Aluminum-based composite current collector with high corrosion resistance and high conductivity and preparation method thereof

Abstract

The application relates to the technical field of current collectors, in particular to an aluminum-based composite current collector with high corrosion resistance and high conductivity and a preparation method thereof. The aluminum-based composite current collector comprises, from the inside to the outside, a base film layer, aluminum-based layers deposited on the two surfaces of the base film layer, a zinc transition layer covering the surfaces of the aluminum-based layers, and a functional surface layer formed by coating modified coating on the surface of the zinc transition layer. The preparation steps comprise the following steps: step 1, pretreating the base film layer to obtain a pretreated base film; step 2, depositing aluminum layers on the two surfaces of the pretreated base film to form aluminum-based layers; step 3, forming a zinc transition layer on the surfaces of the aluminum-based layers; and step 4, coating modified coating on the surface of the zinc transition layer to form a functional surface layer, and obtaining the aluminum-based composite current collector after solidification treatment. The aluminum-based composite current collector prepared by the application has excellent heat resistance and solvent resistance, high overall mechanical properties, high tensile strength and good flexibility, and has the characteristics of light weight, and is suitable for complex working conditions of batteries and is suitable for high requirement electrochemical fields.

Description

Technical Field

[0001] This application relates to the field of current collector technology, and more specifically, to an aluminum-based composite current collector with high corrosion resistance and conductivity and its preparation method. Background Technology

[0002] In electrochemical energy storage devices such as lithium-ion and sodium-ion batteries, the current collector, as a key component carrying active materials and conducting current, directly affects the battery's cycle life, rate performance, and safety. Currently, commercially available positive electrode current collectors mainly use pure aluminum foil, but they face two major problems during long-term battery charge-discharge processes: first, the surface of the aluminum foil is easily corroded by HF generated by electrolyte decomposition, forming a loose oxide layer that increases contact resistance; second, under high-voltage conditions, aluminum-based current collectors are prone to electrochemical passivation, exacerbating battery polarization and causing capacity decay. The existing improvement technologies have obvious limitations: (1) Traditional carbon-coated aluminum foil attaches carbon materials to the aluminum surface through an adhesive. Although it can isolate the corrosive medium to a certain extent, the non-conductive nature of the adhesive leads to an increase in interfacial impedance, and the coating is weak and easy to fall off. (2) Although chromate passivation treatment can form a corrosion-resistant film, the use of hexavalent chromium poses serious environmental hazards. (3) Although single metal plating (such as nickel and zinc) can improve corrosion resistance, it has problems such as high interfacial impedance with the aluminum substrate, possible passivation under high voltage, or poor compatibility with some positive electrode materials, which affect battery performance. (4) Nanocarbon materials have poor dispersion stability in electrolyte, the coating process is difficult to achieve ultra-thin, dense and defect-free coatings, and there are high costs, which make it difficult to meet the needs of industrial production. With the development of high-voltage cathode materials, such as lithium-rich manganese-based and nickel-cobalt-manganese ternary materials, higher requirements have been placed on the corrosion resistance and conductivity of current collectors. Developing an aluminum-based composite current collector that combines excellent resistance to electrolyte corrosion, low interfacial impedance, and industrial feasibility has become a key technological breakthrough in solving the cycle stability problem of high-energy-density batteries. Summary of the Invention

[0003] To address the technical problems mentioned in the background section, this application provides an aluminum-based composite current collector with high corrosion resistance and conductivity, and its preparation method.

[0004] In a first aspect, this application provides an aluminum-based composite current collector with high corrosion resistance and conductivity, employing the following technical solution: A corrosion-resistant and highly conductive aluminum-based composite current collector comprises, from the inside out, a base film layer, an aluminum substrate deposited on both sides of the base film layer, a zinc transition layer covering the surface of the aluminum substrate, and a functional surface layer formed by curing a modified coating applied to the surface of the zinc transition layer. The base film layer is a polyethylene terephthalate, polypropylene, polyimide or polyamide insulating polymer film with a thickness of 2-10 μm; The aluminum substrate is formed by magnetron sputtering or vapor deposition, and the thickness of the aluminum substrate is controlled to be 0.5-5μm; The zinc transition layer is prepared by chemical deposition using a highly stable electroless zinc plating solution, and the thickness of the zinc transition layer is controlled to be 100-300 nm. The functional surface layer is formed by curing a modified coating, and the thickness of the functional surface layer is controlled to be 1-5 μm.

