A phase change composite graphene oxide aerogel microsphere and a preparation method thereof

Abstract

The application discloses a kind of phase change composite graphene oxide aerogel microspheres and preparation method thereof, comprising the following steps: step 1, graphene oxide is placed in solvent, after stirring, cell crushing and ultrasonic treatment are carried out, and stable graphene oxide dispersion is obtained;Step 2, phase change material is added in graphene oxide dispersion, after stirring and completely dissolving, coupling agent and catalyst are added, condensation reflux reaction is carried out under nitrogen atmosphere for a certain time, esterification reaction occurs, grafting is completed, and grafting product is obtained after acid washing, freeze drying;Step 3, grafting product is placed in solvent, and stable grafting product dispersion is obtained by ultrasonic dispersion;The oil phase containing emulsifier is mixed with grafting product dispersion, and stable O / W type Pickering emulsion is formed by high-speed stirring, and phase change composite graphene oxide aerogel microspheres are obtained after rapid freezing with liquid nitrogen and freeze drying, and the obtained aerogel microspheres have good heat enthalpy value and thermal cycle performance.

Description

Technical Field

[0001] This invention relates to the field of phase change composite materials, specifically to a phase change composite graphene oxide aerogel microsphere and its preparation method. Background Technology

[0002] Phase change materials (PCMs) are materials that regulate temperature through phase changes during the melting process. They can store and release energy during this phase change and are widely used in aerospace, solar energy, and battery thermal management systems. Compared to inorganic and eutectic PCMs, organic PCMs have advantages such as higher latent heat of phase change, non-toxicity, non-corrosiveness, high heat storage density, and ease of temperature regulation. However, during use, PCMs have poor thermal conductivity, resulting in slow response to heat changes, lower energy storage capacity, and are prone to liquefaction above their melting point. They also exhibit poor shape stability and significant leakage, limiting their applications in energy storage. To meet usage requirements, PCMs are typically encapsulated within a matrix material, commonly using capsule encapsulation and porous framework encapsulation. Porous frameworks not only enhance thermal conductivity but also utilize capillary forces and surface adsorption effects to stabilize the PCM within the pores. Aerogel microspheres are three-dimensional structures formed by interconnected nanostructured particles. They have micron-sized particles and advantages such as ultra-low density, large pore volume, high specific surface area, easy processing, and wide range of applications. They are an effective carrier for encapsulating phase change materials.

[0003] Graphene is a matrix material with good thermal conductivity and stability, featuring a single-layer sheet structure and a thermal conductivity as high as 5300 W / (m·K). It also possesses excellent optoelectronic properties. The surface of graphene oxide has numerous functional groups, which facilitates grafting and encapsulation with phase change materials, and the formation of ultralight porous microspheres through planar folding assembly. In particular, it offers significant advantages as a temperature control material for electronic devices, and can be applied to the thermal management of batteries and electronic components, improving performance and lifespan.

[0004] Currently, research on graphene-based aerogel microspheres mainly focuses on their preparation methods. The main preparation methods include coagulation bath crosslinking and electrospinning / freeze casting. Patent CN106185908A combines emulsion and freeze-drying methods to prepare micron-sized graphene aerogel microspheres, resulting in microspheres with regular morphology, uniform size, and a porous network structure. Patent CN113825379A prepares graphene aerogel microspheres filled with magnetic MOFs through electrostatic spraying, freeze-drying, and high-temperature heat treatment in an inert gas atmosphere. Patent CN114525112A prepares a bifunctional polyethylene glycol / graphene aerogel composite phase change material with ultra-high loading capacity, exhibiting high heat storage density and good stability, and can be applied in batteries, construction, and other fields. Current research on the preparation of aerogel microspheres does not incorporate phase change functional materials. Furthermore, phase change composite graphene aerogels are mostly bulk structures, requiring sophisticated equipment, resulting in low production efficiency and hindering mass production, thus limiting the applications of graphene aerogels. Microspherical graphene aerogels, with their larger specific surface area and controllable shape and size, can better adapt to practical applications, especially in micro-environments or with added matrices, broadening their application scenarios. Therefore, the preparation of a phase change composite graphene aerogel microsphere is of significant importance. Summary of the Invention

[0005] The purpose of this invention is to design a phase change composite graphene oxide aerogel microsphere and its preparation method, which utilizes the Pickering emulsion method to achieve mass production. This method provides a new approach for the encapsulation of phase change materials and temperature control of micro-devices. It employs a grafting method between graphene oxide sheets and organic phase change materials, and through directional assembly in a Pickering emulsion, effectively controls the microstructure of the materials, resulting in phase change composite aerogel microspheres with high grafting rates and controllable structures. These microspheres can be applied to electronic devices and battery thermal management, thereby improving their efficiency and safety.

