Nickel-graphene composite material and preparation method thereof
By preparing nickel-graphene composite materials with 1-3 layers of graphene film on the surface of nickel metal, the problem of insufficient conductivity of nickel metal is solved, and the high conductivity and mechanical properties are improved, making it suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-31
AI Technical Summary
Precisely preparing 1-3 layers of graphene film on nickel metal surfaces to enhance their conductivity is challenging, as existing methods are difficult to achieve efficiently and are costly.
Graphene films were prepared on the surface of nickel foil using either flame etching or solid-state conversion methods. The coverage and number of graphene layers were then controlled through oxygen plasma etching and hot-press bonding processes to form a nickel-graphene composite material.
It significantly improves the electrical conductivity of nickel metal, increasing it by 1 to 4 times, enhances the mechanical and thermal management properties of materials, and reduces production costs, making it suitable for large-scale commercial production.
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Figure CN121756669A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metal material processing technology, and more specifically, to a method for preparing nickel-graphene composite materials to enhance the electrical conductivity of nickel metal. Background Technology
[0002] Nickel metal is widely used in electronic circuits, energy batteries, aerospace, and other fields due to its excellent resistance to chemical corrosion, thermal stability, and good electrical conductivity. For example, in equipment handling concentrated alkalis (such as sodium hydroxide), nickel metal is often used to manufacture components such as reaction vessels, evaporators, heat exchangers, pipes, and valves. Pure nickel is also widely used in environments that are not extremely high-temperature but require corrosion resistance and strength. In addition, pure nickel heat exchangers exhibit superior performance in applications handling high-purity water or corrosive media.
[0003] Although nickel exhibits better overall performance than copper in certain applications, its electrical conductivity is significantly lower than that of copper. Typically, copper has a conductivity of approximately 6.0 × 10⁻⁶. 7 S / m, while the conductivity of nickel is only about 1.4 × 10⁻⁶. 7 The S / m ratio means that copper's conductivity is approximately four times that of nickel. This difference results in more than four times the unwanted Joule heat loss when using nickel as a conductor compared to using copper. To address this issue, several methods exist to reduce the resistivity (or enhance the conductivity) of metallic nickel. For example, its resistance can be directly reduced by operating nickel at a lower temperature; or a copper-nickel alloy can be used, leveraging copper's high conductivity to enhance the overall conductivity of the system. Similarly, surface plating with gold or silver can be employed, based on a similar mechanism to enhance the system's conductivity. However, the application of these solutions is limited due to copper's poor corrosion resistance and the high cost of gold and silver.
[0004] Among all highly conductive materials, graphene has the highest conductivity, approximately 1.0 × 10⁻⁶. 8 S / m. Therefore, graphene has also been used to enhance the electrical conductivity of metals such as copper and nickel. In previous research, Zhang Di's team at Shanghai Jiao Tong University obtained copper-graphene composite materials with better electrical conductivity than pure copper by growing 1-3 layers of graphene on the surface of copper foil and using a layer-by-layer stacking hot-pressing sintering method. Their research showed that as the number of graphene layers increases, its conductivity gradually deteriorates. For example, the electrical conductivity of bulk graphite is only about 0.5 × 10⁻⁶ S / m. 5 S / m. Therefore, only by using 1-3 layers of graphene can the conductivity be significantly enhanced.
[0005] Unlike copper, precisely fabricating 1-3 layer graphene films on nickel surfaces presents a greater challenge. This is primarily because carbon sources dissolve more readily in nickel, making it easier to grow thicker graphene films on the nickel surface, typically far exceeding ten layers. For example, Professor Kaihui Liu's research group at Peking University has used a solid carbon source method to directly grow graphene films with thicknesses exceeding tens of micrometers on nickel foil.
