A high efficiency etching solution for alternating current etching of aluminum electrode foil

Abstract

The application relates to a high-efficiency etching solution for alternating-current etching of aluminum electrode foil, and belongs to the technical field of aluminum electrode foil processing. The formula of the high-efficiency etching solution is as follows: 30-40 parts of phosphoric acid, 8-15 parts of tartaric acid, 20-30 parts of a carboxymethyl chitosan solution, 0.1-0.5 parts of a polyaniline / graphene oxide quantum dot composite material, 0.1-0.2 parts of ammonium fluoride, 0.01-0.1 parts of sodium dodecyl diphenyl ether disulfonate and 40-60 parts of deionized water. Through the synergistic effect of multiple components in the formula, the synchronous improvement of etching efficiency and controllability of the morphology is finally realized, so that high-quality etching aluminum foil with high specific capacitance and consistent electrical performance is prepared.

Description

Technical Field

[0001] This invention belongs to the field of aluminum electrode foil processing technology, and relates to a high-efficiency etching solution for alternating current etching of aluminum electrode foil. Background Technology

[0002] Aluminum foil, with its high conductivity, lightweight and cost advantages, has always been a key material for current collectors in energy storage devices. Surface treatment technology of aluminum foil, especially etching process, is crucial for improving the specific surface area and electrochemical performance of electrode foil.

[0003] In the field of chemical etching technology, to form a porous structure on the surface of aluminum foil to increase the specific surface area, traditional techniques generally employ etching systems based on strong inorganic acids. These systems primarily rely on H... + and Cl - The chemical and electrochemical corrosion caused by corrosive ions randomly induces pitting corrosion at weak points in the oxide film on the aluminum foil surface, thus forming corrosion pits.

[0004] To improve the uniformity of pit distribution and suppress excessive lateral corrosion, existing technologies typically add various organic compounds to the base acid solution. These polymeric additives mainly form a dynamic coating film on the aluminum foil surface through physical adsorption. Utilizing the differences in adsorption strength at different surface sites, they guide the etching initiation location to some extent and influence the viscosity and mass transfer process of the etching solution. However, this type of chemical etching scheme based on the synergy of traditional additives and strong acids still suffers from insufficient randomness and controllability of pit nucleation, and weak depth etching and morphology control mechanisms when facing the manufacturing requirements of high-performance, high-uniformity electrode foils.

[0005] Therefore, there is an urgent need to develop a high-efficiency etching solution for alternating current etching of aluminum electrode foil. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a highly efficient etching solution for alternating current etching of aluminum electrode foil.

[0007] The objective of this invention can be achieved through the following technical solutions: A high-efficiency etching solution for alternating current etching of aluminum electrode foil, wherein the high-efficiency etching solution is formulated as follows, by weight: 30-40 parts phosphoric acid, 8-15 parts tartaric acid, 20-30 parts carboxymethyl chitosan solution, 0.1-0.5 parts polyaniline / graphene oxide quantum dot composite material, 0.1-0.2 parts ammonium fluoride, 0.01-0.1 parts sodium dodecyl diphenyl ether disulfonate, and 40-60 parts deionized water.

[0008] As a preferred embodiment of the present invention, the preparation method of the polyaniline / graphene oxide quantum dot composite material is as follows: S2-1: Mix aniline monomer with graphene oxide quantum dot dispersion, add 1 M nitric acid to adjust the pH of the system to 2-4, add oxidant, stir in an ice-water bath at 4 ℃ for 2-4 h, centrifuge the mixture to collect the solid, wash with deionized water, and then vacuum dry at 60-80 ℃ for 12 h to obtain product A; S2-2: Product A and polyvinylpyrrolidone were added to deionized water and ultrasonically mixed for 1-2 h. Then, the mixture was freeze-dried at -30 to -40 °C for 12 h to obtain the polyaniline / graphene oxide quantum dot composite material.

[0009] As a preferred embodiment of the present invention, the mass ratio of aniline monomer to graphene oxide quantum dots in S2-1 is (50~100):1.

[0010] As a preferred embodiment of the present invention, the oxidant in S2-1 is one or more of ammonium persulfate, potassium persulfate, ferric chloride, or hydrogen peroxide.

[0011] As a preferred embodiment of the present invention, the molar ratio of oxidant to aniline monomer in S2-1 is (0.5~1.5):1.

[0012] As a preferred embodiment of the present invention, the mass ratio of product A to polyvinylpyrrolidone in S2-2 is (8~10):1.

