A, and a voltage of 0.2V.

[0199] S40, cleaning, using 3-6 water tanks to clean the aluminum foil after post-processing, and then using a scraper to scrape off the water on part of the aluminum foil.

[0200] S50, drying, performing multi-stage drying on the cleaned aluminum foil, specifically comprising the following steps:

[0201] S51, primary drying, using a drying temperature of 150° C. to dry the cleaned aluminum foil for 3 minutes;

[0202] S52, secondary drying, using a drying temperature of 250° C. to dry the aluminum foil after the primary drying for a second time for 2 minutes;

[0203] S53, three-stage drying, using a drying temperature of 150° C. to dry the aluminum foil after the second drying for 2 minutes to obtain an electrochemical current collector.

[0204] The holes on the surface of the aluminum foil after the holes in Example 4 were observed under SEM, for example:

[0205] The aluminum foil after primary electrochemical corrosion was observed under SEM. The results are as follows Figure 1 shown; from Figure 1 It can be seen that the surface of the aluminum foil has dispersed pore structures of varying sizes, with pore diameters ranging from 1μm to 3μm and pores ranging from 2μm to 15μm.

[0206] The aluminum foil after secondary electrochemical corrosion was observed under SEM. The results are as follows Figure 2 shown; from Figure 2 It can be seen that compared with Figure 1 In general, not only the original holes on the surface of the aluminum foil are deepened and enlarged, but also many smaller and more fragmented holes are formed between the large holes.

[0207] The aluminum foil after the third stage of electrochemical corrosion was observed under SEM. The results are as follows: Figure 3 shown; from Figure 3 It can be seen that compared with Figure 2 For the aluminum foil, there is no obvious change in the holes on the surface, and only the inside of the aluminum foil is slightly enlarged. The aluminum foil after only the third level of electrochemical corrosion is observed under SEM, and the results are as follows Figure 4 As shown, from Figure 4 It can be seen that many tiny holes are formed on the surface of the aluminum foil.

[0208] It can be seen that the electrochemical current collector prepared by the above-mentioned electrochemical current collector preparation method adopts the method of alternating multiple electrochemical corrosion and chemical corrosion to etch holes in the aluminum foil, which can make the holes on the surface of the aluminum foil smaller and more fragmented, and the hole layer has more rivet structures, so that the slurry formulas of different processes can be effectively filled into the etched holes to form a stable electrode structure, ensuring the efficient transmission of electrons and ions, thereby effectively extending the service life of the electrochemical current collector.

[0209] Performance Testing

[0210] Etching depth test: The electrochemical current collector etched foils prepared in Examples 1-8 were cut into 10 mm × 10 mm foils. The electrochemical current collectors of commercially available supercapacitors 1-4 were dissected and taken. Each was made into a metallographic grinding table. After a pre-treatment process including grinding, polishing, soaking, and gold spraying, the etching depth was measured using an electron microscope.

[0211] Peel strength test: The electrochemically etched foil prepared in Examples 1-8 was formed into an electrode. The electrode was folded and a portion of the electrode was peeled off from the middle end of the electrode to leave a bond length of (50±1) mm between the electrode and the double-sided tape. The untaped end of the steel plate was vertically clamped in the fixture of a tensile testing machine, with the free end of the electrode pointing vertically downward. After the equipment was reset, the electrode was clamped in another fixture and peeled continuously at a rate of (300±10) mm / s.

[0212] Internal resistance test: The electrochemically etched foils prepared in Examples 1-8 were made into electrodes. 8 mm × 20 mm electrodes were used to make 2.7 V 3.3 F supercapacitors. The internal resistance of the electrodes was measured against commercial supercapacitors 1-4 according to 6.4.1.4 of GB / T34870.1.

[0213] 1000h life test: The electrochemically etched foils prepared in Examples 1-8 were made into electrodes. 8mm×20mm pieces were made into 2.7V3.3F supercapacitors. These and commercially available supercapacitors 1-4 were placed in a high-temperature test chamber set at 85±2°C for 1000h. The electrodes were then placed at room temperature for 24h. The internal resistance was measured according to 6.4.1.4 of GB / T34870.1.

[0214] Using the above test method, 2.7V3.3F supercapacitors made using the electrochemical current collectors of Examples 1-8 and commercially available 2.7V3.3F supercapacitors were tested respectively. The measured etching depth, peel strength, internal resistance, and 1000h high temperature life results are shown in Table 1.

[0215] Table 1 Performance parameters of each test case

[0216]

[0217] As can be seen from Table 1, the electrochemical current collectors prepared by processing aluminum foil with a thickness of 18μm-30μm in Examples 1-8 effectively deepen the etching depth of the current collector surface compared to the current collectors in existing commercial supercapacitors. They can be used in supercapacitors, effectively increase the peel strength and service life of the supercapacitor, and reduce the internal resistance of the supercapacitor.

[0218] The above description is merely an example and illustration of the structure of the present invention. Although the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and such obvious alternatives are all within the scope of protection of the present invention.

