A method for producing a carbon-coated copper foil

Abstract

A preparation method of carbon-coated copper foil, comprising the following steps: S1, placing a graphite carbon plate as a cathode and an electrolytic copper foil anode plate as an anode in an electrolyte, wherein the electrolyte is a copper sulfate solution containing an additive; S2, performing electrochemical deposition at a calibrated temperature and a calibrated current to form an electrolytic copper foil on the surface of the graphite carbon plate; S3, after termination of the deposition, rinsing the surface of the electrolytic copper foil with pure water, and then drying the electrolytic copper foil; S4, peeling the electrolytic copper foil from the graphite carbon plate to obtain a carbon-coated copper foil product. The method combines the carbon coating process with the foil forming process of the electrolytic copper foil, directly deposits electrolytic copper foils of different specifications on the graphite carbon plate, and then peels off to obtain the carbon-coated copper foil product. Compared with the traditional carbon coating process, the present application has the advantages of simple equipment, convenient operation, low cost, etc., and significantly improves the preparation efficiency.

Description

Technical Field

[0001] This invention relates to the field of battery current collector technology, and more specifically to a method for preparing carbon-coated copper foil. Background Technology

[0002] With the development of the new energy market, higher requirements are being placed on the energy density and rate performance of power lithium-ion batteries. Copper foil is an important component of lithium-ion batteries, mainly used as the current collector in the cathode material. Conventional copper foil is a smooth foil. If a layer of carbon-based conductive material (such as graphite, CNT, or graphene) is coated on the surface of the copper foil, it is called carbon-coated copper foil. Compared with smooth copper foil, carbon-coated copper foil can not only reduce the ohmic impedance of the electrode, but also enhance the bonding strength between the negative electrode slurry and the current collector. In addition, due to the good conductivity of the coated carbon layer, carbon-coated copper foil can also reduce the amount of conductive agent and binder used, thereby improving the cycle life of the battery.

[0003] Existing carbon coating processes mainly include the following methods:

[0004] 1. Wet coating method: Conductive carbon material is mixed with a binder to form a slurry, which is then coated onto the surface of copper foil and dried for curing. This method relies on the binder, and cracks and pores are easily generated during the drying process, reducing conductivity; the binder may cover conductive particles, increasing interfacial resistance, and organic solvents may cause pollution.

[0005] 2. Vapor deposition: In a vacuum environment, copper foil is bombarded with plasma to create a rough surface, followed by the deposition of a metallic dielectric layer (such as nickel or chromium), and finally, carbon atoms are deposited to form a carbon film. This method has high equipment costs, complex processes, low deposition rates, and is difficult to mass-produce; the carbon film has low bonding strength with the substrate and is prone to delamination.

[0006] 3. Transfer method: First, a carbon coating is prepared on a temporary substrate to form an independent thin film, and then transferred to the surface of copper foil by hot pressing. This transfer process is prone to wrinkles and bubbles, and the process steps are complex and costly; the interfacial adhesion is weak, affecting conductivity and mechanical strength.

[0007] 4. In-situ growth method: Carbon nanomaterials (such as carbon nanotubes and graphene) are directly catalytically grown on the surface of copper foil to form an integrated structure. This method has stringent requirements for catalysts and growth conditions (temperature, gas ratio), and is difficult to control for uniformity; it is also costly and has a low yield.

[0008] In summary, existing technologies generally suffer from problems such as complex processes, high equipment costs, demanding preparation conditions, and difficulties in parameter control; at the same time, they still face significant challenges in terms of coating uniformity, adhesion, production costs, and environmental friendliness. Summary of the Invention

[0009] This invention addresses the problems of complex, costly, and inefficient existing carbon-coated copper foil processes by proposing an innovative, simple, efficient, and low-cost preparation method.

[0010] A method for preparing carbon-coated copper foil includes the following steps:

[0011] S1. A graphite carbon plate is used as the cathode and an electrolytic copper foil anode plate is used as the anode. The plates are placed in an electrolyte, which is a copper sulfate solution containing additives.

[0012] S2. Electrochemical deposition is performed at a calibrated temperature and calibrated current to form an electrolytic copper foil on the surface of the graphite carbon plate;

[0013] S3. After terminating the deposition, rinse the surface of the electrolytic copper foil with pure water, and then dry the electrolytic copper foil.

