A high-temperature-resistant, high-conductivity and deep-low-temperature high-conductivity carbon film and a preparation method thereof
By inserting molybdenum chloride layers between graphene sheets, the problems of thermal conductivity degradation and structural instability of carbon-based thin films under extreme temperature environments have been solved, realizing carbon film materials with high electrical and thermal conductivity and resistance to low-temperature shock, which are suitable for thermal management in extreme environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2023-09-27
- Publication Date
- 2026-06-02
AI Technical Summary
Existing carbon-based thin film materials exhibit a sharp decline in thermal conductivity at deep and low temperatures and are structurally and functionally unstable in extreme temperature alternation environments. This makes it impossible to precisely control the electron acceptor content, leading to the failure of thermal management materials.
By employing a dual-temperature-zone gas-phase composite electron acceptor technology, a molybdenum chloride layer is inserted between graphene sheets as an electron acceptor. By controlling the ratio of MoO3 and MoCl5 and the temperature zone, a carbon film with high electrical conductivity and high thermal conductivity at deep low temperatures is prepared.
It improves the electrical conductivity and cryogenic thermal conductivity of carbon films, maintains the structural stability and performance of materials under frequent high and low temperature alternation environments, increases electrical conductivity by 2-10 times, improves cryogenic thermal conductivity by 4.6 times, and has good mechanical and chemical stability.
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Figure CN117265527B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional materials technology, and in particular to a highly conductive and deep-temperature highly thermally conductive carbon film resistant to frequent alternation of high and low temperatures, and its preparation method. Background Technology
[0002] The trend towards integration and miniaturization of electronic devices has placed higher demands on thermal management. As exploration of extreme environments such as Antarctica, the Moon, and Mars deepens, extreme conditions are constantly emerging, such as alternating periods of extreme cryogenic and ultra-low temperature, becoming major obstacles to further exploration. Especially under these extreme conditions, the physicochemical properties of materials can change, even causing the failure of critical components and equipment. This places additional demands on the materials used. Traditional thermally conductive metals, such as copper and aluminum, have good mechanical properties but suffer from drawbacks such as high density and susceptibility to corrosion. In contrast, carbon-based thin film materials have become highly attractive due to their excellent thermal transport properties, outstanding thermal stability, inherent chemical resistance, and superior flexibility. Currently, the fastest-developing carbon-based thin film thermal management materials mainly include polyimide-based graphite films and graphene films.
[0003] As an emerging high-efficiency heat dissipation material, carbon-based thermal conductive films have been effectively applied in various fields at room temperature, such as high-power lasers, semiconductor device packaging, MEMS, and chip heat dissipation. However, the performance of high thermal conductivity carbon films often exhibits a sharp decline at deep cryogenic temperatures. At the same time, carbon films with thermal and chemical stability in extreme temperature alternating environments often lack structural and performance stability under cryogenic shock, leading to their failure as thermal management materials.
[0004] Currently, increasing the electron acceptor concentration and mobility of carbon materials through chemical methods to enhance their thermal conductivity during cryogenic insertion is an effective approach. However, existing technologies cannot achieve precise control over the electron acceptor content. Furthermore, current techniques often require prolonged high-temperature reactions to achieve effective insertion, resulting in high energy consumption and low efficiency. Summary of the Invention
[0005] The purpose of this invention is to improve the structural damage and performance loss of high thermal conductivity carbon films under frequent temperature alternation environments, and to provide a carbon film with high thermal conductivity and stable performance at deep low temperatures and its preparation method.
[0006] The present invention adopts the following technical solution:
[0007] A highly conductive and deeply thermally conductive carbon film resistant to frequent alternation of high and low temperatures includes a carbon film body, wherein the carbon film acts as an electron donor, the carbon film body is composed of multiple graphene sheets, and a molybdenum chloride layer is inserted between two adjacent graphene sheets, wherein the molybdenum chloride layer is inserted between the graphene sheets in the form of an ionic compound as an electron acceptor.
