High-adhesion and water-resistant carbon-coated current collector and preparation method and application thereof

Abstract

The invention relates to the field of batteries, in particular to a high-adhesion and water-resistant carbon-coated current collector and a preparation method and application thereof. The carbon-coated foil comprises a foil body and a carbon-coated layer attached to the surface of the foil body, conductive slurry of the carbon coating layer is composed of a conductive agent, a dispersing agent and a modified binder according to a specific ratio, and the modified binder is prepared through specific components and processes and has the characteristic of low viscosity. By optimizing a coating material formula and a preparation process, the adhesive force and the water resistance of the carbon-coated current collector are remarkably improved, so that the overall stability of an electrochemical energy storage device is improved, and the service life of the electrochemical energy storage device is prolonged.

Description

Technical Field

[0001] The present application relates to the field of batteries, and more specifically, to a carbon-coated current collector with high adhesion and water resistance, its preparation method and application. Background Art

[0002] In modern society, lithium batteries and sodium batteries have become an indispensable energy storage method in mobile electronic devices, electric vehicles and large-scale energy storage systems due to their high energy density, long life and environmental friendliness. In new batteries such as lithium-ion batteries and sodium-ion batteries, the current collector is an important main material.

[0003] Existing conductive layer coating technologies usually have problems such as poor adhesion between the coating and the electrode sheet and easy powder falling, which will cause the conductive layer to gradually fail during the use of the battery, thus affecting the performance of the battery. For this reason, CN108258249A discloses a current collector coating, slurry and its preparation method, battery electrode sheet and lithium-ion battery. The current collector coating includes a conductive agent, a conductive heat-insulating material and a binder. The lithium-ion battery made of the current collector coating provided by this technical solution not only has high safety, but also has good electrochemical properties, but the adhesion of this current collector coating is insufficient.

[0004] At the same time, in recent years, under the requirements of national environmental protection policies, the positive electrode active material coating in lithium-ion batteries of secondary batteries has gradually developed from the original oily system to the aqueous system; for secondary battery sodium-ion batteries, the positive and negative electrode active material coatings are both aqueous systems, and higher requirements are placed on the water resistance and surface anti-corrosion of the current collector coating.

[0005] Based on this, there is an urgent need to develop a carbon-coated current collector that can simultaneously have high adhesion and high water resistance. Summary of the Invention

[0006] In order to solve the above technical problems, the present application provides a carbon-coated current collector with high adhesion and water resistance, its preparation method and application.

[0007] The present application adopts the following technical solutions: In the first aspect, the present application provides a carbon-coated current collector with high adhesion and water resistance, which includes a foil body and a carbon-coated layer attached to the surface of the foil body; The conductive paste of the carbon-coated layer includes a conductive agent, a dispersant and a modified binder, and the viscosity of the conductive paste is less than 150 mPa·s; The modified binder includes, by weight: 10-20 parts of isobornyl methacrylate, 20-40 parts of acrylonitrile, 15-30 parts of ethyl methacrylate, 25-35 parts of n-butyl acrylate, 10-20 parts of 2-hydroxyethyl methacrylate, and 35-45 parts of initiator.

[0008] By adopting the above technical solution, the coated carbon current collector can significantly improve the bonding strength between the coated carbon layer and the foil body by using the modified binder, effectively prevent the coating from peeling off, and ensure the stability during long-term use. At the same time, the specific component ratio of the modified binder and the low-viscosity conductive paste endow the coating with excellent water resistance, meeting the requirements of the current collector for the aqueous system battery and improving the overall performance and reliability of the battery.

[0009] Furthermore, the preparation method of the above-mentioned modified binder includes: By weight, ethyl methacrylate, n-butyl acrylate, and isobornyl methacrylate are dispersed in an organic solvent, and an initiator is added under stirring conditions for pre-polymerization reaction; Subsequently, acrylonitrile and 2-hydroxyethyl methacrylate are added for cross-linking reaction, and the modified binder is obtained after cooling.