[0014] S4. Peel the electrolytic copper foil from the graphite carbon plate to obtain the finished carbon-coated copper foil.

[0015] This method directly forms electrolytic copper foil on the surface of a graphite carbon plate through an electrochemical deposition process. It eliminates the need for complex equipment and binders required in traditional carbon coating processes, simplifying the operation, reducing process difficulty, and lowering raw material and equipment costs. This not only facilitates large-scale application but also reduces the risk of uneven coating, cracks, porosity, or delamination caused by complex operations, thereby improving product consistency and reliability. Furthermore, this method integrates the carbon coating and electrolytic copper foil production processes into a continuous step, significantly increasing the output per unit time and shortening the production cycle compared to traditional multi-step processes.

[0016] Furthermore, in step S1, the electroplated surface of the graphite carbon plate is first polished with 2000-grit sandpaper and washed with water to improve the surface smoothness of the graphite carbon plate, so that the carbon layer peeled off in subsequent steps is more uniform.

[0017] Furthermore, the electrolytic copper foil anode plate is a titanium-based coated anode, which has strong corrosion resistance, uniform current distribution, and improves the thickness consistency of the deposited copper foil.

[0018] Furthermore, the additives include brighteners, leveling agents, and wetting agents.

[0019] Preferably, the mass concentration ratio of the brightener, leveling agent, and wetting agent is 1:(0.2-0.4):(1-2). The brightener promotes the formation of dense grains and improves the surface smoothness of the copper foil; the leveling agent inhibits dendrite growth and ensures uniform copper foil thickness; and the wetting agent reduces the surface tension of the electrolyte and eliminates air bubbles.

[0020] Preferably, the brightener is an organic compound containing a sodium sulfonate group.

[0021] Preferably, the leveling agent is an amine organic compound.

[0022] Preferably, the wetting agent is one or more of collagen polymers, cellulose polymers, and polyethers.

[0023] Furthermore, the calibration temperature is 50–55°C to maintain the migration rate of ions in the electrolyte and avoid high temperature causing additive decomposition or low temperature causing low deposition efficiency.

[0024] Furthermore, the calibration current is 10–50 A / dm. 2 It can adapt to different preparation conditions and copper foil of different thicknesses. Attached Figure Description

[0025] Figure 1 This is a flowchart of the preparation method of carbon-coated copper foil according to the present invention.

[0026] Figure 2 This is a photograph of the electroplated graphite carbon plate of Embodiment 1 of the present invention.

[0027] Figure 3 This is a photograph of carbon-coated copper foil from Embodiment 1 of the present invention.

[0028] Figure 4 This is a SEM image of carbon-coated copper foil from Embodiment 1 of the present invention.

[0029] Figure 5 This is a copper element distribution diagram of the carbon-coated copper foil in Embodiment 1 of the present invention.

[0030] Figure 6 This is a carbon element distribution diagram of the carbon-coated copper foil in Embodiment 1 of the present invention.

[0031] Figure 7 This is the EDS energy spectrum of carbon-coated copper foil in Example 1 of the present invention.

[0032] Figure 8 This is a photograph of carbon-coated copper foil from Embodiment 2 of the present invention.

[0033] Figure 9 This is a photograph of carbon-coated copper foil from Embodiment 3 of the present invention. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] Example 1

[0037] A method for preparing carbon-coated copper foil includes the following steps:

[0038] S101, Prepare the electrolyte, wherein Cu 2+ The concentration is 90 g / L, the H2SO4 concentration is 100 g / L, and the Cl concentration is... - The electrolyte is 10 ppm, the brightener is 10 ppm sodium didithiopropane sulfonate, the leveling agent is 2 ppm 2-mercaptothiazoline, and the wetting agent is 12 ppm of collagen, hydroxyethyl cellulose, and polyethylene glycol compounded in a 6:1:5 ratio. The electrolyte is added to the electrolytic cell.

[0039] S102. Take a high-purity graphite carbon plate, polish it with 2000-grit sandpaper, and then rinse it with water.

