Graphene composite copper wire and preparation method thereof

Abstract

The application provides a graphene composite copper wire and a preparation method thereof. The preparation method of the graphene composite copper wire comprises the following steps: step 1, providing a copper base material; step 2, coating a graphene dispersion liquid on the outer surface of the copper base material; step 3, plating copper on the outer surface of the copper wire by using an electroplating method; and step 4, repeating steps 2 and 3 for n times to obtain the graphene composite copper wire. The graphene composite copper wire comprises the copper base material and a plurality of composite layers coated on the outer surface of the copper base material. Along the radial direction of the copper wire, the composite layers comprise graphene layers and copper layers arranged in sequence from the inside to the outside. The copper base material is treated by using the electroplating method, and a plurality of composite layers composed of copper and graphene are formed on the surface of the copper base material, so that the graphene composite copper wire is finally obtained. In this way, the electrical conductivity of copper can be improved, the process is simple, a plurality of complicated steps are not required, the preparation conditions are simple, and the cost is low.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of copper wire preparation, and particularly relates to a graphene composite copper wire and a preparation method thereof. BACKGROUND

[0002] The graphene composite copper wire is a new composite material composed of graphene and copper wire. Benefiting from the high electron mobility, high thermal conductivity and mechanical strength of graphene, the graphene composite copper wire after being combined with copper has significant improvement in electrical conductivity, thermal conductivity and mechanical properties compared with traditional copper wire. At present, the methods for preparing the composite material mainly include: 1. copper wire surface vapor phase growth method; 2. copper wire surface liquid phase growth method; 3. graphene composite copper powder compression casting and drawing method; and 4. graphene composite copper foil curling and drawing method. Each method has its own advantages, but most of them have the disadvantages of complex process, harsh preparation conditions and high cost, which greatly limits the application of the graphene composite copper wire. SUMMARY

[0003] The technical purpose of the application is to provide a graphene composite copper wire and a preparation method thereof, and aims 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 application is implemented as follows: a preparation method of a graphene composite copper wire, comprising:

[0005] Step 1, providing a copper base material;

[0006] Step 2, coating graphene dispersion liquid on the outer surface of the copper base material;

[0007] Step 3, plating copper on the outer surface of the copper wire by using an electroplating method;

[0008] Step 4, repeating steps 2 and 3 for n times to obtain the graphene composite copper wire;

[0009] The graphene composite copper wire comprises a copper base material and a plurality of composite layers wrapped on the outer surface of the copper base material, and along the radial direction of the copper wire, the composite layers comprise graphene layers and copper layers arranged in sequence from inside to outside.

[0010] Further, in some embodiments, the step 2 comprises:

[0011] mixing graphene powder in different solvents to obtain graphene dispersion liquid;

[0012] dipping the graphene dispersion liquid with absorbent cotton, wrapping the absorbent cotton around one end of the copper wire, and pulling the copper wire so that the graphene dispersion liquid on the absorbent cotton is applied to the surface of the copper wire;

[0013] The copper wire coated with the graphene dispersion liquid is placed in a vacuum drying oven and dried at 60-150°C for 1-12 hours to obtain graphene-coated copper wire.

[0014] Further, in some embodiments, the solvent includes any one of acetone, N-methyl pyrrolidone, N,N-dimethylformamide.

[0015] Further, in some embodiments, the graphene powder is mixed in different solvents to obtain a graphene dispersion liquid, including:

[0016] Inert gas is introduced into the different solvents for 1-10 minutes to obtain deoxygenated solvents;

[0017] The graphene powder is added to the deoxygenated solvents and mixed thoroughly to obtain a graphene dispersion liquid.

[0018] Further, in some embodiments, the step 3 includes:

[0019] The copper salt is dissolved in deionized water, and the pH is adjusted to 1-6 to obtain a copper electrolyte;

[0020] The graphene-coated copper wire is placed in an electrolytic cell and connected to the cathode, and the anode is pure copper. At the same time, the copper electrolyte is added to the electrolytic cell until the copper wire is submerged, and the electroplating process is carried out to coat copper outside the graphene.

[0021] Further, in some embodiments, the electroplating current is between 1A and 10A, and the electroplating time is 1-60 minutes.

[0022] Further, in some embodiments, the thickness of the electroplating layer is between 5 and 100 microns.

[0023] Further, in some embodiments, after step 4, it further includes:

[0024] Step 5, calcining the graphene composite copper wire in a vacuum furnace: the graphene composite copper wire is placed in a vacuum tube furnace, inert gas is introduced repeatedly for multiple times, the temperature is controlled at 950-1000°C, and the temperature is maintained for 0.5-2 hours.

