Carbon coating slurry for improving wettability and preparation method thereof

Abstract

The invention relates to the technical field of lithium batteries, in particular to carbon-coated slurry capable of improving wettability and a preparation method of the carbon-coated slurry. The invention provides a preparation method of carbon-coated slurry with excellent performance, which comprises the following specific steps: firstly, mixing deionized water with a binder with good antibacterial performance, mechanical performance and bonding performance to obtain a low-solid-content glue solution; and then adding a conductive agent into the low-solid-content glue solution, carrying out high-speed dispersion, then adding a wetting agent with high wettability, and carrying out stirring and mechanical grinding to obtain the carbon-coated slurry. The carbon-coated slurry can effectively solve the problems of shrinkage cavities, shrinkage edges and bubble points in the coating process, has the functions of unstable bubbles, defoaming and defoaming, can remarkably reduce the dynamic surface tension, and does not affect the interlayer adhesion.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and specifically to a carbon-coated slurry for improving wettability and a preparation method thereof. Background Art

[0002] Lithium-ion batteries have become the preferred power sources in fields such as current portable electronic devices, energy storage systems, and electric vehicles due to their excellent cycle performance, high energy density, high output voltage, and low self-discharge rate. With the growing global demand for sustainable energy and environmentally friendly transportation, the electric vehicle market has witnessed an explosive growth, which has directly driven the rapid development of the lithium-ion battery industry. Subsequently, there is a huge demand for lithium battery raw materials. Among them, aluminum foil, as a key material for the positive electrode current collector of lithium-ion batteries, has also shown a rapid growth in demand. In lithium-ion batteries, aluminum foil is mainly used as the positive electrode current collector, responsible for collecting the current generated during the battery reaction. The quality of aluminum foil directly affects the performance, safety, and lifespan of the battery. Therefore, the quality of aluminum foil is crucial for the manufacture of lithium-ion batteries. Common aluminum foils include carbon-coated aluminum foil and bare foil. The carbon-coated aluminum foil is formed by coating a layer of carbon material on the surface of the bare foil. This carbon coating can significantly improve the adhesion between the aluminum foil and the electrode material, enhancing the cycle stability and rate performance of the battery. In addition, the carbon coating can also enhance the conductivity of the aluminum foil and reduce the contact resistance, thereby improving the overall performance of the battery. Due to the performance advantages of carbon-coated aluminum foil, its market demand is gradually increasing.

[0003] The current collector is an important component of lithium-ion batteries. It is not only the main site for electron aggregation and transmission but also plays a role in supporting and protecting the electrode and electrolyte. As one of the main materials for the current collector, bare foil is widely used in the production of lithium-ion batteries. Due to the large demand for bare foil in lithium-ion batteries, domestic aluminum foil manufacturers undertake important production tasks. However, there are significant differences in production volume and quality among domestic manufacturers. During the coating process of the carbon-coated slurry on the bare foil, common defects such as shrinkage holes, edge shrinkage, and bubble points occur, which affect the product quality and production efficiency. In addition, during storage and use, especially in an environment with higher humidity, microorganisms (such as bacteria, molds, and fungi) may grow inside the battery and on the surface of the aluminum foil. The growth of these microorganisms not only affects the performance of the battery but may also lead to faults such as battery short circuits and leakage.

[0004] To overcome the defects of the existing technology, the present invention provides a carbon-coated slurry for improving wettability and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a carbon-coated slurry for improving wettability and a preparation method thereof to solve the problems in the existing technology.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] A preparation method of a carbon-coated slurry for improving wettability, comprising the following steps: mixing deionized water with a binder to obtain a low-solid content colloidal solution; adding 1 / 2 of the conductive agent to the low-solid content colloidal solution, and dispersing at a high speed of 2200-2400 rpm / min for 50-60 min; then adding the remaining 1 / 2 of the conductive agent, and dispersing at a high speed of 2200-2400 rpm / min for 50-60 min; then adding a wetting agent, stirring at 13-15 rpm / min for 40-45 min, and then performing mechanical grinding 5-7 times to obtain the carbon-coated slurry.

[0008] Preferably, the wetting agent is any one of isopropanol, isobutanol, ethylene glycol monobutyl ether, tert-butanol, polyether siloxane, and silicone polyether copolymer; the mass ratio of the wetting agent in the carbon-coated slurry is 0.01-20%; the particle size D50 of the carbon-coated slurry < 3 μm, D90 < 10 μm, D97 < 12 μm.

[0009] Preferably, the mass ratio of the binder to the conductive agent is (2-6):(1-5); the binder is any one of acrylic acid, acrylate, methyl methacrylate, polyacrylic acid, modified polyacrylic acid, and waterborne polyurethane; the solid content of the binder is 10-30%; the viscosity of the binder is 400-1500 mPa·s; the conductive agent is any one of carbon black, graphite, graphene, carbon nanotubes, and carbon whiskers, and the particle size is 1-50 μm; among them, the specific surface area of carbon black or graphene with a particle size of 1-50 μm is independently 30-100 m 2 / g, and the dispersion effect is good.