[0010] Among them, in the formula of the modified binder, acrylonitrile, ethyl methacrylate, and isobornyl methacrylate can improve the hardness of the material. The -CN group of acrylonitrile has the function of improving water resistance and acts as a branched chain in the polymer to enhance the corrosion resistance. Ethyl methacrylate has cross-linking characteristics. The -COOCH3 group can greatly improve the adhesion, and the -OH group is an active group that can undergo esterification and cross-linking reactions. Introducing it into this binder is mainly to increase the cross-linking sites. n-Butyl acrylate is a soft monomer, and its introduction helps to improve the flexibility of the binder molecular chain, maintain the integrity of the overall chain segment during the cross-linking process, and facilitate rapid film formation and wetting on the foil after coating. After polymerizing and cross-linking the above materials, a highly cross-linked 3D network structure is formed, which has high bonding strength and water resistance. During the homogenization process with carbon materials, the oxygen-containing functional groups (such as hydroxyl groups, carbonyl groups, etc.) in the carbon materials further react with the binder through hydrolysis to form hydrogen bonds, further enhancing the adhesion to the foil surface.

[0011] Furthermore, when adding the initiator, the temperature of the reaction solution is controlled at 70 - 95 °C, and the time of the pre-polymerization reaction is 2 - 3 h.

[0012] By adopting the above technical solution, controlling the temperature of the reaction solution within the range of 70 - 95 °C and the pre-polymerization reaction time within 2 - 3 hours can effectively promote the full activation and participation of the initiator in the reaction, thereby improving the cross-linking degree and uniformity of the modified binder. The optimization treatment under this condition significantly enhances the adhesion between the coated carbon layer and the foil body and improves the water resistance of the final product.

[0013] Furthermore, the reaction temperature of the above cross-linking reaction is 80 - 100 °C, and the reaction time is 1 - 2 h.

[0014] By adopting the above technical solution, controlling the reaction temperature of the crosslinking reaction within the range of 80 - 100 °C and setting the reaction time to 1 - 2 hours can effectively promote the full progress of the crosslinking reaction between acrylonitrile and hydroxyethyl methacrylate. The reaction under this condition enables the formed modified binder to form a more compact and stable three-dimensional network structure, thereby further enhancing the bonding strength between the carbon-coated layer and the foil body and improving the water resistance and mechanical stability of the coating.

[0015] Preferably, the initiator includes azobisisobutyronitrile.

[0016] Furthermore, in terms of weight percentage of the above conductive paste, the conductive agent is 5 - 10 wt%, the dispersant is 0.1 - 3 wt%, and the modified binder is 8 - 15 wt%.

[0017] By adopting the above technical solution, the content of the conductive agent in the conductive paste is 5 - 10 wt%, ensuring that the coating has good conductive performance; the content of the dispersant is 0.1 - 3 wt%, which helps to improve the uniform distribution of the conductive agent in the solvent and enhance the stability and consistency of the coating; the content of the modified binder is 8 - 15 wt%, effectively improving the adhesion between the carbon-coated layer and the foil body and at the same time improving the water resistance of the coating. The optimization of the proportion of these components enables the finally prepared high-adhesion and water-resistant carbon-coated current collector to not only have excellent conductive performance but also effectively prevent water penetration and extend the service life of the battery.

[0018] Preferably, the conductive agent includes one or more of artificial graphite, modified graphite, natural graphite, hard carbon, soft carbon, and silicon-carbon composite.

[0019] Preferably, the dispersant includes any one or at least two combinations of carboxymethyl cellulose and its lithium salt or sodium salt, polyvinylpyrrolidone, polyalkylene oxide unsaturated monomer, DIS-730A, isopropanol solution, or SDS-720.

[0020] In a second aspect, the present application provides a preparation method of the above high-adhesion and water-resistant carbon-coated current collector, which includes: Disperse the dispersant and the conductive agent in a solvent to obtain a conductive carbon solution; Add the modified binder to the conductive carbon solution under stirring, and obtain a conductive paste after dispersion and mixing; Coat the conductive paste on the surface of the foil body, and form a carbon-coated layer after drying, and the density of the carbon-coated layer is less than 0.7 g / m 2 .

[0021] By adopting the above technical solution, the conductive agent and the dispersant are first fully dispersed in the solvent to form a uniform and stable conductive carbon solution, ensuring good fluidity and uniformity during the subsequent coating process. The addition of the modified binder further improves the adhesion between the coating and the foil body, effectively preventing the coating from peeling off. The finally formed carbon-coated layer has a low density (less than 0.7g / m 2 ), which not only ensures the lightweight of the current collector but also improves its water resistance and mechanical strength, making it suitable for various harsh working environments.

