Electrochemical current collector and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrochemistry, and particularly relates to an electrochemical current collector and a preparation method and application thereof.The preparation method comprises the following steps that pretreatment is conducted, specifically, aluminum foil is pretreated through a weak acid oil removal solution and an excessive oil removal prevention passivation solution; hole distribution: performing corrosion and hole distribution on the pretreated aluminum foil by alternately performing electrochemical corrosion and chemical corrosion for multiple times; and post-treatment: carrying out primary post-treatment on the aluminum foil subjected to corrosion and hole arrangement by utilizing a zinc sulfate solution and a phosphorus-containing salt solution, and then carrying out power-up post-treatment on the aluminum foil subjected to the primary post-treatment by utilizing an ammonia-containing salt solution to form an oxidation protection film. According to the preparation method of the electrochemical current collector provided by the invention, the prepared electrochemical current collector can enable slurry formulas of different processes to be effectively filled into etching holes, so that a stable electrode structure is formed, efficient transmission of electrons and ions is ensured, and the service life of a supercapacitor is further effectively prolonged.

Description

Technical Field

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

[0002] The current collector is a key component for conducting current in a supercapacitor. If the adhesion between the current collector and the active material is poor, the active material is likely to fall off, which will increase the internal resistance of the supercapacitor, cause uneven current conduction, and ultimately lead to unstable performance of the supercapacitor. Moreover, with the increase in the number of charge and discharge cycles, the shedding of the active material on the current collector with poor adhesion will be more serious, which will reduce the effective reaction area of the supercapacitor, lead to an accelerated decay of the supercapacitor capacity, and thus shorten the service life of the supercapacitor. Therefore, the surface properties of the current collector have a great influence on the production and performance of the supercapacitor.

[0003] The good combination of the pores of the current collector and the slurry is one of the key factors for improving the performance of the supercapacitor. A reasonable pore structure of the current collector can promote the uniform deposition of the active material in the slurry, enhance the electrochemical reaction area, and thus improve the capacity and cycle stability of the supercapacitor. In the prior art, due to the defects in the preparation technology of the current collector, it is easy to cause asymmetry in the two-sided structure and asymmetry in the contact resistance of the two-sided coatings, resulting in the uneven release of the capacities of the two-sided electrodes; at the same time, the two-sided asymmetry will also cause inconsistent coating adhesion strengths, resulting in a serious imbalance in the charge and discharge cycle lives of the two sides, and further accelerating the decay of the supercapacitor capacity. In addition, aluminum foils are basically rolled from thick aluminum ingots. During the rolling process, it is necessary to control the contact between the aluminum ingot and the rolling roll, so generally a lubricant is added to the surface of the aluminum foil to protect the aluminum ingot and the rolling roll. Therefore, the surface lubricant will also have a certain impact on the supercapacitor, and it is necessary to remove the lubricant from the surface of the aluminum foil.

[0004] In summary, studying a technology that can effectively improve the adhesion to the active material, reduce the internal resistance of the supercapacitor, improve the energy transfer efficiency and the performance stability of the supercapacitor 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] To solve the above problems, the invention object 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-overdegreasing passivation solution are used to degrease the aluminum foil, improving the uniformity of the surface energy of each part of the aluminum foil. Then, through multi-level electrochemical etching of holes, the slurry formulations 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. Additionally, the subsequent process forms a film protection layer on the surface of the electrochemical current collector, enabling the electrochemical current collector to remain stable in various harsh environments. This delicate interface regulation can provide a solid foundation for the development of high-performance supercapacitors.

[0006] The invention object of the second aspect of the present application is to provide an electrochemical current collector prepared by using the above method for preparing an electrochemical current collector, which can effectively improve the adhesion with the active material, reduce the internal resistance of the supercapacitor, improve the energy transmission efficiency and the performance stability of the supercapacitor, and thus effectively extend the service life of the supercapacitor.

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

[0008] To achieve the above object, the present invention provides the following technical solutions: The method for preparing an electrochemical current collector in the present invention includes the following steps: Pretreatment: Using a weak acid degreasing solution and an anti-overdegreasing passivation solution to pretreat the aluminum foil; Hole layout: Using multiple alternations of electrochemical corrosion and chemical corrosion to corrode and layout holes on the pretreated aluminum foil; Post-treatment: After using a zinc sulfate solution and a phosphorus salt solution to conduct primary post-treatment on the aluminum foil after corrosion and hole layout, then using an ammonium salt solution to conduct power-on post-treatment on the aluminum foil after primary post-treatment to form an oxidation protection film; wherein, In the hole layout step, it includes the following steps: Primary electrochemical corrosion: Using a chloride ion etching solution to conduct electrochemical corrosion treatment on the aluminum foil after pretreatment; Primary chemical corrosion: Using a phosphoric acid solution to conduct chemical corrosion treatment on the aluminum foil after primary electrochemical corrosion treatment; Secondary electrochemical corrosion: Using a mixed solution of a hydrochloric acid solution and a zinc sulfate solution to conduct secondary electrochemical corrosion treatment on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion; Secondary chemical corrosion: Using a phosphoric acid solution to conduct secondary chemical corrosion treatment on the aluminum foil after secondary electrochemical corrosion treatment.

[0009] Tertiary electrochemical corrosion: Electrochemical corrosion treatment is carried out on the aluminum foil that has been alternately treated by two times of electrochemical corrosion and chemical corrosion using a chlorine-containing etching solution.

[0010] Further, in the primary electrochemical corrosion step, the chloride ion etching solution is composed of a hydrochloric acid solution with a concentration of 1 mol / L - 6 mol / L and a phosphoric acid solution with a concentration of 0.1 mol / L - 1 mol / L mixed in a ratio of 1:1, and the solution temperature is 35°C - 45°C; the corrosion current is 0.1 A / cm 2 -1 A / cm 2 , the frequency is 45 Hz - 70 Hz; the corrosion time is 5 s - 12 s.

[0011] Further, in the primary chemical corrosion and the secondary chemical corrosion steps, the phosphoric acid solution is a phosphoric acid solution with a mass percentage concentration of 0.1% - 3%, the solution temperature is 35°C - 55°C, and the corrosion time is 20 s - 60 s.

[0012] Further, in the secondary electrochemical corrosion step, the mixed solution is composed of a hydrochloric acid solution with a concentration of 0.1 mol / L - 2 mol / L and a zinc sulfate solution with a concentration of 0.1 mol / L - 1 mol / L mixed in a ratio of 1:1, and the solution temperature is 25°C - 35°C; the corrosion current is 0.1 A / cm 2 -0.5 A / cm 2 , the frequency is 25 Hz - 45 Hz; the corrosion time is 5 s - 15 s.

[0013] Further, in the tertiary electrochemical corrosion step, the chlorine-containing etching solution is a chlorine-containing etching solution with a concentration of 0.1 mol / L - 1 mol / L, which is composed of one or several 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 -0.2 A / cm 2 , the frequency is 15 Hz - 35 Hz, and the corrosion time is 5 s - 20 s.

[0014] Further, 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 20 s - 65 s.

[0015] Further, 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 composed of one or two of ammonium dihydrogen phosphate solution, diammonium hydrogen phosphate solution, sodium phosphate solution, and the solution temperature is 35°C - 70°C; the post-treatment time is 20 s - 65 s.