[0010] Preferably, the preparation process of a modified polyacrylic acid binder is as follows:

[0011] Step 1: Add boron nitride powder to the oxidation solution, stir well for 20-25 min, and then wash and dry to obtain pretreated boron nitride; add the pretreated boron nitride to deionized water, stir well for 20-25 min, and then add anhydrous ethanol, ammonia water, and tetraethyl orthosilicate, and continue to stir for 25-30 h to obtain a silicon-coated boron nitride filler; add the silicon-coated boron nitride filler to anhydrous ethanol, then add a silane coupling agent KH570, stir well for 20-25 min, and then reflux at 75-85 °C for 22-27 h. After the reaction, centrifuge, wash, and dry to obtain a modified silicon-coated boron nitride filler;

[0012] Step 2: Add chitosan to distilled water, stir at 85 - 95°C for 40 - 45 min, then add 2,3-epoxypropyltrimethylammonium chloride and continue the reaction for 9 - 11 h. After the reaction, precipitate, wash, and dry to obtain quaternized chitosan; Mix 3-bromo-1-propanol, triphenylphosphine, and N,N-dimethylformamide, stir and react at 125 - 130°C for 70 - 75 h under a nitrogen atmosphere. After the reaction, cool, filter, wash, and vacuum dry to obtain hydroxylated quaternary phosphonium salt;

[0013] Step 3: Mix quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and N,N-dimethylformamide, stir well, then add methacryloyl chloride dropwise and continue the reaction for 3.5 - 4.5 h, then raise the temperature to 25 - 30°C and react for 25 - 30 h. After the reaction, perform rotary evaporation, extraction, and vacuum drying to obtain an allyl antibacterial monomer;

[0014] Step 4: Add acrylic acid, methyl methacrylate, and modified silicon-coated boron nitride filler to sodium hydroxide solution, then bubble with argon for 30 - 40 min, then add ammonium persulfate solution under an argon atmosphere and stir and react at 95 - 100°C for 5 - 7 h, then add the allyl antibacterial monomer and ammonium persulfate solution and continue the reaction for 3 - 4 h. After the reaction, cool and filter to obtain a modified polyacrylic acid binder.

[0015] Preferably, in Step 1, the oxidation solution is prepared from hydrogen peroxide and concentrated sulfuric acid according to a volume ratio of 1:(3.2 - 3.5); the mass-to-volume ratio of pretreated boron nitride and tetraethyl orthosilicate is 1:(0.4 - 0.6); the mass-to-volume ratio of silicon-coated boron nitride filler and silane coupling agent KH570 is 1:(2.5 - 3.0).

[0016] Preferably, in Step 2, the reaction mass ratio of chitosan and 2,3-epoxypropyltrimethylammonium chloride is 1:(3.2 - 3.8); the reaction molar ratio of 3-bromo-1-propanol and triphenylphosphine is 1:(1.2 - 1.4).

[0017] Preferably, in Step 3, the reaction mass ratio of quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and methacryloyl chloride is (3.8 - 4.0):(6.0 - 6.5):3:3.

[0018] Preferably, in Step 4, the reaction mass ratio of acrylic acid, methyl methacrylate, modified silicon-coated boron nitride filler, and allyl antibacterial monomer is 3:1:(0.10 - 0.12):(0.9 - 1.0); the dosage of the initiator ammonium persulfate solution is 0.8 - 1% of the mass of acrylic acid.

[0019] A carbon-coated aluminum foil prepared from the carbon-coated slurry includes the following steps: uniformly coating the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating areal density of 0.6 - 0.8 g / m 2 , and the thickness of the aluminum foil is any one of 9μm, 12μm, 13μm, 15μm, and 20μm.

[0020] Advantages of the present invention:

[0021] The present invention is characterized in that an aqueous slurry is prepared, with water as the solvent. The surface tension of water is relatively high (72 mN / m), which is greater than various common substrates. In an aqueous formulation, a substrate wetting agent needs to be added to reduce the surface tension of the system and increase the wetting and spreading property of the substrate; this is intuitively reflected in the magnitude of the surface tension. Specifically, it is manifested as follows: ① The amphiphilic structure of the wetting agent: The hydrophilic end: Usually polar groups such as hydroxyl (-OH), carboxyl (-COOH), etc., which can bind to water molecules through hydrogen bonds or electrostatic interactions; The hydrophobic end: Usually a non-polar long alkyl chain or aromatic ring, which tends to be away from water and repels polar molecules; ② Adsorbing on the interface and breaking the hydrogen bonds of water molecules: In pure water, water molecules strongly attract each other through hydrogen bonds, forming a relatively high surface tension; after the wetting agent molecules are adsorbed on the liquid surface, the hydrophobic tails extend into the air and the hydrophilic heads face the water, replacing some of the water molecules on the surface; thus, the originally closely arranged water molecules are "dispersed" by the wetting agent molecules, and the hydrogen bonds between water molecules are weakened, resulting in a decrease in the cohesive force on the liquid surface and a consequent decrease in the surface tension; ③ Reducing the surface free energy: The wetting agent molecules form a monolayer film on the liquid surface, and this structure reduces the surface free energy of the liquid; the lower the surface free energy, the more difficult it is for liquid molecules to rearrange back to the original close state, so the surface tension is also smaller.

