Graphene / metal composite layer structure and preparation method and application thereof

Abstract

The application discloses a graphene / metal composite layer structure and a preparation method and application thereof. The composite layer comprises an interpenetrating network formed by mutual embedding of electroplated metal and graphene surface. Any cross section in the thickness direction of the interpenetrating network contains electroplated metal and graphene, and the average thickness ratio of the two is 4-6:5-8. The thickness of the interpenetrating network is 0.1-10 microns. The graphene dispersion liquid used in the preparation method comprises water, graphene and water-soluble conductive polymer. The water-soluble conductive polymer stabilizes the dispersion state of graphene in the graphene dispersion liquid to maintain the conductivity of the graphene dispersion liquid. The substrate comprises a surface and a hole structure recessed in the surface. The graphene-copper composite structure interface exists an interpenetrating network structure, forming a strong mechanical locking force. Since the graphene and copper interface form an interpenetrating network structure, the interface bonding strength is high, and the interface conductivity and heat conduction capacity are improved.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically, it relates to a graphene / metal composite layer structure, its preparation method, and its application. Background Technology

[0002] Currently, with the rapid development of electronic and communication technologies, commercial portable electronic products such as tablets, smartphones, and LEDs are becoming increasingly popular. However, as these electronic devices develop towards miniaturization and high density, they bring about a sharp increase in heat generation. The resulting significant heat loss leads to a decline in device performance and reliability, placing enormous pressure on thermal management. In addition to the challenges of thermal management, electromagnetic waves are also considered another critical issue that must be addressed. This is mainly because electromagnetic waves not only interfere with electronic components and devices but also have a significant impact on the environment and human health. Therefore, there is an urgent need to find a multifunctional interface material that combines excellent properties such as flexibility, ultra-high electrical and thermal conductivity, and strong electromagnetic interference shielding (EMI SE) capabilities for application in next-generation portable electronics and wearable devices.

[0003] Graphene-copper composites have attracted considerable attention from researchers in recent years. Powder metallurgy can be used to obtain composites in which graphene is dispersed in a copper matrix, but these materials exhibit poor thermal conductivity and electromagnetic shielding. One literature reports a graphene-copper composite layered structure using a high-temperature annealed graphene film as the substrate, onto which a copper layer is fabricated using magnetron sputtering, creating an overlap between the graphene and copper films. This material demonstrates excellent electromagnetic shielding. However, this method is cumbersome to prepare and difficult to scale up for widespread use.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a graphene / metal composite layer structure, its preparation method and application. A graphene dispersion is coated onto the surface of a pretreated insulating substrate to form a composite film structure with controllable morphology. The provided graphene dispersion contains a water-soluble conductive polymer, which improves the conductivity of the graphene dispersion, promotes electrocrystallization of the electroplated metal, and forms an interpenetrating network structure with the graphene conductive layer. While enhancing the bonding force between graphene and the electroplated metal, it further improves its electrical and thermal conductivity, as well as its electromagnetic shielding capability.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0007] This invention provides a graphene / metal composite layer structure, wherein the composite layer comprises an interpenetrating network formed by the interpenetrating network of electroplated metal and graphene surfaces, wherein any cross section in the thickness direction of the interpenetrating network contains electroplated metal and graphene, and the average thickness ratio of the two is 4-6:5-8, and the thickness of the interpenetrating network is 0.1-10 μm.

[0008] A further embodiment of the composite layer structure is as follows: the graphene surface is formed with a number of micropores and slits through a combination of grinding, ultrasonication and drying processes, and electroplated metal that undergoes electrocrystallization in the micropores and slits thereby interpenetrates with the graphene to form an interpenetrating network.

[0009] A further embodiment of the composite layer structure is as follows: the tensile strength of the electroplated metal in the graphene / metal composite layer is 150–350 MPa, and the electrical conductivity is 10. 6 ~10 7 The thermal conductivity is 320–650 W / mK, the electromagnetic shielding efficiency is 90–110 dB, and the tensile strength is preferably 200–350 MPa.

[0010] This invention also provides a method for preparing a graphene / metal composite layer structure, comprising:

[0011] (1) Pretreatment of the surface and / or pore structure of the insulating substrate;

[0012] (2) The prepared graphene dispersion is coated on the surface of the pretreated insulating substrate in step (1) and dried to form a conductive layer that can be used for metal electroplating.

[0013] (3) Electroplating the substrate with the conductive layer in step (2) to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal, and then removing the substrate to obtain the graphene / metal composite layer structure; or, after drying to form the conductive layer in step (2), removing the substrate first, and then electroplating the conductive layer to form an interpenetrating network structure between the graphene on both sides of the conductive layer and the electroplated metal respectively.

[0014] The graphene dispersion comprises water, graphene, and a water-soluble conductive polymer. The water-soluble conductive polymer stabilizes the dispersion state of graphene in the graphene dispersion to maintain its conductivity. The substrate comprises a surface and a porous structure recessed into the surface. The electroplating can be performed using conventional electroplating metals, preferably copper.

[0015] In the above scheme, the insulating substrate includes, but is not limited to, epoxy resin glass cloth reinforcement material, polyimide glass cloth reinforcement material, polytetrafluoroethylene glass cloth reinforcement material, polyimide film, acrylic film, hydrocarbon resin, etc. The conductivity of graphene dispersions with water as the main dispersion medium decreases slightly. Therefore, this invention introduces a water-soluble conductive polymer to give the dried graphene conductive layer stronger conductivity, which can enhance the electroplating effect of metals and facilitate the formation of electrocrystallization on the graphene surface, thereby achieving the interpenetrating intercalation of electroplated metal / graphene to obtain the interpenetrating network structure. The electroplating includes: using the conductive layer as a cathode for electroplating, with a current density of 1–10 A / dm². 2 The electroplating time is 10 to 200 minutes.

