Graphene heat-conducting film for repairing defects through nickel catalysis, preparation method and application

Abstract

The invention discloses a graphene heat conduction film for repairing defects through nickel catalysis, a preparation method and application, and belongs to the technical field of graphene materials. The preparation method comprises the following steps: removing part of oxygen-containing groups of a graphene oxide film through pretreatment to obtain a pretreated film; under a vacuumizing condition, introducing a nickel source into the pretreated membrane by a water-phase electrolytic nickel source through solvent permeation and infiltration to obtain a Ni / pretreated membrane; carrying out carbonization treatment on the Ni / pretreatment film to obtain a carbonized film; and carrying out graphitization treatment on the carbonized film to obtain the graphene heat-conducting film. Compared with a traditional preparation method, the graphene heat-conducting film provided by the invention has the advantages of fewer surface defects, higher crystallinity and higher heat-conducting property.

Description

Technical Field

[0001] The invention belongs to the technical field of graphene materials, and in particular relates to a nickel-catalyzed defect-repairing graphene thermal conductive film, a preparation method and an application thereof. Background Art

[0002] Traditional metals that rely on free electrons as heat conduction carriers have a thermal conductivity of only about 400W / (m˙K), while graphene has a theoretical thermal conductivity of 5300W / (m˙K), making it the material with the highest theoretical thermal conductivity among currently known materials. It is an ideal candidate for heat dissipation materials in the 5G era, so graphene-based thermal conductive materials have received widespread attention.

[0003] Graphene thermal conductive film has excellent thermal conductivity and is a new type of heat dissipation material currently used in 5G electronic devices. Phonons are the main heat carrier of graphene when it is close to room temperature. The excellent thermal conductivity of graphene thermal conductive film is mainly attributed to the long-range ordered carbon atoms SP in graphene thermal conductive film. 2 Hybrid aromatic structure, large amount of SP 2 Hybridized carbon atoms form a carbon hexagonal aromatic structure through covalent bonds, which has a thermal conductivity one order of magnitude higher than that of traditional metals. Although the theoretical thermal conductivity of graphene is very high, in the industrial mass production process, too many defects in the graphene sheet lead to serious scattering of phonons during transmission. Excessive phonon scattering is very unfavorable for the transmission of phonons, resulting in reduced thermal conductivity of graphene thermal conductive film. Therefore, the first step to improve the thermal conductivity of graphene thermal conductive film is to improve the integrity of the graphene structure.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to reduce the intrinsic defect degree of graphene thermal conductive film in industrial mass production, and to provide a graphene thermal conductive film with nickel catalytic defect repair, a preparation method and an application.

[0006] The first aspect of the present invention provides a method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, comprising:

[0007] Pretreatment: removing some oxygen-containing groups of the graphene oxide film by pretreatment to obtain a pretreated film;

[0008] Introducing a nickel source: Under vacuum conditions, introducing an aqueous electrolytic nickel source into the pretreatment film by solvent infiltration to obtain a Ni / pretreatment film;

[0009] Carbonization treatment: carbonizing the Ni / pre-treated film to obtain a carbonized film;

[0010] Graphitization treatment: graphitizing the carbonized film to obtain the graphene thermal conductive film.

[0011] In some embodiments, the films to be treated are stacked in the pretreatment and / or carbonization treatment and / or graphitization treatment steps, and graphite films are intercalated between the stacked individual films to be treated.

[0012] In some embodiments, the pretreatment step specifically includes:

[0013] The graphene oxide film is pretreated at low temperature under a load, wherein the temperature of the low temperature pretreatment is 200-400° C., the heating rate is 0.2-2° C. / min, and the temperature is kept for 1-4 hours;

[0014] The weight of the load is ≥ 20 kg.

[0015] In some embodiments, the step of introducing a nickel source specifically comprises:

[0016] The pretreated membrane is loaded and immersed in the aqueous electrolytic nickel source, and vacuumed for 1-4 hours, with the vacuum degree set in the range of -100 KPa to -90 KPa.

[0017] In some embodiments, the carbonization step specifically includes:

[0018] After the Ni / pre-treated film is loaded, the temperature is raised to 1000-1350° C. at a heating rate of 0.5-2° C. / min in an inert gas atmosphere, and kept at this temperature for 1-6 hours;

[0019] The Ni / pretreatment film load weight is ≥5kg.

[0020] In some embodiments, the graphitization step specifically includes:

[0021] After the carbonized film is loaded, in an inert gas atmosphere, the temperature is raised to the low temperature zone at a heating rate of 5°C / min, then raised to the medium temperature zone at a heating rate of 1-5°C / min, and kept warm for 1-3h; finally, the temperature is raised to the high temperature zone at a heating rate of 0.5-1°C, and kept warm for 0.5-3h.

