A modified conductive carbon material, and a preparation method and application thereof

Abstract

The application provides a modified conductive carbon material and a preparation method and application thereof, and the preparation raw material of the modified conductive carbon material comprises, in terms of weight parts, 60-80 parts of methyl methacrylate, 10-20 parts of butyl acrylate, 1-5 parts of a polymerizable silane coupling agent, 5-10 parts of a conductive carbon material, 0.1-0.2 parts of a first initiator, 0.1-0.3 parts of a second initiator, 1-10 parts of a first solvent and 0.1-1 parts of a second solvent. The methyl methacrylate-butyl acrylate-polymerizable silane coupling agent copolymer is used for surface modification of the conductive carbon material, physical action and chemical bonding of the conductive carbon material are caused through a polar bond, the surface free energy of the carbon material powder is reduced, the affinity with butadiene-styrene latex is increased, the butadiene-styrene latex tends to be stable in the slurry, the coating film surface stripe problem caused by the instability of the butadiene-styrene latex in the slurry is improved, and the water resistance is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion batteries, and in particular relates to a modified conductive carbon material and a preparation method and application thereof. Background Art

[0002] During the manufacturing process of lithium-ion batteries and sodium-ion batteries, in order to improve the current collection intensity of the current collector for the active material and the adhesion performance of the active material to the electrode, a layer of conductive material is first coated on the surface of the current collector, and then the active material is directly coated on the surface of the current collector with conductive material when manufacturing the electrode.

[0003] CN111430723A provides a lithium-replenishing current collector, its preparation method, application, negative electrode plate and lithium-ion battery, wherein the lithium-replenishing current collector includes a current collector body and a lithium-replenishing material layer; the current collector body includes a first carbon coating layer, a base layer and a second carbon coating layer arranged in sequence, and the first carbon coating layer, the base layer and the second carbon coating layer are tightly attached to and fixedly connected to each other; a plurality of through holes are provided on the first carbon coating layer at intervals, and the plurality of through holes all penetrate the base layer and the second carbon coating layer; the lithium-replenishing material layer is filled in the plurality of through holes, and the lithium-replenishing current collector contains a lithium-replenishing substance, which can achieve precise lithium replenishment of the silicon-carbon negative electrode while reducing the internal resistance of the plate after lithium replenishment, thereby improving the rate performance and cycle performance of the battery, but its water resistance is poor and its application range is limited.

[0004] CN110034302A discloses an ultra-thin carbon-coated current collector and its preparation method, comprising the following steps: cleaning the current collector and then subjecting it to a positive charge treatment to obtain a current collector with a positive surface charge; dissolving a binder, sequentially adding an anionic surfactant and a conductive agent, and stirring to form a negatively charged aqueous conductive slurry; ultrasonically atomizing the negatively charged aqueous conductive slurry into an aerosol, electrostatically depositing it onto the positively charged current collector, and then drying to obtain an ultra-thin carbon-coated current collector. The current collector prepared by this method has a thin and uniform conductive coating, strong adhesion, and good electrical conductivity, but its water resistance is poor, limiting its scope of application.

[0005] In response to environmental concerns, lithium-ion secondary batteries are shifting from oil-based cathode active material coatings to aqueous systems. In the more recently developed aqueous secondary batteries, sodium-ion batteries, both the positive and negative electrode active material coatings are aqueous. This requires the current collector coating to possess strong water resistance.

[0006] CN113140706A relates to the technical field of battery production process, and provides a battery carbon coating process and a preparation method of a lithium ion battery. The battery carbon coating process comprises the following steps: S1, preparing a carbon coating slurry, wherein the carbon coating slurry comprises 10-20% of conductive carbon black, 70-80% of deionized water, 5-10% of butadiene styrene rubber and 2-4% of a dispersing agent by mass percentage; and S2, spraying the carbon coating slurry to the inner surface of a small-size cylindrical steel shell or a cylindrical aluminum shell of a lithium ion battery. The preparation method of the lithium ion battery is to perform carbon coating treatment on the inner surface of the small cylindrical steel shell or the small cylindrical aluminum shell, so that the electronic conductivity of the current collector and the active material of the steel shell or the aluminum shell is improved, the internal resistance of the lithium ion battery is reduced, the capacity of the lithium ion battery is improved, and the space utilization inside the lithium ion battery is increased. However, due to the poor affinity of butadiene styrene rubber and conductive agent, the phenomenon of blue floating easily occurs, and the problem of uneven material on the coating roll occurs.

[0007] SBR for lithium battery is a butadiene styrene latex emulsion, a water-based adhesive, which is generated by emulsion polymerization and copolymerization of styrene and butadiene monomers in water medium with the addition of emulsifiers and initiators, and has a solid content of about 50%. It has strong water resistance. However, when SBR is used as a binder to prepare a current collector carbon coating layer slurry, SBR is unstable in the slurry due to its poor affinity with conductive agents, and the phenomenon of blue floating occurs, which can cause uneven material on the coating roll, resulting in uneven stripes on the appearance of the carbon coating layer.

[0008] Due to the instability of SBR in the slurry in the prior art, the phenomenon of blue floating occurs, the carbon-coated current collector has poor water resistance, and stripes easily occur. Therefore, it is urgent to develop a conductive carbon material with high affinity with butadiene styrene latex emulsion to prepare a carbon-coated current collector with good water resistance and no stripes. SUMMARY

[0009] In view of the deficiencies of the prior art, the purpose of the present application is to provide a modified conductive carbon material, a preparation method and application thereof. The modified conductive carbon material is obtained by polymerization of methyl methacrylate, butyl acrylate and polymerizable silane coupling agent to obtain a terpolymer, and the surface of the conductive agent carbon material is modified. The terpolymer has a physical effect and chemical bonding on the conductive carbon material through the polar bond, so that SBR tends to be stable in the slurry, the generation of stripes in the carbon-coated current collector is reduced, and the water resistance is improved.

