Aluminum-based current collector for lithium battery and preparation method of aluminum-based current collector
By coating the surface of aluminum foil with alloy slurry and combining it with ultrasonic-assisted hot-dip plating and electrophoretic deposition technology, the problems of electrolyte corrosion and interface failure of aluminum-based current collectors in lithium batteries were solved, thereby improving the cycle life and performance of the battery.
Patent Information
- Application Number
- CN202511022267.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-10-17
AI Technical Summary
Aluminum-based current collectors in lithium batteries face problems of electrolyte corrosion and interface failure during service, which seriously restricts the battery cycle life.
Aluminum foil is used as the substrate, coated with alloy slurry and then hot-dip plated, combined with ultrasonic-assisted and electrophoretic deposition technology to form a uniform coating, enhancing interface compatibility and resistance to electrolyte corrosion.
The conductivity and electrolyte corrosion resistance of the aluminum-based current collector are improved, the interface bonding strength is improved, and the cycle life of the battery is extended.
Smart Images
Figure SMS_1
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of current collectors, in particular to an aluminum-based current collector for lithium batteries and a preparation method thereof. BACKGROUND
[0002] As the most competitive electrochemical energy storage device at present, lithium batteries are widely used in electric vehicles, portable electronic devices and large-scale energy storage systems. In the structure of lithium batteries, the current collector, as one of the key components, plays an important role in collecting and transmitting current, and directly affects the charge-discharge efficiency, cycle life and safety performance of the battery. Aluminum is the preferred material for the positive electrode current collector of lithium batteries due to its unique properties, such as excellent electrical conductivity, low processing cost, lightweight, etc. Multilayer aluminum current collector is an important innovative direction to meet the demand for high energy density and high safety of lithium batteries. Through "functional layer design" (optimizing the interface of the middle layer and enhancing the corrosion resistance of the surface layer), the performance bottleneck of traditional single-layer aluminum foil is broken. However, in practical application, aluminum-based current collectors face two major challenges during service in lithium batteries: electrolyte corrosion and interface failure, which seriously restrict the cycle life of the battery. Therefore, it is urgent to find a preparation process for aluminum-based current collector materials to improve product yield while improving interface bonding, so that the aluminum-based current collector has high electrical conductivity and high electrolyte corrosion resistance. SUMMARY
[0003] The present application relates to the technical field of current collectors, in particular to an aluminum-based current collector for lithium batteries and a preparation method thereof.
[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A preparation method of an aluminum-based current collector for lithium batteries, the specific preparation steps are: S1: selecting an aluminum foil for pretreatment, including polishing-alkali washing-acid washing-activation-air drying; S2: coating alloy slurry on the surface of the pretreated aluminum foil, and then placing it in molten zinc liquid for hot dipping after pre-burning, and then taking it out and naturally solidifying; S3: polishing the zinc-plated aluminum foil after natural solidification as a cathode, and placing a stainless steel plate as an anode in an electrophoresis tank for electrophoretic deposition, and then cleaning and baking to obtain an aluminum-based current collector; Preferably, the molten zinc liquid comprises 0-0.5% Al, 0-0.08% Si, 0-0.04% Mg, 0-1.00% Sb, 0-0.30% Re and the balance of Zn in terms of chemical composition