A method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials

Abstract

The present invention discloses a method for preparing an integrated carbon nanotube / bamboo fungus skeleton for improving the thermal conductivity of a solid-liquid phase change material. The method comprises the following steps: (1) carbon nanotube dispersion treatment, (2) carbon nanotube adhesion treatment on the bamboo fungus surface, (3) co-carbonization treatment, and (4) composite phase change material treatment. The method prepares an integrated skeleton composed of a bamboo fungus porous structure and carbon nanotubes through a simple co-carbonization treatment, thereby solving the problems of carbon nanotube aggregation and accumulation, as well as secondary aggregation and accumulation during application. The method also provides a stable heat transfer link and a larger effective heat exchange area, making it easy to improve the thermal conductivity of the solid-liquid phase change material. In addition, the method has common materials, a simple process, no pollution risks, and has the potential for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the field of phase change heat storage technology, relates to the enhancement of the thermal conductivity of phase change materials, and particularly relates to a method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials. Background Art

[0002] Solid-liquid phase change materials (hereinafter referred to as "phase change materials") as a carrier for thermal energy storage are a vital part of phase change heat storage technology. Phase change materials absorb / release a large amount of heat during the phase change process, and have a large heat storage density within a small temperature change range. They are expected to achieve large-scale engineering applications both technically and economically. However, the phase change materials used in heat storage technology, such as paraffin wax and molten salt, have low thermal conductivity, which greatly limits the charging / discharging rate of the heat storage system during operation and affects the heat storage efficiency of the heat storage system. To solve the above problems, it is necessary to improve the thermal conductivity of the phase change material so that the phase change material can adapt to the needs of actual heat storage applications.

[0003] Currently, the methods that are widely used and effective in improving the thermal conductivity of phase change materials are: (1) adding thermal conductive fillers to the phase change material and (2) introducing a thermal conductive skeleton. Method (1) utilizes the high thermal conductivity and geometric morphology of the thermal conductive filler to construct a thermal conductive link inside the phase change material to improve the thermal conductivity of the phase change material. It has the advantages of simple preparation process and low preparation cost. The existing technology adds a series of nanomaterials such as carbon nanotubes, graphene, silicon carbide, boron nitride, etc. as thermal conductive fillers into the phase change material. However, due to the micro-nanoscale characteristics of most nanomaterials, the van der Waals force between the nanomaterials will cause the nanomaterials to attract each other and agglomerate and accumulate, resulting in uneven distribution of the nanomaterials in the phase change material, local aggregation or loss, thereby affecting the formation of the thermal conductive link. Method (2) prefabricates a porous skeleton with fixed heat-conducting links by physical or chemical methods and impregnates it into the interior of the phase change material to improve the thermal conductivity of the phase change material. Although it overcomes the agglomeration and accumulation problems existing in method (1), the process of prefabricating the skeleton usually includes more complicated process steps or involves complex chemical reaction processes, and the preparation quantity is limited. The above problems limit the large-scale application of the thermal conductive skeleton.

[0004] In addition, to address the agglomeration and accumulation problems of nanomaterials, current technologies typically use dispersants, mechanical grinding, high-speed shearing and other dispersion methods to disperse nanomaterials. However, the above methods cannot maintain the dispersed morphology of the dispersed nanomaterials for a long time. Especially when nanomaterials are combined with phase change materials, the surface tension of the molten liquid phase change material easily causes the nanomaterials to re-aggregate. This phenomenon of secondary agglomeration and accumulation of nanomaterials is also one of the factors that restrict the application and promotion of nanomaterials as thermal conductive fillers. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials. This method prepares an integrated skeleton composed of carbon nanotubes carried on a porous structure of bamboo fungus through a simple co-carbonization method, solving the problems of agglomeration and accumulation of the carbon nanotubes themselves and the secondary agglomeration and accumulation problems that exist during application. In addition, the material selection is common, the process is simple, and it has the potential for large-scale production.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of a solid-liquid phase change material comprises the following steps:

[0008] Step 1: Dispersing carbon nanotubes in an agglomerated and stacked state and maintaining the dispersed morphology of the carbon nanotubes;

[0009] Step 2: Using bamboo fungus as a skeleton, temporarily adhering dispersed carbon nanotubes to the surface of bamboo fungus and maintaining the dispersed state to obtain a carbon nanotube / bamboo fungus impregnation precursor;

[0010] Step 3: The carbon nanotube / bamboo fungus is impregnated with a precursor and carbonized. After carbonization, the cellulose and organic matter contained in the bamboo fungus are converted into carbon and combined with the carbon nanotubes adhered to the surface, thereby fixing the carbon nanotubes and forming a shape-stable carbon nanotube / bamboo fungus integrated skeleton.