[0016] According to the above method, the graphene dispersion further includes a water-soluble polymer, wherein the mass ratio of graphene to water-soluble polymer is 1:0 to 40, preferably 1:0.01 to 5; the water-soluble polymer is selected from one or more of polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyethylene glycol, polyacrylate, polymaleic anhydride, polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyvinylphosphonic acid, polyvinylamine, and polyvinylpyridine.

[0017] In the above scheme, the conjugated system formed between the water-soluble conductive polymer and graphene improves the compatibility with subsequent composites with the water-soluble polymer. This maintains the properties of graphene within the formed conductive layer, enhances the conductivity of the conductive layer, and facilitates the formation of the electroplated metal layer. This application allows the graphene dispersion to be free of water-soluble polymers; therefore, the mass ratio of graphene to water-soluble polymers can be 1:0.

[0018] According to the above method, the graphene dispersion is prepared by the following method:

[0019] A water-soluble conductive polymer was dissolved in deionized water, and then graphene was added to the modification solution. The surface-modified graphene dispersion was obtained by physical treatment.

[0020] The physical method is selected from one or both of grinding and ultrasonic treatment;

[0021] Preferably, the method for preparing the graphene dispersion further includes: mixing a mixture obtained by physical treatment of graphene and a water-soluble conductive polymer with an aqueous solution of a water-soluble polymer to obtain the graphene dispersion.

[0022] In the above scheme, the water-soluble conductive polymer is first dissolved into a modification solution and then graphene is added. Compared with adding the binding agent and graphene to the solution at the same time, the self-aggregation effect of graphene can be avoided to a large extent, making it easier for the water-soluble conductive polymer to form non-covalent bond modification with the surface of graphene, thereby improving the dispersibility of graphene in water.

[0023] According to the above method, the average number of graphene layers in the graphene dispersion is no more than 10, preferably 1 to 5 layers.

[0024] In the above scheme, the graphene is peeled off under physical action, so that the graphene in the dispersion keeps the interlayer open. This makes the surface of the coated and dried conductive layer have several interpenetrating gaps that can form with the electroplated metal, which greatly improves the bonding strength between the electroplated metal and the conductive layer.

[0025] According to the above method, the mass ratio of graphene to water-soluble conductive polymer is 1:0.001-2, preferably 1:0.02-1; the mass fraction of graphene in the graphene dispersion is 0.05-10%, preferably 0.1-5%; the water-soluble conductive polymer includes, but is not limited to, one or more of water-soluble polyaniline, water-soluble polythiophene, and polyepoxychloropropane quaternary ammonium salt.

[0026] According to the above method, the grinding speed is 100-5000 rpm, preferably 300-1000 rpm; the grinding time is 1 min-3 h, preferably 10 min-1 h.

[0027] According to the above method, the frequency of the ultrasound is 25-100kHz, preferably 40-75kHz; the duration of the ultrasound is 30min-24h, preferably 4-12h.

[0028] According to the above method, it is preferable to perform grinding and ultrasonication simultaneously. When both are performed simultaneously, the running time of grinding and ultrasonication is selected to favor the step with the longer running time.

[0029] According to the above method, in step (2), the drying process includes: drying temperature of 40 to 120°C, drying air velocity of 0.1 to 20 m / s, drying time of 1 to 20 min, and drying air velocity of 0.1 to 20 m / s. The drying air velocity is lower in the early stage of drying, higher in the middle stage, and lower in the later stage.

[0030] In the above scheme, the drying can be carried out by forced air drying, and the initial, middle, and final stages occupy the same amount of time in the drying process. Preferably, the drying air velocity ranges from 0.1 to 5 m / s during the initial drying stage, from 7 to 20 m / s during the middle drying stage, and from 2 to 6 m / s during the final drying stage.

[0031] According to the above method, in step (1), the substrate is selected from hydrophilic materials or non-hydrophilic materials, wherein the non-hydrophilic materials are hydrophilic after pretreatment; the pretreatment includes prewashing and / or charge adjustment, and the charge adjustment includes: plasma treatment of the substrate surface and / or pore structure, treatment of the substrate surface and / or pore structure with cationic surfactants or anionic surfactants, or friction treatment of the substrate surface and / or pore structure to make the substrate surface positively or negatively charged.

[0032] In the above scheme, the friction treatment can be performed simultaneously with drilling the substrate surface.

[0033] The hydrophilic material includes, but is not limited to, polyamide, polyvinyl acetate, epoxy resin, acrylate, or composites thereof; the non-hydrophilic material includes, but is not limited to, polyimide, polycarbonate, polylactic acid, polyurethane, polycaprolactone, polymethyl methacrylate, polyhydroxyethyl methacrylate, poly(β-hydroxybutyrate), polybutylene terephthalate, polyethylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate, polystyrene, polypropylene, polyethylene, poly-1-butene, poly-4-methyl-1-pentene, or composites thereof; the substrate is preferably epoxy resin / glass fiber composite, polyimide, polyethylene terephthalate, polyimide / glass fiber composite, acrylate, etc.