[0022] The present invention is characterized in that a modified polyacrylic acid binder is prepared. Specifically: In step one, silicon-coated boron nitride filler is obtained by adding boron nitride powder, absolute ethanol, ammonia water, and tetraethyl orthosilicate; then the silicon-coated boron nitride filler is modified with a silane coupling agent KH570 to obtain a modified silicon-coated boron nitride filler. Boron nitride is a material with excellent thermal stability and chemical stability, and silicon coating and modification with a silane coupling agent can further improve its surface properties, making it have better compatibility with the slurry matrix. The addition of this filler has the following advantages: First, boron nitride is a good heat-conducting material, which can improve the heat-conducting performance of the slurry, contribute to the uniform distribution of heat, and reduce the formation of bubbles caused by local overheating. Second, the addition of silicon-coated boron nitride filler can improve the hardness and wear resistance of the coating, which helps to improve the peel strength of the coating. Third, an appropriate amount of silicon-coated boron nitride filler can adjust the viscosity and fluidity of the slurry, making it more controllable during the coating process and reducing the generation of defects.

[0023] In Step 2, by adding chitosan and 2,3-epoxypropyltrimethylammonium chloride, a quaternized chitosan with antibacterial properties is obtained; by adding 3-bromo-1-propanol and triphenylphosphine, a hydroxylated quaternary phosphonium salt with antibacterial properties is obtained; then the quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, N,N-dimethylformamide and methacryloyl chloride are mixed to obtain an allyl antibacterial monomer. This allyl antibacterial monomer contains antibacterial structures such as quaternary ammonium salts, quaternary phosphonium salts and chitosan, so it has excellent antibacterial properties, can effectively prevent the reproduction of microorganisms, reduce the pollution inside the battery, and extend the service life of the battery. Finally, in Step 3, acrylic acid, methyl methacrylate, modified silicon-coated boron nitride filler, ammonium persulfate solution and allyl antibacterial monomer are used as raw materials to prepare a modified polyacrylic acid binder with good antibacterial properties, mechanical properties and bonding properties.

[0024] In summary, the carbon-coated slurry of the present invention has good antibacterial properties, can effectively solve the problems of shrinkage holes, edge shrinkage and bubble points during the coating process, also has the functions of non-foaming stability, defoaming and degassing, can significantly reduce the dynamic surface tension, and does not affect the interlayer adhesion. Detailed implementation mode

[0025] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0026] Source of raw materials:

[0027] The molecular formula of the polyether silicone is R3SiO[SiR2O] n [SiR(CH2CH2O) m (CH2CH(CH3)O) p R’], and the molecular formula of the silicone polyether copolymer is (CH3)3SiO[Si(CH3)(R)O] n Si(CH3)3; boron nitride powder, provided by Liaoning Pengda Technology Co., Ltd., with a particle size of 1000 mesh; chitosan, provided by Sigma-Aldrich Chemical Technology (Shanghai) Co., Ltd., with a deacetylation degree of 97%.

[0028] Example 1: Deionized water was mixed with a binder to obtain a low-solid content glue solution; 1 / 2 of the conductive agent was added to the low-solid content glue solution and dispersed at a high speed of 2400 rpm / min for 60 min; the remaining 1 / 2 of the conductive agent was added and dispersed at a high speed of 2400 rpm / min for 60 min; a wetting agent was added and stirred at 15 rpm / min for 45 min, and then mechanically ground 7 times to obtain a carbon-coated slurry; the carbon-coated slurry was evenly coated on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil was 9 μm;

[0029] The wetting agent was isobutanol; the mass ratio of the wetting agent in the carbon-coated slurry was 20%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent was 1:1; the binder was acrylic acid; the solid content of the binder was 12%; the viscosity of the binder was 600 mPa·s; the conductive agent was carbon black with a particle size of 20 μm.

[0030] Example 2: It was basically the same as Example 1, except that: the wetting agent used tert-butanol

[0031] Deionized water was mixed with a binder to obtain a low-solid content glue solution; 1 / 2 of the conductive agent was added to the low-solid content glue solution and dispersed at a high speed of 2400 rpm / min for 60 min; the remaining 1 / 2 of the conductive agent was added and dispersed at a high speed of 2400 rpm / min for 60 min; a wetting agent was added and stirred at 15 rpm / min for 45 min, and then mechanically ground 7 times to obtain a carbon-coated slurry; the carbon-coated slurry was evenly coated on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil was 9 μm;

[0032] The wetting agent was tert-butanol; the mass ratio of the wetting agent in the carbon-coated slurry was 20%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent was 1:1; the binder was acrylic acid; the solid content of the binder was 12%; the viscosity of the binder was 600 mPa·s; the conductive agent was carbon black with a particle size of 20 μm.

[0033] Example 3: It was basically the same as Example 1, except that: the wetting agent used ethylene glycol monobutyl ether, and the proportion of the wetting agent in the carbon-coated slurry was 1%

[0034] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; evenly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0035] The wetting agent is ethylene glycol monobutyl ether; the mass ratio of the wetting agent in the carbon-coated slurry is 1%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0036] Example 4: It is basically the same as Example 1, except that: the wetting agent used is ethylene glycol monobutyl ether, and the proportion of the wetting agent in the carbon-coated slurry is 2%

[0037] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; evenly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0038] The wetting agent is ethylene glycol monobutyl ether; the mass ratio of the wetting agent in the carbon-coated slurry is 2%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0039] Example 5: It is basically the same as Example 1, except that: the wetting agent used is ethylene glycol monobutyl ether, and the proportion of the wetting agent in the carbon-coated slurry is 3%

[0040] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 The carbon-coated aluminum foil has an aluminum foil thickness of 9 μm;

[0041] The wetting agent is ethylene glycol monobutyl ether; the mass ratio of the wetting agent in the carbon-coated slurry is 3%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0042] Example 6: It is basically the same as Example 1, except that: the wetting agent used is polyether siloxane, and the proportion of the wetting agent in the carbon-coated slurry is 0.03%