[0025] Step 6, using a drawing device to draw the graphene composite copper wire after calcination to regularize the wire diameter;

[0026] Step 7, annealing treatment: the graphene composite copper wire of step 6 is placed in a vacuum furnace and vacuumed to below 1 Pa, inert gas is introduced repeatedly for multiple times, the temperature is controlled at 400-600°C, and the temperature is maintained for 10-30 minutes.

[0027] Further, in some embodiments, the wire diameter of the copper substrate is between 350 and 850 microns.

[0028] Further, in some embodiments, a graphene composite copper wire is prepared by using the above preparation method, the graphene composite copper wire comprises a copper substrate and a plurality of composite layers coated on the outer surface of the copper substrate, and the composite layers comprise graphene layers and copper layers arranged in sequence from inside to outside along the radial direction of the copper wire.

[0029] Compared with the related art, the graphene composite copper wire preparation method has the following beneficial effects:

[0030] By using the electroplating method to process the copper substrate and form the composite layers composed of copper and graphene on the surface of the copper substrate, the graphene composite copper wire is finally obtained, so that the electrical conductivity of copper can be improved, the process is simple, and there is no need for too many complicated steps, and the preparation conditions are simple and the cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0032] Figure 1 is a flowchart of the preparation method of the graphene composite copper wire in the embodiments of the present application. DETAILED DESCRIPTION

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "circumferential", "radial" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0034] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0035] Please refer to Figure 1The embodiment of the present application provides a preparation method of graphene composite copper wire, comprising the following steps:

[0036] Step 1, providing a copper base material;

[0037] Step 2, coating graphene dispersion liquid on the outer surface of the copper base material;

[0038] Step 3, plating copper on the outer surface of the copper wire by using an electroplating method;

[0039] Step 4, repeating steps 2 and 3 for n times to obtain the graphene composite copper wire.

[0040] The graphene composite copper wire comprises a copper base material and a plurality of composite layers wrapped on the outer surface of the copper base material, and along the radial direction of the copper wire, the composite layers comprise graphene layers and copper layers arranged in sequence from inside to outside.

[0041] In the embodiment of the present application, the copper base material is treated by using the electroplating method, and a plurality of composite layers composed of copper and graphene are formed on the surface of the copper base material, and finally the graphene composite copper wire is obtained. In this way, the electrical conductivity of copper can be improved, and the process is simple, without too many complicated steps, and the preparation conditions are simple and the cost is low.

[0042] Further, in some embodiments, the copper base material can be a conventional copper wire, and after step 1 and before step 2, the method further comprises: cleaning the copper base material; soaking the copper base material in deionized water for 1-10 minutes, taking it out and then soaking it in acetone again for 1-10 minutes, taking it out and blowing it dry with high-purity nitrogen, removing the surface stains to obtain a clean copper wire. The diameter of the copper wire is between 200 microns and 800 microns, and the ultrasonic power is 100-1000W.

[0043] Further, step 2, coating graphene dispersion liquid on the outer surface of the copper base material, specifically comprises:

[0044] Step 21, mixing graphene powder in different solvents to obtain graphene dispersion liquid;

[0045] Step 22, using absorbent cotton to dip the graphene dispersion liquid, wrapping the absorbent cotton around one end of the copper wire, and pulling the copper wire so that the graphene dispersion liquid on the absorbent cotton is applied to the surface of the copper wire;

[0046] Step 23, placing the copper wire coated with the graphene dispersion liquid in a vacuum drying oven and drying at 60-150℃ for 1-12 hours to obtain graphene-coated copper wire.

[0047] The step 21 is a preparation process of the graphene solution, and the solvent can be acetone, N-methyl pyrrolidone or N,N-dimethylformamide, etc. The specific process of the step 21 can be: inert gas is introduced into different solvents for 1-10 minutes to obtain deoxygenated solvents; the graphene powder is added into the deoxygenated solvents and mixed thoroughly to obtain a graphene dispersion liquid.

[0048] 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 is controlled, so that the oxygen in the system can be reduced, thereby reducing the oxidation of copper and graphene, and the electrical conductivity of the final product can be improved.

[0049] In addition, the graphene powder can be added into the deoxygenated solvents by ultrasonic method, wherein the ultrasonic power is between 100W and 1000W, and the ultrasonic time is between 0.5 and 8 hours.

[0050] Specifically, according to the different solvents in the step 21, different ultrasonic power and ultrasonic time can be determined; wherein when the acetone solvent is used, the corresponding ultrasonic power can be relatively high and the ultrasonic time can be relatively long; and when the N-methyl pyrrolidone or N,N-dimethylformamide is used, the corresponding ultrasonic power can be relatively small and the ultrasonic time can be relatively short, so that the combination of the solvent, the ultrasonic power and the ultrasonic time can realize the sufficient ultrasonic of the graphene dispersion liquid and improve the electrical conductivity of the final product.

