Graphene composite copper wire and preparation method thereof

Abstract

The invention provides a graphene composite copper wire and a preparation method thereof.The preparation method of the graphene composite copper wire comprises the steps that 1, a copper base material is provided; 2, the outer surface of the copper base material is coated with graphene dispersion liquid; 3, plating copper on the outer surface of the copper wire by using an electroplating method; 4, the step 2 and the step 3 are repeated for n times, and the graphene composite copper wire is obtained; the graphene composite copper wire comprises a copper base material and a plurality of composite layers wrapping the outer surface of the copper base material, and each composite layer comprises a graphene layer and a copper layer which are sequentially arranged from inside to outside in the radial direction of the copper wire. According to the graphene composite copper wire, the copper base material is treated through the electroplating method, the multiple composite layers formed by combining the copper and the graphene are formed on the surface of the copper base material, and the graphene composite copper wire is finally obtained, so that the conductivity of the copper can be improved, the technological process is simple, too many complicated steps are not needed, the preparation condition is simple, and the cost is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper wire preparation, and in particular relates to a graphene composite copper wire and a preparation method thereof. Background Art

[0002] Graphene-composite copper wire is a novel composite material combining graphene and copper wire. Thanks to graphene's high electron mobility, thermal conductivity, and mechanical strength, graphene-composite copper wire exhibits significant improvements in electrical conductivity, thermal conductivity, and mechanical properties compared to traditional copper wire. Currently, the main methods for preparing this composite material include: 1. Vapor-phase growth on copper wire surfaces; 2. Liquid-phase growth on copper wire surfaces; 3. Die-casting and drawing of graphene-composite copper powder; and 4. Curling and drawing of graphene-composite copper foil. Each method has its advantages, but most suffer from complex processes, demanding preparation conditions, and high costs, significantly limiting the application of graphene-composite copper wire. Summary of the Invention

[0003] The technical purpose of the present invention is to provide a graphene composite copper wire and a preparation method thereof, aiming to solve the technical problems of the graphene composite copper wire in the related art, such as complex process, harsh preparation conditions and high cost.

[0004] To solve the above technical problems, the present invention is implemented as follows: a method for preparing a graphene composite copper wire, comprising: Step 1: providing a copper substrate; Step 2: coating the outer surface of the copper substrate with a graphene dispersion; Step 3: Electroplating the copper wire to form copper on the outer surface. Step 4: repeat steps 2 and 3 n times to obtain a graphene composite copper wire; The graphene composite copper wire includes a copper substrate and a plurality of composite layers coated on the outer surface of the copper substrate. Along the radial direction of the copper wire, the composite layers include graphene layers and copper layers arranged in sequence from the inside to the outside.

[0005] Furthermore, in some embodiments, step 2 includes: mixing graphene powder in different solvents to obtain graphene dispersions; Dip a piece of absorbent cotton in the graphene dispersion, wrap the absorbent cotton ball around one end of the copper wire, and pull the copper wire so that the graphene dispersion on the absorbent cotton ball is smeared on the surface of the copper wire; The copper wire coated with the graphene dispersion is placed in a vacuum drying oven and dried at 60° C. to 150° C. for 1 to 12 hours to obtain a graphene-coated copper wire.

[0006] Furthermore, in some embodiments, the solvent includes any one of acetone, N-methylpyrrolidone, and N,N-dimethylformamide.

[0007] Furthermore, in some embodiments, the graphene powder is mixed in different solvents to obtain a graphene dispersion, comprising: Inert gas was introduced into different solvents for 1 to 10 minutes to obtain deoxygenated solvents; The graphene powder is added into a deoxygenated solvent and mixed thoroughly to obtain a graphene dispersion.

[0008] Furthermore, in some embodiments, step 3 includes: Dissolve copper salt in deionized water and adjust the pH to between 1 and 6 to obtain a copper electrolyte; The graphene-coated copper wire is placed in an electrolytic cell and connected to the cathode. The anode is pure copper. At the same time, copper electrolyte is added to the electrolytic cell until the copper wire is submerged, and an electroplating process is performed to coat the graphene with copper.

[0009] Furthermore, in some embodiments, the electroplating current is between 1A and 10A, and the electroplating time is between 1 and 60 minutes.

[0010] Furthermore, in some embodiments, the thickness of the electroplating layer is between 5 and 100 microns.

[0011] Furthermore, in some embodiments, after step 4, the method further includes: Step 5: calcining the graphene composite copper wire in a vacuum furnace: placing the graphene composite copper wire in a vacuum tube furnace, repeatedly introducing inert gas, controlling the temperature at 950° C. to 1000° C., and keeping the temperature for 0.5 to 2 hours; Step 6: Use a puller to pull the calcined graphene composite copper wire to regularize the wire diameter; Step 7, annealing treatment: Place the graphene composite copper wire in step 6 in a vacuum furnace and evacuate to below 1 Pa, repeatedly introduce inert gas, control the temperature at 400° C. to 600° C., and keep warm for 10 minutes to 30 minutes.