percentage; Preferably, Re is compounded with La and Ce at an element ratio of 2:3; Preferably, the specific steps in hot-dip plating are as follows: fully melting to form molten zinc liquid at 450-500℃, skimming off dross, lowering temperature to 380-400℃, and then introducing the ultrasonic head preheated to 380-400℃, placing the pre-fired aluminum foil at 30-50mm below the ultrasonic head, and applying ultrasonic power of 500-600W to form a hot-dip galvanizing layer with a total thickness of 5-10μm; Preferably, the alkali washing uses a 60-70℃ sodium hydroxide solution with a concentration of 50-60g / L, the alkali washing lasts for 2-3min; the acid washing uses a mixed acid solution, the mixed acid solution includes hydrofluoric acid with a concentration of 100-120mL / L and phosphoric acid with a concentration of 10-20mL / L, the acid washing lasts for 5-20s; the activation uses a mixed solution, the mixed solution includes ammonium hydrogen fluoride with a concentration of 40-60g / L and phosphoric acid with a concentration of 80-100mL / L, and the activation lasts for 20-30s; Preferably, the alloy slurry in S2 includes the following components in terms of mass fraction: 30-40 parts of zinc-aluminum alloy powder, 0.6-1 part of reinforcing filler, 1-1.5 parts of lanthanum nitrate, 0.3-0.5 part of nano titanium carbide, 45-50 parts of silane hydrolysis solution, 2-5 parts of Tween-20, 10-20 parts of ethylene glycol, 0.3-0.5 part of carboxymethyl cellulose, and 10-20 parts of deionized water; Preferably, the pre-firing temperature in S2 is 300-350℃, and the coating thickness after pre-firing is 50-100nm; Preferably, the preparation steps of the alloy slurry are as follows: mixing the silane coupling agent with methanol and deionized water, adjusting pH to 5, adding ethylene glycol, stirring at 35℃ for 3-5h to obtain the silane hydrolysis solution, adding the zinc-aluminum alloy powder and nano titanium carbide to continue stirring for 20-30min to obtain component A; mixing the reinforcing filler and lanthanum nitrate, adding deionized water, Tween-20, ethylene glycol, and carboxymethyl cellulose, ultrasonic dispersing for 2-3h, and then mixing with component A, continuing to stir for 1-2h, and then standing for use; Preferably, the reinforcing filler is metalized carbon nanotube and metalized graphene in a mass ratio of (0.5-2):1; wherein, the preparation steps of the metalized carbon nanotube are as follows: placing the carboxylated carbon nanotube in deionized water for ultrasonic dispersion, adding copper nitrate and stirring for 20-30min, then adding alkali liquid dropwise until pH is 10, further adding hydrazine hydrate, water-bath heating to 90℃ for 1h, cooling, centrifuging, and water washing, and then freeze-drying to obtain the metalized carbon nanotube; the preparation steps of the metalized graphene are as follows: placing the graphene oxide in deionized water for ultrasonic dispersion, adding copper nitrate and stirring for 20-30min, then adding alkali liquid dropwise until pH is 10, further adding hydrazine hydrate, water-bath heating to 90℃ for 1h, cooling, centrifuging, and water washing, and then freeze-drying to obtain the metalized graphene; Preferably, the preparation step of the electrophoretic slurry in the electrophoresis tank is: mixing zinc acetate with lye, reacting at 160 DEG C for 8h, filtering and drying, and then calcining at 450 DEG C for 3h to obtain flower-shaped zinc particles; mixing the flower-shaped zinc particles, graphene oxide, methyl methacrylate, butyl acrylate and vinyl trimethoxysilane, adding anhydrous ethanol and zinc nitrate and cerium nitrate, and ultrasonic oscillation for 2h to obtain the electrophoretic slurry; Preferably, the mass ratio of the flower-shaped zinc particles, graphene, methyl methacrylate, butyl acrylate and vinyl trimethoxysilane is (1-2):1:6:2:1. Preferably, the distance between the two electrode sheets in the electrophoretic deposition is 2cm, the deposition voltage is 120-180V, the deposition temperature is 30 DEG C, and the deposition time is 1-2min. An aluminum-based current collector for a lithium battery is prepared by the preparation method.