[0051] Further, the concentration of the graphene dispersion liquid can be between 0.2mg / ml and 10mg / ml. By limiting the concentration range of the graphene dispersion liquid, it can be ensured that the graphene dispersion liquid can be well wrapped on the outer surface of the copper wire to form a graphene layer, and the electrical conductivity of the final product can be improved. In addition, according to the different required concentrations of the graphene dispersion liquid, the ultrasonic power and the ultrasonic time can be further adjusted in the corresponding range during the ultrasonic process of adding the graphene powder into the deoxygenated solvents, so that the uniformity of the graphene dispersion liquid can be further improved, and the electrical conductivity of the final product can be further improved.

[0052] The step 22 is to dip the graphene dispersion liquid with the absorbent cotton, wrap the absorbent cotton group around one end of the copper wire, and pull the copper wire so that the graphene dispersion liquid on the absorbent cotton group is coated on the surface of the copper wire.

[0053] Specifically, the absorbent cotton group can be slightly dipped in the graphene dispersion liquid, and a slight pressure can be applied to the absorbent cotton group during the pulling process of the copper wire, so that the absorbent cotton group can tightly wrap the copper wire but the soaked graphene dispersion liquid does not drip, so that the graphene dispersion liquid on the absorbent cotton group can be uniformly coated on the surface of the copper wire to form a uniform graphene layer.

[0054] Step 23, place the copper wire coated with graphene dispersion liquid in a vacuum drying oven, dry at 60~150℃ for 1~12 hours, to obtain graphene coated copper wire.

[0055] Specifically, different drying temperatures and drying times can be determined according to different solvents in step 21, wherein acetone can correspond to lower drying temperature and shorter drying time, N-methyl pyrrolidone and N,N-dimethylformamide can correspond to higher drying temperature and longer drying time, and by combining the solvent, drying temperature and drying time, the electrical conductivity can be significantly improved.

[0056] Further, step 3, using electroplating method to plate copper on the outer surface of the copper wire, specifically comprising:

[0057] Step 31, dissolve copper salt in deionized water, adjust the pH to 1~6, to obtain copper electrolyte;

[0058] Step 32, place the copper wire coated with graphene in the electrolytic cell and connect it to the cathode, the anode is pure copper, and at the same time add copper electrolyte to the electrolytic cell until the copper wire is immersed, carry out the electroplating process, so that the copper is coated outside the graphene.

[0059] Among them, step 31 is the preparation process of copper electrolyte. Specifically, the copper salt can be copper sulfate, copper chloride or copper acetate, etc. High-purity copper salt can be dissolved in deionized water, a small amount of concentrated hydrochloric acid is added, and the mixture is stirred to obtain the copper electrolyte. The electrolyte concentration can be controlled between 1mg / ml and saturated solution, and the pH value is controlled between 1~6. In this way, it is beneficial to fully carry out the electroplating process, so that the copper can be well coated on the outer surface of the graphene layer.

[0060] In addition, step 32 is the specific electroplating process. Specifically, the copper wire coated with graphene can be placed in the electrolytic cell, wherein the cathode of the constant current power supply can be connected to the copper wire, and a pure copper rod is used as the anode, and the copper electrolyte is added to the electrolytic cell, so as to form an electroplating system. After starting the constant current power supply, the electroplating process can be started, and finally a copper layer can be electroplated on the outer surface of the graphene layer.

[0061] Further, the electroplating current can be controlled between 1A~10A, and the electroplating time can be controlled between 1~60 minutes. By controlling different current size and electroplating time, the thickness of the electroplated layer can be controlled between 5~100 microns, that is, a copper layer of 5~100 microns can be obtained, which can be 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 microns, etc. The different glossiness of the copper surface can be realized, so that the copper layer can be well wrapped on the outer surface of the graphene layer, and the electrical conductivity of the final product can be improved through the cooperation of the copper layer and the graphene layer.

[0062] Further, the embodiment of the present application realizes the combination of copper and graphene by coating graphene on the copper wire and then plating copper on the graphene, which is simple in operation and low in cost. Moreover, the embodiment of the present application is improved on the basis of the conventional copper wire, so that the conductivity can be significantly improved compared with the conventional copper wire. Compared with the conventional composite copper wire, the embodiment of the present application can further simplify the operation steps and reduce the cost, and the conductivity of the final product can be improved through the synergy of the graphene layer and the copper layer.

[0063] Further, after the copper plating in step 3, the copper wire can be taken out of the electrolytic tank and repeatedly cleaned in deionized water several times until the electrolyte is completely washed away. The method for determining whether the cleaning is complete is to measure the conductivity of the cleaning liquid. When the conductivity of the cleaning liquid is 2 microsiemens per centimeter 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.

[0064] It should be noted that after each step 3, a cleaning process is performed, which can effectively prevent the influence of the electrolyte on the conductivity.

