Energy storage and heat dissipation function integrated three-layer sandwich graphene porous polymer hollow microsphere and preparation method thereof

Abstract

The invention provides energy storage and heat dissipation function integrated three-layer sandwich graphene porous polymer hollow microspheres and a preparation method thereof.The method comprises the steps that S1, SiO2, alkynyl monomers, halogen monomers and a catalyst are dispersed in a polymerization reaction solution for in-situ crosslinking, and porous polymer loaded SiO2 is prepared; step S2, adding the porous polymer loaded SiO2 obtained in the step S1 into template removal liquid, and preparing porous polymer hollow microspheres through etching treatment; s3, compounding graphene and a dispersion medium with the porous polymer hollow microspheres obtained in the step S2, separating and drying to prepare a graphene-coated porous polymer; and S4, mixing the graphene-coated porous polymer obtained in the step S3 with a heat conducting agent, and carrying out induced phase change to prepare the three-layer sandwich graphene porous polymer hollow microspheres. The prepared thermal management material has a three-layer sandwich structure, high specific surface area, excellent thermal conductivity and ultralow thermal resistance, and can be widely applied to the fields of new energy, data centers, buildings and the like.

Description

Technical Field

[0001] The present invention relates to the technical fields of building heating modules, thermal interface of electronic devices, and high-efficiency thermal management materials for new energy heat storage systems, and particularly relates to a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions and a preparation method thereof. Background Art

[0002] With the rapid development of modern technology, the application requirements of materials science in the fields of architecture, electronics, energy, etc. are becoming increasingly complex and diverse. In the field of architecture, the intensification of the global energy crisis and the improvement of environmental awareness have led to a continuous increase in the demand for high-efficiency energy storage and heat storage materials. Although traditional energy storage and heat storage materials such as polystyrene foam and rock wool have excellent heat insulation performance, they have significant limitations in heat dissipation and are difficult to meet the requirements of modern buildings for dynamic thermal management. In the field of electronics, the miniaturization and high performance of electronic devices have made the heat dissipation problem a key bottleneck restricting their development. Although traditional heat dissipation materials such as metals and ceramics have good thermal conductivity, they have poor heat preservation performance and large density, which limits their application in lightweight design. At the same time, there are problems such as high cost and difficult processing. In the energy field, efficient thermal management materials are crucial for improving energy conversion efficiency and storage safety. Therefore, developing a multifunctional material that can simultaneously meet the requirements of energy storage and heat dissipation has become the key to solving the above problems.

[0003] Current research mainly attempts to solve the above contradictions through two paths: (1) Porous structure composite: By constructing multi-level pores (such as mesopore-macropore coupling) to reduce heat convection, such as silica aerogel [Adv. Mater. 2020, 32:1906258], but its mechanical properties are poor and it is easy to absorb moisture and fail; (2) Functionalization of thermal conductive fillers: Using materials such as carbon nanotubes and graphene to construct a thermal conductive network, but high filler loading will damage the continuity of the matrix, resulting in increased density and loss of flexibility [NanoEnergy 2021, 89: 106347]. In addition, there is an essential conflict between the physical mechanisms of energy storage and heat dissipation: Energy storage requires suppressing heat conduction, convection, and radiation, while heat dissipation requires establishing an efficient heat transport channel. Existing material designs mostly focus on the optimization of single functions and lack cross-scale structure regulation strategies. For example, although graphene / polymer composites can improve in-plane thermal conductivity through interfacial phonon coupling [ACS Nano 2022, 16: 10230], their thermal resistance is high and it is difficult to achieve effective thermal management. In addition, the surface modification techniques of porous materials (such as chemical vapor deposition, atomic layer deposition) have problems such as complex processes, high costs, and difficulty in scaling up, which limit their practical applications.

[0004] In the field of carbon materials, graphene, with its ultra-high thermal conductivity (3000 - 5000 W / (m·K)) and large specific surface area, has become a highly promising two-dimensional material that can be used to solve the above problems. It not only has excellent thermal conductivity but also good mechanical properties and chemical stability, thus having broad application prospects in the fields of heat conduction, heat dissipation, and energy storage. The high thermal conductivity of graphene enables rapid heat conduction, while its large specific surface area helps to improve the energy storage characteristics of the material. In addition, the excellent mechanical properties and chemical stability of graphene ensure its reliability in complex environments.

[0005] However, two-dimensional graphene sheets are prone to stacking and agglomeration due to van der Waals forces, resulting in a decrease in specific surface area and obstruction of the heat conduction path. To address this bottleneck, constructing a three-dimensional porous polymer hollow microsphere structure has become a breakthrough solution. The three-dimensional topological effect of this structure significantly increases the effective specific surface area, enhancing surface adsorption and interfacial heat exchange; its internal cavity can be directionally loaded with heat-conducting fillers to construct a three-dimensional interpenetrating heat conduction network, improving the heat dissipation efficiency. In addition, the porous polymer hollow microspheres can reduce the overall mass density and enhance the mechanical properties, meeting the high-strength requirements for heat-conducting materials in complex environments. Therefore, the design and development of multifunctional materials based on the porous polymer hollow microsphere structure provide new ideas for high-performance thermal management materials and show important application values in the fields of flexible electronic heat dissipation, phase change energy storage, etc. Summary of the Invention

[0006] The purpose of the present invention is to prepare a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions to meet the requirements for high-efficiency thermal management materials in new energy, data centers, and building systems.