[0005] Compared with the prior art, the present application has the following advantages: The aluminum-based current collector prepared by the present application comprises an aluminum foil as a substrate, and a hot-dip plating is performed after the surface is coated with an alloy slurry. Considering that the thickness of the aluminum foil is relatively thin, the hot-dip plating uniformity is improved by using ultrasonic assistance under the condition of reducing the temperature of the hot-dip zinc liquid. In the alloy slurry, zinc-aluminum alloy powder, reinforcing fillers, nano titanium carbide and silane hydrolysis liquid are stirred and mixed. The reinforcing fillers are coated with copper metal by using carbon nanotubes and graphene, which improves the dispersion and improves the interfacial compatibility between the zinc-aluminum alloy powder, and at the same time, good electrical conductivity and heat dissipation effect of the aluminum foil substrate are achieved. Secondly, the alloy slurry coating reduces the deformation and other defects of the aluminum foil material caused by high temperature in the subsequent hot-dip plating, improves the plating uniformity and product yield, and forms good metallurgical bonding between the hot-dip plating layer, effectively improving the interlayer adhesion. After the hot-dip zinc plating, the flower-shaped zinc and graphene oxide coating are deposited by electrophoresis, which further reduces the corrosion rate and improves the electrolyte corrosion resistance of the aluminum foil material. Trace elements such as Mg and Al are added to the molten zinc liquid to improve the surface density of the hot-dip plating layer, reduce defects, improve the plating uniformity, and bring good protection effect. DETAILED DESCRIPTION
[0006] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0007] In the experiment, the average particle size D50 of the zinc-aluminum alloy powder is 5-7 μm, which is purchased from Zhongke Yannuo with the product number ZNAL20-2; it should be noted that the zinc-aluminum alloy powder used in the experiment needs to be treated by ball milling to obtain flaky zinc-aluminum alloy powder with an average thickness of 30 nm; The nano-titanium carbide has a particle size of 20 nm and is purchased from Gelite; The preparation steps of the metalized carbon nanotube are as follows: 0.5 g of carboxylated carbon nanotube is ultrasonically dispersed in 500 mL of deionized water, 100 mL of copper nitrate with a concentration of 0.05 g / mL is added and stirred for 30 min, then alkali is added dropwise until the pH is 10, 50 mL of hydrazine hydrate is added, the water bath is warmed to 90°C and reacted for 1 h, then cooled, centrifuged, washed with water, and freeze-dried to obtain the metalized carbon nanotube; the carboxylated carbon nanotube is purchased from Xianfeng Nano with the product number 102704; The preparation steps of the metalized graphene are as follows: 0.5 g of graphene oxide is ultrasonically dispersed in 500 mL of deionized water, 100 mL of copper nitrate with a concentration of 0.05 g / mL is added and stirred for 30 min, then alkali is added dropwise until the pH is 10, 50 mL of hydrazine hydrate is added, the water bath is warmed to 90°C and reacted for 1 h, then cooled, centrifuged, washed with water, and freeze-dried to obtain the metalized graphene; the graphene oxide is purchased from Xianfeng Nano with the product number 100602; The molten zinc liquid includes, in terms of percentage by chemical composition: 0.2% Al, 0.08% Si, 0.04% Mg, 0.50% Sb, 0.30% Re, and the balance Zn; wherein Re is a complex of La and Ce with an element ratio of 2:3; The positive active paste includes, in terms of percentage by mass: 97% NCM, 1% SP, and 2% PVDF; the NCM is purchased from Defang Nano with the model S90F; the SP is purchased from Cabot with the model Li-300; and the PVDF is purchased from Funolin with the model FL2032; The negative active paste includes, in terms of percentage by mass: 95% graphite, 2% SP, 1.5% CMC, and 1.5% SBR; the graphite is wield Betrui BFC series; the CMC is purchased from Shandong Weifang Litai Composite Material with the model FH6-A; and the SBR is purchased from Langsheng with the model MP62; Embodiment 1: The embodiment provides a preparation method of an aluminum-based current collector for a lithium battery, and the specific steps are as follows: S1: Select an aluminum foil with a thickness of 10 μm for pretreatment, polish it, then alkali wash it with a 50 g / L