[0065] For step 4, steps 2 and 3 are repeated n times to obtain a graphene composite copper wire.

[0066] Specifically, n can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. Step 2 is the process of coating the graphene dispersion to form a graphene layer, and step 3 is the process of plating a copper layer. After each step 2 and step 3, a composite layer can be obtained on the outer surface of the copper wire. By repeating steps 2 and 3 multiple times, multiple composite layers can be obtained, which can further improve the conductivity. Moreover, the thickness of the graphene layer and the copper layer can be matched to significantly improve the conductivity of the final product.

[0067] Further, after step 4, the following steps are further included:

[0068] Step 5, calcining the graphene composite copper wire in a vacuum furnace: the graphene composite copper wire is placed in a vacuum tube furnace, inert gas is repeatedly introduced multiple times, the temperature is controlled at 950-1000℃, and the temperature is maintained for 0.5-2 hours.

[0069] Step 6, using a drawing device to draw and regularize the diameter of the calcined graphene composite copper wire.

[0070] Step 7, annealing treatment: the graphene composite copper wire of step 6 is placed in a vacuum tube furnace and vacuumed to below 1 Pa, inert gas is repeatedly introduced multiple times, the temperature is controlled at 400-600℃, and the temperature is maintained for 10-30 minutes.

[0071] Specifically, after the graphene composite copper wire is obtained, the graphene composite copper wire can be calcined in a vacuum furnace, then be drawn to a regular wire diameter, and finally be annealed to obtain the final product.

[0072] For step 5, the graphene composite copper wire obtained in step 4 can be placed in a vacuum furnace, vacuumized to below 1 Pa, and then high-purity inert gas such as argon can be introduced to dilute the oxygen concentration for three times. Finally, high-purity argon is introduced into the vacuum furnace to be slightly less than one standard atmospheric pressure, while the temperature is controlled at 950-1000 ℃. At this temperature, the expanded air keeps the vacuum furnace at a positive pressure at all times. The temperature is kept for 0.5-2 hours, and then the power is turned off and the temperature is naturally reduced to room temperature. The calcination can promote the contact between graphene and copper and maintain the electrical conductivity.

[0073] In addition, step 6 is mainly used for measuring 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, a drawing device with a wire diameter smaller than the minimum value is selected for drawing. In this way, the graphene composite copper wire can be drawn with resistance, 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, even if there is a slight difference in the wire diameter of the final graphene composite copper wire due to a slight difference in the electroplating time, the same specification of the drawing device can be selected for drawing, so that multiple graphene composite copper wires with uniform wire diameter can be obtained.

[0074] For step 7, the graphene composite copper wire obtained in step 6 is placed in a vacuum tube furnace and vacuumized to below 1 Pa. High-purity argon is introduced to 1 standard atmospheric pressure, and the oxygen concentration is diluted for three times. Finally, high-purity argon is introduced to be slightly less than one standard atmospheric pressure, and the temperature is controlled at 400-600 ℃. At this temperature, the expanded air keeps the vacuum furnace at a positive pressure at all times. The temperature is kept for 10-30 minutes for annealing treatment, and then the power is turned off and the temperature is naturally reduced to room temperature to take out the graphene composite copper wire, thereby obtaining the final product.

[0075] Further, in some embodiments, the wire diameter of the copper substrate is between 350 and 850 microns.

[0076] Specifically, the wire diameter of the copper substrate can be 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850 microns, and the like. The wire diameter of the copper substrate is between 350 and 850 microns, so that the composite layer can be well matched with the copper substrate, fully play the role of the composite layer, and ensure the electrical conductivity.

[0077] Further, a graphene composite copper wire is prepared by the preparation method. 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 inside to outside.

[0078] In the embodiment of the present application, the copper substrate is treated by electroplating method, and a multi-layer composite layer composed of copper and graphene is formed on the surface of the copper substrate, and finally a graphene composite copper wire is obtained. In this way, the electrical conductivity of copper can be improved, and the process is simple, without too many complicated steps, and the preparation conditions are simple and the cost is low.

[0079] The following is further illustrated by examples, and it should be understood that the specific examples described herein are only used to explain the present application, but not to limit the present application.

[0080] First implementation of Example 1

[0081] Step one, immerse the conventional copper wire (wire diameter 400 microns) in deionized water for ultrasonic treatment for 10 minutes, then transfer it to acetone and ultrasonic treatment again for 10 minutes, take it out and blow dry with high-purity nitrogen, remove the surface stains to obtain clean copper wire.

[0082] Step two, add conventional graphene powder to deoxygenated acetone and ultrasonically treat to obtain a graphene dispersion solution with a concentration of 3 mg / ml, the ultrasonic power is 1000 W and the ultrasonic time is 5 hours. Dip the graphene dispersion solution with absorbent cotton, wrap the clean copper wire with one end of the absorbent cotton, pull the copper wire and slightly apply pressure to the absorbent cotton to evenly apply the graphene dispersion solution on the surface of the copper wire. Place the above-mentioned copper wire in a vacuum drying oven and dry at 60°C for 1 hour to remove the solvent, obtaining a graphene-coated copper wire.