[0007] To achieve the above purpose, the present invention provides a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions and its preparation method. The present invention disperses silicon dioxide (SiO2), alkyne monomers, halogen monomers, and a catalyst in a polymerization reaction solution for in-situ crosslinking to prepare porous polymer-loaded SiO2, adds the porous polymer-loaded SiO2 to a template removal solution to prepare porous polymer hollow microspheres, then composites and separates and dries them with graphene and a dispersion medium to prepare graphene-coated porous polymers, and finally mixes the graphene-coated porous polymers with a heat-conducting agent and raises the temperature to induce phase change to prepare three-layer sandwich graphene porous polymer hollow microspheres.

[0008] According to the first aspect of the present invention, a preparation method of a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions is provided, including the following steps: Step S1, preparing porous polymer loaded with SiO2: dispersing SiO2, an alkynyl monomer, a halogen monomer and a catalyst in a polymerization reaction solution for in-situ crosslinking to prepare porous polymer loaded with SiO2; Step S2, preparing porous polymer hollow microspheres: adding the porous polymer loaded with SiO2 obtained in Step S1 into a template removal solution and preparing porous polymer hollow microspheres through etching treatment; Step S3, preparing graphene-coated porous polymer: compounding, separating and drying the porous polymer hollow microspheres obtained in Step S2, graphene and a dispersion medium to prepare a graphene-coated porous polymer; Step S4, preparing a three-layer sandwich graphene porous polymer hollow microsphere: mixing the graphene-coated porous polymer obtained in Step S3 with a heat conduction agent and heating to induce phase change to prepare a three-layer sandwich graphene porous polymer hollow microsphere.

[0009] Preferably, in Step S1, the alkynyl monomer is one or more of p-phenylene diacetylene, m-phenylene diacetylene, 1,3,5-triethynylbenzene, 1,3,5-tris(bromoethynyl)benzene, tris(4-bromoethynylphenyl)amine, 1,6,8,13-tetraethynylpyrene, 1,2,4,5-tetrakis(bromoethynyl)benzene, and the halogen monomer is one or more of p-bromotoluene, m-chloroaniline, p-dibromobenzene, m-dibromobenzene, o-dibromobenzene, 1,4-dichlorobenzene, 1,4-diiodobenzene, 1,3,5-tribromobenzene; the molar ratio of the functional groups of the alkynyl monomer to the halogen monomer is 5:1 to 1:5.

[0010] Preferably, in Step S1, SiO2 is one or more of crystalline SiO2, amorphous SiO2, mesoporous SiO2, porous SiO2, gaseous SiO2, liquid SiO2, solid SiO2; the molar ratio of the sum of the alkynyl monomer and the halogen monomer to SiO2 is 1:5 to 1:15.

[0011] Preferably, in Step S1, the particle size of SiO2 is 50 nm to 10 μm, and the agglomeration size < 200 nm.

[0012] Preferably, in Step S1, the catalyst is a mixture of a palladium-based catalyst and a copper-based catalyst, and the molar ratio of the palladium-based catalyst to the copper-based catalyst is 5:1 to 1:20; the palladium-based catalyst is one or more of tetrakis(triphenylphosphine)palladium, palladium acetate, palladium dichloride, palladium trifluoroacetate, palladium on carbon, dichlorobis(triphenylphosphine)palladium; the copper-based catalyst is one or more of cuprous iodide, cuprous bromide, cuprous chloride, copper acetate, copper sulfate, copper chloride.

[0013] Preferably, in step S1, the polymerization reaction solution is a mixture of a polar solvent and a basic solvent, and the volume ratio of the polar solvent to the basic solvent is 5:1 to 1:5; the polar solvent is one or more of toluene, o-xylene, m-xylene, p-xylene, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, 1,4-dioxane, acetonitrile, dichloromethane, chloroform; the basic solvent is one or more of triethylamine, tripropylamine, tributylamine, pyrrolidine, pyridine, quinoline, isoquinoline; the in-situ crosslinking reaction temperature is 50 to 120 °C, and the time is 12 to 96 h.

[0014] Preferably, in step S2, the template removal solution is one or more of hydrofluoric acid etching solution, buffered oxide etching solution, fluorosilicic acid solution, sodium hydroxide solution, potassium hydroxide solution; the mass ratio of the template removal solution to the porous polymer-supported SiO2 is 1:10 to 1:100, and the etching treatment conditions are a temperature of 0 to 60 °C and a time of 0.5 to 24 h.

[0015] Preferably, in step S3, the graphene is one or more of graphene oxide, reduced graphene oxide, biomass-based graphene, monolayer graphene, bilayer graphene, few-layer graphene, multi-layer graphene, the lateral size of the graphene is 1 to 10 μm, and the number of layers is 1 to 50 layers; the dispersion medium is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, toluene, ethanol, water; the mass ratio of the porous polymer hollow microspheres to the graphene is 3:1 to 1:3.

[0016] Preferably, in step S3, the separation technology is one or more of filtration separation, centrifugal separation, sedimentation separation, evaporation separation, extraction separation, membrane separation technology.

[0017] Preferably, in step S3, the separation technology is filtration separation technology, and the parameter settings are: the pore size of the filter membrane is 0.1 to 1.0 μm, the filtration pressure is 0.1 to 0.9 MPa, and the filtration time is 10 to 60 min.

