Functionalized carbon coating slurry for lithium battery and preparation method thereof

Abstract

This invention discloses a functionalized carbon coating slurry for lithium batteries and its preparation method, relating to the field of lithium battery materials technology. The method includes the following steps: preparing a multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion, comprising polymerizing monomers including acrylic acid, butyl acrylate, and ethyl para-aminobenzoate intermediates via free radical copolymerization; preparing a conductive pre-dispersion, comprising mixing a conductive agent, a dispersant, and deionized water under high-speed shear dispersion conditions; and preparing the functionalized carbon coating slurry, comprising mixing the conductive pre-dispersion with the multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion under planetary stirring conditions, followed by static degassing. This invention achieves chemical bonding between the coating components through a multifunctional binder, significantly improving coating adhesion, toughness, and high-temperature stability, while reducing interfacial resistance, thus comprehensively improving the battery's cycle performance, rate performance, and processing reliability.

Description

Technical Field

[0001] This invention relates to the field of lithium battery materials technology, specifically to a functionalized carbon coating slurry for lithium batteries and its preparation method. Background Technology

[0002] In modern high-performance lithium-ion battery technology, to improve the overall electrochemical performance of the battery, a conductive coating is typically pre-coated onto the surface of the positive electrode current collector, forming what is known as carbon-coated aluminum foil. This conductive coating mainly consists of a conductive agent and a binder, and its core function is to reduce the interfacial contact resistance between the current collector and the positive electrode active material, improve the adhesion between the active material and the current collector, and suppress damage to the current collector caused by electrolyte corrosion during battery charging and discharging. In the slurry system for preparing the conductive coating, the binder is a key component that ensures the coating can firmly adhere to the metal current collector and effectively bind the conductive particles to form a stable conductive network. Due to environmental and cost considerations, existing technologies generally use aqueous binder systems, the most common of which is a compound system of styrene-butadiene rubber and sodium carboxymethyl cellulose, or a pure polyacrylic acid aqueous dispersion as the binder.

[0003] However, these traditional binder technologies have inherent drawbacks that are difficult to overcome. First, the bonding mechanism is too simplistic, relying mainly on relatively weak physical forces such as van der Waals forces, hydrogen bonds, and the physical entanglement of polymer chains to bind conductive particles and anchor the metal current collector. This physical force results in limited bonding strength between the coating and the current collector. During subsequent machining processes such as electrode rolling and high-speed winding, the coating is highly susceptible to cracking or even large-area peeling due to mechanical stress. This not only drastically increases the battery's internal resistance and deteriorates its performance, but the detached conductive particles may also puncture the separator, causing internal short circuits and posing a serious safety hazard. Second, traditional binder molecules have poor surface compatibility with conductive carbon materials, lacking strong interfacial interactions. This makes it difficult to disperse conductive particles uniformly and for a long period during the preparation of the conductive slurry. The slurry is prone to sedimentation and stratification during settling, posing challenges to the continuity and stability of the coating process and ultimately affecting the uniformity of the coating thickness. Finally, the conductive network formed by these weak physical forces has a large number of virtual contacts between conductive particles and at the interface between the coating and the current collector, resulting in high interfacial contact resistance. This hinders the rapid and efficient transport of electrons, especially when the battery is charged and discharged at high rates, which causes significant polarization, limits the battery's power performance, and accelerates the battery's capacity decay. Summary of the Invention

[0004] The purpose of this invention is to provide a functionalized carbon coating slurry for lithium batteries and its preparation method, thereby solving the problems existing in the background art.

[0005] To address the aforementioned technical problems, this invention provides a method for preparing a functionalized carbon coating slurry for lithium batteries, comprising the following steps:

[0006] Preparation of a multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion; the preparation of the copolymer aqueous dispersion includes polymerization of monomers including acrylic acid, butyl acrylate and ethyl p-aminobenzoate intermediates via free radical copolymerization;

[0007] Preparation of conductive predispersant; The preparation of conductive predispersant includes mixing conductive agent, dispersant and deionized water under high-speed shear dispersion conditions;

[0008] Preparation of functionalized carbon coating slurry; The preparation of functionalized carbon coating slurry includes mixing a conductive pre-dispersion liquid with a multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion under planetary stirring conditions, and then allowing it to stand to degas;

[0009] The preparation of the ethyl p-aminobenzoate intermediate includes the step of esterification of p-aminobenzoic acid with anhydrous ethanol in the presence of thionyl chloride.