sodium hydroxide solution at 70°C for 2 min, then acid wash it in a mixed acid solution with a concentration of 100 mL / L hydrofluoric acid and 10 mL / L phosphoric acid for 15 s, and finally activate it in a mixed solution with a concentration of 40 g / L ammonium hydrogen fluoride and 100 mL / L phosphoric acid for 20 s; S2: mixing KH560, methanol and deionized water according to the mass ratio of 1:1:3, adjusting pH to 5, then adding 2% of ethylene glycol based on the mass of the above mixed solution, stirring at 35℃ for 3h to obtain a silane hydrolysis solution; taking 48 parts of the silane hydrolysis solution, adding 36 parts of zinc-aluminum alloy powder and 0.5 parts of nano titanium carbide, and continuing to stir for 30 min to obtain component A; mixing 1 part of reinforcing filler and 1 part of lanthanum nitrate, adding 10 parts of deionized water, 3 parts of Tween-20, 10 parts of ethylene glycol and 0.5 parts of carboxymethyl cellulose, ultrasonic dispersion for 2h, then mixing with component A, continuing to stir for 1h and standing to obtain alloy slurry; wherein the mass ratio of metalized carbon nanotube and metalized graphene in the reinforcing filler is 0.5:1; S3: coating the alloy slurry on the surface of the pretreated aluminum foil, pre-burning at 300℃ to obtain a coating thickness of 100nm; fully melting at 450℃ to form a molten zinc liquid, skimming off the dross, cooling to 380℃, then introducing into a preheated ultrasonic head at 380℃, placing the pre-burned aluminum foil 30mm below the ultrasonic head, applying ultrasonic power of 500W, taking out after completion, and naturally solidifying to form a hot-dip galvanized layer with a total thickness of 10μm; S4: polishing the naturally solidified galvanized aluminum foil as a cathode, and placing a stainless steel plate as an anode in an electrophoresis tank for electrophoretic deposition, the distance between the cathode and anode is 2cm, the deposition voltage is 120V, the deposition temperature is 30℃, and the deposition is completed after 2min, then washing and baking at 160℃ for 20min to obtain an aluminum-based current collector; The preparation steps of the electrophoretic slurry in the electrophoresis tank are as follows: mixing 500mL of zinc acetate solution with a concentration of 0.2mol / L and 500mL of sodium hydroxide solution with a concentration of 2.0mol / L, then reacting at 160℃ for 8h, filtering and drying, then calcining at 450℃ for 3h to obtain flower-like zinc particles; mixing 5g of flower-like zinc particles, 5g of graphene oxide, 30g of methyl methacrylate, 10g of butyl acrylate and 5g of vinyl trimethoxysilane, adding 200g of anhydrous ethanol and 1g of zinc nitrate and 0.5g of cerium nitrate, and ultrasonic oscillation for 2h to obtain an electrophoretic slurry.
[0008] Example 2: The present embodiment provides a preparation method of an aluminum-based current collector for lithium battery, and the specific steps are as follows: S1: selecting an aluminum foil with a thickness of 10μm for pretreatment, polishing, then alkali washing with 70℃ sodium hydroxide solution with a concentration of 50g / L for 2min, then acid washing in a mixed acid solution of hydrogen fluoride acid with a concentration of 100mL / L and phosphoric acid with a concentration of 10mL / L for 15s, and finally activating in a mixed solution of ammonium hydrogen fluoride with a concentration of 50g / L and phosphoric acid with a concentration of 100mL / L for 20s; S2: mixing KH560, methanol and deionized water according to the mass ratio of 1:1:3, adjusting pH to 5, then adding 2% of ethylene glycol based on the mass of the above mixed solution, stirring at 35℃ for 3h to obtain a silane hydrolysis solution; taking 48 parts of the silane hydrolysis solution, adding 36 parts of zinc-aluminum alloy powder and 0.5 parts of nano titanium carbide, and continuing to stir for 30 min to obtain component A; mixing 1 part of reinforcing filler and 1 part of lanthanum nitrate, adding 10 parts of deionized water, 3 parts of Tween-20, 10 parts of ethylene glycol and 0.5 parts of carboxymethyl cellulose, ultrasonic dispersion for 3h, then mixing with component A, continuing to stir for 2h and standing to obtain an alloy slurry; wherein the mass ratio of metalized carbon nanotube and metalized graphene in the reinforcing filler is 1:1; S3: coating the alloy slurry on the surface of the pretreated aluminum foil, pre-baking at 320℃ to obtain a coating layer with a thickness of 100nm, fully melting at 480℃ to form a molten zinc liquid, skimming off the dross, reducing the temperature to 380℃, then introducing the ultrasonic head preheated to 380℃, placing the pre-baked aluminum foil 40mm below the ultrasonic head, applying ultrasonic power of 600W, forming a hot-dip galvanized layer with a total thickness of 10μm, and then taking out for natural solidification; S4: polishing the naturally solidified galvanized aluminum foil as a cathode, and placing a stainless steel plate as an anode in an electrophoresis tank for electrophoretic deposition, the distance between the cathode and the anode is 2cm, the deposition voltage is 160V, the deposition temperature is 30℃, and the deposition is completed after 2min of deposition, then washing and baking at 160℃ for 20min to obtain an aluminum-based current collector; The preparation steps of the electrophoretic slurry in the electrophoresis tank are as follows: mixing 500mL of zinc acetate solution with a concentration of 0.2mol / L with 500mL of sodium hydroxide solution with a concentration of 2.0mol / L, then reacting at 160℃ for 8h, filtering and drying, then calcining at 450℃ for 3h to obtain flower-like zinc particles; mixing 6g of flower-like zinc particles, 5g of graphene oxide, 30g of methyl methacrylate, 10g of butyl acrylate and 5g of vinyl trimethoxysilane, adding 200g of anhydrous ethanol and 1g of zinc nitrate and 0.5g of cerium nitrate, and ultrasonic oscillation for 2h to obtain an electrophoretic slurry.
[0009] Example 3: The present embodiment provides a preparation method of an aluminum-based current collector for lithium battery, and the specific steps are as follows: S1: selecting an aluminum foil with a thickness of 10μm for pretreatment, polishing, then alkali washing with 70℃ sodium hydroxide solution with a concentration of 50g / L for 2min, then acid washing in a mixed acid solution of 100mL / L hydrofluoric acid and 10mL / L phosphoric acid for 15s, and finally activating in a mixed solution of 50g / L ammonium hydrogen fluoride and 100mL / L phosphoric acid for 20s; S2: mixing KH560, methanol and deionized water according to the mass ratio of 1:1:3, adjusting pH to 5, then adding 2% of the above mixed solution by mass of ethylene glycol, stirring at 35℃ for 3h to obtain silane hydrolysis solution, taking 48 parts of silane hydrolysis solution, adding 36 parts of zinc-aluminum alloy powder and 0.5 parts of nano titanium carbide, and continuing to stir for 30 min to obtain component A; mixing 1 part of reinforcing filler and 1 part of lanthanum nitrate, adding 10 parts of deionized water, 3 parts of Tween-20, 10 parts of ethylene glycol and 0.5 parts of carboxymethyl cellulose, ultrasonic dispersion for 2-3h, then mixing with component A, continuing to stir for 1-2h and standing to obtain alloy slurry; wherein the mass ratio of metalized carbon nanotube and metalized graphene in the reinforcing filler is 1:1; S3: coating the alloy slurry on the surface of the pretreated aluminum foil, pre-baking at 350℃ to obtain a coating thickness of 100nm, fully melting at 500℃ to form molten zinc liquid, skimming off the dross, cooling to 390℃, then introducing the preheated ultrasonic head to 390℃, placing the pre-baked aluminum foil 50mm below the ultrasonic head, applying ultrasonic power of 600W to form a hot-dip galvanized layer with a total thickness of 10μm, then taking out and naturally solidifying; S4: polishing the naturally solidified galvanized aluminum foil as a cathode, and placing a stainless steel plate as an anode in an electrophoresis tank for electrophoretic deposition, the distance between the cathode and the anode is 2cm, the deposition voltage is 180V, the deposition temperature is 30℃, and the deposition is completed after 2min of deposition, then washing and baking at 160℃ for 20min to obtain an aluminum-based current collector; The preparation steps of the electrophoretic slurry in the electrophoresis tank are as follows: mixing 500mL of zinc acetate solution with a concentration of 0.2mol / L with 500mL of sodium hydroxide solution with a concentration of 2.0mol / L, then reacting at 160℃ for 8h, filtering and drying, then calcining at 450℃ for 3h to obtain flower-like zinc particles; mixing 6g of flower-like zinc particles, 5g of graphene oxide, 30g of methyl methacrylate, 10g of butyl acrylate and 5g of vinyl trimethoxysilane, adding 200g of anhydrous ethanol and 1g of zinc nitrate and 0.5g of cerium nitrate, and ultrasonic oscillation for 2h to obtain an electrophoretic slurry.
