High-adaptability conductive paste, preparation method thereof and application of high-adaptability conductive paste in carbon-coated current collector

Abstract

The invention relates to the technical field of new energy, in particular to high-adaptability conductive paste, a preparation method of the high-adaptability conductive paste and application of the high-adaptability conductive paste in a carbon-coated current collector. The high-adaptability conductive paste is composed of the following components in percentage by weight: 3.6-7.2% of a modified carbon material; 4.5-8% of a binder; the balance is a solvent; the modified carbon material is prepared by coating a carbon material with a coating material RnSiX (4-n), r in the coating material RnSiX (4-n) is a non-hydrolytic organic functional group, X is a hydrolyzable group, and the value range of n is 1-3. According to the preparation method, the carbon material is pretreated, so that the spreadability, dispersity and adhesion performance of the slurry on the aluminum foil are remarkably improved, and the slurry is further suitable for aluminum foils of most specifications and in an oil stain state.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and more specifically, to a highly adaptable conductive slurry, a preparation method thereof, and an application thereof in a carbon-coated current collector. Background Art

[0002] Carbon-coated current collectors are composite materials consisting of foil and surface-coated conductive materials. As a key component of batteries, they are widely used in electrochemical energy storage devices such as lithium-ion batteries and sodium-ion batteries. Their quality will directly affect the overall performance of the battery.

[0003] During the production process, the foil will be contaminated with oil, impurities and other pollutants, so the cleaning process is crucial. However, due to the different cleaning fluid compositions and cleaning purposes used by different manufacturers, the amount of residual oil in the aluminum foil of different manufacturers varies greatly, which is not conducive to downstream processing.

[0004] In related technologies, such as CN202310888585.4, corona treatment is also performed on aluminum foil instead of cleaning. However, the surface oil and dirt conditions of the treated aluminum foil still vary greatly. Therefore, when downstream manufacturers reprocess it, there are still problems such as uneven coating distribution, coating leakage, poor coating adhesion and shedding. In summary, in order to overcome the negative impact of foil material differences on its performance, the present application specifically provides a highly adaptable conductive slurry, a preparation method thereof, and an application in a carbon-coated current collector. Summary of the Invention

[0005] In order to overcome the negative impact of foil material differences on actual performance, the present application provides a highly adaptable conductive slurry, its preparation method and application in carbon-coated current collectors, that is, by pretreating the carbon material, the spreadability, dispersibility and adhesion performance of the slurry on aluminum foil are significantly improved, and it is then suitable for aluminum foils of most specifications and oily states.

[0006] In the first aspect, the present application provides a highly adaptable conductive paste, which adopts the following technical solution: A highly adaptable conductive paste, comprising the following components in the following weight ratios: Modified carbon material 3.6-7.2%; binder 4.5-8%; the balance is solvent; The modified carbon material is a carbon material coated with a coating material R n SiX (4-n) Coated; The coating material R n SiX (4-n) R is a non-hydrolyzable organic functional group, X is a hydrolyzable group, and the value of n ranges from 1 to 3.

[0007] By adopting the above technical solution, the carbon material is coated with the material Rn SiX (4-n) The modified carbon material obtained by coating is n SiX (4-n) The coating modification takes into account the excellent spreadability, dispersibility and adhesion performance, and can meet the surface oil pollution conditions of most foils; Combining the actual application effect and the single variable of ingredients, the analysis of its principles may be as follows: 1) The improvement of its spreadability and dispersibility is due to the chemical bonding and physical adsorption effect between the R group and the surface of the carbon material, which effectively reduces the agglomeration of carbon particles and makes the slurry more uniform; 2) The improvement in adhesion is mainly due to the reaction between the hydrolyzed group (X) and the functional groups on the aluminum foil surface to form an interface bridge, which significantly improves the bonding strength between the coating and the substrate (adhesion ≥ 5B).

[0008] Preferably, the carbon material and the coating material R n SiX (4-n) The weight ratio is 1:(0.002-0.06).

[0009] By adopting the above technical solution, the coating rate of the modified carbon material under this ratio is balanced and controlled, ensuring that the surface of the carbon material is fully covered without redundant coating. It is not easy for the conductivity to be hindered by excessive coating agent, nor is it easy for the dispersion to be reduced due to insufficient coating.

[0010] Preferably, the non-hydrolyzable organic functional group is selected from methyl, vinyl, amino, epoxy, mercapto or acryloxypropyl.