[0083] Step three, place the above-mentioned graphene-coated copper wire in an electroplating tank and connect it to the cathode of a constant current power supply, and the anode is a high-purity copper rod. Add an electrolyte to the electrolytic tank until it covers the copper wire, the electrolyte is prepared from copper sulfate, the pH value is about 2, and the concentration is 120 mg / ml. Turn on the constant current power supply, the current is 1 A, and the electroplating time is 7 minutes, obtaining a graphene composite copper wire with one layer of graphene layer and one layer of copper layer. Take the above-mentioned copper wire out of the electrolytic tank and repeatedly wash it in deionized water several times until the electrolyte is completely washed off. Measure the conductivity of the washing liquid to confirm whether it is clean, and the requirement is 2 microsiemens per centimeter or below, which is close to the conductivity of deionized water.

[0084] Step four, repeat steps two and three a total of three times to obtain a graphene composite copper wire with three layers of composite layer.

[0085] Step five, place the graphene composite copper wire with three layers of composite layer in a vacuum tube furnace, evacuate to below 1 Pa, introduce high-purity argon to 1 atmosphere, dilute the oxygen concentration repeatedly for 3 times, finally introduce high-purity argon to slightly below 1 atmosphere, control the temperature at 950°C. The expanded air keeps the vacuum furnace at a positive pressure at this temperature, and the temperature is kept for 1 hour, then the power is turned off and the temperature is naturally reduced to room temperature to take out the graphene composite copper wire.

[0086] Step six, the diameter of the graphene composite copper wire is about 428 microns, and a 425 micron diameter drawing device is selected for drawing to regularize the graphene composite copper wire and obtain a graphene composite copper wire with uniform diameter size.

[0087] Step seven, the graphene composite copper wire is placed in a vacuum tube furnace, vacuumed to below 1 Pa, high-purity argon is introduced to 1 atmosphere, the oxygen concentration is diluted repeatedly 3 times, finally high-purity argon is introduced to slightly lower than 1 atmosphere, the temperature is controlled at 600℃, the expanded air keeps the vacuum furnace at positive pressure at this temperature, and the annealing treatment is carried out for 20 minutes, then the power is turned off and the temperature is naturally reduced to room temperature to take out the graphene composite copper wire, and the final product is obtained.

[0088] The second implementation of example 1; compared with the first implementation of example 1, only steps one to three and steps five to seven are included, and the final product is a graphene composite copper wire with one composite layer; wherein in step three, the electroplating time is modified to 20 minutes, so that the electroplating time in the second implementation and the sum of the electroplating times of the three times of electroplating in the first implementation are approximately the same, so that the diameter of the graphene composite copper wire obtained in the second implementation and the diameter of the graphene composite copper wire obtained in the first implementation are approximately the same, so that the diameter of the graphene composite copper wire measured in the second implementation is about 428 microns, and a 425 micron diameter drawing device can be selected for drawing.

[0089] The third implementation of example 1: compared with the first implementation of example 1, step four is modified to repeat steps two and three a total of 2 times to obtain a graphene composite copper wire with two composite layers, and the remaining steps remain unchanged; wherein the electroplating time in step three is modified to 10 minutes, i.e. the single electroplating time is 10 minutes, so that the sum of the two electroplating times in the third implementation and the sum of the electroplating times of the three times of electroplating in the first implementation are approximately the same, so that the diameter of the graphene composite copper wire obtained in the third implementation and the diameter of the graphene composite copper wire obtained in the first implementation are approximately the same, so that the diameter of the graphene composite copper wire measured in the third implementation is about 426 microns, and a 425 micron diameter drawing device can be selected for drawing.

[0090] The fourth implementation of embodiment 1: compared with the first implementation of embodiment 1, step four is modified to repeat steps two and three a total of 5 times to obtain a graphene composite copper wire with five composite layers, and the remaining steps remain unchanged; wherein the plating time of the electroplating in step three 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 is approximately the same as the sum 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 approximately the same as the wire diameter of the graphene composite copper wire obtained in the first implementation, so that the wire diameter of the graphene composite copper wire measured in the third implementation is about 431 microns, and a 425-micron-aperture drawing device can be selected for drawing.

[0091] Comparative example 1: compared with embodiment 1, only including step one of the copper wire.

[0092] First implementation of embodiment 2

[0093] Step one, immerse the conventional copper wire (wire diameter 600 microns) in deionized water for ultrasonic treatment for 10 minutes, then transfer it into acetone for ultrasonic treatment again for 10 minutes, take it out and blow it dry with high-purity nitrogen gas, remove the surface stains to obtain a clean copper wire.