[0010] To achieve this purpose, the technical scheme adopted by the present application is as follows:

[0011] In a first aspect, the present application provides a modified conductive carbon material, raw materials for preparing the modified conductive carbon material include, in parts by weight: 60-80 parts of methyl methacrylate, 10-20 parts of butyl acrylate, 1-5 parts of a polymerizable silane coupling agent, 5-10 parts of a conductive carbon material, 0.1-0.2 parts of a first initiator, 0.1-0.3 parts of a second initiator, 1-10 parts of a first solvent, and 0.1-1 parts of a second solvent.

[0012] In the modified conductive carbon material provided by the present application, the methyl methacrylate, butyl acrylate, and polymerizable silane coupling agent react to form a macromolecular terpolymer; the macromolecular surface treatment agent methyl methacrylate (MMA)-butyl acrylate (BA)-polymerizable silane coupling agent terpolymer is used to modify the surface of the conductive carbon material, the terpolymer polar bond has a physical effect and chemical bonding on the conductive carbon material, the surface free energy of the carbon material powder is reduced, the agglomeration phenomenon is alleviated, the particle size is greatly reduced, the hydrophobicity is significantly weakened, the affinity with SBR is increased, the crosslinking degree with SBR is improved, and the SBR tends to be stable in the slurry.

[0013] Preferably, the weight parts of the methyl methacrylate are 60-80, for example, can be 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, and specific point values between the above-mentioned point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0014] Preferably, the weight parts of the butyl acrylate are 10-20, for example, can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, and specific point values between the above-mentioned point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0015] Preferably, the weight parts of the polymerizable silane coupling agent are 1-5, for example, can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, and specific point values between the above-mentioned point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0016] Preferably, the weight parts of the conductive carbon material are 5-10, for example, can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and specific point values between the above-mentioned point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0017] Preferably, the weight parts of the first initiator are 0.1-0.2, for example, can be 0.1 part, 0.15 part, 0.2 part, and specific point values between the above-mentioned point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0018] Preferably, the weight portion of the second initiator is 0.1-0.3 parts, for example, it can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0019] Preferably, the weight portion of the first solvent is 1-10 parts, for example, it can be 1 part, 3 parts, 5 parts, 7 parts, 9 parts, 10 parts, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0020] Preferably, the weight portion of the second solvent is 0.1-1 part, for example, it can be 0.1 part, 0.5 part, 1 part, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0021] Preferably, the polymerizable silane coupling agent includes any one or a combination of at least two of γ-methacryloxypropyltrimethoxysilane (eg, KH-570), vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(methoxyethoxy)silane, or aminopropyltriethoxysilane.

[0022] Preferably, the conductive carbon material includes any one of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers or graphene, or a combination of at least two of them.

[0023] Preferably, the first initiator comprises benzoyl peroxide.

[0024] Preferably, the second initiator comprises cumene peroxide.

[0025] Preferably, the first solvent comprises toluene.

[0026] Preferably, the first solvent is an aqueous solution of toluene.

[0027] Preferably, the concentration of toluene in the aqueous solution of toluene is 0.05-0.1 mg / L, for example, it can be 0.05 mg / L, 0.06 mg / L, 0.07 mg / L, 0.08 mg / L, 0.09 mg / L, 0.1 mg / L, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0028] Preferably, the second solvent comprises acetone.

[0029] The present invention uses a macromolecular surface treatment agent, methyl methacrylate (MMA)-butyl acrylate (BA)-silane coupling agent terpolymer, to perform surface modification on a conductive carbon material. The polar bonds of the terpolymer physically act and chemically bond to the conductive carbon material, thereby reducing the surface free energy of the carbon material powder, alleviating agglomeration, significantly reducing the particle size, and significantly weakening the hydrophobicity. By modifying the hydroxyl and carboxyl groups and double bond cross-linking reactions in SBR, the affinity with SBR is increased, the cross-linking degree with SBR is improved, and the SBR is stabilized in the slurry.

[0030] In a second aspect, the present invention provides a method for preparing the modified conductive carbon material as described in the first aspect, the preparation method comprising:

[0031] Methyl methacrylate, butyl acrylate, a silane coupling agent, a conductive carbon material, a first initiator, a second initiator, a first solvent, and a second solvent are mixed and reacted to obtain the modified conductive carbon material.

[0032] Preferably, the preparation method specifically includes: mixing methyl methacrylate, butyl acrylate, a silane coupling agent, and a first solvent, adding a first initiator, keeping warm for a first time, adding a second initiator, keeping warm for a second time, and cooling to obtain a ternary copolymer solution; mixing the ternary copolymer solution with a conductive carbon material and a second solvent, reacting to obtain the modified conductive carbon material.

[0033] Preferably, the temperature of the first insulation is 80-90°C, for example, it can be 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0034] Preferably, the first insulation time is 1-3h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0035] Preferably, the temperature of the second insulation is 110-120°C, for example, it can be 110°C, 112°C, 114°C, 116°C, 118°C, 120°C, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0036] Preferably, the second insulation time is 1-3h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0037] Preferably, the temperature of the reaction is 70-90℃, for example, it can be 70℃, 75℃, 80℃, 85℃, 90℃, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not list the specific point values included in the range.