[0005] Preferably, the high-stability electroless zinc plating solution comprises zinc sulfate, sodium hypophosphite, a complexing agent, boric acid, a stabilizing agent, and deionized water, wherein the concentration of zinc sulfate is 20-40 g / L, the concentration of sodium hypophosphite is 25-50 g / L, the concentration of the complexing agent is 20-45 g / L, the concentration of boric acid is 10-20 g / L, the concentration of the stabilizing agent is 1-3 g / L, and the pH is adjusted to 9.0-10.5 with NaOH solution.

[0006] Preferably, the complexing agent is one or more of sodium citrate, hydroxyethylidene diphosphonic acid, and glycine.

[0007] The stabilizing agent is composed of cocamidopropyl betaine, cerium nitrate and thiourea in a mass ratio of 10-25:5-8:3-5.

[0008] Preferably, the preparation of the modified coating includes the following preparation steps: Step S1: Disperse vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate in N-methylpyrrolidone. Under nitrogen protection, add an initiator and react at 65-70°C for 6-8 hours to obtain a modified fluororesin prepolymer. Step S2: Add N-phenylmaleimide and trifluorochloroethylene to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, stir and react for 8-12 hours at a temperature of 70-75℃. After the reaction is completed, cool to room temperature, precipitate, filter, wash and dry to obtain the modified fluororesin. Step S3: After pretreatment, graphene and nickel powder are mixed with solvent, ball-milled and dispersed for 2-3 hours, then modified fluororesin is added and dispersed by high-speed shearing for 40-60 minutes to obtain modified coating.

[0009] Preferably, in step S1, the mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50-70:12-25:5-15:150-250.

[0010] Preferably, in step S2, the mass ratio of the modified fluororesin prepolymer, N-phenylmaleimide, and trifluorochloroethylene is 50-80:5-12:10-20.

[0011] Preferably, the mass ratio of graphene, nickel powder and modified fluororesin in step S3 is 1-5:5-8:80-100.

[0012] Secondly, this application also provides a method for preparing an aluminum-based composite current collector with high corrosion resistance and conductivity, comprising the following steps: Step 1: After cleaning to remove surface impurities, the base film layer is treated with plasma and then dried in a vacuum oven at 60-80℃ for 2-4 hours to obtain the pretreated base film. Step 2: Deposit aluminum layers on both sides of the pretreated base film using magnetron sputtering or vapor deposition to form an aluminum base layer; Step 3: After degreasing and acid-washing activation of the aluminum substrate surface, immerse it in a high-stability chemical zinc plating solution and react for 30-120 seconds. After the reaction is complete, rinse with deionized water and dry in an oven at 50-70℃ for 10-15 minutes to form a zinc transition layer. Step 4: Apply a modified coating to the surface of the zinc transition layer to form a functional surface layer. After curing, an aluminum-based composite current collector is obtained.

[0013] Preferably, the curing process in step 4 is as follows: curing at a temperature of 40-60℃ for 10-15 minutes, raising the temperature to 80-100℃ and curing for 10-12 minutes, and finally curing at 120-150℃ for 5-8 minutes.

[0014] In summary, this application has the following beneficial effects: This application utilizes the synergistic effect of zinc transition layer stabilizing agents to significantly improve the density and interfacial adhesion of the coating. Cerium nitrate in the stabilizing agent hydrolyzes to generate a CeO2 / hydroxide film, covering the pores on the zinc layer surface, while thiourea inhibits the excessive reduction of zinc ions through adsorption, refining the grain size. The synergistic effect of these two agents results in a uniform zinc transition layer thickness and reduced porosity, thereby enhancing the tensile strength and corrosion resistance of the zinc transition layer.

[0015] This application utilizes vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate as synthetic monomers to achieve synergistic effects through the structural characteristics of each monomer. Vinylidene fluoride, as the basic monomer of fluororesin, provides excellent chemical corrosion resistance, mechanical strength, and dielectric properties, laying the core performance foundation for modified fluororesin. The 2,3,4,5,6-pentafluorostyrene molecule contains a rigid benzene ring structure and polyfluorinated substituents. The benzene ring can enhance the rigidity and steric hindrance of the molecular chain, improving the heat resistance stability of the resin. The polyfluorinated substituents further strengthen the intermolecular forces, enhancing solvent resistance and chemical corrosion resistance. Trifluoroethyl methacrylate contains ester groups and trifluoromethyl groups. The ester groups can improve the compatibility of the resin with other components (such as graphene and nickel powder), improving the dispersion stability of the coating system. The trifluoromethyl groups further optimize weather resistance and solvent resistance by increasing the fluorine content. At the same time, its flexible segments can balance the rigidity of the molecular chain, avoiding the brittleness problem caused by excessive rigidity of the resin. The three components copolymerize to form complementary molecular chains, which significantly improves the heat resistance and solvent resistance of the modified fluororesin while maintaining the inherent excellent properties of fluororesin. This makes it more suitable for the complex environment faced by current collectors in battery systems, such as high temperature and electrolyte immersion.