[0040] S103. Place the titanium-based coated anode and the graphite carbon plate into an electrolytic cell. The graphite carbon plate is connected to the negative terminal of the power supply, and the titanium-based coated anode plate is connected to the positive terminal of the power supply. The distance between the graphite carbon plate and the titanium-based coated anode is 10mm.

[0041] S104. The electrolyte temperature is raised to between 50 and 55°C using a heating rod, air is introduced for stirring, and the power supply current density is set to 20A / dm³. 2 Electroplating for 1 minute forms an electrolytic copper foil (e.g., ...) on the surface of the graphite carbon plate. Figure 2 (As shown).

[0042] S105. Remove the graphite carbon plate, rinse the surface of the electrolytic copper foil with water, dry it, and peel the electrolytic copper foil off the graphite carbon plate to obtain the following: Figure 3 The 6-micrometer carbon-coated copper foil shown.

[0043] Elemental analysis (EDS) was performed on the surface of the carbon-coated copper foil prepared in this embodiment. (See attached document.) Figures 4 to 7 ,in, Figure 4 SEM images of the surface morphology of carbon-coated copper foil. Figure 5 This is a diagram showing the copper element distribution in carbon-coated copper foil. Figure 6 This is a carbon element distribution diagram of carbon-coated copper foil. Figure 7The image shows the EDS spectrum of the carbon-coated copper foil. The experimental results indicate that the carbon-coated copper foil is mainly composed of two elements, Cu and C, with C evenly distributed on the surface of the copper foil; it also contains trace amounts of O, mainly derived from copper oxide formed on the copper surface.

[0044] Furthermore, the surface resistance of the carbon-coated copper foil prepared in this embodiment was measured at multiple points using the four-probe method and compared with that of the uncoated copper foil prepared under the same conditions using a titanium plate as the cathode. The results are shown in Table 1.

[0045] Table 1

[0046]

[0047] Therefore, it can be seen that the carbon-coated copper foil prepared by the method of this embodiment has a uniform carbon layer distribution, no other impurities are introduced, and it has a smaller surface resistance than the uncoated copper foil of the same specifications. Thus, this method can achieve the purpose of preparing carbon-coated copper foil.

[0048] Example 2

[0049] A method for preparing carbon-coated copper foil includes the following steps:

[0050] S111, Prepare the electrolyte, wherein Cu 2+ The concentration is 90 g / L, the H2SO4 concentration is 100 g / L, and the Cl concentration is... - The electrolyte is 10 ppm, the brightener is 10 ppm polyisothiourea propanesulfonic acid inner salt, the leveling agent is 3 ppm 2-mercaptothiazoline, and the wetting agent is 15 ppm collagen, hydroxyethyl cellulose and polyethylene glycol compounded in a 9:1:5 ratio. The electrolyte is added to the electrolytic cell.

[0051] S112. Take a high-purity graphite carbon plate, polish it with 2000-grit sandpaper, and then rinse it with water.

[0052] S113. Place the titanium-based coated anode and the graphite carbon plate into an electrolytic cell. The graphite carbon plate is connected to the negative terminal of the power supply, and the titanium-based coated anode plate is connected to the positive terminal of the power supply. The distance between the graphite carbon plate and the titanium-based coated anode is 10 mm.

[0053] S114. The electrolyte temperature is raised to between 50 and 55°C using a heating rod, air is introduced for stirring, and the power supply current density is set to 20A / dm³. 2 Electroplating for 1 minute forms an electrolytic copper foil on the surface of the graphite carbon plate.

[0054] S115. Remove the graphite carbon plate, rinse the surface of the electrolytic copper foil with water, dry it, and peel the electrolytic copper foil off the graphite carbon plate to obtain the following: Figure 8 The 6-micrometer carbon-coated copper foil shown.

[0055] Example 3

[0056] A method for preparing carbon-coated copper foil includes the following steps:

[0057] S121. Prepare the electrolyte, wherein Cu 2+ The concentration is 90 g / L, the H2SO4 concentration is 100 g / L, and the Cl concentration is... - The electrolyte is prepared by adding the following components to an electrolytic cell: a brightener of 10 ppm (sodium 3-mercapto-1-propanesulfonate), a leveling agent of 3 ppm (2-mercaptothiazoline), and a wetting agent of 20 ppm (a mixture of collagen, hydroxyethyl cellulose, and polyethylene glycol in a 12:1:7 ratio).