[0012] Furthermore, in some embodiments, the wire diameter of the copper substrate is between 350 and 850 microns.

[0013] Furthermore, in some embodiments, a graphene composite copper wire is prepared using the above-mentioned preparation method, wherein the graphene composite copper wire includes a copper substrate and several composite layers coated on the outer surface of the copper substrate, and along the radial direction of the copper wire, the composite layer includes a graphene layer and a copper layer arranged sequentially from the inside to the outside.

[0014] Compared with the related art, the preparation method of the graphene composite copper wire in the present invention has the following advantages: By treating a copper substrate with an electroplating method and forming a multi-layer composite layer composed of copper and graphene on the surface of the copper substrate, a graphene composite copper wire is finally obtained. In this way, the electrical conductivity of copper can be improved. In addition, the process is simple, does not require too many complicated steps, and the preparation conditions are simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 1 is a flow chart of a method for preparing a graphene composite copper wire according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0019] See Figure 1 , an embodiment of the present invention provides a method for preparing a graphene composite copper wire, comprising: Step 1: providing a copper substrate; Step 2: coating the outer surface of the copper substrate with a graphene dispersion; Step 3: Electroplating the copper wire to form copper on the outer surface. Step 4: repeat steps 2 and 3 n times to obtain a graphene composite copper wire; The graphene composite copper wire includes a copper substrate and several composite layers coated on the outer surface of the copper substrate. Along the radial direction of the copper wire, the composite layers include graphene layers and copper layers arranged in sequence from the inside to the outside.

[0020] In an embodiment of the present invention, a copper substrate is treated by electroplating, and a multi-layer composite layer composed of copper and graphene is formed on the surface of the copper substrate, thereby finally obtaining a graphene composite copper wire. In this way, the electrical conductivity of copper can be improved. In addition, the process is simple, does not require too many complicated steps, and the preparation conditions are simple and the cost is low.

[0021] Furthermore, in some embodiments, the copper substrate may be conventional copper wire. After step 1 and before step 2, the method further includes: cleaning the copper substrate by soaking it in deionized water and ultrasonicating it for 1 to 10 minutes, removing it from the water, and ultrasonicating it again in acetone for 1 to 10 minutes. After removing it from the water, it is blown dry with high-purity nitrogen to remove surface stains and obtain a clean copper wire. The copper wire diameter is between 200 μm and 800 μm, and the ultrasonic power is 100 to 1000 W.

[0022] Furthermore, step 2, coating the outer surface of the copper substrate with a graphene dispersion, specifically comprises: Step 21, mixing graphene powder in different solvents to obtain a graphene dispersion; Step 22: Dip a piece of absorbent cotton into the graphene dispersion, wrap the absorbent cotton ball around one end of the copper wire, and pull the copper wire so that the graphene dispersion on the absorbent cotton ball is applied to the surface of the copper wire; Step 23: Place the copper wire coated with the graphene dispersion in a vacuum drying oven and dry it at 60° C. to 150° C. for 1 to 12 hours to obtain a graphene-coated copper wire.

[0023] Step 21 is a process for preparing a graphene solution, and the solvent can be acetone, N-methylpyrrolidone, or N,N-dimethylformamide. The specific process of step 21 can be: bubbling an inert gas into different solvents for 1 to 10 minutes to obtain a deoxygenated solvent; adding graphene powder to the deoxygenated solvent and thoroughly mixing to obtain a graphene dispersion.

[0024] For example, the inert gas can be argon. High-purity argon can be introduced into different solvents, and the time of introducing the inert gas can be controlled. In this way, the oxygen in the system can be reduced, thereby reducing the oxidation of copper and graphene, which is beneficial to improving the conductivity of the final product.

[0025] In addition, the graphene powder can be added to the deoxygenated solvent by ultrasound, wherein the ultrasound power is between 100W and 1000W and the ultrasound time is between 0.5 and 8 hours.

[0026] Specifically, different ultrasonic powers and ultrasonic times can be determined according to the different solvents in step 21; when acetone solvent is used, the corresponding ultrasonic power can be relatively high and the ultrasonic time can be relatively long; and when N-methylpyrrolidone or N,N-dimethylformamide is used, the corresponding ultrasonic power can be relatively small and the ultrasonic time can be relatively short. In this way, the graphene dispersion can be fully ultrasonicated through the combination of solvent, ultrasonic power and ultrasonic time, thereby improving the conductivity of the final product.

[0027] Furthermore, the concentration of the graphene dispersion can be between 0.2 mg / ml and 10 mg / ml. By limiting the concentration range of the graphene dispersion, it can be ensured that the graphene dispersion can be well wrapped around the outer surface of the copper wire to form a graphene layer, and the conductivity of the final product can also be improved. In addition, depending on the desired concentration of the graphene dispersion, during the ultrasonic process of adding the deoxygenated solvent to the graphene powder, the ultrasonic power and ultrasonic time can be further adjusted within a corresponding range, thereby further improving the uniformity of the graphene dispersion and further improving the conductivity of the final product.

