A new type of hierarchical graphite material and a preparation method thereof
By constructing a three-dimensional interconnected graphene framework and using programmed cooling curing technology, a novel graded graphite material was prepared, achieving high thermal conductivity, rapid thermal response, and long-term stability. This solved the problems of single heat conduction path and slow response of traditional graphite materials in the field of thermal management.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JUNHENG ENERGY TECH (SANMING) CO LTD
- Filing Date
- 2026-02-06
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional graphite materials are difficult to achieve rapid thermal response and multi-level structural design in the field of thermal management, resulting in a single heat conduction path, slow response and poor long-term stability.
A three-dimensional interconnected graphene framework was constructed using a foam metal template. Combined with vacuum immersion and molecular self-assembly technology, a responsive phase change solution was precisely loaded into the framework, and a stable composite structure was formed through programmed cooling and curing.
A novel graded graphite material with a thermal conductivity ≥10.9 W·m⁻¹·K⁻¹ was prepared, exhibiting rapid thermal response and high thermal conductivity. It retains more than 96% of its thermal conductivity after 1000 thermal cycles, thus solving the technical bottleneck of traditional composite materials.
Abstract
Description
Technical Field
[0001] This invention relates to the field of new materials technology, and in particular to a novel graded graphite material and its preparation method. Background Technology
[0002] Graphite materials, due to their excellent electrical and thermal conductivity and chemical stability, have shown great application potential in energy, electronics, and thermal management. Traditional graphite materials, such as expanded graphite or graphene films, are mainly prepared through physical or chemical methods, and their structures are usually relatively simple, which limits their application in high-performance composite materials. In the field of thermal management, materials not only need high thermal conductivity for rapid heat dissipation, but also the ability to regulate the heat conduction pathway within a specific temperature range to prevent thermal runaway. Traditional graphite materials struggle to achieve this thermal response.
[0003] Currently, combining graphene with phase change materials can improve the functionality of graphite materials to some extent. However, simple physical blending makes it difficult to achieve uniform and localized loading of phase change materials in the graphene network, which can easily lead to performance degradation during use. Furthermore, the internal structure of the material is random and disordered, lacking multi-level and ordered structural design. Summary of the Invention
[0004] To address the aforementioned problems, this invention proposes a novel graded graphite material and its preparation method. This novel graphite material has a precisely controllable multi-level structure and can generate a rapid and significant response to changes in external temperature.
[0005] The present invention proposes a method for preparing a novel graded graphite material, comprising the following steps:
[0006] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network is grown on a foam metal template using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the foam metal template is removed with an etching solution to obtain a three-dimensional porous graphene framework.
[0007] Step 2: Dissolve the thermoplastic polymer and phase change paraffin in toluene, stir to dissolve, and form a responsive phase change solution;
[0008] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface.
[0009] Step 4: Perform programmed cooling and curing on the self-assembled composite material;
[0010] Step 5: Remove the cured material and remove any residual solution from the surface to obtain a new type of graded graphite material.
[0011] Preferably, in step 1, the pore size of the foam metal template is 100-500 μm, and the foam metal template is foam nickel or foam copper.
[0012] Preferably, the corrosive solution in step 1 is a hydrochloric acid solution or a ferric chloride solution.
[0013] Preferably, in step 1, the temperature at which the etchant removes the metal template is a 40-80°C water bath.
[0014] Preferably, the thermoplastic polymer in step 2 is polystyrene or polymethyl methacrylate.
[0015] Preferably, in step 2, the mass ratio of thermoplastic polymer to phase change paraffin is 1:(5-20).
[0016] Preferably, the melting point of the phase change paraffin in step 2 is 25-60℃.
[0017] Preferably, the self-assembly temperature in step 3 is 40-70℃ and the time is 2-12 h.
[0018] Preferably, the cooling and curing method in step 4 is as follows: first, the temperature is lowered from the solution clearing point temperature to 5-10℃ at a rate of 0.5-1℃ / min, and kept at that temperature for 1-4 hours, and then the temperature is lowered to room temperature at a rate of 2-5℃ / min.
[0019] The present invention proposes a novel graded graphite material, which is prepared by the above-described preparation method.