[0006] Therefore, how to accurately prepare 1-3 layer graphene films on the surface of metallic nickel and apply them to obtain nickel conductors with higher conductivity has become a challenging issue. Summary of the Invention
[0007] The purpose of this invention is to address the above-mentioned problems by proposing a nickel-graphene composite material and its preparation method. The aim is to prepare a nickel-graphene composite material with excellent electrical conductivity by precisely preparing 1 to 3 layers of graphene film on the surface of nickel metal and combining it with a hot pressing process.
[0008] The technical solution of this invention is: In a first aspect, the present invention provides a nickel-graphene composite material comprising multiple nickel foil strips, with a graphene layer between adjacent nickel foil strips, the graphene layer having a thickness of 2-4 layers, and a graphene layer provided or not provided on the outer surface of the outermost nickel foil strip, wherein the graphene layer on the outer surface of the outermost nickel foil strip has 1-2 layers.
[0009] Furthermore, the graphene layer on the single-layer nickel foil strip has a coverage of 40% to 90%.
[0010] Secondly, the present invention provides a method for preparing a nickel-graphene composite material, comprising the following steps: S1. Nickel foil pretreatment: Select nickel foil strips with a thickness of 5 to 15 micrometers, and flatten and clean them. S2. Graphene preparation: Graphene films are prepared on the surface of pretreated nickel foil using either the flame method or the solid-state conversion method. S3. Etching and thinning: The graphene film is subjected to oxygen plasma surface treatment to remove excess graphene film and obtain graphene nickel foil strip with a graphene layer of preset thickness on the surface. S4. Hot pressing bonding: The graphene nickel foil strips that have been etched and thinned are stacked and then hot-pressed together.
[0011] Furthermore, in S1, the nickel foil pretreatment involves continuously conveying the nickel foil strip through an unwinding mechanism and sequentially passing it through a mechanical flattening unit and a cleaning unit for pretreatment.
[0012] Furthermore, the flame method described in S2 employs a distributed multi-nozzle flame array system. The flame nozzles are linearly arranged along the travel direction of the nickel foil strip, symmetrically positioned vertically. A mixture of methane and hydrogen is input, with a methane volume fraction of 5–15%, a total flow rate of 10–50 L / min, a flame temperature of 1100–1300℃, a nickel foil strip passing speed of 0.5–2.0 m / min, and an exposure time of 2–8 seconds.
[0013] Furthermore, the solid-state conversion method described in S2 includes magnetron sputtering or chemical vapor deposition; wherein, The magnetron sputtering method includes first depositing a solid carbon film with a thickness of 0.7–2.1 nm on the surface of a nickel foil strip by magnetron sputtering, and then... -3 Under Pa conditions, annealing was carried out using a non-contact heater with a heating rate of 100–500 ℃ / s, a peak temperature of 900–1100 ℃, and a holding time of 5–30 seconds. The chemical vapor deposition method includes placing a nickel foil strip in a chemical vapor deposition chamber, under a vacuum degree better than 1×10⁻⁶. -3 Under Pa conditions, methane gas with a flow rate of 90-110 sccm is introduced and deposited at 500-800 °C for 5-20 minutes; then, under the same vacuum conditions, a non-contact heater is used to raise the temperature to 900-1100 °C at a rate of 100-500 °C / s and hold for 5-30 seconds to complete the solid-phase transformation.
[0014] Furthermore, the oxygen plasma surface treatment in S3 employs an oxygen plasma treatment device, including a cavity, an oxygen plasma source, and a gas supply system. The gas flow rate is 20 to 500 sccm, the pressure inside the cavity is 0.5 to 2 atm, and the treatment time is 50 to 1000 seconds. The oxygen plasma source is a radio frequency power supply or a microwave power supply, and the oxygen purity in the gas supply system is not less than 99.99%.
[0015] Furthermore, after S2, the nickel foil with graphene film prepared is sampled and characterized to detect the coverage A, average thickness B, and thickness uniformity C of the graphene film layer; the detection area is greater than 1 square centimeter, and the detection point density is greater than 1 / square millimeter; when A is less than 40% or greater than 90%, B is greater than 10 layers, and the absolute value of C is greater than 5, it is judged as unqualified.