[0008] Preferably, the thickness of the molybdenum chloride layer is 0.90-0.95 nm.
[0009] Preferably, the carbon film body is selected from polyimide-based graphite film, graphene film, and artificial graphite film.
[0010] A method for preparing the above-mentioned highly conductive and deeply low-temperature highly thermally conductive carbon film resistant to frequent alternation of high and low temperatures, the method comprising:
[0011] Using dual-temperature zone gas-phase composite electron acceptor technology, a certain proportion of catalysts MoO3 and MoCl5 are used as electron acceptors and sealed in a closed cavity without direct contact with a carbon film as an electron donor. The film is heated in a dual-temperature zone to obtain a carbon film with high electrical conductivity and high thermal conductivity at deep low temperature that can withstand frequent alternation of high and low temperatures.
[0012] The mass ratio of carbon film to MoCl5 is 1:21.6, 1:2.5 or 1:0.6, and the molar ratio of MoO3 to MoCl5 is 0.34, 0.48 and 0.62, respectively, which correspond to the preparation of first-level, second-level and fourth-level carbon films with high electrical conductivity and high thermal conductivity at deep low temperature that are resistant to frequent alternation of high and low temperatures.
[0013] The dual temperature zones are 230°C for the carbon film and 200°C for the MoO3 and MoCl5.
[0014] This method employs a dual-temperature-zone gas-phase composite electron acceptor technique to gently and non-destructively insert molybdenum chloride into the interlayer of a highly graphitized carbon film at a specific ratio. The combination of electron-donating carbon and the electron-withdrawing compound molybdenum chloride results in a carbon film with conductivity an order of magnitude higher than the original film, reaching the conductivity levels of most metallic materials. Simultaneously, the increased charge carriers enhance the contribution of electron thermal conductivity at cryogenic temperatures, allowing the thermal conductivity at cryogenic temperatures to reach up to 4.6 times that of the original carbon film. Furthermore, the high binding energy between molybdenum chloride and graphene sheets ensures that the structure and properties remain stable and excellent even after frequent high- and low-temperature shocks. The preparation method is simple and controllable, achieving improved conductivity and cryogenic thermal conductivity of the carbon film, resulting in a carbon-based thermal management material that can withstand cryogenic shocks in extreme environments and exhibits stable performance. The carbon-based thermally conductive film prepared by this method has broad application prospects in extreme temperature heat dissipation fields such as aerospace and deep-sea exploration.
[0015] Preferably, the degree of graphitization of the carbon film serving as the electron donor is above 90%.
[0016] Preferably, the sealed cavity is a vacuum, and the vacuum level is not less than 10. 4 mbar.
[0017] The aforementioned carbon film, which is resistant to frequent high and low temperature alternation, has high electrical conductivity and high thermal conductivity at deep low temperatures. It not only has the advantages of high electrical conductivity, high thermal conductivity at deep low temperatures, high flexibility, and low density, but also maintains its original good morphology and excellent properties after frequent high and low temperature alternation. It has excellent resistance to temperature alternation (-196℃~180℃) and performance stability (thermal conductivity retention rate ≥90%).
[0018] The carbon film of this invention has a conductivity of 10. 7 The thermal conductivity is on the order of S / m, comparable to that of metallic materials; the thermal conductivity at deep low temperature (4K) can reach 12W / mK, which is ~4.6 times that of the original carbon film; the structure does not suffer damage after frequent temperature changes and the thermal and electrical conductivity is well maintained.
[0019] The beneficial effects of this invention are as follows:
[0020] (1) The conductivity of the carbon film of the present invention can be increased by 2-10 times compared with carbon film materials without electron acceptors, and its specific conductivity can be comparable to or even exceed that of most metal materials.
[0021] (2) The thermal conductivity of the carbon film deep low temperature (4K) of the present invention can be improved by ~4.6 times compared with the carbon film material without electron acceptor.
[0022] (3) Due to the strong bonding force between molybdenum chloride and graphene layers, it has stable properties such as solvent resistance and low temperature resistance, and exhibits dual stability of structure and performance under extreme temperature frequent alternation (-196℃~180℃).
