Reduced graphene oxide-copper composite conductive coating and preparation process thereof

Abstract

The invention discloses a reduced graphene oxide-copper composite conductive coating and a preparation process thereof, and belongs to the technical field of material surface engineering. In the reduced graphene oxide-copper composite conductive coating, deposited reduced graphene oxide constructs a continuous three-dimensional network structure with macroscopic pores on a substrate through folding, stacking and mutual lap joint of sheet layers; the metal copper phase exists in a discrete nanometer form; copper particles are in tight contact with reduced graphene oxide, and no obvious gap exists; and the copper particles are partially wrapped or anchored in the network by the reduced graphene oxide sheet layer. The reduced graphene oxide-copper composite conductive coating is stable in process and excellent in performance, a long-acting, reliable and multifunctional surface protection technology is provided for key copper parts in the fields of electronics, electrics, ocean engineering and the like, and the metal-grade conductive performance is kept.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material surface engineering, and particularly relates to a reduced graphene oxide-copper composite conductive coating and a preparation process thereof. BACKGROUND

[0002] Corrosion of copper, especially in the environment containing chloride ions, can cause its conductivity to decrease and structural failure, resulting in huge economic losses. Although traditional organic coatings can provide certain protection, they are often insulating and cannot meet the needs of static electricity dissipation occasions (such as oil storage facilities, electronic components, etc.). Therefore, the development of copper protective coatings with good conductivity is a current research hotspot.

[0003] Reduced graphene oxide (rGO) has become an ideal key component due to its high specific surface area, excellent conductivity and excellent barrier property. rGO is prepared by chemical or thermal reduction of GO. This process effectively removes most of the oxygen-containing functional groups and significantly repairs the sp2 carbon skeleton, thereby increasing its electrical conductivity by several orders of magnitude compared with GO, while maintaining good processing adaptability. Copper (Cu) also has high conductivity. The reduced graphene oxide (rGO) / copper (Cu) composite coating prepared by electrocodeposition has important applications in terms of excellent mechanics, electromagnetism, catalysis and antibiosis, and has great process advantages and application potential.

[0004] However, the conductivity of the prepared reduced graphene oxide-copper coating is still unstable, and the microstructure and component distribution of the coating are difficult to accurately control, which restricts the repeatability and further improvement of its performance. SUMMARY

[0005] To solve the above technical problems, the present application provides a reduced graphene oxide-copper composite conductive coating and a preparation process thereof.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A reduced graphene oxide-copper composite conductive coating, wherein the deposited reduced graphene oxide forms a continuous three-dimensional network structure with macroscopic pores on the substrate through the folding, stacking and mutual lapping of the sheet layers; and the metal copper exists in the form of discrete nanometer copper grains; the nanometer copper grains are in close contact with the reduced graphene oxide and have no obvious gap; and the nanometer copper grains are partially wrapped or anchored in the network by the reduced graphene oxide sheet layers.

[0008] In the reduced graphene oxide-copper composite conductive coating, the reduced graphene oxide is uniformly distributed in multiple orientations, and part of the sheet layers of the reduced graphene oxide present a straight or inclined form; and the nanometer copper grains in the reduced graphene oxide-copper composite conductive coating form a fine equiaxed crystal structure.

[0009] Or, the reduced graphene oxide-copper composite conductive coating is mainly in the form of a local enrichment area, and the reduced graphene oxide-copper composite conductive coating has a non-uniform structure in which the reduced graphene oxide agglomerates coexist with copper grains.

[0010] Or, the reduced graphene oxide-copper composite conductive coating is mainly in the form of a local enrichment area, and the reduced graphene oxide-copper composite conductive coating has a non-uniform structure in which the reduced graphene oxide agglomerates coexist with copper grains.

[0011] The size of the nanometer copper grains is 10-100 nm.

[0012] The preparation process of the reduced graphene oxide-copper composite conductive coating is prepared by controlling the C / O ratio of the reduced graphene oxide, and the preparation process comprises the following steps:

[0013] The electrolyte containing copper ions and reduced graphene oxide is prepared. The copper ions are from soluble copper salts such as copper sulfate and copper chloride, and the content of copper ions and reduced graphene oxide in the electrolyte can be any value without special requirements. Preferably, the concentration of copper ions is 0.1-1.0 mol / L, and the concentration of reduced graphene oxide is 0.1-1.0 g / L.