[0022] Furthermore, during the preparation of the conductive paste, it also includes: Adding the modified binder to the conductive carbon solution under stirring conditions to obtain a mixed solution, and performing sanding treatment and demagnetization treatment on the mixed solution to obtain the conductive paste.

[0023] With this technical solution, by introducing the sanding treatment and demagnetization treatment steps, the quality of the conductive paste is further improved. The sanding treatment can make the conductive agent particles finer, reduce the presence of large particles, thereby improving the flatness and uniformity of the coating. This not only helps to improve the conductive performance of the coating but also reduces the stress concentration points inside the coating, improving the mechanical strength of the coating. The demagnetization treatment removes potential metal impurities, ensuring the purity of the coating and avoiding problems such as short circuits caused by impurities.

[0024] Furthermore, the sanding treatment includes: performing cyclic grinding on the mixed solution, with the grinding temperature being 15 - 25°C and the grinding time being 30 - 60 min.

[0025] By adopting the above technical solution, by performing cyclic grinding on the mixed solution, controlling the grinding temperature to be 15 - 25°C and the grinding time to be 30 - 60 min, the uniformity and stability of the conductive paste can be effectively improved, further enhancing the adhesion between the carbon-coated layer and the foil body, while ensuring the water resistance of the coating, enabling the prepared high-adhesion and water-resistant carbon-coated current collector to exhibit excellent comprehensive performance in practical applications.

[0026] Furthermore, after coating the conductive paste on the surface of the foil body, it is dried in a constant-speed increasing temperature manner within the range of 60 - 140°C.

[0027] Adopting this drying method, the drying rate of the conductive paste during the coating process is slower, and the surface coating is uniform. If the drying rate is too fast, the binder migration is more serious, resulting in surface non-uniformity, which will affect the adhesion between the carbon-coated layer and the surface of the foil body.

[0028] Furthermore, when coating the conductive paste on the surface of the current collector, the coating rate is 60 - 150 m / min.

[0029] In a third aspect, the present application provides an electrochemical energy storage device, which includes the above-mentioned high-adhesion and water-resistant coated current collector.

[0030] By using the high-adhesion and water-resistant coated current collector, the overall performance of the battery is significantly improved. On the one hand, there is a strong binding force between the coated carbon layer and the current collector, which is not easy to fall off, thus ensuring the stability and safety of the battery during charge and discharge. On the other hand, the coated carbon layer has strong water resistance and is suitable for various harsh environments, especially for batteries in aqueous systems, and can maintain high-efficiency conductive performance for a long time. In addition, due to the excellent conductive performance of the coated carbon layer, the internal resistance of the battery is reduced, and the energy conversion efficiency is improved. This electrochemical energy storage device shows excellent performance in practical applications and is suitable for wide applications in fields such as mobile electronic devices and electric vehicles.

[0031] In summary, the present application has the following beneficial effects: 1. In the modified binder of the present invention, the -OH group in the side chain group is prone to form hydrogen bonds in an aqueous solution, making the surface of the carbon material easier to wet, enhancing the conductivity. The presence of the main chain alkane group is prone to form entanglement with the surface of the carbon material, forming a highly cross-linked 3D network structure. At the same time, the combination of the side chain group and the carbon material further enhances hydrophobicity and also enhances ionic conductivity, reducing the internal resistance of the battery. The unique formula of the modified binder endows the coated carbon layer with excellent water resistance, enabling it to maintain good structural integrity and conductive performance in a high-humidity environment, effectively preventing electrochemical corrosion caused by water penetration, and extending the service life of the battery.

[0032] 2. The main chain group of the modified binder of the present invention shows certain hydrophobicity, and the side chain has groups such as -COOH, which will form hydrogen bonds with the surface of the current collector. By introducing the modified binder into the coated carbon layer, the adhesion between the coated carbon layer and the foil is significantly enhanced, solving the problems of poor coating adhesion and easy peeling in the prior art, and improving the stability and safety of the battery.

[0033] 3. The low viscosity (less than 90 mPa·s) of the conductive paste ensures uniform distribution during the coating process, avoids the phenomenon of uneven local thickness, improves the consistency and conductive efficiency of the coating, and further optimizes the overall performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of the coated current collector provided in Embodiment 1 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0035] The embodiments of the present invention will be described in detail below in conjunction with examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Specific conditions not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not specified as to the manufacturer can be obtained as conventional products commercially available.

[0036] The following will detail the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustration and explanation of the present invention, and are not used to limit the present invention.