[0094] Step two, add conventional graphene powder to deoxygenated N,N-dimethylformamide, and ultrasonically treat to obtain a graphene dispersion liquid with a concentration of 4.5 mg / ml, ultrasonic power 800 W, ultrasonic time 2 hours. Dip the graphene dispersion liquid with absorbent cotton, wrap the absorbent cotton around one end of the clean copper wire, pull the copper wire and slightly apply pressure to the absorbent cotton to evenly apply the graphene dispersion liquid on the surface of the copper wire. Place the above-mentioned copper wire in a vacuum drying oven and dry at 150°C for 12 hours to remove the solvent to obtain a graphene-coated copper wire.

[0095] Step three, place the above-mentioned graphene-coated copper wire in an electroplating tank and connect it to the cathode of a constant current power supply, and the anode is a high-purity copper rod. Add an electrolyte to the electrolytic tank until it covers the copper wire, the electrolyte is prepared from copper chloride, the pH value is about 2, and the concentration is 130 mg / ml. Turn on the constant current power supply, the current is 2 A, and the electroplating time is 6 minutes to obtain a graphene composite copper wire with one graphene layer and one copper layer. Take the above-mentioned graphene composite copper wire out of the electrolytic tank and repeatedly wash it several times in deionized water until the electrolyte is completely washed off. Confirm whether it is clean by measuring the conductivity of the washing liquid, which requires to be below 2 microsiemens per centimeter, i.e. close to the conductivity of deionized water.

[0096] Step four, repeat steps two and three a total of 5 times to obtain a graphene composite copper wire with five composite layers.

[0097] Step five, the graphene composite copper wire is placed in a vacuum tube furnace, vacuumed to below 1 Pa, high-purity argon is introduced to 1 standard atmosphere, the oxygen concentration is diluted for 3 times, finally high-purity argon is introduced to slightly below 1 standard atmosphere, the temperature is controlled at 1000 ℃. The expanded air at this temperature keeps the vacuum furnace in positive pressure all the time, heat preservation is carried out for 1 hour, then the power is turned off and the graphene composite copper wire is taken out after the temperature naturally decreases to room temperature.

[0098] Step six, the diameter of the graphene composite copper wire is about 655 microns, a 650 micron aperture drawing device is selected to draw the graphene composite copper wire, and the graphene composite copper wire with uniform size is obtained.

[0099] Step seven, the graphene composite copper wire is placed in a vacuum tube furnace, vacuumed to below 1 Pa, high-purity argon is introduced to 1 standard atmosphere, the oxygen concentration is diluted for 3 times, finally high-purity argon is introduced to slightly below 1 standard atmosphere, the temperature is controlled at 600 ℃, the expanded air at this temperature keeps the vacuum furnace in positive pressure all the time, annealing treatment is carried out for 20 minutes, then the power is turned off and the graphene composite copper wire is taken out after the temperature naturally decreases to room temperature, and the final product is obtained.

[0100] The second implementation of example 2; compared with the first implementation of example 2, only steps one to three and steps five to seven are included, and the final product is a graphene composite copper wire with one composite layer; wherein in step three, the electroplating time is modified to 31 minutes, so that the sum of the electroplating time in the second implementation and the electroplating time of 5 times in the first implementation is approximately the same, so that the diameter of the graphene composite copper wire obtained in the second implementation is approximately the same as the diameter of the graphene composite copper wire obtained in the first implementation, so that the diameter of the graphene composite copper wire measured in the second implementation is about 653 microns, and a 650 micron aperture drawing device can be selected for drawing.

[0101] The third implementation of example 2: compared with the first implementation of example 2, step four is modified to repeat steps two and three a total of 2 times to obtain a graphene composite copper wire with two composite layers, and the remaining steps remain unchanged; wherein in step three, the electroplating time is modified to 16 minutes, i.e. the single electroplating time is 16 minutes, so that the sum of the electroplating time of 2 times in the third implementation is approximately the same as the sum of the electroplating time of 5 times in the first implementation, so that the diameter of the graphene composite copper wire obtained in the third implementation is approximately the same as the diameter of the graphene composite copper wire obtained in the first implementation, so that the diameter of the graphene composite copper wire measured in the third implementation is about 657 microns, and a 650 micron aperture drawing device can be selected for drawing.

[0102] The fourth implementation of Example 2: Compared with the first implementation of Example 2, step four is modified to repeat steps two and three a total of 3 times to obtain a graphene composite copper wire with three layers of composite layers, and the remaining steps remain unchanged; wherein in step three, 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 times of electroplating in the fourth implementation is approximately the same as the sum of the electroplating times of the 5 times of electroplating in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the fourth implementation is approximately the same as the wire diameter of the graphene composite copper wire obtained in the first implementation, so that the wire diameter of the graphene composite copper wire measured in the fourth implementation is about 660 microns, and a 650-micron-aperture drawing device can be selected for drawing.