[0043] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 The carbon-coated aluminum foil has an aluminum foil thickness of 9 μm;

[0044] The wetting agent is polyether siloxane; the mass ratio of the wetting agent in the carbon-coated slurry is 0.03%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0045] Example 7: It is basically the same as Example 1, except that: the wetting agent used is polyether siloxane, and the proportion of the wetting agent in the carbon-coated slurry is 0.06%

[0046] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0047] The wetting agent is polyether siloxane; the mass ratio of the wetting agent in the carbon-coated slurry is 0.06%; the particle size D50 of the carbon-coated slurry is < 3 μm, D90 is < 10 μm, and D97 is < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0048] Example 8: It is basically the same as Example 1, except that: the wetting agent uses a silicone polyether copolymer, and the proportion of the wetting agent in the carbon-coated slurry is 0.5%

[0049] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0050] The wetting agent is a silicone polyether copolymer; the mass ratio of the wetting agent in the carbon-coated slurry is 0.5%; the particle size D50 of the carbon-coated slurry is < 3 μm, D90 is < 10 μm, and D97 is < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0051] Example 9: It is basically the same as Example 1, except that: the wetting agent uses a silicone polyether copolymer, and the proportion of the wetting agent in the carbon-coated slurry is 1%

[0052] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0053] The wetting agent is a silicone polyether copolymer; the mass ratio of the wetting agent in the carbon-coated slurry is 1%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0054] Example 10: Basically the same as Example 1, the difference is that: the wetting agent uses a silicone polyether copolymer, and the proportion of the wetting agent in the carbon-coated slurry is 1.5%

[0055] Mix deionized water with a binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then conduct mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0056] The wetting agent is a silicone polyether copolymer; the mass ratio of the wetting agent in the carbon-coated slurry is 1.5%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0057] Example 11: Basically the same as Example 1, the difference is that: the wetting agent uses isopropyl alcohol

[0058] Mix deionized water with a binder to obtain a low-solid-content glue solution; add 1 / 2 of the conductive agent to the low-solid-content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then perform mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 wherein the thickness of the aluminum foil is 9 μm;

[0059] The wetting agent is isopropyl alcohol; the mass ratio of the wetting agent in the carbon-coated slurry is 20%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is acrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm.

[0060] Example 12: It is basically the same as Example 9, except that: the binder is modified polyacrylic acid

[0061] Step 1: Mix deionized water with a binder to obtain a low-solid-content glue solution; add 1 / 2 of the conductive agent to the low-solid-content glue solution and disperse it at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm / min for 60 min; then add a wetting agent and stir it at 15 rpm / min for 45 min, and then perform mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 wherein the thickness of the aluminum foil is 9 μm;

[0062] Step 2: The wetting agent is isobutanol; the mass ratio of the wetting agent in the carbon-coated slurry is 20%; the particle size of the carbon-coated slurry D50 < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is modified polyacrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm;

[0063] Step 3: The preparation process of modified polyacrylic acid is as follows:

[0064] Add boron nitride powder to the oxidation solution, stir well for 25 min, then wash and dry to obtain pretreated boron nitride; add the pretreated boron nitride to deionized water, stir well for 25 min, then add absolute ethanol, ammonia water, and tetraethyl orthosilicate, and continue to stir for 30 h to obtain silicon-coated boron nitride filler; add the silicon-coated boron nitride filler to absolute ethanol, then add silane coupling agent KH570, stir well for 25 min, and then reflux at 85 °C for 27 h. After the reaction, centrifuge, wash, and dry to obtain modified silicon-coated boron nitride filler; the oxidation solution is prepared from hydrogen peroxide and concentrated sulfuric acid according to a volume ratio of 1:3.2; the mass-volume ratio of the pretreated boron nitride to tetraethyl orthosilicate is 1:0.5; the mass-volume ratio of the silicon-coated boron nitride filler to silane coupling agent KH570 is 1:2.7;

[0065] Add chitosan to distilled water, stir at 95 °C for 45 min, then add 2,3-epoxypropyltrimethylammonium chloride and continue to react for 11 h. After the reaction, precipitate, wash, and dry to obtain quaternized chitosan; mix 3-bromo-1-propanol, triphenylphosphine, and N,N-dimethylformamide, stir and react at 130 °C for 75 h in a nitrogen environment. After the reaction, cool, filter, wash, and vacuum dry to obtain hydroxylated quaternary phosphonium salt; the reaction mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:3.5; the reaction molar ratio of 3-bromo-1-propanol to triphenylphosphine is 1:1.3;

[0066] Mix quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and N,N-dimethylformamide, stir well, then add methacryloyl chloride dropwise and continue to react for 4.5 h, then raise the temperature to 30 °C and react for 30 h. After the reaction, perform rotary evaporation, extraction, and vacuum drying to obtain an allyl antibacterial monomer; the reaction mass ratio of quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and methacryloyl chloride is 3.9:6.2:3:3;

[0067] Add acrylic acid, methyl methacrylate, and modified silicon-coated boron nitride filler to sodium hydroxide solution, then bubble with argon for 40 min, then add ammonium persulfate solution in an argon environment and stir and react at 100 °C for 7 h, then add the allyl antibacterial monomer and ammonium persulfate solution and continue to react for 4 h. After the reaction, cool and filter to obtain a modified polyacrylic acid binder; the reaction mass ratio of acrylic acid, methyl methacrylate, modified silicon-coated boron nitride filler, and allyl antibacterial monomer is 3:1:0.11:0.95; the dosage of the initiator ammonium persulfate solution is 1% of the mass of acrylic acid.