[0014] The substrate is placed as a cathode in the electrolyte, and then an external electric field is applied.

[0015] After a certain reaction time, a reduced graphene oxide-copper composite conductive coating can be formed on the cathode.

[0016] The C / O ratio of the reduced graphene oxide is 2.9-13.

[0017] The C / O ratio of the reduced graphene oxide is 5-13.

[0018] The reduced graphene oxide is prepared at a reduction temperature of not less than 200°C.

[0019] The reduced graphene oxide is prepared at a reduction temperature of 300-700°C.

[0020] The current density of the external electric field is not less than 5 A / dm 2 The reaction time is 10 minutes to 30 minutes, preferably greater than 10 minutes and less than 30 minutes.

[0021] The electrolyte further contains polyacrylic acid, and the mass concentration of the polyacrylic acid is 0.1-0.5 mg / L.

[0022] The pH of the electrolyte is 0.8-1.2.

[0023] The beneficial effects of the present application are as follows:

[0024] (1) The present application develops a reduced graphene oxide-copper composite conductive coating with stable process and excellent performance, which provides a long-term, reliable and multifunctional surface protection technology for key copper components in the fields of electronics, marine engineering and the like, and maintains the metal-level conductivity.

[0025] (2) The reduced graphene oxide-copper composite conductive coating of the present application realizes the integrated and synergistic improvement of corrosion resistance and conductivity. By limiting the C / O ratio of the reduced graphene oxide, the present application successfully prepares a composite coating with close combination between the sheet layer of the reduced graphene oxide and the copper matrix, so that a continuous and stable three-dimensional composite network is formed. The coating significantly delays the corrosion of the matrix while maintaining excellent conductivity.

[0026] (3) The preparation process of the present application has process feasibility and environmental friendliness. The electroco-deposition process of the present application has simple equipment and short process, is easy to implement and expand production, and has good process feasibility. Compared with some gas deposition techniques, the process is carried out under near normal temperature and pressure, has low energy consumption, and is more environmentally friendly and economically practical. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The conductivity test result graph of the composite conductive coating prepared for the comparative example, embodiment 1 to embodiment 4 of the present application.

[0028] Figure 2 The XRD test result graph of the reduced graphene oxide-copper composite conductive coating prepared for embodiment 1, embodiment 2 and embodiment 4 of the present application.

[0029] Figure 3 The microstructure graph of the reduced graphene oxide-copper composite conductive coating prepared for embodiment 1 of the present application.

[0030] Figure 4 The microstructure graph of the reduced graphene oxide-copper composite conductive coating prepared for embodiment 2 of the present application.

[0031] Figure 5 The microstructure graph of the reduced graphene oxide-copper composite conductive coating prepared for embodiment 4 of the present application.

[0032] Figure 6 The XPS test result graph of the graphene oxide used in each embodiment of the present application.

[0033] Figure 7The XPS test results are shown for the reduced graphene oxide prepared in Example 2 of this invention.

[0034] Figure 8 The XPS test results are shown for the reduced graphene oxide prepared in Example 3 of this invention.

[0035] Figure 9 The image shows the XPS test results of the reduced graphene oxide prepared in Example 1 of this invention.

[0036] Figure 10 The XPS test results are shown for the reduced graphene oxide prepared in Example 4 of this invention.

[0037] Figure 11 The XPS test results are shown for the reduced graphene oxide prepared in Example 5 of this invention.

[0038] Figure 12 The XRD patterns are of the reduced graphene oxide-copper composite conductive coatings prepared in Examples 1, 6 and 7.

[0039] Figure 13 The graph shows the conductivity test results of the reduced graphene oxide-copper composite conductive coatings prepared in Examples 1, 6 and 7.

[0040] Figure 14 The XRD patterns are of the reduced graphene oxide-copper composite conductive coatings prepared in Examples 1, 8 and 9. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0042] Example 1:

[0043] Part 1: Preparation of reduced graphene oxide (rGO).

[0044] Dry graphene oxide was placed in a quartz boat within a tubular furnace, sealed, and then purged with high-purity argon for 30 minutes to replace the air. Subsequently, under argon protection, the temperature was programmed to reach the target temperature of 400°C at a rate of 5°C / min, held for 30 minutes, and then cooled to room temperature with the furnace, ultimately yielding a fluffy, black, sheet-like solid of reduced graphene oxide, which was stored in an inert atmosphere-protected container for later use. The C / O ratio of the prepared rGO was measured to be 7.28.