[0020] The beneficial effects of this invention are:
[0021] This invention successfully prepared a novel hierarchical graphene material by constructing a three-dimensional interconnected graphene framework using foamed metal as a template, then precisely loading a responsive phase change solution into the framework using vacuum immersion and molecular self-assembly techniques, and finally solidifying it through programmed cooling to form a stable composite structure. The material exhibits a thermal conductivity ≥10.9 W·m⁻¹·K⁻¹ and a characteristic response time t90 as short as 10⁵ s, achieving superior performance by combining high thermal conductivity, rapid thermal response, and thermal regulation. Furthermore, thanks to its robust hierarchical structure, it retains over 96% of its thermal conductivity after 1000 thermal cycles, overcoming the technical bottlenecks of traditional composite materials, such as single thermal conduction paths, slow response, and poor long-term stability. Detailed Implementation
[0022] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.
[0023] Example 1:
[0024] This embodiment describes a method for preparing a novel graded graphite material, comprising the following steps:
[0025] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network was grown on nickel foam with a pore size of 100 μm using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the metal template was removed with 2 mol / L hydrochloric acid solution in a 40℃ water bath to obtain a three-dimensional porous graphene framework.
[0026] Step 2: Dissolve 0.5 g of polystyrene and 2.5 g of phase change paraffin in 50 mL of toluene, stir to dissolve, and form a responsive phase change solution, wherein the melting point of the phase change paraffin is 25℃;
[0027] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Immerse at 40°C for 12 hours.
[0028] Step 4: The self-assembled composite material is first cooled from the solution clearing point temperature to 10℃ at a rate of 0.5℃ / min, kept at that temperature for 1 h, and then cooled to room temperature at a rate of 5℃ / min.
[0029] Step 5: Remove the cured material, centrifuge to remove residual solution from the surface, and obtain a new type of graded graphite material.
[0030] Example 2:
[0031] This embodiment describes a method for preparing a novel graded graphite material, comprising the following steps:
[0032] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network was grown on copper foam with a pore size of 500 μm using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the metal template was removed with 2 mol / L ferric chloride solution in an 80℃ water bath to obtain a three-dimensional porous graphene framework.
[0033] Step 2: Dissolve 0.5 g of polymethyl methacrylate and 10 g of phase change paraffin in 50 mL of toluene, stir to dissolve, and form a responsive phase change solution, wherein the melting point of the phase change paraffin is 60℃;
[0034] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Immerse at 70°C for 2 hours.
[0035] Step 4: The self-assembled composite material is first cooled from the solution clearing point temperature to 5°C at a rate of 1°C / min, kept at that temperature for 4 h, and then cooled to room temperature at a rate of 2°C / min.
[0036] Step 5: Remove the cured material, centrifuge to remove residual solution from the surface, and obtain a new type of graded graphite material.
[0037] Example 3:
[0038] This embodiment describes a method for preparing a novel graded graphite material, comprising the following steps:
[0039] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network was grown on copper foam with a pore size of 300 μm using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the metal template was removed with 2 mol / L hydrochloric acid solution in a 60℃ water bath to obtain a three-dimensional porous graphene framework.
[0040] Step 2: Dissolve 0.5 g of polystyrene and 6.25 g of phase change paraffin in 50 mL of toluene, stir to dissolve, and form a responsive phase change solution, wherein the melting point of the phase change paraffin is 42.5℃;
[0041] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Immerse at 55°C for 7 hours.
[0042] Step 4: First, the self-assembled composite material is cooled from the solution clearing point temperature to 5℃ at a rate of 0.5℃ / min and kept at that temperature for 2.5 h, and then cooled to room temperature at a rate of 5℃ / min.
[0043] Step 5: Remove the cured material, centrifuge to remove residual solution from the surface, and obtain a new type of graded graphite material.
[0044] Example 4:
[0045] This embodiment describes a method for preparing a novel graded graphite material, comprising the following steps:
[0046] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network was grown on nickel foam with a pore size of 100 μm using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the metal template was removed with 2 mol / L ferric chloride solution in an 80℃ water bath to obtain a three-dimensional porous graphene framework.
[0047] Step 2: Dissolve 0.5 g of polymethyl methacrylate and 2.5 g of phase change paraffin in 50 mL of toluene, stir to dissolve, and form a responsive phase change solution, wherein the melting point of the phase change paraffin is 60℃;
[0048] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Immerse at 70°C for 12 hours.
[0049] Step 4: First, the self-assembled composite material is cooled from the solution clearing point temperature to 10℃ at a rate of 1℃ / min, kept at that temperature for 1 h, and then cooled to room temperature at a rate of 2℃ / min.
[0050] Step 5: Remove the cured material, centrifuge to remove residual solution from the surface, and obtain a new type of graded graphite material.
[0051] Comparative Example 1: The difference between this comparative example and Example 1 is that it does not have a three-dimensional porous graphene framework, and the composite material is prepared by a simple physical blending method.