[0038] Preferably, the time of the reaction is 2-4h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not list the specific point values included in the range.

[0039] Preferably, the reaction is followed by cooling and drying.

[0040] Preferably, the temperature of the drying is 40-60℃, for example, it can be 40℃, 45℃, 50℃, 55℃, 60℃, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not list the specific point values included in the range.

[0041] Preferably, the time of the drying is 10-15h, for example, it can be 10h, 11h, 12h, 13h, 14h, 15h, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not list the specific point values included in the range.

[0042] In a third aspect, the present application provides a water-resistant carbon-coated current collector, which comprises a foil and a conductive coating layer arranged on the surface of the foil; the conductive coating layer comprises the modified conductive carbon material and the binder as described in the first aspect.

[0043] Preferably, the conductive coating layer is formed after the modified conductive paste is coated and cured.

[0044] Preferably, the solid content of the modified conductive paste is 8-13.5%, and the pH of the modified conductive paste is 6-8.

[0045] Preferably, the material of the conductive coating layer comprises, by weight: 5-10 parts of the modified conductive carbon material, and 7-22 parts of the binder.

[0046] Preferably, the weight of the modified conductive carbon material is 5-10 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not list the specific point values included in the range.

[0047] Preferably, the weight proportion of the binder is 7-22 parts, for example, 7 parts, 10 parts, 15 parts, 20 parts, 22 parts, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0048] Preferably, the binder comprises styrene-butadiene rubber latex.

[0049] Preferably, the solid content of the styrene-butadiene rubber latex is 40-50%, for example, it can be 40%, 42%, 44%, 46%, 48%, 50%, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0050] Preferably, the viscosity of the adhesive is 5-500 mPa.s, for example, it can be 5 mPa.s, 50 mPa.s, 100 mPa.s, 150 mPa.s, 200 mPa.s, 250 mPa.s, 300 mPa.s, 350 mPa.s, 400 mPa.s, 450 mPa.s, 500 mPa.s, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0051] Preferably, the particle size of the binder is 20-200 nm, for example, it can be 20 nm, 50 nm, 100 nm, 150 nm, 200 nm, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0052] Preferably, the conductive coating material further comprises, by weight: 0.3-1 parts of a dispersant and 3-20 parts of a wetting agent.

[0053] Preferably, the weight portion of the dispersant is 0.3-1 part, for example, it can be 0.3 part, 0.5 part, 0.8 part, 1 part, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0054] Preferably, the weight portion of the wetting agent is 3-20 parts, for example, it can be 3 parts, 5 parts, 10 parts, 15 parts, 20 parts, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0055] Preferably, the dispersant comprises sodium carboxymethylcellulose and / or potassium carboxymethylcellulose.

[0056] Preferably, the wetting agent includes any one of isopropyl alcohol, propylene glycol, n-octanol, polyethylene glycol or polyoxyethylene ether, or a combination of at least two thereof.

[0057] Preferably, the foil material includes any one of aluminum foil, titanium foil or composite aluminum foil, or a combination of at least two of them.

[0058] Preferably, the raw materials for preparing the conductive coating include a solvent.

[0059] Preferably, the solvent comprises water.

[0060] In a fourth aspect, the present invention provides a method for preparing the water-resistant carbon-coated current collector as described in the third aspect, the preparation method comprising:

[0061] (1) mixing the modified conductive carbon material with a binder to obtain a modified conductive slurry;

[0062] (2) coating the modified conductive slurry obtained in step (1) on the surface of the foil and drying it to obtain the water-resistant carbon-coated current collector.

[0063] Preferably, the mixed materials in step (1) further include a dispersant, a wetting agent, and a solvent.

[0064] Preferably, the mixing in step (1) is carried out under stirring.

[0065] Preferably, the stirring rate is 10-60 rpm, for example, it can be 10 rpm, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0066] Preferably, the mixing temperature is 15-30°C, for example, it can be 15°C, 18°C, 20°C, 22°C, 26°C, 28°C, 30°C, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0067] Preferably, the mixing time is 10-60 min, for example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0068] Preferably, the coating comprises dispersing using a homogenizer bar.

[0069] As a preferred technical solution of the present invention, a homogenizer rod disperses the surface SBR of the slurry. This rod is typically a hollow rod made of aluminum alloy with continuous spiral protrusions on its surface. It has magnetic material and rubber spacers at both ends, allowing it to adhere to the plate roller without being tightly attached. The homogenizer rod floats on the surface of the slurry. As the plate roller rotates, it is attracted by the rod and rotates in the opposite direction. As it rotates, the ripples on the surface of the slurry move it, causing it to move, thus evenly dispersing the SBR on the surface and preventing bluish tint.

[0070] Preferably, the coating rate in step (2) is 30-150 m / min, for example, it can be 30 m / min, 40 m / min, 50 m / min, 80 m / min, 100 m / min, 120 m / min, 150 m / min, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0071] Preferably, the coating thickness in step (2) is ≤2 μm on a single side, for example, it can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0072] Preferably, the drying temperature in step (2) is 75-120°C, for example, it can be 75°C, 80°C, 90°C, 100°C, 110°C, 120°C, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0073] Preferably, the drying time in step (2) is 10-60 min, for example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0074] A high oven temperature or a long oven time helps to increase the crosslinking degree of the styrene-butadiene rubber latex and improve the adhesion and water resistance of the carbon-coated current collector.

