Preparation method of high-rate carbon-coated aluminum foil current collector for lithium battery

Abstract

The present application relates to the technical field of carbon-coated current collector, in particular to a preparation method of high-rate carbon-coated aluminum foil current collector for lithium battery, the present application improves the cohesion of the slurry and the contact with the surface of the aluminum foil through the modification of the binder, thereby effectively coping with the volume change caused by the deintercalation and intercalation of lithium ions at high rate, ensuring the stability of the electrode material during high-rate charge and discharge process. The present application also uses lithium methacrylate and butyl acrylate as monomers to prepare a polyacrylate binder, and adds hexamethylene diisocyanate to enhance the compatibility between the binder and the graphene loaded with carbon powder, so that the graphene loaded with carbon powder is more uniformly dispersed in the polyacrylate binder, the peeling strength of the carbon-coated aluminum foil current collector is enhanced, the capacity retention is improved, and the performance of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of carbon-coated current collector technology, specifically a method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries. Background Technology

[0002] Lithium-ion batteries are widely used in many fields such as automobiles and mobile phones due to their high energy density. The main components of a lithium battery include positive and negative electrode active materials, electrolyte, separator, and positive and negative electrode current collectors. Currently, aluminum foil, copper foil, composite aluminum foil, composite copper foil, and carbon-coated aluminum foil, carbon-coated copper foil, composite carbon-coated aluminum foil, and composite carbon-coated copper foil with improved surfaces are the main materials used to transport electrons. However, traditional aluminum foil or copper foil current collectors have the problem of high interfacial resistance, while carbon-coated current collectors can improve interfacial resistance and improve the charging and discharging of the battery. Existing carbon coating layers can effectively improve the capacity retention rate under normal charging and discharging conditions, but there is still significant capacity decay during high-rate charging and discharging. The carbon-coated current collector of this invention can improve the capacity retention rate of the battery under high-rate charging and discharging. By increasing the cohesion of the electrode material and improving the affinity with the aluminum foil surface, the capacity retention rate is guaranteed under high current.

[0003] To address the aforementioned issues and improve the capacity retention rate of current collectors under high current conditions, this invention provides a method for preparing high-rate carbon-coated aluminum foil current collectors for lithium batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries includes the following steps:

[0007] Step 1: Take the adhesive, deionized water, and modifier, and stir them evenly to obtain the modified adhesive;

[0008] Step 2: Mix the modified binder, conductive powder, deionized water, and crosslinking agent evenly to obtain a slurry;

[0009] Step 3: Coat the slurry onto the surface of the current collector for lithium batteries and bake to obtain a carbon-coated aluminum foil current collector;

[0010] The slurry comprises the following components, by mass percentage: 10-60% binder, 0.1-2% modifier, 10-30% deionized water, 10-30% conductive powder, and 0.1%-2% crosslinking agent.

[0011] In a more optimized manner, in step one, the adhesive is modified. During the modification process, the adhesive and the modifier are stirred, and deionized water is added at the same time. The stirring speed is 10-40 rpm and the stirring time is 10-30 min.

[0012] Ideally, in step three, the baking temperature is 70-130℃ and the baking time is 20s-3min.

[0013] More preferably, the modifier is any one of dibutyl ester, KH-550, and KH-507.

[0014] More preferably, the crosslinking agent is any one or more of zinc acetate, magnesium acetate, calcium acetate, aziridine, alkoxysilane, and calcium hydroxide.

[0015] More preferably, the adhesive is any one or more of polytetrafluoroethylene emulsion, styrene-butadiene emulsion, polyacrylate adhesive, and polyvinyl acetate adhesive.

[0016] A more optimized method for preparing the polyacrylate adhesive is as follows: take lithium methacrylate and deionized water, stir evenly, add butyl acrylate and hexamethylene diisocyanate, react with nitrogen gas for 30-40 min, add ammonium persulfate, heat to 70-80℃, add butyl acrylate and divinylbenzene, react for 11-13 h to obtain the polyacrylate adhesive.

[0017] Ideally, the conductive powder is any one or more of acetylene black, graphene, and carbon powder.

[0018] More preferably, the conductive powder is graphene loaded with carbon powder, and the preparation method of the graphene loaded with carbon powder includes the following steps:

[0019] S1: Take graphene and acetone, disperse them by ultrasonication, add 1-aminopyrene, stir for 30-40 min, add propyltriethylisocyanate coupling agent, react for 7-9 h, centrifuge, wash and dry to obtain modified graphene.

