Preparation method of graphene copper conductor and graphene copper conductor

Abstract

The invention particularly relates to a preparation method of a graphene copper conductor and the graphene copper conductor. The preparation method of the graphene copper conductor comprises the steps that S1, the surface of a copper substrate is coated with a graphene oxide layer; s2, coating the surface of the graphene oxide layer with a premixed layer of nickel and graphene oxide; s3, heating treatment is carried out, so that graphene oxide in the graphene oxide layer and the pre-mixing layer is reduced to form graphene, and the graphene is molten into nickel metal; s4, cooling is carried out at a set cooling rate, so that the graphene molten into the nickel metal is separated out, and a graphene layer and a nickel and graphene mixed layer are formed; and S5, coating the surface of the mixed layer with a nickel layer. The graphene copper conductor prepared by the invention has relatively good conductivity and relatively long service life.

Description

Technical Field

[0001] The present application relates to the technical field of electrical contact materials, and more particularly, to a preparation method of a graphene copper conductor and a graphene copper conductor. Background Art

[0002] Copper, as a conductor, has excellent electrical conductivity and is currently a widely used conductor. It can be used as a wire, a connecting wire or an electrical contact conductor. In actual use, it needs to face the invasion of dust, rain, snow, water vapor, dirt, etc., the erosion of corrosive gases such as sulfur dioxide, hydrogen sulfide, nitrogen dioxide, etc. or the corrosion of oxygen. These external real conditions will cause the oxidation of the copper surface, an increase in resistance or the corrosion of the electrical contact conductor, resulting in poor electrical conductivity.

[0003] To improve the above problems, generally, an anti-corrosion film layer is added to the surface of the copper conductor, or nickel is electroplated on the surface of the copper conductor to form an anti-corrosion layer, but the existing improvement methods have introduced new problems. After adding an anti-corrosion film layer to the surface of the copper conductor, the electrical conductivity of the copper conductor will be reduced. Therefore, the structural distribution of the anti-corrosion film layer is further improved, and substances with strong conductivity (such as graphene, graphene oxide, carbon nanotubes) are added to the anti-corrosion film layer. The substances with strong conductivity are directly connected to the internal copper conductor to play a conductive role, and the substances with strong conductivity can also relieve corrosion. Although this design can solve the problems of anti-corrosion and electrical conductivity on the surface of the copper conductor under certain conditions, in the face of a complex application environment, the anti-corrosion film layer is still prone to burning or falling off, and the service life is short. For the anti-corrosion layer formed by electroplating nickel on the surface of the copper conductor, nickel metal will generate a copper-nickel eutectic with the copper matrix at high temperature, affecting the electrical conductivity of the copper matrix. Therefore, how to improve the service life and electrical conductivity of the copper conductor is still one of the key research and development directions in this field. Summary of the Invention

[0004] The present application aims to provide a preparation method of a graphene copper conductor and a graphene copper conductor to solve the problem that it is difficult to balance the service life and electrical conductivity of copper conductors in the prior art.

[0005] The embodiments of the present application are implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a preparation method of a graphene copper conductor, which includes:

[0007] S1: Coating a graphene oxide layer on the surface of a copper matrix;

[0008] S2: Coating a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer;

[0009] S3: Performing a heat treatment to reduce the graphene oxide in the graphene oxide layer and the pre-mixed layer to form graphene, and melting the graphene into the nickel metal;

[0010] S4: Cool down at a set cooling rate to precipitate the graphene incorporated into the nickel metal, forming a mixed layer of graphene, nickel, and graphene;

[0011] S5: Coat a nickel layer on the surface of the mixed layer.

[0012] In one embodiment of the present application, in step S3, before the heat treatment, vacuum drying is first carried out.

[0013] In one embodiment of the present application, in step S3, the heat treatment is carried out under vacuum conditions and a pressure of 20 - 30 MPa.

[0014] In one embodiment of the present application, in step S3, the temperature is first raised to 850 - 1050 °C and then pressurized.

[0015] In one embodiment of the present application, in step S3, the temperature is first raised to 500 °C at a first heating rate, and then raised to the set temperature at a second heating rate and held for 40 - 50 min, where the first heating rate is less than the second heating rate.

[0016] In one embodiment of the present application, the first heating rate is 10 °C / min and the second heating rate is 20 °C / min.

[0017] In one embodiment of the present application, in step S3, pressurization is carried out by injecting a mixed gas, and the mixed gas is a mixture of hydrogen and an inert gas.

[0018] In one embodiment of the present application, in step S4, the set cooling rate is 8 - 20 °C / min.

[0019] In one embodiment of the present application, in step S1, a graphene oxide solution is prepared, and the copper substrate is immersed in the graphene oxide solution for electroplating deposition of graphene oxide;

[0020] The graphene oxide solution is configured to contain copper oxide and / or silver oxide.

[0021] In one embodiment of the present application, the content of copper oxide is 0.3 - 1.5 mg / L, and the content of silver oxide is 0.3 - 1.2 mg / L.

[0022] In one embodiment of the present application, in step S2, a pre-mixed layer of nickel and graphene oxide is prepared on the surface of the graphene oxide layer by electroplating. The plating solution for preparing the pre-mixed layer includes 1.2 - 3.5 g / L of graphene oxide, 12 - 20 g / L of nickel chloride, 340 - 380 g / L of nickel sulfamate, 20 - 45 g / L of boric acid, and 10 - 30 g / L of phosphomolybdic acid. The temperature of the plating solution for preparing the pre-mixed layer is 35 - 50 °C, the pH value is 5 - 5.5, and the current density is controlled at 4.5 - 5 A / dm2.

[0023] In one embodiment of the present application, in step S5, a nickel layer is prepared on the surface of the mixed layer by electroplating. The plating solution for preparing the nickel layer includes 12 - 20 g / L of nickel chloride, 340 - 380 g / L of nickel sulfamate, 20 - 45 g / L of boric acid, and 10 - 30 g / L of phosphomolybdic acid. The temperature of the plating solution for preparing the nickel layer is 35 - 50 °C, the pH value is 3 - 4.5, and the current density is controlled at 4.5 - 5 A / dm2.

[0024] In one embodiment of the present application, in step S1, a graphene oxide layer with a thickness of 0.5 - 20 μm is prepared.

[0025] In one embodiment of the present application, in step S2, a pre-mixed layer of nickel and graphene oxide with a thickness of 3 - 200 μm is prepared.

[0026] In a second aspect, an embodiment of the present application provides a graphene copper conductor, which includes:

[0027] A copper substrate;

[0028] A graphene layer coated on the surface of the copper substrate;

[0029] A mixed layer of nickel and graphene covering the graphene layer;

[0030] A nickel layer covering the mixed layer;

[0031] Alternatively, the graphene copper conductor is prepared by using the preparation method of the graphene copper conductor according to any one of claims 1 - 14.

[0032] In one embodiment of the present application, the total number of graphene layers in the graphene layer and the mixed layer is 3 - 6 layers.

[0033] In one embodiment of the present application, the mixed layer includes a nickel matrix and graphene. The nickel matrix has a number of pores, and the graphene is formed within the pores and on the surface of the nickel matrix.