[0018] Preferably, in step S3, the separation technology is centrifugal separation technology, and the parameter settings are: the centrifugal speed is 1000 to 10000 rpm, and the centrifugal time is 5 to 60 min.

[0019] Preferably, in step S3, the separation technology is sedimentation separation technology, and the parameter settings are: the sedimentation time is 2 to 72 h, and the sedimentation temperature is 20 to 80 °C.

[0020] Preferably, in step S3, the separation technology is evaporation separation technology, and the parameter settings are: the evaporation temperature is 25 to 150 °C, the evaporation time is 10 to 60 min, and the evaporation pressure is 10 to 100 kPa.

[0021] Preferably, the solid recovery rate of the graphene-coated porous polymer obtained by separation is > 98 wt%, and the residual solvent is < 0.1 wt%.

[0022] Preferably, in step S4, the heat conductive agent is one or more of octadecanol, epoxy resin, polyethylene glycol, n-octadecane, n-eicosane, ionic liquid; the mass ratio of the graphene-coated porous polymer to the heat conductive agent is 1:3 to 1:30, and the temperature rise-induced phase change temperature is 40 to 120 °C.

[0023] To achieve the above object, according to the second aspect of the present invention, the present invention also provides an integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere obtained by the foregoing preparation method.

[0024] Preferably, the specific surface area of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere is 516 m 2 / g to 683 m 2 / g, the pore volume is 0.42 to 0.51 cm 3 / g, the thermal conductivity is 7.34 to 9.56 W / (m·K), and the thermal resistance is 2.14×10 -3 to 5.39×10 -3 m 2 ·K / W.

[0025] Applying the technical solution of the present invention, the beneficial effects of the present invention are as follows: (1) By forming a "heat conductive agent - graphene - porous polymer" three-layer sandwich structure, not only the specific surface area of the material is increased, but also the heat conduction path is optimized, so that the material realizes a dynamic balance between energy storage and heat dissipation; (2) Mixing the porous polymer hollow microsphere and graphene in a dispersion medium, preparing a graphene-coated porous polymer by separation and drying, and significantly improving the thermal conductivity of the material through the uniform coating of graphene; (3) By mixing the graphene-coated porous polymer with a heat conductive agent and inducing a phase change by heating, preparing a three-layer sandwich graphene porous polymer hollow microsphere, further optimizing the internal structure of the material, and realizing the perfect combination of energy storage and heat dissipation functions; (4) Each step interacts synergistically, and the prepared material has a three-layer sandwich structure, a high specific surface area, excellent heat conduction ability and ultra-low thermal resistance characteristics, and can be widely applied to new energy, data centers, buildings and other fields.

[0026] The present invention provides a three - layer sandwich - shaped graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions and a preparation method thereof. This material is prepared through steps such as in - situ cross - linking, etching, graphene coating, and filling with heat - conducting agents. It has significant characteristics such as a three - layer sandwich morphology, a large specific surface area, excellent heat - conducting ability, and an ultra - low thermal resistance. It can not only effectively integrate the functions of energy storage and heat dissipation, but also has advantages such as regular structure and adjustable size, and can be widely applied in fields such as building insulation, electronic heat dissipation, and energy storage. In the construction field, this material can be used as an efficient thermal insulation material to significantly reduce the energy consumption of buildings. In the electronic field, this material can be used for the heat dissipation management of electronic devices to improve the stability and lifespan of the devices. In the energy field, this material can be used for the thermal management of energy storage systems to optimize the energy conversion efficiency. In addition, this material can also be applied in multiple fields such as sensing, catalysis, and electromagnetic shielding, showing broad application prospects. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0028] Figure 1 It is a schematic flow chart of the method of the present invention.

[0029] Figure 2 It is a scanning electron microscope image of the three - layer sandwich - shaped graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions in Example 1.

[0030] Figure 3 It is an elemental mapping image of the three - layer sandwich - shaped graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions in Example 1.

[0031] Figure 4 It is a transmission electron microscope image of the three - layer sandwich - shaped graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions in Example 1.

[0032] Figure 5 It is a Fourier transform infrared spectrum diagram of the three - layer sandwich - shaped graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions in Example 1.

[0033] Figure 6 It is a nitrogen adsorption - desorption isotherm curve diagram of the three - layer sandwich - shaped graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions in Example 1.

[0034] Figure 7It is the thermogravimetric analysis curve of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres in Example 1.

[0035] Figure 8 It is the scanning electron microscope image of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres in Example 2.

[0036] Figure 9 It is the scanning electron microscope image of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres in Example 3.

[0037] Figure 10 It is the scanning electron microscope image of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres in Example 4. Detailed implementation manners

[0038] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts shall fall within the scope protected by the present invention. The present invention will be described in detail below in conjunction with the embodiments.