[0022] In some embodiments, the temperature of the low temperature zone is 900-1100°C;

[0023] The temperature of the medium temperature zone is 2500-2700°C;

[0024] The temperature in the high temperature zone is 2800-3300°C.

[0025] The third aspect of the present invention provides a nickel-catalyzed defect-repairing graphene thermal conductive film, the thermal diffusion coefficient of which is 860 mm 2 / s or more, nickel-free, pure graphene thermal conductive film;

[0026] It is prepared by the above-mentioned preparation method.

[0027] A third aspect of the present invention provides a heat dissipation device, comprising a graphene thermally conductive film prepared by the above preparation method or the above graphene thermally conductive film.

[0028] A fourth aspect of the present invention provides an electronic device, comprising the graphene thermal conductive film prepared by the above preparation method or the above graphene thermal conductive film or the above heat dissipation device.

[0029] Compared with the prior art, the technical effects achieved by the present invention are as follows:

[0030] (1) The present invention provides a graphene thermal conductive film and a preparation method thereof, which has fewer defects, higher crystallinity, and higher thermal conductivity than graphene thermal conductive films prepared by traditional preparation methods, especially graphene thermal conductive films prepared in industrial mass production.

[0031] (2) The present invention provides a graphene thermal conductive film and a preparation method thereof. Compared with the graphene thermal conductive film prepared by the traditional preparation method, under the same thermal conductivity conditions, the graphitization temperature is lower.

[0032] (3) The present invention provides a graphene thermal conductive film and a preparation method thereof. Compared with the traditional preparation method, during the carbonization stage, the anchor nickel source absorbs the gaseous carbon source formed by the in-situ carbon etching accompanying the removal of oxygen-containing groups, providing a carbon source for the subsequent carbon atom rearrangement to repair defects.

[0033] (4) The present invention provides a graphene thermal conductive film and a preparation method thereof, which utilizes the carburization and carbon precipitation catalytic properties of the anchor nickel source during the graphitization stage to reduce SP 3 Conversion of hybrid carbon to SP 2 The energy level barrier of hybrid carbon repairs the defects. At the same time, the carbon precipitation accompanied by the volatilization of the anchor nickel source provides a carbon source for the rearrangement of carbon atoms to repair the defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the stacked structure of graphene oxide film of the present invention;

[0035] Figure 2 is the thermogravimetric curve of graphene oxide;

[0036] Figure 3 This is a graph of thermal diffusion coefficient of the graphene thermal conductive film obtained in Example 1;

[0037] Figure 4 This is a thermal SEM image of the graphene thermal conductive film obtained in Example 1;

[0038] Figure 5This is a thermal EDS image of the graphene thermal conductive film obtained in Example 1;

[0039] Figure 6 This is a graph of the thermal diffusion coefficient of the graphene thermal conductive film obtained in Comparative Example 1;

[0040] Figure 7 The thermal diffusion coefficient diagram of the graphene thermal conductive film obtained in Comparative Example 2;

[0041] Figure 8 This is a graph of thermal diffusion coefficient of the graphene thermal conductive film obtained in Comparative Example 3;

[0042] Fig. 9 This is a graph of the thermal diffusion coefficient of the graphene thermal conductive film obtained in Example 2. DETAILED DESCRIPTION

[0043] The content of the present invention is further described below in conjunction with specific examples, but it should not be construed as limiting the present invention. If not specifically indicated, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art, and there is no specific restriction on their sources, and they can be purchased in the market or prepared according to conventional methods well known to those skilled in the art.

[0044] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0045] The technical solution of the present invention is described below by specific embodiments. It should be understood that one or more steps mentioned in the present invention do not exclude the existence of other methods and steps before and after the combination step, or other methods and steps can be inserted between these explicitly mentioned steps. It should also be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Unless otherwise specified, the numbering of each method step is only for the purpose of identifying each method step, and does not limit the order of arrangement of each method or limit the scope of implementation of the present invention. The change or adjustment of the relative relationship thereof can also be regarded as the scope of implementation of the present invention without substantial changes in the technical content.

[0046] The invention provides a method for preparing a graphene thermal conductive film with defects repaired by nickel catalysis. The method comprises the following steps: low-temperature heat treatment of a graphene oxide film at 200-400 DEG C is performed to remove part of oxygen-containing groups to obtain an expanded pre-treated film; residual oxygen-containing groups in the pre-treated film are used to anchor aqueous electrolytic salt cations, and a high-concentration aqueous electrolytic nickel source is introduced into the graphene pre-treated film through solvent infiltration under vacuum conditions, and the Ni / pre-treated film is obtained after drying the water; and the catalytic characteristics of carburization and carbon precipitation of the nickel source are used in the carbonization and graphitization stages to repair graphene sheet defects and improve graphene crystallinity, thereby obtaining a graphene thermal conductive film with a high thermal diffusion coefficient.