[0034] Advantages of the technical solution of the present application: In the technical solution provided by the embodiment of the present application, first, a graphene oxide layer with a certain thickness is coated on the surface of a copper substrate, and then a pre-mixed layer of nickel and graphene oxide is coated on the surface of the graphene oxide layer. In the pre-mixed layer, nickel metal forms a nickel matrix (the nickel metal described in the following embodiments can be regarded as a nickel matrix), and graphene oxide is formed inside and on the surface of the nickel matrix. Graphene oxide can largely prevent the large-area contact between nickel and the copper substrate, prevent the mutual melting of copper and nickel, and ensure good electrical conductivity. Then, heating is carried out. Graphene oxide will be reduced at a certain temperature, removing oxygen-containing groups to generate graphene, carbon dioxide and water. Since carbon dioxide and water form pores inside the nickel matrix when discharged from the nickel matrix, and there may also be certain voids in the nickel matrix itself, and nickel metal itself will melt carbon under heating conditions, so that the formed graphene melts into the nickel matrix and forms void points in situ. After the redox reaction and mutual melting are completed, cooling is carried out at a set cooling rate. The carbon melted in nickel re-precipitates and grows into a new graphene layer. The newly precipitated graphene layer can more uniformly fill the voids and pores inside the nickel matrix and more uniformly cover the surface of the nickel matrix. It not only blocks the contact between nickel and the copper substrate, prevents the formation of a mutual melt of copper and nickel at high temperature, but also plays a role in enhancing conductivity. Finally, a nickel layer is coated on the surface of the mixed layer of nickel and graphene. The nickel layer can further fill the surface voids of the mixed layer, improve the overall density, and also coat all the graphene in the mixed layer, so that the graphene copper conductor as a whole can better adapt to different complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic structural diagram of the surface of a copper substrate after preparing a graphene oxide layer and a pre-mixed layer provided by an embodiment of the present application;

[0037] Figure 2 It is a schematic structural diagram of a graphene copper conductor provided by an embodiment of the present application.

[0038] Reference numerals: 1 - copper substrate, 2 - graphene layer, 3 - mixed layer, 3.1 - nickel matrix, 3.2 - graphene, 4 - nickel layer, 21 - graphene oxide layer, 31 - pre-mixed layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0040] In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" usually refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. In addition, in the description of the present application, the term "including" means "including but not limited to". The terms first, second, third, etc. are only used as labels, and do not impose numerical requirements or establish an order.

[0041] In the present application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural.

[0042] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one of the following items (pieces)" or similar expressions refer to any combination of these items, including any combination of single item (piece) or plural items (pieces). For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a - b (that is, a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0043] The various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub - ranges and the single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub - ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the single numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0044] It should be noted that like reference numerals and letters refer to like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0045] An embodiment of the present application provides a method for preparing a graphene copper conductor and the graphene copper conductor, so as to improve the service life of the copper conductor and enable the copper conductor to have good electrical conductivity.

[0046] The method for preparing the graphene copper conductor includes:

[0047] S1: As Figure 1 shown, a graphene oxide layer 21 is coated on the surface of the copper substrate 1;

[0048] S2: A pre-mixed layer 31 of nickel and graphene oxide is coated on the surface of the graphene oxide layer 21;

[0049] S3: Heat treatment is carried out to reduce the graphene oxide in the graphene oxide layer and the pre-mixed layer to form graphene, and the graphene is melted into the nickel metal;

[0050] S4: Cooling is carried out at a set cooling rate to precipitate the graphene melted into the nickel metal, forming a graphene layer 2 and a mixed layer 3 of nickel and graphene;

[0051] S5: A nickel layer 4 is coated on the surface of the mixed layer.

[0052] The technical solution provided by the embodiment of the present application, as Figure 1 shown, by first coating a graphene oxide layer 21 with a certain thickness on the surface of the copper substrate 1, and then coating a pre-mixed layer 31 of nickel and graphene oxide on the surface of the graphene oxide layer 21, the nickel metal in the pre-mixed layer 31 forms a nickel matrix 3.1 (the nickel metal described in the following embodiments can all be regarded as the nickel matrix), and the graphene oxide is formed inside and on the surface of the nickel matrix. The graphene oxide layer 21 can largely prevent the nickel metal from coming into large-area contact with the copper substrate 1, prevent copper-nickel mutual melting, and ensure good electrical conductivity; then heating is carried out, as Figure 2As shown, the graphene oxide in the graphene oxide layer 21 and the premixed layer 31 will be reduced at a certain temperature, removing oxygen-containing groups to generate graphene, carbon dioxide and water. Since the carbon dioxide and water form pores inside the nickel matrix 3.1 when discharging from the nickel matrix 3.1, and there may also be certain voids in the nickel matrix 3.1 itself, and the nickel metal itself will melt carbon under heating conditions, making the formed graphene dissolve in the nickel matrix 3.1 and form void points in situ; after the redox reaction and mutual melting are completed, it is cooled at a set cooling rate. The carbon dissolved in the nickel re-precipitates and grows into new graphene 3.2. The re-precipitated graphene 3.2 can more uniformly fill the voids and pores inside the nickel matrix 3.1 and more uniformly cover the surface of the nickel matrix 3.1. It not only blocks the contact between the nickel and the copper matrix 1, preventing the formation of a mutual melt between copper and nickel at high temperatures, but also plays a role in enhancing conductivity. Finally, a nickel layer 4 is coated on the surface of the mixed layer 3 of nickel and graphene. The nickel layer 4 can further fill the surface voids of the mixed layer, improve the overall density, and also coat all the graphene in the mixed layer 3, so that the graphene copper conductor as a whole can better adapt to different complex environments, such as Figure 2 shown.

[0053] It should be noted that a part of the graphene layer 2 may also dissolve in the nickel metal and re-precipitate.

[0054] Specifically, in step S1, a graphene oxide solution is first prepared, and the graphene oxide layer is prepared on the surface of the copper matrix by electrodeposition.

[0055] The concentration of the graphene oxide solution is 3.1 - 4.2 mg / L, and the acidity and alkalinity are neutral. The electrical contact conductor with a metal coating is connected to the anode, and the copper matrix, anode, and cathode are immersed in the solution. The anode and cathode are energized, so that the graphene oxide is electrodeposited on the surface of the copper matrix, and it is ensured that the surface of the copper matrix is completely coated with graphene oxide.

[0056] Optionally, the electrode voltage is controlled at 28 v, and the temperature of the graphene oxide solution is 30 - 35 °C.

[0057] Optionally, the thickness of the prepared graphene oxide layer is 0.5 - 20 μm, so as to ensure that the copper matrix can be well covered and isolated, and there is enough graphene to cover the surface of the nickel matrix when a new graphene layer re-precipitates in step S4.

[0058] Among them, the graphene oxide can be directly purchased or prepared by conventional methods in the art, such as by the process of graphite in boric acid, concentrated sulfuric acid and potassium permanganate. Those skilled in the art should be able to understand the specific preparation means, which will not be elaborated in the embodiments of the present application.

[0059] In some embodiments, the graphene oxide solution is configured to contain copper oxide and / or silver oxide.

[0060] When the graphene oxide solution contains copper oxide, the copper oxide will be reduced to form metallic copper after the reduction of graphene oxide. The metallic copper formed by this reduction forms a copper-nickel alloy with nickel at high temperatures. On the one hand, new void points will be formed at the positions where the copper oxide is located, increasing the space for graphene precipitation in step S4. On the other hand, the copper-nickel alloy will reduce the carbon melting ability of nickel, increasing the precipitation amount of graphene in step S4. Moreover, since the nickel layer forms a copper-nickel alloy with the newly reduced copper, it can also reduce the mutual melting of the nickel layer and the copper substrate, playing a protective role for the internal copper substrate and also playing a certain fixing role for the external nickel layer to prevent the coating from falling off. Optionally, the content of copper oxide is 0.3-1.5 mg / L.

[0061] When the oxide contained in the graphene oxide solution is silver, the silver oxide will be reduced to form metallic silver after the reduction of graphene oxide. The mutual melting of silver and the copper substrate forms a silver-copper eutectic on the surface of the copper substrate, which can effectively reduce the fusion of copper and nickel. At the same time, void points are also formed at the positions where the silver oxide is located, increasing the space for graphene precipitation and effectively increasing the conductivity. Optionally, the content of silver oxide is 0.3-1.2 mg / L.