[0011] Step 4: Compounding the carbon nanotube / bamboo fungus integrated skeleton with a solid-liquid phase change material to improve the thermal conductivity of the solid-liquid phase change material.

[0012] In one embodiment, the step 1 of dispersing the carbon nanotubes in the agglomerated and stacked state and maintaining the dispersed morphology of the carbon nanotubes is achieved as follows:

[0013] The carbon nanotubes and the ethanol solution are uniformly mixed and ultrasonically dispersed for later use. Glycerol is heated at 30-60° C. and uniformly mixed with the carbon nanotube-ethanol mixed solution after ultrasonic dispersion. After mixing, the mixture is continuously heated and stirred at 30-60° C. until the residual ethanol in the mixed solution is completely volatilized, thereby obtaining a carbon nanotube-glycerol mixed solution in which the carbon nanotubes are dispersed.

[0014] In one embodiment, the step 2, using bamboo fungus as a skeleton, temporarily adhering dispersed carbon nanotubes to the surface of the bamboo fungus and maintaining the dispersed state, is implemented as follows:

[0015] The bamboo fungus is immersed in the carbon nanotube and glycerol mixture to ensure that all pores of the bamboo fungus are filled with carbon nanotubes. After complete immersion, the bamboo fungus is taken out and placed in a vacuum drying oven at 30-80° C. for drying until no liquid drops fall within 10-30 seconds when the immersed bamboo fungus is suspended in the air, thereby obtaining a carbon nanotube / bamboo fungus impregnated precursor.

[0016] In one embodiment, the method of ensuring that all pores of the bamboo fungus are filled with carbon nanotubes is as follows:

[0017] The viscosity of the prepared carbon nanotube and glycerol mixture is lower than 300 mPa·s. The impregnation container is placed in a vacuum drying oven under vacuum drying conditions of 30-60° C. for 1-5 hours.

[0018] In one embodiment, the step 3 of carbonizing the carbon nanotube / bamboo fungus impregnated precursor is carried out as follows:

[0019] The dried carbon nanotube / bamboo fungus impregnated precursor is placed in a tubular furnace for heating and carbonization treatment. The carbonization conditions are uniformly heating from 20-40°C to 500-800°C at a heating rate of 0.5-1.5°C / min, and finally keeping at 500-800°C for 1-3 hours, and naturally cooling to room temperature to obtain a carbon nanotube / bamboo fungus integrated skeleton.

[0020] In one embodiment, the step 4 is to compound the carbon nanotube / bamboo fungus integrated skeleton with the phase change material to improve the thermal conductivity of the phase change material, and the implementation method is as follows:

[0021] The carbon nanotube / bamboo fungus integrated skeleton is composited with a solid-liquid phase change material, with the solid-liquid phase change material serving as a matrix and the carbon nanotube / bamboo fungus integrated skeleton serving as an internal reinforcement of the matrix. The composite is placed together in a vacuum drying oven, and the vacuum drying conditions are 100-300° C. for 1-5 hours to obtain a composite solid-liquid phase change material with enhanced thermal conductivity.

[0022] In one embodiment, the carbon nanotubes are replaced by one or more of graphene, boron nitride, silicon nitride, gallium nitride, silicon carbide, ferroferric oxide, ferric oxide, zinc oxide and copper oxide, and the particle size of the material is 10 -2 -10 4 μm.

[0023] In one embodiment, the bamboo fungus is made into a spherical, ellipsoidal, cylindrical, truncated cone, rectangular parallelepiped, cube or tetrahedron shape according to the actual shape of the phase change heat storage unit in the heat storage device to facilitate compounding with the solid-liquid phase change material.

[0024] In one embodiment, the solid-liquid phase change material includes organic and inorganic materials. The organic materials include paraffin, fatty acid, polyol, and lipid. The inorganic materials include molten salt, crystalline hydrated salt, and metal.

[0025] In one embodiment, the glycerol may be replaced with flour paste and / or syrup.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention not only overcomes the agglomeration of carbon nanotubes but also effectively avoids the secondary agglomeration problem existing in the prior art by stably and evenly dispersing carbon nanotubes on the pore walls of bamboo fungus and then compounding them with solid-liquid phase change materials. This provides a new way to apply carbon nanotubes in improving the thermal conductivity of phase change materials.