[0034] When the substrate is a hydrophilic material, the pre-washing includes: ultrasonically cleaning the substrate with 1% NaOH solution and 1% Tween 20 solution for a pre-washing time of 0.5 to 5 minutes;

[0035] When the substrate is a non-hydrophilic material, the pre-washing includes: immersing the substrate in a 10% NaOH solution for 20-40 minutes, then removing it, washing off the alkaline solution, and drying it. After treatment, the substrate surface becomes a hydrophilic surface.

[0036] According to the above surface treatment method, the coating in step (2) includes immersion, scraping, or spraying; the immersion includes: immersing the substrate in an ultrasonically dispersed graphene dispersion for 5s to 5min, preferably 30 to 60s; the scraping includes: scraping a film with a thickness of 0.05 to 100μm onto the surface of the substrate to be electroplated using an ultrasonically dispersed graphene dispersion, preferably 0.1 to 10μm; the spraying includes: spraying a film with a thickness of 0.05 to 100μm onto the surface of the substrate to be electroplated using an ultrasonically dispersed graphene dispersion; preferably 0.1 to 10μm; preferably, the substrate is repeatedly scraped or sprayed multiple times; more preferably, the coating is stopped when the surface resistance of the substrate is below 100Ω, preferably below 20Ω.

[0037] In the above scheme, when the substrate itself is uneven, it is preferable to use a spraying method to coat it.

[0038] The substrate surface treatment method specifically includes the following steps:

[0039] (1) Substrate pretreatment: Pre-washing and / or charge adjustment are performed according to the material of the substrate; when the substrate is a hydrophilic material, the pre-washing includes: ultrasonic cleaning of the surface of the substrate to be electroplated with 1% NaOH solution and 1% Tween 20 solution for 0.5 to 5 minutes; when the substrate is a non-hydrophilic material, the pre-washing includes: immersing the surface of the substrate to be electroplated in 10% NaOH solution for 20 to 40 minutes, then removing it, washing off the alkali solution, and drying it; the charge adjustment includes: plasma treatment of the substrate surface, treatment of the substrate surface with cationic or anionic surfactants, or friction treatment of the substrate surface to make the substrate surface positively or negatively charged; the pretreatment makes the non-hydrophilic surface become a hydrophilic surface;

[0040] (2) Preparation of graphene dispersion: A water-soluble conductive polymer is dissolved in deionized water and treated by a physical method to obtain a graphene-modified solution. Graphene is then added to the modification solution and treated by a physical method to obtain a graphene dispersion with a graphene to water-soluble conductive polymer mass ratio of 1:0.001-2. The mass fraction of graphene in the graphene dispersion is 0.05-10%, preferably 0.1-5%. The physical method is selected from one or both of grinding and ultrasonic treatment. The grinding speed is 100-5000 rpm, preferably 1000-3000 rpm. The grinding time is 1 min-3 h, preferably 10 min-1 h. The ultrasonic frequency is 25-100 kHz, preferably 40-75 kHz. The ultrasonic time is 30 min-24 h, preferably 4-12 h.

[0041] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried to form a conductive layer. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal; or, the substrate with the conductive layer is electroplated so that the graphene in the conductive layer forms an interpenetrating network structure with the electroplated metal, and then the substrate is removed; the coating includes immersion, scraping, or spraying; the immersion includes: immersing the substrate in an ultrasonically dispersed graphene dispersion for 5s to 5min; the scraping includes: scraping a film with a thickness of 0.05 to 1mm onto the surface of the substrate to be electroplated using an ultrasonically dispersed graphene dispersion. 00 μm; preferably, the thickness of the film liquid coated by scraping is 0.1–10 μm; the spraying includes: spraying a graphene dispersion that has been ultrasonically dispersed onto the surface of the substrate to be electroplated with a film liquid thickness of 0.05–100 μm; preferably, the thickness of the sprayed film liquid is 0.1–10 μm; preferably, the substrate is repeatedly scraped or sprayed multiple times, and drying is performed between each scraping or spraying; the drying temperature is 40–100°C, the drying air velocity is 1–20 m / s, the drying time is 1–20 min, and the drying air velocity is lower in the early stage of drying, higher in the middle stage, and lower in the later stage; the electroplating includes electroplating an insulating substrate with a conductive layer as a cathode, and the electroplating current density is 3 A / dm. 2 The electroplating time is 30 minutes.

[0042] In the above-described scheme, the present invention can directly electroplate a conductive layer with an insulating substrate, and can also perform double-sided electroplating on a conductive layer after the substrate has been removed. When performing double-sided electroplating, since the conductive layer needs to be dried before peeling off the substrate, the drying process needs to be adjusted accordingly. Simultaneously, the electroplating parameters also need to be adjusted accordingly.

[0043] The present invention also provides an application of the graphene / metal composite layer structure described above in the electroplating of flexible circuit boards.

[0044] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0045] 1. The dispersion provided by the present invention uses graphene with a certain number of layers as the main raw material. The graphene layers are partially opened by physical methods. With the improvement of the drying process, the graphene coated and dried on the surface of the insulating substrate contains a large number of micropores and slits that can form interpenetration with the electroplated metal, which greatly improves the bonding strength between the electroplated metal and the conductive layer.

[0046] 2. The graphene dispersion provided by the present invention is a graphene dispersion with water as the main dispersion medium and a water-soluble conductive polymer as a dispersing aid. Compared with non-conductive dispersing aids, the graphene conductive layer after drying of the graphene dispersion using conductive polymer has better conductivity, which can enhance the electroplating effect of metals and make it easier to form electrocrystallization on the graphene surface, thereby realizing the mutual intercalation of electroplated metal / graphene to obtain the interpenetrating network structure.