[0039] Such as Figure 1As shown, Example 1 of the present invention provides a method for preparing a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions, including the following steps: Step S11, preparing porous polymer-supported SiO2: Dispersing crystalline SiO2 (SiO2 particle size is 100 nm, agglomeration size is 50 nm), p-phenylene diacetylene, p-bromotoluene, tetrakis(triphenylphosphine)palladium and cuprous iodide in a polymerization reaction solution composed of toluene and triethylamine (the functional group molar ratio of p-phenylene diacetylene to p-bromotoluene is 1:1, the sum of p-phenylene diacetylene and p-bromotoluene and SiO2 molar ratio is 1:8, the molar ratio of tetrakis(triphenylphosphine)palladium to cuprous iodide is 2:1, the volume ratio of toluene and triethylamine is 1:1), and carrying out in-situ cross-linking reaction at 80 °C for 72 h to prepare porous polymer-supported SiO2; Step S12, preparing porous polymer hollow microspheres: Placing the porous polymer-supported SiO2 obtained in Step S11 in a hydrofluoric acid etching solution (the mass ratio of the template removal solution to the porous polymer-supported SiO2 is 1:20) and treating at 20 °C for 6 h to prepare porous polymer hollow microspheres; Step S13, preparing graphene-coated porous polymer: Compositing the porous polymer hollow microspheres obtained in Step S12 with reduced graphene oxide (lateral size is 2 μm, number of layers is 5 layers, the mass ratio of the porous polymer hollow microspheres to the reduced graphene oxide is 1:1) in N,N-dimethylformamide and filtering and separating (filter membrane pore size is 0.22 μm, filtration pressure is 0.5 MPa, filtration time is 30 min, solid recovery rate is 98.5 wt%, residual solvent is 0.05 wt%) to prepare graphene-coated porous polymer; Step S14, preparing three-layer sandwich graphene porous polymer hollow microspheres: Mixing the graphene-coated porous polymer obtained in Step S13 with octadecanol (the mass ratio of the graphene-coated porous polymer to octadecanol is 1:10) and inducing phase change at 70 °C to prepare three-layer sandwich graphene porous polymer hollow microspheres. The specific surface area of the obtained material is 683 m 2 / g, the pore volume is 0.51 cm 3 / g, the thermal conductivity is 9.56 W / (m·K), and the thermal resistance is 2.14×10 -3 m 2 ·K / W.

[0040] As Figure 2 shown, the scanning electron microscope image of the three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions obtained in Example 1 of the present invention shows that the material has a smooth microsphere structure on the surface, and the microstructure of the hollow sphere is not damaged.

[0041] As Figure 3 shown, the elemental mapping image of the three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions obtained in Example 1 of the present invention shows that carbon, nitrogen and oxygen elements are evenly distributed on the surface of the material.

[0042] As Figure 4 shown, the transmission electron microscope image of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres obtained in Example 1 of the present invention indicates that there is an obvious three-layer sandwich structure of "heat conduction agent - graphene - porous polymer" in the material.

[0043] As Figure 5 shown, the Fourier transform infrared spectrum of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres obtained in Example 1 of the present invention indicates that the material has signal peaks such as –OH, C Ar –H, –C≡C–, etc., proving the successful synthesis of the porous polymer.

[0044] As Figure 6 shown, the nitrogen adsorption - desorption isotherm curve of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres obtained in Example 1 of the present invention indicates that the material has a full-size continuous distribution of pore sizes from micropores to mesopores to macropores and an excellent specific surface area.

[0045] As Figure 7 shown, the thermogravimetric analysis curve of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres obtained in Example 1 of the present invention indicates that the material has good thermal decomposition temperature and thermal stability, and can meet the actual requirements under different working conditions.

[0046] Example 2 of the present invention provides a method for preparing a three - layer sandwich graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions, comprising the following steps: Step S21, preparing porous polymer - loaded SiO2: Amorphous SiO2 (SiO2 particle size is 150 nm, agglomeration size is 80 nm), m - phenylenediacetylene, m - chloroaniline, palladium acetate and cuprous bromide are dispersed in a reaction mixture composed of o - xylene and tripropylamine (the molar ratio of functional groups of m - phenylenediacetylene to m - chloroaniline is 3:1, the total molar ratio of m - phenylenediacetylene and m - chloroaniline to SiO2 is 1:5, the molar ratio of palladium acetate to cuprous bromide is 3:1, and the volume ratio of o - xylene to tripropylamine is 2:1), and an in - situ cross - linking reaction is carried out at 70 °C for 48 h to prepare porous polymer - loaded SiO2; Step S22, preparing porous polymer hollow microspheres: The porous polymer - loaded SiO2 obtained in Step S21 is placed in a buffered oxide etchant (the mass ratio of the template removal solution to the porous polymer - loaded SiO2 is 1:10) and treated at 0 °C for 3 h to prepare porous polymer hollow microspheres; Step S23, preparing graphene - coated porous polymer: The porous polymer hollow microspheres obtained in Step S22 and graphene oxide (lateral size is 1 μm, number of layers is 3 layers, the mass ratio of the porous polymer hollow microspheres to reduced graphene oxide is 2:1) are compounded in N,N - dimethylacetamide and centrifuged (centrifugation speed is 8000 rpm, centrifugation time is 10 min, solid recovery rate is 98 wt%, residual solvent is 0.1 wt%) to prepare graphene - coated porous polymer; Step S24, preparing a three - layer sandwich graphene - porous polymer hollow microsphere: The graphene - coated porous polymer obtained in Step S23 is mixed with epoxy resin (the mass ratio of the graphene - coated porous polymer to the epoxy resin is 1:5) and induced phase change is carried out at 60 °C to prepare a three - layer sandwich graphene - porous polymer hollow microsphere. The specific surface area of the obtained material is 607 m 2 / g, the pore volume is 0.48 cm 3 / g, the thermal conductivity is 8.42 W / (m·K), and the thermal resistance is 3.58×10 -3 m 2 ·K / W.