[0010] Comparative Example 1: as a control experiment of Example 2, no alloy slurry coating was performed, and the specific steps are as follows: S1: selecting an aluminum foil with a thickness of 10μm for pretreatment, polishing, then alkali washing with 70℃ sodium hydroxide solution with a concentration of 50g / L for 2min, then acid washing in a mixed acid solution of 100mL / L hydrofluoric acid and 10mL / L phosphoric acid for 15s, and finally activating in a mixed solution of 50g / L ammonium hydrogen fluoride and 100mL / L phosphoric acid for 20s; S2: After the pretreatment of the aluminum foil, pre-burning at 320℃; fully melting at 480℃ to form molten zinc liquid, skimming off the dross, and then lowering the temperature to 380℃ and introducing the preheated ultrasonic head to 380℃, placing the pre-burned aluminum foil 40mm below the ultrasonic head to apply vibration, with an ultrasonic power of 600W, forming a hot-dip galvanized layer with a total thickness of 10μm, and then taking it out for natural solidification after completion; S3: After the natural solidification of the galvanized aluminum foil, polishing it as a cathode, and placing a stainless steel plate as an anode in an electrophoresis tank for electrophoretic deposition, with a distance between the cathode and anode of 2cm, a deposition voltage of 160V, a deposition temperature of 30℃, and a deposition time of 2min, then cleaning and baking at 160℃ for 20min to obtain an aluminum-based current collector; The preparation steps of the electrophoresis slurry in the electrophoresis tank are as follows: mixing 500mL of a zinc acetate solution with a concentration of 0.2mol / L and 500mL of a sodium hydroxide solution with a concentration of 2.0mol / L, then reacting at 160℃ for 8h, filtering and drying, and then calcining at 450℃ for 3h to obtain flower-shaped zinc particles; mixing 6g of flower-shaped zinc particles, 5g of graphene oxide, 30g of methyl methacrylate, 10g of butyl acrylate, and 5g of vinyl trimethoxysilane, adding 200g of anhydrous ethanol and 1g of zinc nitrate and 0.5g of cerium nitrate, and ultrasonic oscillation for 2h to obtain an electrophoresis slurry.
[0011] Comparative Example 2: As a control experiment of Example 2, no electrophoretic deposition was performed, and the specific steps are as follows: S1: Selecting an aluminum foil with a thickness of 10μm for pretreatment, polishing it, and then alkali washing it with a 70℃ sodium hydroxide solution with a concentration of 50g / L for 2min, then acid washing it in a mixed acid solution of hydrofluoric acid with a concentration of 100mL / L and phosphoric acid with a concentration of 10mL / L for 15s, and finally activating it in a mixed solution of ammonium hydrogen fluoride with a concentration of 50g / L and phosphoric acid with a concentration of 100mL / L for 20s; S2: Mixing KH560, methanol, and deionized water in a mass ratio of 1:1:3, adjusting the pH to 5, and then adding 2% ethylene glycol based on the mass of the above mixed solution, and stirring at 35℃ for 3h to obtain a silane hydrolysis solution, taking 48 parts of the silane hydrolysis solution, adding 36 parts of zinc-aluminum alloy powder and 0.5 parts of nano titanium carbide, and continuing to stir for 30min to obtain component A; mixing 1 part of reinforcing filler and 1 part of lanthanum nitrate, adding 10 parts of deionized water, 3 parts of Tween-20, 10 parts of ethylene glycol, and 0.5 parts of carboxymethyl cellulose, ultrasonic dispersion for 3h, and then mixing with component A, continuing to stir for 2h, and then standing for use, obtaining an alloy slurry; the mass ratio of metalized carbon nanotubes and metalized graphene in the reinforcing filler is 1:1; S3: coating the alloy slurry on the pretreated aluminum foil surface, pre-burning at 320℃ to obtain a coating thickness of 100 nm, fully melting at 480℃ to form a molten zinc