[0045] Part 2: Preparation of reduced graphene oxide-copper composite conductive coating (rGO / Cu composite conductive coating).

[0046] First, the copper substrate was sanded smooth with sandpaper. The smooth copper substrate was then ultrasonically cleaned sequentially with ethanol and deionized water to remove surface contaminants. The reduced graphene oxide prepared in the first part was dispersed in a copper sulfate electrolyte solution with a pH of 1 ± 0.2, and an appropriate amount of polyacrylic acid was added as a dispersant. A uniform suspension was obtained by ultrasonication with a probe for 30 minutes. In this embodiment, the copper sulfate electrolyte was a saturated copper sulfate solution, the concentration of reduced graphene oxide was 0.1 g / L, and the amount of polyacrylic acid added was 0.1 mg / L.

[0047] Under continuous stirring, the cleaned copper substrate (copper sheet) was used as the cathode, and electroco-deposition was performed in constant current mode, with the current density controlled at 8A / dm² and the deposition time at 20 minutes.

[0048] After deposition, the sample was removed, rinsed with deionized water and ethanol respectively, and dried in an oven at 50°C for 30 minutes. Finally, a dense reduced graphene oxide-copper composite conductive coating was obtained on the copper substrate surface.

[0049] Example 2:

[0050] The entire preparation process of Example 2 is the same as that of Example 1, except that the target temperature in the first part is 200°C and the C / O ratio of rGO is 2.99.

[0051] Example 3:

[0052] The entire preparation process of Example 3 is the same as that of Example 1, except that the target temperature in the first part is 300°C and the C / O ratio of rGO is 5.74.

[0053] Example 4:

[0054] The entire preparation process of Example 4 is the same as that of Example 1, except that the target temperature in the first part is 600℃ and the C / O ratio of rGO is 12.14.

[0055] Example 5:

[0056] The entire preparation process of Example 5 is the same as that of Example 1, except that the target temperature in the first part is 700℃ and the C / O ratio of rGO is 11.57.

[0057] Comparative example:

[0058] In the comparative example, no deposition process was performed on the substrate, so the conductivity of the undeposited substrate was measured.

[0059] Figure 1The graph shows the conductivity test results of the composite conductive coatings prepared in Comparative Examples 1 to 4. Figure 1 As can be seen, when the C / O ratio of reduced graphene oxide (rGO) is greater than 5, that is, when the reduction temperature is greater than or equal to 300℃, the conductivity of the composite conductive coating reaches the level of metallic conductivity.

[0060] Figure 2 The XRD patterns are shown for the reduced graphene oxide-copper composite conductive coatings prepared in Examples 1, 2, and 4. Figure 2 In the XRD patterns shown, when the C / O ratio is 7.28, the characteristic diffraction peaks of metallic Cu (such as (111) and (200)) have the highest intensity and sharpest peak shape, indicating that the Cu crystals deposited on this substrate have the best crystallinity and the most complete structure. At the same time, the pattern with a C / O ratio of 7.28 does not show obvious impurity peaks such as cuprous oxide (Cu2O), proving that the product has high purity. In contrast, rGO with a C / O ratio of 2.99 has low Cu deposition efficiency and is easily oxidized due to insufficient reduction and poor conductivity. rGO with a C / O ratio of 12.14 has better conductivity, but its surface is too inert, which may not be conducive to the uniform nucleation and dense deposition of copper ions, resulting in Cu crystal quality that is not optimal.

[0061] In addition, from Figure 2 It can be seen that the thermal reduction temperature is the key factor controlling the crystal structure of rGO. As the reduction temperature of rGO increases from 200℃ to 600℃, the (002) peak of rGO gradually becomes sharper and shifts to a higher angle. At low reduction temperatures, the reduction degree is not high, the rGO structure is disordered, the interlayer spacing is large, and there are many defects. At high reduction temperatures, the reduction is more complete, the sp² carbon network of rGO is better repaired, the interlayer spacing is reduced, and the degree of order and graphitization is higher. In all samples, the sharp copper peak dominates, which indicates that the conductive substrate of the composite material is mainly highly crystalline nano-copper. The successful composite of rGO does not destroy the crystal structure of copper, and this bonding method can effectively maintain the conductivity of the coating comparable to that of metallic copper, i.e., metallic conductivity.