[0058] S122. Take a high-purity graphite carbon plate, polish it with 2000-grit sandpaper, and then rinse it with water.

[0059] S123. Place the titanium-based coated anode and the graphite carbon plate into an electrolytic cell. The graphite carbon plate is connected to the negative terminal of the power supply, and the titanium-based coated anode plate is connected to the positive terminal of the power supply. The distance between the graphite carbon plate and the titanium-based coated anode is 10mm.

[0060] S124. The electrolyte temperature is raised to between 50 and 55°C using a heating rod, air is introduced for stirring, and the power supply current density is set to 27A / dm³. 2 Electroplating is performed for 55 seconds to form an electrolytic copper foil on the surface of the graphite carbon plate.

[0061] S125. Remove the graphite carbon plate, rinse the surface of the electrolytic copper foil with water, dry it, and peel the electrolytic copper foil off the graphite carbon plate to obtain the following: Figure 9 The 6-micrometer carbon-coated copper foil shown.

[0062] Example 4

[0063] A method for preparing carbon-coated copper foil includes the following steps:

[0064] S131. Prepare an electrolyte solution with the following composition: Cu2+ concentration of 90 g / L, H2SO4 concentration of 100 g / L, Cl- concentration of 10 ppm, brightener of 10 ppm sodium N,N-dimethyldithiocarbamate propane sulfonate, leveling agent of 4 ppm 2-mercaptothiazoline, and wetting agent of 10 ppm a mixture of collagen, hydroxyethyl cellulose, and polyethylene glycol in a 6:1:5 ratio. Add the electrolyte solution to the electrolytic cell.

[0065] S132. Take a high-purity graphite carbon plate, polish it with 2000-grit sandpaper, and then rinse it with water.

[0066] S133. Place the titanium-based coated anode and the graphite carbon plate into an electrolytic cell. The graphite carbon plate is connected to the negative terminal of the power supply, and the titanium-based coated anode plate is connected to the positive terminal of the power supply. The distance between the graphite carbon plate and the titanium-based coated anode is 10 mm.

[0067] S134. The electrolyte temperature is raised to between 50 and 55°C by heating rod, air is blown in and stirred, the power supply current density is set to 10A / dm2, and electroplating is performed for 2 minutes to form an electrolytic copper foil on the surface of the graphite carbon plate.

[0068] S135. Take out the graphite carbon plate, rinse the surface of the electrolytic copper foil with water, dry it, and peel the electrolytic copper foil off the graphite carbon plate to obtain a 6-micron carbon-coated copper foil.

[0069] Example 5

[0070] A method for preparing carbon-coated copper foil includes the following steps:

[0071] S141. Prepare the electrolyte, wherein Cu 2+ The concentration is 90 g / L, the H2SO4 concentration is 100 g / L, and the Cl concentration is... - The electrolyte is 10 ppm, the brightener is 10 ppm sodium didithiopropane sulfonate, the leveling agent is 2 ppm 2-mercaptothiazoline, and the wetting agent is 12 ppm of collagen, hydroxyethyl cellulose, and polyethylene glycol compounded in a 6:1:5 ratio. The electrolyte is added to the electrolytic cell.

[0072] S142. Take a high-purity graphite carbon plate, polish it with 2000-grit sandpaper, and then rinse it with water.

[0073] S143. Place the titanium-based coated anode and the graphite carbon plate into an electrolytic cell. The graphite carbon plate is connected to the negative terminal of the power supply, and the titanium-based coated anode plate is connected to the positive terminal of the power supply. The distance between the graphite carbon plate and the titanium-based coated anode is 10 mm.

[0074] S144. The electrolyte temperature is raised to between 50 and 55°C by heating rod, air is blown in to stir, the power supply current density is set to 50A / dm2, and electroplating is performed for 25s to form an electrolytic copper foil on the surface of the graphite carbon plate.

[0075] S145. Remove the graphite carbon plate, rinse the surface of the electrolytic copper foil with water, dry it, and peel the electrolytic copper foil off the graphite carbon plate to obtain a 6-micron carbon-coated copper foil.