[0047] As Figure 8 shown, the scanning electron microscope image of the three - layer sandwich graphene - porous polymer hollow microsphere with integrated energy storage and heat dissipation functions obtained in Example 2 of the present invention shows that the material has a microsphere structure with a smooth surface, and the microstructure of the hollow sphere is not damaged.

[0048] Example 3 of the present invention provides a method for preparing a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions, including the following steps: Step S31, preparing porous polymer-supported SiO2: Dispersing mesoporous SiO2 (SiO2 particle size is 200 nm, agglomeration size is 100 nm), 1,3,5-triethynylbenzene, p-dibromobenzene, palladium dichloride and copper chloride in a polymerization reaction solution composed of N,N-dimethylformamide and tributylamine (the molar ratio of the functional groups of 1,3,5-triethynylbenzene to p-dibromobenzene is 1:2, the total molar ratio of 1,3,5-triethynylbenzene and p-dibromobenzene to SiO2 is 1:10, the molar ratio of palladium dichloride to copper chloride is 1:1, and the volume ratio of N,N-dimethylformamide to tributylamine is 1:2), and carrying out an in-situ cross-linking reaction at 90 °C for 84 h to prepare porous polymer-supported SiO2; Step S32, preparing porous polymer hollow microspheres: Placing the porous polymer-supported SiO2 obtained in Step S31 in a fluosilicic acid solution (the mass ratio of the template removal solution to the porous polymer-supported SiO2 is 1:30) and treating it at 40 °C for 8 h to prepare porous polymer hollow microspheres; Step S33, preparing graphene-coated porous polymer: Compositing and sedimentation separating the porous polymer hollow microspheres obtained in Step S32 with few-layer graphene (the lateral size is 3 μm, the number of layers is 4 layers, and the mass ratio of the porous polymer hollow microspheres to the few-layer graphene is 1:2) in dimethyl sulfoxide (the sedimentation time is 24 h, the sedimentation temperature is 30 °C, the solid recovery rate is 99 wt%, and the residual solvent is 0.07 wt%) to prepare graphene-coated porous polymer; Step S34, preparing a three-layer sandwich graphene porous polymer hollow microsphere: Mixing the graphene-coated porous polymer obtained in Step S33 with polyethylene glycol (the mass ratio of the graphene-coated porous polymer to polyethylene glycol is 1:15) and inducing phase change at 80 °C to prepare a three-layer sandwich graphene porous polymer hollow microsphere. The specific surface area of the obtained material is 552 m 2 / g, the pore volume is 0.45 cm 3 / g, the thermal conductivity is 7.71 W / (m·K), and the thermal resistance is 4.41×10 -3 m 2 ·K / W.

[0049] As Figure 9 shown, the scanning electron microscope image of the three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions obtained in Example 3 of the present invention shows that the material has a smooth microsphere structure on the surface, and the microstructure of the hollow sphere is not damaged.

[0050] Example 4 of the present invention provides a method for preparing a three - layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions, comprising the following steps: Step S41, preparing porous polymer - loaded SiO2: Dispersing porous SiO2 (the particle size of SiO2 is 250 nm and the agglomeration size is 150 nm), 1,6,8,13 - tetraethynylpyrene, m - dibromobenzene, palladium trifluoroacetate and copper acetate in a polymerization reaction solution composed of tetrahydrofuran and pyrrolidine (the molar ratio of the functional groups of 1,6,8,13 - tetraethynylpyrene to m - dibromobenzene is 1:3, the sum of 1,3,5 - triethynylbenzene and p - dibromobenzene and SiO2 has a molar ratio of 1:15, the molar ratio of palladium trifluoroacetate to copper acetate is 1:2, and the volume ratio of tetrahydrofuran to pyrrolidine is 1:3), and carrying out an in - situ cross - linking reaction at 100 °C for 96 h to prepare porous polymer - loaded SiO2; Step S42, preparing porous polymer hollow microspheres: Placing the porous polymer - loaded SiO2 obtained in Step S41 in a sodium hydroxide solution (the mass ratio of the template removal solution to the porous polymer - loaded SiO2 is 1:40) and treating it at 60 °C for 12 h to prepare porous polymer hollow microspheres; Step S43, preparing graphene - coated porous polymer: Compositing the porous polymer hollow microspheres obtained in Step S42 with multi - layer graphene (the lateral size is 5 μm, the number of layers is 10, and the mass ratio of the porous polymer hollow microspheres to the multi - layer graphene is 1:3) in ethanol and separating by evaporation (the evaporation temperature is 80 °C, the evaporation time is 20 min, the evaporation pressure is 50 kPa, the solid recovery rate is 99.5 wt%, and the residual solvent is 0.04 wt%) to prepare a graphene - coated porous polymer; Step S44, preparing a three - layer sandwich graphene porous polymer hollow microsphere: Mixing the graphene - coated porous polymer obtained in Step S43 with an ionic liquid (the mass ratio of the graphene - coated porous polymer to the ionic liquid is 1:20) and inducing a phase change at 90 °C to prepare a three - layer sandwich graphene porous polymer hollow microsphere. The specific surface area of the obtained material is 516 m 2 / g, the pore volume is 0.42 cm 3 / g, the thermal conductivity is 7.34 W / (m·K), and the thermal resistance is 5.39×10 -3 m 2 ·K / W.