[0103] Comparative Example 2: Compared with Example 2, only the copper wire in step one is included.

[0104] First implementation of Example 3

[0105] Step one, immerse the conventional copper wire (wire diameter 800 microns) in deionized water for ultrasonic treatment for 10 minutes, then transfer it into acetone for ultrasonic treatment again for 10 minutes, take it out and blow it dry with high-purity nitrogen gas, remove the surface stains to obtain a clean copper wire.

[0106] Step two, add conventional graphene powder to deoxygenated N,N-dimethylformamide, and ultrasonically treat to obtain a graphene dispersion liquid with a concentration of 6 mg / ml, the ultrasonic power is 800 W, and the ultrasonic time is 2 hours. Dip the graphene dispersion liquid with absorbent cotton, wrap the absorbent cotton around one end of the clean copper wire, pull the copper wire and slightly apply pressure to the absorbent cotton to evenly apply the graphene dispersion liquid on the surface of the copper wire. Place the above-mentioned copper wire in a vacuum drying oven and dry at 150°C for 12 hours to remove the solvent, to obtain a graphene-coated copper wire.

[0107] Step three, place the above-mentioned graphene-coated copper wire in an electroplating tank and connect it to the cathode of a constant-current power supply, and the anode is a high-purity copper rod. Add an electrolyte to the electrolytic tank until it covers the copper wire, the electrolyte is prepared from copper chloride, the pH value is about 1, and the concentration is 140 mg / ml. Turn on the constant-current power supply, the current is 3 A, and the electroplating time is 5 minutes, to obtain a graphene composite copper wire with one layer of graphene layer and one layer of copper layer. Take the above-mentioned graphene composite copper wire out of the electrolytic tank and repeatedly wash it several times in deionized water until the electrolyte is completely washed off. Confirm whether it is clean by measuring the conductivity of the washing liquid, which requires to be below 2 microsiemens per centimeter, i.e. close to the conductivity of deionized water.

[0108] Step four, repeat steps two and three a total of 5 times to obtain a graphene composite copper wire with five layers of composite layers.

[0109] Step five, the graphene composite copper wire is placed in a vacuum tube furnace, vacuumed to below 1 Pa, high-purity argon is introduced to 1 standard atmosphere, the oxygen concentration is diluted for 3 times, finally high-purity argon is introduced to slightly below 1 standard atmosphere, the temperature is controlled at 1000℃. The expanded air at this temperature keeps the vacuum furnace in positive pressure all the time, heat preservation for 1 hour, then the power is turned off and the temperature is naturally reduced to room temperature to take out the graphene composite copper wire.

[0110] Step six, the diameter of the graphene composite copper wire is about 855 microns, an 850 micron aperture drawing device is selected to draw, the graphene composite copper wire is regularized, and the graphene composite copper wire with uniform size is obtained.

[0111] Step seven, the graphene composite copper wire is placed in a vacuum tube furnace, vacuumed to below 1 Pa, high-purity argon is introduced to 1 standard atmosphere, the oxygen concentration is diluted for 3 times, finally high-purity argon is introduced to slightly below 1 standard atmosphere, the temperature is controlled at 600℃, the expanded air at this temperature keeps the vacuum furnace in positive pressure all the time, heat preservation for 20 minutes for annealing treatment, then the power is turned off and the temperature is naturally reduced to room temperature to take out the graphene composite copper wire, and the final product is obtained.

[0112] The second implementation of example 3; compared with the first implementation of example 3, only steps one to three and steps five to seven are included, and the final product is a graphene composite copper wire with one composite layer; wherein in step three, the electroplating time is modified to 26 minutes, so that the sum of the electroplating time in the second implementation and the electroplating time of 5 times in the first implementation is approximately the same, so that the diameter of the graphene composite copper wire obtained in the second implementation is approximately the same as the diameter of the graphene composite copper wire obtained in the first implementation, so that the diameter of the graphene composite copper wire measured in the second implementation is about 857 microns, and an 850 micron aperture drawing device can be selected for drawing.

[0113] The third implementation of example 3: compared with the first implementation of example 3, step four is modified to repeat steps two and three a total of 2 times to obtain a graphene composite copper wire with two composite layers, and the remaining steps remain unchanged; wherein in step three, the electroplating time is modified to 13 minutes, i.e. the single electroplating time is 13 minutes, so that the sum of the electroplating time of 2 times in the third implementation is approximately the same as the sum of the electroplating time of 5 times in the first implementation, so that the diameter of the graphene composite copper wire obtained in the third implementation is approximately the same as the diameter of the graphene composite copper wire obtained in the first implementation, so that the diameter of the graphene composite copper wire measured in the third implementation is about 854 microns, and an 850 micron aperture drawing device can be selected for drawing.