[0016] Furthermore, after S3, the etched and thinned graphene nickel foil strip was sampled and characterized again to test the coverage A', average thickness B', and thickness uniformity C' of the graphene film; the test area was greater than 1 square centimeter, and the test point density was greater than 1 / square millimeter; when A' was less than 40% or greater than 90%, B' was 0 or greater than 4 layers, and the absolute value of C' was greater than 2, it was judged as unqualified.
[0017] Furthermore, the defective products undergo surface oxidation treatment before being transferred to S3.
[0018] The beneficial effects of this invention are: This invention significantly improves the conductivity of nickel metal by controlling the graphene coverage and number of layers. The graphene coverage is controlled between 40% and 90%, and the number of layers is controlled between 1 and 2. The effective application of graphene can be achieved without completely covering the surface of the nickel foil, reducing the requirements for graphene growth. At the same time, it can effectively enhance the conductivity of nickel metal, making large-scale commercialization possible.
[0019] 1. Significantly Improved Overall Electrical Performance: This invention effectively improves the electrical conductivity of materials by constructing a nickel-graphene composite structure. Depending on the thickness of the nickel foil and the graphene coverage, the conductivity can be increased by 1 to 2 times compared to pure nickel; under preferred conditions, the conductivity can be increased by up to 4 times, reaching a level comparable to metallic copper, providing a better material choice for high conductivity applications.
[0020] 2. Excellent mechanical reinforcement and thermal management properties: Graphene, as a reinforcing phase, effectively improves the modulus and strength of the composite material, with both increases exceeding 10%. Simultaneously, the thermal conductivity of this composite material is more than 50% higher than that of pure nickel, combining excellent mechanical properties with good heat dissipation potential.
[0021] 3. Enhanced corrosion resistance and stability: This invention uses nickel as the matrix, avoiding the problem of copper's easy corrosion in harsh environments. In addition, graphene itself has excellent chemical inertness and mechanical stability, and its coating can further protect the nickel matrix, thereby significantly improving the overall corrosion resistance and environmental stability of the composite material.
[0022] 4. Low-cost preparation process suitable for large-scale production: First, the graphene growth technologies used (such as flame method and solid-state conversion method) significantly reduce equipment investment and production costs compared to conventional methods. Second, this process has less stringent requirements on the coverage of graphene on nickel foil; performance improvement can be achieved without achieving complete coverage, reducing the stringent requirements for process precision and improving production yield. Finally, the entire preparation process is highly compatible with roll-to-roll industrial production lines, laying the foundation for large-scale, continuous commercial production and making the commercial application of this high-performance material possible.
[0023] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description
[0024] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.
[0025] Figure 1 A schematic diagram of the structure of the nickel-graphene composite material of the present invention is shown. Detailed Implementation
[0026] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.
[0027] This invention provides a nickel-graphene composite material, comprising multiple nickel foil strips, such as... Figure 1 As shown, N is 2 or more stacked sheets, and there is a graphene layer between adjacent nickel foil strips. The thickness of the graphene layer is 2-4 layers. There may or may not be a graphene layer on the outer surface of the outermost nickel foil strip. There are 1-2 graphene layers on the outer surface of the outermost nickel foil strip. The coverage of the graphene layer on a single nickel foil strip is 40% to 90%.
[0028] The 1-2 graphene layers in this invention refer to a single layer of graphene, which is a two-dimensional material consisting of only one layer of tightly packed carbon atoms with a thickness of approximately 0.335 nanometers, and a two-layer graphene structure consisting of two single-layer graphene layers with a thickness of approximately 0.67 nanometers.
[0029] Example 1
[0030] S1. Select a nickel foil strip with a thickness of 10 micrometers and a width of 20 millimeters, and flatten and clean the nickel foil. Flattening is performed using a mechanical method, with the distance between the pressure rollers being 1.3 times the thickness of the nickel foil, and the roller speed being 2 meters per minute. The cleaning solution includes deionized water, ethanol, and acetone, and the cleaning temperature is controlled at 30 degrees Celsius for 10 minutes. After cleaning, dry the foil with nitrogen gas.