[0051] As Figure 10 shown, the scanning electron microscope image of the three - layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions obtained in Example 3 of the present invention shows that the material has a microsphere structure with a smooth surface, and the microscopic structure of the hollow sphere is not damaged.

[0052] Comparative Example 1 of the present invention provides a method for preparing a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions, which basically adopts the method of Example 1 to prepare a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions. The difference is that in this example, silica is not used as a sacrificial template to prepare a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions. Specifically, p-phenylene diacetylene, p-bromotoluene, tetrakis(triphenylphosphine)palladium, and copper iodide are dispersed in a polymerization reaction solution composed of toluene and triethylamine (the molar ratio of the functional groups of p-phenylene diacetylene to p-bromotoluene is 1:1, the molar ratio of tetrakis(triphenylphosphine)palladium to copper iodide is 2:1, and the volume ratio of toluene to triethylamine is 1:1), and an in-situ cross-linking reaction is carried out at 80 °C for 72 h to prepare a porous polymer; the obtained porous polymer is compounded with reduced graphene oxide (the lateral size is 2 μm, the number of layers is 5 layers, and the mass ratio of the porous polymer to reduced graphene oxide is 1:1) in N,N-dimethylformamide and filtered and separated (the pore size of the filter membrane is 0.22 μm, the filtration pressure is 0.5 MPa, the filtration time is 30 min, the solid recovery rate is 98.5 wt%, and the residual solvent is 0.05 wt%) to prepare graphene-coated porous polymer; the obtained graphene-coated porous polymer is mixed with octadecyl alcohol (the mass ratio of the graphene-coated porous polymer to octadecyl alcohol is 1:10) and induced to undergo a phase change at 70 °C to prepare a three-layer sandwich graphene porous polymer.

[0053] Comparative Example 2 of the present invention provides a method for preparing a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions, which basically adopts the method of Example 2 to prepare a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions. The difference is that in this example, a graphene coating layer is not used to prepare a three-layer sandwich graphene porous polymer hollow microsphere with integrated energy storage and heat dissipation functions. Specifically, amorphous SiO2 (the particle size of SiO2 is 150 nm, and the agglomeration size is 80 nm), m-phenylene diacetylene, m-chloroaniline, palladium acetate, and copper bromide are dispersed in a polymerization reaction solution composed of o-xylene and tripropylamine (the molar ratio of the functional groups of m-phenylene diacetylene to m-chloroaniline is 3:1, the total molar ratio of m-phenylene diacetylene and m-chloroaniline to SiO2 is 1:5, the molar ratio of palladium acetate to copper bromide is 3:1, and the volume ratio of o-xylene to tripropylamine is 2:1), and an in-situ cross-linking reaction is carried out at 70 °C for 48 h to prepare a porous polymer loaded with SiO2; the obtained porous polymer loaded with SiO2 is placed in a buffered oxide etchant (the mass ratio of the template removal solution to the porous polymer loaded with SiO2 is 1:10) and treated at 0 °C for 3 h to prepare a porous polymer hollow microsphere; the obtained porous polymer hollow microsphere is mixed with epoxy resin (the mass ratio of the porous polymer hollow microsphere to epoxy resin is 1:5) and induced to undergo a phase change at 60 °C to prepare a double-layer porous polymer hollow microsphere.

[0054] Comparative Example 3 of the present invention provides a method for preparing an integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere, which basically adopts the method of Example 3 to prepare the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere. The difference is that in this example, no heat conductive agent is added to prepare the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere. Specifically, mesoporous SiO2 (SiO2 particle size is 200 nm, agglomeration size is 100 nm), 1,3,5-triethynylbenzene, p-dibromobenzene, palladium dichloride and copper chloride are dispersed in a polymerization reaction solution composed of N,N-dimethylformamide and tributylamine (the molar ratio of the functional groups of 1,3,5-triethynylbenzene to p-dibromobenzene is 1:2, the total molar ratio of 1,3,5-triethynylbenzene and p-dibromobenzene to SiO2 is 1:10, the molar ratio of palladium dichloride and copper chloride is 1:1, and the volume ratio of N,N-dimethylformamide and tributylamine is 1:2), and an in-situ cross-linking reaction is carried out at 90 °C for 84 h to prepare porous polymer-supported SiO2; the obtained porous polymer-supported SiO2 is placed in a fluorosilicic acid solution (the mass ratio of the template removal solution to the porous polymer-supported SiO2 is 1:30) and treated at 40 °C for 8 h to prepare porous polymer hollow microspheres; the obtained porous polymer hollow microspheres and few-layer graphene (the lateral size is 3 μm, the number of layers is 4 layers, and the mass ratio of the porous polymer hollow microspheres to the few-layer graphene is 1:2) are compounded and sedimentation-separated in dimethyl sulfoxide (the sedimentation time is 24 h, the sedimentation temperature is 30 °C, the solid recovery rate is 99 wt%, and the residual solvent is 0.07 wt%) to prepare double-layer graphene-coated porous polymer hollow microspheres.

[0055] The structure characterization and performance testing are as follows.