[0028] 2. The present invention prepares an integrated skeleton composed of a porous structure of bamboo fungus and carbon nanotubes through a simple co-carbonization method, while providing a stable heat conduction link and a larger effective heat exchange area, which easily improves the thermal conductivity of the solid-liquid phase change material. In addition, this method has common materials, a simple process, and no pollution risks, and has the potential for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Flowchart of the method for preparing the carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of the solid-liquid phase change material of the present invention

[0030] Figure 2 This is a comparison chart of thermal conductivity of paraffin-based composite phase change materials.

[0031] Figure 3 This is a scanning electron microscope image of the carbonized bamboo fungus surface without carbon nanotubes.

[0032] Figure 4 This is a scanning electron microscope image of the carbon nanotube / bamboo fungus integrated skeleton. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the purpose, method and advantages of the present invention, the present invention is further described with reference to the accompanying drawings.

[0034] like Figure 1 As shown, the present invention is a method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials, which mainly includes the following steps:

[0035] Step (1), carbon nanotube dispersion treatment.

[0036] Under normal conditions, carbon nanotubes are often in a state of agglomeration and accumulation. In this step, the main purpose is to disperse the carbon nanotubes in a state of agglomeration and accumulation and maintain the dispersed form of the carbon nanotubes, with the aim of solving the agglomeration and accumulation problems of the carbon nanotubes themselves. Specifically, the carbon nanotubes are first mixed evenly with the ethanol solution, and then ultrasonic dispersion treatment is performed for about 30 minutes. Then, glycerol is heated to 30-60°C and evenly mixed with the carbon nanotube-ethanol mixture after ultrasonic dispersion treatment. Finally, the mixed material is heated and stirred again at 30-60°C until the residual ethanol in the mixture is completely evaporated. At this time, a mixture of carbon nanotubes and glycerol is obtained, and the carbon nanotubes in the mixture are in a dispersed state. For example, the temperature of both heatings can be further selected to be 40°C.

[0037] In this step, the carbon nanotubes are dispersed in glycerol with the aid of an ethanol solution through ultrasonic dispersion and heating stirring, which has a better dispersion effect. The glycerol can maintain the dispersed form of the carbon nanotubes and provide some carbon. The ethanol in the product is completely volatilized and does not affect the subsequent steps.

[0038] Step (2), carbon nanotube adhesion treatment on the surface of bamboo fungus.

[0039] In this step, with bamboo fungus as skeleton, by the large specific surface area of ​​bamboo fungus, the carbon nanotube of the dispersed state obtained by step (1) is temporarily adhered to the bamboo fungus surface, and maintain dispersed state, obtain carbon nanotube / bamboo fungus impregnation precursor, object is to facilitate subsequent carbonization finalization, solve carbon nanotube secondary agglomeration and accumulation problem. Specifically, bamboo fungus is impregnated in the carbon nanotube obtained by step (1) and glycerol mixed solution, and as far as possible ensure that all pores of bamboo fungus are filled with carbon nanotubes, take out after complete impregnation, put into vacuum drying oven and dry under 30-80 DEG C of conditions, until the bamboo fungus after impregnation is suspended and placed in the time of 10-30s without liquid dripping, illustrate that drying is complete, obtain carbon nanotube / bamboo fungus impregnation precursor, illustratively, can further be selected as no liquid dripping in the time of 15s.

[0040] Furthermore, to ensure that all pores of the bamboo fungus are filled with carbon nanotubes, the viscosity of the carbon nanotube and glycerol mixture prepared in step (1) of the present invention is recommended to be less than 300 mPa·s. Furthermore, after impregnation, the impregnation container can be directly placed in a vacuum drying oven and vacuum dried at 30-60°C for about 1-5 hours, which generally completes the drying process. For example, the drying temperature can be selected to be 30°C.

[0041] In this step, bamboo fungus is selected as the skeleton. In addition to utilizing its large specific surface area, the more important reason is that bamboo fungus contains crude fiber, organic matter and a small amount of protein, which are beneficial to maintaining the morphology of bamboo fungus and providing a part of carbon source during the later carbonization process.

[0042] Step (3), co-carbonization treatment.