[0011] By adopting the above technical solution, the selected non-hydrolyzable organic functional groups can all combine with the surface defect sites of the carbon material to ensure the stability of the coating layer. In addition, the amino and acryloxypropyl groups are also beneficial to the subsequent slurry compatibility and curing cross-linking effect.

[0012] Preferably, the hydrolyzable group is selected from alkoxy, aryloxy, acyloxy, polyurethane, acrylic, -CH2CH2O-, n-vinylamide, phthalic acid, -NH-CO-O- (carbamate), and -NCO (isocyanate).

[0013] By adopting the above technical solution, the selected hydrolysis group takes into account both the controllability of hydrolysis and the cross-section enhancement effect. In addition to the moderate hydrolysis rate, which is not prone to uneven coating due to excessive reaction, partial hydrolysis will also generate hydroxyl groups, which condense with the hydroxyl groups on the surface of the aluminum foil, thereby improving the adhesion.

[0014] Preferably, the coating material R n SiX (4-n) Specifically, aminotriethoxysilane.

[0015] In a second aspect, the present application provides a method for preparing the highly adaptable conductive paste, comprising the following steps: S1, first disperse the carbon material in the coating material and ultrasonically treat for 10-30 minutes; S2, stirring and reacting at 60-80°C for 1-3 hours to form a uniform slurry; S3, then centrifugally drying the slurry to obtain a modified carbon material; S4. The modified carbon material obtained in S3 is mixed with a solvent and a binder in a corresponding weight ratio, and ball-milled to a particle size of ≤1 μm to obtain a conductive paste.

[0016] By adopting the above technical solution, the preparation process is significantly simplified, and the controllability is high. Various conditions are easy to operate and achieve, which is beneficial to the stability and reaction sufficiency of the product, and can effectively meet the needs of conductive slurry and its application in current collector.

[0017] In a third aspect, the present application provides an application of any of the above-mentioned conductive pastes or the conductive paste obtained by the above-mentioned preparation method in a carbon-coated current collector, using the following technical solution: The method comprises the following steps: coating the conductive slurry on the surface of the aluminum foil, drying at 80-150° C. and then curing to form a conductive coating with a thickness of 0.01-10 μm.

[0018] In a fourth aspect, the present application provides a highly adaptable carbon-coated current collector, comprising an aluminum foil substrate and a coating formed by any of the above-mentioned conductive pastes or the conductive pastes obtained by the above-mentioned preparation methods.

[0019] In a fifth aspect, the present application provides an energy storage device comprising the above-mentioned carbon-coated current collector.

[0020] In a sixth aspect, the present application provides a modified carbon material, which adopts the following technical solution: A modified carbon material, comprising a carbon material and a coating material R n SiX (4-n) The mixture is prepared by blending and modifying in a weight ratio of 1:(0.002-0.06). The specific steps are as follows: A1. First, disperse the carbon material in the coating material and ultrasonicate for 10-30 minutes; A2, stirring and reacting at 60-80°C for 1-3 hours to form a uniform slurry; A3, then centrifugally drying the slurry to obtain a modified carbon material; The coating material R n SiX (4-n) The value of n in the range is 1-3; The R is a non-hydrolyzable organic functional group selected from methyl, vinyl, amino, epoxy, mercapto or acryloyloxypropyl; The X is a hydrolyzable group selected from alkoxy, aryloxy, acyloxy, polyurethane, acrylic, -CH2CH2O-, n-vinylamide, phthalic acid, -NH-CO-O- (carbamate), and -NCO (isocyanate).

[0021] By adopting the above technical solution, the carbon material is coated with the material R n SiX (4-n) The modified carbon material obtained by coating has excellent chemical bonding and physical adsorption effects under the action of the coating layer, and is not prone to carbon particle agglomeration. It is suitable for any field that requires dispersed carbon materials.

[0022] In summary, this application has the following beneficial effects: 1. This application is made of carbon material coated with material R n SiX (4-n) The modified carbon material obtained by coating is n SiX (4-n) The coating modification takes into account the excellent spreadability, dispersibility and adhesion performance, and can meet the surface oil pollution conditions of most foils; 2. The preparation process in this application is significantly simplified while being highly controllable. All conditions are easy to operate and achieve, which is beneficial to the stability and reaction sufficiency of the product and can effectively meet the requirements of the conductive paste and its application in the current collector; 3. The carbon material in this application is coated with the material R n SiX (4-n) The modified carbon material obtained by coating has excellent chemical bonding and physical adsorption effects under the action of the coating layer, and is not prone to carbon particle agglomeration. It is suitable for any field that requires dispersed carbon materials. DETAILED DESCRIPTION

[0023] The present application is further described in detail below with reference to the embodiments.

