Highly conductive oxygen-etched graphene copper composite material and preparation method thereof

Abstract

The invention discloses a high-conductivity oxygen-etched graphene copper composite material and a preparation method thereof, relating to the technical field of composite material preparation. The invention aims to solve the problem that the bonding between the copper layer and the graphene layer is poor, the interlayer spacing is large, the interlayer electron transmission effect is poor, and the further improvement of the conductivity of the graphene copper composite material is hindered. The invention specifically includes the following steps S1: preparing a graphene copper foil; S2: using a plasma etching technology to perform oxygen plasma etching on the graphene layers on both sides of the graphene copper foil; S3: stacking two or more layers of oxygen-etched graphene copper foil obtained in step S2 in a layered manner, and aligning the back surface of the upper oxygen-etched graphene copper foil with the front surface of the lower oxygen-etched graphene copper foil to obtain a multilayer oxygen-etched graphene copper foil material; S4: vacuum hot pressing the multilayer oxygen-etched graphene copper foil material to obtain an oxygen-etched graphene copper composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and in particular to a high-conductivity oxygen-etched graphene copper composite material and a preparation method thereof. Background Art

[0002] Copper is a metal with the second best conductivity after silver. It has stable chemical properties, has been widely studied, and its reserves and preparation costs are far lower than silver. It is currently the most consumed and widely used conductive material in society.

[0003] Copper is used in wire, cable, copper contact materials, and in various electrical appliances across a wide range of fields, including electrical and electronics, defense and military, power transmission and power generation, and aerospace. The electrical conductivity of copper determines key performance indicators such as engine motor losses, the weight of conductive cables, and the efficiency of electronic circuit boards. Further improving the electrical conductivity of copper is crucial for reducing transmission losses, reducing the weight of aerospace equipment, and improving mechanical performance. Traditional methods for increasing metal conductivity, including purification and single crystallization, have reached their upper limits in recent years. By reducing impurities in copper and single crystallizing it, the electrical conductivity of pure copper can be increased to 103% IACS, but this significantly increases costs. Adding other metals or non-metallic materials to copper to form composites offers the potential to further enhance copper conductivity.

[0004] Graphene is a two-dimensional material with a honeycomb carbon atomic structure, which was first successfully prepared in 20024. The special structure of graphene gives it an extremely high carrier mobility (15000cm 2 / (V·S)) and excellent mechanical properties (Young's modulus of 1100GPa and fracture strength of 130GPa). Therefore, graphene is regarded as an ideal composite material reinforcement, with the potential to further optimize copper conductivity and enhance mechanical properties.

[0005] Graphene copper composites combine the high mobility of graphene with the high conductive electron density of copper. Due to the mechanical strength of graphene itself, they have the advantages of high conductivity and high strength. Traditional methods for preparing graphene copper composites mainly include powder metallurgy and hot isostatic pressing. However, since graphene is already incomplete, a second phase is formed in copper, which hinders the transmission of electrons. The graphene copper composites prepared by powder metallurgy have a poor conductivity enhancement effect, and in most experiments, the conductivity is reduced. Among them, hot isostatic pressing can maintain the integrity of the graphene structure, retain the high mobility of graphene, and effectively combine copper and graphene together to obtain a layered graphene copper composite with very high conductivity. However, the graphene copper composite obtained by this method has poor bonding between copper and carbon atoms, a large interlayer spacing, and poor interlayer electron transmission, which hinders further improvement of the conductivity of the graphene copper composite. Summary of the Invention

[0006] The present invention provides a method for preparing a highly conductive oxygen-etched graphene copper composite material, which specifically includes the following steps:

[0007] S1: preparing a graphene copper foil, wherein the graphene copper foil comprises a copper base layer, and graphene layers are deposited on both sides of the copper base layer by chemical vapor deposition;

[0008] S2: using plasma etching technology, performing oxygen plasma etching on the graphene layers on both sides of the graphene copper foil to form oxygen-etched graphene copper foil;

[0009] S3: stacking two or more layers of oxygen-etched graphene copper foil obtained in step S2, with the back surface of the upper layer of oxygen-etched graphene copper foil aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, to obtain a multilayer oxygen-etched graphene copper foil material;

[0010] S4: vacuum hot pressing the multilayer oxygen-etched graphene copper foil material in step S3 to achieve bonding between two adjacent layers of graphene copper foil to obtain an oxygen-etched graphene copper composite material;

[0011] The oxygen plasma etching in step S2 uses an oxygen flow rate of 15 sccm, a plasma processing power of 20-60 W, and a processing time of 2-25 s;

[0012] In step S4, the hot pressing pressure is 100 MPa, the hot pressing temperature is 1000° C., and the hot pressing time is 30 min.