[0020] S2: Take modified graphene, modified carbon powder, and deionized water, stir evenly, add ammonia water, continue stirring for 50-70 minutes, centrifuge, wash, and dry to obtain graphene loaded with carbon powder.

[0021] In a more optimized manner, the modified toner in S2 is prepared as follows: take tung oil acid and toluene, stir evenly to obtain a mixed solution; take toner and toluene, disperse ultrasonically, add to the mixed solution, heat to 95-100℃, react for 4-5 hours, filter, wash and dry to obtain modified toner.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0023] (1) In this paper, graphene loaded with carbon powder was added to the binder, which increased the specific surface area of ​​graphene, thereby increasing the contact area between the binder and the copper foil and enhancing the interaction between the binder and the current collector. At the same time, the loading of carbon powder can enhance the dispersibility of graphene in the binder and enhance the peel strength of the carbon-coated aluminum foil current collector.

[0024] This invention uses tung oil acid to modify toner. The carboxyl groups on tung oil acid can react with the hydroxyl groups on toner. Furthermore, the unsaturated double bonds on tung oil acid can promote cross-linking, improve the dispersibility of graphene loaded with toner in the binder, strengthen the interaction force, and enhance the peel strength of the carbon-coated aluminum foil current collector.

[0025] This invention uses 1-aminopyrene to modify graphene, and then grafts propyltriethoxysilane isocyanate onto the graphene surface. Through coupling, carbon powder is loaded onto the graphene, and at the same time, the graphene loaded with carbon powder has isocyanate groups.

[0026] Secondly, this invention uses lithium methacrylate and butyl acrylate as monomers to prepare a polyacrylate binder, and adds hexamethylene diisocyanate. The hexamethylene diisocyanate has isocyanate groups, which enhances the compatibility between the binder and the graphene loaded with carbon powder, so that the graphene loaded with carbon powder is evenly dispersed in the polyacrylate binder, which enhances the peel strength of the carbon-coated aluminum foil current collector, improves the capacity retention rate, and thus improves the performance of the battery.

[0027] (2) By modifying the binder, the present invention improves the cohesiveness of the slurry and its contact with the aluminum foil surface, thereby effectively coping with the volume changes caused by lithium ion deintercalation and intercalation at high rates, ensuring the stability of the electrode material during high-rate charging and discharging, and thus improving the performance of the battery. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] There are no special restrictions on the suppliers of any of the raw materials involved in this invention. Exemplary examples include: polyacrylate binder: model SA-227, which can be purchased from Anhui Zhongen Chemical; silane coupling agent KH-507: which can be purchased from Shin-Etsu Chemical Co., Ltd., Japan; graphene powder: which can be purchased from Kramar Reagent, with a particle size of 5-10 μm; carbon powder: which can be purchased from Brofos, with a particle size of 500 nm, item number: Brofos-C-500; aluminum sheet: item number lp123tt, which can be purchased from Flextronics Insulation Materials; tung oil acid: model T160, which can be purchased from Shanghai Gaoming Chemical Co., Ltd.; propyltriethoxysilane isocyanate coupling agent: which can be purchased from Aladdin; butyl acrylate: which can be purchased from Maclean's; lithium methacrylate: which can be purchased from Shanghai Yuanye; hexamethylene diisocyanate: which can be purchased from Maclean's.

[0030] Example 1: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0031] Step 1: Preparation of polyacrylate adhesive:

[0032] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 45℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 35min, add 0.5g of ammonium persulfate, heat to 75℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 12h to obtain polyacrylate adhesive;

[0033] Step 2: Preparation of carbon-coated aluminum foil current collector:

[0034] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 40 rpm for 15 min to obtain a modified binder. Mix the modified binder with 1 kg of carbon powder, 1 kg of graphene powder, 2 kg of deionized water, and 0.02 kg of aziridine and stir for 2.5 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100℃ for 1.5 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0035] Example 2: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0036] Step 1: Preparation of polyacrylate adhesive:

[0037] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 45℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 30min, add 0.5g of ammonium persulfate, heat to 70℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 11h to obtain polyacrylate adhesive;

[0038] Step 2: Preparation of carbon-coated aluminum foil current collector:

[0039] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.2 kg of KH-507 and stir at 40 rpm for 10 min to obtain a modified binder. Mix the modified binder with 1 kg of carbon powder, 1 kg of graphene powder, 2 kg of deionized water, and 0.02 kg of aziridine and stir for 2 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100℃ for 1 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0040] Example 3: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0041] Step 1: Preparation of polyacrylate adhesive:

[0042] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 55℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 40min, add 0.5g of ammonium persulfate, heat to 80℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 13h to obtain polyacrylate adhesive;

[0043] Step 2: Preparation of carbon-coated aluminum foil current collector:

[0044] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 50 rpm for 20 min to obtain a modified binder. Mix the modified binder with 1 kg of carbon powder, 1 kg of graphene powder, 2 kg of deionized water, and 0.015 kg of aziridine and stir for 3 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100℃ for 2 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0045] Example 4: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0046] Step 1: Preparation of polyacrylate adhesive:

[0047] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 55℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 40min, add 0.5g of ammonium persulfate, heat to 80℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 13h to obtain polyacrylate adhesive;

[0048] Step 2: Preparation of carbon-coated aluminum foil current collector:

[0049] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 50 rpm for 20 min to obtain a modified binder. Mix the modified binder with 1 kg of carbon powder, 1 kg of graphene powder, 2 kg of deionized water, and 0.01 kg of aziridine and stir for 3 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100℃ for 2 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0050] Example 5: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0051] Step 1: Preparation of modified toner:

[0052] Take 1.5g of tung oil acid and 30mL of toluene, stir well to obtain a mixed solution; take 2g of carbon powder and 50mL of toluene, ultrasonically disperse for 1h, add to the mixed solution, heat to 97℃, react for 4.5h, filter, wash and dry to obtain modified carbon powder;

[0053] Step 2: Preparation of graphene loaded with carbon powder:

[0054] Take 3g of graphene and 50mL of acetone, sonicate for 2.5h, add 0.2g of 1-aminopyrene, stir for 35min, add 0.2g of propyltriethoxysilane isocyanate, react for 8h, centrifuge, wash and dry to obtain modified graphene;

[0055] Take 1g of modified graphene, 1g of modified carbon powder, and 50mL of deionized water, stir well, add 5wt% ammonia water, adjust the pH value to 8, continue stirring for 60min, centrifuge, wash, and dry to obtain graphene loaded with carbon powder.

[0056] Step 3: Preparation of polyacrylate adhesive:

[0057] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 50℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 35min, add 0.5g of ammonium persulfate, heat to 75℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 12h to obtain polyacrylate adhesive;

[0058] Step 4: Preparation of carbon-coated aluminum foil current collector:

[0059] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 50 rpm for 15 min to obtain a modified binder. Mix the modified binder with 2 kg of graphene loaded with carbon powder, 2 kg of deionized water, and 0.02 kg of aziridine and stir for 2.5 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100 °C for 1 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0060] Example 6: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0061] Step 1: Preparation of modified toner:

[0062] Take 1.5g of tung oil acid and 30mL of toluene, stir well to obtain a mixed solution; take 2g of carbon powder and 50mL of toluene, ultrasonically disperse for 1h, add to the mixed solution, heat to 95℃, react for 4h, filter, wash and dry to obtain modified carbon powder;

[0063] Step 2: Preparation of graphene loaded with carbon powder:

[0064] Take 3g of graphene and 50mL of acetone, sonicate for 2h, add 0.2g of 1-aminopyrene, stir for 30min, add 0.2g of propyltriethoxysilane isocyanate, react for 7h, centrifuge, wash and dry to obtain modified graphene;

[0065] Take 1g of modified graphene, 1g of modified carbon powder, and 50mL of deionized water, stir evenly, add 5wt% ammonia water, adjust the pH value to 8, continue stirring for 50min, centrifuge, wash, and dry to obtain graphene loaded with carbon powder.