[0016] Further, in the post-treatment step, the ammonium salt-containing solution is an ammonium salt-containing solution with a mass percentage concentration of 0.1% - 3%, which is composed of one or more of ammonium adipate solution, diammonium hydrogen phosphate solution, and ammonium dihydrogen phosphate solution, and the temperature of the solution is 30°C - 55°C; the current for post-treatment is 2A, the voltage is 0.2V, and the post-treatment time is 5s - 15s.

[0017] Further, in the pre-treatment step, the weak acid degreasing solution is composed of 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% mixed in a ratio of 1:1, and the solution temperature is 35°C - 55°C.

[0018] Further, in the pre-treatment step, the anti-over-degreasing passivation solution is composed of one or several of diammonium hydrogen 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.

[0019] Further, the method for preparing the electrochemical current collector further includes the following steps: Cleaning, using a multi-stage water tank to clean the aluminum foil after post-treatment; Drying, performing multi-stage drying on the cleaned aluminum foil, and the drying temperature is 80°C - 350°C; Among them, in the drying step, the following steps are included: Primary drying, using a drying temperature of 80°C - 200°C to dry the cleaned aluminum foil, and the drying time is 1min - 3min; Secondary drying, using a drying temperature of 200°C - 350°C to re-dry the aluminum foil after primary drying, and the drying time is 2min - 3min; Tertiary drying, using a drying temperature of 80°C - 200°C to re-dry the aluminum foil after secondary drying, and the drying time is 2min - 3min.

[0020] The electrochemical current collector in the present invention is prepared by processing an aluminum foil using the above method for preparing an electrochemical current collector, and the thickness of the aluminum foil is 18μm - 30μm.

[0021] Application of the electrochemical current collector prepared by processing an aluminum foil with a thickness of 18μm - 30μm using the method for preparing an electrochemical current collector in the present invention in a supercapacitor.

[0022] Based on the above technical solutions, the present invention has the following technical effects: 1. The method for preparing an electrochemical current collector provided by the present invention first uses a weak acid degreasing solution and an anti-over-degreasing passivation solution to degrease the aluminum foil, improving the uniformity of the surface energy of each part of the aluminum foil. Subsequently, the aluminum foil is corroded and perforated by alternately performing multiple electrochemical corrosions and chemical corrosions, so that the holes on the surface of the aluminum foil are smaller and more fragmented, and there are more rivet structures in the hole layer. As a result, the slurry formulations 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. Then, the perforated aluminum foil is post-treated first with a zinc sulfate solution and a phosphorus-containing salt solution, and then the preliminarily post-treated aluminum foil is post-treated with an ammonia salt solution under electrification, so as to form a film protection layer on the surface of the electrochemical current collector, which can remain stable in various harsh environments. This delicate interface regulation can provide a solid foundation for the development of high-performance supercapacitors.

[0023] 2. The electrochemical current collector provided by the present invention has a hole structure on its surface, which can enable the slurry to flow into it quickly and is extremely difficult to peel off, improving the adhesion with the active material, reducing the internal resistance of the supercapacitor, thereby improving the energy transmission efficiency and the performance stability of the supercapacitor, and further effectively extending the service life of the supercapacitor. Moreover, the electrochemical current collector has excellent corrosion resistance and can remain stable in various harsh environments, optimizing the interfacial reaction kinetics of the supercapacitor, thereby further improving the performance of the supercapacitor and extending the service life of the supercapacitor.

[0024] 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. Description of the Drawings

[0025] Figure 1 SEM image of the surface of the aluminum foil after primary electrochemical corrosion in Example 4.

[0026] Figure 2 SEM image of the surface of the aluminum foil after secondary electrochemical corrosion in Example 4.

[0027] Figure 3 SEM image of the surface of the aluminum foil after tertiary electrochemical corrosion in Example 4.

[0028] Figure 4 SEM image of the surface of the aluminum foil after only tertiary electrochemical corrosion in Example 4. Detailed Description of the Invention

[0029] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. Preferred embodiments of the present invention are given. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0030] Before further describing various embodiments of the compounds / compositions and methods of the present disclosure in more detail by way of 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 construed in a limiting sense. The inventive concept of the present disclosure can have 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 and 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 employed herein are for descriptive purposes and should not be considered limiting unless otherwise indicated. Additionally, in the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present disclosure.

[0031] However, it will be apparent to those of ordinary skill in the art that the embodiments of the present disclosure can be practiced without these specific details. In other instances, features well known to those of ordinary skill in the art have not been described in detail to avoid unnecessary complication of the description. It is intended that all alternatives, substitutions, modifications, and equivalents that are apparent to those of ordinary skill in the art be included within the scope of the present disclosure. According to the present disclosure, all of the compounds / compositions disclosed herein and their preparation methods, applications, and uses can be prepared and implemented without undue experimentation.

[0032] Therefore, although the compounds / compositions and methods of the present disclosure have been described in accordance with specific embodiments, it will be apparent to those skilled in the art that changes can be made to the formulations, compounds or compositions, and / or methods and to the steps or the order of steps of the methods described herein without departing from the spirit and scope of the inventive concept of the present disclosure.

[0033] As used herein, any reference to "an embodiment" or "embodiments" means that a particular element, feature, structure, or property described in connection with that embodiment is included in at least one embodiment. The phrase "in one embodiment" that appears in the specification in multiple places does not necessarily refer to the same embodiment.

[0034] Unless otherwise defined herein, scientific and technical terms used in connection with this disclosure shall have the meanings commonly understood by one of ordinary skill in the art. In addition, unless the context requires otherwise, singular terms shall include the plural and plural terms shall include the singular.

[0035] In a first aspect, a method for preparing an electrochemical current collector in the present invention includes the following steps: S10. Pretreatment: The aluminum foil is pretreated with a weak acid degreasing solution and an anti-over-degreasing passivation solution. Further, a multi-tank method is used for pretreating the aluminum foil. Since the oil stains on the aluminum foils produced by different manufacturers are different and the oil stains on various parts of the aluminum foil are not uniform, after degreasing with the weak acid degreasing solution, the anti-over-degreasing passivation solution is used for passivation treatment to prevent over-corrosion of the aluminum foil after local degreasing, thereby preventing non-uniform surface energy of various parts of the aluminum foil and causing non-uniform pore distribution after primary electrification.

[0036] The oil stains floating out of the pretreatment tank overflow from the four sides of the upper part of the pretreatment tank. For the oil stains brought by the aluminum foil through the pretreatment tank into the primary electrolytic tank, in addition to overflowing from the upper part of the electrolytic tank, activated carbon strips can be added to adsorb the oil stains. Preferably, in the pretreatment step, the weak acid degreasing solution is composed of 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% mixed in a ratio of 1:1, and the solution temperature is 35°C - 55°C. The anti-over-degreasing passivation solution is composed of one or several of ammonium dihydrogen phosphate solution, sodium dihydrogen phosphate solution, disodium hydrogen phosphate solution, and trisodium phosphate solution, and the mass percentage concentration of the phosphorus salt is 0.1%-3%, and the solution temperature is 50°C - 70°C.