[0024] Preparation Example Preparation Examples 1-5 A modified carbon material, comprising a carbon material and a coating material R n SiX (4-n) The mixture is prepared by blending and modifying according to the corresponding weight parts in the table below. The specific steps are as follows: A1. First, disperse the carbon material in the coating material and ultrasonically treat for 20 minutes; The carbon material is carbon black with a particle size of 200 nm; A2, stirring and reacting at 65°C for 2 hours to form a uniform slurry; A3, then centrifugally drying the slurry to obtain a modified carbon material; The coating material R n SiX (4-n) Where n is 1, R is a non-hydrolyzable organic functional group selected from methyl, X is a hydrolyzable group selected from alkoxy-methoxy, R n SiX (4-n) The coating material is specifically methyltrimethoxysilane.

[0025] Table: Components and corresponding weights in Preparation Examples 1-5 (kg) Preparation Examples 6-10 A modified carbon material, which is different from Preparation Example 3 in that the coating material R n SiX (4-n) The usage is different, as shown in the following table: Table: Selection of coating material RnSiX(4-n) in preparation examples 6-10 The performance test was conducted by selecting the conductive pastes prepared in the examples and comparative examples as test objects, and coating the obtained conductive pastes on aluminum foils with a thickness of 2 μm (oil contamination levels of A, B, and C, respectively); Aluminum foil A: oil content is 2mg / m 2 ; Aluminum foil B: oil content is 5mg / m 2 ; Aluminum foil C: oil content is 10mg / m 2 ; After drying at 120°C and curing, a conductive coating with a thickness of 1 μm is formed. The coating adhesion, conductivity, coating leakage rate and dispersion are then tested. The specific testing standards and steps are as follows: Coating adhesion test: Use a blade to draw a 1mm x 1mm orthogonal grid on the coating surface (depth to the aluminum foil substrate), and test the areas with different loadings separately; Apply special tape (3M Type 600) to the grid area, press firmly, and then peel it off vertically and quickly. Observe the proportion of the peeled area under a microscope. The specific test standard refers to the ASTM D3359 cross-cut method.

[0026] Conductivity test: Use a four-terminal sheet resistance meter (ACCF-G2A) at a pressure of 25 MPa to test five points within the area. After removing outliers, take the average value to measure the diaphragm resistance. Specific reference is made to the ASTM F390 standard.

[0027] Missing coating rate test: Randomly select a 10cm x 10cm coating area and scan the surface using a terahertz micrometer probe (resolution ≤ 5μm). Identify the exposed areas of aluminum foil not covered with slurry and calculate the percentage of missing coating area: Missing coating rate = exposed area / total test area x 100%.

[0028] Dispersion uniformity test: Take the cured carbon-coated current collector and randomly select 5 fields of view (×50,000) for observation via transmission electron microscopy (TEM). The size and spacing of carbon particle agglomerates are counted, and the degree of uniformity, obvious agglomeration, and localized agglomeration are calculated. For specific reference, refer to the standard GB / T 21868.3. Example

[0029] Examples 1-5 A highly adaptable conductive paste, the components and their corresponding weights are shown in the following table: Table: Components and corresponding weights in Examples 1-5 (kg) The modified carbon material is prepared by dispersing and mixing the components at room temperature at 1500 r / min for 20 minutes, wherein the modified carbon material is prepared by Preparation Example 3, the binder is acrylic resin with CAS No. 9003-01-4, and the solvent is water.

[0030] Comparative Example 1 A conductive paste is different from Example 1 in that its modified carbon material is replaced by an equal amount of carbon material (the carbon material is carbon black with a particle size of 200 nm), and the rest is the same as Example 1.

[0031] Comparative Example 2 A conductive paste, which is different from Example 1 in that its modified carbon material is replaced by an equal amount of carbon material (the carbon material is carbon black with a particle size of 200 nm), and before coating, the aluminum foil is corona treated in a single group of 8KW, a total of 4 groups of corona machines at a speed of 80m / min.

[0032] Comparative Example 3 A conductive paste, which is different from Example 1 in that the amount of the modified carbon material used is 1.8 kg, and the rest is the same as Example 1.