[0047] 3. In the surface treatment method provided by the present invention, the solvent used to prepare the dispersion by physical means such as grinding and / or ultrasound is mainly water. At the same time, the solvent abandons the organic reagents commonly used in the prior art and mainly uses water, which is environmentally friendly, thus reducing the environmental burden of the treatment method and greatly reducing the treatment cost.

[0048] 4. The surface treatment method provided in this application offers a feasible technical solution for obtaining circuits from flexible circuit boards using additive electroplating.

[0049] 5. This application uses a graphene coating to replace a chemical plating coating. Graphene has higher electrical and thermal conductivity, which can provide a new direction for improving the performance of the circuit board itself.

[0050] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0051] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0052] Figure 1 These are schematic diagrams of the interpenetrating networks provided in Examples 1-6;

[0053] Figure 2 This is a schematic diagram of the interpenetrating network structure provided in Examples 7-13.

[0054] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise specified, copper is used as the electroplating metal in the following embodiments.

[0056] Example 1

[0057] In this embodiment, the substrate surface treatment is performed using the following method:

[0058] (1) Substrate pretreatment: The substrate is polyamide. Drill holes to achieve friction treatment on its surface. Then, use 1% NaOH solution and 1% Tween 20 solution to ultrasonically clean the surface of the substrate to be electroplated and the drilled holes. The pre-cleaning time is 0.5 min. Then take it out and dry it for later use.

[0059] (2) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polyaniline is dissolved in deionized water and ground at 2000 rpm for 10 min to obtain a modification solution. Then, graphene is added to the modification solution and ground at 3000 rpm for 1 h to obtain a mixture of graphene and water-soluble polyaniline with a mass ratio of 1:0.01. The mixture is then mixed with an aqueous solution of polyvinyl alcohol to obtain a graphene dispersion. The mass ratio of graphene to polyvinyl alcohol in the graphene dispersion is 1:0.01, and the mass fraction of graphene in the graphene dispersion is 10%.

[0060] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1), and then the substrate with the conductive layer is electroplated by drying to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal. After that, the substrate is removed to obtain the graphene / metal composite layer structure. The coating is selected from immersion, in which the substrate is immersed in an ultrasonically dispersed graphene dispersion for 5 seconds, and then taken out and dried. The drying includes: drying at 60°C with forced air for 15 minutes, with a wind speed of 0.5 m / s for the first 5 minutes, a wind speed of 7 m / s for the middle 5 minutes, and a wind speed of 2 m / s for the last 5 minutes. The electroplating includes: a current density of 1 A / dm 2 Electroplating time: 40 minutes.

[0061] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 7.4 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 4:6.

[0062] Example 2

[0063] In this embodiment, the substrate surface treatment is performed using the following method:

[0064] (1) Substrate pretreatment: The substrate is polyethylene terephthalate. Its surface is subjected to plasma treatment, and then the surface of the substrate to be electroplated is immersed in 10% NaOH solution for 20 minutes. After that, it is taken out, the alkaline solution is washed off and dried.

[0065] (2) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polythiophene was dissolved in deionized water and treated with ultrasound at 25 kHz for 30 min to obtain a modified solution. Then, graphene was added to the modified solution and treated with ultrasound at 75 kHz for 1 h to obtain a mixture of graphene and water-soluble polythiophene with a mass ratio of 1:1. The mixture was then mixed with an aqueous solution of polyvinylpyrrolidone to obtain a graphene dispersion. The mass ratio of graphene to polyvinylpyrrolidone in the graphene dispersion was 1:40, and the mass fraction of graphene in the graphene dispersion was 0.05%.

[0066] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the substrate pretreated in step (1), and then the substrate with the conductive layer is electroplated by drying to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal. After that, the substrate is removed to obtain the graphene / metal composite layer structure. The coating is selected by blade coating, using ultrasonically dispersed graphene dispersion to repeatedly blade coat the substrate surface several times. After each blade coating, it is dried, and then blade coating is repeated several times. The thickness of the film liquid coated each time is 10 μm. Finally, the desired conductive layer is obtained by drying. The drying includes: drying at 70°C for 10 min with a wind speed of 5 m / s in the first 200 s, a wind speed of 15 m / s in the middle 200 s, and a wind speed of 3 m / s in the last 200 s. The electroplating includes: a current density of 1 A / dm 2 Electroplating time: 50 minutes.

[0067] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 0.1 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 5:5.

[0068] Example 3

[0069] In this embodiment, the substrate surface treatment is performed using the following method:

[0070] (1) Substrate pretreatment: The substrate is an epoxy resin / glass fiber composite. First, it is rinsed with a high-pressure water gun to remove the surface adhering substances. Then, the surface of the substrate to be electroplated is ultrasonically cleaned with 1% NaOH solution for 5 minutes. After that, it is taken out and dried for later use.

[0071] (2) Preparation of graphene dispersion: The water-soluble conductive polymer polyepoxychloropropane quaternary ammonium salt was dissolved in deionized water, and the modified solution was obtained by grinding at 100 rpm and ultrasonic treatment at 40 kHz for 1 h. Graphene was then added to the modified solution, and the mixture was ground at 1000 rpm and ultrasonically treated at 100 kHz for 3 h. Then, it was ultrasonically treated at 100 kHz alone for 9 h to obtain a mixture of graphene and polyepoxychloropropane quaternary ammonium salt with a mass ratio of 1:0.001. The mixture was then mixed with an aqueous solution of polyethyleneimine to obtain a graphene dispersion. The mass ratio of graphene to polyethyleneimine in the graphene dispersion was 1:5, and the mass fraction of graphene in the graphene dispersion was 2%.