[0028] Step 22: Dip the graphene dispersion liquid into a cotton ball, wrap the cotton ball around one end of the copper wire, and pull the copper wire so that the graphene dispersion liquid on the cotton ball is smeared on the surface of the copper wire.

[0029] Specifically, the absorbent cotton ball can be slightly dipped in the graphene dispersion. During the process of pulling the copper wire, slight pressure can be applied to the absorbent cotton ball so that the absorbent cotton ball can tightly wrap the copper wire but the soaked graphene dispersion does not drip. In this way, the graphene dispersion on the absorbent cotton ball can be evenly applied to the surface of the copper wire, eventually forming a uniform graphene layer.

[0030] Step 23: Place the copper wire coated with the graphene dispersion in a vacuum drying oven and dry it at 60° C. to 150° C. for 1 to 12 hours to obtain a graphene-coated copper wire.

[0031] Specifically, different drying temperatures and drying times can be determined according to the different solvents in step 21. Among them, acetone can correspond to a lower drying temperature and a shorter drying time, and N-methylpyrrolidone and N,N-dimethylformamide can correspond to a higher drying temperature and a longer drying time. Through the combination of solvent, drying temperature and drying time, the conductivity can be significantly improved.

[0032] Furthermore, step 3, using an electroplating method to plate copper on the outer surface of the copper wire, specifically includes: Step 31, dissolving copper salt in deionized water and adjusting the pH to between 1 and 6 to obtain a copper electrolyte; Step 32: Place the copper wire coated with graphene in an electrolytic cell and connect it to the cathode. The anode is pure copper. At the same time, add copper electrolyte to the electrolytic cell until the copper wire is submerged, and perform an electroplating process to coat the graphene with copper.

[0033] Step 31 is the preparation process of a copper electrolyte. Specifically, the copper salt can be copper sulfate, copper chloride, or copper acetate. A high-purity copper salt can be dissolved in deionized water, and a small amount of concentrated hydrochloric acid is added and stirred thoroughly to obtain a copper electrolyte. The electrolyte concentration can be controlled between 1 mg / ml and a saturated solution, and the pH value is controlled between 1 and 6. This is conducive to the full implementation of the electroplating process, so that the copper can be well coated on the outer surface of the graphene layer.

[0034] In addition, step 32 is a specific electroplating process. Specifically, the graphene-coated copper wire can be placed in an electrolytic cell, wherein the cathode of a constant current power supply can be connected to the copper wire, a pure copper rod is additionally used as an anode, and a copper electrolyte is added to the electrolytic cell, thus forming an electroplating system. After the constant current power supply is turned on, the electroplating process can begin, and a copper layer can eventually be electroplated on the outer surface of the graphene layer.

[0035] Furthermore, the electroplating current can be controlled between 1A and 10A, and the electroplating time can be controlled between 1 and 60 minutes. By controlling the current and the electroplating time, the thickness of the electroplated layer can be controlled between 5 and 100 microns, that is, a copper layer of 5 to 100 microns can be obtained, specifically 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 microns, etc., which can reflect the different glossiness of the copper surface, allowing the copper layer to be well wrapped around the outer surface of the graphene layer. The synergy between the copper layer and the graphene layer can also improve the conductivity of the final product.

[0036] In addition, in the embodiment of the present invention, the copper and graphene are composited by applying graphene on the copper wire and then plating copper on the graphene, which is simple to operate and low in cost. Moreover, the embodiment of the present invention is improved on the basis of conventional copper wire, so compared with conventional copper wire, the electrical conductivity can be significantly improved. Compared with conventional composite copper wire, it can not only further simplify the operation steps and reduce costs, but also improve the electrical conductivity of the final product through the synergy of the graphene layer and the copper layer.

[0037] Furthermore, in step 3, after copper electroplating, the copper wire can be removed from the electrolytic bath and repeatedly rinsed in deionized water several times until the electrolyte is completely removed. Cleanliness is determined by measuring the conductivity of the cleaning solution. When the conductivity of the cleaning solution is 2 microsiemens / cm or less, which is close to the conductivity of deionized water, it indicates that there is no residual electrolyte on the outer surface of the copper wire.

[0038] It should be noted that each time after step 3, a cleaning process must be performed to effectively prevent the electrolyte from affecting the conductivity.

[0039] For step 4, repeat steps 2 and 3 n times to obtain the graphene composite copper wire.

[0040] Specifically, n can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and so on. Step 2 involves applying a graphene dispersion to form a graphene layer, and step 3 involves plating a copper layer. Each time step 2 and step 3 are repeated, a composite layer is formed on the outer surface of the copper wire. Repeating steps 2 and 3 multiple times can create a multi-layer composite layer, further improving conductivity. Furthermore, due to the coordination of the thickness of the graphene and copper layers, the conductivity of the final product can be significantly improved.