[0033] The conductive pastes prepared in Examples 1-5 and Comparative Examples 1-3 were tested for coating adhesion, conductivity, coating leak rate, and dispersibility when applied on different aluminum foils (A / B / C) according to the above measurement procedures and measurement standards. The average values ​​of the test results are recorded in Tables 1-4 below.

[0034] Table 1: Coating adhesion performance test results Table 2: Conductivity test results Table 3: Missing coating rate test results Table 4: Dispersion uniformity test results As can be seen from Tables 1-4 above, the highly adaptable conductive pastes prepared in Examples 1-5 have excellent spreadability, dispersibility, and adhesion properties, and can be used to meet the surface oil contamination conditions of most foils (refer to aluminum foil A, aluminum foil B, and aluminum foil C in this application); The highly adaptable conductive pastes in Examples 1-5 of the present application in Table 1 have an adhesion of ≥4B when applied to any of aluminum foil A, aluminum foil B, and aluminum foil C; Since comparative examples 1-2 use conventional carbon materials, even after corona treatment, the adhesion performance is still ≤4B when applied to aluminum foil B and aluminum foil C with highly oily surfaces. As for comparative example 3, since the amount of modified carbon material used is too low, its performance cannot achieve the expected effect.

[0035] The highly adaptable conductive pastes in Examples 1-5 of the present application in Table 2 have a resistance of 1.98-2.76 (mΩ), which are improved to varying degrees compared to Comparative Examples 1-2 using ordinary carbon materials and Comparative Example 3 with insufficient neutralization dosage. This performance is not related to the oil stain state on the aluminum foil surface, but only to the leakage rate.

[0036] The highly adaptable conductive pastes in Examples 1-5 of the present application in Table 3 have a non-coating rate of ≦1.8% when applied to any of aluminum foil A, aluminum foil B, and aluminum foil C. Since comparative examples 1-2 use conventional carbon materials, even after corona treatment, the leakage rate is still ≥6.1 when applied to aluminum foil A, aluminum foil B and aluminum foil C. As for comparative example 3, since the amount of modified carbon material used is too low, its performance also fails to achieve the expected effect.

[0037] The highly adaptable conductive pastes in Examples 1-5 of the present application in Table 4 have uniform dispersion uniformity when applied to any of aluminum foil A, aluminum foil B, and aluminum foil C, which are significantly improved compared to Comparative Examples 1-3 and are not easily affected by the choice of aluminum foil (i.e., differences in surface oil stain status).

[0038] In summary, it can be seen that the highly adaptable conductive paste in this application is preferably composed of the following components in the following weight ratios: 3.6-7.2% of modified carbon material; 4.5-8% of binder; and the balance being solvent. Any adjustment within the above range can produce a conductive paste with stable and uniform performance. Combining the data of each group, the principle may be deduced as follows: 1) The improvement of its spreadability and dispersibility is due to the chemical bonding and physical adsorption effect between the R group and the surface of the carbon material, which effectively reduces the agglomeration of carbon particles and makes the slurry more uniform; 2) The improvement in adhesion is mainly due to the reaction between the hydrolyzed group (X) and the functional groups on the aluminum foil surface to form an interface bridge, which significantly improves the bonding strength between the coating and the substrate (adhesion ≥ 5B).

[0039] In addition, from the data in the above table, we can also know that: n SiX (4-n) The modified carbon material obtained by coating has excellent chemical bonding and physical adsorption properties under the action of the coating layer, and is not prone to carbon particle agglomeration. It is suitable for any field that requires the dispersion of carbon materials.

[0040] Examples 6-9 A highly adaptable conductive paste is different from Example 1 in that the modified carbon material is used in different circumstances. The specific corresponding relationships are shown in the table below.

[0041] Table: Comparison of usage of modified carbon materials in Examples 6-9 The conductive pastes prepared in Examples 6-9 were taken and tested for coating adhesion, conductivity, coating leak rate and dispersibility when coated on different aluminum foils (A / B / C) according to the above measurement steps and measurement standards. The average values ​​of the test results are recorded in Tables 5-8 below.