[0023] (4) The carbon film prepared by the present invention does not affect the inherent flexibility of the carbon film, so it still has good mechanical stability and can withstand complex deformation for a long time.
[0024] (5) The carbon film obtained by the present invention has the characteristics of high electrical conductivity, high thermal conductivity at deep low temperature, high flexibility and low density. At the same time, the preparation process is simple, the raw materials are readily available, and it can be mass-produced. It can produce carbon-based thermal management materials with large size, easy shape design, stable performance and excellent performance in extreme environments. Attached Figure Description
[0025] Figure 1 This is a schematic diagram illustrating the preparation of a highly conductive and deeply thermally conductive carbon film that is resistant to frequent alternation of high and low temperatures, as shown in one embodiment.
[0026] Figure 2This is a schematic diagram of the carbon film structure after electron donor-acceptor recombination, as shown in one embodiment.
[0027] Figure 3 This is a comparison diagram of the conductivity before and after electron donor-acceptor recombination, provided in one embodiment.
[0028] Figure 4 This is a morphological image of a carbon film after low-temperature impaction before and after electron donor-acceptor recombination, as shown in one embodiment.
[0029] Figure 5 This is a comparison of thermal conductivity at deep cryogenic (4K) before and after electron donor-acceptor recombination and before and after cryogenic shock, as shown in an embodiment. Detailed Implementation
[0030] The present invention will be specifically described below through embodiments. These embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential changes and adjustments made by those skilled in the art based on the above-described invention are within the scope of protection of the present invention.
[0031] Example 1:
[0032] 0.192 g of graphene film with a graphitization degree >90%, 0.7428 g of MoO3, and 4.1472 g of MoCl5 were placed at both ends of a glass reaction tube. The tube was then evacuated and sealed, with a vacuum degree greater than 10. 4 mbar. For example... Figure 1 The reaction tube was placed in a dual-temperature zone tube furnace, with the temperature zone containing the carbon film controlled at 230℃ and the temperature zone containing MoO3 and MoCl5 controlled at 200℃, and the reaction was carried out for 48 hours. After cooling, a primary molybdenum chloride electron donor-acceptor composite graphene film (GF-MoCl5-1) with alternating graphene and molybdenum chloride layers was obtained. This material exhibits high flexibility, can withstand repeated bending, and Raman characterization showed I... D / I G =0.04, indicating that the composite product did not produce obvious defects, and the original good crystal structure of the carbon film was not destroyed; it has high conductivity, with a conductivity greater than 10. 7 S / m; thermal conductivity improved by 150% at deep low temperature (4K); chemically resistant, maintaining good performance after being immersed in organic reagents for one month; resistant to temperature alternation, maintaining good structure and performance after 50 liquid nitrogen shocks (LNS).
[0033] Example 2:
[0034] 0.213g of graphene film with a graphitization degree >90%, 0.1347g of MoO3, and 0.5325g of MoCl5 were placed at both ends of a glass reaction tube. The tube was then evacuated and sealed, with a vacuum degree greater than 10. 4 mbar. For example... Figure 1 The reaction tube was placed in a dual-temperature zone tube furnace, with the temperature zone containing the carbon film controlled at 230℃ and the temperature zone containing MoO3 and MoCl5 controlled at 200℃, and the reaction was carried out for 48 hours. Figure 2 After cooling, a secondary molybdenum chloride electron donor-acceptor composite graphene film (GF-MoCl5-2) with alternating layers of graphene and molybdenum chloride was obtained. This material exhibits high flexibility and can withstand repeated bending. Raman characterization showed... D / I G =0.02, indicating that the composite product did not produce obvious defects, and the original good crystal structure of the carbon film was not destroyed; it has high conductivity, with a conductivity greater than 10. 7 S / m; thermal conductivity improved by 360% at deep low temperature (4K); chemically resistant, maintaining good performance after being immersed in organic reagents for one month; resistant to temperature alternation, maintaining good structure and performance after 50 liquid nitrogen shocks (LNS).