[0062] Figures 3 to 5 The microstructure diagrams are of the reduced graphene oxide-copper composite conductive coatings prepared in Examples 1, 2 and 4 of this invention. Figures 3 to 5This invention reflects the common structural characteristics of the reduced graphene oxide-copper composite conductive coating prepared in this invention. The deposited reduced graphene oxide is not a flat, monolayer layer, but rather forms a continuous, macroscopically porous three-dimensional network structure on the substrate through the wrinkling, stacking, and overlapping of the sheets. This network, serving as the framework of the entire composite material, provides a large specific surface area and abundant topological defect sites. Furthermore, the formation and distribution of the dispersed phase in the composite conductive coating also exhibit certain commonalities. The metallic copper phase does not form a continuous film but exists in a discrete nanoscale form. The spatial distribution of the nano-copper exhibits significant selectivity; nano-copper particles preferentially undergo heterogeneous nucleation and growth at sites with high surface energy, such as the wrinkle edges, sheet junctions, and structural defects of the rGO network. This indicates that the Cu deposition process is regulated by the physicochemical properties of the rGO surface. Figures 3 to 5 Furthermore, the commonalities between the two-phase interface and the composite system in the composite conductive coating can be observed. The microstructure shows that the interface between Cu particles and the rGO support is tight with no obvious gaps. Many Cu particles are partially encapsulated or anchored in the network by the rGO sheets, forming a strong mechanical interlocking effect. This structure is beneficial for charge transport at the two-phase interface and can enhance the mechanical stability of the composite material.

[0063] Figure 3 This is a microstructure diagram of the reduced graphene oxide-copper composite conductive coating prepared in Example 1 of the present invention. From... Figure 3 As can be seen, in the composite conductive coating prepared in this embodiment, rGO exhibits a uniform distribution with multiple orientations, some layers exhibit an upright or tilted embedding mode, and the overall structure of the coating is dense, the copper grain size is reduced, forming a fine equiaxed crystal structure, and a tightly bonded interface is formed between the rGO layers and the copper grains, jointly constructing a continuous three-dimensional composite network.

[0064] Figure 4 This is a microstructure diagram of the reduced graphene oxide-copper composite conductive coating prepared in Example 2 of the present invention. From... Figure 4 As can be seen from the example, in the composite conductive coating prepared in Example 2, the rGO sheets are mainly embedded in the copper substrate in a flat and wrinkled manner. From the cross-sectional structure of the coating, the alternating layered configuration formed by the rGO sheets and the copper substrate can be observed. Furthermore, a composite structure with many nanoscale pores is formed at the interface between rGO and the copper substrate. This is because the presence of oxygen-containing functional groups leads to non-dense deposition.

[0065] Figure 5 This is a microstructure diagram of the reduced graphene oxide-copper composite conductive coating prepared in Example 4 of the present invention. From... Figure 5As can be seen from the results, in the composite conductive coating prepared in Example 4, rGO is mainly encapsulated in the copper substrate in the form of aggregates, forming local enrichment regions. An inhomogeneous structure in which micron-scale rGO aggregates coexist with copper grains can be observed in the coating. The copper grains grow freely and are larger in size in the regions far away from the rGO aggregates, while local grain refinement is observed around the aggregates.

[0066] The inventors further analyzed the reduced graphene oxide prepared in Examples 1 to 5, and the results are shown in [the table below]. Figures 7 to 11 .according to Figures 7 to 11 The analysis results suggest that the significant differences in the microstructure and properties of the composite conductive coatings prepared in Examples 1 to 5 are due to the different C / O ratios of the reduced graphene oxide used. As a control, the graphene oxide used was also analyzed, and the results are shown below. Figure 6 .

[0067] from Figures 6 to 11 It can be seen that as the reduction temperature increases, the C / O ratio of rGO gradually increases, indicating that its reduction degree is gradually increasing. In addition, when the reduction temperature reaches 600℃, the reduction degree no longer changes significantly.