[0041] Furthermore, after step 4, the method further includes: Step 5: calcining the graphene composite copper wire in a vacuum furnace: placing the graphene composite copper wire in a vacuum tube furnace, repeatedly introducing inert gas, controlling the temperature at 950° C. to 1000° C., and keeping the temperature for 0.5 to 2 hours; Step 6: Use a puller to pull the calcined graphene composite copper wire to regularize the wire diameter; Step 7, annealing treatment: Place the graphene composite copper wire in step 6 in a vacuum tube furnace and evacuate to below 1 Pa, repeatedly introduce inert gas, control the temperature at 400° C. to 600° C., and keep warm for 10 minutes to 30 minutes.

[0042] Specifically, after obtaining the graphene composite copper wire, it can be calcined in a vacuum furnace, then drawn to regularize the wire diameter, and finally annealed to obtain the final product.

[0043] For step 5, first place the graphene in a vacuum furnace and evacuate it to below 1 Pa. Then, introduce a high-purity inert gas, such as argon, and repeat this process three times to dilute the oxygen concentration. Finally, introduce high-purity argon until the vacuum furnace pressure is slightly less than 1 standard atmospheric pressure. Meanwhile, control the temperature between 950°C and 1000°C. The expanding air at this temperature maintains a positive pressure in the vacuum furnace. Maintain the temperature for 0.5 to 2 hours, then turn off the power and allow the temperature to naturally cool to room temperature. Calcination promotes contact between graphene and copper, maintaining electrical conductivity.

[0044] In addition, step 6 is mainly used to measure the graphene composite copper wire obtained in step 5. The wire diameter of the graphene composite copper wire can be measured multiple times and the minimum value is taken. Then, according to the minimum value, a puller with a wire diameter smaller than the minimum value is selected for pulling. In this way, there is resistance to pulling the graphene composite copper wire, and the graphene composite copper wire can be regularized. In addition, the thickness of the composite layer is much smaller than the wire diameter of the copper substrate. Therefore, for copper substrates with the same wire diameter, even if the wire diameter of the final graphene composite copper wire is slightly different due to slight differences in electroplating time, the same specification of puller can be selected for pulling, thereby obtaining a variety of graphene composite copper wires with uniform wire diameters.

[0045] For step 7: Place the graphene composite copper wire of step 6 in a vacuum tube furnace and evacuate to below 1 Pa, introduce high-purity argon gas to 1 standard atmospheric pressure, repeat 3 times to dilute the oxygen concentration, and finally introduce high-purity argon gas to slightly less than 1 standard atmospheric pressure. Control the temperature at 400°C to 600°C. The expanded air at this temperature always maintains a positive pressure in the vacuum furnace. Keep warm for 10 minutes to 30 minutes for annealing. Then turn off the power and wait for the temperature to naturally drop to room temperature before taking out the graphene composite copper wire to obtain the final product.

[0046] Furthermore, in some embodiments, the wire diameter of the copper substrate is between 350 and 850 microns.

[0047] Specifically, the wire diameter of the copper substrate can be 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850 microns, etc. The wire diameter of the copper substrate is between 350 and 850 microns, so that the composite layer can cooperate well with the copper substrate, give full play to the role of the composite layer, and ensure electrical conductivity.

[0048] Furthermore, a graphene composite copper wire is prepared using a preparation method. The graphene composite copper wire includes a copper substrate and several composite layers coated on the outer surface of the copper substrate. Along the radial direction of the copper wire, the composite layer includes a graphene layer and a copper layer arranged in sequence from the inside to the outside.

[0049] In an embodiment of the present invention, a copper substrate is treated by electroplating, and a multi-layer composite layer composed of copper and graphene is formed on the surface of the copper substrate, ultimately obtaining a graphene composite copper wire. In this way, the electrical conductivity of copper can be improved. In addition, the process is simple, does not require too many complicated steps, and the preparation conditions are simple and the cost is low.

[0050] The following is further described by way of examples. It should be understood that the specific examples described herein are only used to explain the present invention, rather than to limit the present invention.

[0051] First implementation of Example 1 Step 1: Soak a regular copper wire (wire diameter 400 microns) in deionized water and ultrasonicate for 10 minutes. After taking it out, transfer it to acetone and ultrasonicate it again for 10 minutes. After taking it out, blow it dry with high-purity nitrogen to remove surface stains and obtain a clean copper wire.

[0052] Step 2: Add conventional graphene powder to deoxygenated acetone and thoroughly sonicate to obtain a 3mg / ml graphene dispersion at 1000W for 5 hours. Dip a cotton ball into the graphene dispersion and wrap it around one end of a clean copper wire. Pull the wire while applying slight pressure to the cotton ball to evenly apply the graphene dispersion to the surface. Place the copper wire in a vacuum drying oven at 60°C for 1 hour to remove the solvent, yielding the graphene-coated copper wire.