[0037] S20. Pore formation: The pretreated aluminum foil is subjected to corrosion pore formation by alternately performing multiple electrochemical corrosions and chemical corrosions. Further, it specifically includes the following steps: S21. Primary electrochemical corrosion: The pretreated aluminum foil is subjected to electrochemical corrosion treatment with a chloride ion etching solution. Preferably, the chloride ion etching solution is composed of a hydrochloric acid solution with a concentration of 1 mol / L - 6 mol / L and a phosphoric acid solution with a concentration of 0.1 mol / L - 1 mol / L mixed in a ratio of 1:1, and the solution temperature is 35°C - 45°C; the corrosion current is 0.1 A / cm 2 -1A / cm 2 , the frequency is 45Hz - 70Hz; the corrosion time is 5s - 12s. This step uses a combination of high current, high frequency, and high chloride ions to open the holes on the aluminum foil surface as much as possible.

[0038] S22. Primary chemical corrosion: The aluminum foil after primary electrochemical corrosion is chemically corroded using a phosphoric acid solution. Preferably, the phosphoric acid solution is a phosphoric acid solution with a mass percentage concentration of 0.1% - 3%, the solution temperature is 35°C - 55°C, and the corrosion time is 20 s - 60 s. In this step, using the phosphoric acid solution can dissolve some of the miscellaneous small holes on the non-main channels of the primary electrochemical corrosion, paving the way for the pore formation in the subsequent secondary electrochemical corrosion.

[0039] S23. Secondary electrochemical corrosion: The aluminum foil after primary electrochemical corrosion and primary chemical corrosion is electrochemically corroded again using a mixed solution of hydrochloric acid solution and zinc sulfate solution. Preferably, the mixed solution is composed of a hydrochloric acid solution with a concentration of 0.1 mol / L - 2 mol / L and a zinc sulfate solution with a concentration of 0.1 mol / L - 1 mol / L mixed in a ratio of 1:1, and the solution temperature is 25°C - 35°C; the corrosion current is 0.1 A / cm 2 - 0.5 A / cm 2 , the frequency is 25 Hz - 45 Hz; the corrosion time is 5 s - 15 s. In this step, the combination of medium current, medium frequency, and medium chloride ions can make the pore formation drill deeper holes on the basis of the original holes, so that the holes are smaller and more fragmented.

[0040] S24. Secondary chemical corrosion: The aluminum foil after secondary electrochemical corrosion is chemically corroded again using a phosphoric acid solution. Preferably, the phosphoric acid solution is a phosphoric acid solution with a mass percentage concentration of 0.1% - 3%, the solution temperature is 35°C - 55°C, and the corrosion time is 20 s - 60 s. The purpose is the same as that of step S22, which can dissolve some of the miscellaneous small holes on the non-main channels of the secondary electrochemical corrosion, paving the way for the pore formation in the subsequent tertiary electrochemical corrosion.

[0041] S25. Tertiary electrochemical corrosion: The aluminum foil after being alternately treated by two electrochemical corrosions and chemical corrosions is electrochemically corroded using a chlorine-containing etching solution. Among them, the chlorine-containing etching solution is a chlorine-containing etching solution with a concentration of 0.1 mol / L - 1 mol / L, which is composed of one or several of hydrochloric acid solution, potassium chloride solution, titanium tetrachloride solution, titanium trichloride solution, or ammonium chloride solution; preferably, the chlorine-containing etching solution is composed of one or several of titanium tetrachloride solution and titanium trichloride solution. The solution temperature is 35°C - 55°C; the corrosion current is 0.05 A / cm 2 - 0.2 A / cm 2, with a frequency of 15 Hz - 35 Hz and an etching time of 5 s - 20 s. In this step, a titanium-containing weak acid salt is used as the etching solution. One reason is that titanium can form a Ti-Al alloy with higher conductivity with the aluminum foil, and the other is that the weak Cl ions can better drill disordered holes into the pores, so that there are more rivet structures in the inner layer of the pores, thereby improving the adhesion between the electrochemical current collector and the active material, improving the energy transmission efficiency and the performance stability of the supercapacitor, and effectively extending the service life of the supercapacitor.

[0042] S30. Post-treatment: After initially post-treating the aluminum foil with etched holes using a zinc sulfate solution and a phosphorus-containing salt solution, then perform an electro-assisted post-treatment on the aluminum foil after the initial post-treatment using an ammonium 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 20 s - 65 s. The phosphorus-containing salt solution is a phosphorus-containing salt solution with a mass percentage concentration of 0.1% - 3%, which is composed of one or two of ammonium dihydrogen phosphate solution, diammonium hydrogen phosphate solution, and trisodium phosphate solution, and the solution temperature is 35°C - 70°C; the post-treatment time is 20 s - 65 s. The ammonium salt solution is an ammonium salt solution with a mass percentage concentration of 0.1% - 3%, which is composed 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 current for the post-treatment is 2 A, the voltage is 0.2 V, and the post-treatment time is 5 s - 15 s. In this step, first post-treat the aluminum foil with etched holes using a zinc sulfate solution and a phosphorus-containing salt solution, and then perform an electro-assisted post-treatment on the aluminum foil after the preliminary post-treatment using an ammonium salt solution, so as to form a film protective layer on the surface of the electrochemical current collector and maintain stability in various harsh environments. This fine interface regulation can provide a solid foundation for the development of high-performance supercapacitors.

[0043] S40. Cleaning: Use a multi-stage water tank to clean the aluminum foil after the post-treatment is completed; preferably, the multi-stage water tank has 3 - 6 water tanks, and there are two groups of wiper rods on the outlet water tank to wipe dry the water on part of the aluminum foil.

[0044] S50. Drying: Perform multi-stage drying on the cleaned aluminum foil, and the drying temperature is 80°C - 350°C; specifically, it includes the following steps: S51. Primary drying: Use a drying temperature of 80°C - 200°C to dry the cleaned aluminum foil, and the drying time is 1 min - 3 min; S52. Secondary drying: Use a drying temperature of 200°C - 350°C to re-dry the aluminum foil after the first drying, and the drying time is 2 min - 3 min; S53. Tertiary drying: The aluminum foil after secondary drying is dried again at a drying temperature of 80°C - 200°C for 2 min - 3 min.

[0045] The drying step adopts a form of changing from low to high temperature and then from high to low temperature, which can effectively ensure the uniformity and quality of the surface drying of the electrochemical current collector, and thus ensure the quality of the preparation of the electrochemical current collector.

[0046] Aluminum foil with a thickness of 18μm - 30μm can be used to prepare an electrochemical current collector by the above electrochemical current collector preparation method and applied to supercapacitors.

[0047] Example 1: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: Use a weak acid degreasing solution prepared by mixing a citric acid solution with a mass percentage concentration of 1.5% and an oxalic acid solution with a mass percentage concentration of 1.5% in a ratio of 1:1 to degrease the aluminum foil with a thickness of 18μm at a solution temperature of 45°C. Then, use an ammonium dihydrogen phosphate solution with a mass percentage concentration of phosphorus salt of 2% to passivate the aluminum foil at a solution temperature of 50°C.