[0042] Table 5: Coating adhesion performance test results Table 6: Conductivity test results Table 7: Missing coating rate test results Table 8: Dispersion uniformity test results As can be seen from Tables 5-8 above, the highly adaptable conductive pastes prepared in Examples 6-9 have a certain degree of spreadability, dispersibility, and adhesion performance, and can meet the surface oil contamination conditions of most foils (refer to aluminum foil A, aluminum foil B, and aluminum foil C in this application); In Table 5, only the highly adaptable conductive pastes in Examples 8-9 of the present application have an adhesion of ≥5B when applied to any of aluminum foil A, aluminum foil B and aluminum foil C. As for Examples 6-7, due to the adjustment of the component ratio, their coverage is unbalanced, resulting in their performance failing to achieve the expected effect.

[0043] In Table 6, only the highly adaptable conductive pastes in Examples 8-9 of the present application have good conductive properties, with a resistance of 2.4-2.6 (mΩ), which are improved to varying degrees compared to Examples 6-7 with unbalanced ratios, and this performance is unrelated to the oil stain state on the aluminum foil surface.

[0044] In Table 7, only the highly adaptable conductive paste in Examples 8-9 of the present application has a non-coating rate of ≦1.5% when applied to any of aluminum foil A, aluminum foil B and aluminum foil C. As for Examples 6-7, due to the adjustment of the component ratio, the coverage rate is unbalanced, resulting in its performance also failing to achieve the expected effect.

[0045] In Table 8, only the highly adaptable conductive pastes in Examples 8-9 of the present application have uniform dispersion uniformity when applied to any of aluminum foil A, aluminum foil B, and aluminum foil C. Examples 6-7 also do not exhibit agglomeration phenomenon, indicating that they are not easily affected by differences in the oil stain state on the aluminum foil surface.

[0046] In summary, carbon materials and coating materials R n SiX (4-n) The preferred weight ratio is 1:(0.002-0.06). Only under this ratio can the coverage rate of the modified carbon material be balanced and controlled, ensuring that the surface of the carbon material is fully covered without redundant coating. It is not easy for the conductivity to be hindered by excessive coating agent, nor is it easy for the dispersion to decrease due to insufficient coating.

[0047] Examples 10-14 A highly adaptable conductive paste is different from Example 1 in that the modified carbon material is used in different circumstances. The specific corresponding relationships are shown in the table below.

[0048] Table: Comparison of usage of modified carbon materials in Examples 10-14 Group Modified carbon materials Example 10 Prepared from Preparation Example 6 Example 11 Prepared from Preparation Example 7 Example 12 Prepared from Preparation Example 8 Example 13 Prepared from Preparation Example 9 Example 14 Prepared from Preparation Example 10 The conductive pastes prepared in Examples 10-14 were tested for coating adhesion, conductivity, coating leak rate, and dispersibility when applied on different aluminum foils (A / B / C) according to the above measurement procedures and measurement standards. The average values ​​of the test results are recorded in Tables 9-12 below.

[0049] Table 9: Coating adhesion performance test results Table 10: Conductivity test results Table 11: Missing coating rate test results Table 12: Dispersion uniformity test results As can be seen from Tables 9-12 above, the highly adaptable conductive pastes prepared in Examples 10-14 have at least one of spreadability, dispersibility, and adhesion properties, and can be used to meet the surface oil contamination conditions of most foils (refer to aluminum foil A, aluminum foil B, and aluminum foil C in this application); Its theoretical basis comes from the modification analysis and deduction of carbon materials, as follows: 1) The selected non-hydrolyzable organic functional groups can all combine with the surface defect sites of the carbon material to ensure the stability of the coating layer. In addition, the amino and acryloxypropyl groups are also beneficial to the subsequent slurry compatibility and curing cross-linking effect.

[0050] 2) The selected hydrolysis groups take into account both hydrolysis controllability and cross-sectional enhancement effects. In addition to the moderate hydrolysis rate, which is not prone to uneven coating due to excessive reaction, partial hydrolysis will also generate hydroxyl groups, which condense with the hydroxyl groups on the aluminum foil surface, thereby improving adhesion.

[0051] However, the above-mentioned coating material R n SiX (4-n) When put into use, it was found that there were discrepancies between theory and practice. Only Example 10 had excellent performance. The reasons may be as follows: Example 11, i.e., Preparation Example 7, when the coating material R n SiX (4-n) When the value of n is 2, specifically dimethyldiacetoxysilane, its conductive properties are significantly reduced. It is speculated that the reason is that the acetoxy group is hydrolyzed, which in turn causes local acid corrosion of the carbon material.