[0010] Preferably, the preparation steps of the ethyl p-aminobenzoate intermediate further include: mixing p-aminobenzoic acid and anhydrous ethanol under ice-water bath conditions at 0-5°C; slowly adding thionyl chloride dropwise through a constant pressure dropping funnel while stirring vigorously, and controlling the temperature of the reaction system to not exceed 10°C; after the addition is complete, continuing to stir the reaction at room temperature; after the reaction is completed, performing rotary evaporation, neutralization with saturated sodium bicarbonate solution, extraction with ethyl acetate, drying with anhydrous sodium sulfate, and solvent removal by rotary evaporation in sequence to obtain the ethyl p-aminobenzoate intermediate.

[0011] Preferably, the preparation steps of the multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion further include: adding acrylic acid, butyl acrylate and ethyl p-aminobenzoate intermediates to deionized water under nitrogen protection and mechanical stirring, and heating to 70-80°C; uniformly adding ammonium persulfate initiator solution through a syringe pump to initiate a free radical copolymerization reaction; after the addition is complete, maintaining the reaction system temperature at 78-82°C for continuous reaction; after the reaction is completed, naturally cooling and adjusting the pH value to 7-8 with ammonia water.

[0012] Preferably, the preparation of the multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion adopts a semi-continuous dropwise polymerization process, including: preparing a monomer preemulsion from acrylic acid, butyl acrylate and ethyl p-aminobenzoate intermediates; and adding the monomer preemulsion and initiator solution to the reaction system in parallel and at a uniform rate using a constant flow pump for polymerization.

[0013] Preferably, the conductive agent includes conductive carbon black and carbon nanotubes; the mass ratio of the solids of conductive carbon black, carbon nanotubes, dispersant and multifunctional aminobenzoate-modified polyacrylate copolymer is (55-65):(35-45):(8-12):(90-110).

[0014] Preferably, the monomers polymerized also include lauryl acrylate.

[0015] Preferably, it further includes:

[0016] A micro-gravure coating process is used to uniformly coat the functionalized carbon coating paste onto the surface of the aluminum foil current collector to form a wet coating.

[0017] The wet coating is cured by gradient heating and baking. This step includes: first baking at 75-85℃ for 8-12 minutes to reduce the moisture content, then heating to 130-150℃ and holding for 25-35 minutes, so that the amino groups on the copolymer react with the oxygen-containing functional groups on the surface of the conductive agent to form chemical amide bonds, and at the same time, the carboxyl groups on the copolymer interact with the surface of the aluminum foil.

[0018] Preferably, the functionalized carbon coating slurry also contains a blocked isocyanate aqueous dispersion accounting for 4-6% of the copolymer solid content; after the curing step of holding at a temperature for 25-35 minutes, a heat anchoring step is added: the temperature is rapidly raised to 165-175℃ and held for 3-7 minutes to deblock the blocked isocyanate and react with the copolymer.

[0019] The present invention also provides a functionalized carbon coating slurry for lithium batteries prepared by a method for preparing a functionalized carbon coating slurry for lithium batteries.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] By ingeniously designing the molecular structure of the adhesive polymer, a variety of specific active functional groups are introduced into its molecular chain. These functional groups can react chemically with the oxide layer on the surface of the metal current collector and the oxygen-containing groups on the surface of the conductive carbon material, forming strong chemical covalent bonds and constructing a powerful three-dimensional cross-linked network structure. This fundamentally solves the problem of weak adhesion between the coating and the current collector, giving the coating extremely excellent adhesion and effectively resisting various mechanical stresses in subsequent production processes.

[0022] The tight and stable connections established by chemical bonding within the coating and at the interface between the coating and the current collector greatly improve the contact quality between the conductive components, effectively reduce the virtual contacts and interface gaps caused by traditional physical bonding, build a smooth and low-resistance channel for electron transmission, significantly reduce the interface contact resistance, thereby effectively suppressing the polarization phenomenon of the battery under high-rate operation, reducing unnecessary energy loss, and providing a solid foundation for improving the power performance of the battery and extending its cycle life under high load.