[0056] Scanning electron microscope observation: The microstructures of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres are observed by a field emission scanning electron microscope (model JSM-7900F, JEOL, Japan) ( Figure 2 , Figure 8 , Figure 9 , Figure 10 ).

[0057] Surface element distribution test: The surface element distributions of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres are recorded by an energy dispersive X-ray spectrometer (model Vario EL, JEOL, Japan) ( Figure 3 ).

[0058] Transmission electron microscope observation: The internal characteristics of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres are observed by a transmission electron microscope (model TECNI G2 TF20, FEI) ( Figure 4 ).

[0059] Functional group structure test: An infrared spectrometer (model VERTEX 70, Bruker, USA) was used to record the functional groups of the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres ( Figure 5 ).

[0060] Specific surface area test: A gas adsorption instrument (ASAP 2060, Micromeritics, USA) was used to measure the specific surface area and pore volume parameters of the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres at 77 K ( Figure 6 ).

[0061] Thermal stability test: A thermogravimetric analyzer (Pyris I, Perkin Elmer, USA) was used to test the heat resistance and thermal decomposition of the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres from room temperature to 800 °C ( Figure 7 ).

[0062] Energy storage and heat dissipation performance test: A hot plate thermal conductivity meter was used to calculate the thermal conductivity and thermal resistance parameters by measuring the temperature difference and heat flow on both sides of the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres through the steady-state method after the heat flow was stable.

[0063] Experimental results: As Figure 2 , Figure 8 , Figure 9 and Figure 10 shown, the scanning electron microscope images indicate that the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres have a smooth microsphere structure on the surface, and the microstructure of the hollow spheres is not damaged.

[0064] As Figure 3 shown, the elemental mapping images indicate that carbon, nitrogen, and oxygen elements are uniformly distributed on the surface of the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres.

[0065] As Figure 4 shown, the transmission electron microscope images indicate that there is an obvious "thermal conductive agent - graphene - porous polymer" three-layer sandwich structure in the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres.

[0066] As Figure 5 shown, the Fourier transform infrared spectroscopy diagram indicates the presence of signal peaks such as –OH, C Ar –H, and –C≡C– in the structure of the integrated energy storage and heat dissipation three-layer sandwich graphene porous polymer hollow microspheres, proving the successful synthesis of the porous polymer.

[0067] As Figure 6As shown, the nitrogen adsorption - desorption isotherm curve indicates that the integrated energy storage and heat dissipation three - layer sandwich graphene porous polymer hollow microspheres have a full - size continuous distribution of pore sizes from micropores to mesopores to macropores and an excellent specific surface area.

[0068] As Figure 7 shown, the thermogravimetric analysis curve shows that the integrated energy storage and heat dissipation three - layer sandwich graphene porous polymer hollow microspheres have a good thermal decomposition temperature and thermal stability, which can meet the actual requirements under different working conditions.

[0069] Table 1 compares the specific surface area, pore volume, thermal conductivity and thermal resistance results of the integrated energy storage and heat dissipation three - layer sandwich graphene porous polymer hollow microspheres obtained in the examples and comparative examples.

[0070] Project Group <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Thermal Conductivity (W / (m·K)) <![CDATA[Thermal resistance (m 2 ·K / W)]]> Example 1 683 0.51 9.56 <![CDATA[2.14×10 -3 > Example 2 607 0.48 8.42 <![CDATA[3.58×10 -3 > Example 3 552 0.45 7.71 <![CDATA[4.41×10 -3 > Example 4 516 0.42 7.34 <![CDATA[5.39×10 -3 > Comparative Example 1 148 0.16 0.21 0.06 Comparative Example 2 173 0.19 0.15 0.35 Comparative Example 3 185 0.22 0.09 0.67 Examples 1 - 4 have a relatively high specific surface area (516 m 2 / g - 683 m 2 / g) and a relatively large pore volume (0.42 cm 3 / g - 0.51 cm 3 / g). This is because silica is used as a growth template to grow the porous polymer uniformly and orderly on its surface, and then the silica is etched through the template sacrifice strategy to obtain the porous polymer hollow microspheres, thus fully exposing the pore properties of the material; the specific surface areas of Comparative Examples 1 - 3 are only 148 - 185 m 2 / g, and the pore volumes are 0.16 cm 3 / g - 0.22 cm 3 / g. This is because the ordered self - assembly or uniform coating of the porous polymer is not controlled, thus affecting the growth process and pore properties.

[0071] The energy storage and heat dissipation functions of the three - layer sandwich graphene porous polymer hollow microspheres are closely related to the specific surface area, pore volume, and the coating of graphene and heat conducting agent. The thermal conductivities of Examples 1 - 4 with a relatively high specific surface area, a relatively large pore volume, and uniform coating of graphene and heat conducting agent are all above 7.34 W / (m·K), and the thermal resistances are all below 5.39×10 -3 m 2 ·K / W. Among them, Example 1 with the highest specific surface area, the largest pore volume, and the optimal uniform coating ratio of graphene and heat conducting agent performs the best in the energy storage and heat dissipation test, with a thermal conductivity of 9.56 W / (m·K) and a thermal resistance of 2.14×10 -3 m 2 ·K / W. It is much higher than Comparative Examples 1 - 3 with a low specific surface area, a small pore volume, and non - uniform coating of graphene and heat conducting agent (thermal conductivity ≤ 0.21 W / (m·K), thermal resistance ≥ 0.06 m 2·K / W).