[0013] The present invention is further configured as follows: the copper base layer in step S1 has a thickness of 20-50 μm, and the graphene monolayer coverage deposited on the copper base layer is ≥50%.

[0014] The present invention is further configured such that: the oxygen plasma etching process in step S2 is performed in a vacuum environment.

[0015] The present invention is further configured as follows: in step S3, the number of stacked layers of oxygen-etched graphene copper foil is 10-200 layers.

[0016] The present invention is further configured as follows: the vacuum degree of hot pressing in step S4 is less than 5×10 -3 Pa.

[0017] The present invention is further configured as follows: during the process from step S2 to step S4, the graphene copper foil is stored or treated in a vacuum or inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing.

[0018] The present invention is further configured such that the graphene copper foil is stored or treated in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing.

[0019] The present invention also provides a high-conductivity oxygen-etched graphene copper composite material, which is prepared by the above preparation method.

[0020] The beneficial effects of the present invention are:

[0021] 1. By using oxygen plasma etching to treat the graphene layer of the graphene copper foil, impurities and dust left on the graphene surface during the chemical vapor deposition and transfer process can be removed, thereby cleaning the surface of the material and further avoiding the introduction of other impurity atoms. The presence of the graphene layer can protect the underlying copper base layer and prevent the copper base layer from being oxidized.

[0022] 2. Oxygen atoms are introduced near the interface between the graphene layer and the copper substrate, where they can form copper-oxygen and carbon-oxygen groups with copper and carbon. Through covalent bridging, the oxygen atoms close the distance between the copper substrate and the graphene layer, shifting from a low-strength van der Waals interaction to a covalent interaction, significantly improving the bonding strength. This enhanced copper-carbon bonding lowers the barrier for electron migration between the copper substrate and the graphene layer, further enhancing the conductivity of the graphene-copper composite, and further improving the conductivity of the oxygen-etched graphene-copper composite. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of Raman characterization of the results before and after etching of Example 2 is shown.

[0024] Figure 2 A schematic diagram of Raman characterization of the results before and after etching of Example 3 is shown.

[0025] Figure 3 A schematic diagram of Raman characterization of the results before and after etching of Example 4 is shown.

[0026] Figure 4 Shown is a schematic diagram of SEM characterization of the results before and after etching. DETAILED DESCRIPTION

[0027] Those skilled in the art can refer to the content of this article and appropriately improve the process parameters. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments. Relevant persons can modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0028] Example 1

[0029] The present invention provides a method for preparing a highly conductive oxygen-etched graphene copper composite material, which specifically includes the following steps:

[0030] S1: preparing a graphene copper foil, wherein the graphene copper foil comprises a copper base layer, and graphene layers are deposited on both sides of the copper base layer by chemical vapor deposition;

[0031] S2: using plasma etching technology, performing oxygen plasma etching on the graphene layers on both sides of the graphene copper foil to form oxygen-etched graphene copper foil;

[0032] S3: stacking two or more layers of oxygen-etched graphene copper foil obtained in step S2, and aligning the back surface of the upper layer of oxygen-etched graphene copper foil with the front surface of the lower layer of oxygen-etched graphene copper foil, that is, the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multilayer oxygen-etched graphene copper foil material;

[0033] S4: vacuum hot pressing the multi-layer oxygen-etched graphene copper foil material in step S3 to achieve bonding between two adjacent layers of graphene copper foil to obtain an oxygen-etched graphene copper composite material.

[0034] The thickness of the copper base layer in step S1 is 20-50 μm, and the coverage of the graphene monolayer deposited on the copper base layer is ≥50%.

[0035] The oxygen flow rate used in the oxygen plasma etching in step S2 is 15 sccm, the plasma processing power is 20-60 W, and the processing time is 2-25 s.

[0036] The oxygen plasma etching process in step S2 is performed in a vacuum environment.

[0037] The number of stacked layers of oxygen-etched graphene copper foil in step S3 is 10-200 layers.

[0038] In step S4, the hot pressing pressure is 100 MPa, the hot pressing temperature is 1000° C., and the hot pressing time is 30 min.

[0039] The vacuum degree of hot pressing in step S4 is less than 5×10 -3 Pa.

[0040] In the process of step S2 to step S4, the graphene copper foil is stored or processed in a vacuum or inert atmosphere throughout the entire process from the completion of oxygen plasma treatment to the end of vacuum hot pressing. In this application, an inert atmosphere is selected for storage or processing.

[0041] Example 2

[0042] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0043] S1: Prepare a copper foil with a thickness of 25 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 90%, to prepare a graphene copper foil.

[0044] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 50 W. Each side was treated for 10 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 1 As shown, the G peak and G' peak weaken to produce the D peak representing the defect. The structure before and after oxygen etching was characterized by scanning electron microscopy (SEM). The results are shown in Figure 2. Figure 4 shown.