[0066] Step 3: Preparation of polyacrylate adhesive:

[0067] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 45℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 30min, add 0.5g of ammonium persulfate, heat to 70℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 11h to obtain polyacrylate adhesive;

[0068] Step 4: Preparation of carbon-coated aluminum foil current collector:

[0069] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 40 rpm for 10 min to obtain a modified binder. Mix the modified binder with 2 kg of graphene loaded with carbon powder, 2 kg of deionized water, and 0.02 kg of aziridine and stir for 2 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100℃ for 1 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0070] Example 7: A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, comprising the following steps:

[0071] Step 1: Preparation of modified toner:

[0072] Take 1.5g of tung oil acid and 30mL of toluene, stir well to obtain a mixed solution; take 2g of carbon powder and 50mL of toluene, ultrasonically disperse for 1h, add to the mixed solution, heat to 100℃, react for 5h, filter, wash and dry to obtain modified carbon powder;

[0073] Step 2: Preparation of graphene loaded with carbon powder:

[0074] Take 3g of graphene and 50mL of acetone, sonicate for 3h, add 0.2g of 1-aminopyrene, stir for 40min, add 0.2g of propyltriethoxysilane isocyanate, react for 9h, centrifuge, wash and dry to obtain modified graphene;

[0075] Take 1g of modified graphene, 1g of modified carbon powder, and 50mL of deionized water, stir evenly, add 5wt% ammonia water, adjust the pH value to 8, continue stirring for 70min, centrifuge, wash, and dry to obtain graphene loaded with carbon powder.

[0076] Step 3: Preparation of polyacrylate adhesive:

[0077] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 55℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 40min, add 0.5g of ammonium persulfate, heat to 80℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 13h to obtain polyacrylate adhesive;

[0078] Step 4: Preparation of carbon-coated aluminum foil current collector:

[0079] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 50 rpm for 20 min to obtain a modified binder. Mix the modified binder with 2 kg of graphene loaded with carbon powder, 2 kg of deionized water, and 0.02 kg of aziridine and stir for 3 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100℃ for 2 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0080] Comparative Example 1: A polyacrylate adhesive of type SA-227 was used, and the rest was the same as in Example 1;

[0081] Take 8 kg of polyacrylate adhesive and 2 kg of deionized water, and stir at 50 rpm for 20 min to obtain a mixed adhesive; mix the mixed adhesive with 1 kg of carbon powder, 1 kg of graphene powder and 2 kg of deionized water for 3 h to obtain a slurry; use gravure coating to coat one side of an aluminum foil with a thickness of 13 μm, and bake at 100℃ for 2 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0082] Comparative Example 2: Unmodified toner was used, and the rest was the same as in Example 5;

[0083] Step 1: Preparation of graphene loaded with carbon powder:

[0084] Take 3g of graphene and 50mL of acetone, sonicate for 2.5h, add 0.2g of 1-aminopyrene, stir for 35min, add 0.2g of propyltriethoxysilane isocyanate, react for 8h, centrifuge, wash and dry to obtain modified graphene;

[0085] Take 1g of modified graphene, 1g of carbon powder, and 50mL of deionized water, stir well, add 5wt% ammonia water, adjust the pH value to 8, continue stirring for 60min, centrifuge, wash, and dry to obtain graphene loaded with carbon powder.

[0086] Step 2: Preparation of polyacrylate adhesive:

[0087] Take 80g of lithium methacrylate and 150mL of deionized water, stir evenly at 50℃, add 10g of butyl acrylate and 3g of hexamethylene diisocyanate, react with nitrogen gas for 35min, add 0.5g of ammonium persulfate, heat to 75℃, add 10g of butyl acrylate and 0.2g of divinylbenzene, react for 12h to obtain polyacrylate adhesive;

[0088] Step 3: Preparation of carbon-coated aluminum foil current collector:

[0089] Take 8 kg of polyacrylate binder, 2 kg of deionized water, and 0.1 kg of KH-507 and stir at 50 rpm for 15 min to obtain a modified binder. Mix the modified binder with 2 kg of graphene loaded with carbon powder, 2 kg of deionized water, and 0.02 kg of aziridine and stir for 2.5 h to obtain a slurry. Apply the slurry to one side of an aluminum foil with a thickness of 13 μm using a gravure coating method and bake at 100 °C for 1 min to obtain a carbon-coated aluminum foil current collector with a total thickness of 13.5 μm.

[0090] experiment:

[0091] The performance of carbon-coated aluminum foil current collectors prepared in Examples 1-7 and Comparative Examples 1-2 was tested. The carbon-coated aluminum foil current collectors were cut into 12cm × 5cm samples using a peel strength tester, and the peel strength of the samples was tested. The carbon-coated aluminum foil was used to make batteries, which were charged at different rates with constant current to 3.65V, then charged with constant voltage at a cutoff current of 0.05C, rested for 15 minutes, and then discharged at different rates to 2.5V with a current range of 5-30A. The capacity retention rate under different rates was tested, and the data are shown in the table below.