liquid, skimming off the dross, and then introducing the preheated ultrasonic head at 380℃ after cooling to 380℃, placing the pre-burned aluminum foil 40 mm below the ultrasonic head to form a hot-dip galvanized layer with a total thickness of 10 μm, and then taking it out for natural solidification; S4: polishing the galvanized aluminum foil after natural solidification to obtain an aluminum-based current collector; Test experiment The aluminum-based current collectors prepared in Examples 1-3 and Comparative Examples 1-2 were coated with positive active slurry on the surface as positive electrode sheets, coated with negative active slurry on the surface of copper foil as negative electrode sheets, PP separator, and electrolyte (containing 1 mol / L LiPF6 in carbonate solution, solvent being propylene carbonate, ethylene carbonate, and methyl ethyl carbonate at a mass ratio of 1:1:1) to assemble lithium batteries. The batteries were cycled at 45℃ with a 1C charge-discharge rate in a voltage range of 3.0V-4.2V for 100 times, and the capacity retention rate of the cycled batteries was recorded. After disassembling, washing off the positive active slurry on the surface of the aluminum-based current collector, and observing the surface corrosion, the surface was considered to be qualified if it was flat, spotless, and colorless, and unqualified if it was partially damaged with cracks or peeling, had serious corrosion spots, and was severely discolored. The results are shown in Table 1. Table 1
[0012] Conclusion: From the data obtained from the above experiments, it can be seen that Example 2 achieved a better battery cycle capacity retention rate, while Comparative Example 1, as a control experiment of Example 2, did not coat the intermediate alloy slurry, which had an impact on the aluminum-based current collector itself, but the battery cycle capacity retention rate decreased more obviously. Comparative Example 2 did not perform electrophoretic deposition, and the corrosion degree of the electrolyte on the aluminum-based current collector increased.
[0013] It is apparent for those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the present application should be defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the claims.
Claims
1. A method for preparing an aluminum-based current collector for a lithium battery, characterized in that: The specific preparation steps are: S1: Select an aluminum foil for pretreatment, including grinding - alkali washing - acid washing - activation - air drying; S2: Coating the alloy slurry on the surface of the pretreated aluminum foil, pre-calcining it, placing it in molten zinc solution for hot dip plating, and then taking it out to solidify naturally after completion; S3: After naturally solidified, the galvanized aluminum foil is polished and used as the cathode, and the stainless steel plate is used as the anode and placed in the electrophoretic tank for electrophoretic deposition. After completion, the aluminum-based current collector is obtained by cleaning and baking.
2. The method for preparing an aluminum-based current collector for a lithium battery according to claim 1, wherein: The molten zinc solution comprises, in terms of chemical composition percentages, 0-0.5% Al, 0-0.08% Si, 0-0.04% Mg, 0-1.00% Sb, 0-0.30% Re, and the balance Zn; wherein Re is compounded with La and Ce in an element ratio of 2:
3.
3. The method for preparing an aluminum-based current collector for a lithium battery according to claim 1, wherein: The specific steps of hot-dip galvanizing are: fully melt at 450~500℃ to form molten zinc liquid, skim off the slag, cool to 380~400℃ and then introduce it into an ultrasonic head preheated to 380~400℃, place the pre-burned aluminum foil 30~50mm below the ultrasonic head and vibrate it with an ultrasonic power of 500~600W to form a hot-dip galvanized layer with a total thickness of 5~10μm.