[0035] Example 3:
[0036] 0.200g of graphene film with a graphitization degree >90%, 0.039g of MoO3, and 0.12g of MoCl5 were placed at both ends of a glass reaction tube. The tube was then evacuated and sealed, with a vacuum degree greater than 10. 4 mbar. For example... Figure 1 The reaction tube was placed in a dual-temperature zone tube furnace, with the temperature zone containing the carbon film controlled at 230℃ and the temperature zone containing MoO3 and MoCl5 controlled at 200℃, and the reaction was carried out for 48 hours. After cooling, a quadrature molybdenum chloride electron donor-acceptor composite graphene film (GF-MoCl5-4) with alternating four graphene layers and one molybdenum chloride layer was obtained. This material exhibits high flexibility, can withstand repeated bending, and Raman characterization showed I... D / I G =0.01, indicating that the composite product did not produce obvious defects, and the original good crystal structure of the carbon film was not destroyed; it has high conductivity, with a conductivity greater than 10. 7 S / m; thermal conductivity improved by 270% at deep low temperature (4K); chemically resistant, maintaining good performance after being immersed in organic reagents for one month; resistant to temperature alternation, maintaining good structure and performance after 50 liquid nitrogen shocks (LNS).
[0037] Example 4:
[0038] 0.17g of polyimide graphite film with a graphitization degree >90%, 0.1075g of MoO3, and 0.425g of MoCl5 were placed at both ends of a glass reaction tube. The tube was then evacuated and sealed, with a vacuum level greater than 10. 4 mbar. For example... Figure 1The reaction tube was placed in a dual-temperature zone tube furnace, with the temperature zone containing the carbon film controlled at 230℃ and the temperature zone containing MoO3 and MoCl5 controlled at 200℃, and the reaction was carried out for 48 hours. Figure 2 After cooling, a secondary molybdenum chloride electron donor-acceptor composite polyimide graphite film (GF-MoCl5-2) with alternating layers of graphene and molybdenum chloride was obtained. This material exhibits high flexibility, can withstand repeated bending, and Raman characterization showed I... D / I G =0.01, indicating that the composite product did not produce obvious defects, and the original good crystal structure of the carbon film was not destroyed; it has high conductivity, with a conductivity greater than 10. 7 S / m; thermal conductivity improved by 330% at deep low temperature (4K); chemically resistant, maintaining good performance after being immersed in organic reagents for one month; resistant to temperature alternation, maintaining good structure and performance after 50 liquid nitrogen shocks (LNS).
[0039] Comparative Example 1:
[0040] This example is the same as in Example 4, except that: no electron donor-acceptor complexation was performed, and Raman characterization was performed. D / I G =0.01, indicating that the uncomposite carbon film has a good crystal structure and few defects; the conductivity of the polyimide graphite film is 1.1×10 6 S / m, the thermal conductivity at extremely low temperatures (4K) is only 2.6 W / mK, such as Figure 4 The structure was significantly damaged after 50 liquid nitrogen shocks (LNS), and the thermal conductivity at deep cryogenic temperature (4K) decreased by 50%.
[0041] Comparative Example 2:
[0042] 0.3g of graphene film with a graphitization degree >90% was placed in a glass reaction tube along with 0.1g of MoO3 and 0.3g of MoCl5. The tube was then evacuated and sealed, with a vacuum degree greater than 10. 4 mbar. The reaction temperature was 300℃, and the reaction time was 7 days. After cooling, a molybdenum chloride electron donor-acceptor composite graphene film (GF-MoCl5) with alternating graphene and molybdenum chloride layers of varying numbers was obtained. This material exhibits high flexibility and can withstand repeated bending; Raman characterization I D / I G =0.13, indicating that defects were introduced into the composite product, and the original good crystal structure of the carbon film was destroyed; it has high conductivity, with a conductivity greater than 10. 7 S / m; thermal conductivity at deep low temperature (4K) is not significantly improved; it has chemical resistance and its performance remains good after being soaked in organic reagents for one month; it has poor resistance to temperature alternation and its structure and performance are damaged after 50 liquid nitrogen shocks (LNS).