[0075] The coating of conductive carbon materials with silane coupling agent can interact with both the hydroxyl groups in inorganic substances and the long molecular chains in organic polymers, coupling the two materials with different properties. It can not only increase the cross-linking degree of styrene-butadiene rubber latex, enhance water resistance, strengthen the adhesion between metal foil and conductive materials, but also enhance the wettability of the slurry on the foil.

[0076] Preferably, the method for preparing the water-resistant carbon-coated current collector specifically includes:

[0077] (1) preparing a dispersant aqueous solution, adding the dispersant into the remaining solvent water until it is completely dissolved into a transparent solution;

[0078] (2) adding the modified conductive carbon material into the dispersant aqueous solution in the previous step in multiple times, to obtain a conductive carbon aqueous solution;

[0079] (3) slowly adding the wetting agent into the conductive carbon aqueous solution in the previous step, to obtain a mixed solution;

[0080] (4) homogenizing or sand milling the mixed solution in the previous step, to obtain a dispersed mixed solution;

[0081] (5) adding the binder into the dispersed mixed solution in the previous step, and then adding the wetting agent after low-speed stirring and dispersion, to obtain a mixed slurry;

[0082] (6) vacuumizing the mixed slurry in the previous step, to obtain a modified conductive slurry;

[0083] (7) coating the modified conductive slurry in the previous step on the foil by a coating machine, drying and then winding to obtain a water-resistant carbon-coated current collector.

[0084] The stirring and dispersion speed of the dispersant aqueous solution in the above step (1) is not fixedly required, and the higher the stirring speed, the faster the dissolution time, and the lower the stirring speed, the slower the dissolution time.

[0085] The D50 of the dispersed mixed solution in the above step (4) is less than 1.2 μm, and the D90 is less than 5 μm.

[0086] In the above step (7), the modified conductive slurry is placed in a coating machine tank, the coating machine tank is provided with a slurry uniformizing rod, the length of the slurry uniformizing rod exceeds the length of the plate roller by 2-4 cm; the slurry uniformizing rod is used to disperse and reduce the blue drift problem caused by SBR in the modified conductive slurry, and to ensure the consistency of the slurry on the screen roller. The slurry uniformizing rod is a hollow rod made of aluminum alloy, and has continuous spiral protrusions on the surface, and magnetic materials and rubber separators at both ends, which can be adsorbed on the plate roller but not tightly attached to the plate roller. The modified conductive slurry is coated in the coating machine, the foil is first subjected to corona and / or preheating oven to remove the oil on the surface of the foil and improve the daoyin value of the foil, and the corona power is not less than 6 KW.

[0087] Compared with the prior art, the present application has the following beneficial effects:

[0088] The modified conductive carbon material provided by the present invention uses a macromolecular surface treatment agent, methyl methacrylate-butyl acrylate-polymerizable silane coupling agent terpolymer, to perform surface modification on the conductive carbon material. The polar bonds of the terpolymer physically act and chemically bond to the conductive carbon material to form hydrogen bonds, thereby reducing the surface free energy of the carbon material powder, alleviating agglomeration, greatly reducing the particle size, and significantly weakening the hydrophobicity. Through the cross-linking reaction of hydroxyl groups, carboxyl groups and double bonds in SBR, the affinity with SBR is increased, the cross-linking degree with SBR is improved, and the SBR is stabilized in the slurry. The carbon-coated current collector prepared with the modified conductive carbon material improves the problem of coating film surface stripes caused by the instability of styrene-butadiene rubber latex in the slurry, and at the same time enhances water resistance, with a water-resistant wipe resistance of 51-88 times. DETAILED DESCRIPTION

[0089] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0090] The experimental materials used in the examples and comparative examples of the present invention are as follows:

[0091] (1) Styrene-butadiene latex, brand 350HC, manufactured by SUNROSE, Japan;

[0092] (2) Conductive carbon material SPLi, brand SUPERP LI, manufacturer IMERYS;

[0093] (3) Conductive graphite KS6, brand TIMREX KS 6, manufacturer IMERYS;

[0094] (4) Carbon nanotubes, brand XFM04, manufactured by Xianfeng Nano;

[0095] Example 1

[0096] This embodiment provides a modified conductive carbon material and a preparation method thereof. The raw materials for preparing the modified conductive carbon material include, by mass: 70g methyl methacrylate, 20g butyl acrylate, 4g polymerizable silane coupling agent KH-570, 10g conductive carbon material SPLi, 0.1g first initiator benzoyl peroxide, 0.2g second initiator isopropyl benzene peroxide, 6g of a first solvent toluene aqueous solution with a concentration of 0.5mg / L, and 0.1g second solvent acetone;

[0097] The preparation method of the modified conductive carbon material is specifically as follows:

[0098] (1) According to the above formula, methyl methacrylate (MMA), butyl acrylate (BA), polymerizable silane coupling agent (KH-570) and toluene were added in sequence to a three-necked flask equipped with a stirrer, a condenser and a nitrogen connecting tube. After sufficient stirring, the temperature was raised to 80°C. The first initiator, benzoyl peroxide, was gradually added dropwise. The temperature was kept at 85°C for 2 hours. The second initiator, cumyl peroxide, was then added. The temperature was raised to 115°C and kept for 2 hours. After cooling, a terpolymer solution was obtained.

[0099] The conductive carbon material SPLi was placed into the ternary copolymer solution in the above three-necked flask, acetone was added, ultrasonic dispersion was performed for 15 minutes, and then high-speed stirring was carried out at 80°C for 3 hours under nitrogen protection. After cooling, it was placed in a 50°C oven under vacuum drying for 12 hours to obtain the modified conductive carbon material SPLi.