[0023] By optimizing the binder synthesis process and introducing functional monomers, the overall performance and production applicability of the coating have been further improved. The advanced polymerization process ensures that the molecular weight distribution of the binder product is uniform, guaranteeing the stability between batches of slurry, thereby improving the yield and consistency of large-scale coating production. The flexible segments introduced into the polymer chain endow the coating with excellent toughness, making it less prone to microcracks when subjected to bending or rolling. The introduction of a unique secondary thermosetting crosslinking mechanism enables the coating to maintain a stable structure and adhesion under high-temperature conditions, ensuring the reliability and safety of the battery in fast charging or extreme environments. Detailed Implementation

[0024] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Comparative Example 1

[0026] This comparative example uses the SBR / CMC binder system commonly used in the prior art to prepare carbon-coated aluminum foil; specifically, conductive carbon black, carbon nanotubes, CMC and SBR are dispersed in deionized water at a mass ratio of 60:40:5:5 to prepare a conductive slurry, which is then coated onto aluminum foil and dried; this comparative example is intended as a benchmark to measure the technical effects brought about by the embodiments of the present invention.

[0027] Example 1

[0028] This embodiment provides a method for preparing a functionalized carbon coating slurry for lithium batteries. The method includes preparing a multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion, preparing a conductive pre-dispersion, and preparing a functionalized carbon coating slurry.

[0029] In this method, the intermediate ethyl p-aminobenzoate is first prepared: p-aminobenzoic acid is mixed with anhydrous ethanol under ice-water bath conditions at 0°C. The temperature of the reaction system is controlled to not exceed 10°C during the dropwise addition of thionyl chloride. After the addition is complete, the reaction is continued to be stirred at room temperature for 6 hours. After the reaction is completed, the intermediate ethyl p-aminobenzoate is obtained through steps such as rotary evaporation, neutralization with saturated sodium bicarbonate solution, extraction with ethyl acetate, drying with anhydrous sodium sulfate, and solvent removal by rotary evaporation. It is a pale yellow solid, and its chemical structure is confirmed by 1H NMR spectroscopy, with a yield of 92.5%.

[0030] Subsequently, the multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion was prepared by the following steps: under nitrogen protection, acrylic acid, butyl acrylate and the above-mentioned ethyl p-aminobenzoate intermediate were added to deionized water, and the temperature was raised to 75°C; ammonium persulfate initiator solution was added dropwise at a uniform rate using a syringe pump, and after the addition was completed, the reaction system temperature was maintained at 80°C for 5 hours; after the reaction was completed, the pH value was adjusted to 7.5 with ammonia water to obtain a milky white aqueous dispersion; the solid content of the aqueous dispersion was 45.2 wt%, the weight-average molecular weight was 255,000 g / mol, the polydispersity index was 1.8, and the average particle size was 155 nm as measured by a laser particle size analyzer;

[0031] In the preparation of the conductive predispersant, the conductive agent includes conductive carbon black and carbon nanotubes; when the functionalized carbon coating slurry is finally prepared, the mass ratio of the solids of conductive carbon black, carbon nanotubes, dispersant and multifunctional aminobenzoate-modified polyacrylate copolymer is 60:40:10:100.

[0032] The preparation method also includes subsequent coating and curing steps: coating is performed using a microgravure coating process, and the wet coating is cured by gradient heating and baking. This step includes first baking at 80°C for 10 minutes, then heating to 140°C and holding at that temperature for 30 minutes. The purpose of this curing step is to allow the amino groups on the copolymer to react with the oxygen-containing functional groups on the surface of the conductive agent to form chemical amide bonds, while allowing the carboxyl groups on the copolymer to interact with the surface of the aluminum foil.

[0033] Compared with Comparative Example 1, the functionalized carbon coating slurry prepared by the method of Example 1 has improved coating adhesion because the carboxyl groups introduced in the multifunctional copolymer form an effective chemical reaction with the aluminum foil surface, and the amino groups also form chemical bonds with the carbon material surface. In the rolling process of battery production, this improved adhesion can reduce the risk of coating peeling due to mechanical stress.

[0034] Example 2

[0035] This embodiment provides a method for preparing a functionalized carbon coating slurry for lithium batteries. Its core steps are similar to those in Embodiment 1, with the difference being:

[0036] The preparation of the ethyl p-aminobenzoate intermediate was carried out under ice-water bath conditions at 2°C, and the temperature of the reaction system was controlled not to exceed 8°C when adding thionyl chloride.

[0037] The preparation of the multifunctional aminobenzoate-modified polyacrylate copolymer aqueous dispersion adopted a semi-continuous dropwise polymerization process. The process includes: firstly, preparing a monomer preemulsion from acrylic acid, butyl acrylate and ethyl p-aminobenzoate intermediates; then, adding the monomer preemulsion and initiator solution to the reaction system in parallel and at a uniform rate using a constant flow pump for polymerization; after the dropwise addition is completed, maintaining the reaction system temperature at 78°C for continuous reaction.