Claims

1. A method for preparing an electrochemical current collector, characterized in that: The following steps are involved: Pretreatment: using weak acid degreasing solution and anti-over-degreasing passivation solution to pretreat the aluminum foil; Hole arrangement: multiple electrochemical etching and chemical etching are performed alternately to etch and pierce the aluminum foil after pretreatment; Post-treatment: After the aluminum foil is corroded and pierced with holes, it is post-treated with zinc sulfate solution and phosphorus salt solution, and then the aluminum foil is subjected to electrical post-treatment with ammonia salt solution to form an oxide protective film; wherein, The hole arrangement step includes the following steps: Primary electrochemical corrosion: using chloride ion etching solution to electrochemically corrode the pre-treated aluminum foil; Primary chemical etching, using phosphoric acid solution to chemically etch the aluminum foil after the primary electrochemical etching treatment; Secondary electrochemical corrosion: using a mixture of hydrochloric acid solution and zinc sulfate solution, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion is subjected to electrochemical corrosion again; Secondary chemical etching: using phosphoric acid solution to chemically etch the aluminum foil after the electrochemical etching treatment; The third-level electrochemical etching uses a chlorine-containing etching solution to electrochemically etch the aluminum foil after two alternating electrochemical and chemical etching treatments.

2. The method for preparing an electrochemical current collector according to claim 1, wherein: In the primary electrochemical corrosion step, the chloride ion etching solution is a mixture of 1 mol / L-6 mol / L hydrochloric acid solution and 0.1 mol / L-1 mol / L phosphoric acid solution in a ratio of 1:1, the solution temperature is 35°C-45°C; the corrosion current is 0.1 A / cm 2 -1A / cm 2 , frequency is 45 Hz-70 Hz; corrosion time is 5s-12s.

3. The method for preparing an electrochemical current collector according to claim 1, wherein: In the primary chemical etching and the secondary chemical etching steps, the phosphoric acid solution is a phosphoric acid solution with a mass percentage concentration of 0.1%-3%, a solution temperature of 35° C.-55° C., and an etching time of 20s-60s.

4. The method for preparing an electrochemical current collector according to claim 1, wherein: In the secondary electrochemical corrosion step, the mixed solution is prepared by mixing 0.1mol / L-2mol / L hydrochloric acid solution and 0.1mol / L-1mol / L zinc sulfate solution in a ratio of 1:1, the solution temperature is 25℃-35℃; the corrosion current is 0.1 A / cm 2 -0.5A / cm 2 , frequency is 25 Hz-45 Hz; corrosion time is 5s-15s.

5. The method for preparing an electrochemical current collector according to claim 1, wherein: In the three-stage electrochemical etching step, the chlorine-containing etching solution is a 0.1 mol / L-1 mol / L chlorine-containing etching solution, which is a mixture of one or more of hydrochloric acid solution, potassium chloride solution, titanium tetrachloride solution, titanium trichloride solution or ammonium chloride solution; the solution temperature is 35°C-55°C; the corrosion current is 0.05 A / cm 2 -0.2A / cm 2 , frequency is 15 Hz -35 Hz, and corrosion time is 5s-20s.

6. The method for preparing an electrochemical current collector according to claim 1, wherein: In the post-treatment step, the zinc sulfate solution is a zinc sulfate solution with a mass percentage concentration of 0.1%-1%, the solution temperature is 35° C.-65° C., and the post-treatment time is 20s-65s.

7. The method for preparing an electrochemical current collector according to claim 1, wherein: In the post-treatment step, the phosphorus-containing salt solution is a phosphorus-containing salt solution with a mass percentage concentration of 0.1%-3%, which is a mixture of one or two of ammonium dihydrogen phosphate solution, diammonium hydrogen phosphate solution, and trisodium phosphate solution. The temperature of the solution is 35°C-70°C; and the post-treatment time is 20s-65s.

8. The method for preparing an electrochemical current collector according to claim 1, wherein: In the post-treatment step, the ammonia-containing salt solution is an ammonia-containing salt solution with a mass percentage concentration of 0.1%-3%, which is a mixture of one or more of ammonium adipate solution, diammonium hydrogen phosphate solution, and ammonium dihydrogen phosphate solution. The temperature of the solution is 30°C-55°C; the post-treatment current is 2A, the voltage is 0.2V, and the post-treatment time is 5s-15s.

9. The method for preparing an electrochemical current collector according to claim 1, wherein: In the pretreatment step, the weak acid degreasing solution is prepared by mixing a citric acid solution with a mass percentage concentration of 0.1%-3% and an oxalic acid solution with a mass percentage concentration of 0.1%-3% in a ratio of 1:1, and the solution temperature is 35°C-55°C.

10. The method for preparing an electrochemical current collector according to claim 1, wherein: In the pretreatment step, the anti-over-oiling passivation solution is a mixture of one or more of ammonium dihydrogen phosphate solution, sodium dihydrogen phosphate solution, disodium hydrogen phosphate solution, and trisodium phosphate solution, the mass percentage concentration of the phosphorus salt is 0.1%-3%, and the solution temperature is 50°C-70°C.

11. The method for preparing an electrochemical current collector according to claim 1, wherein: The following steps are also included: Cleaning: Use a multi-stage water tank to clean the aluminum foil after post-processing; Drying: The cleaned aluminum foil is dried in multiple stages at a temperature of 80°C-350°C; Wherein, the drying step includes the following steps: First-stage drying: drying the cleaned aluminum foil at a temperature of 80°C-200°C for 1-3 minutes; Secondary drying: use a drying temperature of 200-350°C to dry the aluminum foil again after the primary drying, and the drying time is 2-3 minutes; The third stage drying uses a drying temperature of 80℃-200℃ to dry the aluminum foil again after the second drying, and the drying time is 2min-3min.

12. An electrochemical current collector, characterized in that: The electrochemical current collector is prepared by processing an aluminum foil with a thickness of 18 μm to 30 μm using the electrochemical current collector preparation method according to any one of claims 1 to 11.

13. Use of an electrochemical current collector prepared by processing an aluminum foil with a thickness of 18 μm to 30 μm using the method for preparing an electrochemical current collector according to any one of claims 1 to 11 in a supercapacitor.

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