[0037] Preparation Examples of Modified Binder Preparation Example 1 A modified binder, the preparation method of which includes: 1. Material preparation: 23 kg of ethyl methacrylate, 30 kg of n-butyl acrylate, 15 kg of isobornyl methacrylate, 40 kg of azobisisobutyronitrile (initiator), 30 kg of acrylonitrile, 15 kg of 2-hydroxyethyl methacrylate, and 20 kg of ethyl acetate.

[0038] 2. Add ethyl methacrylate, n-butyl acrylate, and isobornyl methacrylate into a reactor, add ethyl acetate and stir, control the reaction temperature between 73 °C, and at the same time add azobisisobutyronitrile for mixing, react for 3 h to obtain a prepolymer; 3. Add acrylonitrile and 2-hydroxyethyl methacrylate into the reaction solution containing the prepolymer for crosslinking reaction, control the reaction temperature at 82 °C, after 2 h, cool the reaction solution to room temperature to obtain the modified binder.

[0039] Preparation Example 2 A modified binder, which is different from Example 1 in that: the reaction temperature for synthesizing the prepolymer is 92 °C and the reaction time is 2 h.

[0040] Preparation Example 3 A modified binder, which is different from Example 1 in that: the reaction temperature for the crosslinking reaction is 98 °C and the reaction time is 1 h.

[0041] Preparation Example 4 A modified binder, which is different from Example 1 in that: add ethyl methacrylate, n-butyl acrylate, isobornyl methacrylate, acrylonitrile, and 2-hydroxyethyl methacrylate into ethyl acetate, control the reaction temperature at 82 °C, add azobisisobutyronitrile, after reacting for 5 h, cool the reaction solution to room temperature to obtain the modified binder.

[0042] Preparation Examples 5-9 Prepare materials according to Table 1, and the other steps are the same as those in Preparation Example 1.

[0043] Table 1 Examples

[0044] Example 1 A carbon-coated current collector with high adhesion and water resistance, as shown in the schematic diagram Figure 1 The preparation method thereof includes: 1. Using carbon black and conductive graphite (mass ratio 1:1) as conductive agents with particle size D50 ≤ 20 μm, and sodium carboxymethyl cellulose as a dispersant, prepare materials according to weight percentage: conductive agents 8 wt%, dispersant 1.6 wt%, modified binder (provided by Preparation Example 1) 11 wt%, and the balance is solvent.

[0045] 2. Disperse the dispersant and conductive agents in a solvent (deionized water) to obtain a conductive carbon solution, add the modified binder provided by Preparation Example 1 to the conductive carbon solution, and obtain a conductive paste after dispersion and mixing; 3. Coat the conductive paste on the surface of the foil body at a rate of 90 m / min, dry at 100 °C to form a carbon-coated layer, and obtain a functional carbon-coated current collector with super high water resistance on the surface and a surface density not greater than 0.7 g / m 2 ².

[0046] Examples 2 - 5 The difference between this group of examples and Example 1 lies in the selection of the modified binder. Specifically: In Example 2, the modified binder is provided by Preparation Example 2; In Example 3, the modified binder is provided by Preparation Example 3; In Example 4, the modified binder is provided by Preparation Example 5; In Example 5, the modified binder is provided by Preparation Example 6.

[0047] Example 6 The difference between this example and Example 1 lies in the formulation of the conductive paste: The conductive agent is a mixture of carbon fiber and carbon nanotubes with a mass ratio of 1:1, accounting for 10 wt%; The dispersant is polyvinylpyrrolidone, accounting for 2.8 wt%.

[0048] The modified binder is provided by Preparation Example 1, accounting for 15 wt%.

[0049] Example 7 The difference between this example and Example 1 lies in the formulation of the conductive paste: The conductive agent is a mixture of graphene and carbon nanotubes with a mass ratio of 1:1, accounting for 5.2 wt%; The dispersant is a polyalkylene oxide unsaturated monomer, with a proportion of 0.5 wt%.

[0050] The modified binder is provided by Preparation Example 1, with a proportion of 8.4 wt%.

[0051] Example 8 The difference between this example and Example 1 is as follows: 4. The conductive paste is coated on the surface of the foil body at a rate of 90 m / min and dried at a constant increasing temperature of 80°C - 90°C - 95°C - 105°C to form a carbon-coated layer. After drying, it is wound up to obtain a functional carbon-coated current collector.