4. The method for preparing an aluminum-based current collector for a lithium battery according to claim 1, wherein: The alkaline washing adopts a sodium hydroxide solution with a concentration of 50-60 g / L at 60-70° C. for 2-3 minutes; the acid washing adopts a mixed acid solution including a hydrofluoric acid with a concentration of 100-120 mL / L and a phosphoric acid with a concentration of 10-20 mL / L for 5-20 seconds; The activation was performed using a mixed solution comprising 40-60 g / L ammonium bifluoride and 80-100 mL / L phosphoric acid for 20-30 seconds.
5. The method for preparing an aluminum-based current collector for a lithium battery according to claim 1, wherein: The alloy slurry in S2 includes the following components in parts by mass: 30-40 parts of zinc-aluminum alloy powder, 0.6-1 parts of reinforcing filler, 1-1.5 parts of lanthanum nitrate, 0.3-0.5 parts of nano-titanium carbide, 45-50 parts of silane hydrolyzate, 2-5 parts of Tween-20, 10-20 parts of ethylene glycol, 0.3-0.5 parts of carboxymethyl cellulose, and 10-20 parts of deionized water; the pre-firing temperature in S2 is 300-350°C, and the coating thickness after pre-firing is 50-100 nm.
6. The method for preparing an aluminum-based current collector for a lithium battery according to claim 5, characterized in that: The alloy slurry is prepared by mixing a silane coupling agent with methanol and deionized water, adjusting the pH to 5, adding ethylene glycol, stirring at 35° C. for 3 to 5 hours to obtain a silane hydrolyzate, adding zinc-aluminum alloy powder and nano-titanium carbide, and continuing to stir for 20 to 30 minutes to obtain component A; mixing a reinforcing filler and lanthanum nitrate, adding deionized water, Tween-20, ethylene glycol, and carboxymethyl cellulose, ultrasonically dispersing for 2 to 3 hours, mixing with component A, continuing to stir for 1 to 2 hours, and then standing for use.
7. The method for preparing an aluminum-based current collector for a lithium battery according to claim 5, characterized in that: The reinforcing filler comprises metallized carbon nanotubes and metallized graphene in a mass ratio of (0.5-2):1; the preparation steps of the metallized carbon nanotubes are as follows: placing carboxylated carbon nanotubes in deionized water for ultrasonic dispersion, adding copper nitrate, stirring for 20-30 minutes, then adding alkaline solution dropwise until the pH value is 10, then adding hydrazine hydrate, heating the water bath to 90°C for reaction for 1 hour, then cooling, centrifuging, washing with water, and freeze-drying to obtain the metallized carbon nanotubes; the preparation steps of the metallized graphene are as follows: placing graphene oxide in deionized water for ultrasonic dispersion, adding copper nitrate, stirring for 20-30 minutes, then adding alkaline solution dropwise until the pH value is 10, then adding hydrazine hydrate, heating the water bath to 90°C for reaction for 1 hour, then cooling, centrifuging, washing with water, and freeze-drying to obtain the metallized graphene.
8. The method for preparing an aluminum-based current collector for a lithium battery according to claim 1, wherein: The electrophoretic slurry in the electrophoretic tank is prepared by mixing zinc acetate with an alkali solution, reacting at 160° C. for 8 hours, filtering and drying, and calcining at 450° C. for 3 hours to obtain flower-shaped zinc particles; mixing the flower-shaped zinc particles, graphene oxide, methyl methacrylate, butyl acrylate, and vinyltrimethoxysilane, adding anhydrous ethanol, zinc nitrate, and cerium nitrate, and ultrasonically oscillating for 2 hours to obtain the electrophoretic slurry; the mass ratio of the flower-shaped zinc particles to graphene, methyl methacrylate, butyl acrylate, and vinyltrimethoxysilane is (1-2): 1:6:2:
1.
9. The method for preparing an aluminum-based current collector for a lithium battery according to claim 1, wherein: During electrophoretic deposition, the distance between the two electrodes is 2 cm, the deposition voltage is 120-180 V, the deposition temperature is 30°C, and the deposition time is 1-2 min.
10. An aluminum-based current collector for a lithium battery, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 9.