[0043] Comparative Example 3:
[0044] This example is similar to Comparative Example 2, except that the reaction temperature was 300℃ and the reaction time was 2 days. After cooling, the resulting graphene film did not show the characteristic peak of molybdenum chloride under XRD characterization. The conductivity was 1.3 × 10⁻⁶. 6 S / m; The thermal conductivity at deep cryogenic temperature (4K) was not improved and it lacked resistance to temperature cycling; after 50 liquid nitrogen shocks (LNS), the structure and properties could not be well maintained. This indicates that effective electron donor-electron acceptor recombination cannot be achieved under these reaction conditions.
[0045] Comparative Example 4:
[0046] This example is similar to Comparative Example 2, except that the reaction temperature was 230℃ and the reaction time was 7 days. After cooling, the resulting graphene film did not show the characteristic peak of molybdenum chloride under XRD characterization. The conductivity was 1.3 × 10⁻⁶. 6 S / m; The thermal conductivity at deep cryogenic temperature (4K) was not improved and it lacked resistance to temperature cycling; after 50 liquid nitrogen shocks (LNS), the structure and properties could not be well maintained. This indicates that effective electron donor-electron acceptor recombination cannot be achieved under these reaction conditions.
[0047] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.
[0048] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A method for preparing a highly conductive and deeply thermally conductive carbon film resistant to frequent alternation of high and low temperatures, characterized in that, The method includes: Using dual-temperature zone gas-phase composite electron acceptor technology, a certain proportion of catalysts MoO3 and MoCl5 are used as electron acceptors and sealed in a closed cavity without direct contact with a carbon film as an electron donor. The film is heated in a dual-temperature zone to obtain a carbon film with high electrical conductivity and high thermal conductivity at deep low temperature that can withstand frequent alternation of high and low temperatures. The mass ratio of carbon film to MoCl5 is 1:21.6, 1:2.5 or 1:0.6, and the molar ratio of MoO3 to MoCl5 is 0.34, 0.48 and 0.62, respectively, which correspond to the preparation of first-level, second-level and fourth-level carbon films with high electrical conductivity and high thermal conductivity at deep low temperature that are resistant to frequent alternation of high and low temperatures. The dual temperature zones consist of a carbon film temperature zone of 230 °C and a MoO3 and MoCl5 temperature zone of 200 °C, with a reaction time of 48 h. The graphitization degree of the carbon film, which serves as an electron donor, is over 90%. The closed cavity is vacuum, and the vacuum degree is not less than 10 4 mbar.
2. A carbon film with high electrical conductivity and high thermal conductivity at deep low temperatures, prepared by the method described in claim 1, characterized in that, The highly conductive and thermally conductive carbon film, which is resistant to frequent alternation of high and low temperatures, includes a carbon film body. The carbon film body acts as an electron donor and is composed of multiple graphene sheets. A molybdenum chloride layer is inserted between two adjacent graphene sheets. The molybdenum chloride layer is inserted between the graphene sheets in the form of an ionic compound as an electron acceptor.
3. The highly conductive and deep-temperature-resistant carbon film with high electrical conductivity and high thermal conductivity resistant to frequent high and low temperature alternation according to claim 2, characterized in that, The thickness of the molybdenum chloride layer is 0.90-0.95 nm.
4. The carbon film with high electrical conductivity and high thermal conductivity at deep low temperatures that is resistant to frequent alternation of high and low temperatures according to claim 2, characterized in that, The carbon film body is selected from polyimide-based graphite film, graphene film and artificial graphite film.
5. The application of a highly conductive and thermally conductive carbon film resistant to frequent alternation of high and low temperatures prepared by the preparation method of claim 1 in heat dissipation in extreme low temperature fields, wherein the extreme low temperature fields are aerospace and deep-sea exploration.