[0031] S2. Graphene is prepared on the cleaned nickel foil surface using a flame method. The flame nozzle size is 5 mm, and there are 4 nozzles, positioned on both the top and bottom surfaces of the nickel foil. The nickel foil is continuously rolled through the flame treatment chamber, and the temperature inside the chamber is controlled at 1100 degrees Celsius.
[0032] S3. The prepared graphene sample was characterized using Raman spectroscopy, scanning electron microscopy, and focused ion beam analysis. The detection area was 2 square centimeters, and the detection point density was 2 per square millimeter.
[0033] S4. Surface treatment of non-conforming samples is performed using an oxidizing liquid immersion method. The main component of the oxidizing liquid is hydrogen peroxide, and the liquid concentration is 5%. The nickel foil is immersed in the oxidizing liquid for 5 minutes at a temperature of 30 degrees Celsius.
[0034] S5. Perform oxygen plasma surface treatment on the qualified graphene samples. The oxygen plasma treatment power is 200 watts, the treatment time is 5 minutes, and the gas flow rate in the cavity is 100 sccm.
[0035] S6. The etched graphene sample is sampled and characterized again, and the detection method is the same as in S3.
[0036] S7. The qualified graphene sample is hot-pressed and bonded in multiple layers. The hot-pressing temperature is 500 degrees Celsius, the pressure is 5 MPa, and the heat and pressure holding time is 5 minutes. The thickness of the graphene layer formed between adjacent nickel foil strips is 2-4 layers. The outer surface of the outermost nickel foil strip may or may not have a graphene layer. The graphene layer on the outer surface of the outermost nickel foil strip is 1-2 layers.
[0037] S8. The resistance of the finally obtained nickel-graphene composite material is measured.
[0038] Example 2
[0039] The difference from Example 1 is that S2 uses a solid-phase conversion method, with methane as the carbon source, and chemical vapor deposition is used for carbon source deposition. The reaction gas flow rate is 100 sccm, and the deposition time is 5 minutes. The other steps are the same as in Example 1.
[0040] Example 3
[0041] The difference from Example 2 is that the deposition time is 10 minutes. The other steps are the same as in Example 2.
[0042] Example 4
[0043] The difference from Example 2 is that the deposition time is 20 minutes. The other steps are the same as in Example 2.
[0044] Comparative Example 1 The difference from Example 1 is that, in S2, instead of using a flame method or a solid-phase conversion method, a graphene solution is directly coated onto the surface of a nickel foil. The other steps are the same as in Example 1.
[0045] Comparative Example 2 The difference from Example 1 is that, in S4, instead of using an oxidizing liquid immersion method, a mechanical polishing method is used to remove excess graphene. The other steps are the same as in Example 1.
[0046] The resistivity of the nickel-graphene composite materials obtained in the above examples and comparative examples was measured using the four-probe method, the graphene coverage and number of layers were observed using scanning electron microscopy, and the graphene quality was analyzed using Raman spectroscopy. The results are shown in the table below:
[0047] As shown in the table above, the nickel-graphene composite material obtained in this application has lower resistivity, higher graphene coverage, and better graphene quality compared to the comparative examples. In Comparative Example 1, direct coating of graphene solution could not achieve uniform coverage, resulting in higher resistivity; in Comparative Example 2, the mechanical polishing method was used to remove excess graphene, which easily damaged the graphene structure, leading to a decrease in coverage and quality.
[0048] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. A nickel-graphene composite material, characterized by, The graphene layer between the adjacent nickel foil strips is 2-4 layers thick, and the graphene layer on the outer surface of the outermost nickel foil strip is 1-2 layers thick.