[0100] This embodiment also provides a water-resistant carbon-coated current collector, which includes a foil (aluminum foil) and a conductive coating provided on the surface of the foil, wherein the conductive coating includes the aforementioned modified conductive carbon material. The specific preparation method is as follows:

[0101] (1) Add 0.5 g of dispersant sodium carboxymethyl cellulose to the solvent water and stir until it is completely dissolved to form a transparent solution;

[0102] (2) 5 g of the modified conductive material SP-Li was added to the dispersant aqueous solution in step (1) in two equal portions, with a stirring speed of 60 rpm and a dispersion speed of 4000 rpm in a dual planetary mixer at a temperature of 25 ± 5 ° C. Each time for 15 min to obtain a conductive carbon aqueous solution;

[0103] (3) Slowly add 15 g of isopropyl alcohol as a wetting agent to the conductive carbon aqueous solution in step (2) at a stirring speed of 60 rpm, a dispersion speed of 4000 rpm, a temperature of 25 ± 5 ° C, and a time of 30 min to obtain a mixed solution;

[0104] (4) The mixed solution in step (3) was subjected to a homogenizer to particle size treatment, and after treatment, D50 = 0.886 μm, D90 = 4.34 μm, to obtain a dispersed mixed solution;

[0105] (5) 7 g of a binder styrene-butadiene rubber latex (solid content 45%, viscosity <100 mPa.s, particle size D90 160 nm) was added to the dispersed mixed solution in step (4) at a stirring speed of 30 rpm and a dispersion speed of 500 rpm in a dual planetary mixer at a temperature of 25 ± 5 °C for 15 min to obtain a mixed slurry;

[0106] (6) The mixed slurry in step (5) was vacuumed, and the reverse stirring speed of the double planetary mixer was 10 rpm, the vacuum degree was <-0.07 KPa, the temperature was 25±5°C, and the time was 30 min to obtain a modified conductive slurry (solid content was 8.5%, and the slurry pH was 7.1).

[0107] (7) The modified conductive paste in step (6) is coated on a double-sided smooth aluminum foil by a coating machine. The aluminum foil is pretreated with a corona machine. The coating speed is 50 m / min, the coating thickness on one side is 1±0.2 μm, and the oven temperature is 100° C. for 15 min. The water-resistant carbon-coated current collector is rolled up.

[0108] Example 2

[0109] This embodiment provides a modified conductive carbon material and a preparation method thereof. The raw materials for preparing the modified conductive carbon material include, by mass: 70g of methyl methacrylate, 20g of butyl acrylate, 4g of a polymerizable silane coupling agent KH-570, 10g of a conductive carbon material (the mass ratio of SP-Li to conductive graphite SK6 is 8:2), 0.1g of a first initiator benzoyl peroxide, 0.2g of a second initiator isopropyl benzene peroxide, 6g of an aqueous solution of a first solvent toluene with a concentration of 0.5mg / L, and 0.1g of a second solvent acetone;

[0110] The preparation method of the modified conductive carbon material is specifically as follows:

[0111] (1) According to the above formula, methyl methacrylate (MMA), butyl acrylate (BA), polymerizable silane coupling agent (KH-570) and toluene were added in sequence to a three-necked flask equipped with a stirrer, a condenser and a nitrogen connecting tube. After sufficient stirring, the temperature was raised to 80°C. The first initiator, benzoyl peroxide, was gradually added dropwise. The temperature was kept at 85°C for 2 hours. The second initiator, cumyl peroxide, was then added. The temperature was raised to 115°C and kept for 2 hours. After cooling, a terpolymer solution was obtained.

[0112] The conductive carbon material (SP-Li and conductive graphite SK6 mass ratio of 8:2) was placed in the ternary copolymer solution in the above three-necked flask, acetone was added, ultrasonic dispersion was performed for 15 minutes, and then high-speed stirring was carried out at 80°C under nitrogen protection for 3 hours. After cooling, it was placed in a 50°C oven under vacuum drying for 12 hours to obtain a modified conductive carbon material.

[0113] This embodiment also provides a water-resistant carbon-coated current collector, which includes a foil (aluminum foil) and a conductive coating provided on the surface of the foil, wherein the conductive coating includes the aforementioned modified conductive carbon material. The specific preparation method is as follows:

[0114] (1) Add 0.5 g of dispersant sodium carboxymethyl cellulose to the solvent water and stir until it is completely dissolved to form a transparent solution;

[0115] (2) 5 g of the modified conductive material was added to the dispersant aqueous solution in step (1) in two equal portions, with a stirring speed of 60 rpm and a dispersion speed of 4000 rpm in a dual planetary mixer at a temperature of 25 ± 5 ° C. Each time was 15 min to obtain a conductive carbon aqueous solution;

[0116] (3) Slowly add 15 g of isopropyl alcohol as a wetting agent to the conductive carbon aqueous solution in step (2) at a stirring speed of 60 rpm, a dispersion speed of 4000 rpm, a temperature of 25 ± 5 ° C, and a time of 30 min to obtain a mixed solution;

[0117] (4) The mixed solution in step (3) was subjected to a homogenizer to particle size treatment, and after treatment, D50 = 0.912 μm, D90 = 4.12 μm, to obtain a dispersed mixed solution;

[0118] (5) 11 g of a binder styrene-butadiene rubber latex (solid content 45%, viscosity <100 mPa.s, particle size D90 160 nm) was added to the dispersed mixed solution in step (4) at a stirring speed of 30 rpm and a dispersion speed of 800 rpm in a dual planetary mixer at a temperature of 25 ± 5 °C for 20 min to obtain a mixed slurry;

[0119] (6) The mixed slurry in step (5) was vacuumed, and the reverse stirring speed of the double planetary mixer was 10 rpm, the vacuum degree was <-0.07 KPa, the temperature was 25±5°C, and the time was 30 min to obtain a modified conductive slurry (solid content of 10.05%, slurry pH of 6.9).