[0016] By combining graphene and nickel powder and implementing targeted pretreatment, a synergistic system is constructed. Graphene, a two-dimensional sheet, has active sites introduced on its surface after argon plasma treatment, improving its dispersibility and resin compatibility. Nickel powder, a three-dimensional particle, is treated with a silane coupling agent to enhance its bonding force with the resin. The two form a conductive network of "sheet bridging - particle gap filling," filling the defects of a single filler. At the same time, graphene disperses stress, and nickel powder inhibits chain slippage, synergistically improving tensile strength and optimizing coating stability. After curing, the surface is defect-free with low volume swelling, achieving simultaneous enhancement of conductivity, mechanical properties, and corrosion resistance. Detailed Implementation

[0017] The present application will be further described in detail below with reference to the embodiments.

[0018] The polyethylene terephthalate insulating polymer film (thickness: 4.5 μm) used in the embodiments and comparative examples of this invention was purchased from Dongguan Wenxuan New Material Co., Ltd.; cocamidopropyl betaine was purchased from Shandong Jiaxu Chemical Co., Ltd.; cerium nitrate was purchased from Jinan Huijinchuan Trading Co., Ltd.; thiourea was purchased from Shandong Yaojia Chemical Co., Ltd.; 2,3,4,5,6-pentafluorostyrene was purchased from Shanghai Licas Industrial Co., Ltd.; trifluoroethyl methacrylate was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.; N-phenylmaleimide was purchased from Nantong Zhonghe Chemical New Material Co., Ltd.; trifluorochloroethylene was purchased from Shandong Xindongneng Chemical Co., Ltd.; graphene (particle size: 2000 mesh) was purchased from Hebei Guangtuo Welding Materials Co., Ltd.; nickel powder (particle size: 30000 mesh) was purchased from Nangong Xingjiu New Material Technology Co., Ltd.; and fluororesin (grade: FR-906) was purchased from Dongguan Zhangmutou Hengtai Plastic Raw Material Business Department.

[0019] Examples 1-3 and Comparative Examples 1-9 provide an aluminum-based composite current collector with high corrosion resistance and conductivity, and a method for preparing the same.

[0020] Example 1 A corrosion-resistant and highly conductive aluminum-based composite current collector comprises, from the inside out, a base film layer, aluminum substrates deposited on both sides of the base film layer, a zinc transition layer covering the surface of the aluminum substrate, and a functional surface layer formed by curing a modified coating applied to the surface of the zinc transition layer. The base film layer is a polyethylene terephthalate insulating polymer film; the aluminum substrate is formed by magnetron sputtering; the zinc transition layer is prepared by chemical deposition using a highly stable electroless zinc plating solution, with a thickness of 100 nm; and the functional surface layer is formed by curing a modified coating, with a thickness of 1 μm.

[0021] The high-stability electroless zinc plating solution includes zinc sulfate, sodium hypophosphite, glycine, boric acid, stabilizer, and deionized water. The concentrations of zinc sulfate, sodium hypophosphite, glycine, boric acid, and stabilizer are 20 g / L, 25 g / L, 20 g / L, 10 g / L, and 1 g / L. The pH is adjusted to 9.0 with NaOH solution. The stabilizer consists of cocamidopropyl betaine, cerium nitrate, and thiourea in a mass ratio of 10:5:3.

[0022] The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 0.8% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 100 rpm and 65°C for 6 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50:12:5:150. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 70°C for 8 hours at a stirring speed of 50 rpm. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 60°C for 10 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 50:5:10. Step S3: Place the graphene in a 100W plasma treatment instrument and treat it with argon plasma for 3 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 20 minutes. The ultrasonic power is 100W and the ultrasonic frequency is 40kHz. Dry it at 60℃ for 6 hours. The mass ratio of nickel powder, KH-550 and ethanol is 100:1:400. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 2 hours. Then add modified fluororesin and control the solid content to 30%. Under nitrogen protection, control the shear speed to 3000rpm and shear disperse for 40 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 1:5:80.