[0047] The method for preparing the nickel-catalyzed defect-repairing graphene thermal conductive film provided by the present invention uses conventional graphene oxide dry film purchased from Yuntian Mo Rui as raw material, and comprises:

[0048] S1, the graphene oxide film 1 is cut and stacked, and a graphite film is inserted between the stacked single graphene oxide films. In some embodiments, Figure 1 As shown, the stacking method is that a graphene oxide film 1 and a graphite film 2 are stacked back and forth, and then a weight with a load mass ≥ 20 kg is loaded as a weight, and the loaded graphene oxide film is transferred to a blast oven, and the temperature is increased to a pretreatment temperature of 200-400°C at a heating rate of 0.2-2°C / min, and the temperature is kept for 1-4h, and the pretreatment film is obtained after the temperature is naturally cooled to room temperature.

[0049] The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness and the formation of a large number of microporous structures in the cross section. According to the thermogravimetric curve of graphene oxide (such as Figure 2 As shown in the figure, 200-400°C can remove groups such as hydroxyl and epoxy groups in graphene oxide, while groups such as carboxyl groups can only be completely removed at around the carbonization temperature.

[0050] The increase in temperature will cause the organic components in the graphene oxide to undergo pyrolysis and polycondensation reactions, resulting in the rearrangement of carbon atoms and the formation of a more stable carbon structure. At the same time, the oxygen-containing functional groups on the surface of the graphene oxide film may also undergo esterification, dehydration and other reactions, thereby enhancing the bonding force between the two graphene oxide films; even in the absence of a chemical reaction, the two graphene oxide films may be bonded to each other through physical adsorption and van der Waals forces. For the above reasons, during the pretreatment process, adjacent graphene films will bond, and the intercalation of graphite films can reduce the occurrence of this bonding phenomenon, improve the subsequent film removal efficiency, and avoid damage to the film material during the separation process (the reasons for intercalation in the subsequent carbonization and graphitization stages are the same as above).

[0051] S2. Use deionized water to prepare a water-soluble nickel salt into a solution with a solid content of 1-10%, immerse the pretreatment membrane obtained in step S1 in the nickel salt aqueous solution, and use a weight to press on the pretreatment membrane. Transfer the nickel salt solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to the range of -100KPa to -90KPa, and continue to evacuate for 1-4h to allow the nickel salt aqueous solution to infiltrate the pretreatment membrane through infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 100-200°C for 10-24h to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0052] In some embodiments, the nickel salt can be any inorganic or organic nickel salt soluble in water, such as nickel acetate tetrahydrate, nickel nitrate, etc. More preferably, the nickel salt is an organic nickel salt soluble in water, such as nickel acetate tetrahydrate.

[0053] S3. After stacking the Ni / pretreated films obtained in step S2, insert a graphite film between the single Ni / pretreated films and transfer them to a carbonization furnace with a load of ≥5kg. In an inert gas atmosphere, increase the temperature to 1000-1350°C at a heating rate of 0.5-2°C / min, keep warm for 1-6h, and naturally cool to room temperature to complete the carbonization treatment to obtain a carbonized film.

[0054] In this step, all oxygen-containing groups are basically removed from the Ni / pretreatment film. The gaseous carbon source formed by the in-situ carbon etching and the carbon source cracked by nickel acetate at the oxygen-containing group removal point are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation.

[0055] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between the single carbonized films to the graphitization furnace, use graphite plates for natural load, and raise the temperature to 1000°C at a heating rate of 5°C / min; then raise the temperature to 2500-2700°C in the medium temperature zone at a heating rate of 1-5°C / min, and keep it warm for 1-3h; finally, raise the temperature to 2800-3300°C in the high temperature zone at a heating rate of 0.5-1°C, and keep it warm for 0.5-3h. The entire graphitization process of this step uses an inert gas, preferably high-purity argon. Atmosphere protection is performed. At the medium temperature zone, the anchor nickel source is extremely active and fluid. At the medium temperature zone, the anchor nickel source that has undergone a round of carburization and carbon precipitation absorbs oxygen-containing groups to fall off and form SP 3 Hybridized carbon source; when the graphene film enters the high-temperature graphitization temperature zone, the anchor nickel source uses its catalytic effect of carburization and carbon precipitation to promote the rearrangement of carbon atoms. At the same time, the nickel source volatilizes and precipitates carbon to provide a carbon source for the rearrangement of carbon atoms to repair defects. After the insulation is completed, it is cooled to room temperature to obtain a graphitized film, that is, a graphene thermal conductive film.

[0056] In some embodiments, the inert gas may be any inert gas such as nitrogen or argon, but the corresponding inert gas is selected based on the structure of the carbonization / graphitization furnace. For example, the furnace used by the applicant in the production process is ventilated from the top, and the density of argon is lower than that of air. Argon is always above the air, and the introduction of argon can push out the air, ensuring that the air is discharged more cleanly.