[0045] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 16 layers of the oxygen-etched graphene copper foil obtained in step S2 with their front faces facing each other, that is, the back surface of the upper layer of oxygen-etched graphene copper foil is aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, so that the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0046] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0047] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0048] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 2.005 cm × 2.021 cm and were 0.374 mm thick. The electrical conductivity, measured using the van der Pauw method, was 120.2% IACS.

[0049] Example 3

[0050] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0051] S1: Prepare a copper foil with a thickness of 25 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 80%, to prepare a graphene copper foil.

[0052] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 50 W. Each side was treated for 15 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 2 shown.

[0053] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 32 layers of the oxygen-etched graphene copper foil obtained in step S2 with the front sides facing each other, that is, the back side of the upper layer of oxygen-etched graphene copper foil is aligned with the front side of the lower layer of oxygen-etched graphene copper foil, so that the back side of the upper layer is in contact with the front side of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0054] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0055] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0056] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 2.020 cm × 2.008 cm and were 0.717 mm thick. The electrical conductivity was measured using the van der Pauw method and was 119.4% IACS.

[0057] Example 4

[0058] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0059] S1: Prepare a copper foil with a thickness of 50 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 95%, to prepare a graphene copper foil.

[0060] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 30W. Each side was treated for 10 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 3 shown.

[0061] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 16 layers of the oxygen-etched graphene copper foil obtained in step S2 with their front faces facing each other, that is, the back surface of the upper layer of oxygen-etched graphene copper foil is aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, so that the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0062] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0063] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0064] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 1.984 cm × 2.017 cm and were 0.742 mm thick. The electrical conductivity, measured using the van der Pauw method, was 118.0% IACS.

[0065] Example 5

[0066] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0067] S1: Prepare a copper foil with a thickness of 20 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 90%, to prepare a graphene copper foil.

[0068] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 50 W. Each side was treated for 10 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 3 shown.

[0069] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 16 layers of the oxygen-etched graphene copper foil obtained in step S2 with their front faces facing each other, that is, the back surface of the upper layer of oxygen-etched graphene copper foil is aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, so that the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0070] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0071] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0072] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 1.994 cm × 2.007 cm and were 0.742 mm thick. The electrical conductivity, measured using the van der Pauw method, was 119.6% IACS.

[0073] Example 6

[0074] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0075] S1: Prepare a copper foil with a thickness of 25 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 90%, to prepare a graphene copper foil.

[0076] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 45 W. Each side was treated for 10 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 3 shown.

[0077] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 16 layers of the oxygen-etched graphene copper foil obtained in step S2 with their front faces facing each other, that is, the back surface of the upper layer of oxygen-etched graphene copper foil is aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, so that the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0078] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0079] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0080] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 2.011 cm × 2.027 cm and were 0.742 mm thick. The electrical conductivity, measured using the van der Pauw method, was 119.1% IACS.

[0081] Example 7

[0082] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0083] S1: Prepare a copper foil with a thickness of 25 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 90%, to prepare a graphene copper foil.

[0084] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 50W. Each side was treated for 2 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 3 shown.

[0085] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 16 layers of the oxygen-etched graphene copper foil obtained in step S2 with their front faces facing each other, that is, the back surface of the upper layer of oxygen-etched graphene copper foil is aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, so that the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0086] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0087] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0088] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 2.001 cm × 2.012 cm and were 0.742 mm thick. The electrical conductivity was measured using the van der Pauw method and was 116.8% IACS.

[0089] Example 8

[0090] This embodiment adopts the preparation method of Example 1 to prepare the graphene copper composite material, which specifically includes the following steps:

[0091] S1: Prepare a copper foil with a thickness of 25 μm, and deposit a graphene layer on both sides of the copper foil by chemical vapor deposition, with a single layer coverage of 90%, to prepare a graphene copper foil.

[0092] S2: In a reactive ion etching (RIE) machine, the graphene layer on both sides of the graphene copper foil was treated with oxygen ions at an oxygen flow rate of 15 sccm and a power of 50 W. Each side was treated for 25 seconds to form oxygen-etched graphene copper foil. The results before and after oxygen etching were characterized by Raman spectroscopy. Figure 3 shown.

[0093] S3: Cut the oxygen-etched graphene copper foil obtained in step S2 into standard squares of approximately 2 cm × 2 cm in size, and stack 16 layers of the oxygen-etched graphene copper foil obtained in step S2 with their front faces facing each other, that is, the back surface of the upper layer of oxygen-etched graphene copper foil is aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, so that the back surface of the upper layer is in contact with the front surface of the lower layer, to obtain a multi-layer stacked oxygen-etched graphene copper foil material.