[0048] S20. Hole distribution: Alternately perform multiple electrochemical corrosion and chemical corrosion on the pretreated aluminum foil for corrosion hole distribution; specifically including the following steps: S21. Primary electrochemical corrosion: Use a chloride ion etching solution prepared by mixing a 2mol / L hydrochloric acid solution and a 0.8mol / L phosphoric acid solution in a ratio of 1:1 to perform electrochemical corrosion treatment on the pretreated aluminum foil at a solution temperature of 40°C, a corrosion current of 0.8A / cm 2 and a frequency of 55Hz for 5s.

[0049] S22. Primary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 1.5% to perform chemical corrosion treatment on the aluminum foil after primary electrochemical corrosion treatment at a solution temperature of 45°C for 40s.

[0050] S23. Secondary electrochemical corrosion: Use a mixed solution prepared by mixing a 1.5mol / L hydrochloric acid solution and a 0.7mol / L zinc sulfate solution in a ratio of 1:1 to perform secondary electrochemical corrosion treatment on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion at a solution temperature of 30°C, a corrosion current of 0.3A / cm 2 and a frequency of 35Hz for 5s.

[0051] S24. Secondary 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 second electrochemical etching treatment is subjected to a second chemical etching treatment for 40 s.

[0052] S25. Tertiary electrochemical etching: Using a 0.5 mol / L chlorine-containing etching solution composed of a potassium chloride solution and a titanium tetrachloride solution, at a solution temperature of 45°C and an etching current of 0.1 A / cm 2 and a frequency of 25 Hz, the aluminum foil after the alternating treatment of two electrochemical etching and chemical etching is subjected to an electrochemical etching treatment for 5 s.

[0053] S30. Post-treatment: Using a zinc sulfate solution with a mass percentage concentration of 0.5%, at a solution temperature of 50°C, the aluminum foil after perforation is subjected to a first post-treatment for 55 s; Then, using a phosphorus-containing salt solution with a mass percentage concentration of 1.5% composed of an ammonium dihydrogen phosphate solution and a trisodium phosphate solution, at a solution temperature of 50°C, the aluminum foil after the first post-treatment is subjected to a second post-treatment for 45 s; Then, using an ammonia-containing salt solution with a mass percentage concentration of 1.5% composed of an ammonium adipate solution and a diammonium hydrogen phosphate solution, at a solution temperature of 45°C, a current of 2 A, and a voltage of 0.2 V, the aluminum foil after the second post-treatment is subjected to a third post-treatment for 10 s.

[0054] S40. Cleaning: After the aluminum foil after post-treatment is cleaned using 3 - 6 water tanks, a water scraping rod is used to scrape off the water on part of the aluminum foil.

[0055] S50. Drying: The cleaned aluminum foil is subjected to multi-stage drying, specifically including the following steps: S51. Primary drying: Using a drying temperature of 150°C, the cleaned aluminum foil is dried for 3 min; S52. Secondary drying: Using a drying temperature of 250°C, the aluminum foil after the first drying is dried again for 2 min; S53. Tertiary drying: Using a drying temperature of 150°C, the aluminum foil after the second drying is dried again for 2 min to obtain the electrochemical current collector.

[0056] Example 2: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: Use a weak acid degreasing solution prepared by mixing a citric acid solution with a mass percentage concentration of 3% and an oxalic acid solution with a mass percentage concentration of 3% in a ratio of 1:1 to degrease an aluminum foil with a thickness of 18 μm at a solution temperature of 35°C. Then, use a passivation solution to prevent over-degreasing, which is a mixture of a sodium dihydrogen phosphate solution and a trisodium phosphate solution with a mass percentage concentration of phosphorus salt of 3%, to perform passivation treatment on the aluminum foil at a solution temperature of 70°C.

[0057] S20. Hole drilling: Use the method of alternating multiple electrochemical corrosion and chemical corrosion to corrode and drill holes in the pretreated aluminum foil; specifically, it includes the following steps: S21. Primary electrochemical corrosion: Use a chloride ion etching solution prepared by mixing a 6 mol / L hydrochloric acid solution and a 1 mol / L phosphoric acid solution in a ratio of 1:1 to perform electrochemical corrosion treatment on the pretreated aluminum foil at a solution temperature of 35°C, a corrosion current of 1 A / cm 2 and a frequency of 70 Hz for 5 s.

[0058] S22. Primary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 3% to perform chemical corrosion treatment on the aluminum foil after primary electrochemical corrosion treatment at a solution temperature of 55°C for 60 s.

[0059] S23. Secondary electrochemical corrosion: Use a mixed solution prepared by mixing a 2 mol / L hydrochloric acid solution and a 1 mol / L zinc sulfate solution in a ratio of 1:1 to perform secondary electrochemical corrosion treatment on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion at a solution temperature of 25°C, a corrosion current of 0.5 A / cm 2 and a frequency of 45 Hz for 5 s.

[0060] S24. Secondary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 3% to perform secondary chemical corrosion treatment on the aluminum foil after secondary electrochemical corrosion treatment at a solution temperature of 55°C for 60 s.

[0061] S25. Tertiary electrochemical corrosion: Use a 1 mol / L chlorine-containing etching solution prepared by mixing a hydrochloric acid solution, a potassium chloride solution, a titanium trichloride solution, and an ammonium chloride solution to perform electrochemical corrosion treatment on the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments at a solution temperature of 35°C, a corrosion current of 0.2 A / cm 2 and a frequency of 35 Hz for 5 s.

[0062] S30. Post-treatment: Use a zinc sulfate solution with a mass percentage concentration of 1% to perform a primary post-treatment on the aluminum foil after hole drilling at a solution temperature of 35°C for 65 s; Then, using a phosphorus-containing salt solution with a mass percentage concentration of 3% and composed of a mixture of ammonium dihydrogen phosphate solution and trisodium phosphate solution, and at a solution temperature of 70°C, the aluminum foil after the first post-treatment is subjected to a second post-treatment for 65 s; Then, using an ammonium salt solution with a mass percentage concentration of 3% and composed of a mixture of ammonium adipate solution and diammonium hydrogen phosphate solution, and at a solution temperature of 55°C, a current of 2 A, and a voltage of 0.2 V, the aluminum foil after the second post-treatment is subjected to a third post-treatment for 15 s.

[0063] S40. Cleaning. After the post-treatment of the aluminum foil is completed using 3 - 6 water tanks, the water on part of the aluminum foil is scraped dry with a squeegee.

[0064] S50. Drying. The cleaned aluminum foil is subjected to multi-stage drying, which specifically includes the following steps: S51. Primary drying. Using a drying temperature of 200°C, the cleaned aluminum foil is dried for 1 min; S52. Secondary drying. Using a drying temperature of 350°C, the aluminum foil after the primary drying is dried again for 3 min; S53. Tertiary drying. Using a drying temperature of 200°C, the aluminum foil after the secondary drying is dried again for 3 min to obtain an electrochemical current collector.

[0065] Example 3: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment. Using a weak acid degreasing solution composed of a mixture of a citric acid solution with a mass percentage concentration of 0.1% and an oxalic acid solution with a mass percentage concentration of 0.1% in a ratio of 1:1, and at a solution temperature of 55°C, the aluminum foil with a thickness of 20 μm is subjected to degreasing treatment. Then, using an ammonium dihydrogen phosphate solution with a mass percentage concentration of 0.1% of phosphorus-containing salt, and at a solution temperature of 70°C, the aluminum foil is subjected to anti-passivation treatment.