[0013] As a preferred embodiment of the present invention, the ultrasonic power in S2-2 is 50~100 W.

[0014] As a preferred embodiment of the present invention, the concentration of the carboxymethyl chitosan solution is 0.1~0.3 M.

[0015] In a preferred embodiment of the present invention, the mass fraction of phosphoric acid is 60-70%.

[0016] A method for preparing a high-efficiency etching solution for alternating current etching of aluminum electrode foil, the method comprising the following steps: S10-1: Mix phosphoric acid with half the mass of deionized water and stir for 10-30 min. While stirring, add tartaric acid and ammonium fluoride in sequence and continue stirring for 30-60 min to obtain mixture B. S10-2: Mix carboxymethyl chitosan solution with sodium dodecyl diphenyl ether disulfonate and stir for 30-60 min to obtain mixture C; S10-3: Add the polyaniline / graphene oxide quantum dot composite material to the remaining deionized water and ultrasonically disperse for 1-2 h to obtain dispersion D; S10-4: Add mixture C and dispersion D to mixture B under continuous stirring, and continue stirring for 1~2 h to obtain the high-efficiency etching solution.

[0017] In the polyaniline / graphene oxide quantum dot composite material, the polyaniline segments adsorb onto the aluminum foil surface through their benzene rings and quinone structures. This adsorption dynamically alters the electric double layer structure at the solid-liquid interface, slightly adjusting the local proton concentration and transport rate in the microscopic region at the etch pit tip. This affects the balance between local dissolution and regeneration of the alumina film, promoting a smoother advance of the etching front. The adsorbed layer can also act as a fine-tuner of the interface dielectric properties at the microscopic level, helping to homogenize the high-field region at the bottom of the etch pit, suppressing random and severe breakdown caused by electric field concentration, and making the etch pit growth direction more consistent.

[0018] Graphene oxide quantum dots, with their ultra-small size and abundant oxygen-containing functional groups on the surface, can penetrate deep into etching pits and growth fronts where traditional macromolecules are difficult to access, interacting weakly with etching products and effectively reducing Al. 3+ The energy barrier that allows reactants to detach from the pore wall and diffuse outward prevents pore blockage caused by product accumulation. The oxygen-containing groups on the quantum dot surface can form a dynamic network with tartrate complex anions and carboxymethyl chitosan molecular chains in the etching solution, optimizing the efficiency of reactant inward transport and product outward discharge, thereby forming a tunnel structure with a high aspect ratio and smooth pore walls.

[0019] After being encapsulated with polyvinylpyrrolidone, the composite material forms a hydrophilic polymer layer on its surface. This layer effectively prevents the composite material from agglomerating and settling in the high-ionic-strength acidic etching solution through steric hindrance, ensuring its stable dispersion. The interface modulation of polyaniline makes the initiation of etch pits more uniform, while the mass transfer optimization of graphene oxide quantum dots ensures the depth growth of the etch pits. The synergy of these two factors ultimately leads to the formation of an array of etch pits with narrow pore size distribution, high aspect ratio, and regular inner walls, providing an excellent substrate for subsequent formation processes. This results in improved specific capacitance and performance consistency of the etched aluminum foil.

[0020] Tartaric acid can react with Al generated during etching. 3+ Forming a complex, the Al within the channels 3+ The tartaric acid molecules can be adsorbed onto the surface of the aluminum foil and the inner wall of the etching pits, inhibiting the lateral expansion of the etching reaction through steric hindrance and guiding the longitudinal growth of the pits, thereby increasing the depth-to-diameter ratio of the pits. Furthermore, it forms a buffer pair with phosphoric acid, which helps stabilize the pH value during the etching process.

[0021] Carboxymethyl chitosan polymer chains can form a dynamic adsorption film on the surface of aluminum foil. This film exhibits weak adsorption at defects and grain boundaries with higher surface energy, while adsorption is stronger on intact crystal faces. This differential adsorption effect forces the etching reaction to preferentially initiate at sites with weak film coverage, thereby guiding the uniform nucleation and spatial distribution of etching pits (hole nuclei). In addition, it slightly increases the viscosity of the system, which helps to make the etching process smoother and more controllable.

[0022] Trace amounts of F in ammonium fluoride - It can form an AlF3 conversion layer on the aluminum surface. This layer undergoes uneven localized cracking under alternating current, thus providing a large number of uniform initial etch nuclei. This is the key to improving the uniformity and density of etch pit distribution, solving the problem of traditional Cl... - The problem of random nucleation in the system.