[0052] Example 9 The difference between this example and Example 1 lies in the preparation process of the conductive paste: The dispersant and the conductive agent are dispersed in a solvent (deionized water) to obtain a conductive carbon solution. The modified binder provided by Preparation Example 1 is added to the conductive carbon solution to obtain a mixed solution. The mixed solution is subjected to sanding treatment and demagnetization treatment to obtain the conductive paste; Among them, the sanding treatment is carried out by grinding with a grinder for 5 cycles, the temperature is 20°C, and the time is 45 min; the demagnetization treatment is carried out by a slurry demagnetizer.

[0053] Comparative Example The difference between this group of comparative examples and Example 1 lies in the different selection of the modified binder. Specifically: Comparative Example 1, the modified binder is provided by Preparation Example 4; Comparative Example 2, the modified binder is provided by Preparation Example 7; Comparative Example 3, the modified binder is provided by Preparation Example 8; Comparative Example 4, the modified binder is provided by Preparation Example 9.

[0054] Performance Detection Test The carbon-coated current collectors provided by the examples and comparative examples are used for peel strength test and liquid absorption rate test: (1) Peel strength test: An MTS type electronic tensile testing machine is used to conduct a peel strength test in accordance with GB / T2792-2014 "Test Method for Peel Strength of Adhesive Tapes"; (2) Liquid absorption rate test: An electrolyte with a lithium salt (LiPF6) concentration of 1 M is prepared. The carbon-coated current collector is immersed in the above electrolyte at 25°C for 48 hours. The liquid absorption rate of the carbon-coated current collector is calculated according to the following formula: Liquid absorption rate = (m2 - m1 / m1) × 100%; Among them, the weight of the carbon-coated copper foil before soaking in the electrolyte is m1, and the weight of the composite current collector after soaking in the electrolyte is m2.

[0055] The test results are shown in Table 2 as follows: Table 2 Peeling force (N) Liquid absorption rate (%) Example 1 33.24 2.65 Example 2 31.47 2.88 Example 3 29.81 2.95 Example 4 31.06 3.23 Example 5 29.35 3.17 Example 6 34.51 2.51 Example 7 31.73 2.93 Example 8 35.68 2.53 Example 9 38.27 2.36 Comparative Example 1 18.25 5.72 Comparative Example 2 14.06 6.33 Comparative Example 3 19.17 8.23 Comparative Example 4 15.43 6.15 As can be seen from Table 2, the carbon-coated current collectors provided in Examples 1-9 of the present application have a large peel strength and a low liquid absorption rate, indicating that they have strong adhesiveness, which can ensure the long-term effectiveness and stability of the conductive layer; at the same time, they have strong water resistance, which can effectively prevent electrochemical corrosion caused by water penetration and extend the service life of the battery.

[0056] By comparing Example 1 and Example 8, it can be seen that after coating the conductive paste on the surface of the foil body and drying it at a constantly increasing temperature at a constant speed, it helps to improve the peel strength of the obtained carbon-coated current collector and reduce the liquid absorption rate of the carbon-coated current collector. This is because with this constantly increasing temperature at a constant speed, the drying rate of the conductive paste during the coating process is slower, and the surface coating is uniform. If the drying rate is fast, the migration of the binder is more serious, resulting in surface non-uniformity, which will affect the adhesion and water resistance between the carbon-coated layer and the surface of the foil body.

[0057] By comparing Example 1 and Example 9, it can be seen that performing sanding treatment and demagnetization treatment during the preparation of the conductive paste can further improve the adhesion and water resistance of the carbon-coated current collector. This is because the sanding treatment can make the conductive agent particles finer, reduce the presence of large particles, thereby improving the flatness and uniformity of the coating; the demagnetization treatment removes potential metal impurities and ensures the purity of the coating.

[0058] By comparing Example 1 and Comparative Example 1, it can be seen that during the preparation of the modified binder, by first performing a free radical polymerization reaction on ethyl methacrylate, n-butyl acrylate, and isobornyl methacrylate to form a prepolymer, and then cross-linking with acrylonitrile and 2-hydroxyethyl methacrylate, the cross-linking degree and uniformity of the modified binder can be effectively improved, thereby enhancing the adhesion between the carbon-coated layer and the foil body and improving the water resistance.