[0068] Comparative Example 1: When preparing the carbon-coated slurry, no wetting agent is added, and the rest is the same as in Example 12

[0069] Step 1: Mix deionized water with a binder to obtain a low-solid content colloidal solution; add 1 / 2 of the conductive agent to the low-solid content colloidal solution, disperse at a high speed of 2400 rpm / min for 60 min; then add the remaining 1 / 2 of the conductive agent, disperse at a high speed of 2400 rpm / min for 60 min; then perform mechanical grinding 7 times to obtain a carbon-coated slurry; uniformly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0070] Step 2: The particle size D50 of the carbon-coated slurry is < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is modified polyacrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm;

[0071] Step 3: The preparation process of the modified polyacrylic acid is as follows:

[0072] Add boron nitride powder to the oxidation solution, stir well for 25 min, then wash and dry to obtain pretreated boron nitride; add the pretreated boron nitride to deionized water, stir well for 25 min, then add anhydrous ethanol, ammonia water, and tetraethyl orthosilicate, and continue to stir for 30 h to obtain a silicon-coated boron nitride filler; add the silicon-coated boron nitride filler to anhydrous ethanol, then add silane coupling agent KH570, stir well for 25 min and then reflux at 85 °C for 27 h, after the reaction is completed, centrifuge, wash, and dry to obtain a modified silicon-coated boron nitride filler; the oxidation solution is prepared from hydrogen peroxide and concentrated sulfuric acid according to a volume ratio of 1:3.2; the mass-volume ratio of the pretreated boron nitride to tetraethyl orthosilicate is 1:0.5; the mass-volume ratio of the silicon-coated boron nitride filler to silane coupling agent KH570 is 1:2.7;

[0073] Add chitosan to distilled water, stir at 95 °C for 45 min, then add 2,3-epoxypropyltrimethylammonium chloride and continue the reaction for 11 h, after the reaction is completed, precipitate, wash, and dry to obtain quaternized chitosan; mix 3-bromo-1-propanol, triphenylphosphine, and N,N-dimethylformamide, stir and react at 130 °C in a nitrogen environment for 75 h, after the reaction is completed, cool, filter, wash, and vacuum dry to obtain hydroxylated quaternary phosphonium salt; the reaction mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:3.5; the reaction molar ratio of 3-bromo-1-propanol to triphenylphosphine is 1:1.3;

[0074] Quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine and N,N-dimethylformamide were mixed, and after stirring thoroughly, methacryloyl chloride was added dropwise and the reaction continued for 4.5 h. Then the temperature was raised to 30 °C and the reaction continued for 30 h. After the reaction, rotary evaporation, extraction and vacuum drying were carried out to obtain an allyl antibacterial monomer; the reaction mass ratio of quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine and methacryloyl chloride was 3.9:6.2:3:3;

[0075] Acrylic acid, methyl methacrylate and modified silicon-coated boron nitride filler were added to sodium hydroxide solution, and then argon was bubbled for 40 min. Then ammonium persulfate solution was added under an argon atmosphere and stirred at 100 °C for 7 h. Then the allyl antibacterial monomer and ammonium persulfate solution were added and the reaction continued for 4 h. After the reaction, cooling and filtration were carried out to obtain a modified polyacrylic acid binder; among them, the reaction mass ratio of acrylic acid, methyl methacrylate, modified silicon-coated boron nitride filler and allyl antibacterial monomer was 3:1:0.11:0.95; the dosage of the initiator ammonium persulfate solution was 1% of the mass of acrylic acid.

[0076] Comparative Example 2: When preparing the carbon-coated slurry, two wetting agents were added, and the rest was the same as in Example 12

[0077] Step 1: Deionized water and the binder were mixed to obtain a low-solid content glue solution; 1 / 2 of the conductive agent was added to the low-solid content glue solution and dispersed at a high speed of 2400 rpm / min for 60 min; then the remaining 1 / 2 of the conductive agent was added and dispersed at a high speed of 2400 rpm / min for 60 min; then the wetting agent was added and stirred at 15 rpm / min for 45 min, and then mechanically ground 7 times to obtain a carbon-coated slurry; the carbon-coated slurry was evenly coated on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil was 9 μm;

[0078] Step 2: The wetting agent was isobutanol and silicone polyether copolymer, and the mass ratio of isobutanol in the carbon-coated slurry was 20%; the mass ratio of the silicone polyether copolymer in the carbon-coated slurry was 1.5%; the particle size D50 of the carbon-coated slurry was < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder and the conductive agent was 1:1; the binder was modified polyacrylic acid; the solid content of the binder was 12%; the viscosity of the binder was 600 mPa·s; the conductive agent was carbon black with a particle size of 20 μm;

[0079] Step 3: The preparation process of the modified polyacrylic acid was as follows:

[0080] Add boron nitride powder to the oxidation solution, stir well for 25 min, then wash and dry to obtain pretreated boron nitride; add the pretreated boron nitride to deionized water, stir well for 25 min, then add anhydrous ethanol, ammonia water, and tetraethyl orthosilicate, and continue stirring for 30 h to obtain silicon-coated boron nitride filler; add the silicon-coated boron nitride filler to anhydrous ethanol, then add silane coupling agent KH570, stir well for 25 min, and then reflux at 85 °C for 27 h. After the reaction, centrifuge, wash, and dry to obtain modified silicon-coated boron nitride filler; the oxidation solution is prepared from hydrogen peroxide and concentrated sulfuric acid according to a volume ratio of 1:3.2; the mass-to-volume ratio of pretreated boron nitride to tetraethyl orthosilicate is 1:0.5; the mass-to-volume ratio of silicon-coated boron nitride filler to silane coupling agent KH570 is 1:2.7;

[0081] Add chitosan to distilled water, stir at 95 °C for 45 min, then add 2,3-epoxypropyltrimethylammonium chloride and continue reacting for 11 h. After the reaction, precipitate, wash, and dry to obtain quaternized chitosan; mix 3-bromo-1-propanol, triphenylphosphine, and N,N-dimethylformamide, stir and react at 130 °C for 75 h under a nitrogen atmosphere. After the reaction, cool, filter, wash, and vacuum dry to obtain hydroxylated quaternary phosphonium salt; the reaction mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:3.5; the reaction molar ratio of 3-bromo-1-propanol to triphenylphosphine is 1:1.3;

[0082] Mix quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and N,N-dimethylformamide, stir well, then dropwise add methacryloyl chloride and continue reacting for 4.5 h, then raise the temperature to 30 °C and react for 30 h. After the reaction, perform rotary evaporation, extraction, and vacuum drying to obtain an allyl antibacterial monomer; the reaction mass ratio of quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and methacryloyl chloride is 3.9:6.2:3:3;

[0083] Add acrylic acid, methyl methacrylate, and modified silicon-coated boron nitride filler to sodium hydroxide solution, then bubble argon for 40 min, then add ammonium persulfate solution under an argon atmosphere and stir and react at 100 °C for 7 h, then add the allyl antibacterial monomer and ammonium persulfate solution and continue reacting for 4 h. After the reaction, cool and filter to obtain a modified polyacrylic acid binder; the reaction mass ratio of acrylic acid, methyl methacrylate, modified silicon-coated boron nitride filler, and allyl antibacterial monomer is 3:1:0.11:0.95; the dosage of the initiator ammonium persulfate solution is 1% of the mass of acrylic acid.

[0084] Comparative Example 3: When preparing the modified polyacrylic acid binder, the modified silicon-coated boron nitride filler was removed, and the rest was the same as in Example 12: Step 1: Deionized water and the binder were mixed to obtain a low-solid content glue solution; 1 / 2 of the conductive agent was added to the low-solid content glue solution, and high-speed dispersion was carried out at 2400 rpm for 60 min; then the remaining 1 / 2 of the conductive agent was added, and high-speed dispersion was carried out at 2400 rpm for 60 min; then a wetting agent was added, and stirring was carried out at 15 rpm for 45 min, and then mechanical grinding was carried out 7 times to obtain a carbon-coated slurry; the carbon-coated slurry was evenly coated on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil was 9 μm;

[0085] Step 2: The wetting agent was isobutanol; the mass ratio of the wetting agent in the carbon-coated slurry was 20%; the particle size D50 of the carbon-coated slurry < 3 μm, D90 < 10 μm, D97 < 12 μm; the mass ratio of the binder to the conductive agent was 1:1; the binder was modified polyacrylic acid; the solid content of the binder was 12%; the viscosity of the binder was 600 mPa·s; the conductive agent was carbon black with a particle size of 20 μm;

[0086] Step 3: The preparation process of the modified polyacrylic acid was as follows:

[0087] Chitosan was added to distilled water, and stirring was carried out at 95 °C for 45 min, then 2,3-epoxypropyltrimethylammonium chloride was added and the reaction continued for 11 h. After the reaction ended, precipitation, washing, and drying were carried out to obtain quaternized chitosan; 3-bromo-1-propanol, triphenylphosphine, and N,N-dimethylformamide were mixed, and stirring reaction was carried out at 130 °C in a nitrogen environment for 75 h. After the reaction ended, cooling, filtration, washing, and vacuum drying were carried out to obtain hydroxylated quaternary phosphonium salt; the reaction mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride was 1:3.5; the reaction molar ratio of 3-bromo-1-propanol to triphenylphosphine was 1:1.3;

[0088] Quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and N,N-dimethylformamide were mixed, and after sufficient stirring, methacryloyl chloride was added dropwise and the reaction continued for 4.5 h, then the temperature was raised to 30 °C and the reaction continued for 30 h. After the reaction ended, rotary evaporation, extraction, and vacuum drying were carried out to obtain an allyl antibacterial monomer; the reaction mass ratio of quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine, and methacryloyl chloride was 3.9:6.2:3:3;

[0089] Add acrylic acid and methyl methacrylate to the sodium hydroxide solution, then introduce argon gas for bubbling for 40 min. Then add ammonium persulfate solution under an argon atmosphere and stir and react at 100 °C for 7 h. Then add allyl antibacterial monomer and ammonium persulfate solution and continue to react for 4 h. After the reaction is completed, cool and filter to obtain a modified polyacrylic acid binder; the reaction mass ratio of acrylic acid, methyl methacrylate, and allyl antibacterial monomer is 3:1:0.95; the dosage of the initiator ammonium persulfate solution is 1% of the mass of acrylic acid.