[0052] Example 12, i.e., Preparation Example 8, when the coating material R n SiX (4-n) When n is 2, specifically methylvinyldimethoxysilane, its adhesion is significantly reduced, especially when applied to aluminum foil B and aluminum foil C. The reason is speculated to be that the vinyl group tends to form a cross-linked network with excessive rigidity, which in turn limits the interfacial stress release of the carbon material and makes it easy to peel off.

[0053] Example 13, i.e., Preparation Example 9, when the coating material R n SiX (4-n)When the value of n is 3, specifically trimethylaminosilane, its dispersibility is poor and the carbon material is prone to agglomeration. The reason is speculated to be: the amino group density is low and the steric hindrance is large, which in turn affects the combination with the carbon material, resulting in uneven coating of the carbon material, which in turn affects the dispersion effect.

[0054] Example 14, i.e., Preparation Example 10, when the coating material R n SiX (4-n) When the value of n is 3, specifically triphenylethoxysilane, its conductive properties are also affected and significantly increased. The reason is speculated to be that the relative volume of the phenyl group is too large, which in turn hinders the movement of the molecular chain segments, resulting in continuous damage to the conductive network and is not conducive to the coverage of its coating layer.

[0055] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A highly adaptable conductive paste, characterized in that: It is composed of the following components in the following weight ratios: Modified carbon material 3.6-7.2%; binder 4.5-8%; the balance is solvent; The modified carbon material is a carbon material coated with a coating material R n SiX （4-n） Coated; The coating material R n SiX （4-n） R is a non-hydrolyzable organic functional group, X is a hydrolyzable group, and the value of n ranges from 1 to 3.

2. The highly adaptable conductive paste according to claim 1, characterized in that: The carbon material and the coating material R n SiX （4-n） The weight ratio is 1:(0.002-0.06).

3. The highly adaptable conductive paste according to claim 2, characterized in that: The non-hydrolyzable organic functional group is selected from methyl, vinyl, amino, epoxy, mercapto or acryloxypropyl.

4. The highly adaptable conductive paste according to claim 2, characterized in that: The hydrolyzable group is selected from alkoxy, aryloxy, acyloxy, polyurethane, acrylic, -CH2CH2O-, n-vinylamide, phthalic acid, -NH-CO-O- (carbamate), and -NCO (isocyanate).

5. The highly adaptable conductive paste according to claim 2, characterized in that: The coating material R n SiX （4-n） Specifically, aminotriethoxysilane.

6. The method for preparing the highly adaptable conductive paste according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, first disperse the carbon material in the coating material and ultrasonically treat for 10-30 minutes; S2, stirring and reacting at 60-80°C for 1-3 hours to form a uniform slurry; S3, then centrifugally drying the slurry to obtain a modified carbon material; S4. The modified carbon material obtained in S3 is mixed with a solvent and a binder in a corresponding weight ratio, and ball-milled to a particle size of ≤1 μm to obtain a conductive paste.

7. Use of the conductive paste according to any one of claims 1 to 5 or the conductive paste prepared according to claim 6 in a carbon-coated current collector, characterized in that: The following steps are involved: The conductive paste is coated on the surface of the aluminum foil, dried at 80-120° C. and then solidified to form a conductive coating with a thickness of 0.5-3 μm.

8. A highly adaptable carbon-coated current collector, characterized in that: The invention comprises an aluminum foil substrate and a coating formed by the conductive paste according to any one of claims 1 to 5 or the conductive paste prepared according to claim 6.

9. An energy storage device, characterized in that: Comprising the carbon-coated current collector according to claim 7.

10. A modified carbon material, characterized in that: Made of carbon material and coating material R n SiX （4-n） The mixture is prepared by blending and modifying in a weight ratio of 1:(0.002-0.06). The specific steps are as follows: A1. First, disperse the carbon material in the coating material and ultrasonicate for 10-30 minutes; A2, stirring and reacting at 60-80°C for 1-3 hours to form a uniform slurry; A3, then centrifugally drying the slurry to obtain a modified carbon material; The coating material R n SiX （4-n） The value of n in the range is 1-3; The R is a non-hydrolyzable organic functional group selected from methyl, vinyl, amino, epoxy, mercapto or acryloyloxypropyl; The X is a hydrolyzable group, and the hydrolyzable group is selected from alkoxy, aryloxy, acyloxy, polyurethane, acrylic, -CH2CH2O-, n-vinylamide, phthalic acid, -NH-CO-O- (carbamate), and -NCO (isocyanate).

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