[0092] Example 1 750 97.80％ 92.51％ Example 2 742 97.67％ 93.23％ Example 3 729 97.55％ 93.76％ Example 4 733 97.73％ 94.21％ Example 5 786 97.82％ 95.67％ Example 6 781 97.84％ 95.48％ Example 7 784 97.84％ 95.62％ Comparative Example 1 485 97.81％ 71.56％ Comparative Example 2 762 97.82％ 94.76％

[0093] Conclusion: The data comparison in the table shows that the peel strength and 20C capacity retention of the carbon-coated aluminum foil current collectors in Examples 1 to 3 are superior to those in Comparative Example 1. Examples 1 to 3 use modified crosslinked slurries, significantly improving the peel strength of the carbon coating and exhibiting excellent rate performance during high-rate charge-discharge processes. Examples 5 to 7 use 1-aminopyrene-modified carbon powder, followed by grafting propyltriethoxysilane isocyanate onto the carbon powder surface. This results in isocyanate groups on the graphene loaded with carbon powder, enhancing the compatibility between the binder and the graphene loaded with carbon powder. This ensures uniform dispersion of the graphene loaded with carbon powder in the polyacrylate binder, enhancing the peel strength of the carbon-coated aluminum foil current collector, improving capacity retention, and thus improving battery performance. Comparative Example 2 uses unmodified carbon powder, resulting in poor dispersion of the graphene loaded with carbon powder in the binder, and the peel strength of the carbon-coated aluminum foil current collector is worse than that in Examples 5 to 7.

[0094] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries, characterized in that: Includes the following steps: Step 1: Take the adhesive, deionized water, and modifier, and stir them evenly to obtain the modified adhesive; Step 2: Mix the modified binder, conductive powder, deionized water, and crosslinking agent evenly to obtain a slurry; Step 3: Coat the slurry onto the surface of the current collector for lithium batteries and bake to obtain a carbon-coated aluminum foil current collector; The slurry comprises the following components, by mass percentage: 10-60% binder, 0.1-2% modifier, 10-30% deionized water, 10-30% conductive powder, and 0.1%-2% crosslinking agent; The adhesive is a polyacrylate adhesive; the preparation method of the polyacrylate adhesive is as follows: take lithium methacrylate and deionized water, stir evenly, add butyl acrylate and hexamethylene diisocyanate, react with nitrogen gas for 30-40 min, add ammonium persulfate, heat to 70-80℃, add butyl acrylate and divinylbenzene, react for 11-13 h to obtain the polyacrylate adhesive. The conductive powder is graphene loaded with carbon powder, and the preparation method of the graphene loaded with carbon powder is as follows: Includes the following steps: S1: Take graphene and acetone, disperse them by ultrasonication, add 1-aminopyrene, stir for 30-40 min, add propyltriethylisocyanate coupling agent, react for 7-9 h, centrifuge, wash and dry to obtain modified graphene. S2: Take modified graphene, modified carbon powder, and deionized water, stir evenly, add ammonia water, continue stirring for 50-70 minutes, centrifuge, wash, and dry to obtain graphene loaded with carbon powder. In S2, the modified toner is prepared by: taking tung oil acid and toluene, stirring evenly to obtain a mixed solution; taking toner and toluene, ultrasonically dispersing, adding to the mixed solution, heating to 95-100℃, reacting for 4-5 hours, filtering, washing, and drying to obtain the modified toner.

2. The method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries according to claim 1, characterized in that: In step one, the adhesive is modified. During the modification process, the adhesive and modifier are stirred, and deionized water is added at the same time. The stirring speed is 10-40 rpm and the stirring time is 10-30 min.

3. The method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries according to claim 1, characterized in that: In step three, the baking temperature is 70-130℃ and the baking time is 20s-3min.

4. The method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries according to claim 1, characterized in that: The modifier is either KH-550 or KH-507.

5. The method for preparing a high-rate carbon-coated aluminum foil current collector for lithium batteries according to claim 1, characterized in that: The crosslinking agent is any one or more of zinc acetate, magnesium acetate, calcium acetate, aziridine, alkoxysilane, and calcium hydroxide.