[0072] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the substrate pretreated in step (1), and then the substrate with the conductive layer is electroplated by drying to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal. After that, the substrate is removed to obtain the graphene / metal composite layer structure. The coating is selected from spraying. The thickness of the film liquid sprayed on the substrate surface using ultrasonically dispersed graphene dispersion is 0.5 μm. After drying, a film liquid with a thickness of 0.5 μm is sprayed again and dried. This process is repeated several times until the conductive layer is finally dried. The drying includes: drying at 80°C with forced air for 5 min, with a wind speed of 0.2 m / s in the first 100 s, a wind speed of 7 m / s in the middle 100 s, and a wind speed of 2 m / s in the last 100 s. The electroplating includes: a current density of 2 A / dm 2 Electroplating time: 40 minutes.

[0073] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 1.9 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 5:5.

[0074] Example 4

[0075] In this embodiment, the substrate surface treatment is performed using the following method:

[0076] (1) Substrate pretreatment: The substrate is polyethylene terephthalate with a surface with a pitted pore structure. The surface and pore structure of the substrate to be electroplated are immersed in 10% NaOH solution for 30 minutes, and then the substrate is taken out, the alkaline solution is washed off and dried.

[0077] (2) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polyaniline is dissolved in deionized water and ground at 100 rpm for 1 min to obtain a modification solution. Then, graphene is added to the modification solution and ground at 3000 rpm for 30 min to obtain a mixture of graphene and water-soluble polyaniline with a mass ratio of 1:0.5. The mixture is then mixed with an aqueous solution of polyethylene glycol to obtain a graphene dispersion. The mass ratio of graphene to polyethylene glycol in the graphene dispersion is 1:0.1, and the mass fraction of graphene in the graphene dispersion is 0.1%.

[0078] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1), and then the substrate with the conductive layer is electroplated by drying to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal. After that, the substrate is removed to obtain the graphene / metal composite layer structure. The coating is selected from immersion, in which the substrate is immersed in an ultrasonically dispersed graphene dispersion for 60 seconds, and then taken out and dried. The drying includes: drying at 85°C with forced air for 4 minutes, with a wind speed of 2 m / s for the first 80 seconds, a wind speed of 12 m / s for the middle 80 seconds, and a wind speed of 3 m / s for the last 80 seconds. The electroplating includes: a current density of 1.5 A / dm³. 2 Electroplating time: 30 minutes.

[0079] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 0.6 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 4:5.

[0080] Example 5

[0081] In this embodiment, the substrate surface treatment is performed using the following method:

[0082] (1) Substrate pretreatment: The substrate is polyvinyl acetate. The substrate surface is subjected to plasma treatment, and then the surface of the substrate to be electroplated is ultrasonically cleaned with 1% NaOH solution and 1% Tween 20 solution for 1 minute. After that, it is taken out and dried for later use.

[0083] (2) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polythiophene was dissolved in deionized water and treated with ultrasonic treatment at 60 kHz for 2 h to obtain a modified solution. Then, graphene was added to the modified solution and treated with ultrasonic treatment at 40 kHz for 6 h to obtain a mixed solution with a graphene water-soluble polythiophene mass ratio of 1:2. The mixed solution was then mixed with an aqueous solution of polyacrylate to obtain a graphene dispersion. The mass ratio of graphene to polyacrylate in the graphene dispersion was 1:1.2, and the mass fraction of graphene in the graphene dispersion was 0.7%.

[0084] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the substrate pretreated in step (1), and then the substrate with the conductive layer is electroplated by drying to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal. After that, the substrate is removed to obtain the graphene / metal composite layer structure. The coating is selected from blade coating, and the thickness of the film liquid coated on the substrate surface to be electroplated is 100 μm using ultrasonically dispersed graphene dispersion. After drying, a conductive layer is obtained. The drying includes: 90°C forced air drying for 3 min, with an air velocity of 0.1 m / s for the first 1 min, an air velocity of 8 m / s for the middle 1 min, and an air velocity of 2.5 m / s for the last 1 min. The electroplating includes: a current density of 7.5 A / dm. 2 The electroplating time is 10 minutes.

[0085] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 0.9 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 6:5.

[0086] Example 6

[0087] In this embodiment, the substrate surface treatment is performed using the following method:

[0088] (1) Substrate pretreatment: The substrate is polycarbonate with a concave pore structure on the surface. The surface and pore structure of the substrate are subjected to plasma treatment, and then the surface of the substrate to be electroplated is immersed in 10% NaOH solution for 40 min. After that, it is taken out, the alkaline solution is washed off and dried.

[0089] (2) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polyaniline was dissolved in deionized water and simultaneously ground at 500 rpm and ultrasonicated at 40 kHz for 1 h to obtain a modification solution. Then, graphene was added to the modification solution and simultaneously ground at 5000 rpm and ultrasonicated at 100 kHz for 3 h. After that, it was treated separately with ultrasonication at 100 kHz for 21 h to obtain a mixture of graphene and water-soluble polyaniline with a mass ratio of 1:1.5. The mixture was then further mixed with an aqueous solution of polyvinyl sulfonic acid to obtain a graphene dispersion. The mass ratio of graphene to polyvinyl sulfonic acid in the graphene dispersion was 1:0.8, and the mass fraction of graphene in the graphene dispersion was 5%.