[0043] In this step, the carbon nanotube / bamboo fungus impregnated precursor obtained in step (2) is carbonized to convert the cellulose and organic matter contained in the bamboo fungus into carbon, and the carbon nanotubes are combined with the carbon nanotubes adhered to the surface thereof, thereby fixing the carbon nanotubes to form a shape-stable carbon nanotube / bamboo fungus integrated skeleton. Specifically, this step can be performed by heating and carbonizing in a tubular furnace. The carbon nanotube / bamboo fungus impregnated precursor after drying in step (2) is placed in the tubular furnace. The carbonization conditions are designed to be uniformly heated from 20-40° C. to 500-800° C. at a heating rate of 0.5-1.5° C. / min, and finally kept at 500-800° C. for 1-3 hours, and then naturally cooled to room temperature. The carbonization conditions are determined by the shape and size of the carbon nanotube / bamboo fungus impregnated precursor to obtain a carbon nanotube / bamboo fungus integrated skeleton.

[0044] Carbonization conditions are an important part of ensuring the stability of the shape of the carbon nanotube / bamboo fungus integrated skeleton. Under the heating conditions of the present invention, the crude fibers, organic matter and a small amount of protein in the bamboo fungus can complete the carbonization process. Under the heat preservation conditions of the present invention, the degree of graphitization of the bamboo fungus can be improved.

[0045] In this step, an integrated skeleton composed of a porous structure of bamboo fungus and carbon nanotubes is prepared by co-carbonization, which not only provides a stable heat conduction link, but also has a larger heat exchange area, which is conducive to compounding with solid-liquid phase change materials to improve their thermal conductivity.

[0046] Step (4), composite phase change material processing.

[0047] This step utilizes the carbon nanotube / bamboo fungus integrated skeleton obtained in step (3) to composite with a solid-liquid phase change material, thereby utilizing the carbonaceous heat conduction link and large specific surface area of ​​the carbon nanotube / bamboo fungus integrated skeleton to enhance the thermal conductivity of the solid-liquid phase change material. Specifically, the solid-liquid phase change material is used as a matrix, and the carbon nanotube / bamboo fungus integrated skeleton is used as an internal reinforcement of the matrix. The two are placed together in a vacuum drying oven and vacuum dried at 100-300°C for 1-5 hours to obtain a composite solid-liquid phase change material with enhanced thermal conductivity.

[0048] The vacuum drying conditions in this step are determined by the type of solid-liquid phase change material. Under these vacuum drying conditions, the solid-liquid phase change material can complete the melting process and fully fill the pores of the carbon nanotube / bamboo fungus integrated skeleton.

[0049] The present invention uniformly disperses the carbon nanotubes in the pores of the bamboo fungus and then compounds them with the solid-liquid phase change material, thereby perfectly overcoming the problems of agglomeration and accumulation of the carbon nanotubes.

[0050] In more embodiments of the present invention, the carbon nanotubes can be replaced by one or more combinations of graphene, boron nitride, silicon nitride, gallium nitride, silicon carbide, ferroferric oxide, ferric oxide, zinc oxide and copper oxide, and the particle size of the material is ensured to be 10 -2 -10 4 μm. Graphene, boron nitride, silicon nitride, gallium nitride, silicon carbide, zinc oxide, and copper oxide are materials targeted for improving thermal conductivity due to their excellent thermal conductivity. Ferroferric oxide and ferric oxide have good magnetic loss effects and can be used to improve the electromagnetic shielding performance of materials.

[0051] In further embodiments of the present invention, the glycerol mentioned above can be replaced with flour paste and / or syrup to provide a partial carbon source for the carbonization process. In further embodiments of the present invention, the bamboo fungus can be made into a spherical, ellipsoidal, cylindrical, truncated cone, rectangular parallelepiped, cube or tetrahedron shape according to the actual shape of the phase change heat storage unit in the heat storage device to facilitate compounding with the solid-liquid phase change material.

[0052] In more embodiments of the present invention, the solid-liquid phase change material includes organic and inorganic materials. The organic materials include paraffin, fatty acids, polyols, and lipids, and the inorganic materials include molten salts, crystalline hydrated salts, and metals.