[0052] Step 1: Weigh 0.5 g of polystyrene and 2.5 g of phase change paraffin, heat them at 80°C to melt, and stir and mix for 30 min to obtain a blend;
[0053] Step 2: Press the blend into a sheet of the same size as the finished product in Example 1, cool it to room temperature, and obtain a sample.
[0054] Comparative Example 2: The difference between this comparative example and Example 1 is that rapid quenching is used instead of programmed cooling curing.
[0055] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network was grown on nickel foam with a pore size of 100 μm using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the metal template was removed with 2 mol / L hydrochloric acid solution in a 40℃ water bath to obtain a three-dimensional porous graphene framework.
[0056] Step 2: Dissolve 0.5 g of polystyrene and 2.5 g of phase change paraffin in 50 mL of toluene, stir to dissolve, and form a responsive phase change solution, wherein the melting point of the phase change paraffin is 60℃;
[0057] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Immerse at 40°C for 12 hours.
[0058] Step 4: Quickly immerse the self-assembled composite material in an ice-water mixture to quench it and allow it to solidify instantly;
[0059] Step 5: Remove the cured material, centrifuge to remove residual solution from the surface, and obtain the new graphite material.
[0060] Comparative Example 3: The difference between this comparative example and Example 1 is that epoxy resin is used instead of polystyrene.
[0061] Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network was grown on nickel foam with a pore size of 100 μm using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the metal template was removed with 2 mol / L hydrochloric acid solution in a 40℃ water bath to obtain a three-dimensional porous graphene framework.
[0062] Step 2: Dissolve 0.5 g of epoxy resin and 2.5 g of phase change paraffin in 50 mL of toluene, stir to dissolve, and form a responsive phase change solution, wherein the melting point of the phase change paraffin is 42.5℃;
[0063] Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Immerse at 40°C for 12 hours.
[0064] Step 4: The self-assembled composite material is first cooled from the solution clearing point temperature to 10℃ at a rate of 0.5℃ / min, kept at that temperature for 1 h, and then cooled to room temperature at a rate of 5℃ / min.
[0065] Step 5: Remove the cured material, centrifuge to remove residual solution from the surface, and obtain a new type of graded graphite material.
[0066] Performance testing
[0067] 1 Thermal conductivity
[0068] The thermal conductivity of the samples was tested according to GB / T 10295-2008 standard. A higher thermal conductivity coefficient indicates better thermal conductivity. The formula for calculating the thermal conductivity coefficient is λ = (Q × d) / (A × ΔT), where λ is the thermal conductivity coefficient (W·m⁻¹·K⁻¹), Q is the heat flow rate (W), d is the thickness of the test sample (m), and A is the area of the heat flow meter (m²). 2 ΔT is the temperature difference between the hot and cold surfaces of the sample, in K. The thermal conductivity test results are shown in Table 1.
[0069] Table 1 Thermal conductivity test data
[0070] sample Thermal conductivity (W·m⁻¹·K⁻¹) Example 1 12.5 Example 2 11.8 Example 3 13.2 Example 4 10.9 Comparative Example 1 2.1 Comparative Example 2 8.4 Comparative Example 3 7.6
[0071] As shown in Table 1, the novel graphite materials prepared in Examples 1-4, due to their three-dimensional graphene framework and programmed cooling curing, have a thermal conductivity of no less than 10.9 W·m. -1 ·K -1 The first example has good thermal conductivity. However, Comparative Example 1 lacks a three-dimensional graphene structure and has poor thermal conductivity. The rapid quenching in Comparative Example 2 resulted in an uneven material structure and decreased thermal conductivity. Comparative Example 3 used epoxy resin instead of polystyrene, which had poor compatibility and affected the heat conduction path.
[0072] 2 Thermal response performance
[0073] The thermal response performance of the novel graphite materials was tested according to the GB / T 32064-2015 standard. The greater the maximum heating rate, the faster the thermal response performance of the material. The test results of the thermal response performance are shown in Table 2.