[0090] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1), and then the substrate with the conductive layer is electroplated by drying to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal. After that, the substrate is removed to obtain the graphene / metal composite layer structure. The coating is selected from immersion, in which the substrate is immersed in an ultrasonically dispersed graphene dispersion for 5 minutes, and then taken out and dried. The drying includes: 90°C forced air drying for 15 minutes, with an air velocity of 0.1 m / s in the first 1 minute, 8 m / s in the middle 1 minute, and 2.5 m / s in the last 1 minute. The electroplating includes: a current density of 2.1 A / dm³. 2 Electroplating time: 40 minutes.

[0091] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 4.1 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 5:6.

[0092] Example 7

[0093] In this embodiment, based on Example 1, the preparation step (3) is adjusted as follows:

[0094] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating is selected from immersion. The substrate is immersed in an ultrasonically dispersed graphene dispersion for 5 seconds, and then removed and dried. The drying includes: 70°C forced air drying for 18 minutes, with a wind speed of 0.5 m / s for the first 6 minutes, a wind speed of 9 m / s for the middle 6 minutes, and a wind speed of 2.2 m / s for the last 6 minutes. The electroplating includes: a current density of 1.3 A / dm³. 2 Electroplating time: 60 minutes.

[0095] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 10 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 4:8.

[0096] Example 8

[0097] In this embodiment, based on Example 2, the preparation step (3) is adjusted as follows:

[0098] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating is selected from scraping coating. The ultrasonically dispersed graphene dispersion is repeatedly scraped onto the substrate surface several times. After each scraping coating, it is dried, and then scraped a second time and dried. This process is repeated several times. The thickness of the film liquid coated each time is 10 μm. Finally, the desired conductive layer is obtained by drying. The drying includes: 75°C forced air drying for 12 min, with an air velocity of 4.5 m / s for the first 4 min, an air velocity of 17 m / s for the middle 4 min, and an air velocity of 2.5 m / s for the last 4 min. The electroplating includes: a current density of 1.5 A / dm 2 Electroplating time: 60 minutes.

[0099] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 0.2 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 5:6.

[0100] Example 9

[0101] In this embodiment, based on Example 3, the preparation step (3) is adjusted as follows:

[0102] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating is selected from spraying. The thickness of the film liquid sprayed on the substrate surface using ultrasonically dispersed graphene dispersion is 0.5 μm. After drying, a film liquid with a thickness of 0.5 μm is sprayed again and dried. This process is repeated several times until the conductive layer is finally dried. The drying includes: drying at 90°C with forced air for 9 min, with a wind speed of 0.4 m / s for the first 3 min, a wind speed of 8 m / s for the middle 3 min, and a wind speed of 4 m / s for the last 3 min. The electroplating includes: a current density of 3 A / dm 2 Electroplating time: 45 minutes.

[0103] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 2.8 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 5:7.

[0104] Example 10

[0105] In this embodiment, based on Example 4, the preparation step (3) is adjusted as follows:

[0106] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating is selected from immersion. The substrate is immersed in an ultrasonically dispersed graphene dispersion for 60 seconds, and then removed and dried. The drying includes: 100°C forced air drying for 6 minutes, with a wind speed of 4 m / s for the first 2 minutes, a wind speed of 15 m / s for the middle 2 minutes, and a wind speed of 2 m / s for the last 2 minutes. The electroplating includes: a current density of 2 A / dm³. 2 Electroplating time: 40 minutes.

[0107] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 1.0 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 4:6.

[0108] Example 11

[0109] In this embodiment, based on Example 5, the preparation step (3) is adjusted as follows:

[0110] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating is selected from blade coating. The thickness of the film liquid coated on the substrate surface to be electroplated is 100 μm using ultrasonically dispersed graphene dispersion. After drying, the conductive layer is obtained. The drying includes: drying at 110℃ for 4.5 min with a wind speed of 0.4 m / s for the first 1.5 min, a wind speed of 12 m / s for the middle 1.5 min, and a wind speed of 6 m / s for the last 1.5 min. The electroplating includes: a current density of 10 A / dm 2 The electroplating time is 12 minutes.

[0111] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 1.5 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 6:7.

[0112] Example 12

[0113] In this embodiment, based on Example 6, the preparation step (3) is adjusted as follows:

[0114] (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the pretreated substrate in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating is selected from immersion. The substrate is immersed in an ultrasonically dispersed graphene dispersion for 5 minutes, and then removed and dried. The drying includes: drying at 120°C with forced air for 12 minutes, with a wind speed of 0.5 m / s for the first 4 minutes, a wind speed of 18 m / s for the middle 4 minutes, and a wind speed of 4 m / s for the last 4 minutes. The electroplating includes: a current density of 4.2 A / dm³. 2 Electroplating time: 38 minutes.

[0115] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 6.2 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 5:8.

[0116] Example 13

[0117] (1) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polyaniline is dissolved in deionized water and ground at 2000 rpm for 10 min to obtain a modification solution. Then, graphene is added to the modification solution and ground at 3000 rpm for 1 h to obtain a mixture of graphene and water-soluble polyaniline with a mass ratio of 1:0.01. The mixture is then mixed with an aqueous solution of polyvinyl alcohol to obtain a graphene dispersion. The mass ratio of graphene to polyvinyl alcohol in the graphene dispersion is 1:0.01, and the mass fraction of graphene in the graphene dispersion is 10%.