[0062] Compared with directly coating a graphene layer on the surface of the copper substrate, the embodiment of the present application uses electro-deposition to deposit a graphene oxide layer on the surface of the copper substrate, which is technically more convenient for processing and can solve the problem of graphene agglomeration.

[0063] In step S2, a pre-mixed layer of nickel and graphene oxide is prepared on the surface of the graphene oxide layer by electroplating.

[0064] That is, a plating solution for the pre-mixed layer of nickel and graphene oxide is first prepared. The concentration of graphene oxide in the plating solution is 1.2-3.5 g / L, the concentration of nickel chloride is 12-20 g / L, the concentration of nickel sulfamate is 340-380 g / L, the concentration of boric acid is 20-45 g / L, and the concentration of phosphomolybdic acid is 10-30 g / L.

[0065] Then, the temperature of the plating solution is controlled to be 35-50 °C, the pH value is 5-5.5, and the current density is controlled to be 4.5-5 A / dm 2 Electroplating deposition is carried out, and graphene oxide and nickel are deposited together on the surface of the copper substrate coated with the graphene oxide layer.

[0066] Optionally, the thickness of the prepared pre-mixed layer of nickel and graphene oxide is 3-200 μm to ensure good coating performance.

[0067] It should be noted that during the electroplating process, some graphene oxide may be reduced to graphene at the cathode and deposited together with nickel. At the same time, the concentration of graphene oxide is controlled to be not less than 1 g / L to prevent a large amount of graphene oxide from being reduced to graphene.

[0068] In step S3, first, the copper substrate with the pre-mixed layer successively coated with a graphene oxide layer, graphene oxide and nickel is dried under vacuum. Under vacuum drying conditions, most of the surface moisture can be removed. On the one hand, it can drain the moisture and open voids, and on the other hand, it can avoid the influence of this part of moisture on subsequent reactions.

[0069] Then, heat treatment is carried out under vacuum conditions and at a pressure of 20 - 30 MPa to decompose the graphene oxide by reduction.

[0070] Furthermore, during the heat treatment, the vacuum conditions are always maintained. First, the temperature is raised to 850 - 1050 °C, and then the pressure is increased to 20 - 30 MPa.

[0071] In some embodiments, the temperature is first raised to 500 °C at a first heating rate, and then the temperature is raised to the set temperature (i.e., 850 - 1050 °C) at a second heating rate and maintained for 40 - 50 min, and the first heating rate is less than the second heating rate.

[0072] The release process of the oxide involves the internal structural changes and channel formation within the oxide molecules. The lower first heating rate can help the oxide molecules in the graphene oxide gradually release oxygen, avoiding incomplete reduction of the oxide molecules before releasing oxygen due to too fast heating.

[0073] When the graphene oxide is heated to above 500 °C, its internal structure and channels tend to be stable. At this time, heating at a faster second heating rate provides sufficient energy for the redox reaction and promotes the acceleration of the redox reaction.

[0074] After the temperature is raised to the set temperature, it is maintained for 40 - 50 min to fully reduce the graphene oxide under high temperature and high pressure.

[0075] Therefore, by first heating at a decreasing first heating rate, then heating at a larger second heating rate, and then maintaining high temperature and high pressure for 40 - 50 min, it is possible to better balance the release of oxide molecules and the reaction rate, thereby obtaining a more ideal reduction effect of graphene oxide.

[0076] Optionally, the first heating rate is 10 °C / min and the second heating rate is 20 °C / min.

[0077] In some embodiments, in step S3, pressurization is performed by injecting a mixed gas, wherein the mixed gas is a mixture of hydrogen and an inert gas, and the inert gas includes one or more of nitrogen, argon or neon.

[0078] By injecting a pressurized gas mixture consisting of hydrogen and inert gas, not only can the moisture, carbon dioxide, etc. produced by the decomposition of graphene oxide in the conductor material be squeezed out from the inside of the metal conductor, but the small amount of hydrogen contained in the mixed gas can also prevent the metal from being oxidized, ensuring the formation of the graphene layer and the mixed layer of nickel and graphene.

[0079] During step S3, some spaces are formed inside the nickel metal. These spaces include pores formed when carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel metal, and voids formed in situ when the graphene generated by oxidation and reduction melts into the nickel metal. In addition, there are gaps that the nickel metal itself has during electrodeposition forming.

[0080] After step S4, the product is cooled at a set cooling rate so that the graphene melted into the nickel metal is re-precipitated to form a graphene layer and a mixed layer of nickel and graphene, wherein the cooling rate is set to 8-20°C / min.

[0081] The reprecipitated graphene can be relatively evenly distributed in the internal space of nickel metal and on the surface of nickel metal, ensuring the isolation of copper and nickel, avoiding mutual melting of copper and nickel, and ensuring good electrical conductivity. By controlling the cooling rate, graphene can grow relatively evenly on the surface and internal space of nickel metal, and contribute to the formation of multilayer graphene. Generally speaking, 3-6 layers of graphene can be formed at a set cooling rate of 8-20℃ / min.

[0082] The mixed layer composed of nickel and 3-6 layers of graphene not only has excellent conductivity, but also has a firm bond with the copper matrix.

[0083] Finally, after step S5, a nickel layer is prepared on the surface of the mixed layer formed by nickel and graphene. The newly generated nickel layer fills the remaining gaps in the nickel metal densely, improves the overall density, and also covers the entire mixed layer to form the final product of the graphene copper conductor. The final product can better adapt to different complex environments because it has the protection of the nickel layer on the surface.

[0084] In some embodiments, the nickel layer is formed on the surface of the mixed layer by electroplating.

[0085] Exemplarily, a plating solution for preparing a nickel layer is first prepared, and the plating solution for preparing a nickel layer includes nickel chloride with a concentration of 12-20 g / L, nickel aminosulfonate with a concentration of 340-380 g / L, boric acid with a concentration of 20-45 g / L, and phosphomolybdic acid with a concentration of 10-30 g / L.

[0086] Then, control the temperature of the plating solution for preparing the nickel layer to be 35 - 50 °C, the pH value to be 3 - 4.5, and control the current density to be 4.5 - 5 A / dm² for electroplating deposition, so that the entire surface of the nickel-metal coated mixed layer is formed with a nickel layer.

[0087] Second, as Figure 2 shown, an embodiment of the present application provides a graphene copper conductor. This graphene copper conductor is formed by using the preparation method of the graphene copper conductor described in the first aspect. Or, this graphene copper conductor includes a copper substrate 1, a graphene layer 2, a mixed layer 3 of nickel and graphene, and a nickel layer 4. Among them, the graphene layer 2 is coated on the surface of the copper substrate 1, the mixed layer 3 of nickel and graphene covers the graphene layer 2, and the nickel layer 4 covers the mixed layer 3.

[0088] Through layer-by-layer coverage, it plays a better anti-corrosion role. Among them, the graphene layer 2 plays a better conductive role on the surface and inside of the nickel metal. The graphene layer 2 also has the function of isolating the copper substrate 1 and the nickel metal to prevent the mutual melting of copper and nickel from affecting the conductivity. The nickel layer 4 covering the outermost layer can wrap the mixed layer 3 with graphene inside, avoiding burning out in a complex application environment. At the same time, the nickel layer 4 is melted with the nickel metal in the mixed layer 3 and has a high connection strength, so that the nickel layer 4 is not easy to fall off. Furthermore, the internal mixed layer 3 and graphene layer 2 are not easy to fall off. Therefore, the graphene copper conductor provided by the embodiment of the present application has high conductivity, is not easy to burn out, fall off, or corrode, and has a long service life.