[0023] Sodium dodecyl diphenyl ether disulfonate can reduce the surface tension of the etching solution, allowing it to fully wet the aluminum foil surface and penetrate into the micro-etch pits, ensuring complete contact at the reaction interface. It can also promptly remove hydrogen microbubbles generated by etching side reactions, preventing gas blockage and ensuring continuous growth of the etch pits. Furthermore, it interacts with carboxymethyl chitosan to form a denser and more ordered composite adsorption interface layer.

[0024] The beneficial effects of this invention are: In this invention, ammonium fluoride and carboxymethyl chitosan synergistically act as etching templates and spatial screening agents, respectively, guiding the formation of high-density, uniformly distributed pit nuclei. Tartaric acid removes pore products through strong complexation and inhibits lateral corrosion through adsorption; surfactants ensure efficient mass transfer, and the two work synergistically to drive the formation of high aspect ratio tunnel pores. The polyaniline / graphene oxide quantum dot composite material further homogenizes the interface process at the nanoscale. Polyaniline fine-tunes the reaction environment at the etching front through adsorption; graphene oxide quantum dots, with their ultra-small size and abundant functional groups, penetrate deep into the pores to improve wettability and dynamically connect other components to construct a nanoscale mass transfer network; the combination of the two enables in-situ fine control of the interface process, effectively homogenizing pit growth. The synergistic effect of multiple components ultimately achieves a simultaneous improvement in etching efficiency and morphology controllability, thereby producing high-quality etched aluminum foil with high specific capacitance and consistent electrical properties. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0026] It should be noted that, unless otherwise specified, the present invention does not specifically limit the source of the raw materials used in the following embodiments. Commercially available products or products prepared by conventional preparation methods that are well known to those skilled in the art can be used. Experimental methods that do not specify specific conditions are all conventional methods and conventional conditions well known in the art. Example 1

[0027] A high-efficiency etching solution for alternating current etching of aluminum electrode foil, wherein the high-efficiency etching solution is formulated as follows (by weight): 35 parts 65% phosphoric acid, 12 parts tartaric acid, 25 parts 0.2 M carboxymethyl chitosan solution, 0.3 parts polyaniline / graphene oxide quantum dot composite material, 0.15 parts ammonium fluoride, 0.05 parts sodium dodecyl diphenyl ether disulfonate, and 50 parts deionized water.

[0028] The preparation method of the polyaniline / graphene oxide quantum dot composite material is as follows: S2-1: Aniline monomer and graphene oxide quantum dot dispersion were mixed, wherein the mass ratio of aniline monomer to graphene oxide quantum dots was 75:1. 1 M nitric acid was added to adjust the pH of the system to 3. Ammonium persulfate was added, and the molar ratio of ammonium persulfate to aniline monomer was 1:1. The mixture was stirred in an ice-water bath at 4 ℃ for 3 h. The mixture was centrifuged to separate the solids, washed with deionized water, and then vacuum dried at 70 ℃ for 12 h to obtain product A. S2-2: Product A and polyvinylpyrrolidone were mixed at a mass ratio of 9:1 and added to deionized water. The mixture was ultrasonically mixed for 1.5 h with an ultrasonic power of 75 W, and then freeze-dried at -35 ℃ for 12 h to obtain the polyaniline / graphene oxide quantum dot composite material.

[0029] A method for preparing a high-efficiency etching solution for alternating current etching of aluminum electrode foil, the method comprising the following steps: S10-1: Mix phosphoric acid with half the mass of deionized water and stir for 20 min. While stirring, add tartaric acid and ammonium fluoride in sequence and continue stirring for 45 min to obtain mixture B. S10-2: Mix carboxymethyl chitosan solution with sodium dodecyl diphenyl ether disulfonate and stir for 45 min to obtain mixture C; S10-3: Add the polyaniline / graphene oxide quantum dot composite material to the remaining deionized water and ultrasonically disperse for 1.5 h to obtain dispersion D; S10-4: Add mixture C and dispersion D to mixture B under continuous stirring, and continue stirring for 1.5 h to obtain the high-efficiency etching solution. Example 2

[0030] A high-efficiency etching solution for alternating current etching of aluminum electrode foil, the formulation of which is as follows (by weight): 30 parts 70% phosphoric acid, 8 parts tartaric acid, 20 parts 0.1 M carboxymethyl chitosan solution, 0.1 parts polyaniline / graphene oxide quantum dot composite material, 0.1 parts ammonium fluoride, 0.01 parts sodium dodecyl diphenyl ether disulfonate, and 40 parts deionized water.