[0053] Reference again Figure 1 , according to the process shown in the figure, the preparation of paraffin-based composite phase change material with enhanced thermal conductivity is completed. The specific process is as follows:

[0054] Step (1): uniformly mix the carbon nanotubes with 75% ethanol solution and perform ultrasonic dispersion treatment for 30 minutes;

[0055] Step (2): heating glycerol at 40° C. and uniformly mixing it with the carbon nanotube-ethanol mixed solution after ultrasonic dispersion treatment in step (1); and continuously heating and stirring at 40° C. until the residual ethanol in the mixed solution is completely volatilized, thereby obtaining a carbon nanotube-glycerol mixed solution;

[0056] Step (3): The bamboo fungus is cut and separated along the axial direction and cut into squares of 5×5 cm in length and width respectively, with 5 pieces overlapping in the height direction, and the total height is 1 cm. The bamboo fungus after treatment is immersed in the mixed solution of carbon nanotubes and glycerol described in step (2) to ensure that all pores of the bamboo fungus are filled with carbon nanotubes. After complete immersion, the bamboo fungus is taken out and placed in a vacuum drying oven at 30° C. for 2 hours, and dried to the extent that no liquid drops fall within 15 seconds when the immersed bamboo fungus is placed in the air;

[0057] Step (4): placing the dried carbon nanotube / bamboo fungus impregnated precursor in step (3) into a tube furnace for heating and carbonization treatment. The carbonization conditions are: uniformly heating from 30°C to 600°C at a heating rate of 0.5°C / min, and finally keeping at 600°C for 1 hour, cooling naturally to room temperature, and then taking out;

[0058] Step (5): The carbon nanotubes / bamboo fungus after carbonization in step (4) are placed in ethanol and ultrasonically cleaned for 30 minutes to remove the carbon nanotubes not bound to the bamboo fungus. After ultrasonic cleaning, the carbon nanotubes / bamboo fungus are dried at 40° C. until the ethanol is completely volatilized, thereby completing the preparation of the carbon nanotube / bamboo fungus integrated skeleton.

[0059] Step (6): Compounding the carbon nanotube / bamboo fungus integrated skeleton described in step (5) with paraffin, wherein the paraffin is docosane, and the phase change temperature is 50°C. The paraffin serves as the matrix, and the carbon nanotube / bamboo fungus integrated skeleton serves as the internal reinforcement of the matrix. The two are placed together in a vacuum drying oven and taken out after being dried at 100°C for 2 hours to obtain a paraffin-based composite phase change material with enhanced thermal conductivity.

[0060] Using the same carbon nanotubes and paraffin wax, the carbon nanotubes are ground and dispersed according to the existing grinding and dispersion technology, and then the ground and dispersed carbon nanotubes and paraffin wax are mixed, and the same vacuum drying treatment as step (6) is performed to obtain a paraffin-based composite phase change material with only carbon nanotubes added.

[0061] By controlling the content of carbon nanotubes, a series of paraffin-based composite phase change materials with carbon nanotube volume contents of 5%, 10%, 15%, 20%, 25% and 30% were prepared for the above two types of paraffin-based composite phase change materials (adding carbon nanotube / bamboo fungus integrated skeleton and adding only carbon nanotubes).

[0062] The thermal conductivity of the above two types of paraffin-based composite phase change materials and pure paraffin was measured using a thermal conductivity tester. The results are as follows: Figure 2 As shown, it is obvious that the thermal conductivity of the paraffin-based composite phase change material containing a carbon nanotube / bamboo fungus integrated skeleton is higher than that of the group containing only carbon nanotubes and pure paraffin.

[0063] Figure 3 This is a scanning electron microscope image of the surface of carbonized bamboo fungus without carbon nanotubes. Obviously, although the bamboo fungus has undergone carbonization treatment, its pore shape is still well maintained. Figure 4 This is a scanning electron microscope image of the carbon nanotube / bamboo fungus integrated skeleton. From the image, it can be observed that the carbon nanotubes are relatively evenly attached to the pore surface of the bamboo fungus.

[0064] In summary, this invention provides an effective new method for enhancing the thermal conductivity of solid-liquid phase change materials. The composite solid-liquid phase change material can be used as a heat storage module for heat storage and heat exchange equipment. Due to its manufacturability, it can be flexibly arranged in series as heat storage units within a heat storage system, making it suitable for large-scale heat storage systems.

[0065] Although the above content has described the embodiments of the present invention, those skilled in the art may still make changes and modifications based on the inventive concept of the present invention. Therefore, the content of this specification is only one embodiment of the present invention and does not limit the scope of protection of the patent of the present invention. Any equivalent transformation made using the content of the present invention, or directly or indirectly applied in other related technical fields, is included in the scope of protection of the present invention and should not be construed as limiting the present invention.