[0120] (7) The modified conductive paste in step (6) is coated on a double-sided smooth aluminum foil by a coating machine. The aluminum foil is pretreated with a corona machine. The coating speed is 80m / min, the coating thickness on one side is 1±0.2um, and the oven temperature is 120℃ for 10min. The water-resistant carbon-coated current collector is rolled up.

[0121] Example 3

[0122] This embodiment provides a modified conductive carbon material and a preparation method thereof. The raw materials for preparing the modified conductive carbon material include, by mass: 80g of methyl methacrylate, 10g of butyl acrylate, 5g of a polymerizable silane coupling agent KH-570, 10g of a conductive carbon material (the mass ratio of SP-Li, conductive graphite SK6, and carbon nanotubes is 8:1.9:0.1), 0.2g of a first initiator, benzoyl peroxide, 0.2g of a second initiator, isopropyl benzene peroxide, 6g of an aqueous solution of a first solvent, toluene, with a concentration of 0.5mg / L, and 0.1g of a second solvent, acetone;

[0123] The preparation method of the modified conductive carbon material is specifically as follows:

[0124] (1) According to the formula amount, methyl methacrylate (MMA), butyl acrylate (BA), a polymerizable silane coupling agent (KH-570) and toluene were sequentially added into a three-necked flask with a stirrer, a condenser and a nitrogen connection pipe, and after being fully stirred, the temperature was raised to 80°C, the first initiator benzoyl peroxide was gradually added dropwise, and the temperature was kept at 85°C for 2 h, then the second initiator dicumyl peroxide was added, and the temperature was raised to 115°C and kept for 2 h, and after cooling, a terpolymer solution was obtained.

[0125] The conductive carbon material (SP-Li and conductive graphite SK6 and carbon nanotube mass ratio 8:1.9:0.1) was placed into the terpolymer solution in the three-necked flask, and acetone was added, and then ultrasonic dispersion was performed for 15 min, and then high-speed stirring was performed under nitrogen protection at 80°C for 3 h, and then the mixture was taken out, cooled and placed in a 50°C oven for vacuum drying for 12 h, to obtain a modified conductive carbon material.

[0126] The embodiment also provides a water-resistant carbon-coated current collector, which comprises a foil (aluminum foil) and a conductive coating layer arranged on the surface of the foil, and the conductive coating layer comprises the aforementioned modified conductive carbon material, and the specific preparation method is as follows:

[0127] (1) 0.3 g of a dispersant carboxymethyl cellulose sodium was added to a solvent water, and stirred until completely dissolved into a transparent solution;

[0128] (2) The aforementioned 10 g of modified conductive material was sequentially added into the dispersant aqueous solution in step (1) in two equal portions, the stirring speed of the double-planetary stirrer was 60 rpm, the dispersion speed was 4000 rpm, the temperature was 25±5°C, and the time was 15 min each time, to obtain a conductive carbon aqueous solution;

[0129] (3) 10 g of a wetting agent isopropyl alcohol was slowly added into the conductive carbon aqueous solution in step (2), the stirring speed of the double-planetary stirrer was 60 rpm, the dispersion speed was 4000 rpm, the temperature was 25±5°C, and the time was 30 min, to obtain a mixed solution;

[0130] (4) The mixed solution in step (3) was subjected to particle size treatment by a homogenizer, and after the treatment, D50=1.193 μm and D90=4.57 μm, to obtain a dispersed mixed solution;

[0131] (5) 7 g of a binder styrene-butadiene latex (solid content 45%, viscosity <200 mpa.s, particle size D90 145 nm) was added into the dispersed mixed solution in step (4), the stirring speed of the double-planetary stirrer was 30 rpm, the dispersion speed was 800 rpm, the temperature was 25±5°C, and the time was 20 min, to obtain a mixed slurry;

[0132] (6) The mixed slurry in step (5) was vacuumed, and the reverse stirring speed of the double planetary mixer was 10 rpm, the vacuum degree was <-0.07 KPa, the temperature was 25±5°C, and the time was 30 min to obtain a modified conductive slurry (solid content was 13.45%, and the slurry pH was 7.3).

[0133] (7) The modified conductive paste in step (6) is coated on a double-sided smooth aluminum foil by a coating machine. The aluminum foil is pre-treated with a corona machine. The coating speed is 40m / min, the coating thickness on one side is 2±0.2um, and the oven temperature is 120℃ for 20min. The water-resistant carbon-coated current collector is rolled up.

[0134] Example 4

[0135] This embodiment provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that the first insulation temperature is 80°C and the time is 3 hours; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0136] This embodiment also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this embodiment is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0137] Example 5

[0138] This embodiment provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that the second insulation temperature is 120 degrees Celsius and the time is 1 hour; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0139] This embodiment also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this embodiment is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0140] Example 6

[0141] This embodiment provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that the reaction temperature is 90° C. and the reaction time is 2 hours; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0142] This embodiment also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this embodiment is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0143] Example 7

[0144] This embodiment provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that the drying temperature is 60° C. and the drying time is 10 hours; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0145] This embodiment also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this embodiment is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0146] Comparative Example 1

[0147] This comparative example provides a carbon-coated current collector, which differs from Example 1 only in that the conductive carbon material is unmodified SPLi; the types, amounts and preparation methods of other components are the same as those in Example 1.