[0089] In some embodiments, the total number of layers of graphene in the graphene layer 2 and the mixed layer 3 is 3 - 6 layers.

[0090] In some embodiments, the mixed layer 3 includes a nickel matrix 3.1 and graphene 3.2. The nickel matrix 3.1 has several pores, and the graphene 3.2 is formed inside the pores and on the surface of the nickel matrix 3.1.

[0091] The following specifically illustrates the present application through specific embodiments. The following embodiments are only partial embodiments of the present application and do not limit the present application.

[0092] Example 1

[0093] This embodiment provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. Its preparation method is as follows.

[0094] S1, coat a graphene oxide layer on the surface of the copper substrate:

[0095] S1.1, first prepare a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, and the acidity and alkalinity are neutral.

[0096] S1.2, Prepare a graphene oxide layer on the surface of the copper substrate by electrodeposition. Control the temperature of the graphene oxide solution at 32°C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, the anode, and the cathode in the solution, and control the electrode voltage at 28 V to enable the electrodeposition of graphene oxide on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide and the thickness of the graphene oxide layer is 10 μm.

[0097] S2, Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0098] S2.1, Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0099] S2.2, Control the temperature of the plating solution at 50°C, the pH value of the plating solution at 5.5, and control the current density at 5 A / dm 2 , enabling the co-electrodeposition of nickel and graphene oxide on the surface of the graphene oxide layer formed in step S1 and forming a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm.

[0100] S3, Heat and reduce graphene oxide in a vacuum chamber:

[0101] S3.1, Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the surface moisture.

[0102] S3.2, Maintain the vacuum condition, increase the temperature to 500°C at a first heating rate of 10°C / min, then increase the temperature to 1000°C at a second heating rate of 20°C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, enabling the carbon dioxide and water generated by the reduction of graphene oxide to be discharged from the nickel substrate and enabling the graphene generated by the reduction of graphene oxide to melt into the nickel substrate.

[0103] S4, Re-precipitate graphene:

[0104] Cool down at a set cooling rate of 10°C / min to enable the graphene melted into the nickel metal to re-precipitate, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, thereby enabling the surface of the nickel substrate to have a graphene layer isolating the copper substrate and having graphene inside the nickel substrate to form a mixed layer of nickel and graphene.

[0105] S5, Coat a nickel layer on the surface of the mixed layer:

[0106] S5.1 Configure a plating solution for preparing a nickel layer. The plating solution for preparing the nickel layer includes nickel chloride at a concentration of 15 g / L, nickel sulfamate at 350 g / L, boric acid at 30 g / L, and phosphomolybdic acid at 20 g / L.

[0107] S5.2 Control the temperature of the plating solution for preparing the nickel layer to 50 °C, the pH value to 4.5, and control the current density to 5 A / dm² for electroplating deposition, so that the entire surface of the nickel-metal coated mixed layer is covered to form a nickel layer.

[0108] Example 2

[0109] This example provides a graphene copper conductor, which successively includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0110] S1. Coating a graphene oxide layer on the surface of the copper substrate:

[0111] S1.1 First, configure a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, the acidity and alkalinity are neutral, and 0.3 mg / L of copper oxide is added to the graphene oxide solution.

[0112] S1.2 Prepare a graphene oxide layer on the surface of the copper substrate by electroplating. Control the temperature of the graphene oxide solution to 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage to 28 V, so that the graphene oxide is electroplated on the surface of the copper substrate, ensuring that the entire surface of the copper substrate is covered by the graphene oxide, and the thickness of the graphene oxide layer is 10 μm.

[0113] S2. Coating a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0114] S2.1 Configure a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0115] S2.2 Control the temperature of the plating solution to 50 °C, the pH value of the plating solution to 5.5, and control the current density to 5 A / dm 2 , so that nickel and graphene oxide are co-electroplated on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm is formed.

[0116] S3. Heat and reduce the graphene oxide in a vacuum chamber:

[0117] S3.1 Vacuum-dry the copper substrate with a pre-mixed layer coated with graphene oxide layer, nickel, and graphene oxide to remove the moisture on the surface.

[0118] S3.2 Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide is melted into the nickel substrate.

[0119] S4, Re-precipitate graphene:

[0120] Cool down at a set cooling rate of 10 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, and thus a graphene layer that isolates the copper substrate is formed on the surface of the nickel substrate, and a mixed layer of nickel and graphene is formed inside the nickel substrate with graphene.

[0121] S5, Coat a nickel layer on the surface of the mixed layer:

[0122] S5.1 Prepare a plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0123] S5.2 Control the temperature of the plating solution for preparing the nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm2 for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0124] Example 3

[0125] This example provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0126] S1, Coat a graphene oxide layer on the surface of the copper substrate:

[0127] S1.1, First prepare a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, the acidity and alkalinity are neutral, and 0.5 mg / L of silver oxide is added to the graphene oxide solution.

[0128] S1.2, Prepare a graphene oxide layer on the surface of the copper substrate by electrodeposition. Control the temperature of the graphene oxide solution at 32°C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage at 28 V to deposit graphene oxide on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide and the thickness of the graphene oxide layer is 10 μm.

[0129] S2, Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0130] S2.1, Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0131] S2.2, Control the temperature of the plating solution at 50°C and the pH value of the plating solution at 5.5. Control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1 and form a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm.

[0132] S3, Heat and reduce graphene oxide in a vacuum chamber:

[0133] S3.1, Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0134] S3.2, Maintain the vacuum condition, increase the temperature to 500°C at a first heating rate of 10°C / min, then increase the temperature to 1000°C at a second heating rate of 20°C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate and the graphene generated by the reduction of graphene oxide melts into the nickel substrate.

[0135] S4, Re-precipitate graphene:

[0136] Cool down at a set cooling rate of 10°C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, and thus a graphene layer that isolates the copper substrate is formed on the surface of the nickel substrate and a mixed layer of nickel and graphene is formed inside the nickel substrate.

[0137] S5, Coat a nickel layer on the surface of the mixed layer:

[0138] S5.1 Configure a plating solution for preparing a nickel layer. The plating solution for preparing the nickel layer includes nickel chloride at a concentration of 15 g / L, nickel sulfamate at 350 g / L, boric acid at 30 g / L, and phosphomolybdic acid at 20 g / L.

[0139] S5.2 Control the temperature of the plating solution for preparing the nickel layer to 50 °C, the pH value to 4.5, and control the current density to 5 A / dm2 for electroplating deposition, so that the entire surface of the nickel-metal coated mixed layer is covered to form a nickel layer.

[0140] Example 4

[0141] This example provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0142] S1. Coat a graphene oxide layer on the surface of the copper substrate:

[0143] S1.1 First, configure a graphene oxide solution with a concentration of 3.5 mg / L and a neutral acid-base property.

[0144] S1.2 Prepare a graphene oxide layer on the surface of the copper substrate by electroplating. Control the temperature of the graphene oxide solution to 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage to 28 v, so that graphene oxide is electroplated on the surface of the copper substrate, ensuring that the entire surface of the copper substrate is covered by graphene oxide, and the thickness of the graphene oxide layer is 18 μm.

[0145] S2. Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0146] S2.1 Configure a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0147] S2.2 Control the temperature of the plating solution to 50 °C, the pH value of the plating solution to 5.5, and control the current density to 5 A / dm 2 , so that nickel and graphene oxide are co-electroplated on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm is formed.

[0148] S3. Heat and reduce graphene oxide in a vacuum chamber:

[0149] S3.1 Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0150] S3.2 Maintain a vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel matrix, and the graphene generated by the reduction of graphene oxide is melted into the nickel matrix.