[0066] S20. Hole drilling. Using multiple alternating electrochemical corrosion and chemical corrosion, the aluminum foil after pretreatment is subjected to corrosion hole drilling; specifically including the following steps: S21. Primary electrochemical corrosion. Using a chloride ion etching solution composed of a mixture of a 1 mol / L hydrochloric acid solution and a 0.1 mol / L phosphoric acid solution in a ratio of 1:1, and at a solution temperature of 45°C, a corrosion current of 0.1 A / cm 2 、and a frequency of 45 Hz, the aluminum foil after pretreatment is subjected to electrochemical corrosion treatment for 7 s.

[0067] S22, Primary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 0.1% at a solution temperature of 35°C to perform chemical corrosion treatment on the aluminum foil after primary electrochemical corrosion treatment for 20 s.

[0068] S23, Secondary electrochemical corrosion: Use a mixed solution formed by mixing a 0.1 mol / L hydrochloric acid solution and a 0.1 mol / L zinc sulfate solution in a ratio of 1:1 at a solution temperature of 35°C and a corrosion current of 0.1 A / cm 2 and a frequency of 25 Hz to perform secondary electrochemical corrosion treatment on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion for 7 s.

[0069] S24, Secondary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 0.1% at a solution temperature of 35°C to perform secondary chemical corrosion treatment on the aluminum foil after secondary electrochemical corrosion treatment for 20 s.

[0070] S25, Tertiary electrochemical corrosion: Use a chlorine-containing etching solution of 0.1 mol / L formed by mixing a hydrochloric acid solution and a titanium trichloride solution at a solution temperature of 55°C and a corrosion current of 0.05 A / cm 2 and a frequency of 15 Hz to perform electrochemical corrosion treatment on the aluminum foil after two alternating treatments of electrochemical corrosion and chemical corrosion for 7 s.

[0071] S30, Post-treatment: Use a zinc sulfate solution with a mass percentage concentration of 0.1% at a solution temperature of 65°C to perform a primary post-treatment on the perforated aluminum foil for 20 s; Then, use an ammonium dihydrogen phosphate solution with a mass percentage concentration of phosphorus salt of 0.1% at a solution temperature of 35°C to perform a secondary post-treatment on the aluminum foil after the primary post-treatment for 20 s; Then, use an ammonium adipate solution with a mass percentage concentration of ammonia salt of 2% at a solution temperature of 30°C, a current of 2 A, and a voltage of 0.2 V to perform a tertiary post-treatment on the aluminum foil after the secondary post-treatment for 5 s.

[0072] S40, Cleaning: Use 3 - 6 water tanks to clean the aluminum foil after post-treatment, and then use a wiper to scrape off the water on part of the aluminum foil.

[0073] S50, Drying: Perform multi-stage drying on the cleaned aluminum foil, specifically including the following steps: S51, Primary drying: Use a drying temperature of 80°C to dry the cleaned aluminum foil for 3 min; S52, Secondary drying: Use a drying temperature of 200°C to re-dry the aluminum foil after primary drying for 3 min; S53. Tertiary drying: Using a drying temperature of 80 °C, the aluminum foil after secondary drying is dried again for 3 minutes to obtain an electrochemical current collector.

[0074] Example 4: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: Using a weak acid degreasing solution formed by mixing a citric acid solution with a mass percentage concentration of 1% and an oxalic acid solution with a mass percentage concentration of 1% in a ratio of 1:1, the aluminum foil with a thickness of 20 μm is degreased at a solution temperature of 45 °C. Then, using a passivation solution to prevent over-degreasing formed by mixing an ammonium dihydrogen phosphate solution and a sodium dihydrogen phosphate solution, with a mass percentage concentration of phosphorus salt of 1%, the aluminum foil is passivated at a solution temperature of 50 °C.

[0075] S20. Hole distribution: Using alternating electrochemical corrosion and chemical corrosion multiple times, the aluminum foil after pretreatment is corroded to form holes; specifically including the following steps: S21. Primary electrochemical corrosion: Using a chloride ion etching solution formed by mixing a 3.5 mol / L hydrochloric acid solution and a 0.5 mol / L phosphoric acid solution in a ratio of 1:1, at a solution temperature of 40 °C, a corrosion current of 0.5 A / cm 2 and a frequency of 60 Hz, the aluminum foil after pretreatment is electrochemically corroded for 10 seconds.

[0076] S22. Primary chemical corrosion: Using a phosphoric acid solution with a mass percentage concentration of 1%, at a solution temperature of 45 °C, the aluminum foil after primary electrochemical corrosion is chemically corroded for 40 seconds.

[0077] S23. Secondary electrochemical corrosion: Using a mixed solution formed by mixing a 1 mol / L hydrochloric acid solution and a 0.5 mol / L zinc sulfate solution in a ratio of 1:1, at a solution temperature of 30 °C, a corrosion current of 0.3 A / cm 2 and a frequency of 35 Hz, the aluminum foil after primary electrochemical corrosion and primary chemical corrosion is electrochemically corroded again for 10 seconds.

[0078] S24. Secondary chemical corrosion: Using a phosphoric acid solution with a mass percentage concentration of 1%, at a solution temperature of 45 °C, the aluminum foil after secondary electrochemical corrosion is chemically corroded again for 40 seconds.

[0079] S25. Tertiary electrochemical corrosion: Using a 0.5 mol / L chlorine-containing etching solution formed by mixing a potassium chloride solution and a titanium trichloride solution, at a solution temperature of 45 °C, a corrosion current of 0.1 A / cm2 Under the condition of a frequency of 25 Hz, the aluminum foil after being alternately treated by two - step electrochemical corrosion and chemical corrosion is subjected to electrochemical corrosion treatment for 10 s.

[0080] S30. Post - treatment: Using a zinc sulfate solution with a mass percentage concentration of 0.5%, at a solution temperature of 50 °C, the perforated aluminum foil is subjected to a first post - treatment for 40 s. Then, using a phosphorus - containing salt solution with a mass percentage concentration of 1% and composed of a mixture of ammonium dihydrogen phosphate solution and trisodium phosphate solution, at a solution temperature of 50 °C, the aluminum foil after the first post - treatment is subjected to a second post - treatment for 40 s. Then, using an ammonium adipate solution with a mass percentage concentration of 1%, at a solution temperature of 40 °C, a current of 2 A, and a voltage of 0.2 V, the aluminum foil after the second post - treatment is subjected to a third post - treatment for 10 s.

[0081] S40. Cleaning: After the post - treatment of the aluminum foil is completed, it is cleaned using 3 - 6 water tanks, and then the water on part of the aluminum foil is scraped dry with a water - scraping rod.

[0082] S50. Drying: The cleaned aluminum foil is subjected to multi - stage drying, which specifically includes the following steps: S51. First - stage drying: Using a drying temperature of 150 °C, the cleaned aluminum foil is dried for 3 min. S52. Second - stage drying: Using a drying temperature of 250 °C, the aluminum foil after the first - stage drying is dried again for 2 min. S53. Third - stage drying: Using a drying temperature of 150 °C, the aluminum foil after the second - stage drying is dried again for 2 min to obtain the electrochemical current collector.