[0023] A method for preparing an aluminum-based composite current collector with high corrosion resistance and electrical conductivity includes the following preparation steps: Step 1: The base film layer is cleaned in an ultrasonic cleaner with a power of 200W and a frequency of 40kHz for 15 minutes using a 50wt% ethanol aqueous solution. The cleaned base film layer is then placed in a plasma treatment instrument with a vacuum of 5Pa and a power of 150W. A mixture of argon and oxygen with a volume ratio of 8:2 is introduced and treated for 2 minutes. After treatment, the base film layer is vacuum dried at 60℃ for 2 hours to obtain the pretreated base film. Step 2: Aluminum layers are deposited on both sides of the pretreated base film using magnetron sputtering. The sputtering power is controlled at 200W, the base film temperature is 40℃, and the deposition rate is 0.5nm / s. Aluminum layers with a thickness of 0.5μm are deposited on both sides of the base film to form an aluminum base layer. Step 3: Immerse the aluminum substrate in a NaOH solution with pH 10 at 50℃ for 3 minutes to degrease it. After degreasing, immerse it in an H2SO4 solution with pH 2 for 20 seconds. After removal, rinse with deionized water until neutral to obtain the activated sample. Immerse the activated sample in a high-stability electroless zinc plating solution, controlling the solid-liquid mass ratio of the activated sample to the high-stability electroless zinc plating solution to be 2:10. The temperature of the high-stability electroless zinc plating solution is 70℃. Adjust the pH to 5 with H2SO4 and soak for 30 seconds. After the reaction is complete, rinse with deionized water and dry in a 50℃ oven for 10 minutes to form a zinc transition layer. Step 4: Apply modified coating to the surface of zinc transition layer, control the coating speed to 1m / min, cure at 40℃ for 10min, raise the temperature to 80℃ and cure for 10min, and finally cure at 120℃ for 5min. After curing treatment, aluminum-based composite current collector is obtained.

[0024] Example 2 A corrosion-resistant and highly conductive aluminum-based composite current collector comprises, from the inside out, a base film layer, aluminum substrates deposited on both sides of the base film layer, a zinc transition layer covering the surface of the aluminum substrate, and a functional surface layer formed by curing a modified coating applied to the surface of the zinc transition layer. The base film layer is a polyethylene terephthalate insulating polymer film; the aluminum substrate is formed by magnetron sputtering; the zinc transition layer is prepared by chemical deposition using a highly stable electroless zinc plating solution, with a thickness of 200 nm; and the functional surface layer is formed by curing a modified coating, with a thickness of 3 μm.

[0025] The high-stability electroless zinc plating solution includes zinc sulfate, sodium hypophosphite, glycine, boric acid, stabilizing agent, and deionized water. The concentrations of zinc sulfate, sodium hypophosphite, glycine, boric acid, and stabilizing agent are 30 g / L, 40 g / L, 35 g / L, 15 g / L, and 2 g / L, respectively. The pH is adjusted to 10 with NaOH solution. The stabilizing agent consists of cocamidopropyl betaine, cerium nitrate, and thiourea in a mass ratio of 18:7:4.

[0026] The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 1% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 150 rpm and 68°C for 7 hours to obtain a modified fluororesin prepolymer. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 60:20:10:200. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 72°C and 800 rpm for 10 hours. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 65°C for 11 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 65:8:15. Step S3: Place the graphene in a 120W plasma treatment instrument and treat it with argon plasma for 4 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 30 minutes. The ultrasonic power is 110W and the ultrasonic frequency is 50kHz. Dry it at 70℃ for 7 hours. The mass ratio of nickel powder, KH-550 and ethanol is 110:1.5:450. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 2.5 hours. Then add modified fluororesin and control the solid content to 33%. Under nitrogen protection, control the shear speed to 3500 rpm and shear disperse for 50 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 3:7:90.

[0027] A method for preparing an aluminum-based composite current collector with high corrosion resistance and electrical conductivity includes the following preparation steps: Step 1: The base film layer is cleaned in an ultrasonic cleaner with a power of 250W and a frequency of 50kHz for 18 minutes using a 60wt% ethanol aqueous solution. The cleaned base film layer is then placed in a plasma treatment instrument with a vacuum of 8Pa and a power of 180W. A mixture of argon and oxygen with a volume ratio of 8:2 is introduced and treated for 2.5 minutes. After treatment, the base film layer is vacuum dried at 780℃ for 3 hours to obtain the pretreated base film. Step 2: Aluminum layers are deposited on both sides of the pretreated base film using magnetron sputtering. The sputtering power is controlled at 250W, the base film temperature is 45℃, and the deposition rate is 0.8nm / s. A 3μm thick aluminum layer is deposited on both sides of the base film to form an aluminum base layer. Step 3: Immerse the aluminum substrate in a NaOH solution with pH 10.5 at 55℃ for 4 minutes to degrease it. After degreasing, immerse it in an H2SO4 solution with pH 3 for 25 seconds. After removal, rinse with deionized water until neutral to obtain the activated sample. Immerse the activated sample in a high-stability electroless zinc plating solution, controlling the solid-liquid mass ratio of the activated sample to the high-stability electroless zinc plating solution to be 3:11. The temperature of the high-stability electroless zinc plating solution is 75℃. Adjust the pH to 5.5 with H2SO4 and immerse for 80 seconds to form a zinc transition layer. Rinse with deionized water 3 times and dry in a 60℃ oven for 12 minutes to form a zinc transition layer. Step 4: Apply modified coating to the surface of zinc transition layer, control the coating speed to 1.5 m / min, cure at 50℃ for 12 min, raise the temperature to 90℃ and cure for 11 min, and finally cure at 135℃ for 7 min. After curing treatment, aluminum-based composite current collector is obtained.