[0038] In the functionalized carbon coating slurry, the mass ratio of conductive carbon black, carbon nanotubes, dispersant and copolymer solid is 55:45:8:90;

[0039] In the coating and curing process, the product is first baked at 75°C for 12 minutes, then heated to 130°C and held for 35 minutes.

[0040] Compared to Example 1, the semi-continuous drop-addition polymerization process used in this example helps to obtain binder products with a narrower molecular weight distribution and a more uniform functional group distribution. This is especially important for large-scale production, as it can ensure that the viscosity and rheology of different batches of slurry remain consistent, thereby improving the stability of the coating process and the uniformity of the coating thickness, and reducing the possibility of performance fluctuations in battery products due to batch differences.

[0041] Example 3

[0042] This embodiment provides a method for preparing a functionalized carbon coating slurry for lithium batteries. Its core steps are similar to those in Embodiment 2, with the following differences:

[0043] The preparation of the ethyl p-aminobenzoate intermediate was carried out under ice-water bath conditions at 5°C, and the temperature of the reaction system was controlled not to exceed 10°C when adding thionyl chloride.

[0044] When preparing copolymer water dispersions using a semi-continuous dropwise polymerization process, lauryl acrylate is additionally included in the polymer monomers to introduce flexible segments into the polymer molecular chain.

[0045] In the functionalized carbon coating slurry, the mass ratio of conductive carbon black, carbon nanotubes, dispersant and copolymer solid is 65:35:12:110;

[0046] In the coating and curing process, the product is first baked at 85°C for 8 minutes, then heated to 150°C and held for 25 minutes.

[0047] In this embodiment, the toughness of the coating is improved by introducing lauryl acrylate into the polymer monomer. This flexible modification makes the coating less prone to microcracks when subjected to mechanical stresses such as high-speed winding or high-pressure rolling of battery electrodes. This helps maintain the integrity of the conductive network inside the coating and avoids local resistance increase due to microcracks, thereby ensuring the performance stability of the battery under harsh manufacturing processes.

[0048] Example 4

[0049] This embodiment provides a method for preparing a functionalized carbon coating slurry for lithium batteries. Its core steps are similar to those in Embodiment 2, with the following differences:

[0050] In the functionalized carbon coating slurry, the mass ratio of conductive carbon black, carbon nanotubes, dispersant and copolymer solid is 62:38:10:105;

[0051] In the preparation of functionalized carbon coating slurry, an additional blocked isocyanate water dispersion accounting for 5% by weight of the copolymer solid content was added;

[0052] After the main curing step of coating and curing is completed at 140℃ for 30 minutes, a heat anchoring step is added: the temperature is rapidly raised to 170℃ and held for 5 minutes.

[0053] This embodiment adds a closed isocyanate moisture dispersion to the functionalized carbon coating slurry and adds a thermal anchoring step after the main curing. The purpose is to activate the secondary thermal curing crosslinking mechanism. When the internal temperature of the battery rises under conditions such as fast charging or high-rate discharging, this secondary crosslinking network can effectively resist the creep of the polymer caused by high temperature, maintain the adhesion stability of the coating under long-term high-temperature service conditions, and ensure the safety and reliability of the battery under extreme working scenarios.

[0054] Example 5

[0055] This embodiment provides a method for preparing a functionalized carbon coating slurry for lithium batteries, which combines the optimizations of the aforementioned embodiments:

[0056] The preparation of the multifunctional aminobenzoate-modified polyacrylate copolymer water dispersion adopts a semi-continuous dropwise polymerization process, and the monomers polymerized also include lauryl acrylate.

[0057] In the functionalized carbon coating slurry, the mass ratio of conductive carbon black, carbon nanotubes, dispersant and copolymer solid is 65:35:10:100;

[0058] In the preparation of functionalized carbon coating slurry, an additional blocked isocyanate water dispersion accounting for 6% by weight of the copolymer solid content was added;

[0059] The coating and curing steps include: baking at 85°C for 10 minutes, then raising the temperature to 150°C and holding for 25 minutes, followed by a heat anchoring step, where the temperature is rapidly raised to 175°C and held for 3 minutes to deblock the blocked isocyanate and crosslink it with the copolymer.