[0057] S5. Testing the carbonized film obtained in step S4.

[0058] In some embodiments, the weight loaded in step S1 has no special material requirements and only needs to withstand the pretreatment temperature, such as iron blocks, graphite plates, etc. Since pretreatment, carbonization, and graphitization will remove functional groups and release a large amount of gas, causing the membrane material to expand in volume, in the absence of weight, it will expand several times in the height direction of the membrane material, and the expansion coefficient is uncontrollable, resulting in poor product uniformity. The pretreatment stage produces the most gas, and a too light load will produce gas that causes the membrane to expand too much, and the gas release process will cause tearing damage to the membrane.

[0059] In step S2, the load can be a heavy object that does not react with nickel salt, such as a graphite plate. There is no specific requirement for the load, and the membrane material only needs to be pressed down and immersed in the nickel salt. The gas production is reduced during the carbonization stage, and the load is preferably a high-temperature resistant graphite material. If the load is too light, gas will be produced, causing the membrane to expand too much, and the gas release process will cause tearing damage to the membrane.

[0060] In the graphitization stage of step S4, almost no gas is produced, but a small amount of functional groups may still break and produce gas. The load only needs to ensure that it does not expand too much, and no specific limit is imposed on the load. Graphite plates are used for load-bearing in the graphitization stage. Graphite plates are resistant to high temperatures and are inert. Metal plates cannot be used because they will melt above 2000°C.

[0061] Example 1

[0062] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0063] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and a graphite film is intercalated between a single graphene oxide film and the substrate. Then, a square iron with a load of 30 kg is loaded as a weight. The loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 260°C at a heating rate of 1°C / min. The temperature is kept for 2 hours, and the pretreatment film is obtained after the temperature is naturally cooled to room temperature. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0064] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 8%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use an 8kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -98KPa, and continue to evacuate for 3h, so that the nickel acetate aqueous solution is infiltrated into the pretreatment membrane by infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 150°C for 24h to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0065] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between the single Ni / pretreatment film and transfer the graphite plate with a load of 10kg to the carbonization furnace. Raise the temperature to 1300℃ at a heating rate of 1.5℃ / min in a nitrogen atmosphere and keep it warm for 2h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by the in-situ carbon etching and the carbon source cracked by nickel acetate at the oxygen-containing group removal point are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0066] S4, stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between the single carbonized films to the graphitization furnace, use an 8kg graphite plate for natural load, raise the temperature to 1000℃ at a heating rate of 5℃ / min; then raise the temperature to 2600℃ middle zone temperature at a heating rate of 2℃ / min, keep warm for 2h; finally, raise the temperature to 2900℃ graphitization temperature at a heating rate of 0.5℃, keep warm for 1h. The entire graphitization process of this step uses high-purity argon gas for atmosphere protection. At the middle zone temperature, the anchor nickel source is extremely active and fluid. At the middle zone temperature, the anchor nickel source that has undergone a round of carburization and carbon precipitation absorbs oxygen-containing groups to fall off and form SP 3 Hybridized carbon source; when the graphene film enters the high-temperature graphitization temperature zone, the anchor nickel source uses its catalytic effect of carburization and carbon precipitation to promote the rearrangement of carbon atoms. At the same time, the nickel source volatilizes and precipitates carbon to provide a carbon source for the rearrangement of carbon atoms to repair defects. After the insulation is completed, it is cooled to room temperature to obtain a graphitized film, that is, a graphene thermal conductive film.

[0067] S5, testing the thermal diffusion coefficient of the graphene thermal conductive film obtained in step S4, such as Figure 3 As shown, the results show that its thermal diffusion coefficient is 918.967 mm 2 / s, Figure 5 This is the EDS image of the above graphene thermal conductive film. The EDS scanning image shows only C element and no Ni element, indicating that the anchor nickel source introduced by infiltration in step S2 has been completely volatilized in the graphitization stage, and the obtained thermal conductive film is a pure graphene thermal conductive film.

[0068] Figure 4: is a SEM picture of the above graphene thermal conductive film. It can be seen from the picture that the graphene thermal conductive film prepared in this embodiment has almost no defects and has a high degree of crystallinity.

[0069] Comparative Example 1

[0070] The difference between this comparative example and Example 1 is that there is no step S2, that is, no nickel source is introduced, and the graphene thermal conductive film is prepared by the traditional preparation process, the purpose of which is to explore the influence of the introduction of the nickel source on the thermal conductivity of the graphene thermal conductive film.

[0071] The results show that the thermal diffusion coefficient of the graphene thermal conductive film obtained in this comparative example is 799.960 mm 2 / s(such as Figure 6 As shown), this can be attributed to the fact that there is no nickel source introduced. Compared with the graphene thermal conductive film obtained in Example 1, the efficiency of repairing defects by promoting carbon atom rearrangement by pure high-temperature graphitization is low, resulting in more defects, which is not conducive to phonon transmission.