[0068] The results show that there exists an optimal C / O ratio range in the rGO / Cu composite coating system, typically between 5 and 13. A low C / O ratio (e.g., <5) indicates insufficient rGO reduction and an excessive number of oxygen-containing functional groups. While this is beneficial for dispersion in aqueous electrolytes, its poor intrinsic conductivity may lower the overall conductivity of the composite coating. A high C / O ratio (e.g., >13) indicates highly reduced rGO, approaching graphene levels, resulting in improved intrinsic conductivity. However, this leads to strong hydrophobicity, making it prone to aggregation in the electrolyte, hindering uniform dispersion and co-deposition, ultimately forming defects in the coating and impairing its density and corrosion resistance. The optimal range (5-13) represents the best balance between the conductivity and dispersibility / processability of rGO. It can maintain a sufficiently good dispersion state to achieve uniform co-deposition, while its repaired sp² carbon network can provide excellent conductive pathways and effective barrier effects against corrosive media. Therefore, by controlling the C / O ratio of rGO within this range, the conductive and anti-corrosion properties of the composite coating can be synergistically optimized.

[0069] Example 6:

[0070] The entire preparation process in this embodiment is the same as in Example 1, except that the current density in the second part is changed. In this embodiment, the current density is 5 A / dm².

[0071] Example 7:

[0072] The entire preparation process in this embodiment is the same as in Example 1, except that the current density in the second part is changed. In this embodiment, the current density is 10 A / dm².

[0073] Figure 12 The images show the XRD patterns of the composite conductive coatings obtained in Examples 1, 6, and 7. Figure 12 It can be seen that at a current density of 5 A / dm², the main peaks are Cu (111), (200), and (220), with almost no Cu₂O characteristic peaks, indicating that pure Cu phase is mainly formed at low current. At a current density of 8 A / dm², Cu peaks dominate, but weak Cu₂O (111) and (200) characteristic peaks appear at approximately 36° and 42°, indicating a small amount of oxidation. When the current density is 10 A / dm², the Cu₂O peak is significantly enhanced, while the Cu peak still exists, forming a distinct Cu / Cu₂O mixed phase. Therefore, the current density directly affects the deposition rate and interfacial reaction kinetics. At low current, Cu… 2+ Slow reduction tends to form a pure Cu phase; increased current accelerates the deposition rate, but may lead to local pH changes and co-deposition / oxidation of oxygen, promoting Cu deposition. + It forms and crystallizes into Cu2O.

[0074] Figure 13 The graph shows the conductivity test results of the composite conductive coatings obtained in Examples 1, 6, and 7. The conductivity of the composite conductive coatings obtained in Examples 1, 6, and 7 was tested using 100 mL of electrolyte. Figure 13 As can be seen, the conductivity test showed that the current rose to 10 A / dm. 2 The coating conductivity reached its highest level (approximately 1.18 × 10⁻⁶). 7 S / m), but Figure 12 The XRD patterns clearly show that at 10 A / dm 2 The significantly enhanced diffraction peaks of the cuprous oxide (Cu₂O) impurity phase in the lower-deposited coating indicate decreased coating purity and increased oxidation. In contrast, the coating deposited at 8 A / dm² exhibits the strongest and sharpest diffraction peaks for metallic copper (Cu), with the weakest Cu₂O impurity peaks, demonstrating higher phase purity, a more complete crystal structure, and lower defect density. Considering coating purity, crystal quality, and performance stability, 8 A / dm² is the optimal process parameter.

[0075] Example 8:

[0076] The preparation process in this embodiment is the same as in Example 1, except that the deposition time in the second part is 10 min.

[0077] Example 9:

[0078] The preparation process in this embodiment is the same as in Example 1, except that the deposition time in the second part is 30 min.