[0053] Step 3: Place the graphene-coated copper wire in an electroplating tank and connect it to the cathode of a constant current power supply. The anode is a high-purity copper rod. Add electrolyte to the electrolytic tank until the copper wire is submerged. The electrolyte is prepared from copper sulfate with a pH value of about 2 and a concentration of 120 mg / ml. Turn on the constant current power supply with a current of 1A and an electroplating time of 7 minutes to obtain a graphene composite copper wire having a layer of graphene and a layer of copper. Remove the copper wire obtained above from the electrolytic tank and place it in deionized water and wash it repeatedly several times until the electrolyte is completely washed away. Confirm whether it is clean by measuring the conductivity of the cleaning solution, which is required to be 2 microsiemens / cm or less, that is, close to the conductivity of deionized water.

[0054] Step 4: Repeat steps 2 and 3 for a total of 3 times to obtain a graphene composite copper wire with three composite layers.

[0055] Step 5: Place the three-layer graphene-composite copper wire in a vacuum tube furnace and evacuate to below 1 Pa. High-purity argon is introduced to 1 standard atmosphere, and the oxygen concentration is diluted three times. Finally, high-purity argon is introduced to slightly below 1 standard atmosphere. The temperature is controlled at 950°C. The expanded air at this temperature maintains a positive pressure in the vacuum furnace. The furnace is kept at this temperature for 1 hour, then the power is turned off and the temperature is allowed to cool naturally to room temperature before the graphene-composite copper wire is removed.

[0056] Step 6: The diameter of the graphene composite copper wire is measured to be approximately 428 μm. A 425 μm aperture puller is selected for pulling to regularize the graphene composite copper wire to obtain a graphene composite copper wire with uniform wire diameter.

[0057] Step 7: Place the above-mentioned graphene composite copper wire in a vacuum tube furnace and evacuate it to below 1 Pa, introduce high-purity argon gas to 1 standard atmospheric pressure, repeat 3 times to dilute the oxygen concentration, and finally introduce high-purity argon gas to slightly below 1 standard atmospheric pressure. Control the temperature at 600°C. The expanded air at this temperature always maintains a positive pressure in the vacuum furnace. Keep warm for 20 minutes for annealing. Then turn off the power and wait for the temperature to naturally drop to room temperature before taking out the graphene composite copper wire to obtain the final product.

[0058] The second implementation method of Example 1; compared with the first implementation method of Example 1, it only includes steps one to three, and steps five to seven, and the final product is a graphene composite copper wire having a composite layer; wherein, in step three, the electroplating time is modified to 20 minutes, so that the electroplating time in the second implementation method is approximately the same as the sum of the electroplating times of the three electroplating times in the first implementation method, so that the wire diameter of the graphene composite copper wire obtained in the second implementation method is approximately the same as the wire diameter of the graphene composite copper wire obtained in the first implementation method. Thus, the wire diameter of the graphene composite copper wire measured in the second implementation method is approximately 428 microns, and a 425-micron aperture puller can be selected for drawing.

[0059] Third implementation of Example 1: Compared with the first implementation of Example 1, step 4 is modified to repeat step 2 and step 3 a total of 2 times to obtain a graphene composite copper wire having two composite layers, and the other steps remain unchanged; wherein, the electroplating time in step 3 is changed to 10 minutes, that is, the single electroplating time is 10 minutes, so that the sum of the 2 electroplating times in the third implementation is approximately the same as the sum of the electroplating times of the 3 electroplating times in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the third implementation is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation. Thus, the wire diameter of the graphene composite copper wire measured in the third implementation is approximately 426 microns, and a 425-micron aperture puller can be selected for drawing.

[0060] Fourth implementation method of Example 1: Compared with the first implementation method of Example 1, step 4 is modified to repeat step 2 and step 3 a total of 5 times to obtain a graphene composite copper wire having five composite layers, and the other steps remain unchanged; wherein, the electroplating time for the electroplating in step 3 is changed to 4 minutes, that is, the single electroplating time is 4 minutes, so that the sum of the 5 electroplating times in the fourth implementation method is approximately the same as the sum of the electroplating times of the 3 electroplating times in the first implementation method, so that the wire diameter of the graphene composite copper wire obtained in the third implementation method is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation method. Thus, the wire diameter of the graphene composite copper wire measured in the third implementation method is approximately 431 microns, and a 425-micron aperture puller can be selected for drawing.

[0061] Comparative Example 1: Compared with Example 1, only the copper wire of step 1 is included.

[0062] First implementation of Example 2 Step 1: Soak a regular copper wire (wire diameter 600 microns) in deionized water and ultrasonicate for 10 minutes. After taking it out, transfer it to acetone and ultrasonicate it again for 10 minutes. After taking it out, blow it dry with high-purity nitrogen to remove surface stains and obtain a clean copper wire.