[0118] (2) Preparation of self-supporting film: The graphene obtained in step (2) is coated on the surface of the substrate, dried to form a film, and then the substrate is removed to obtain the graphene film; the coating is selected from immersion, the substrate is immersed in the ultrasonically dispersed graphene dispersion for 5s, and then taken out and dried; the drying includes: 60℃ forced air drying for 15min, the wind speed for the first 5min is 0.5m / s, the wind speed for the middle 5min is 7m / s, and the wind speed for the last 5min is 2m / s.

[0119] (3) Double-sided electroplating: The film obtained in (2) is placed in an electroplating solution for double-sided electroplating; the electroplating includes: a current density of 4.2 A / dm³. 2 Electroplating time: 38 minutes.

[0120] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 10 μm, and the average thickness ratio of electroplated metal to graphene in any cross section along the thickness direction of the interpenetrating network is 4:6.

[0121] Comparative Example 1

[0122] This comparative example is based on Example 1, except that the drying method in step (3) is changed to natural drying at room temperature (25°C). Other implementation methods of this comparative example are the same as in Example 1.

[0123] In this embodiment, the thickness at the interface between the electroplated metal and graphene is less than 0.03 μm, and no obvious interpenetrating network structure is formed between the two.

[0124] Comparative Example 2

[0125] This comparative example is based on Example 1, except that the drying method in step (3) is changed to drying at 60°C with a constant wind speed of 7 m / s for 15 min. Other implementation methods of this comparative example are the same as in Example 1.

[0126] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 1.3 μm. There are continuous sheets of graphene or electroplated metal in the thickness direction of the interpenetrating network. That is, there are no uniformly distributed and interlocked electroplated metal and graphene in the cross section of the thickness direction of the interpenetrating network structure.

[0127] Comparative Example 3

[0128] This comparative example is based on Example 7, except that the drying method in step (3) is changed to natural drying at room temperature (25°C). Other implementation methods of this comparative example are the same as in Example 7.

[0129] In this embodiment, the thickness at the interface between the electroplated metal and graphene is less than 0.03 μm, and no obvious interpenetrating network structure is formed between the two.

[0130] Comparative Example 4

[0131] This comparative example is based on Example 7, except that the drying method in step (3) is changed to drying at 70°C with a constant wind speed of 9 m / s for 18 min. Other implementation methods of this comparative example are the same as in Example 7.

[0132] The thickness of the metal / graphene interpenetrating network structure formed in this embodiment is 2.2 μm. There are continuous graphene or electroplated metal in the thickness direction of the interpenetrating network. That is, there are no uniformly distributed and interlocked electroplated metal and graphene in the cross section of the thickness direction of the interpenetrating network structure.

[0133] Experimental Example 1

[0134] To better illustrate the technical effects brought about by the surface treatment of this invention, the relevant performance of the interpenetrating network structures prepared in Examples 1-13 and the comparative example was tested in this experimental example. The results are shown in the table below:

[0135]

[0136] As shown in the table above, the graphene dispersion provided by this invention uses water as the main dispersion medium and a water-soluble conductive polymer as a dispersing aid. Compared with non-conductive dispersing aids, the graphene conductive layer after drying using the conductive polymer dispersion exhibits better conductivity, enhances the electroplating effect of metals, and facilitates the formation of electrocrystallization on the graphene surface, thereby achieving the interpenetrating network structure of the electroplated metal / graphene. Comparative Examples 1 and 2, based on Example 1 (single-sided electroplating) and Example 7 (double-sided electroplating), respectively, replaced the drying process with more conventional natural air drying. This prevented the graphene from forming large-scale micropores and narrow gaps during drying, resulting in a poorer bonding effect with the electroplated metal and thus affecting the performance of the prepared composite material. Comparative Examples 3 and 4, based on Example 1 (single-sided electroplating) and Example 7 (double-sided electroplating), replaced the drying process with uniform-speed forced-air drying at a higher temperature. This drying process was more stable, resulting in fewer micropores and slits formed in the graphene during drying. Consequently, the bonding effect with the electroplated metal was not ideal, affecting the relevant properties of the composite material.

[0137] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A graphene / metal composite layer structure, characterized by, The graphene / metal composite layer includes an interpenetrating network formed by the interpenetrating metal and graphene surfaces. Any cross-section of the interpenetrating network in the thickness direction contains both electroplated metal and graphene, and the average thickness ratio of the two is 4-6:5-8. The thickness of the interpenetrating network is 0.1-10 μm. The graphene surface is formed with a combination of grinding, ultrasonication, and drying processes to create a plurality of micropores and slits. Electroplated metal undergoes electrocrystallization in the micropores and slits, thereby interpenetrating with the graphene to form an interpenetrating network. The grinding speed is 100-5000 rpm; the grinding time is 1 min-3 h; the ultrasonic frequency is 25-100 kHz; and the ultrasonication time is 30 min-24 h. The drying process includes: a drying temperature of 40–120℃, a drying time of 1–20 min, a drying air velocity range of 0.1–5 m / s during the initial drying time, a drying air velocity range of 7–20 m / s during the middle drying time, and a drying air velocity range of 2–6 m / s during the later drying time. The initial, middle, and later drying times are of equal duration.

2. The graphene / metal composite layer structure according to claim 1, characterized in that, The tensile strength of the electroplated metal in the graphene / metal composite layer is 150-350 MPa, the electrical conductivity is 10 6 -10 7 S / m, the thermal conductivity is 320-650 W / m·K, and the electromagnetic shielding efficiency is 90-110 dB.