Claims

1. A method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials, characterized in that: The steps include: Step 1: Dispersing carbon nanotubes in an agglomerated and stacked state and maintaining the dispersed morphology of the carbon nanotubes; Step 2: Using bamboo fungus as a skeleton, temporarily adhere dispersed carbon nanotubes to the surface of bamboo fungus and maintain the dispersed state to obtain a carbon nanotube / bamboo fungus impregnation precursor. The implementation method is as follows: The bamboo fungus is immersed in the carbon nanotube and glycerol mixture, wherein the viscosity of the carbon nanotube and glycerol mixture is less than 300 mPa·s to ensure that all pores of the bamboo fungus are filled with carbon nanotubes. After complete immersion, the bamboo fungus is taken out and the immersion container is placed in a vacuum drying oven under vacuum drying conditions of 30-60° C. for 1-5 hours, and dried to the extent that no liquid drops fall within 10-30 seconds when the immersed bamboo fungus is placed in the air, thereby obtaining a carbon nanotube / bamboo fungus impregnated precursor; Step 3: Carbonizing the carbon nanotube / bamboo fungus impregnated precursor. After carbonization, the cellulose and organic matter contained in the bamboo fungus are converted into carbon, which combines with the carbon nanotubes adhered to the surface, thereby fixing the carbon nanotubes and forming a shape-stable carbon nanotube / bamboo fungus integrated skeleton. Step 4: Compounding the carbon nanotube / bamboo fungus integrated skeleton with a solid-liquid phase change material to improve the thermal conductivity of the solid-liquid phase change material.

2. The method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: The step 1 is to disperse the carbon nanotubes in the agglomerated and accumulated state and maintain the dispersed form of the carbon nanotubes, and the implementation method is as follows: The carbon nanotubes and the ethanol solution are uniformly mixed and ultrasonically dispersed for later use. Glycerol is heated at 30-60° C. and uniformly mixed with the carbon nanotube-ethanol mixed solution after ultrasonic dispersion. After mixing, the mixture is continuously heated and stirred at 30-60° C. until the residual ethanol in the mixed solution is completely volatilized, thereby obtaining a carbon nanotube-glycerol mixed solution in which the carbon nanotubes are dispersed.

3. The method for preparing a carbon nanotube / bamboo fungus integrated framework for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: The step 3, carbonizing the carbon nanotube / bamboo fungus impregnated precursor, is implemented as follows: The dried carbon nanotube / bamboo fungus impregnated precursor is placed in a tubular furnace for heating and carbonization treatment. The carbonization conditions are uniformly heating from 20-40°C to 500-800°C at a heating rate of 0.5-1.5°C / min, and finally keeping at 500-800°C for 1-3 hours, and naturally cooling to room temperature to obtain a carbon nanotube / bamboo fungus integrated skeleton.

4. The method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: The step 4 is to compound the carbon nanotube / bamboo fungus integrated skeleton with the phase change material to improve the thermal conductivity of the phase change material. The implementation method is as follows: The carbon nanotube / bamboo fungus integrated skeleton is composited with a solid-liquid phase change material, with the solid-liquid phase change material serving as a matrix and the carbon nanotube / bamboo fungus integrated skeleton serving as an internal reinforcement of the matrix. The composite is placed together in a vacuum drying oven, and the vacuum drying conditions are 100-300° C. for 1-5 hours to obtain a composite solid-liquid phase change material with enhanced thermal conductivity.

5. The method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: The carbon nanotubes are replaced by one or more of graphene, boron nitride, silicon nitride, gallium nitride, silicon carbide, ferroferric oxide, ferric oxide, zinc oxide and copper oxide, and the particle size of the material is 10 -2 -10 4 µm.

6. The method for preparing a carbon nanotube / bamboo fungus integrated skeleton for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: According to the actual shape of the phase change heat storage unit in the heat storage device, the bamboo fungus is made into a spherical, ellipsoidal, cylindrical, truncated cone, rectangular parallelepiped, cube or tetrahedron shape to facilitate compounding with the solid-liquid phase change material.

7. The method for preparing a carbon nanotube / bamboo fungus integrated framework for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: The solid-liquid phase change materials include organic and inorganic types. The organic types include paraffin, fatty acid, polyol, lipid, and the inorganic types include molten salt, crystalline hydrated salt, and metal.

8. The method for preparing a carbon nanotube / bamboo fungus integrated framework for improving the thermal conductivity of solid-liquid phase change materials according to claim 1, characterized in that: The glycerol is replaced with a flour paste and / or syrup.

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