[0063] Step 2: Add conventional graphene powder to deoxygenated N,N-dimethylformamide and thoroughly sonicate to obtain a graphene dispersion with a concentration of 4.5 mg / ml. The ultrasonic power is 800 W and the sonication time is 2 hours. Dip a cotton ball into the graphene dispersion and wrap the cotton ball around one end of a clean copper wire. Pull the copper wire and apply slight pressure to the cotton ball to evenly apply the graphene dispersion to the surface of the copper wire. Place the copper wire in a vacuum drying oven and dry it at 150°C for 12 hours to remove the solvent, obtaining a graphene-coated copper wire.

[0064] Step 3: Place the graphene-coated copper wire in an electroplating tank connected to the cathode of a constant current power supply. The anode is a high-purity copper rod. Add electrolyte to the electrolytic tank until the copper wire is submerged. The electrolyte is prepared by copper chloride with a pH value of about 2 and a concentration of 130 mg / ml. Turn on the constant current power supply with a current of 2A and an electroplating time of 6 minutes to obtain a graphene composite copper wire having a layer of graphene and a layer of copper. Remove the graphene composite copper wire from the electrolytic tank and place it in deionized water for repeated cleaning several times until the electrolyte is completely washed away. Confirm whether it is clean by measuring the conductivity of the cleaning solution, which is required to be 2 microsiemens / cm or less, that is, close to the conductivity of deionized water.

[0065] Step 4: Repeat steps 2 and 3 for a total of 5 times to obtain a graphene composite copper wire with five composite layers.

[0066] Step 5: Place the graphene-composite copper wire in a vacuum tube furnace, evacuate to below 1 Pa, introduce high-purity argon gas to 1 standard atmosphere, repeat this process three times to dilute the oxygen concentration, and finally introduce high-purity argon gas to slightly below 1 standard atmosphere. The temperature is controlled at 1000°C. The expanded air at this temperature maintains a positive pressure in the vacuum furnace. Keep the temperature for 1 hour, then turn off the power and allow the temperature to naturally cool to room temperature before removing the graphene-composite copper wire.

[0067] Step 6: The diameter of the graphene composite copper wire is measured to be about 655 microns. A 650-micron aperture puller is selected for pulling to regularize the graphene composite copper wire to obtain a graphene composite copper wire with uniform wire diameter.

[0068] Step 7: Place the above-mentioned graphene composite copper wire in a vacuum tube furnace and evacuate it to below 1 Pa, introduce high-purity argon gas to 1 standard atmospheric pressure, repeat 3 times to dilute the oxygen concentration, and finally introduce high-purity argon gas to slightly below 1 standard atmospheric pressure. Control the temperature at 600°C. The expanded air at this temperature always maintains a positive pressure in the vacuum furnace. Keep warm for 20 minutes for annealing. Then turn off the power and wait for the temperature to naturally drop to room temperature before taking out the graphene composite copper wire to obtain the final product.

[0069] The second implementation method of Example 2; compared with the first implementation method of Example 2, it only includes steps one to three, and steps five to seven, and the final product is a graphene composite copper wire having a composite layer; wherein, in step three, the electroplating time is modified to 31 minutes, so that the electroplating time in the second implementation method is approximately the same as the sum of the electroplating times of the five electroplating times in the first implementation method, so that the wire diameter of the graphene composite copper wire obtained in the second implementation method is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation method, so that the wire diameter of the graphene composite copper wire measured in the second implementation method is approximately 653 microns, and a 650-micron aperture puller can be selected for drawing.

[0070] The third implementation method of Example 2: Compared with the first implementation method of Example 2, step 4 is modified to repeat step 2 and step 3 a total of 2 times to obtain a graphene composite copper wire having two composite layers, and the other steps remain unchanged; wherein, in step 3, the electroplating time is modified to 16 minutes, that is, the single electroplating time is 16 minutes, so that the sum of the electroplating times of the 2 electroplating times in the third implementation is approximately the same as the sum of the electroplating times of the 5 electroplating times in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the third implementation is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation. Thus, the wire diameter of the graphene composite copper wire measured in the third implementation is approximately 657 microns, and a 650-micron aperture puller can be selected for drawing.

[0071] Fourth implementation method of Example 2: Compared with the first implementation method of Example 2, step 4 is modified to repeat step 2 and step 3 a total of 3 times to obtain a graphene composite copper wire having three composite layers, and the other steps remain unchanged; wherein, in step 3, the electroplating time is modified to 10 minutes, that is, the single electroplating time is 10 minutes, so that the sum of the electroplating times of the 3 electroplating times in the fourth implementation is approximately the same as the sum of the electroplating times of the 5 electroplating times in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the fourth implementation is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation. Thus, the wire diameter of the graphene composite copper wire measured in the fourth implementation is approximately 660 microns, and a 650-micron aperture puller can be selected for drawing.

[0072] Comparative Example 2: Compared with Example 2, only the copper wire of step 1 is included.

[0073] First implementation of Example 3 Step 1: Soak a regular copper wire (wire diameter 800 microns) in deionized water and ultrasonicate for 10 minutes. After taking it out, transfer it to acetone and ultrasonicate it again for 10 minutes. After taking it out, blow it dry with high-purity nitrogen to remove surface stains and obtain a clean copper wire.