[0094] S4: The front surface of the top layer and the back surface of the bottom layer of the oxygen-etched graphene copper foil material stacked in step S3 are evenly covered with graphite lubricant, and then placed in a vacuum hot pressing furnace. Hot pressing is carried out at a temperature of 1000°C and a uniform pressure of 100 MPa for 30 minutes. After the hot pressing is completed, the pressure is maintained and the temperature is naturally cooled for 40 minutes. The graphene copper composite material is then removed to obtain the resultant product.

[0095] It should be noted that the graphene copper foil is stored or processed in an inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing, except for inside and outside the vacuum hot pressing furnace.

[0096] The resulting graphene-copper composite was polished to remove any residual graphene and then cut into 2 cm × 2 cm squares. The squares measured 2.110 cm × 2.112 cm and were 0.742 mm thick. The electrical conductivity was measured using the van der Pauw method and was 114.3% IACS.

[0097] Example 9

[0098] This embodiment discloses a highly conductive oxygen-etched graphene copper composite material, which is prepared using the above-mentioned preparation method.

[0099] In summary, the present invention uses oxygen plasma etching to process the graphene layer of the graphene copper foil, which can remove impurities and dust left on the graphene surface during the chemical vapor deposition and transfer process, thereby achieving the effect of cleaning the surface of the material and further avoiding the introduction of other impurity atoms. The presence of the graphene layer can protect the underlying copper base layer and prevent the copper base layer from being oxidized.

[0100] Oxygen atoms are introduced near the interface between the graphene layer and the copper substrate, where they can form copper-oxygen and carbon-oxygen groups with copper and carbon. Through covalent bridging, the oxygen atoms bring the copper substrate and graphene layer closer together, shifting from a low-strength van der Waals interaction to a covalent interaction, significantly increasing the bonding strength. This enhanced copper-carbon bonding lowers the barrier for electron migration between the copper substrate and the graphene layer, further enhancing the conductivity of the graphene-copper composite, and further improving the conductivity of the oxygen-etched graphene-copper composite.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be within the scope of protection of the present invention.

Claims

1. A method for preparing a highly conductive oxygen-etched graphene copper composite material, characterized in that: The specific steps include: S1: preparing a graphene copper foil, wherein the graphene copper foil comprises a copper base layer, and graphene layers are deposited on both sides of the copper base layer by chemical vapor deposition; S2: using plasma etching technology, performing oxygen plasma etching on the graphene layers on both sides of the graphene copper foil to form oxygen-etched graphene copper foil; S3: stacking two or more layers of oxygen-etched graphene copper foil obtained in step S2, with the back surface of the upper layer of oxygen-etched graphene copper foil aligned with the front surface of the lower layer of oxygen-etched graphene copper foil, to obtain a multilayer oxygen-etched graphene copper foil material; S4: vacuum hot pressing the multilayer oxygen-etched graphene copper foil material in step S3 to achieve bonding between two adjacent layers of graphene copper foil to obtain an oxygen-etched graphene copper composite material; The oxygen plasma etching in step S2 uses an oxygen flow rate of 15 sccm, a plasma processing power of 20-60 W, and a processing time of 2-25 s; In step S4, the hot pressing pressure is 100 MPa, the hot pressing temperature is 1000° C., and the hot pressing time is 30 min.

2. The method for preparing the highly conductive oxygen-etched graphene copper composite material according to claim 1, wherein: The copper base layer in step S1 has a thickness of 20-50 μm, and the coverage of the graphene monolayer deposited on the copper base layer is ≥50%.

3. The method for preparing the highly conductive oxygen-etched graphene copper composite material according to claim 1, wherein: The oxygen plasma etching process in step S2 is performed in a vacuum environment.

4. The method for preparing the highly conductive oxygen-etched graphene copper composite material according to claim 1, wherein: In step S3, the number of stacked layers of oxygen-etched graphene copper foil is 10-200 layers.

5. The method for preparing the highly conductive oxygen-etched graphene copper composite material according to claim 1, wherein: The vacuum degree of hot pressing in step S4 is less than 5×10 -3 Pa.

6. The method for preparing the high-conductivity oxygen-etched graphene copper composite material according to claim 1, wherein: During the process from step S2 to step S4, the graphene copper foil is stored or treated in a vacuum or inert atmosphere from the completion of the oxygen plasma treatment to the end of the vacuum hot pressing.

7. The method for preparing the highly conductive oxygen-etched graphene copper composite material according to claim 6, wherein: The graphene copper foil is stored or processed in an inert atmosphere from the completion of oxygen plasma treatment to the end of vacuum hot pressing.

8. A highly conductive oxygen-etched graphene copper composite material, characterized in that: The method is as described in any one of claims 1 to 7.

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