[0060] This embodiment combines a semi-continuous dropwise polymerization process, flexible monomer modification, and a secondary thermosetting crosslinking mechanism to provide a solution with excellent overall performance. The coating prepared by this method not only has good batch consistency and mechanical toughness, but also excellent high-temperature adhesion stability. The functionalized carbon coating slurry and the coating formed therefrom can comprehensively meet the multiple challenges from large-scale production and stringent process handling to extreme operating conditions, providing support for the development of lithium batteries with long cycle life, high rate performance, and high safety.

[0061] Performance testing

[0062] The carbon-coated aluminum foils prepared in Comparative Example 1 and Examples 1-5 were used to fabricate NCM811 / graphite system square lithium-ion batteries with a specification of 2Ah under the same conditions, and the following electrochemical and physical performance tests were conducted at 25±2℃.

[0063] 1. 90-degree peel strength

[0064] Cut carbon-coated aluminum foil into 20mm wide samples; use double-sided tape to attach the uncoated side of the sample to a rigid test plate, and clamp the other end to the upper fixture of the tensile testing machine; set the peel angle to 90 degrees, peel at a constant rate of 50mm / min, record and calculate the average tensile force during the peeling process, and finally convert it into peel strength per unit width; test 5 points for each sample and take the average value;

[0065] 2. Interface contact resistance

[0066] The four-probe method was used to test the interfacial contact resistance between the coating and the positive electrode active material under a specific pressure of 10 MPa. Carbon-coated aluminum foil cut to a diameter of 15 mm and the positive electrode sheet were stacked in a special mold. A constant current was applied using a battery resistance tester, and the voltage drop was measured. The result was then calculated according to the formula... Calculate the resistance value, where A is the contact area; test 5 points for each sample and take the average value.

[0067] 3. 500-cycle capacity retention rate

[0068] The assembled battery undergoes formation as follows: At 25°C, it is charged at a constant current of 0.1C to 4.2V, then switched to constant voltage charging until the current is less than 0.05C, and allowed to stand for 30 minutes; then discharged at a constant current of 0.1C to 3.0V; after formation, a cycle test is performed at a rate of 0.5C, i.e., charging at a constant current of 0.5C to 4.2V, switching to constant voltage charging to 0.05C, and then discharging at a constant current of 0.5C to 3.0V; the discharge capacity of the first cycle and the discharge capacity of the 500th cycle are recorded. The cycle capacity retention rate is calculated using the formula: (Discharge capacity of the 500th cycle / Discharge capacity of the 1st cycle) × 100%;

[0069] 4. Adhesion retention rate after high-temperature storage

[0070] First, the initial 90° peel strength of a batch of carbon-coated aluminum foil samples was tested according to Method 1 described above. Then, another batch of the same samples was placed in a constant temperature oven at 80°C and stored for 120 hours. After being removed, the samples were cooled to room temperature and the 90° peel strength was tested again according to Method 1. The formula for calculating the adhesion retention rate after high-temperature storage is: (peel strength after storage / initial peel strength) × 100%.

[0071] The test results are summarized in the table below:

[0072] Table 1 is a summary table of test results for the examples and comparative examples.

[0073] Test Project Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 90-degree peel strength (N / m) 0.4 0.85 0.88 0.92 0.95 0.98 Interfacial contact resistance (mΩ·cm²) 25 16 15.5 15.2 14.5 14.1 Capacity retention rate after 500 cycles (%) (0.5C / 0.5C) 85.1 94.5 95.1 95.8 96.5 97.2 Adhesion retention rate (%) after high temperature storage (80℃, 120h) 65 80 82 84 95 97

[0074] As can be seen from the data in the table above, the functionalized carbon coating slurry prepared in Examples 1-5 of the present invention has significantly better performance indicators than Comparative Example 1, which uses a traditional SBR / CMC binder.

[0075] Compared with Comparative Example 1, Example 1 shows significant improvements in adhesion, interfacial resistance, and cycling performance by introducing a multifunctional adhesive.

[0076] Example 2, based on Example 1, adopts a semi-continuous drip polymerization process, which further stabilizes the product performance and slightly improves various indicators;

[0077] Example 3, by introducing a flexible monomer, showed an advantage in peel strength, indicating that its coating has better toughness and can better adapt to mechanical stress;

[0078] Example 4, by introducing a secondary cross-linking mechanism, exhibits a much higher adhesion retention rate after high-temperature storage than other examples, demonstrating its stability under high-temperature conditions.

[0079] Example 5 integrates various optimization measures and exhibits the best performance in all test indicators, demonstrating the synergistic effect and advanced nature of the technical solution of the present invention.