[0006] To achieve the above objectives, this invention provides a method for preparing phase change composite graphene oxide aerogel microspheres, comprising the following steps:

[0007] Step 1, Preparation of graphene oxide dispersion: Graphene oxide is placed in a solvent, stirred, and then subjected to cell pulverization and ultrasonic treatment to obtain a stable and uniform graphene oxide dispersion.

[0008] Step 2, grafting phase change material onto graphene sheets: Add phase change material to graphene oxide dispersion, stir to dissolve completely, then add coupling agent and catalyst, and reflux the reaction system under nitrogen atmosphere for a certain time to undergo esterification reaction to complete grafting. After acid washing and freeze drying, the grafted product is obtained.

[0009] Step 3, Preparation of phase change composite aerogel microspheres by Pickering emulsion method: The grafted product is placed in a solvent and ultrasonically dispersed to obtain a stable grafted product dispersion; the oil phase containing emulsifier is mixed with the grafted product dispersion and stirred at high speed to form a stable O / W type Pickering emulsion, which is then rapidly frozen with liquid nitrogen and freeze-dried to obtain phase change composite graphene oxide aerogel microspheres.

[0010] Furthermore, the solvent is any one of distilled water, dimethylformamide, ethanol, and methanol.

[0011] Furthermore, in step 2, the phase change material is a single or compounded polyethylene glycol with a molecular weight range of 1000–6000, or / and

[0012] Single or compounded polyethylene glycol monomethyl ethers with a molecular weight range of 1000 to 5000.

[0013] Furthermore, the coupling agent in step 2 is any one of dicyclohexylcarbodiimide, triallyl isocyanurate, and diphenylmethane diisocyanate.

[0014] Furthermore, the catalyst in step 2 is any one of dimethylaminopyridine, dibutyltin maleate, and dibutyltin dilaurate.

[0015] Furthermore, in step 3, the oil phase is any one of xylene, toluene, or benzene.

[0016] Furthermore, the emulsifier in step 3 is any one or more compound emulsifiers selected from sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, Span 80, and Tween 80.

[0017] Furthermore, in step 3, the oil-water volume ratio of the oil phase and the water phase is in the range of 1:1 to 1:8.

[0018] The present invention also provides a phase change composite graphene oxide aerogel microsphere, which is prepared by the above-described preparation method.

[0019] The present invention also provides an application of phase change composite graphene oxide aerogel microspheres, which are used for thermal management of batteries or electronic devices.

[0020] Compared with the prior art, the beneficial effects of this invention are as follows:

[0021] (1) The method for preparing phase change composite graphene oxide aerogel microspheres provided by the present invention is simple. It can prepare loosely folded phase change composite aerogel microspheres in batches. The phase change temperature range is 30 to 80℃, the phase change enthalpy is 60 to 140 J / g, and the size is about 10 to 50 μm. The size is controllable and easy to disperse in the matrix, which can meet more needs in practical applications, broaden the application scenarios, and make it possible to apply to micro devices.

[0022] (2) The phase change composite graphene oxide aerogel microsphere material provided by the present invention can be used as a matrix material with relatively good thermal conductivity. The method of grafting graphene oxide aerogel with phase change material solves the problem of leakage that occurs during the application of phase change material, making it more stable in physical and chemical properties, with an adjustable phase change temperature range, high enthalpy value, good thermal cycling performance and thermal stability, and excellent thermal conductivity. It can be applied to phase change energy storage fields such as battery and electronic device temperature control. Attached Figure Description

[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0024] Figure 1 This is a scanning electron microscope image of the phase change composite graphene oxide aerogel microspheres of Example 1 of the present invention;

[0025] Figure 2 This is a differential scanning calorimetry (DSC) image of the phase change composite graphene oxide aerogel microspheres of Example 1 of the present invention.

[0026] Figure 3 The infrared spectrum of the phase change composite graphene oxide aerogel microspheres of Example 1 of the present invention is shown below.