[0028] Example 3 A corrosion-resistant and highly conductive aluminum-based composite current collector comprises, from the inside out, a base film layer, aluminum substrates deposited on both sides of the base film layer, a zinc transition layer covering the surface of the aluminum substrate, and a functional surface layer formed by curing a modified coating applied to the surface of the zinc transition layer. The base film layer is a polyethylene terephthalate insulating polymer film, the aluminum substrate is formed by magnetron sputtering, the zinc transition layer is prepared by chemical deposition using a highly stable electroless zinc plating solution, and has a thickness of 300 nm. The functional surface layer is formed by curing a modified coating, and has a thickness of 5 μm.

[0029] The high-stability electroless zinc plating solution includes zinc sulfate, sodium hypophosphite, glycine, boric acid, stabilizing agent, and deionized water. The concentrations of zinc sulfate, sodium hypophosphite, glycine, boric acid, and stabilizing agent are 40 g / L, 50 g / L, 45 g / L, 20 g / L, and 3 g / L, respectively. The pH is adjusted to 10.5 with NaOH solution. The stabilizing agent consists of cocamidopropyl betaine, cerium nitrate, and thiourea in a mass ratio of 25:8:5.

[0030] The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 1.2% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 200 rpm and 70°C for 8 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 70:25:15:250. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 100 rpm for 12 hours at a temperature of 75°C. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 70°C for 12 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 80:12:20. Step S3: Place the graphene in a 150W plasma treatment instrument and treat it with argon plasma for 5 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 40 minutes. The ultrasonic power is 120W and the ultrasonic frequency is 60kHz. Dry it at 80℃ for 8 hours. The mass ratio of nickel powder, KH-550 and ethanol is 120:2:500. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 3 hours. Then add modified fluororesin and control the solid content to 35%. Under nitrogen protection, control the shear speed to 4000 rpm and shear disperse for 60 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 5:8:100.

[0031] A method for preparing an aluminum-based composite current collector with high corrosion resistance and electrical conductivity includes the following preparation steps: Step 1: The base film layer is cleaned in an ultrasonic cleaner with a power of 300W and a frequency of 60kHz for 20 minutes using a 70wt% ethanol aqueous solution. The cleaned base film layer is then placed in a plasma treatment instrument with a vacuum of 10Pa and a power of 200W. A mixture of argon and oxygen with a volume ratio of 9:1 is introduced and treated for 3 minutes. After treatment, the base film layer is vacuum dried at 80℃ for 4 hours to obtain the pretreated base film. Step 2: Deposit aluminum layers on both sides of the pretreated base film using magnetron sputtering, controlling the sputtering power to be 300W, the base film temperature to be 50℃, and the deposition rate to be 1nm / s. Deposit 5μm thick aluminum layers on both sides of the base film to form an aluminum base layer. Step 3: Immerse the aluminum substrate in a NaOH solution with pH 11 at 60℃ for 5 minutes to degrease it. After degreasing, immerse it in an H2SO4 solution with pH 4 for 30 seconds. After removal, rinse with deionized water until neutral to obtain the activated sample. Immerse the activated sample in a high-stability electroless zinc plating solution, controlling the solid-liquid mass ratio of the activated sample to the high-stability electroless zinc plating solution to be 5:12. The temperature of the high-stability electroless zinc plating solution is 80℃. Adjust the pH to 6 with H2SO4 and immerse for 120 seconds. After the reaction is complete, rinse with deionized water and dry in a 70℃ oven for 15 minutes to form a zinc transition layer. Step 4: Apply modified coating to the surface of zinc transition layer, control the coating speed to 2m / min, cure at 60℃ for 15min, raise the temperature to 100℃ and cure for 12min, and finally cure at 150℃ for 8min. After curing treatment, aluminum-based composite current collector is obtained.