2. The nickel-graphene composite of claim 1, wherein, The coverage of the graphene layer on the single-layer nickel foil strip is 40% to 90%.
3. A method of producing the nickel-graphene composite material according to any one of claims 1 to 2, characterized by The method comprises the following steps: S1, nickel foil pretreatment, selecting a nickel foil strip with a thickness of 5-15 microns, flattening and cleaning the nickel foil strip; S2, graphene preparation, preparing a graphene film on the surface of the pretreated nickel foil by a flame method or a solid-phase conversion method; S3, etching and thinning, performing oxygen plasma surface treatment on the graphene film to remove excess graphene film, and obtaining a graphene nickel foil strip with a graphene layer of a preset thickness on the surface; S4, hot-pressing and bonding, hot-pressing and bonding the graphene nickel foil strip after etching and thinning.
4. The method of claim 3, wherein In S1, the nickel foil pretreatment is to continuously transport the nickel foil strip through a unwinding mechanism, and sequentially pass through a mechanical flattening unit and a cleaning unit for pretreatment.
5. The method of claim 3, wherein In S2, The flame method uses a distributed multi-nozzle flame array system, the flame nozzles are linearly arranged along the advancing direction of the nickel foil strip, are symmetrically arranged up and down, input methane and hydrogen mixed gas, the volume fraction of methane is 5-15%, the total flow rate is 10-50 L / min, the flame temperature is 1100-1300℃, the passing speed of the nickel foil strip is 0.5-2.0 m / min, and the exposure time is 2-8 seconds.
6. The method of claim 3, wherein The solid-phase conversion method in S2 comprises a magnetron sputtering method or a chemical vapor deposition method; wherein, The magnetron sputtering method comprises, first depositing a solid carbon film with a thickness of 0.7-2.1 nm on the surface of the nickel foil strip by magnetron sputtering, then annealing by using a non-contact heater under a vacuum degree of better than 1×10⁻³ Pa, the heating rate is 100-500 ℃ / s, the peak temperature is 900-1100 ℃, and the holding time is 5-30 seconds; The chemical vapor deposition method comprises, placing the nickel foil strip in a chemical vapor deposition cavity, under a vacuum degree of better than 1×10⁻³ Pa, inputting methane gas with a flow rate of 90-110 sccm, depositing for 5-20 minutes at 500-800 ℃; then under the same vacuum condition, using a non-contact heater to heat up to 900-1100 ℃ at a rate of 100-500 ℃ / s, and holding for 5-30 seconds to complete the solid-phase conversion.
7. The method of claim 3, wherein In S3, the oxygen plasma surface treatment uses an oxygen plasma treatment device, which comprises a cavity, an oxygen plasma source and a gas supply system, the gas flow rate is 20 to 500 sccm, the cavity internal pressure is 0.5 to 2 atm, and the treatment time is 50 seconds to 1000 seconds; the oxygen plasma source is a radio frequency power supply or a microwave power supply, and the oxygen purity in the gas supply system is not less than 99.99%.
8. The method of claim 3, wherein After S2, the nickel foil with the graphene film is sampled and characterized to detect the coverage A, the average thickness B, and the thickness uniformity C of the graphene film layer; the detection area is greater than 1 square centimeter, and the detection point density is greater than 1 per square millimeter; when A is less than 40% or greater than 90%, B is greater than 10 layers, and the absolute value of C is greater than 5, it is determined as unqualified.
9. The method of claim 3, wherein After S3, the graphene nickel foil strip after etching and thinning is sampled and characterized again to detect the coverage A', the average thickness B', and the thickness uniformity C' of the graphene film layer; the detection area is greater than 1 square centimeter, and the detection point density is greater than 1 per square millimeter; when A' is less than 40% or greater than 90%, B' is 0 or greater than 4 layers, and the absolute value of C' is greater than 2, it is determined as unqualified.
10. The method according to claim 8 or 9, characterized in that, The unqualified products are subjected to surface oxidation treatment, and then transferred to S3.