[0031] The preparation method of the polyaniline / graphene oxide quantum dot composite material is as follows: S2-1: Aniline monomer and graphene oxide quantum dot dispersion were mixed, wherein the mass ratio of aniline monomer to graphene oxide quantum dots was 50:1. 1 M nitric acid was added to adjust the pH of the system to 2. Ammonium persulfate was added, and the molar ratio of ammonium persulfate to aniline monomer was 0.5:1. The mixture was stirred in an ice-water bath at 4 ℃ for 2 h. The mixture was centrifuged to separate the solids, washed with deionized water, and then vacuum dried at 60 ℃ for 12 h to obtain product A. S2-2: Product A and polyvinylpyrrolidone were mixed at a mass ratio of 8:1 and added to deionized water. The mixture was ultrasonically mixed for 1 h with an ultrasonic power of 50 W. Then, it was freeze-dried at -30 °C for 12 h to obtain the polyaniline / graphene oxide quantum dot composite material.

[0032] A method for preparing a high-efficiency etching solution for alternating current etching of aluminum electrode foil, the method comprising the following steps: S10-1: Mix phosphoric acid with half the mass of deionized water and stir for 10 min. While stirring, add tartaric acid and ammonium fluoride in sequence and continue stirring for 30 min to obtain mixture B. S10-2: Mix carboxymethyl chitosan solution with sodium dodecyl diphenyl ether disulfonate and stir for 30 min to obtain mixture C; S10-3: Add the polyaniline / graphene oxide quantum dot composite material to the remaining deionized water and ultrasonically disperse for 1 hour to obtain dispersion D; S10-4: Add mixture C and dispersion D to mixture B under continuous stirring, and continue stirring for 1 h to obtain the high-efficiency etching solution. Example 3

[0033] A high-efficiency etching solution for alternating current etching of aluminum electrode foil, wherein the high-efficiency etching solution is formulated as follows (by weight): 40 parts 60% phosphoric acid, 15 parts tartaric acid, 30 parts 0.3 M carboxymethyl chitosan solution, 0.5 parts polyaniline / graphene oxide quantum dot composite material, 0.2 parts ammonium fluoride, 0.1 parts sodium dodecyl diphenyl ether disulfonate, and 60 parts deionized water.

[0034] The preparation method of the polyaniline / graphene oxide quantum dot composite material is as follows: S2-1: Aniline monomer and graphene oxide quantum dot dispersion were mixed, wherein the mass ratio of aniline monomer to graphene oxide quantum dots was 100:1. 1 M nitric acid was added to make the pH of the system 4. Ammonium persulfate was added, and the molar ratio of ammonium persulfate to aniline monomer was 1.5:1. The mixture was stirred in an ice-water bath at 4 ℃ for 4 h. The mixture was centrifuged to separate the solids, washed with deionized water, and then vacuum dried at 80 ℃ for 12 h to obtain product A. S2-2: Product A and polyvinylpyrrolidone were mixed at a mass ratio of 10:1 and added to deionized water. The mixture was ultrasonically mixed for 2 h at an ultrasonic power of 100 W, and then freeze-dried at -40 °C for 12 h to obtain the polyaniline / graphene oxide quantum dot composite material.

[0035] A method for preparing a high-efficiency etching solution for alternating current etching of aluminum electrode foil, the method comprising the following steps: S10-1: Mix phosphoric acid with half the mass of deionized water and stir for 30 min. While stirring, add tartaric acid and ammonium fluoride in sequence and continue stirring for 60 min to obtain mixture B. S10-2: Mix carboxymethyl chitosan solution with sodium dodecyl diphenyl ether disulfonate and stir for 60 min to obtain mixture C; S10-3: Add the polyaniline / graphene oxide quantum dot composite material to the remaining deionized water and ultrasonically disperse for 2 hours to obtain dispersion D; S10-4: Add mixture C and dispersion D to mixture B under continuous stirring, and continue stirring for 2 h to obtain the high-efficiency etching solution.

[0036] Comparative Example 1 The difference between this comparative example and Example 1 is that the polyaniline / graphene oxide quantum dot composite material is not added; otherwise, they are the same as in Example 1.

[0037] Comparative Example 2 The difference between this comparative example and Example 1 is that the preparation of the polyaniline / graphene oxide quantum dot composite material does not involve step S2-2, while the rest is the same as in Example 1.