[0027] Figure 4 This is an X-ray diffraction pattern of the phase change composite graphene oxide aerogel microspheres of Example 1 of the present invention. Detailed Implementation

[0028] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] This invention discloses a method for preparing phase change composite graphene oxide aerogel microspheres, comprising the following steps:

[0030] Step 1, Preparation of graphene oxide dispersion

[0031] Graphene oxide was dispersed in a solvent to prepare a solution of 2–6 mg / mL. After stirring, the solution was subjected to cell disruption for 30–60 min and ultrasonic treatment for 30–60 min to ensure that there was no obvious sedimentation and that the solution was a stable and uniform dispersion.

[0032] The solvent used for dispersion is any one of distilled water, dimethylformamide, ethanol, and methanol.

[0033] Step 2, grafting phase change materials onto graphene sheets

[0034] A phase change material (PCM) was added to the dispersion, with a molar ratio of graphene oxide to PCM of 1:2. The mixture was stirred for 10–30 min until completely dissolved. Then, a coupling agent and a catalyst were added, with a molar ratio of coupling agent to PCM of 1:5 and a molar ratio of catalyst to PCM of 1:60. The reaction system was refluxed at 60–80 °C under a nitrogen atmosphere for 6–8 h to induce esterification and complete the grafting process. Hydrochloric acid was added dropwise to adjust the pH to 3, and the reaction mixture was washed repeatedly with deionized water by centrifugation to remove excess reactants. The resulting sample was freeze-dried for 24 h to obtain the grafted product.

[0035] The phase change material is a single or compounded polyethylene glycol with a molecular weight range of 1000–6000, or / and

[0036] Single or compounded polyethylene glycol monomethyl ethers with a molecular weight range of 1000 to 5000.

[0037] The coupling agent is selected from any one of dicyclohexylcarbodiimide, triallyl isocyanurate, and diphenylmethane diisocyanate; the catalyst is selected from any one of dimethylaminopyridine, dibutyltin maleate, and dibutyltin dilaurate.

[0038] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0039] The grafted product was dispersed in a solvent to prepare a solution of 2-8 mg / mL, and ultrasonically dispersed for 20-60 min to obtain a stable dispersion. 5-50 mL of oil phase containing 20-60 mg of emulsifier was mixed with the water phase, with an oil-to-water volume ratio of 1:1 to 1:8. The mixture was stirred at high speed for 30 s using a homogenizer to form a stable O / W type Pickering emulsion. The emulsion was rapidly frozen with liquid nitrogen for 0.5-1 h and then freeze-dried for 48-72 h to obtain phase change composite graphene oxide aerogel microspheres.

[0040] The solvent is any one of distilled water, dimethylformamide, ethanol, and methanol;

[0041] The oil phase is any one of xylene, toluene, or benzene;

[0042] The emulsifier is any one or more compound emulsifiers selected from sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, Span 80, and Tween 80.

[0043] The preparation method described above will be further explained below with reference to specific embodiments.

[0044] Example 1

[0045] Step 1, Preparation of graphene oxide dispersion

[0046] 100 mg of graphene oxide was dispersed in 50 mL of N,N-dimethylformamide, stirred, and then subjected to cell disruption for 60 min and ultrasonic treatment for 60 min to ensure that there was no obvious sedimentation and that a stable and uniform dispersion was formed.

[0047] Step 2: Grafting graphene sheets with polyethylene glycol monomethyl ether 5000

[0048] Add 600 mg of polyethylene glycol monomethyl ether 5000 to the dispersion and stir for 30 min until completely dissolved. Then add 80 mg of dicyclohexylcarbodiimide and 10 mg of N,N-dimethyl-4-aminopyridine. Heat the reaction system to 60 °C under nitrogen atmosphere and reflux for 6 h to induce esterification and complete the grafting reaction. Adjust the pH to 3 with hydrochloric acid dropwise, and wash the reaction mixture repeatedly with deionized water by centrifugation to remove excess reactants. Freeze-dry the resulting sample for 24 h to obtain the grafted product.