[0072] Comparative Example 2

[0073] The difference between this comparative example and comparative example 1 is that the temperature of the high temperature zone in the graphitization stage of step S4 is set to 3200° C., and its purpose is to explore the effect of only increasing the graphitization temperature on the performance of the graphene thermal conductive film without introducing a nickel source.

[0074] The results show that the thermal diffusion coefficient of the graphene thermal conductive film obtained in Comparative Example 2 is 812.654 mm 2 / s(such as Figure 7 ), which is lower than Example 1, and there is no significant improvement relative to Comparative Example 1. Comparing Comparative Example 1 with Example 1, it can be seen that Example 1 achieves a higher thermal diffusion coefficient at the same graphitization temperature; Comparative Example 2 is compared with Example 1, and Example 1 achieves a higher thermal diffusion coefficient at a lower graphitization temperature. This can be attributed to the fact that pure high-temperature graphitization cannot reduce the energy barrier of carbon atom rearrangement, and its defect repair efficiency is not high, which does not improve the thermal diffusion coefficient of the graphene thermal conductive film much.

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that in the pretreatment stage of step S1, only 10 kg load is used for film pressing, and the gaseous steps are the same as those in Example 1. The purpose is to study the effect of carbon source pretreatment film pressing load on the performance of graphene thermal conductive film.

[0077] The results show that the thermal diffusion coefficient of the graphene thermal conductive film obtained in this comparative example is 848.390 mm 2 / s(such as Figure 8This can be attributed to the fact that during the pretreatment stage, the graphene oxide film expands due to the shedding of oxygen-containing groups and the generation of gas. When the film pressure load is light, the graphene oxide film expands by a large multiple, resulting in the damage or cracking of some graphene sheets inside the graphene film, which is equivalent to introducing redundant defects to increase the scattering of phonons due to defects during the transmission process, which is not conducive to heat conduction.

[0078] Comparative Example 4

[0079] The difference between this comparative example and Example 1 is that in step S1, the graphene oxide films are cut and stacked, and graphite films are intercalated between the stacked single graphene oxide films, and then a square iron with a load capacity of 30 kg is loaded as a weight, and then step S2 is directly performed, that is, the graphene oxide film is not pretreated.

[0080] As a result, the graphene thermal conductive film could not be produced. This was because the graphene oxide film was not pretreated, and a large amount of gas was released simultaneously during the carbonization process, causing the film material to directly break and burn.

[0081] Comparative Example 5

[0082] The difference between this comparative example and Example 1 is that in the pretreatment of step S1, the carbonization treatment of step S3, and the graphitization treatment of step S4, no graphite film is inserted between the films to be treated, and the remaining steps are consistent with Example 1.

[0083] As a result, the graphene thermal conductive films that were not separated by the graphite film were stuck together and difficult to separate, which reduced industrial efficiency.

[0084] Example 2

[0085] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0086] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and a graphite film is intercalated between a single graphene oxide film and the substrate. Then, a square iron with a load of 30 kg is loaded as a weight. The loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 260°C at a heating rate of 1°C / min. The temperature is kept for 2 hours, and the pretreatment film is obtained after the temperature is naturally cooled to room temperature. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0087] S2. Use deionized water nickel nitrate to prepare a solution with a solid content of 8%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use an 8kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -98KPa, and continue to evacuate for 3 hours to allow the nickel acetate aqueous solution to infiltrate the pretreatment membrane through infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 150°C for 24 hours to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0088] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between the single Ni / pretreatment film and transfer the graphite plate with a load of 10kg to the carbonization furnace. Raise the temperature to 1300℃ at a heating rate of 1.5℃ / min in a nitrogen atmosphere and keep it warm for 2h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by the in-situ carbon etching and the carbon source cracked by nickel acetate at the oxygen-containing group removal point are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0089] S4, stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between the single carbonized films to the graphitization furnace, use an 8kg graphite plate for natural load, raise the temperature to 1000℃ at a heating rate of 5℃ / min; then raise the temperature to 2600℃ middle zone temperature at a heating rate of 2℃ / min, keep warm for 2h; finally, raise the temperature to 2900℃ graphitization temperature at a heating rate of 0.5℃, keep warm for 1h. The entire graphitization process of this step uses high-purity argon gas for atmosphere protection. At the middle zone temperature, the anchor nickel source is extremely active and fluid. At the middle zone temperature, the anchor nickel source that has undergone a round of carburization and carbon precipitation absorbs oxygen-containing groups to fall off and form SP 3 Hybridized carbon source; when the graphene film enters the high-temperature graphitization temperature zone, the anchor nickel source uses its catalytic effect of carburization and carbon precipitation to promote the rearrangement of carbon atoms. At the same time, the nickel source volatilizes and precipitates carbon to provide a carbon source for the rearrangement of carbon atoms to repair defects. After the insulation is completed, it is cooled to room temperature to obtain a graphitized film, that is, a graphene thermal conductive film.