[0072] The present invention provides an integrated three-layer sandwich graphene porous polymer hollow microsphere with energy storage and heat dissipation functions and a preparation method thereof. There are many specific methods and ways to implement this technical solution. The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by existing technologies.

Claims

1. Preparation method of an integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere, characterized in that, It includes the following steps: Step S1: Disperse silica, alkynyl monomer, halogen monomer and catalyst in a polymerization reaction solution to prepare porous polymer-supported silica; Step S2: Add the porous polymer-supported silica obtained in Step S1 into a template removal solution to prepare porous polymer hollow microspheres; Step S3: Compound graphene, a dispersion medium and the porous polymer hollow microspheres obtained in Step S2, and prepare graphene-coated porous polymer through a separation technique; Step S4: Mix a heat-conducting agent with the graphene-coated porous polymer obtained in Step S3, and prepare an integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere through induced phase change.

2. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microspheres with energy storage and heat dissipation functions according to claim 1, characterized in that In Step S1, the alkynyl monomer is one or more of p-phenylene diacetylene, m-phenylene diacetylene, 1,3,5-triethynylbenzene, 1,3,5-tris(bromoethynyl)benzene, tris(4-bromoethynylphenyl)amine, 1,6,8,13-tetraethynylpyrene, 1,2,4,5-tetrakis(bromoethynyl)benzene, and the halogen monomer is one or more of p-bromotoluene, m-chloroaniline, p-dibromobenzene, m-dibromobenzene, o-dibromobenzene, 1,4-dichlorobenzene, 1,4-diiodobenzene, 1,3,5-tribromobenzene; the molar ratio of the functional groups of the alkynyl monomer to the halogen monomer is 5:1 to 1:

5.

3. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microsphere with energy storage and heat dissipation functions according to claim 1, characterized in that, In Step S1, the silica is one or more of crystalline silica, amorphous silica, mesoporous silica, porous silica, fumed silica, liquid silica, solid silica; the molar ratio of the sum of the alkynyl monomer and the halogen monomer to silica is 1:5 to 1:

15.

4. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microsphere with energy storage and heat dissipation functions according to claim 1, wherein, In Step S1, the catalyst is a mixture of a palladium-based catalyst and a copper-based catalyst, and the molar ratio of the palladium-based catalyst to the copper-based catalyst is 5:1 to 1:20; the palladium-based catalyst is one or more of tetrakis(triphenylphosphine)palladium, palladium acetate, palladium dichloride, palladium trifluoroacetate, palladium on carbon, dichlorobis(triphenylphosphine)palladium; the copper-based catalyst is one or more of cuprous iodide, cuprous bromide, cuprous chloride, copper acetate, copper sulfate, copper chloride.

5. The preparation method of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microspheres according to claim 1, characterized in that, In Step S1, the polymerization reaction solution is a mixture of a polar solvent and a basic solvent, and the volume ratio of the polar solvent to the basic solvent is 5:1 to 1:5; the polar solvent is one or more of toluene, o-xylene, m-xylene, p-xylene, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, 1,4-dioxane, acetonitrile, dichloromethane, chloroform; the basic solvent is one or more of triethylamine, tripropylamine, tributylamine, pyrrolidine, pyridine, quinoline, isoquinoline; the reaction conditions of Step S1 are that the temperature is 50 to 120 °C and the time is 12 to 96 h.

6. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microspheres with energy storage and heat dissipation functions according to claim 1, characterized in that In Step S2, the template removal solution is one or more of hydrofluoric acid etching solution, buffered oxide etching solution, fluorosilicic acid solution, sodium hydroxide solution, potassium hydroxide solution; the mass ratio of the template removal solution to the porous polymer-supported silica is 1:10 to 1:100, and the reaction conditions of Step S2 are that the temperature is 0 to 60 °C and the time is 0.5 to 24 h.

7. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microsphere with energy storage and heat dissipation functions according to claim 1, characterized in that, In step S3, the graphene is one or more of graphene oxide, reduced graphene oxide, biomass-based graphene, monolayer graphene, bilayer graphene, few-layer graphene, and multilayer graphene. The lateral size of the graphene is 1 to 10 μm, and the number of layers is 1 to 50 layers. The dispersion medium is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, toluene, ethanol, and water. The mass ratio of the porous polymer hollow microspheres to the graphene is 3:1 to 1:

3.

8. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microspheres with energy storage and heat dissipation functions according to claim 1, characterized in that In step S3, the separation technique is one or more of filtration separation, centrifugal separation, sedimentation separation, evaporation separation, extraction separation, and membrane separation techniques.

9. The preparation method of the integrated three-layer sandwich graphene porous polymer hollow microspheres with energy storage and heat dissipation functions according to claim 1, characterized in that, In step S4, the heat conductive agent is one or more of octadecanol, epoxy resin, polyethylene glycol, n-octadecane, n-eicosane, and ionic liquid. The mass ratio of the graphene-coated porous polymer to the heat conductive agent is 1:3 to 1:20, and the induced phase change temperature is 40 to 90 °C.

10. A graphene porous polymer hollow microsphere prepared by the preparation method of the integrated energy storage and heat dissipation functional three-layer sandwich graphene porous polymer hollow microsphere according to any one of claims 1 to 9.

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