[0074] Step 2: Add conventional graphene powder to deoxygenated N,N-dimethylformamide and thoroughly sonicate to obtain a graphene dispersion with a concentration of 6 mg / ml. The ultrasonic power is 800 W and the sonication time is 2 hours. Dip a cotton ball into the graphene dispersion and wrap it around one end of a clean copper wire. Pull the copper wire and apply slight pressure to the cotton ball to evenly apply the graphene dispersion to the surface of the copper wire. Place the copper wire in a vacuum drying oven and dry it at 150°C for 12 hours to remove the solvent, obtaining a graphene-coated copper wire.

[0075] Step 3: Place the graphene-coated copper wire in an electroplating tank connected to the cathode of a constant current power supply. The anode is a high-purity copper rod. Add electrolyte to the electrolytic tank until the copper wire is submerged. The electrolyte is prepared by copper chloride with a pH value of about 1 and a concentration of 140 mg / ml. Turn on the constant current power supply with a current of 3A and an electroplating time of 5 minutes to obtain a graphene composite copper wire having a layer of graphene and a layer of copper. Remove the graphene composite copper wire from the electrolytic tank and place it in deionized water for repeated cleaning several times until the electrolyte is completely washed away. Confirm whether it is clean by measuring the conductivity of the cleaning solution, which is required to be 2 microsiemens / cm or less, that is, close to the conductivity of deionized water.

[0076] Step 4: Repeat steps 2 and 3 for a total of 5 times to obtain a graphene composite copper wire with five composite layers.

[0077] Step 5: Place the graphene-composite copper wire in a vacuum tube furnace, evacuate to below 1 Pa, introduce high-purity argon gas to 1 standard atmosphere, repeat this process three times to dilute the oxygen concentration, and finally introduce high-purity argon gas to slightly below 1 standard atmosphere. The temperature is controlled at 1000°C. The expanded air at this temperature maintains a positive pressure in the vacuum furnace. Keep the temperature for 1 hour, then turn off the power and allow the temperature to naturally cool to room temperature before removing the graphene-composite copper wire.

[0078] Step 6: The diameter of the graphene composite copper wire is measured to be about 855 microns. A puller with an aperture of 850 microns is selected for drawing to regularize the graphene composite copper wire to obtain a graphene composite copper wire with uniform wire diameter.

[0079] Step 7: Place the above-mentioned graphene composite copper wire in a vacuum tube furnace and evacuate it to below 1 Pa, introduce high-purity argon gas to 1 standard atmospheric pressure, repeat 3 times to dilute the oxygen concentration, and finally introduce high-purity argon gas to slightly below 1 standard atmospheric pressure. Control the temperature at 600°C. The expanded air at this temperature always maintains a positive pressure in the vacuum furnace. Keep warm for 20 minutes for annealing. Then turn off the power and wait for the temperature to naturally drop to room temperature before taking out the graphene composite copper wire to obtain the final product.

[0080] The second implementation method of Example 3; compared with the first implementation method of Example 3, it only includes steps one to three, and steps five to seven, and the final product is a graphene composite copper wire having a composite layer; wherein, in step three, the electroplating time is modified to 26 minutes, so that the electroplating time in the second implementation method is approximately the same as the sum of the electroplating times of the five electroplating times in the first implementation method, so that the wire diameter of the graphene composite copper wire obtained in the second implementation method is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation method, so that the wire diameter of the graphene composite copper wire measured in the second implementation method is approximately 857 microns, and an 850-micron aperture puller can be selected for drawing.

[0081] A third implementation of Example 3: Compared with the first implementation of Example 3, step 4 is modified to repeat step 2 and step 3 a total of 2 times to obtain a graphene composite copper wire having two composite layers, and the other steps remain unchanged; wherein, in step 3, the electroplating time is modified to 13 minutes, that is, the single electroplating time is 13 minutes, so that the sum of the electroplating times of the 2 electroplating times in the third implementation is approximately the same as the sum of the electroplating times of the 5 electroplating times in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the third implementation is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation. Thus, the wire diameter of the graphene composite copper wire measured in the third implementation is approximately 854 microns, and an 850-micron aperture puller can be selected for drawing.

[0082] Fourth implementation of Example 3: Compared with the first implementation of Example 3, step 4 is modified to repeat step 2 and step 3 a total of 3 times to obtain a graphene composite copper wire having three composite layers, and the other steps remain unchanged; wherein, in step 3, the electroplating time is modified to 8 minutes, that is, the single electroplating time is 8 minutes, so that the sum of the electroplating times of the 3 electroplating times in the fourth implementation is approximately the same as the sum of the electroplating times of the 5 electroplating times in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the fourth implementation is similar to the wire diameter of the graphene composite copper wire obtained in the first implementation. Thus, the wire diameter of the graphene composite copper wire measured in the fourth implementation is approximately 856 microns, and an 850-micron aperture puller can be selected for drawing.