[0049] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0050] 100 mg of the grafted product was dispersed in 40 mL of distilled water and ultrasonically dispersed for 20 min to obtain a stable dispersion. 10 mL of xylene containing 20 mg of sodium dodecyl sulfate was mixed with the aqueous phase at an oil-to-water volume ratio of 1:4. The mixture was stirred at high speed for 30 s using a homogenizer to form a stable O / W type Pickering emulsion. The emulsion was then rapidly frozen with liquid nitrogen for 0.5 h and freeze-dried for 48 h to obtain phase change composite graphene oxide aerogel microspheres.

[0051] Scanning electron microscope (SEM) images of the phase change composite graphene oxide aerogel microspheres prepared in this embodiment are shown below. Figure 1 As shown, the obtained product has a relatively clear spherical structure; the differential scanning calorimetry curve is shown in the figure. Figure 2 As shown, the enthalpy value is relatively high during the phase transition, ranging from 50 to 60 J / g; the infrared spectrum is as follows. Figure 3 As shown, a new characteristic peak appears, representing the absorption peak of the C=O double bond of the ester group. This characteristic peak indicates that an esterification reaction has occurred; the X-ray diffraction pattern is as follows. Figure 4 As shown, the composite material exhibits characteristic peaks at 2θ = 11° and 2θ = 26°, respectively, for GO and MPEG materials.

[0052] Example 2

[0053] Step 1, Preparation of graphene oxide dispersion

[0054] 100 mg of graphene oxide was dispersed in 50 mL of N,N-dimethylformamide, stirred, and then subjected to cell disruption for 60 min and ultrasonic treatment for 60 min to ensure that there was no obvious sedimentation and that a stable and uniform dispersion was formed.

[0055] Step 2: Grafting graphene sheets with polyethylene glycol monomethyl ether 1000 and polyethylene glycol monomethyl ether 5000.

[0056] Add 300 mg of polyethylene glycol monomethyl ether 1000 and 300 mg of polyethylene glycol monomethyl ether 5000 to the dispersion, stir for 30 min to ensure complete dissolution, then add 80 mg of diphenylmethane diisocyanate and 10 mg of dibutyltin dilaurate. The reaction system is heated to 60 °C under nitrogen atmosphere and refluxed for 6 h to induce esterification and complete the grafting reaction. Adjust the pH to 3 by adding hydrochloric acid dropwise, and wash the reaction mixture repeatedly with deionized water by centrifugation to remove excess reactants. Freeze-dry the resulting sample for 24 h to obtain the grafted product.

[0057] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0058] 100 mg of the grafted product was dispersed in 40 mL of distilled water and ultrasonically dispersed for 20 min to obtain a stable dispersion. 5 mL of xylene containing 20 mg of sodium dodecyl sulfate was mixed with the aqueous phase at an oil-to-water volume ratio of 1:8. The mixture was then stirred at high speed for 30 s using a homogenizer to form a stable O / W Pickering emulsion. This emulsion was rapidly frozen with liquid nitrogen for 0.5 h and then freeze-dried for 48 h to obtain phase change composite graphene oxide aerogel microspheres.

[0059] Example 3

[0060] Step 1, Preparation of graphene oxide dispersion

[0061] 100 mg of graphene oxide was dispersed in 50 mL of methanol, stirred, and then subjected to cell disruption for 60 min and ultrasonic treatment for 60 min to ensure that there was no obvious sedimentation and that a stable and uniform dispersion was formed.

[0062] Step 2: Grafting graphene sheets with polyethylene glycol 6000

[0063] Add 600 mg of polyethylene glycol 6000 to the dispersion and stir for 30 min until completely dissolved. Then add 80 mg of dicyclohexylcarbodiimide and 10 mg of N,N-dimethyl-4-aminopyridine. Heat the reaction system to 60 °C under nitrogen atmosphere and reflux for 6 h to induce esterification and complete the grafting reaction. Adjust the pH to 3 with hydrochloric acid dropwise, and wash the reaction mixture repeatedly with deionized water by centrifugation to remove excess reactants. Freeze-dry the resulting sample for 24 h to obtain the grafted product.

[0064] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0065] 100 mg of the grafted product was dispersed in 40 mL of distilled water and ultrasonically dispersed for 20 min to obtain a stable dispersion. 40 mL of xylene containing 20 mg of sodium dodecyl sulfate was mixed with the aqueous phase at an oil-to-water volume ratio of 1:1. The mixture was then stirred at high speed for 30 s using a homogenizer to form a stable O / W Pickering emulsion. This emulsion was rapidly frozen with liquid nitrogen for 0.5 h and then freeze-dried for 48 h to obtain phase change composite graphene oxide aerogel microspheres.