[0032] Comparative Example 1 This comparative example is the same as Example 1, except that the composition of the stabilizing agent in the high-stability electroless zinc plating solution is different. The stabilizing agent is composed of cocamidopropyl betaine and cerium nitrate in a mass ratio of 10:5.

[0033] Comparative Example 2 This comparative example is the same as Example 1, except that the composition of the stabilizing agent in the high-stability electroless zinc plating solution is different. The stabilizing agent is composed of cocamidopropyl betaine and thiourea in a mass ratio of 10:3.

[0034] Comparative Example 3 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Graphene was placed in a 100W plasma treatment instrument and treated with argon plasma for 3 minutes. Nickel powder was added to a KH-550 ethanol solution and ultrasonically dispersed for 20 minutes at a power of 100W and a frequency of 40kHz. The mixture was then dried at 60℃ for 6 hours. The mass ratio of nickel powder, KH-550, and ethanol was 100:1:400. The pretreated graphene and nickel powder were mixed with N-methylpyrrolidone and ball-milled for 2 hours. Fluoropolymer was then added, and the solid content was controlled at 30%. Under nitrogen protection, the shearing speed was controlled at 3000 rpm, and the mixture was sheared and dispersed for 40 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder, and fluoropolymer was 1:5:80.

[0035] Comparative Example 4 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Step S1: Disperse vinylidene fluoride and trifluoroethyl methacrylate in N-methylpyrrolidone. Under nitrogen protection, add 0.8% of azobisisobutyronitrile (AIBN) by mass of the total monomers. React at 100 rpm and 65°C for 6 hours to obtain a modified fluoropolymer prepolymer. The mass ratio of vinylidene fluoride, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50:17:150. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 70°C for 8 hours at a stirring speed of 50 rpm. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 60°C for 10 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 50:5:10. Step S3: Place the graphene in a 100W plasma treatment instrument and treat it with argon plasma for 3 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 20 minutes. The ultrasonic power is 100W and the ultrasonic frequency is 40kHz. Dry it at 60℃ for 6 hours. The mass ratio of nickel powder, KH-550 and ethanol is 100:1:400. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 2 hours. Then add modified fluororesin and control the solid content to 30%. Under nitrogen protection, control the shear speed to 3000rpm and shear disperse for 40 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 1:5:80.

[0036] Comparative Example 5 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride and 2,3,4,5,6-pentafluorostyrene are dispersed in N-methylpyrrolidone. Under nitrogen protection, 0.8% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 100 rpm and 65°C for 6 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene and N-methylpyrrolidone is 50:17:150. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 70°C for 8 hours at a stirring speed of 50 rpm. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 60°C for 10 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 50:5:10. Step S3: Place the graphene in a 100W plasma treatment instrument and treat it with argon plasma for 3 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 20 minutes. The ultrasonic power is 100W and the ultrasonic frequency is 40kHz. Dry it at 60℃ for 6 hours. The mass ratio of nickel powder, KH-550 and ethanol is 100:1:400. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 2 hours. Then add modified fluororesin and control the solid content to 30%. Under nitrogen protection, control the shear speed to 3000rpm and shear disperse for 40 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 1:5:80.

[0037] Comparative Example 6 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 0.8% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 100 rpm and 65°C for 6 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50:12:5:150. Step S2: Add trifluorochloroethylene to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, at a temperature of 70°C, stir and react at a stirring speed of 50 rpm for 8 hours. After the reaction is completed, cool to room temperature, precipitate, filter, wash three times with deionized water, and dry at 60°C for 10 hours to obtain modified fluororesin. The mass ratio of modified fluororesin prepolymer solution to trifluorochloroethylene is 50:15. Step S3: Place the graphene in a 100W plasma treatment instrument and treat it with argon plasma for 3 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 20 minutes. The ultrasonic power is 100W and the ultrasonic frequency is 40kHz. Dry it at 60℃ for 6 hours. The mass ratio of nickel powder, KH-550 and ethanol is 100:1:400. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 2 hours. Then add modified fluororesin and control the solid content to 30%. Under nitrogen protection, control the shear speed to 3000rpm and shear disperse for 40 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 1:5:80.