[0151] S4. Re-precipitate graphene:

[0152] Cool down at a set cooling rate of 10 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel matrix, so that the surface of the nickel matrix has a graphene layer that isolates the copper matrix, and there is graphene inside the nickel matrix to form a mixed layer of nickel and graphene.

[0153] S5. Coat a nickel layer on the surface of the mixed layer:

[0154] S5.1 Prepare a plating solution for preparing a nickel layer. The plating solution for preparing a nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0155] S5.2 Control the temperature of the plating solution for preparing a nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm2 for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0156] Example 5

[0157] This example provides a graphene copper conductor, which sequentially includes a copper matrix, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0158] S1. Coat a graphene oxide layer on the surface of the copper matrix:

[0159] S1.1 First, prepare a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, and the acidity and alkalinity are neutral.

[0160] S1.2 Prepare a graphene oxide layer on the surface of the copper matrix by electro-deposition. Control the temperature of the graphene oxide solution to be 32 °C, connect the electrical contact conductor with a metal coating to the anode, immerse the copper matrix, anode, and cathode in the solution, control the electrode voltage to be 28 v, so that graphene oxide is electro-deposited on the surface of the copper matrix, and ensure that the surface of the copper matrix is completely coated with graphene oxide, and the thickness of the graphene oxide layer is 5 μm.

[0161] S2. Coating the surface of the graphene oxide layer with a pre-mixed layer of nickel and graphene oxide:

[0162] S2.1. Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0163] S2.2. Control the temperature of the plating solution at 50 °C, the pH value of the plating solution at 5.5, and control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm is formed.

[0164] S3. Heat and reduce graphene oxide in a vacuum chamber:

[0165] S3.1. Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0166] S3.2. Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide is melted into the nickel substrate.

[0167] S4. Re-precipitate graphene:

[0168] Cool down at a set cooling rate of 10 °C / min, so that the graphene melted into the nickel metal re-precipitates, so that 3-6 layers of graphene layers are formed on the surface and inside of the nickel substrate, and thus a graphene layer that isolates the copper substrate is formed on the surface of the nickel substrate, and a mixed layer of nickel and graphene is formed inside the nickel substrate with graphene.

[0169] S5. Coating the surface of the mixed layer with a nickel layer:

[0170] S5.1. Prepare a plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes 15 g / L of nickel chloride, 350 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0171] S5.2. Control the temperature of the plating solution for preparing the nickel layer at 50 °C, the pH value at 4.5, and control the current density at 5 A / dm2 for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0172] Example 6

[0173] This example provides a graphene copper conductor, which sequentially includes a copper matrix, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0174] S1. Coating a graphene oxide layer on the surface of the copper matrix:

[0175] S1.1. First, prepare a graphene oxide solution with a concentration of 3.5 mg / L and a neutral pH.

[0176] S1.2. Prepare a graphene oxide layer on the surface of the copper matrix by electrodeposition. Control the temperature of the graphene oxide solution at 32 °C. Connect the electrical contact conductor with a metal coating to the anode, immerse the copper matrix, anode, and cathode in the solution, and control the electrode voltage at 28 V, so that graphene oxide is electrodeposited on the surface of the copper matrix, ensuring that the surface of the copper matrix is completely coated with graphene oxide, and the thickness of the graphene oxide layer is 10 μm.

[0177] S2. Coating a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0178] S2.1. Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0179] S2.2. Control the temperature of the plating solution at 50 °C and the pH value of the plating solution at 5.5. Control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 170 μm is formed.

[0180] S3. Heat and reduce graphene oxide in a vacuum chamber:

[0181] S3.1. Vacuum-dry the copper matrix coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0182] S3.2. Maintain the vacuum condition. Increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel matrix, and the graphene generated by the reduction of graphene oxide is melted into the nickel matrix.

[0183] S4, Re-precipitate graphene:

[0184] Cool down at a set cooling rate of 10 °C / min, so that the graphene melted into the nickel metal re-precipitates, forming 3 - 6 layers of graphene layers on the surface and inside of the nickel matrix, thereby making the surface of the nickel matrix have a graphene layer isolating the copper matrix, and having graphene inside the nickel matrix to form a mixed layer of nickel and graphene.

[0185] S5, Coat a nickel layer on the surface of the mixed layer:

[0186] S5.1 Configure the plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0187] S5.2 Control the temperature of the plating solution for preparing the nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm2 for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0188] Example 7

[0189] This example provides a graphene copper conductor, which sequentially includes a copper matrix, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0190] S1, Coat a graphene oxide layer on the surface of the copper matrix:

[0191] S1.1, First configure the graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, and the acidity and alkalinity are neutral.

[0192] S1.2, Prepare the graphene oxide layer on the surface of the copper matrix by electro-deposition. Control the temperature of the graphene oxide solution to be 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper matrix, the anode, and the cathode in the solution, control the electrode voltage to be 28 v, so that the graphene oxide is electro-deposited on the surface of the copper matrix, and ensure that the surface of the copper matrix is completely coated with graphene oxide, and the thickness of the graphene oxide layer is 10 μm.

[0193] S2, Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0194] S2.1, Configure the plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0195] S2.2, control the temperature of the plating solution at 50 °C, the pH value of the plating solution at 5.5, and control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 40 μm is formed.

[0196] S3, heat and reduce graphene oxide in a vacuum chamber:

[0197] S3.1 Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0198] S3.2 Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide melts into the nickel substrate.

[0199] S4, re-precipitate graphene:

[0200] Cool down at a set cooling rate of 10 °C / min, so that the graphene melted into the nickel metal re-precipitates, so that 3-6 layers of graphene layers are formed on the surface and inside of the nickel substrate, and thus a graphene layer that isolates the copper substrate is formed on the surface of the nickel substrate, and a mixed layer of nickel and graphene is formed inside the nickel substrate with graphene.

[0201] S5, coat a nickel layer on the surface of the mixed layer:

[0202] S5.1 Prepare a plating solution for preparing a nickel layer. The plating solution for preparing a nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0203] S5.2 Control the temperature of the plating solution for preparing the nickel layer at 50 °C, the pH value at 4.5, and control the current density at 5 A / dm2 for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0204] Example 8

[0205] This example provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0206] S1, coat a graphene oxide layer on the surface of the copper substrate:

[0207] S1.1. First, prepare a graphene oxide solution with a concentration of 3.5 mg / L and a neutral pH.

[0208] S1.2. Prepare a graphene oxide layer on the surface of the copper substrate by electrodeposition. Control the temperature of the graphene oxide solution at 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage at 28 V to deposit graphene oxide on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide and the thickness of the graphene oxide layer is 10 μm.

[0209] S2. Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0210] S2.1. Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0211] S2.2. Control the temperature of the plating solution at 50 °C and the pH value of the plating solution at 5.5. Control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1 to form a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm.

[0212] S3. Heat and reduce graphene oxide in a vacuum chamber:

[0213] S3.1. Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0214] S3.2. Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 900 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide melts into the nickel substrate.

[0215] S4. Re-precipitate graphene:

[0216] Cool down at a set cooling rate of 10 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, so that the surface of the nickel substrate has a graphene layer isolating the copper substrate, and there is graphene inside the nickel substrate to form a mixed layer of nickel and graphene.

[0217] S5. Coating the surface of the mixed layer with a nickel layer:

[0218] S5.1 Prepare a plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0219] S5.2 Control the temperature of the plating solution for preparing the nickel layer to 50 °C, the pH value to 4.5, and control the current density to 5 A / dm² for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0220] Example 9

[0221] This example provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0222] S1. Coating the surface of the copper substrate with a graphene oxide layer:

[0223] S1.1 First, prepare a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, and the acidity and alkalinity are neutral.