[0090] S5, testing the thermal diffusion coefficient of the graphene thermal conductive film obtained in step S4, such as Fig. 9 As shown, the results show that its thermal diffusion coefficient is 874.935mm 2 / s. In the carbonization stage, the anchor nickel source can only absorb the gaseous carbon source formed by the in-situ carbon etching accompanying the removal of oxygen-containing groups, and no carbon source cracked by nickel acetate is absorbed by the anchored nickel source. Compared with Example 1, the anchor nickel source absorbs less carbon source during carburization, and the subsequent nickel source volatilization and carbon precipitation provide relatively less carbon source for repairing defects.

[0091] Example 3

[0092] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0093] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and a graphite film is inserted between the stacked single graphene oxide film and the substrate. Then, a square iron with a load of 20 kg is loaded as a weight, and the loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 400°C at a heating rate of 2°C / min, and the temperature is kept for 4 hours. After naturally cooling to room temperature, a pretreated film is obtained. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0094] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 10%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use a 10kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -100KPa, and continue to evacuate for 4 hours to allow the nickel acetate aqueous solution to infiltrate the pretreatment membrane through infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 200°C for 16 hours to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0095] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between the single Ni / pretreatment film and transfer the graphite plate with a load of 20 kg to the carbonization furnace. Raise the temperature to 1350°C at a heating rate of 2°C / min in a nitrogen atmosphere and keep it warm for 6 hours. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by the in-situ carbon etching and the carbon source cracked by nickel acetate at the oxygen-containing group removal point are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0096] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between the single carbonized films to a graphitization furnace, use a 20 kg graphite plate for natural load, and raise the temperature to 1000°C at a heating rate of 5°C / min; then raise the temperature to a middle zone temperature of 2700°C at a heating rate of 5°C / min, and keep it warm for 3 hours; finally, raise the temperature to a graphitization temperature of 3300°C at a heating rate of 1°C, keep it warm for 3 hours, and cool to room temperature after the insulation is completed to obtain a graphitized film, i.e., a graphene thermal conductive film.

[0097] Example 4

[0098] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0099] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and a graphite film is inserted between the stacked single graphene oxide films and the substrate. Then, a square iron with a load of 20 kg is loaded as a weight, and the loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 200°C at a heating rate of 0.2°C / min, and the temperature is kept for 1 hour. After naturally cooling to room temperature, a pretreated film is obtained. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0100] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 1%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use a 10kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -90KPa, and continue to evacuate for 1h, so that the nickel acetate aqueous solution is infiltrated into the pretreatment membrane by infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 100°C for 20h to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0101] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between the single Ni / pretreatment film and transfer the graphite plate with a load of 5kg to the carbonization furnace. Raise the temperature to 1000℃ at a heating rate of 0.5℃ / min in a nitrogen atmosphere and keep it warm for 1h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by the in-situ carbon etching and the carbon source cracked by nickel acetate at the oxygen-containing group removal point are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0102] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between the single carbonized films to a graphitization furnace, use a 20 kg graphite plate for natural load, and raise the temperature to 1000°C at a heating rate of 5°C / min; then raise the temperature to a middle zone temperature of 2500°C at a heating rate of 1°C / min, and keep it warm for 1 hour; finally, raise the temperature to a graphitization temperature of 2800°C at a heating rate of 0.5°C, keep it warm for 0.5 hour, and cool to room temperature after the insulation to obtain a graphene thermal conductive film.

[0103] Example 5

[0104] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0105] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and a graphite film is intercalated between the stacked single graphene oxide films and the substrate. Then, a square iron with a load of 20 kg is loaded as a weight, and the loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 300°C at a heating rate of 1°C / min, and the temperature is kept for 3 hours. After naturally cooling to room temperature, a pretreated film is obtained. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0106] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 5%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use a 10kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -95KPa, and continue to evacuate for 3 hours to allow the nickel acetate aqueous solution to infiltrate the pretreatment membrane through infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 160°C for 17 hours to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0107] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between the single Ni / pretreatment film and transfer the graphite plate with a load of 15kg to the carbonization furnace. Raise the temperature to 1200℃ at a heating rate of 1℃ / min in a nitrogen atmosphere and keep it warm for 3h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by the in-situ carbon etching and the carbon source cracked by nickel acetate at the oxygen-containing group removal point are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0108] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between the single carbonized films to a graphitization furnace, use a 20 kg graphite plate for natural load, and raise the temperature to 1000 ° C at a heating rate of 5 ° C / min; then raise the temperature to 2600 ° C middle zone temperature at a heating rate of 3 ° C / min, and keep it warm for 2 hours; finally, raise the temperature to 3000 ° C graphitization temperature at a heating rate of 0.5 ° C, keep it warm for 2 hours, and cool to room temperature after the insulation to obtain a graphitized film, i.e., a graphene thermal conductive film.