[0148] Comparative Example 2

[0149] This comparative example provides a carbon-coated current collector, which differs from Example 2 only in that the conductive carbon material is unmodified SP-Li and conductive graphite SK6, wherein the mass ratio of SP-Li to conductive graphite SK6 is 8:2; the types, amounts and preparation methods of other components are the same as those in Example 2.

[0150] Comparative Example 3

[0151] This comparative example provides a carbon-coated current collector, which differs from Example 3 only in that the conductive carbon material is unmodified SP-Li, conductive graphite SK6 and carbon nanotubes, wherein the mass ratio of SP-Li to conductive graphite SK6 and carbon nanotubes is 8:1.9:0.1; the types, amounts and preparation methods of other components are the same as those in Example 3.

[0152] Comparative Example 4

[0153] This comparative example provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that butyl acrylate is not added; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0154] This comparative example also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this comparative example is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0155] Comparative Example 5

[0156] This comparative example provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that methyl methacrylate is not added; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0157] This comparative example also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this comparative example is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0158] Comparative Example 6

[0159] This comparative example provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that no polymerizable silane coupling agent is added; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0160] This comparative example also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this comparative example is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0161] Comparative Example 7

[0162] This comparative example provides a modified conductive carbon material and a preparation method thereof. The preparation method differs from that of Example 1 only in that the amount of polymerizable silane coupling agent KH-570 used is 20 g; the types, amounts and preparation methods of other components are the same as those of Example 1.

[0163] This comparative example also provides a water-resistant carbon-coated current collector, which differs from the water-resistant carbon-coated current collector in Example 1 only in that the modified conductive carbon material provided in this comparative example is used in the conductive coating; the types, amounts and preparation methods of its components are the same as those in Example 1.

[0164] The performance of the carbon-coated current collectors obtained in Examples 1-7 and Comparative Examples 1-7 was tested using the following method:

[0165] (1) Surface resistance (place a 10 cm*10 cm sample flat and test it with a four-probe resistance tester);

[0166] (2) Peel strength (use 3M double-sided tape to adhere the foil to the surface of the steel plate, adhere 3M610 tape to the other side, fix the steel plate and the other end of the 3M610 tape, and perform the peel test at a speed of 50 mm / min);

[0167] (3) Water-resistant wipe (fix the carbon-coated foil on the table, and place the 25g weight + 55g adjustment rod (total 80g)

[0168] Press on a cotton swab soaked in pure water, apply force F to pull the weight and the adjustment rod back and forth to make the cotton swab wipe the carbon foil coating surface, observe whether the coating changes color and falls off, and record the number of wipes);

[0169] (4) Hydrolysis resistance after immersion for 24 h (the carbon-coated foil was completely immersed in pure water and the shedding of the carbon coating was observed after 24 h);

[0170] (5) Stripes: Observe with the eyes;

[0171] The various properties of the carbon-coated current collectors obtained in Examples 1-7 and Comparative Examples 1-7 were tested according to the above-mentioned performance testing method. The test results are shown in Table 1.

[0172] Table 1

[0173]

[0174]

[0175] From the data in Table 1, it can be seen that Examples 1-7 are prepared by preparing slurry with modified conductive material and using ink stick to assist in coating the slurry. Compared with Comparative Examples 1-3, the water wiping resistance is significantly improved, and the water wiping resistance can reach 51-88 times, and there is no streak on the film surface. At the same time, the surface resistance and peeling force are basically the same; compared with Example 1, Comparative Example 4 lacks butyl acrylate for softening, and the coating prepared by the modified conductive carbon material becomes brittle after drying. Although there is no streak, the peeling force is significantly reduced; for Example 1, Comparative Example 5 , the lack of methyl methacrylate will cause the modified conductive agent to agglomerate, the viscosity to increase, resulting in a significant increase in coating resistance and obvious coating stripes; for Example 1 and Comparative Example 6, the lack of a polymerizable silane coupling agent will cause the conductive agent to be weakly modified, the binding with the styrene-butadiene rubber latex to be weak, and the coating stripes to be obvious; for Example 1 and Comparative Example 7, excessive addition of a polymerizable silane coupling agent will cause the conductive agent to agglomerate, making it difficult to disperse, and the binding with the styrene-butadiene rubber latex to be weak, resulting in a decrease in the coating peeling force, a decrease in the number of water-resistant wiping times, and obvious stripes.

[0176] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate a modified conductive carbon material, its preparation method, and its application. However, the present invention is not limited to the above-mentioned embodiments, which does not mean that the present invention must rely on the above-mentioned embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for various raw materials in the product of the present invention, addition of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A modified conductive carbon material, characterized in that: The raw materials for preparing the modified conductive carbon material are, in parts by weight, 60-80 parts of methyl methacrylate, 10-20 parts of butyl acrylate, 1-5 parts of a polymerizable silane coupling agent, 5-10 parts of a conductive carbon material, 0.1-0.2 parts of a first initiator, 0.1-0.3 parts of a second initiator, 1-10 parts of a first solvent, and 0.1-1 parts of a second solvent. The conductive carbon material is composed of any one or a combination of at least two of conductive carbon black, conductive graphite, carbon nanotubes, carbon nanofibers or graphene; The modified conductive carbon material is prepared by the following method, which comprises the following steps: Methyl methacrylate, butyl acrylate, a polymerizable silane coupling agent, and a first solvent are mixed, a first initiator is added, and the mixture is kept warm for the first time. A second initiator is added, and the mixture is kept warm for the second time. After cooling, a ternary copolymer solution is obtained; the ternary copolymer solution is mixed with a conductive carbon material and a second solvent, and the mixture is reacted to obtain the modified conductive carbon material.