[0074] Table 2 Thermal Response Performance Test Data
[0075] sample Maximum heating rate (°C / s) Characteristic response time t90 (s) Example 1 0.45 117 Example 2 0.46 118 Example 3 0.48 105 Example 4 0.40 125 Comparative Example 1 0.12 380 Comparative Example 2 0.31 154 Comparative Example 3 0.23 199
[0076] As shown in Table 2, Examples 1-4 exhibited a maximum heating rate greater than 0.40℃ / s and a characteristic response time t90 between 105-125 s, demonstrating good thermal response performance. This is because the three-dimensional interconnected graphene framework constructed through chemical vapor deposition effectively acts as a heat conduction channel when heat is input from the outside, rapidly transferring heat to all parts of the material with extremely low resistance, thus enabling the material to heat up quickly. In contrast, Comparative Examples 1-3 had a characteristic response time as long as 380 s and a maximum heating rate as low as 0.12℃ / s. Comparative Example 1, in particular, lacked an efficient heat transfer channel, preventing rapid heat diffusion within the material and resulting in poor thermal response performance.
[0077] 3 Thermal Cycling Stability
[0078] The thermal cycling stability of the samples was tested according to ASTM D3418 standard. 1000 heating-cooling cycles were performed within the phase change temperature range, and the thermal conductivity was observed. The test results of the thermal cycling stability are shown in Table 3.
[0079] Table 3 Thermal Cycling Stability Test Data
[0080] sample Thermal cycling stability (thermal conductivity retention rate after 1000 cycles / %) Example 1 98 Example 2 97 Example 3 99 Example 4 96 Comparative Example 1 72 Comparative Example 2 85 Comparative Example 3 84
[0081] As shown in Table 3, compared with the comparative examples, the materials prepared in Examples 1-4 maintained a thermal conductivity retention rate of over 96% after 1000 thermal cycles, demonstrating excellent thermal cycling performance. This is mainly because the three-dimensional graphene framework maintained the integrity of the overall structure during the repeated melting and solidification of the phase change material; the vacuum immersion and molecular self-assembly processes greatly suppressed the flow and migration of the phase change material in the liquid state; and the thermoplastic polymer polystyrene, as a flexible interface layer, not only enhanced the compatibility between graphene and paraffin but also buffered the micro-stress generated during the phase change process, ensuring structural reliability under long-term cycling. The thermal cycling stability of Comparative Examples 1-3 was lower than that of all the examples, demonstrating the important role of the synergistic structure of the "three-dimensional graphene framework-polymer-phase change paraffin" in maintaining the high efficiency and stability of novel graphite materials.
[0082] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing a novel graded graphite material, characterized in that, Includes the following steps: Step 1: Under high temperature conditions of 1000℃, a three-dimensional interconnected graphene network is grown on a foam metal template using methane as the carbon source and hydrogen as the reducing and regulating gas. Then, the foam metal template is removed with an etching solution to obtain a three-dimensional porous graphene framework. Step 2: Dissolve the thermoplastic polymer and phase change paraffin in toluene, stir to dissolve, and form a responsive phase change solution; Step 3: Place the three-dimensional graphene framework in a vacuum container, add the responsive phase change solution, and ensure that the solution completely submerges the framework. The phase change material molecules self-assemble on the graphene surface. Step 4: Perform programmed cooling and curing on the self-assembled composite material; Step 5: Remove the cured material and remove any residual solution from the surface to obtain a new type of graded graphite material.
2. The method for preparing a novel graded graphite material according to claim 1, characterized in that, In step 1, the pore size of the foam metal template is 100-500 μm, and the foam metal template is either foam nickel or foam copper.
3. The method for preparing a novel graded graphite material according to claim 1, characterized in that, In step 1, the corrosive solution is either hydrochloric acid solution or ferric chloride solution.
4. The method for preparing a novel graded graphite material according to claim 1, characterized in that, In step 1, the temperature at which the etchant removes the metal template is a 40-80℃ water bath.
5. The method for preparing a novel graded graphite material according to claim 1, characterized in that, In step 2, the thermoplastic polymer is polystyrene or polymethyl methacrylate.
6. The method for preparing a novel graded graphite material according to claim 1, characterized in that, In step 2, the mass ratio of thermoplastic polymer to phase change paraffin is 1:(5-20).
7. The method for preparing a novel graded graphite material according to claim 6, characterized in that, The melting point of the phase change paraffin in step 2 is 25-60℃.
8. The method for preparing a novel graded graphite material according to claim 1, characterized in that, In step 3, the self-assembly temperature is 40-70℃ and the time is 2-12 h.
9. The method for preparing a novel graded graphite material according to claim 1, characterized in that, The cooling and curing method in step 4 is as follows: first, the temperature is lowered from the solution clearing point temperature to 5-10℃ at a rate of 0.5-1℃ / min, and kept at that temperature for 1-4 hours, and then the temperature is lowered to room temperature at a rate of 2-5℃ / min.
10. A novel graded graphite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.