[0083] Example 5: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: Using a weak acid degreasing solution composed of a citric acid solution with a mass percentage concentration of 2% and an oxalic acid solution with a mass percentage concentration of 2% in a ratio of 1:1, at a solution temperature of 45 °C, the aluminum foil with a thickness of 22 μm is subjected to degreasing treatment. Then, using a trisodium phosphate solution with a mass percentage concentration of 2% of phosphorus - containing salt, at a solution temperature of 50 °C, the aluminum foil is subjected to passivation prevention treatment.

[0084] S20. Perforation: Using multiple alternating electrochemical corrosion and chemical corrosion to corrode and perforate the aluminum foil after pretreatment; specifically, it includes the following steps: S21. Primary electrochemical corrosion: Using a chloride ion etching solution prepared by mixing a 2 mol / L hydrochloric acid solution and a 0.3 mol / L phosphoric acid solution in a ratio of 1:1, under the conditions of a solution temperature of 40°C, a corrosion current of 0.3 A / cm 2 and a frequency of 50 Hz, perform electrochemical corrosion treatment on the pre-treated aluminum foil for 5 s.

[0085] S22. Primary chemical corrosion: Using a 2% by mass phosphoric acid solution, at a solution temperature of 45°C, perform chemical corrosion treatment on the aluminum foil after primary electrochemical corrosion for 40 s.

[0086] S23. Secondary electrochemical corrosion: Using a mixed solution prepared by mixing a 0.7 mol / L hydrochloric acid solution and a 0.3 mol / L zinc sulfate solution in a ratio of 1:1, under the conditions of a solution temperature of 30°C, a corrosion current of 0.3 A / cm 2 and a frequency of 35 Hz, perform re-electrochemical corrosion treatment on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion for 10 s.

[0087] S24. Secondary chemical corrosion: Using a 2% by mass phosphoric acid solution, at a solution temperature of 45°C, perform re-chemical corrosion treatment on the aluminum foil after re-electrochemical corrosion for 40 s.

[0088] S25. Tertiary electrochemical corrosion: Using a 0.5 mol / L chlorine-containing etching solution prepared by mixing a hydrochloric acid solution and a titanium tetrachloride solution, under the conditions of a solution temperature of 45°C, a corrosion current of 0.12 A / cm 2 and a frequency of 25 Hz, perform electrochemical corrosion treatment on the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments for 10 s.

[0089] S30. Post-treatment: Using a 0.5% by mass zinc sulfate solution, at a solution temperature of 50°C, perform a first post-treatment on the perforated aluminum foil for 45 s; Then, using a phosphorus-containing salt solution with a mass percentage concentration of 1.5% prepared by mixing a diammonium hydrogen phosphate solution and a trisodium phosphate solution, at a solution temperature of 50°C, perform a second post-treatment on the aluminum foil after the first post-treatment for 45 s; Then, using a 1.5% by mass ammonium adipate solution, under the conditions of a solution temperature of 45°C, a current of 2 A, and a voltage of 0.2 V, perform a third post-treatment on the aluminum foil after the second post-treatment for 10 s.

[0090] S40. Cleaning: After cleaning the aluminum foil after post-treatment using 3 - 6 water tanks, use a squeegee to scrape off the water on part of the aluminum foil.

[0091] S50. Drying: The cleaned aluminum foil is dried in multiple stages, specifically including the following steps: S51. Primary drying: The cleaned aluminum foil is dried at a drying temperature of 150 °C for 3 minutes. S52. Secondary drying: The aluminum foil after primary drying is dried again at a drying temperature of 250 °C for 2 minutes. S53. Tertiary drying: The aluminum foil after secondary drying is dried again at a drying temperature of 150 °C for 2 minutes to obtain the electrochemical current collector.

[0092] Example 6: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: The aluminum foil with a thickness of 22 μm is degreased using a weak acid degreasing solution prepared by mixing a citric acid solution with a mass percentage concentration of 1.5% and an oxalic acid solution with a mass percentage concentration of 1.5% in a ratio of 1:1 at a solution temperature of 45 °C. Then, the aluminum foil is passivation-prevented using a sodium dihydrogen phosphate solution with a mass percentage concentration of phosphorus salt of 1.5% at a solution temperature of 50 °C.

[0093] S20. Hole formation: The pretreated aluminum foil is corroded to form holes by alternately performing multiple electrochemical corrosions and chemical corrosions; specifically including the following steps: S21. Primary electrochemical corrosion: The pretreated aluminum foil is electrochemically corroded using a chloride ion etching solution prepared by mixing a hydrochloric acid solution with a concentration of 4 mol / L and a phosphoric acid solution with a concentration of 0.8 mol / L in a ratio of 1:1 at a solution temperature of 40 °C, a corrosion current of 0.5 A / cm 2 , and a frequency of 55 Hz for 8 seconds.

[0094] S22. Primary chemical corrosion: The aluminum foil after primary electrochemical corrosion is chemically corroded using a phosphoric acid solution with a mass percentage concentration of 1.5% at a solution temperature of 45 °C for 40 seconds.

[0095] S23. Secondary electrochemical corrosion: The aluminum foil after primary electrochemical corrosion and primary chemical corrosion is electrochemically corroded again using a mixed solution prepared by mixing a hydrochloric acid solution with a concentration of 1.5 mol / L and a zinc sulfate solution with a concentration of 0.5 mol / L in a ratio of 1:1 at a solution temperature of 30 °C, a corrosion current of 0.30 A / cm 2 , and a frequency of 35 Hz for 10 seconds.

[0096] S24. Secondary 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 secondary electrochemical etching treatment is subjected to a secondary chemical etching treatment for 40 s.

[0097] S25. Tertiary electrochemical etching: Using a 0.5 mol / L chlorine-containing etching solution composed of a hydrochloric acid solution, a potassium chloride solution, and an ammonium chloride solution, at a solution temperature of 45°C and an etching current of 0.1 A / cm 2 and a frequency of 25 Hz, the aluminum foil after the alternating treatment of two electrochemical etching and chemical etching is subjected to an electrochemical etching treatment for 15 s.

[0098] S30. Post-treatment: Using a zinc sulfate solution with a mass percentage concentration of 0.8%, at a solution temperature of 50°C, the aluminum foil after pore drilling is subjected to a primary post-treatment for 45 s; Then, using a phosphorus-containing salt solution with a mass percentage concentration of 1.5% composed of an ammonium dihydrogen phosphate solution and a trisodium phosphate solution, at a solution temperature of 50°C, the aluminum foil after the primary post-treatment is subjected to a secondary post-treatment for 45 s; Then, using an ammonium salt solution with a mass percentage concentration of 1.5% composed of an ammonium adipate solution and an ammonium dihydrogen phosphate solution, at a solution temperature of 45°C, a current of 2 A, and a voltage of 0.2 V, the aluminum foil after the secondary post-treatment is subjected to a tertiary post-treatment for 10 s.

[0099] S40. Cleaning: After the aluminum foil after the post-treatment is cleaned using 3 - 6 water tanks, a water scraping rod is used to scrape off the water on part of the aluminum foil.