3. A method for preparing a graphene / metal composite layer structure as described in any one of claims 1 or 2, characterized in that, include: (1) Pretreatment of the surface and / or pore structure of the insulating substrate; (2) The prepared graphene dispersion is coated onto the surface of the pretreated insulating substrate in step (1) and dried to form a conductive layer that can be electroplated with metal; the coating includes scraping or spraying, and the insulating substrate is repeatedly scraped or sprayed multiple times, and drying is performed between each scraping or spraying. (3) Electroplating the substrate with the conductive layer in step (2) to form an interpenetrating network structure between the graphene in the conductive layer and the electroplated metal, and then removing the substrate to obtain the graphene / metal composite layer structure; or, after drying to form the conductive layer in step (2), removing the substrate first, and then electroplating the conductive layer to form an interpenetrating network structure between the graphene on both sides of the conductive layer and the electroplated metal respectively. The graphene dispersion comprises water, graphene, and a water-soluble conductive polymer. The water-soluble conductive polymer stabilizes the dispersion state of graphene in the graphene dispersion to maintain the conductivity of the graphene dispersion. The substrate comprises a surface and a porous structure recessed in the surface. The graphene dispersion is prepared by the following method: a water-soluble conductive polymer is dissolved in deionized water to obtain a modification solution, and then graphene is added to the modification solution. The surface-modified graphene dispersion is obtained by physical treatment. The physical method is selected from one or two of grinding and ultrasonic treatment. The graphene dispersion has an average number of graphene layers of 1 to 5 layers.

4. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The graphene dispersion further includes a water-soluble polymer, wherein the mass ratio of graphene to water-soluble polymer is 1:0 to 40; the water-soluble polymer is selected from one or more of polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine, polyethylene glycol, polyacrylate, polymaleic anhydride, polyacrylic acid, polymethacrylic acid, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyvinylphosphonic acid, polyvinylamine, and polyvinylpyridine.

5. The method for preparing the graphene / metal composite layer structure according to claim 4, characterized in that, The mass ratio of graphene to water-soluble polymer is 1:0.01 to 5.

6. The method for preparing the graphene / metal composite layer structure according to claim 4, characterized in that, The method for preparing the graphene dispersion further includes: mixing the mixture obtained by physical treatment of graphene and water-soluble conductive polymer with an aqueous solution of water-soluble polymer to obtain the graphene dispersion.

7. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The mass ratio of graphene to water-soluble conductive polymer is 1:0.001-2; the mass fraction of graphene in the graphene dispersion is 0.05-10%; the water-soluble conductive polymer is one or more of water-soluble polyaniline, water-soluble polythiophene, and polyepoxychloropropane quaternary ammonium salt.

8. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The mass ratio of graphene to water-soluble conductive polymer is 1:0.02 to 1.

9. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The mass fraction of graphene in the graphene dispersion is 0.1% to 5%.

10. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The grinding speed is 1000-3000 rpm.

11. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The grinding time is 10 minutes to 1 hour.

12. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The frequency of the ultrasound is 40–75 kHz.

13. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The duration of the ultrasound is 4 to 12 hours.

14. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, The pretreatment includes prewashing and / or charge adjustment to convert the non-hydrophilic surface into a hydrophilic surface; The charge adjustment includes: plasma treatment, cationic surfactant treatment, anionic surfactant treatment, or triboelectric treatment.

15. The method for preparing the graphene / metal composite layer structure according to claim 3, characterized in that, include: (1) Substrate pretreatment: The substrate is polyamide. Drill holes to achieve friction treatment on its surface. Then, use 1% NaOH solution and 1% Tween 20 solution to ultrasonically clean the surface of the substrate to be electroplated and the drilled holes. The pre-cleaning time is 0.5 min. Take it out and dry it. (2) Preparation of graphene dispersion: The water-soluble conductive polymer water-soluble polyaniline was dissolved in deionized water and ground at 2000 rpm for 10 min to obtain a modification solution. Then, graphene was added to the modification solution and ground at 3000 rpm for 1 h to obtain a mixture of graphene and water-soluble polyaniline with a mass ratio of 1:0.

01. The mixture was then mixed with an aqueous solution of polyvinyl alcohol to obtain a graphene dispersion. The mass ratio of graphene to polyvinyl alcohol in the graphene dispersion was 1:0.01, and the mass fraction of graphene in the graphene dispersion was 10%. (3) Forming an interpenetrating network: The graphene obtained in step (2) is coated onto the surface of the substrate that has been pretreated in step (1) and dried. After removing the substrate, the conductive layer is electroplated on both sides so that the graphene on both sides of the conductive layer forms an interpenetrating network structure with the electroplated metal. The coating process is selected from immersion, in which the substrate is immersed in an ultrasonically dispersed graphene dispersion for 5 seconds, and then removed and dried; the drying process includes: forced air drying at 70°C for 18 minutes, with an air velocity of 0.5 m / s for the first 6 minutes, an air velocity of 9 m / s for the middle 6 minutes, and an air velocity of 2.2 m / s for the last 6 minutes; the electroplating process includes: a current density of 1.3 A / dm2 and an electroplating time of 60 minutes.

16. An application of the graphene / metal composite layer structure as described in any one of claims 1 or 2 in electroplating technology.

17. The application according to claim 16, characterized in that, Used for flexible circuit boards, metallization of non-metallic surfaces, electromagnetic shielding materials, or heat dissipation materials.

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