[0076] Comparative Example

[0077] A method for preparing carbon-coated copper foil includes the following steps:

[0078] S151. Prepare the electrolyte, wherein Cu 2+The concentration is 90 g / L, the H2SO4 concentration is 100 g / L, and the Cl concentration is... - The electrolyte is 10 ppm, the brightener is 10 ppm sodium didithiopropane sulfonate, the leveling agent is 5 ppm 2-mercaptothiazoline, and the wetting agent is 12 ppm of collagen, hydroxyethyl cellulose, and polyethylene glycol compounded in a 6:1:5 ratio. The electrolyte is added to the electrolytic cell.

[0079] S152. Take a high-purity graphite carbon plate, polish it with 2000-grit sandpaper, and then rinse it with water.

[0080] S153. Place the titanium-based coated anode and the graphite carbon plate into an electrolytic cell. The graphite carbon plate is connected to the negative terminal of the power supply, and the titanium-based coated anode plate is connected to the positive terminal of the power supply. The distance between the graphite carbon plate and the titanium-based coated anode is 10mm.

[0081] S154. The electrolyte temperature is raised to between 50 and 55°C using a heating rod, air is introduced for stirring, and the power supply current density is set to 20A / dm³. 2 Electroplating for 1 minute forms an electrolytic copper foil on the surface of the graphite carbon plate.

[0082] S155. Remove the graphite carbon plate and rinse the surface of the electrolytic copper foil with water. The copper foil cracks and cannot be peeled off to obtain a complete copper foil.

[0083] In summary, the method for preparing carbon-coated copper foil provided by this invention directly forms electrolytic copper foil on the surface of a graphite carbon plate through an electrochemical deposition process. This eliminates the need for complex equipment and binders required in traditional carbon coating processes, simplifying the operation, reducing process difficulty, and lowering raw material and equipment costs. It is not only easier to scale up applications but also reduces the risk of uneven coating, cracks, porosity, or delamination caused by complex operations, thereby improving product consistency and reliability. Furthermore, this method integrates the carbon coating and electrolytic copper foil production processes into a continuous step, significantly increasing the yield per unit time and shortening the production cycle compared to traditional multi-step processes.

[0084] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing carbon-coated copper foil, characterized in that: Includes the following steps: S1. A graphite carbon plate is used as the cathode and an electrolytic copper foil anode plate is used as the anode. The plates are placed in an electrolyte, which is a copper sulfate solution containing additives. S2. Electrochemical deposition is performed at a calibrated temperature and calibrated current to form an electrolytic copper foil on the surface of the graphite carbon plate; S3. After terminating the deposition, rinse the surface of the electrolytic copper foil with pure water, and then dry the electrolytic copper foil. S4. Peel the electrolytic copper foil from the graphite carbon plate to obtain the finished carbon-coated copper foil.

2. The method for preparing carbon-coated copper foil according to claim 1, characterized in that: In step S1, the electroplated surface of the graphite carbon plate is first polished with 2000-grit sandpaper and washed with water.

3. The method for preparing carbon-coated copper foil according to claim 1, characterized in that: The electrolytic copper foil anode plate is a titanium-based coated anode.

4. The method for preparing carbon-coated copper foil according to claim 1, characterized in that: The additives include brighteners, leveling agents, and wetting agents.

5. The method for preparing carbon-coated copper foil according to claim 4, characterized in that: The mass concentration ratio of the brightener, leveling agent, and wetting agent is 1:(0.2-0.4):(1-2).

6. The method for preparing carbon-coated copper foil according to claim 4, characterized in that: The brightener is an organic compound containing sodium sulfonate groups.

7. The method for preparing carbon-coated copper foil according to claim 4, characterized in that: The leveling agent is an amine organic compound.

8. The method for preparing carbon-coated copper foil according to claim 4, characterized in that: The wetting agent is one or more of collagen polymers, cellulose polymers, and polyethers.

9. The method for preparing carbon-coated copper foil according to claim 1, characterized in that: The calibration temperature is 50–55°C.

10. The method for preparing carbon-coated copper foil according to claim 1, characterized in that: The rated current is 10–50 A / dm. 2 .

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