[0100] S50. Drying: The aluminum foil after cleaning is subjected to multi-stage drying, specifically including the following steps: S51. Primary drying: Using a drying temperature of 150°C, the aluminum foil after cleaning is dried for 3 min; S52. Secondary drying: Using a drying temperature of 250°C, the aluminum foil after the primary drying is dried again for 2 min; S53. Tertiary drying: Using a drying temperature of 150°C, the aluminum foil after the secondary drying is dried again for 2 min to obtain the electrochemical current collector.

[0101] Example 7: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: Use a weak acid degreasing solution prepared by mixing a citric acid solution with a mass percentage concentration of 0.8% and an oxalic acid solution with a mass percentage concentration of 0.8% in a ratio of 1:1. Degrease the aluminum foil with a thickness of 30 μm at a solution temperature of 45°C. Then, use a sodium dihydrogen phosphate solution containing 0.8% by mass of phosphorus salt to passivate the aluminum foil at a solution temperature of 50°C.

[0102] S20. Hole drilling: Use multiple alternating electrochemical corrosion and chemical corrosion to etch holes in the pretreated aluminum foil; specifically including the following steps: S21. Primary electrochemical corrosion: Use a chloride ion etching solution prepared by mixing a 5 mol / L hydrochloric acid solution and a 0.5 mol / L phosphoric acid solution in a ratio of 1:1. Perform electrochemical corrosion treatment on the pretreated aluminum foil at a solution temperature of 40°C, a corrosion current of 0.5 A / cm 2 and a frequency of 55 Hz for 10 s.

[0103] S22. Primary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 0.8% to perform chemical corrosion treatment on the aluminum foil after primary electrochemical corrosion at a solution temperature of 45°C for 40 s.

[0104] S23. Secondary electrochemical corrosion: Use a mixed solution prepared by mixing a 0.8 mol / L hydrochloric acid solution and a 0.6 mol / L zinc sulfate solution in a ratio of 1:1. Perform secondary electrochemical corrosion treatment on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion at a solution temperature of 30°C, a corrosion current of 0.2 A / cm 2 and a frequency of 35 Hz for 12 s.

[0105] S24. Secondary chemical corrosion: Use a phosphoric acid solution with a mass percentage concentration of 0.8% to perform secondary chemical corrosion treatment on the aluminum foil after secondary electrochemical corrosion at a solution temperature of 45°C for 40 s.

[0106] S25. Tertiary electrochemical corrosion: Use a 0.8 mol / L chlorine-containing etching solution prepared by mixing a hydrochloric acid solution, a potassium chloride solution, and a titanium trichloride solution. Perform electrochemical corrosion treatment on the aluminum foil after two alternating electrochemical corrosion and chemical corrosion treatments at a solution temperature of 45°C, a corrosion current of 0.12 A / cm 2 and a frequency of 25 Hz for 17 s.

[0107] S30. Post-treatment: Use a zinc sulfate solution with a mass percentage concentration of 0.5% to perform a primary post-treatment on the hole-drilled aluminum foil at a solution temperature of 50°C for 45 s; Then, using a sodium phosphate solution with a mass percentage concentration of phosphorus salt of 1.2% and a solution temperature of 55°C, the aluminum foil after the first post-treatment is subjected to a second post-treatment for 45 s; Then, using an ammonium adipate solution with a mass percentage concentration of 1.2%, under the conditions of a solution temperature of 45°C, a current of 2 A, and a voltage of 0.2 V, the aluminum foil after the second post-treatment is subjected to a third post-treatment for 10 s.

[0108] S40. Cleaning: After the post-treatment of the aluminum foil is completed using 3 - 6 water tanks, the water on part of the aluminum foil is scraped dry with a water scraping rod.

[0109] S50. Drying: The cleaned aluminum foil is subjected to multi-stage drying, which specifically includes the following steps: S51. Primary drying: Using a drying temperature of 150°C, the cleaned aluminum foil is dried for 3 min; S52. Secondary drying: Using a drying temperature of 250°C, the aluminum foil after the primary drying is dried again for 2 min; S53. Tertiary drying: Using a drying temperature of 150°C, the aluminum foil after the secondary drying is dried again for 2 min to obtain an electrochemical current collector.

[0110] Example 8: This example provides a method for preparing an electrochemical current collector, including the following steps: S10. Pretreatment: Using a weak acid degreasing solution prepared by mixing a citric acid solution with a mass percentage concentration of 2.5% and an oxalic acid solution with a mass percentage concentration of 2.5% in a ratio of 1:1, the aluminum foil with a thickness of 30 μm is degreased at a solution temperature of 45°C. Then, using a passivation solution to prevent over-degreasing prepared by mixing a disodium hydrogen phosphate solution and a sodium phosphate solution, with a mass percentage concentration of phosphorus salt of 2.5%, the aluminum foil is passivated at a solution temperature of 50°C.

[0111] S20. Hole formation: Using multiple alternating electrochemical corrosion and chemical corrosion, the aluminum foil after pretreatment is corroded to form holes; specifically including the following steps: S21. Primary electrochemical corrosion: Using a chloride ion etching solution prepared by mixing a 5 mol / L hydrochloric acid solution and a 0.8 mol / L phosphoric acid solution in a ratio of 1:1, at a solution temperature of 40°C, a corrosion current of 0.5 A / cm 2 and a frequency of 55 Hz, the aluminum foil after pretreatment is electrochemically corroded for 12 s.

[0112] S22. Primary chemical corrosion: The aluminum foil after primary electrochemical corrosion is chemically corroded using a phosphoric acid solution with a mass percentage concentration of 2.5% at a solution temperature of 45°C for 40 s.

[0113] S23. Secondary electrochemical corrosion: The aluminum foil after primary electrochemical corrosion and primary chemical corrosion is re-electrochemically corroded using a mixed solution composed of a 1.8 mol / L hydrochloric acid solution and a 0.8 mol / L zinc sulfate solution in a ratio of 1:1 at a solution temperature of 30°C, a corrosion current of 0.3 A / cm 2 and a frequency of 35 Hz for 15 s.

[0114] S24. Secondary chemical corrosion: The aluminum foil after re-electrochemical corrosion is re-chemically corroded using a phosphoric acid solution with a mass percentage concentration of 2.5% at a solution temperature of 45°C for 40 s.

[0115] S25. Tertiary electrochemical corrosion: The aluminum foil after two alternating treatments of electrochemical corrosion and chemical corrosion is electrochemically corroded using a 0.8 mol / L chlorine-containing etching solution composed of a hydrochloric acid solution and an ammonium chloride solution at a solution temperature of 45°C, a corrosion current of 0.15 A / cm 2 and a frequency of 25 Hz for 20 s.

[0116] S30. Post-treatment: The aluminum foil after hole drilling is first post-treated using a zinc sulfate solution with a mass percentage concentration of 0.8% at a solution temperature of 50°C for 45 s; then, the aluminum foil after the first post-treatment is second post-treated using a phosphorus-containing salt solution with a mass percentage concentration of 2.5% composed of an ammonium dihydrogen phosphate solution and a trisodium phosphate solution at a solution temperature of 55°C for 45 s; then, the aluminum foil after the second post-treatment is third post-treated using an ammonia-containing salt solution with a mass percentage concentration of 2.5% composed of an ammonium adipate solution and an ammonium dihydrogen phosphate solution at a solution temperature of 45°C, a current of 2 A, and a voltage of 0.2 V for 10 s.