[0224] S1.2 Prepare a graphene oxide layer on the surface of the copper substrate by electroplating. Control the temperature of the graphene oxide solution to 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage to 28 V, so that the graphene oxide is electroplated on the surface of the copper substrate, ensuring that the entire surface of the copper substrate is coated with graphene oxide, and the thickness of the graphene oxide layer is 10 μm.

[0225] S2. Coating the surface of the graphene oxide layer with a pre-mixed layer of nickel and graphene oxide:

[0226] S2.1 Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0227] S2.2 Control the temperature of the plating solution to 50 °C, the pH value of the plating solution to 5.5, and control the current density to 5 A / dm 2 , so that nickel and graphene oxide are co-electroplated on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 100 μm is formed.

[0228] S3. Heat and reduce the graphene oxide in a vacuum chamber:

[0229] S3.1 Vacuum-dry the copper substrate with a pre-mixed layer coated with a graphene oxide layer, nickel, and a graphene oxide layer to remove the moisture on the surface.

[0230] S3.2 Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1050 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide is melted into the nickel substrate.

[0231] S4. Re-precipitate graphene:

[0232] Cool down at a set cooling rate of 10 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, thereby making the surface of the nickel substrate have a graphene layer that isolates the copper substrate, and having graphene inside the nickel substrate to form a mixed layer of nickel and graphene.

[0233] S5. Coat a nickel layer on the surface of the mixed layer:

[0234] S5.1 Prepare a plating solution for preparing a nickel layer. The plating solution for preparing a nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0235] S5.2 Control the temperature of the plating solution for preparing a nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm2 for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0236] Example 10

[0237] This example provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0238] S1. Coat a graphene oxide layer on the surface of the copper substrate:

[0239] S1.1 First, prepare a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, and the acidity and alkalinity are neutral.

[0240] S1.2, Prepare a graphene oxide layer on the surface of the copper substrate by electrodeposition. Control the temperature of the graphene oxide solution at 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage at 28 V so that graphene oxide is electrodeposited on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide and the thickness of the graphene oxide layer is 10 μm.

[0241] S2, Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0242] S2.1, Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0243] S2.2, Control the temperature of the plating solution at 50 °C, the pH value of the plating solution at 5.5, and control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1 and form a pre-mixed layer composed of nickel and graphene oxide with a thickness of 170 μm.

[0244] S3, Heat and reduce graphene oxide in a vacuum chamber:

[0245] S3.1, Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0246] S3.2, Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide melts into the nickel substrate.

[0247] S4, Re-precipitate graphene:

[0248] Cool down at a set cooling rate of 15 °C / min so that the graphene melted into the nickel metal re-precipitates, forming 3 - 6 layers of graphene layers on the surface and inside of the nickel substrate, so that the surface of the nickel substrate has a graphene layer isolating the copper substrate, and there is graphene inside the nickel substrate to form a mixed layer of nickel and graphene.

[0249] S5, Coat a nickel layer on the surface of the mixed layer:

[0250] S5.1 Configure a plating solution for preparing a nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0251] S5.2 Control the temperature of the plating solution for preparing the nickel layer to 50 °C, the pH value to 4.5, and control the current density to 5 A / dm2 for electroplating deposition, so that the entire surface of the nickel-metal coated mixed layer is covered to form a nickel layer.

[0252] Example 11

[0253] This example provides a graphene copper conductor, which sequentially includes a copper substrate, a graphene layer, a mixed layer of nickel and graphene, and a nickel layer from the inside to the outside. The preparation method is as follows.

[0254] S1. Coat a graphene oxide layer on the surface of the copper substrate:

[0255] S1.1 First, configure a graphene oxide solution with a concentration of 3.5 mg / L and a neutral pH.

[0256] S1.2 Prepare a graphene oxide layer on the surface of the copper substrate by electroplating. Control the temperature of the graphene oxide solution to 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage to 28 V, so that graphene oxide is electroplated on the surface of the copper substrate, and ensure that the surface of the copper substrate is completely covered by graphene oxide, and the thickness of the graphene oxide layer is 10 μm.

[0257] S2. Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0258] S2.1 Configure a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0259] S2.2 Control the temperature of the plating solution to 50 °C, the pH value of the plating solution to 5.5, and control the current density to 5 A / dm 2 , so that nickel and graphene oxide are co-electroplated on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 170 μm is formed.

[0260] S3. Heat and reduce graphene oxide in a vacuum chamber:

[0261] S3.1 Vacuum-dry the copper substrate coated with the graphene oxide layer and the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0262] S3.2 Maintain a vacuum condition, raise the temperature to 500 °C at a first heating rate of 10 °C / min, then raise the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel matrix, and the graphene generated by the reduction of graphene oxide is melted into the nickel matrix.

[0263] S4. Re-precipitate graphene:

[0264] Cool down at a set cooling rate of 8 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel matrix, thereby enabling the surface of the nickel matrix to have a graphene layer that isolates the copper matrix, and having graphene inside the nickel matrix to form a mixed layer of nickel and graphene.

[0265] S5. Coat a nickel layer on the surface of the mixed layer:

[0266] S5.1 Prepare a plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0267] S5.2 Control the temperature of the plating solution for preparing the nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm² for electroplating deposition, so that the nickel metal coats the entire surface of the mixed layer to form a nickel layer.

[0268] Comparative Example 1

[0269] The difference between Comparative Example 1 and Example 1 is that only a graphene layer is coated on the surface of the copper matrix. The graphene layer can be directly deposited on the surface of the copper matrix by an existing method, or by the method in the embodiment of the present application, first coat a graphene oxide layer on the surface of the copper matrix, and then heat and reduce the graphene oxide layer to form a graphene layer:

[0270] (1) Coat a graphene oxide layer on the surface of the copper matrix:

[0271] First, prepare a graphene oxide solution. The concentration of the graphene oxide solution is 3.5 mg / L, and the acidity and alkalinity are neutral.

[0272] A graphene oxide layer is prepared on the surface of a copper substrate by electrodeposition. The temperature of the graphene oxide solution is controlled at 32 °C. The electrical contact conductor with a metal coating is connected to the anode, and the copper substrate, anode, and cathode are immersed in the solution. The electrode voltage is controlled at 28 V so that graphene oxide is electrodeposited on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide, and the thickness of the graphene oxide layer is 10 μm.

[0273] (2) Heat and reduce graphene oxide in a vacuum chamber:

[0274] The copper substrate coated with the graphene oxide layer is vacuum dried to remove the moisture on the surface.

[0275] Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that graphene oxide is reduced to form graphene, carbon dioxide, and water. The carbon dioxide and water are discharged, and the precipitated graphene layer remains on the outer surface of the copper substrate.

[0276] (3) Cool the copper substrate and the graphene layer at a set cooling rate of 10 °C / min.

[0277] Comparative Example 2

[0278] The difference between Comparative Example 2 and Example 1 is that only a mixed layer of nickel and graphene is coated on the surface of the copper substrate. The nickel and graphene layer can be directly deposited on the surface of the copper substrate by an existing method, or by the method in the embodiment of the present application, first coating a pre-mixed layer of nickel and graphene oxide on the surface of the copper substrate, and then heating and reducing the pre-mixed layer to form a mixed layer of nickel and graphene:

[0279] (1) Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0280] Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0281] Control the temperature of the plating solution at 50 °C, the pH value of the plating solution at 5.5, and control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 170 μm is formed.

[0282] (2) Heat and reduce graphene oxide in a vacuum chamber:

[0283] Vacuum dry the copper substrate with the pre-mixed layer coated with nickel and graphene oxide to remove the moisture on the surface.