[0079] Figure 14 XRD patterns of the composite conductive coatings prepared in Examples 1, 8, and 9. Figure 14 As can be seen, at a deposition time of 10 minutes, the Cu peak intensity is weak and the full width at half maximum (FWHM) is wide, indicating that the Cu grain size is small and the crystallization is incomplete. At this time, the rGO characteristic peak is relatively obvious. At a deposition time of 20 minutes, the Cu peak intensity is significantly enhanced and the FWHM narrows, indicating that the grains have grown and the crystallinity has increased. The rGO peak weakens and is covered by the Cu layer. At a deposition time of 30 minutes, the Cu peak is the strongest and sharpest, and the crystallinity is the highest, but the grains may coarsen due to excessive growth. The extended deposition time provides more sufficient reduction time for Cu ions and crystal growth time. The initial stage (10 minutes) is mainly the nucleation stage, with small crystal size; the middle stage (20 minutes) is the optimal growth period, with uniform crystal size; the later stage (30 minutes) may see abnormal grain growth, affecting the interfacial bonding force. In terms of deposition time, less rGO was deposited at 10 min, and a dense rGO / Cu conductive network could not be formed. At 30 min, the copper nanoparticles were excessively accumulated on the substrate, resulting in weak upper layer adhesion and easy detachment. At 20 min, the adhesion was strong and a dense rGO-intercalated copper nanoparticle network could be observed on the surface.

[0080] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0081] The parts of this invention not described in detail are well-known in the art. The above embodiments are provided merely for the purpose of describing the invention and are not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principles of the invention should be covered within the scope of the invention.

Claims

1. A reduced graphene oxide-copper composite conductive coating, characterized in that, In the reduced graphene oxide-copper composite conductive coating, the deposited reduced graphene oxide forms a continuous three-dimensional network structure with macro-pores on the substrate through the folding, stacking and overlapping of the layers; and the metal copper exists in the form of discrete nano-copper grains; the nano-copper grains are in close contact with the reduced graphene oxide without obvious gap; and the nano-copper grains are partially wrapped or anchored in the network by the reduced graphene oxide layers.

2. The reduced graphene oxide-copper composite conductive coating of claim 1, wherein, In the reduced graphene oxide-copper composite conductive coating, the reduced graphene oxide is uniformly distributed in multiple orientations, and some of the layers of the reduced graphene oxide are in the form of upright or inclined; and the nano-copper grains in the reduced graphene oxide-copper composite conductive coating form fine equiaxed crystal structures; Or, in the reduced graphene oxide-copper composite conductive coating, the layers of the reduced graphene oxide are mainly embedded in the substrate in the form of flat and folded, and the layers of the reduced graphene oxide and the substrate form an alternating layered configuration, and a composite structure with more nano-pores is formed at the interface between the reduced graphene oxide and the substrate; Or, the reduced graphene oxide mainly forms a local enrichment area in the form of agglomerates, and the reduced graphene oxide-copper composite conductive coating has a non-uniform structure in which the reduced graphene oxide agglomerates coexist with the copper grains.

3. The reduced graphene oxide-copper composite conductive coating according to claim 1 or 2, wherein, The size of the nano-copper grains is 10-100 nm.

4. The process for the production of the reduced graphene oxide-copper composite conductive coating according to any one of claims 1 to 3, characterized in that, The reduced graphene oxide-copper composite conductive coating is prepared by controlling the C / O ratio of the reduced graphene oxide, and the preparation process comprises the following steps: An electrolyte containing copper ions and reduced graphene oxide is prepared; The substrate is placed as a cathode in the electrolyte, and an external electric field is applied; After a certain reaction time, a reduced graphene oxide-copper composite conductive coating is formed on the cathode; The C / O ratio of the reduced graphene oxide is 2.9-13.

5. The process for the preparation of reduced graphene oxide-copper composite conductive coating as claimed in claim 4 wherein, The C / O ratio of the reduced graphene oxide is 5-13.

6. The process for the preparation of reduced graphene oxide-copper composite conductive coating as claimed in claim 4 wherein, The reduced graphene oxide is prepared at a reduction temperature of not less than 200℃.

7. The process for the preparation of reduced graphene oxide-copper composite conductive coating as claimed in claim 6 wherein, The reduced graphene oxide is prepared at a reduction temperature of 300-700℃.

8. The process for the preparation of reduced graphene oxide-copper composite conductive coating as claimed in claim 4 wherein, The current density of the applied electric field is not less than 5 A / dm 2 The reaction time is 10 minutes to 30 minutes.

9. The process for the preparation of reduced graphene oxide-copper composite conductive coating as claimed in claim 4 wherein, The electrolyte further contains polyacrylic acid, and the mass concentration of the polyacrylic acid is 0.1-0.5 mg / L.

10. The process for the preparation of reduced graphene oxide-copper composite conductive coating as claimed in claim 4 wherein, The pH of the electrolyte is 0.8-1.2.

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