[0090] Comparative Example 4: When preparing the modified polyacrylic acid binder, remove the allyl antibacterial monomer, and the rest is the same as in Example 12: Step 1: Mix deionized water and the binder to obtain a low-solid content glue solution; add 1 / 2 of the conductive agent to the low-solid content glue solution and disperse it at a high speed of 2400 rpm for 60 min; then add the remaining 1 / 2 of the conductive agent and disperse it at a high speed of 2400 rpm for 60 min; then add the wetting agent and stir at 15 rpm for 45 min, and then carry out mechanical grinding 7 times to obtain a carbon-coated slurry; evenly coat the carbon-coated slurry on the surface of the aluminum foil to obtain a carbon-coated aluminum foil with a coating surface density of 0.8 g / m 2 where the thickness of the aluminum foil is 9 μm;

[0091] Step 2: The wetting agent is isobutanol; the mass ratio of the wetting agent in the carbon-coated slurry is 20%; the particle size D50 of the carbon-coated slurry is < 3 μm, D90 is < 10 μm, and D97 is < 12 μm; the mass ratio of the binder to the conductive agent is 1:1; the binder is modified polyacrylic acid; the solid content of the binder is 12%; the viscosity of the binder is 600 mPa·s; the conductive agent is carbon black with a particle size of 20 μm;

[0092] Step 3: The preparation process of the modified polyacrylic acid is as follows:

[0093] Add boron nitride powder to the oxidation solution, stir well for 25 min, then wash and dry to obtain pretreated boron nitride; add the pretreated boron nitride to deionized water, stir well for 25 min, then add anhydrous ethanol, ammonia water, and tetraethyl orthosilicate, and continue to stir for 30 h to obtain a silicon-coated boron nitride filler; add the silicon-coated boron nitride filler to anhydrous ethanol, then add the silane coupling agent KH570, stir well for 25 min, and then reflux and react at 85 °C for 27 h. After the reaction is completed, centrifuge, wash, and dry to obtain a modified silicon-coated boron nitride filler; the oxidation solution is prepared from hydrogen peroxide and concentrated sulfuric acid according to a volume ratio of 1:3.2; the mass-to-volume ratio of the pretreated boron nitride to tetraethyl orthosilicate is 1:0.5; the mass-to-volume ratio of the silicon-coated boron nitride filler to the silane coupling agent KH570 is 1:2.7;

[0094] Acrylic acid, methyl methacrylate, and modified silicon-coated boron nitride filler were added to a sodium hydroxide solution, and then argon was bubbled through for 40 min. Subsequently, an ammonium persulfate solution was added under an argon atmosphere, and the mixture was stirred and reacted at 100 °C for 7 h. After the reaction ended, it was cooled and filtered to obtain a modified polyacrylic acid binder; the reaction mass ratio of acrylic acid, methyl methacrylate, and modified silicon-coated boron nitride filler was 3:1:0.11; the amount of the initiator ammonium persulfate solution was 1% of the mass of acrylic acid.

[0095] Detection test:

[0096] Outlet surface tension test: It was tested using a surface tension meter. The carbon-coated slurry prepared in the present invention was filled into a glassware and placed horizontally. The platinum sheet was in contact with the liquid surface. After 5 min of timing, the value displayed by the instrument was the surface tension value; the test temperature and humidity were 25 °C, RH ≤ 60%.

[0097] 1 m of the film surface 2 Shrinkage hole test: Randomly take 1 m 2 of the carbon-coated aluminum foil prepared in the present invention and visually count the number of shrinkage holes.

[0098] Coating peel strength test: It was tested using a peel tester. The carbon-coated aluminum foil prepared in the present invention was cut into a specimen of 15 * 3 cm, and the cut specimen was pasted onto a peel board; a 3M transparent tape with a width of 2 cm was prepared and pasted onto the carbon-coated aluminum foil, and it was stretched horizontally at 180° at a constant speed (200 mm / min) for 100 mm. The maximum value within the interval was taken as the peel strength; the test temperature and humidity were 25 °C, RH ≤ 60%.

[0099] Antibacterial test: The carbon-coated slurry prepared in the present invention was coated onto a glass sheet, and after drying at room temperature, a sample sheet was obtained; then, a blank petri dish containing agar was taken, and a suspension of Staphylococcus aureus was added thereto. After spreading evenly, the sample sheet was applied. After culturing at 30 °C for 30 h, the diameter of the antibacterial zone on the agar was observed. The results are shown in Table 1 below:

[0100] Table 1: Data tests of Examples 1-12 and Comparative Examples 1-4

[0101]

[0102]

[0103] Test standard: The number of shrinkage holes and air bubble points on the film surface ≤ 3, the surface tension < 30 mN / m, and the coating peel strength > 400 N / m;

[0104] Results analysis of Examples 1 to 12: Examples 1 to 5, 11: surface tension does not meet the requirements; Examples 6 to 8, 11: shrinkage holes and bubble points do not meet the requirements; Examples 9, 10, 11: the diameter of the antibacterial zone is too small; Considering comprehensively, Example 12 has the best effect.

[0105] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0106] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used 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 perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a carbon coating slurry with improved wettability, characterized in that: The following steps are involved: Mix deionized water and binder to obtain low-solid glue solution; add 1 / 2 of the conductive agent to the low-solid glue solution, and disperse at high speed of 2200-2400rpm / min for 50-60min; then add the remaining 1 / 2 of the conductive agent. High-speed dispersion at 2200-2400 rpm / min for 50-60 min; then adding a wetting agent, stirring at 13-15 rpm / min for 40-45 min, and then mechanical grinding for 5-7 times to obtain a carbon-coated slurry.