[0117] S40. Cleaning: After the post-treatment of the aluminum foil is completed, it is cleaned using 3 - 6 water tanks, and then the water on part of the aluminum foil is scraped dry using a wiper rod.

[0118] S50. Drying: The cleaned aluminum foil is dried in multiple stages, specifically including the following steps: S51. First-stage drying: The cleaned aluminum foil is dried at a drying temperature of 150°C for 3 min; S52. Secondary drying: The aluminum foil after primary drying is dried again at a drying temperature of 250 °C for 2 minutes. S53. Tertiary drying: The aluminum foil after secondary drying is dried again at a drying temperature of 150 °C for 2 minutes to obtain the electrochemical current collector.

[0119] The aluminum foil with holes in Example 4 was observed under SEM for the holes on its surface. For example: The aluminum foil after primary electrochemical corrosion was observed under SEM, and the results are as Figure 1 shown; it can be seen from Figure 1 that there are scattered and different-sized hole structures on the surface of the aluminum foil, with the pore diameter ranging from 1 μm to 3 μm and the pore size ranging from 2 μm to 15 μm.

[0120] The aluminum foil after secondary electrochemical corrosion was observed under SEM, and the results are as Figure 2 shown; it can be seen from Figure 2 that compared with Figure 1 , not only the original holes on the surface of the aluminum foil are deepened and enlarged, but also many smaller and finer holes are formed between the large holes.

[0121] The aluminum foil after tertiary electrochemical corrosion was observed under SEM, and the results are as Figure 3 shown; it can be seen from Figure 3 that compared with Figure 2 , there is no obvious change in the holes on the surface of the aluminum foil, only the internal part of the aluminum foil is slightly enlarged. And when the aluminum foil only after tertiary electrochemical corrosion was observed under SEM, the results are as Figure 4 shown, and it can be seen from Figure 4 that many fine and small holes are formed on the surface of the aluminum foil.

[0122] Thus, it can be seen that for the electrochemical current collector prepared by the above electrochemical current collector preparation method, the aluminum foil is corroded and perforated by alternately performing multiple electrochemical corrosions and chemical corrosions, which can make the holes on the surface of the aluminum foil smaller and finer, and there are more rivet structures in the hole layer. Furthermore, the slurry formulations 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, and thus effectively extending the service life of the electrochemical current collector.

[0123] Performance Test Etching Depth Test: The etched foils of the electrochemical current collectors prepared in Examples 1-8 were cut into foil pieces of 10 mm × 10 mm. The electrochemical current collectors of commercially available supercapacitors 1-4 were dissected and made into metallographic grinding tables. After pretreatment methods such as grinding - polishing - soaking - sputtering with gold, the etching depth was measured by an electron microscope. Peeling force test: The electrochemical etching foils prepared in Examples 1-8 were made into electrode sheets. The electrode sheets were folded, and a part was peeled off from the middle end of the electrode sheet so that the length of the electrode sheet adhered to the double-sided tape was (50±1) mm. One end of the steel plate without the adhered tape was vertically clamped in the fixture of the tensile testing machine, and the free end of the electrode sheet was vertically downward. After the equipment was zeroed, it was clamped into another fixture and continuously peeled at a rate of (300±10) mm / s; Internal resistance test: The electrochemical etching foils prepared in Examples 1-8 were made into electrode sheets. Electrodes with a size of 8mm×20mm were made into 2.7V 3.3F supercapacitors, and commercially available supercapacitors 1-4 were used to measure the internal resistance according to 6.4.1.4 in GB / T34870.1; 1000h life test: The electrochemical etching foils prepared in Examples 1-8 were made into electrode sheets. Electrodes with a size of 8mm×20mm were made into 2.7V 3.3F supercapacitors, and commercially available supercapacitors 1-4 were placed in a high-temperature test chamber with a set temperature of 85±2°C for 1000h of storage time, and then placed at room temperature for 24h. The internal resistance was measured according to 6.4.1.4 in GB / T34870.1.

[0124] Using the above test methods, the 2.7V 3.3F supercapacitors made of the electrochemical current collectors in Examples 1-8 and commercially available 2.7V 3.3F supercapacitors were tested respectively. The measured etching depths, peeling strengths, internal resistances, and 1000h high-temperature life results are shown in Table 1.

[0125] Table 1 Performance parameter table of each test example

[0126] As can be seen from Table 1, compared with the current collectors in commercially available supercapacitors, the electrochemical current collectors prepared by processing aluminum foils with a thickness of 18μm - 30μm in Examples 1-8 effectively deepen the etching depth on the surface of the current collector, can be applied to supercapacitors, effectively increase the peeling strength and service life of supercapacitors, and reduce the internal resistance of supercapacitors.

[0127] The above content is only an example and explanation of the structure of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation of the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can be made, and these obvious replacement forms all belong to the protection scope 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, using multiple electrochemical etching and chemical etching alternately to etch and arrange holes on the pre-treated aluminum foil; Post-treatment, after the aluminum foil with holes corroded is post-treated with zinc sulfate solution and phosphorus salt solution, the aluminum foil after the initial post-treatment 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 primary electrochemical etching; Secondary electrochemical corrosion, using a mixture of hydrochloric acid solution and zinc sulfate solution, to perform electrochemical corrosion treatment again on the aluminum foil after primary electrochemical corrosion and primary chemical corrosion; Secondary chemical etching uses phosphoric acid solution to chemically etch the aluminum foil after the second electrochemical etching treatment. The three-stage 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, characterized in that: 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-70Hz; corrosion time is 5s -12s.

3. The method for preparing an electrochemical current collector according to claim 1, characterized in that: In the primary chemical corrosion step and the secondary chemical corrosion step, 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 a corrosion time of 20s-60s.

4. The method for preparing an electrochemical current collector according to claim 1, characterized in that: In the secondary electrochemical corrosion step, the mixed solution is a mixture of 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-45Hz; corrosion time is 5s-15s.

5. The method for preparing an electrochemical current collector according to claim 1, characterized in that: In the three-stage electrochemical corrosion 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 -35Hz, and corrosion time is 5s-20s.

6. The method for preparing an electrochemical current collector according to claim 1, characterized in that: 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, characterized in that: 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 diammonium phosphate solution, diammonium hydrogen phosphate solution, and trisodium phosphate solution. The temperature of the solution is 35°C-70°C; the post-treatment time is 20s-65s.

8. The method for preparing an electrochemical current collector according to claim 1, characterized in that: 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 diammonium dihydrogen phosphate solution, and 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, characterized in that: 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, characterized in that: In the pretreatment step, the anti-over-oil removal passivation solution is a mixture of one or more of diammonium dihydrogen phosphate solution, sodium dihydrogen phosphate solution, disodium hydrogen phosphate solution, and trisodium phosphate solution, and the mass percentage concentration of 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, characterized in that: The following steps are also included: Cleaning: using 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 drying temperature of 80°C-350°C; Wherein, the drying step comprises the following steps: First-stage drying: drying the cleaned aluminum foil at a drying temperature of 80°C-200°C for 1min-3min; Secondary drying: using a drying temperature of 200°C-350°C to dry the aluminum foil again after the primary drying, and the drying time is 2min-3min; 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 described in any one of claims 1 to 11.

13. Application of an electrochemical current collector 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 in a supercapacitor.

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