[0114] The fourth implementation of the embodiment 3: compared with the first implementation of the embodiment 3, the step four is modified to repeat the step two and the step three for a total of 3 times to obtain the graphene composite copper wire with three layers of composite layers, and the remaining steps remain unchanged; wherein in the step three, the electroplating time is modified to 8 minutes, that is, the single electroplating time is 8 minutes, thus the sum of the electroplating times of the 3 times of electroplating in the fourth implementation is approximately the same as the sum of the electroplating times of the 5 times of electroplating in the first implementation, so that the wire diameter of the graphene composite copper wire obtained in the fourth implementation is approximately the same as 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 about 856 microns, and a 850 micron pore size drawing device can be selected for drawing.

[0115] The comparative example 3: compared with the embodiment 3, only the copper wire in the step one is included.

[0116] The electrical conductivity of each implementation of each comparative example and each embodiment is measured to obtain the following table results.

[0117]

[0118] It can be known from the test data in the table that the electrical conductivity of the graphene composite layer of the embodiment of the present application is much higher than that of the traditional copper wire. Meanwhile, for different implementations of the same embodiment, there is only a slight difference in the electroplating time, and the graphene composite copper wires in each implementation are uniformly drawn by using the same specification drawing device, so that the wire diameters of the graphene composite copper wires in each implementation are consistent. From the test results in the table, it can be known that the more the composite layers are, the higher the electrical conductivity is.

[0119] It should be noted that the "consistent wire diameters of the graphene composite copper wires in each implementation" can be understood as the "thicknesses of the conductive layers" in each implementation being the same, that is, under the same embodiment, whether it is one layer of composite layer or five layers of composite layer, the wire diameters of the obtained graphene composite copper wires are the same, and it is not simply that the "conductive layer" outside the copper wire is more to make the electrical conductivity high, but under the condition that the "conductive layer thicknesses" are the same, due to the multiple times of compounding, the electrical conductivity is high, that is, in addition to the influence of the composite layer outside the copper wire on the electrical conductivity, the mutual cooperation between the multiple composite layers can also significantly improve the electrical conductivity.

Claims

1. A method of preparing a graphene composite copper wire, characterized by, include: Step 1: Provide a copper substrate; Step 2: Pass inert gas through different solvents for 1-10 minutes to obtain deoxygenated solvents; Graphene powder is added to an oxygen-deoxidizing solvent and mixed thoroughly to obtain a graphene dispersion. A cotton ball is soaked in the graphene dispersion and wrapped around one end of a copper wire. The copper wire is pulled to coat the surface of the copper wire with the graphene dispersion. The copper wire coated with the graphene dispersion is placed in a vacuum drying oven and dried at 60℃~150℃ for 1~12 hours to obtain a graphene-coated copper wire. The solvent includes any one of acetone, N-methylpyrrolidone, and N,N-dimethylformamide. Step 3: Dissolve copper salt in deionized water and adjust the pH to between 1 and 6 to obtain copper electrolyte; place the copper wire coated with graphene in the electrolytic cell and connect it to the cathode, with pure copper as the anode; add copper electrolyte to the electrolytic cell until it covers the copper wire and carry out the electroplating process to coat copper on the outside of the graphene. Step 4: Repeat steps 2 and 3 n times to obtain graphene composite copper wire; the graphene composite copper wire includes a copper substrate and several composite layers covering 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 sequentially from the inside to the outside. Step 5: Calcination of graphene composite copper wire in a vacuum furnace: Place the graphene composite copper wire in a vacuum tube furnace, repeatedly introduce inert gas, control the temperature at 950℃~1000℃, and hold for 0.5~2 hours. Step 6: Use a drawing tool to draw and straighten the diameter of the calcined graphene composite copper wire. Step 7, Annealing: Place the graphene composite copper wire from step 6 in a vacuum tube furnace and evacuate it to below 1 Pa. Repeatedly introduce inert gas and control the temperature at 400℃~600℃ for 10 minutes~30 minutes.

2. The method for preparing graphene composite copper wire according to claim 1, characterized in that, The electroplating current ranges from 1A to 10A, and the electroplating time is from 1 to 60 minutes.

3. The method for preparing graphene composite copper wire according to claim 2, characterized in that, The thickness of the electroplated layer is between 5 and 100 micrometers.

4. The method for preparing graphene composite copper wire according to claim 1, characterized in that, The wire diameter of the copper substrate is between 350 and 850 micrometers.

5. A graphene composite copper wire, characterized by, The graphene composite copper wire is prepared using the preparation method according to any one of claims 1 to 4. It includes a copper substrate and a plurality of composite layers covering 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 sequentially from the inside to the outside.

Images