[0083] Comparative Example 3: Compared with Example 3, only the copper wire of step 1 is included.

[0084] Conductivity measurements were performed on each comparative example and each implementation of each embodiment to obtain the results in the following table.

[0085]

[0086] The test data in the table demonstrates that the electrical conductivity of the graphene composite layer in the embodiments of the present invention is significantly higher than that of conventional copper wire. Furthermore, for different implementations of the same embodiment, the electroplating time varies only slightly, and the graphene composite copper wires in each implementation are uniformly drawn using a puller of the same specification, resulting in consistent wire diameters across all implementations. The test results in the table demonstrate that the more composite layers, the higher the electrical conductivity.

[0087] It should be noted that the “wire diameter of the graphene composite copper wire in each implementation is consistent” can be understood as the “thickness of the conductive layer” in each implementation is the same, that is, in the same embodiment, whether it is one composite layer or five composite layers, the wire diameter of the obtained graphene composite copper wire is the same. It does not simply mean that the more “conductive layers” on the periphery of the copper wire make the conductivity high, but when the “conductor layer thickness” is the same, the conductivity is high due to the more composite times. That is, in addition to the presence of the composite layer on the periphery of the copper wire affecting the conductivity, the mutual cooperation between the multiple composite layers can also significantly improve the conductivity.

Claims

1. A method for preparing a graphene composite copper wire, characterized in that: include: Step 1: providing a copper substrate; Step 2: coating the outer surface of the copper substrate with a graphene dispersion; Step 3: Electroplating the copper wire to form copper on the outer surface. Step 4: repeat steps 2 and 3 n times to obtain a graphene composite copper wire; The graphene composite copper wire includes a copper substrate and a plurality of composite layers coated on the outer surface of the copper substrate. Along the radial direction of the copper wire, the composite layers include graphene layers and copper layers arranged in sequence from the inside to the outside.

2. The method for preparing the graphene composite copper wire according to claim 1, wherein: The step 2 includes: mixing graphene powder in different solvents to obtain graphene dispersions; Dip a piece of absorbent cotton in the graphene dispersion, wrap the absorbent cotton ball around one end of the copper wire, and pull the copper wire so that the graphene dispersion on the absorbent cotton ball is smeared on the surface of the copper wire; The copper wire coated with the graphene dispersion is placed in a vacuum drying oven and dried at 60° C. to 150° C. for 1 to 12 hours to obtain a graphene-coated copper wire.

3. The method for preparing the graphene composite copper wire according to claim 2, wherein: The solvent includes any one of acetone, N-methylpyrrolidone, and N,N-dimethylformamide.

4. The method for preparing the graphene composite copper wire according to claim 2, wherein: Graphene powder is mixed in different solvents to obtain a graphene dispersion, including: Inert gas was introduced into different solvents for 1 to 10 minutes to obtain deoxygenated solvents; The graphene powder is added into a deoxygenated solvent and mixed thoroughly to obtain a graphene dispersion.

5. The method for preparing the graphene composite copper wire according to claim 1, wherein: The step 3 comprises: Dissolve copper salt in deionized water and adjust the pH to between 1 and 6 to obtain a copper electrolyte; The graphene-coated copper wire is placed in an electrolytic cell and connected to the cathode. The anode is pure copper. At the same time, copper electrolyte is added to the electrolytic cell until the copper wire is submerged, and an electroplating process is performed to coat the graphene with copper.

6. The method for preparing the graphene composite copper wire according to claim 1, wherein: The electroplating current is between 1A and 10A, and the electroplating time is 1 to 60 minutes.

7. The method for preparing the graphene composite copper wire according to claim 6, wherein: The thickness of the electroplating layer is between 5 and 100 microns.

8. The method for preparing the graphene composite copper wire according to claim 1, wherein: After step 4, also include: Step 5: calcining the graphene composite copper wire in a vacuum furnace: placing the graphene composite copper wire in a vacuum tube furnace, repeatedly introducing inert gas, controlling the temperature at 950° C. to 1000° C., and keeping the temperature for 0.5 to 2 hours; Step 6: Use a puller to pull the calcined graphene composite copper wire to regularize the wire diameter; Step 7, annealing treatment: Place the graphene composite copper wire in step 6 in a vacuum tube furnace and evacuate to below 1 Pa, repeatedly introduce inert gas, control the temperature at 400° C. to 600° C., and keep warm for 10 minutes to 30 minutes.

9. The method for preparing the graphene composite copper wire according to claim 1, wherein: The copper substrate has a wire diameter between 350 and 850 microns.

10. A graphene composite copper wire, characterized in that: The graphene composite copper wire is prepared using the preparation method described in claims 1 to 9, and includes a copper substrate and several composite layers coated on the outer surface of the copper substrate. Along the radial direction of the copper wire, the composite layer includes a graphene layer and a copper layer arranged in sequence from the inside to the outside.

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