[0109] The performance characteristics of the graphene thermal conductive films prepared in Examples 2-4 are consistent with those in Example 1 and will not be repeated here.

[0110] Example 6

[0111] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0112] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and a graphite film is inserted between the three stacked graphene oxide films. Then, a square iron with a load of 30 kg is loaded as a weight. The loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 260°C at a heating rate of 1°C / min, and the temperature is kept for 2 hours. After naturally cooling to room temperature, a pretreated film is obtained. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0113] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 8%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use an 8kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -98KPa, and continue to evacuate for 3h, so that the nickel acetate aqueous solution is infiltrated into the pretreatment membrane by infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 150°C for 24h to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0114] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between three Ni / pretreatment films and transfer the graphite plate loaded with 10kg to the carbonization furnace. Raise the temperature to 1300℃ at a heating rate of 1.5℃ / min in a nitrogen atmosphere and keep it warm for 2h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by in-situ carbon etching and the carbon source cracked by nickel acetate at the point where the oxygen-containing groups are removed are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0115] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between a single or multiple carbonized films to a graphitization furnace, use an 8Kg graphite plate for natural load, and raise the temperature to 1000°C at a heating rate of 5°C / min; then raise the temperature to a middle zone temperature of 2600°C at a heating rate of 2°C / min, and keep it warm for 2h; finally, raise the temperature to a graphitization temperature of 2900°C at a heating rate of 0.5°C, keep it warm for 1h, and cool to room temperature after the insulation to obtain a graphitized film, i.e., a graphene thermal conductive film.

[0116] Example 7

[0117] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0118] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and graphite films are intercalated between the 15 stacked graphene oxide films. Then, a square iron with a load of 30 kg is loaded as a weight. The loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 260°C at a heating rate of 1°C / min, and the temperature is kept for 2 hours. After naturally cooling to room temperature, a pretreated film is obtained. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0119] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 8%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use an 8kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -98KPa, and continue to evacuate for 3h, so that the nickel acetate aqueous solution is infiltrated into the pretreatment membrane by infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 150°C for 24h to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0120] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between three Ni / pretreatment films and transfer the graphite plate loaded with 10kg to the carbonization furnace. Raise the temperature to 1300℃ at a heating rate of 1.5℃ / min in a nitrogen atmosphere and keep it warm for 2h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by in-situ carbon etching and the carbon source cracked by nickel acetate at the point where the oxygen-containing groups are removed are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0121] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between a single or multiple carbonized films to a graphitization furnace, use an 8Kg graphite plate for natural load, and raise the temperature to 1000°C at a heating rate of 5°C / min; then raise the temperature to a middle zone temperature of 2600°C at a heating rate of 2°C / min, and keep it warm for 2h; finally, raise the temperature to a graphitization temperature of 2900°C at a heating rate of 0.5°C, keep it warm for 1h, and cool to room temperature after the insulation to obtain a graphitized film, i.e., a graphene thermal conductive film.

[0122] Example 8

[0123] A method for preparing a nickel-catalyzed defect-repairing graphene thermal conductive film, the specific steps are as follows:

[0124] S1. The raw materials used are conventional graphene oxide dry films purchased from Yuntian Mo Rui. The graphene oxide films are cut and stacked, and graphite films are intercalated between the 33 stacked graphene oxide films. Then, a square iron with a load of 30 kg is loaded as a weight. The loaded graphene oxide film is transferred to a blast oven, and the temperature is raised to a pretreatment temperature of 260°C at a heating rate of 1°C / min, and the temperature is kept for 2 hours. After naturally cooling to room temperature, a pretreated film is obtained. The pretreatment in this step will remove some oxygen-containing groups from the graphene oxide dry film. The removal of oxygen-containing groups will produce gas, which will oxidize and expand the graphene film, resulting in an increase in thickness, and form a large number of microporous structures in the cross section.

[0125] S2. Use deionized water to prepare nickel acetate tetrahydrate into a solution with a solid content of 8%, immerse the pretreatment membrane obtained in step S1 in the nickel acetate aqueous solution, and use a 8kg weight to press on the pretreatment membrane. Transfer the nickel acetate solution without the pretreatment membrane to a vacuum oven, set the vacuum degree to -98KPa, and continue to evacuate for 3h, so that the nickel acetate aqueous solution is infiltrated into the pretreatment membrane by infiltration. After the infiltration is completed, the pretreatment membrane is laid flat and transferred to a blast oven and baked at 150°C for 24h to remove the moisture of the pretreatment membrane to obtain a Ni / pretreatment membrane.