[0059] It can be seen from the comparison between Example 1 and Comparative Examples 2-4 that under the same preparation process, when the addition amount of 2-hydroxyethyl methacrylate in the modified binder is too small (Comparative Example 2), the addition amount of acrylonitrile is too small (Comparative Example 3), or when an equal amount of ethyl methacrylate and isobornyl methacrylate are used to replace n-butyl acrylate (Comparative Example 4), the adhesion and water resistance of the coated carbon current collector will be reduced to varying degrees. This is because the -CN in acrylonitrile has the function of improving water resistance and can enhance the corrosion resistance ability as a side chain in the molecular chain; 2-hydroxyethyl methacrylate has cross-linking characteristics. The -COOCH3 group in its molecule can greatly improve the adhesion, and the -OH group is an active group that can undergo esterification and cross-linking reactions. Introducing it into this adhesive mainly increases the cross-linking sites, thereby enhancing the adhesion; n-butyl acrylate is a soft monomer, which can improve the flexibility of the adhesive molecular chain, maintain the integrity of the overall chain segment during the cross-linking process, facilitate rapid film formation and infiltration on the foil after coating, and thus enhance the adhesion and water resistance.

[0060] This specific embodiment is only an explanation of the present application and does not limit the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A high-adhesion, water-resistant carbon-coated current collector, characterized in that: It includes a foil body and a carbon coating layer attached to the surface of the foil body; The conductive paste of the carbon coating layer comprises a conductive agent, a dispersant and a modified binder, and the viscosity of the conductive paste is less than 150 mPa·s; The modified binder comprises, by weight: 10-20 parts of isobornyl methacrylate, 20-40 parts of acrylonitrile, 15-30 parts of ethyl methacrylate, 25-35 parts of n-butyl acrylate, 10-20 parts of hydroxyethyl methacrylate, and 35-45 parts of initiator.

2. The high-adhesion, water-resistant carbon-coated current collector according to claim 1, characterized in that: The preparation method of the modified binder comprises: Dispersing ethyl methacrylate, n-butyl acrylate and isobornyl methacrylate in an organic solvent according to weight, adding an initiator under stirring to carry out a prepolymerization reaction; Then, acrylonitrile and hydroxyethyl methacrylate are added to carry out a cross-linking reaction, and the modified binder is obtained after cooling.

3. The high-adhesion, water-resistant carbon-coated current collector according to claim 1 or 2, characterized in that: When the initiator is added, the temperature of the reaction solution is controlled at 70-95° C., and the prepolymerization reaction time is 2-3 hours.

4. The high-adhesion, water-resistant carbon-coated current collector according to claim 1 or 2, characterized in that: The reaction temperature of the cross-linking reaction is 80-100° C., and the reaction time is 1-2 hours.

5. The high-adhesion, water-resistant carbon-coated current collector according to claim 1, characterized in that: The conductive paste comprises, by weight percentage, 5-10wt% of the conductive agent, 0.1-3wt% of the dispersant, 8-15wt% of the modified binder, and the remainder is solvent.

6. A method for preparing a high-adhesion, water-resistant carbon-coated current collector according to any one of claims 1 to 5, characterized in that: It includes: Dispersing the dispersant and the conductive agent in a solvent to obtain a conductive carbon solution; Adding the modified binder to the conductive carbon solution under stirring to obtain a conductive slurry after dispersion and mixing; The conductive paste is coated on the surface of the foil body, and a carbon coating layer is formed after drying, and the density of the carbon coating layer is less than 0.7 g / m 2 .

7. The method for preparing a high-adhesion, water-resistant carbon-coated current collector according to claim 6, characterized in that: The process of preparing the conductive paste also includes: The modified binder is added to the conductive carbon solution under stirring to obtain a mixed solution, and the mixed solution is subjected to sand grinding and demagnetization treatment to obtain the conductive slurry.

8. The method for preparing a high-adhesion, water-resistant carbon-coated current collector according to claim 7, characterized in that: The sand grinding process comprises: cyclically grinding the mixed solution at a grinding temperature of 15-25° C. and a grinding time of 30-60 min.

9. The method for preparing a high-adhesion, water-resistant carbon-coated current collector according to claim 7, characterized in that: After the conductive paste is coated on the surface of the foil body, it is dried in a constant increasing temperature range of 60-140°C.

10. An electrochemical energy storage device, characterized in that: It comprises the high-adhesion, water-resistant carbon-coated current collector as claimed in any one of claims 1 to 5.

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