2. The modified conductive carbon material according to claim 1, characterized in that The polymerizable silane coupling agent includes any one of γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane or vinyltri(methoxyethoxy)silane, or a combination of at least two thereof.

3. The modified conductive carbon material according to claim 1, characterized in that The first initiator includes benzoyl peroxide.

4. The modified conductive carbon material according to claim 1, characterized in that The second initiator includes cumene peroxide.

5. The modified conductive carbon material according to claim 1, characterized in that The first solvent includes toluene.

6. The modified conductive carbon material according to claim 1, characterized in that The first solvent is an aqueous solution of toluene.

7. The modified conductive carbon material according to claim 6, characterized in that The concentration of toluene in the toluene aqueous solution is 0.5-1 mg / L.

8. The modified conductive carbon material according to claim 1, characterized in that The second solvent includes acetone.

9. A method for preparing the modified conductive carbon material according to any one of claims 1 to 8, characterized in that: The preparation method specifically includes: mixing methyl methacrylate, butyl acrylate, a polymerizable silane coupling agent, and a first solvent, adding a first initiator, keeping warm for a first time, adding a second initiator, keeping warm for a second time, and cooling to obtain a ternary copolymer solution; mixing the ternary copolymer solution with a conductive carbon material and a second solvent, reacting to obtain the modified conductive carbon material.

10. The preparation method according to claim 9, characterized in that The temperature of the first insulation is 80-90°C.

11. The preparation method according to claim 9, characterized in that The first insulation time is 1-3 hours.

12. The preparation method according to claim 9, characterized in that The temperature of the second insulation is 110-120°C.

13. The preparation method according to claim 9, characterized in that The second insulation time is 1-3h.

14. The preparation method according to claim 9, characterized in that The reaction temperature is 70-90°C.

15. The preparation method according to claim 9, characterized in that The reaction time is 2-4 hours.

16. The preparation method according to claim 9, characterized in that The reaction is followed by cooling and drying.

17. The preparation method according to claim 16, characterized in that The drying temperature is 40-60°C.

18. The preparation method according to claim 16, characterized in that The drying time is 10-15 hours.

19. A water-resistant carbon-coated current collector, characterized in that: The water-resistant carbon-coated current collector comprises a foil and a conductive coating disposed on the surface of the foil, wherein the conductive coating comprises a combination of the modified conductive carbon material according to any one of claims 1 to 8 and a binder.

20. The water-resistant carbon-coated current collector according to claim 19, characterized in that: The materials of the conductive coating include, by weight: 5-10 parts of the modified conductive carbon material and 7-22 parts of a binder.

21. The water-resistant carbon-coated current collector according to claim 19, characterized in that: The viscosity of the adhesive is 5-500 mPa.s.

22. The water-resistant carbon-coated current collector according to claim 19, wherein: The particle size of the binder is 20-200 nm.

23. The water-resistant carbon-coated current collector according to claim 20, characterized in that: The conductive coating material further comprises, by weight, 0.3-1 parts of a dispersant and 3-20 parts of a wetting agent.

24. The water-resistant carbon-coated current collector according to claim 23, characterized in that: The dispersant includes sodium carboxymethyl cellulose and / or potassium carboxymethyl cellulose.

25. The water-resistant carbon-coated current collector according to claim 23, characterized in that: The wetting agent includes any one of isopropyl alcohol, propylene glycol, n-octanol, polyethylene glycol or polyoxyethylene ether, or a combination of at least two thereof.

26. The water-resistant carbon-coated current collector according to claim 19, characterized in that: The foil material includes any one of aluminum foil, titanium foil or composite aluminum foil, or a combination of at least two of them.

27. A method for preparing a water-resistant carbon-coated current collector according to any one of claims 19 to 26, characterized in that: The preparation method comprises: (1) mixing the modified conductive carbon material with a binder to obtain a modified conductive slurry; (2) coating the modified conductive slurry obtained in step (1) on the surface of the foil and drying it to obtain the water-resistant carbon-coated current collector.

28. The preparation method according to claim 27, characterized in that The mixed materials in step (1) also include a dispersant, a wetting agent, and a solvent.

29. The preparation method according to claim 27, characterized in that The mixing in step (1) is carried out under stirring.

30. The preparation method according to claim 29, characterized in that The stirring speed is 10-5000 rpm.

31. The preparation method according to claim 27, characterized in that The mixing temperature is 15-30°C.

32. The preparation method according to claim 27, characterized in that The mixing time is 10-60 minutes.

33. The preparation method according to claim 27, characterized in that The coating includes dispersing using a homogenizer bar.

34. The preparation method according to claim 27, characterized in that The coating rate in step (2) is 30-150 m / min.

35. The preparation method according to claim 27, characterized in that The coating thickness in step (2) is ≤2 μm on one side.

36. The preparation method according to claim 27, characterized in that The drying temperature in step (2) is 75-120°C.

37. The preparation method according to claim 27, characterized in that The drying time in step (2) is 10 min to 60 min.

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