[0066] Example 4

[0067] Step 1, Preparation of graphene oxide dispersion

[0068] 100 mg of graphene oxide was dispersed in 50 mL of methanol, stirred, and then subjected to cell disruption for 60 min and ultrasonic treatment for 60 min to ensure that there was no obvious sedimentation and that a stable and uniform dispersion was formed.

[0069] Step 2, grafting graphene sheets with polyethylene glycol 1000

[0070] Add 600 mg of polyethylene glycol 1000 to the dispersion and stir for 30 min until completely dissolved. Then add 80 mg of triallyl isocyanurate and 10 mg of dibutyltin maleate. The reaction system is heated to 60 °C under nitrogen atmosphere and refluxed for 6 h to induce esterification and complete the grafting reaction. Adjust the pH to 3 by adding hydrochloric acid dropwise, and wash the reaction mixture repeatedly with deionized water by centrifugation to remove excess reactants. Freeze-dry the resulting sample for 24 h to obtain the grafted product.

[0071] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0072] 100 mg of the grafted product was dispersed in 40 mL of distilled water and ultrasonically dispersed for 20 min to obtain a stable dispersion. 10 mL of xylene containing 6 mg of Span 80 and 14 mg of Tween 80 was mixed with the aqueous phase at an oil-to-water volume ratio of 1:4. The mixture was stirred at high speed for 30 s using a homogenizer to form a stable O / W type Pickering emulsion. After rapid freezing with liquid nitrogen for 0.5 h, the emulsion was freeze-dried for 48 h to obtain phase change composite graphene oxide aerogel microspheres.

[0073] Example 5

[0074] Step 1, Preparation of graphene oxide dispersion

[0075] 100 mg of graphene oxide was dispersed in 50 mL of distilled water, stirred, and then subjected to cell disruption for 60 min and ultrasonic treatment for 60 min to ensure that there was no obvious sedimentation and that the dispersion was stable and uniform.

[0076] Step 2: Grafting graphene sheets with polyethylene glycol 6000 and polyethylene glycol monomethyl ether 2000

[0077] Add 400 mg of polyethylene glycol 6000 and 200 mg of polyethylene glycol monomethyl ether 2000 to the dispersion, stir for 30 min to ensure complete dissolution, then add 80 mg of dicyclohexylcarbodiimide and 10 mg of N,N-dimethyl-4-aminopyridine. The reaction system is heated to 60 °C under nitrogen atmosphere and refluxed for 6 h to induce esterification and complete the grafting reaction. Adjust the pH to 3 by adding hydrochloric acid dropwise, and wash the reaction mixture repeatedly with deionized water by centrifugation to remove excess reactants. Freeze-dry the resulting sample for 24 h to obtain the grafted product.

[0078] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0079] 100 mg of the grafted product was dispersed in 40 mL of distilled water and ultrasonically dispersed for 20 min to obtain a stable dispersion. 10 mL of xylene containing 20 mg of sodium dodecyl sulfate was mixed with the aqueous phase at an oil-to-water volume ratio of 1:4. The mixture was stirred at high speed for 30 s using a homogenizer to form a stable O / W type Pickering emulsion. The emulsion was then rapidly frozen with liquid nitrogen for 0.5 h and freeze-dried for 48 h to obtain phase change composite graphene oxide aerogel microspheres.

[0080] Example 6

[0081] Step 1, Preparation of graphene oxide dispersion

[0082] 100 mg of graphene oxide was dispersed in 50 mL of distilled water, stirred, and then subjected to cell disruption for 60 min and ultrasonic treatment for 60 min to ensure that there was no obvious sedimentation and that the dispersion was stable and uniform.

[0083] Step 2: Grafting graphene sheets with polyethylene glycol monomethyl ether 1000

[0084] Add 600 mg of polyethylene glycol monomethyl ether 1000 to the dispersion and stir for 30 min until completely dissolved. Then add 80 mg of dicyclohexylcarbodiimide and 10 mg of N,N-dimethyl-4-aminopyridine. Heat the reaction system to 60 °C under nitrogen atmosphere and reflux for 6 h to induce esterification and complete the grafting reaction. Adjust the pH to 3 with hydrochloric acid dropwise, and wash the reaction mixture repeatedly with deionized water by centrifugation to remove excess reactants. Freeze-dry the resulting sample for 24 h to obtain the grafted product.