[0080] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for the preparation of a functionalized carbon-coated slurry coating for lithium batteries, characterized by, The method comprises the following steps: preparing a multifunctional amino benzoate modified polyacrylate copolymer water dispersion; the preparation of the copolymer water dispersion comprises polymerizing monomers including acrylic acid, butyl acrylate and p-amino benzoate intermediate through a free radical copolymerization reaction; preparing a conductive pre-dispersion; the preparation of the conductive pre-dispersion comprises mixing a conductive agent, a dispersant and deionized water under high-speed shearing dispersion conditions; preparing a functionalized carbon coating slurry; the preparation of the functionalized carbon coating slurry comprises mixing the conductive pre-dispersion and the multifunctional amino benzoate modified polyacrylate copolymer water dispersion under planetary stirring conditions, and then standing for defoaming; wherein the preparation of the p-amino benzoate intermediate comprises the step of esterifying p-amino benzoic acid with anhydrous ethanol under the action of thionyl chloride; the preparation of the multifunctional amino benzoate modified polyacrylate copolymer water dispersion adopts a semi-continuous dropping polymerization process, which comprises: preparing monomer pre-emulsion from acrylic acid, butyl acrylate and the p-amino benzoate intermediate; and dropping the monomer pre-emulsion and ammonium persulfate initiator solution into the reaction system in parallel and at a constant speed through a constant-flow pump for polymerization; after the dropping is completed, the temperature of the reaction system is maintained at 78-82℃ for continuous reaction; after the reaction is completed, the system is naturally cooled and the pH value is adjusted to 7-8 with ammonia water; the method further comprises a coating and curing step.

2. A method of preparing a functionalized carbon-coated paste coating for lithium batteries according to claim 1, characterized in that, The preparation step of the p-amino benzoate intermediate further comprises: mixing p-amino benzoic acid and anhydrous ethanol under the condition of an ice water bath at 0-5℃; slowly dropping thionyl chloride through a constant-pressure dropping funnel under vigorous stirring, and controlling the temperature of the reaction system to be no more than 10℃; after the dropping is completed, the reaction is continued at room temperature; after the reaction is completed, rotary evaporation, neutralization with saturated sodium bicarbonate solution, ethyl acetate extraction, drying with anhydrous sodium sulfate and rotary evaporation to remove the solvent are sequentially performed to obtain the p-amino benzoate intermediate.

3. A method of preparing a functionalized carbon-coated paste coating for lithium batteries according to claim 1, characterized in that, The conductive agent comprises conductive carbon black and carbon nanotubes; the mass ratio of the conductive carbon black, the carbon nanotubes, the dispersant and the solid of the multifunctional amino benzoate modified polyacrylate copolymer is (55-65):(35-45):(8-12):(90-110).

4. A method of preparing a functionalized carbon coating paste coating for lithium batteries as claimed in claim 1, wherein, Lauryl acrylate is further included in the polymerized monomers.

5. The method of claim 1, wherein the functionalized carbon coating slurry is prepared by the steps of: a) mixing a carbon source, a binder, and a solvent to form a mixture; b) adding a functionalizing agent to the mixture; c) mixing the mixture to form a functionalized carbon coating slurry; and d) removing the solvent from the functionalized carbon coating slurry. The coating and curing step comprises: uniformly coating the functionalized carbon coating slurry on the surface of an aluminum foil current collector by a micro-gravure coating process to form a wet coating layer; gradient temperature baking and curing of the wet coating layer, which comprises: first baking at 75-85℃ for 8-12 minutes to reduce the moisture content, and then increasing the temperature to 130-150℃ and keeping the temperature for 25-35 minutes to make the amino groups on the copolymer react with the oxygen-containing functional groups on the surface of the conductive agent to form chemical amide bonds, and at the same time, the carboxyl groups on the copolymer form interaction with the surface of the aluminum foil.

6. A method of preparing a functionalized carbon-coated paste coating for lithium batteries according to claim 5, characterized in that, The functionalized carbon coating slurry further comprises a blocked isocyanate water dispersion, which accounts for 4-6% by weight of the solid content of the copolymer; after the curing step of 25-35 minutes, a thermal anchoring step is added: the temperature is quickly raised to 165-175℃ and kept for 3-7 minutes, so that the blocked isocyanate is unblocked and crosslinks with the copolymer.

7. A functionalized carbon coating slurry coating for lithium batteries prepared by the method of any one of claims 1-6.