[0126] S3. After stacking the Ni / pretreatment film obtained in step S2, insert a graphite film between three Ni / pretreatment films and transfer the graphite plate loaded with 10kg to the carbonization furnace. Raise the temperature to 1300℃ at a heating rate of 1.5℃ / min in a nitrogen atmosphere and keep it warm for 2h. In this step, the Ni / pretreatment film basically removes all oxygen-containing groups. The gaseous carbon source formed by in-situ carbon etching and the carbon source cracked by nickel acetate at the point where the oxygen-containing groups are removed are absorbed by the anchored nickel source, and the anchor nickel source obtains the first round of carburization and carbon precipitation. After naturally cooling to room temperature, the carbonization treatment is completed to obtain a carbonized film.

[0127] S4. Stack the carbonized films obtained in step S3, and transfer the intercalated graphite films between a single or multiple carbonized films to a graphitization furnace, use an 8Kg graphite plate for natural load, and raise the temperature to 1000°C at a heating rate of 5°C / min; then raise the temperature to a middle zone temperature of 2600°C at a heating rate of 2°C / min, and keep it warm for 2h; finally, raise the temperature to a graphitization temperature of 2900°C at a heating rate of 0.5°C, keep it warm for 1h, and cool to room temperature after the insulation to obtain a graphitized film, i.e., a graphene thermal conductive film.

[0128] The graphene thermal conductive films prepared in Examples 6-8 are thicker than those in Example 1, and other performance characteristics are consistent with those in Example 1, which will not be described here.

[0129] Example 9

[0130] A heat dissipation device comprises the graphene thermal conductive film prepared in Example 1.

[0131] Example 10

[0132] An electronic device comprises the heat dissipation device described in Example 9.

[0133] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for preparing a nickel-catalyzed defect-repairing graphene thermally conductive film, characterized in that: include: Pretreatment: removing some oxygen-containing groups of the graphene oxide film by pretreatment to obtain a pretreated film; Introducing a nickel source: Under vacuum conditions, introducing an aqueous electrolytic nickel source into the pretreatment film by solvent infiltration to obtain a Ni / pretreatment film; Carbonization treatment: carbonizing the Ni / pre-treated film to obtain a carbonized film; Graphitization treatment: graphitizing the carbonized film to obtain the graphene thermal conductive film.

2. The preparation method according to claim 1, characterized in that: In the pretreatment and / or carbonization treatment and / or graphitization treatment steps, the films to be treated are stacked, and graphite films are inserted between the stacked single films to be treated.

3. The preparation method according to claim 1, characterized in that: The pre-processing step specifically includes: The graphene oxide film is pretreated at low temperature under a load, wherein the temperature of the low temperature pretreatment is 200-400° C., the heating rate is 0.2-2° C. / min, and the temperature is kept for 1-4 hours; The weight of the load is ≥ 20 kg.

4. The preparation method according to claim 1, characterized in that: The steps of introducing the nickel source specifically include: The pretreated membrane is loaded and immersed in the aqueous electrolytic nickel source, and vacuumed for 1-4 hours, with the vacuum degree set in the range of -100 KPa to -90 KPa.

5. The preparation method according to claim 1, characterized in that: The carbonization treatment step specifically includes: After the Ni / pre-treated film is loaded, the temperature is raised to 1000-1350° C. at a heating rate of 0.5-2° C. / min in an inert gas atmosphere, and kept at this temperature for 1-6 hours; The Ni / pretreatment film load weight is ≥5kg.

6. The preparation method according to claim 1, characterized in that: The graphitization treatment step specifically includes: After the carbonized film is loaded, in an inert gas atmosphere, the temperature is raised to the low temperature zone at a heating rate of 5°C / min, then raised to the medium temperature zone at a heating rate of 1-5°C / min, and kept warm for 1-3h; finally, the temperature is raised to the high temperature zone at a heating rate of 0.5-1°C, and kept warm for 0.5-3h.

7. The preparation method according to claim 6, characterized in that: The temperature of the low temperature zone is 900-1100°C; The temperature of the medium temperature zone is 2500-2700°C; The temperature in the high temperature zone is 2800-3300°C.

8. A nickel-catalyzed defect-repairing graphene thermally conductive film, characterized in that: Thermal diffusivity is 860 mm 2 / s or more, nickel-free, pure graphene thermal conductive film; It is prepared by the preparation method according to any one of claims 1 to 7.

9. A heat dissipation device, characterized in that: The graphene thermally conductive film is prepared by the preparation method described in any one of claims 1 to 7 or the graphene thermally conductive film described in claim 8.

10. An electronic device, characterized in that: The graphene thermal conductive film or the graphene thermal conductive film of claim 8 or the heat dissipation device of claim 9 is prepared by the preparation method of any one of claims 1 to 7.

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