[0038] Comparative Example 3 The difference between this comparative example and Example 1 is that the polyaniline / graphene oxide quantum dot composite material is replaced by a mechanical mixture of polyaniline and graphene oxide quantum dots; otherwise, it is the same as Example 1.

[0039] Comparative Example 4 The difference between this comparative example and Example 1 is that ammonium fluoride is not added; otherwise, they are the same as in Example 1.

[0040] Comparative Example 5 The difference between this comparative example and Example 1 is that carboxymethyl chitosan solution is not added; otherwise, they are the same as in Example 1.

[0041] Performance testing A 30 μm thick high-purity aluminum foil was placed in the etching solution of the examples or comparative examples and etched at 50°C for 20 min. After etching, it was ultrasonically cleaned with deionized water and dried to obtain the etched foil. The surface and cross-sectional morphology of the etched aluminum foil were observed using a scanning electron microscope, and the number of etch pits per unit area (number / μm) was recorded. 2 The depth-to-opening diameter ratio of at least 20 representative pits was measured using cross-sectional SEM images.

[0042] The prepared etched foil was formed at 520V according to the SJ / T1140-2012 standard to obtain aluminum foil products, and the specific volume of each sample was measured using a specific volume tester. The specific experimental results are summarized in the table below.

[0043] As can be seen from the examples and comparative data, the etching solution prepared by the present invention has better etching efficiency, the surface pit density is significantly increased and high aspect ratio tunnel holes are formed, and the final aluminum foil product has better electrochemical performance.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are still within the scope of the present invention.

Claims

1. A high-efficiency etching solution for alternating current etching of aluminum electrode foil, characterized in that, The formulation of the high-efficiency etching solution is as follows, by weight: 30-40 parts phosphoric acid, 8-15 parts tartaric acid, 20-30 parts carboxymethyl chitosan solution, 0.1-0.5 parts polyaniline / graphene oxide quantum dot composite material, 0.1-0.2 parts ammonium fluoride, 0.01-0.1 parts sodium dodecyl diphenyl ether disulfonate, and 40-60 parts deionized water.

2. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 1, characterized in that, The preparation method of the polyaniline / graphene oxide quantum dot composite material is as follows: S2-1: Mix aniline monomer with graphene oxide quantum dot dispersion, add 1 M nitric acid to adjust the pH of the system to 2-4, add oxidant, stir in an ice-water bath at 4 ℃ for 2-4 h, centrifuge the mixture to collect the solid, wash with deionized water, and then vacuum dry at 60-80 ℃ for 12 h to obtain product A; S2-2: Product A and polyvinylpyrrolidone were added to deionized water and ultrasonically mixed for 1-2 h. Then, the mixture was freeze-dried at -30 to -40 °C for 12 h to obtain the polyaniline / graphene oxide quantum dot composite material.

3. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 2, characterized in that, The mass ratio of aniline monomer to graphene oxide quantum dots in S2-1 is (50~100):

1.

4. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 2, characterized in that, The oxidant in S2-1 is one or more of ammonium persulfate, potassium persulfate, ferric chloride, or hydrogen peroxide.

5. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 2, characterized in that, The molar ratio of oxidant to aniline monomer in S2-1 is (0.5~1.5):

1.

6. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 2, characterized in that, The mass ratio of product A to polyvinylpyrrolidone in S2-2 is (8~10):

1.

7. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 2, characterized in that, The ultrasonic power in S2-2 is 50~100 W.

8. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 1, characterized in that, The concentration of the carboxymethyl chitosan solution is 0.1~0.3 M.

9. The high-efficiency etching solution for alternating current etching of aluminum electrode foil according to claim 1, characterized in that, The mass fraction of the phosphoric acid is 60-70%.

10. A method for preparing a high-efficiency etching solution for alternating current etching of aluminum electrode foil as described in any one of claims 1 to 9, characterized in that, The preparation method includes the following steps. S10-1: Mix phosphoric acid with half the mass of deionized water and stir for 10-30 min. While stirring, add tartaric acid and ammonium fluoride in sequence and continue stirring for 30-60 min to obtain mixture B. S10-2: Mix carboxymethyl chitosan solution with sodium dodecyl diphenyl ether disulfonate and stir for 30-60 min to obtain mixture C; S10-3: Add the polyaniline / graphene oxide quantum dot composite material to the remaining deionized water and ultrasonically disperse for 1-2 hours to obtain dispersion D; S10-4: Add mixture C and dispersion D to mixture B under continuous stirring, and continue stirring for 1~2 h to obtain the high-efficiency etching solution.

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