[0284] Maintain the vacuum condition, raise the temperature to 500 °C at the first heating rate of 10 °C / min, then raise the temperature to 1000 °C at the second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide is melted into the nickel substrate.

[0285] (3) Re-precipitate graphene:

[0286] Cool down at the set cooling rate of 8 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, thereby enabling the surface of the nickel substrate to have a graphene layer that isolates the copper substrate, and having graphene inside the nickel substrate to form a mixed layer of nickel and graphene.

[0287] Comparative Example 3

[0288] The difference between Comparative Example 3 and Example 1 is that only a nickel layer is coated on the surface of the copper substrate. The nickel layer can be deposited on the surface of the copper substrate by existing methods or can be deposited in the manner of the embodiments of the present application:

[0289] Prepare a plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0290] Control the temperature of the plating solution for preparing the nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm2 for electroplating deposition, so that the entire surface of the nickel metal-coated mixed layer forms a nickel layer.

[0291] Comparative Example 4

[0292] The difference between Comparative Example 4 and Example 1 is that a graphene layer and a mixed layer of nickel and graphene are sequentially coated on the surface of the copper substrate. The graphene layer and the mixed layer can be directly deposited on the surface of the copper substrate by existing methods or can be deposited in the manner of the embodiments of the present application, that is, first coat a graphene oxide layer and a pre-mixed layer of nickel and graphene oxide on the surface of the copper substrate, and then heat and reduce the graphene oxide layer to form a graphene layer and a mixed layer:

[0293] (1) Coat a graphene oxide layer on the surface of the copper substrate:

[0294] First, prepare a graphene oxide solution with a concentration of 3.5 mg / L and a neutral pH.

[0295] Prepare a graphene oxide layer on the surface of the copper substrate by electrodeposition. Control the temperature of the graphene oxide solution at 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage at 28 V so that graphene oxide is electrodeposited on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide and the thickness of the graphene oxide layer is 10 μm.

[0296] (2) Coat a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0297] Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0298] Control the temperature of the plating solution at 50 °C and the pH value of the plating solution at 5.5. Control the current density at 5 A / dm 2 so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1 to form a pre-mixed layer composed of nickel and graphene oxide with a thickness of 170 μm.

[0299] (3) Heat and reduce graphene oxide in a vacuum chamber:

[0300] Vacuum dry the copper substrate coated with the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0301] Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide melts into the nickel substrate.

[0302] (3) Re-precipitate graphene:

[0303] Cool down at a set cooling rate of 8 °C / min to re-precipitate the graphene melted into the nickel metal, so that 3 - 6 layers of graphene layers are formed on the surface and inside of the nickel substrate, so that there is a graphene layer on the surface of the nickel substrate that isolates the copper substrate, and there is graphene inside the nickel substrate to form a mixed layer of nickel and graphene.

[0304] Comparative Example 5

[0305] The difference between Comparative Example 5 and Example 1 is that a graphene layer and a nickel layer are sequentially coated on the surface of the copper substrate. The graphene layer and the nickel layer can be directly deposited on the surface of the copper substrate by existing methods, or can be deposited in the manner of the embodiments of the present application. First, a graphene oxide layer is coated on the surface of the copper substrate, and then the graphene oxide layer is heated and reduced to form a graphene layer, and then the nickel layer is electroplated on the graphene layer:

[0306] (1) Coating a graphene oxide layer on the surface of the copper substrate:

[0307] First, prepare a graphene oxide solution with a concentration of 3.5 mg / L and a neutral pH.

[0308] Prepare a graphene oxide layer on the surface of the copper substrate by electroplating. Control the temperature of the graphene oxide solution at 32 °C. Connect the electrical contact conductor with the metal coating to the anode, immerse the copper substrate, anode, and cathode in the solution, and control the electrode voltage at 28 V to electroplate graphene oxide on the surface of the copper substrate, ensuring that the surface of the copper substrate is completely coated with graphene oxide and the thickness of the graphene oxide layer is 10 μm.

[0309] (2) Heating and reducing graphene oxide in a vacuum chamber:

[0310] Vacuum-dry the copper substrate coated with the graphene oxide layer to remove the surface moisture.

[0311] Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min to reduce graphene oxide to generate graphene, carbon dioxide, and water. The carbon dioxide and water are discharged, and the precipitated graphene layer remains on the outer surface of the copper substrate.

[0312] (3) Cooling the copper substrate and the graphene layer at a set cooling rate of 10 °C / min.

[0313] (4) Coating a nickel layer on the surface of the mixed layer:

[0314] Prepare a plating solution for preparing the nickel layer. The plating solution for preparing the nickel layer includes nickel chloride with a concentration of 15 g / L, nickel sulfamate with a concentration of 350 g / L, boric acid with a concentration of 30 g / L, and phosphomolybdic acid with a concentration of 20 g / L.

[0315] Control the temperature of the plating solution for preparing the nickel layer at 50 °C, the pH value at 4.5, and control the current density at 5 A / dm2 for electroplating deposition to coat the entire surface of the mixed layer with nickel metal to form a nickel layer.

[0316] Comparative Example 6

[0317] The difference between Comparative Example 6 and Example 1 is that a mixed layer of nickel and graphene and a nickel layer are sequentially coated on the surface of the copper substrate. Similarly, the mixed layer of nickel and graphene and the nickel layer can be directly formed on the surface of the copper substrate by the existing method, or the method in the embodiment of the present application can be adopted, that is, a pre-mixed layer of nickel and graphene oxide is first coated on the surface of the copper substrate, and then the pre-mixed layer is heated and reduced to form a mixed layer of nickel and graphene, and then the nickel layer is electrodeposited on the graphene layer:

[0318] (1) Coating a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer:

[0319] Prepare a plating solution for preparing the pre-mixed layer of nickel and graphene oxide. The plating solution includes 1.5 g / L of graphene oxide, 15 g / L of nickel chloride, 360 g / L of nickel sulfamate, 30 g / L of boric acid, and 20 g / L of phosphomolybdic acid.

[0320] Control the temperature of the plating solution at 50 °C, the pH value of the plating solution at 5.5, and control the current density at 5 A / dm 2 , so that nickel and graphene oxide are co-electrodeposited on the surface of the graphene oxide layer formed in step S1, and a pre-mixed layer composed of nickel and graphene oxide with a thickness of 170 μm is formed.

[0321] (2) Heating and reducing graphene oxide in a vacuum chamber:

[0322] Vacuum-dry the copper substrate coated with the pre-mixed layer of nickel and graphene oxide to remove the moisture on the surface.

[0323] Maintain the vacuum condition, increase the temperature to 500 °C at a first heating rate of 10 °C / min, then increase the temperature to 1000 °C at a second heating rate of 20 °C / min, and then introduce a mixed gas of hydrogen and nitrogen to increase the internal pressure of the vacuum chamber to 25 MPa and maintain it for 45 min, so that the carbon dioxide and water generated by the reduction of graphene oxide are discharged from the nickel substrate, and the graphene generated by the reduction of graphene oxide melts into the nickel substrate.

[0324] (3) Re-precipitating graphene:

[0325] Cool down at a set cooling rate of 8 °C / min, so that the graphene melted into the nickel metal re-precipitates, so that 3-6 layers of graphene layers are formed on the surface and inside of the nickel substrate, and thus a graphene layer that isolates the copper substrate is formed on the surface of the nickel substrate, and graphene is present inside the nickel substrate to form a mixed layer of nickel and graphene.

[0326] (4) Coating a nickel layer on the surface of the mixed layer:

[0327] Prepare a plating solution for preparing a nickel layer. The plating solution for preparing a nickel layer includes nickel chloride at a concentration of 15 g / L, nickel sulfamate at 350 g / L, boric acid at 30 g / L, and phosphomolybdic acid at 20 g / L.