[0038] Comparative Example 7 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 0.8% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 100 rpm and 65°C for 6 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50:12:5:150. Step S2: Add N-phenylmaleimide to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, at a temperature of 70°C, stir and react at a stirring speed of 50 rpm for 8 hours. After the reaction is completed, cool to room temperature, precipitate, filter, wash three times with deionized water, and dry at 60°C for 10 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution to N-phenylmaleimide is 50:15. Step S3: Place the graphene in a 100W plasma treatment instrument and treat it with argon plasma for 3 minutes. Add nickel powder to KH-550 ethanol solution and ultrasonically disperse it for 20 minutes. The ultrasonic power is 100W and the ultrasonic frequency is 40kHz. Dry it at 60℃ for 6 hours. The mass ratio of nickel powder, KH-550 and ethanol is 100:1:400. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and ball mill it for 2 hours. Then add modified fluororesin and control the solid content to 30%. Under nitrogen protection, control the shear speed to 3000rpm and shear disperse for 40 minutes to obtain the modified coating. The mass ratio of graphene, nickel powder and modified fluororesin is 1:5:80.

[0039] Comparative Example 8 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 0.8% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 100 rpm and 65°C for 6 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50:12:5:150. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 70°C for 8 hours at a stirring speed of 50 rpm. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 60°C for 10 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 50:5:10. Step S3: Add nickel powder to KH-550 ethanol solution and ultrasonically disperse for 20 min. The ultrasonic power is 100 W and the ultrasonic frequency is 40 kHz. Dry at 60℃ for 6 h. The mass ratio of nickel powder, KH-550 and ethanol is 100:1:400. Mix the pretreated nickel powder with N-methylpyrrolidone and ball mill for 2 h. Add modified fluororesin and control the solid content to 30%. Under nitrogen protection, control the shear speed to 3000 rpm and shear disperse for 40 min to obtain the modified coating. The mass ratio of nickel powder to modified fluororesin is 6:80.

[0040] Comparative Example 9 This comparative example is the same as Example 1, except that the preparation method of the modified coating is different, as detailed below: The preparation of modified coatings includes the following steps: Step S1: Vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate are dispersed in N-methylpyrrolidone. Under nitrogen protection, 0.8% of azobisisobutyronitrile (AIBN) is added. The mixture is reacted at 100 rpm and 65°C for 6 hours to obtain a modified fluororesin prepolymer solution. The mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50:12:5:150. Step S2: N-phenylmaleimide and trifluorochloroethylene are added to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, the mixture is stirred at 70°C for 8 hours at a stirring speed of 50 rpm. After the reaction is completed, the mixture is cooled to room temperature, precipitated, filtered, washed three times with deionized water, and dried at 60°C for 10 hours to obtain the modified fluororesin. The mass ratio of the modified fluororesin prepolymer solution, N-phenylmaleimide, and trifluorochloroethylene is 50:5:10. Step S3: Place the graphene in a 100W plasma treatment instrument and treat it with argon plasma for 3 minutes. Mix the pretreated graphene and nickel powder with N-methylpyrrolidone and disperse by ball milling for 2 hours. Then add modified fluororesin, control the solid content to 30%, and disperse by shearing at 3000 rpm under nitrogen protection for 40 minutes to obtain the modified coating. The mass ratio of graphene to modified fluororesin is 6:80.

[0041] Performance testing The comprehensive performance of the aluminum-based composite current collectors prepared in Examples 1-3 and Comparative Examples 1-9 of this application is as follows: Tensile strength: The tensile strength of the current collector was tested using a universal tensile testing machine in accordance with ASTM D 882-12, "Standard Test Methods for Tensile Properties of Films and Sheets". Heat resistance: Referring to the national standard GB / T 13519-2016 "Polyethylene heat shrink film for packaging", the heat resistance is measured by the heat shrinkage rate after being treated at 220℃ for 30 minutes and cooled to room temperature. Flame retardant performance test: The test was conducted in accordance with the national standard GB / T 2406.2-2009 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test". The higher the limiting oxygen index, the better the flame retardant performance. Volume swelling rate: determined according to national standard GB / T 1034-2008 "Determination of water absorption of plastics"; Sheet resistance: The sheet resistance of the current collector was determined according to the national standard GB / T 15717-2021 "Test Method for Thickness of Vacuum Metal Coating - Resistance Method". The specific test results are shown in Table 1 below.

[0042] Table 1 Performance parameters of aluminum-based composite current collectors in Examples 1-3 and Comparative Examples 1-9 As shown in Table 1, the aluminum-based composite current collector prepared in this application exhibits synergistic effects due to its multilayer structure. The zinc transition layer is dense and uniform, enhancing interfacial bonding and corrosion resistance. The modified fluororesin imparts excellent heat resistance and solvent resistance. The graphene and nickel powder composite constructs a highly efficient conductive network with low sheet resistance and good stability. It also possesses strong overall mechanical properties, high tensile strength, and good flexibility, while being lightweight, making it suitable for complex battery operating conditions and applicable to demanding electrochemical fields.