2. The method for preparing a carbon coating slurry with improved wettability according to claim 1, characterized in that: The wetting agent is any one of isopropyl alcohol, isobutyl alcohol, ethylene glycol butyl ether, tert-butyl alcohol, polyether siloxane, and silicone polyether copolymer; the mass proportion of the wetting agent in the carbon coating slurry is 0.01-20%; the particle size of the carbon coating slurry D50 is less than 3μm, D90 is less than 10μm, and D97 is less than 12μm.

3. The method for preparing a carbon coating slurry with improved wettability according to claim 1, characterized in that: The mass ratio of the binder to the conductive agent is (2-6): (1-5); the binder is any one of acrylic acid, acrylate, methyl methacrylate, polyacrylic acid, modified polyacrylic acid, and waterborne polyurethane; the solid content of the binder is 10-30%; the viscosity of the binder is 400-1500mPa.s; the conductive agent is any one of carbon black, graphite, graphene, carbon nanotubes, and carbon whiskers, and the particle size is 1-50μm.

4. The method for preparing a carbon coating slurry with improved wettability according to claim 3, characterized in that: A preparation process of a modified polyacrylic acid binder is: Step 1: Add boron nitride powder to the oxidation solution, stir thoroughly for 20-25 minutes, wash and dry to obtain pretreated boron nitride; add the pretreated boron nitride to deionized water, stir thoroughly for 20-25 minutes, add anhydrous ethanol, ammonia water and tetraethyl orthosilicate, and continue stirring for 25-30 hours to obtain silicon-coated boron nitride filler; add the silicon-coated boron nitride filler to anhydrous ethanol, add silane coupling agent KH570, stir thoroughly for 20-25 minutes, and then reflux at 75-85°C for 22-27 hours. After the reaction is completed, centrifuge, wash and dry to obtain modified silicon-coated boron nitride filler; Step 2: Add chitosan to distilled water, stir at 85-95°C for 40-45min, then add 2,3-epoxypropyltrimethylammonium chloride and continue to react for 9-11h. After the reaction is completed, precipitate, wash and dry to obtain quaternized chitosan; mix 3-bromo-1-propanol, triphenylphosphine and N,N-dimethylformamide, stir and react at 125-130°C in a nitrogen environment for 70-75h. After the reaction is completed, cool, filter, wash and vacuum dry to obtain a hydroxylated quaternary phosphonium salt; Step 3: Mix quaternary ammonium chitosan, hydroxylated quaternary phosphonium salt, triethylamine and N,N-dimethylformamide, add methacryloyl chloride dropwise after sufficient stirring and continue to react for 3.5-4.5 hours, then heat to 25-30°C and react for 25-30 hours. After the reaction is completed, perform rotary evaporation, extraction and vacuum drying to obtain an propylene antibacterial monomer; Step 4: Add acrylic acid, methyl methacrylate, and modified silicon-coated boron nitride filler to a sodium hydroxide solution, then introduce argon gas for 30-40 minutes, then add ammonium persulfate solution under an argon environment and stir to react at 95-100°C for 5-7 hours, then add propylene antibacterial monomer and ammonium persulfate solution and continue to react for 3-4 hours. After the reaction is completed, cool and filter to obtain a modified polyacrylic acid binder.

5. The method for preparing a carbon coating slurry with improved wettability according to claim 4, characterized in that: In step 1, the oxidizing liquid is prepared by hydrogen peroxide and concentrated sulfuric acid in a volume ratio of 1: (3.2-3.5); the mass volume ratio of pretreated boron nitride and ethyl orthosilicate is 1: (0.4-0.6); the mass volume ratio of silicon-coated boron nitride filler and silane coupling agent KH570 is 1: (2.5-3.0).

6. The method for preparing a carbon coating slurry with improved wettability according to claim 4, characterized in that: In step 2, the reaction mass ratio of chitosan and 2,3-epoxypropyltrimethylammonium chloride is 1:(3.2-3.8); the reaction molar ratio of 3-bromo-1-propanol and triphenylphosphine is 1:(1.2-1.4).

7. The method for preparing a carbon coating slurry with improved wettability according to claim 4, characterized in that: In step 3, the reaction mass ratio of quaternized chitosan, hydroxylated quaternary phosphonium salt, triethylamine and methacryloyl chloride is (3.8-4.0):(6.0-6.5):3:

3.

8. The method for preparing a carbon coating slurry with improved wettability according to claim 4, characterized in that: In step 4, the reaction mass ratio of acrylic acid, methyl methacrylate, modified silicon-coated boron nitride filler, and acrylic antibacterial monomer is 3:1:(0.10-0.12):(0.9-1.0); the amount of initiator ammonium persulfate solution used is 0.8-1% of the mass of acrylic acid.

9. A carbon coating slurry for improving wettability, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. A carbon-coated aluminum foil prepared according to the carbon-coated slurry according to claim 9, characterized in that: The method comprises the following steps: uniformly coating the carbon coating slurry on the surface of the aluminum foil to obtain a coating surface density of 0.6-0.8 g / m 2 The carbon-coated aluminum foil has a thickness of any one of 9 μm, 12 μm, 13 μm, 15 μm, and 20 μm.

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