[0328] Control the temperature of the plating solution for preparing the nickel layer to be 50 °C, the pH value to be 4.5, and control the current density to be 5 A / dm2 for electroplating deposition, so that the entire surface of the nickel metal-coated mixed layer is formed with a nickel layer.

[0329] Optionally, in the above embodiments and comparative examples, the thickness of the nickel layer is 6 μm.

[0330] Perform salt spray tests and conductivity (IACS%) tests on Examples 1-11 and Comparative Examples 1-6, and summarize the test results in Table 1. Among them, the duration of the salt spray test is the duration when corrosion spreads to the surface of the copper substrate.

[0331] Table 1

[0332]

[0333]

[0334] As can be seen from Table 1:

[0335] Compared with Comparative Examples 1, 2, and 3, Examples 1-11 showed a longer salt spray test duration, and at the same time were able to maintain a relatively high conductivity, indicating that the graphene copper substrate composite structure provided by the embodiments of the present application has better corrosion resistance and conductivity than the single plating layer structure. The technical solution of the embodiments of the present application can make the surface plating layer of the graphene copper conductor denser, not easily corroded and peeled off, and at the same time not easily inter-melt with the copper substrate to reduce conductivity. Moreover, the graphene tightly covering the surface of the copper substrate also has a certain effect of improving conductivity, so that the graphene copper conductor of the embodiments of the present application can balance a relatively high service life and conductivity.

[0336] Compared with Comparative Example 4, Examples 1-11 showed a longer salt spray test duration; compared with Comparative Example 5, the increase in the salt spray test duration was even more significant; compared with Comparative Example 6, Examples 1-11 showed a higher conductivity. It can be seen that the graphene copper substrate composite structure provided by the embodiments of the present application is superior to the two-layer combined plating layer structure in at least one of the corrosion resistance and conductivity performance.

[0337] Comparing Example 1 with Examples 2 and 3 shows that adding copper oxide or silver oxide to the graphene oxide mixed solution has a certain improvement in the firmness of the composite structure plating layer on the copper substrate, and at the same time the conductivity performance can also be maintained within a relatively high range, equivalent to or slightly higher than the conductivity of the pure copper substrate (the value is about 106).

[0338] Comparing Example 1 with Examples 4 and 5 shows that the thickness of the graphene layer (or rather, the thickness of the prepared graphene oxide layer) can be flexibly adjusted within a certain range; comparing Example 1 with Examples 6 and 7 shows that the thickness of the mixed layer of nickel and graphene (or rather, the thickness of the pre-mixed layer of prepared nickel and graphene oxide) can be flexibly adjusted within a certain range; comparing Example 1 with Examples 8 and 9 shows that the temperature for heating and reducing graphene oxide can be flexibly adjusted within a certain range; comparing Example 1 with Examples 10 and 11 shows that the set cooling rate for re-precipitating graphene can be flexibly adjusted within a certain range. That is to say, under the inventive concept of this application, adjusting the above specific data within a certain range can enable the graphene copper conductor to maintain a high conductivity and take into account a long service life.

[0339] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A preparation method of a graphene copper conductor, characterized in that, it includes: S1: Coating a graphene oxide layer on the surface of a copper substrate; S2: Coating a pre-mixed layer of nickel and graphene oxide on the surface of the graphene oxide layer; S3: Performing a heat treatment to reduce the graphene oxide in the graphene oxide layer and the pre-mixed layer to form graphene, and melting the graphene into nickel metal; S4: Cooling at a set cooling rate to precipitate the graphene melted into the nickel metal to form a graphene layer, a mixed layer of nickel and graphene; S5: Coating a nickel layer on the surface of the mixed layer.

2. The preparation method of a graphene copper conductor according to claim 1, characterized in that, before performing the heat treatment in step S3, vacuum drying is first performed.

3. The preparation method of a graphene copper conductor according to claim 1, characterized in that, in step S3, the heat treatment is performed under a vacuum condition and a pressure of 20 - 30 MPa.

4. The preparation method of a graphene copper conductor according to claim 3, characterized in that, in step S3, the temperature is first raised to 850 - 1050 °C, and then pressurized.

5. The preparation method of a graphene copper conductor according to claim 4, characterized in that, in step S3, the temperature is first raised to 500 °C at a first heating rate, and then raised to the set temperature at a second heating rate and maintained for 40 - 50 min, wherein the first heating rate is less than the second heating rate.

6. The preparation method of a graphene copper conductor according to claim 5, characterized in that, the first heating rate is 10 °C / min, and the second heating rate is 20 °C / min.

7. The preparation method of a graphene copper conductor according to claim 3, characterized in that, in step S3, pressurization is performed by injecting a mixed gas, and the mixed gas is a mixture of hydrogen and an inert gas.

8. The preparation method of a graphene copper conductor according to claim 1, characterized in that, in step S4, the set cooling rate is 8 - 20 °C / min.

9. The preparation method of a graphene copper conductor according to claim 1, characterized in that, in step S1, a graphene oxide solution is prepared, and the copper substrate is immersed in the graphene oxide solution for electroplating deposition of graphene oxide; the graphene oxide solution is configured to contain copper oxide and / or silver oxide.

10. The preparation method of a graphene copper conductor according to claim 9, characterized in that, the content of copper oxide is 0.3 - 1.5 mg / L, and the content of silver oxide is 0.3 - 1.2 mg / L.

11. The preparation method of a graphene copper conductor according to claim 1, characterized in that, In step S2, a pre-mixed layer of nickel and graphene oxide is prepared on the surface of the graphene oxide layer by electroplating. The plating solution for preparing the pre-mixed layer includes 1.2 - 3.5 g / L of graphene oxide, 12 - 20 g / L of nickel chloride, 340 - 380 g / L of nickel sulfamate, 20 - 45 g / L of boric acid, and 10 - 30 g / L of phosphomolybdic acid; The temperature of the plating solution for preparing the pre-mixed layer is 35 - 50 °C, the pH value is 5 - 5.5, and the current density is controlled at 4.5 - 5 A / dm 2 .

12. A method for preparing a graphene copper conductor according to claim 1, characterized in that, In step S5, a nickel layer is prepared on the surface of the mixed layer by electroplating. The plating solution for preparing the nickel layer includes 12 - 20 g / L of nickel chloride, 340 - 380 g / L of nickel sulfamate, 20 - 45 g / L of boric acid, and 10 - 30 g / L of phosphomolybdic acid. The temperature of the plating solution for preparing the nickel layer is 35 - 50 °C, the pH value is 3 - 4.5, and the current density is controlled to be 4.5 - 5 A / dm 2 .

13. A method for preparing a graphene copper conductor according to claim 1, characterized in that, In step S1, a graphene oxide layer with a thickness of 0.5 - 20 μm is prepared.

14. A method for preparing a graphene copper conductor according to claim 1, characterized in that, In step S2, a pre-mixed layer of nickel and graphene oxide with a thickness of 3 - 200 μm is prepared.

15. A graphene copper conductor, characterized in that, comprises: a copper substrate; a graphene layer coated on the surface of the copper substrate; a mixed layer of nickel and graphene covering the graphene layer; a nickel layer covering the mixed layer; Alternatively, the graphene copper conductor is prepared by the method for preparing a graphene copper conductor according to any one of claims 1 - 14.

16. The graphene copper conductor according to claim 15, characterized in that, the total number of graphene layers in the graphene layer and the mixed layer is 3 - 6 layers.

17. The graphene copper conductor according to claim 15, characterized in that, the mixed layer includes a nickel matrix and graphene. The nickel matrix has a number of pores, and the graphene is formed within the pores and on the surface of the nickel matrix.

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