[0043] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A corrosion-resistant and highly conductive aluminum-based composite current collector, characterized in that, The aluminum-based composite current collector comprises, from the inside out, a base film layer, an aluminum substrate deposited on both sides of the base film layer, a zinc transition layer covering the surface of the aluminum substrate, and a functional surface layer formed by curing a modified coating applied to the surface of the zinc transition layer. The base film layer is a polyethylene terephthalate, polypropylene, polyimide or polyamide insulating polymer film with a thickness of 2-10 μm; The aluminum substrate is formed by magnetron sputtering or vapor deposition, and the thickness of the aluminum substrate is controlled to be 0.5-5μm; The zinc transition layer is prepared by chemical deposition using a highly stable electroless zinc plating solution, and the thickness of the zinc transition layer is controlled to be 100-300 nm. The functional surface layer is formed by curing a modified coating, and the thickness of the functional surface layer is controlled to be 1-5 μm; The preparation of the modified coating includes the following steps: Step S1: Disperse vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, and trifluoroethyl methacrylate in N-methylpyrrolidone. Under nitrogen protection, add an initiator and react at 65-70°C for 6-8 hours to obtain a modified fluororesin prepolymer. Step S2: Add N-phenylmaleimide and trifluorochloroethylene to the modified fluororesin prepolymer solution. Under continuous nitrogen protection, stir and react for 8-12 hours at a temperature of 70-75℃. After the reaction is completed, cool to room temperature, precipitate, filter, wash and dry to obtain the modified fluororesin. Step S3: After pretreatment, graphene and nickel powder are mixed with N-methylpyrrolidone, ball-milled and dispersed for 2-3 hours, then modified fluororesin is added and dispersed by high-speed shearing for 40-60 minutes to obtain the modified coating. In step S1, the mass ratio of vinylidene fluoride, 2,3,4,5,6-pentafluorostyrene, trifluoroethyl methacrylate, and N-methylpyrrolidone is 50-70:12-25:5-15:150-250. In step S2, the mass ratio of the modified fluoropolymer prepolymer, N-phenylmaleimide, and trifluorochloroethylene is 50-80:5-12:10-20. In step S3, the mass ratio of graphene, nickel powder, and modified fluororesin is 1-5:5-8:80-100.

2. The aluminum-based composite current collector with high corrosion resistance and conductivity according to claim 1, characterized in that, The high-stability electroless zinc plating solution includes zinc sulfate, sodium hypophosphite, a complexing agent, boric acid, a stabilizing agent, and deionized water. The concentrations of zinc sulfate, sodium hypophosphite, complexing agent, boric acid, and stabilizing agent are 20-40 g / L, sodium hypophosphite, complexing agent, boric acid, and stabilizing agent, respectively. The pH of the electroless zinc plating solution is adjusted to 9.0-10.5 using NaOH solution.

3. The aluminum-based composite current collector with high corrosion resistance and conductivity according to claim 2, characterized in that, The complexing agent is one or more of sodium citrate, hydroxyethylidene diphosphonic acid, and glycine.

4. The aluminum-based composite current collector with high corrosion resistance and conductivity according to claim 2, characterized in that, The stabilizing agent is composed of cocamidopropyl betaine, cerium nitrate and thiourea in a mass ratio of 10-25:5-8:3-5.

5. A method for preparing an aluminum-based composite current collector with high corrosion resistance and conductivity as described in any one of claims 1-4, characterized in that, The preparation steps include the following: Step 1: After cleaning to remove surface impurities, the base film layer is treated with plasma and then dried in a vacuum oven at 60-80℃ for 2-4 hours to obtain the pretreated base film. Step 2: Deposit aluminum layers on both sides of the pretreated base film using magnetron sputtering or vapor deposition to form an aluminum base layer; Step 3: After degreasing and acid-washing activation of the aluminum substrate surface, immerse it in a high-stability chemical zinc plating solution and react for 30-120 seconds. After the reaction is complete, rinse with deionized water and dry in an oven at 50-70℃ for 10-15 minutes to form a zinc transition layer. Step 4: Apply a modified coating to the surface of the zinc transition layer to form a functional surface layer. After curing, an aluminum-based composite current collector is obtained.

6. The method for preparing the corrosion-resistant and highly conductive aluminum-based composite current collector according to claim 5, characterized in that, The curing process in step 4 is as follows: cure at 40-60℃ for 10-15 minutes, raise the temperature to 80-100℃ and cure for 10-12 minutes, and finally cure at 120-150℃ for 5-8 minutes.

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