[0085] Step 3: Preparation of phase change composite aerogel microspheres using the Pickering emulsion method

[0086] 100 mg of the grafted product was dispersed in 40 mL of distilled water and ultrasonically dispersed for 20 min to obtain a stable dispersion. 10 mL of toluene containing 20 mg of sodium dodecylbenzenesulfonate was mixed with the aqueous phase at an oil-to-water volume ratio of 1:4. The mixture was stirred at high speed for 30 s using a homogenizer to form a stable O / W type Pickering emulsion. After rapid freezing with liquid nitrogen for 0.5 h, the emulsion was freeze-dried for 48 h to obtain phase change composite graphene oxide aerogel microspheres.

[0087] The loosely folded phase change composite aerogel microspheres prepared through the above embodiments have a phase change temperature range of 30–80℃, a phase change enthalpy of 60–120 J / g, and a size of approximately 10–50 μm. Their size is controllable and easily dispersed in a matrix, meeting more practical application needs, broadening application scenarios, and making their application in micro-devices possible. This invention employs a method for preparing phase change composite graphene oxide aerogel microspheres and the resulting microspheres. Using graphene oxide as a thermally conductive framework and grafting phase change materials, the microspheres are composited via a solid-solid phase change process. They exhibit good enthalpy, excellent thermal cycling performance, low leakage of the phase change material, high thermal conductivity within the framework, ease of use, and flexible application. They possess significant potential for thermal energy storage and temperature management, and can be applied in precision thermal management applications such as batteries and electronic devices, thereby improving the safety of electronic products.

Claims

1. A method for preparing phase change composite graphene oxide aerogel microspheres, characterized in that, Includes the following steps: Step 1, Preparation of graphene oxide dispersion: Graphene oxide is placed in a solvent, stirred, and then subjected to cell pulverization and ultrasonic treatment to obtain a stable and uniform graphene oxide dispersion. Step 2, grafting phase change material onto graphene sheets: Add phase change material to graphene oxide dispersion, stir to dissolve completely, then add coupling agent and catalyst, and reflux the reaction system under nitrogen atmosphere for a certain time to undergo esterification reaction to complete grafting. After acid washing and freeze drying, the grafted product is obtained. Step 3, Preparation of phase change composite aerogel microspheres by Pickering emulsion method: The grafted product is placed in a solvent and ultrasonically dispersed to obtain a stable grafted product dispersion; the oil phase containing emulsifier is mixed with the grafted product dispersion and stirred at high speed to form a stable O / W type Pickering emulsion. After rapid freezing with liquid nitrogen, the microspheres with a loose folded structure are obtained by freeze drying, and the size of the microspheres is 10-50 μm.

2. The preparation method according to claim 1, characterized in that, The solvent is any one of distilled water, dimethylformamide, ethanol, and methanol.

3. The preparation method according to claim 1, characterized in that, In step 2, the phase change material is a single or compounded polyethylene glycol with a molecular weight range of 1000–6000, or / and Single or compounded polyethylene glycol monomethyl ethers with a molecular weight range of 1000 to 5000.

4. The preparation method according to claim 1, characterized in that, The coupling agent in step 2 is any one of dicyclohexylcarbodiimide, triallyl isocyanurate, and diphenylmethane diisocyanate.

5. The preparation method according to claim 1, characterized in that, The catalyst in step 2 is any one of dimethylaminopyridine, dibutyltin maleate, or dibutyltin dilaurate.

6. The preparation method according to claim 1, characterized in that, In step 3, the oil phase is any one of xylene, toluene, or benzene.

7. The preparation method according to claim 1, characterized in that, In step 3, the emulsifier is any one or more compound emulsifiers selected from sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, Span 80, and Tween 80.

8. The preparation method according to claim 1, characterized in that, In step 3, the oil-water volume ratio of the oil phase and water phase mixture is in the range of 1:1 to 1:

8.

9. A phase change composite graphene oxide aerogel microsphere, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.

10. An application of the phase change composite graphene oxide aerogel microspheres as described in claim 9, characterized in that, These aerogel microspheres are used for thermal management of batteries or electronic devices.

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