Intelligent energy management material and preparation method thereof

Abstract

The invention discloses an intelligent energy management material and a preparation method, the intelligent energy management material is aerogel-based composite PCMs, and the aerogel-based composite PCMs are selected from graphene / paraffin aerogel, graphene aerogel-paraffin phase change microspheres and MXene coated PEG aerogel. The prepared intelligent energy management material, namely the aerogel-based composite PCMs, is stable in form, enhanced in thermal conductivity, flexible and foldable, can be applied to wearable thermal sensors and thermal resistance clothes, and has wider application space.

Description

Technical Field

[0001] The invention relates to an intelligent energy management material and a preparation method thereof. Background Art

[0002] The rapid growth of fossil fuel demand and the low efficiency of energy utilization are common problems that restrict economic and industrial development. These problems can be solved by improving energy efficiency and saving energy. Thermal energy, as an important energy supply method closely related to social production and daily life, plays an important role. It can effectively alleviate the mismatch between thermal energy supply and demand, thereby improving energy utilization efficiency.

[0003] In recent years, phase change materials (PCMs) have shown significant advantages such as low cost and high efficiency. PCMs can alleviate the energy crisis and reduce environmental pollution. They are considered to be a potential method for efficient energy utilization and have broad application prospects. Since PCMs undergo phase changes, they are able to absorb or release a large amount of latent heat, and their temperature remains almost constant all the time. Among the numerous PCMs, the exploration of organic solid-liquid PCMs has attracted considerable attention. This high interest can be attributed to their noteworthy properties, including large latent heat capacity, consistent phase change temperature, minimal volume change, and reliable repeatability of storage and release properties. However, the inherent challenge of liquid phase leakage generated during the phase change process imposes significant limitations on the applicability of solid-liquid PCMs. This limitation, in turn, shortens their service life.

[0004] Currently, the encapsulation methods for PCMs are microencapsulation and nanoencapsulation. In microencapsulation, PCMs are confined within a shell made of organic, inorganic or polymeric materials. Nanoencapsulation, on the other hand, involves the infiltration of PCMs into porous structures (such as aerogels) to create a form-stable structure. Both methods offer a general solution to manage thermal energy storage while maintaining high thermal storage performance. Aerogels are a class of synthetic porous ultra-lightweight materials derived from gels. For the manufacture of aerogels, the liquid component in the gel is replaced by a gas while maintaining a dry structure without significantly disrupting the spatial network. Aerogels have the advantages of extremely high porosity, large specific surface area and ultra-low density, and have been widely used in aerospace engineering, energy harvesting, energy storage, tissue engineering and environmental remediation. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an intelligent energy management material, wherein the "intelligent energy management material" is an aerogel-based composite PCMs, which has a stable form and enhanced thermal conductivity and has good application prospects in thermal management systems.

[0006] The specific technical solution adopted by the present invention is:

[0007] A smart energy management material, wherein the smart energy management material is an aerogel-based composite PCMs, and the aerogel-based composite PCMs is selected from graphene / paraffin aerogel, graphene aerogel-paraffin phase change microspheres and MXene@PEG aerogel.

[0008] Furthermore, the preparation method of the graphene / paraffin aerogel is as follows: mixing an aqueous solution of graphene oxide with a cyclohexane paraffin solution, and shaking vigorously to form a uniform graphene oxide / paraffin emulsion; sealing the graphene oxide / paraffin emulsion in an autoclave, heating at high temperature to obtain a graphene gel containing cyclohexane / paraffin droplets, cooling to room temperature, and then immersing the graphene gel in deionized water to evaporate the cyclohexane to obtain a graphene / paraffin hydrogel, and drying the obtained graphene / paraffin hydrogel to obtain a graphene / paraffin aerogel.

[0009] More preferably, the concentration of the graphene oxide aqueous solution is 5 mg / mL, the concentration of the cyclohexane paraffin solution is 50-200 mg / mL, and the volume ratio of the graphene oxide aqueous solution to the cyclohexane paraffin solution is: 20-25:15-20.

[0010] More preferably, the graphene oxide / paraffin emulsion is sealed in an autoclave and heated at 150-180° C. for 13-16 hours to obtain a graphene gel containing cyclohexane / paraffin droplets.

[0011] More preferably, the graphene gel is immersed in deionized water at 85-95° C. for 40-60 min to evaporate the cyclohexane to obtain the graphene / paraffin hydrogel.

[0012] Furthermore, the preparation method of the graphene aerogel-paraffin phase change microspheres is as follows: graphene hydrogel microspheres are prepared by a jetting method, and after exchanging the solvent with anhydrous ethanol, the graphene aerogel microspheres are dried to obtain graphene aerogel microspheres, and after argon treatment, the graphene aerogel microspheres and paraffin are heated and kept warm to inject the graphene aerogel microspheres into the paraffin; finally, the liquid phase is filtered, and the residue is transferred to a hot plate with a filter to absorb excess paraffin, and the graphene aerogel-paraffin phase change microspheres are cooled at room temperature to obtain graphene aerogel-paraffin phase change microspheres.

[0013] More preferably, after treating in argon at 500-700° C. for 2-4 hours, the graphene aerogel microspheres and paraffin are heated to 60-80° C. and kept warm for 2-3 hours to inject the graphene aerogel microspheres into the paraffin.

[0014] More preferably, the liquid phase is filtered at 60-70°C.

[0015] Furthermore, the preparation method of the MXene@PEG aerogel is as follows: stirring and mixing a PEG (polyethylene glycol) solution and a MXene colloid (17.6 mg / mL) in a glass container to obtain a binary MXene@PEG dispersion; sealing the MXene@PEG dispersion, stirring and heating to obtain a uniform MXene@PEG dispersion; freeze-drying the uniform MXene@PEG dispersion to completely remove the solvent in the MXene@PEG dispersion to obtain a MXene@PEG aerogel.

[0016] More preferably, the concentration of the PEG solution is 150 mg / mL, and the concentration of the MXene colloid is 17.6 mg / mL.

[0017] More preferably, the MXene@PEG dispersion is sealed and heated at 70° C. for 24 h with stirring to obtain a uniform dispersion.

[0018] More preferably, the uniform MXene@PEG dispersion is freeze-dried for 56 h to completely remove the solvent in the MXene@PEG dispersion to obtain a MXene@PEG aerogel.

[0019] The beneficial effects of the present invention are as follows: the intelligent energy management material prepared by the present invention, namely aerogel-based composite PCMs, is not only stable in form and has enhanced thermal conductivity, but is also flexible and foldable, and can be applied to wearable thermal sensors and thermal resistance clothing, and has a wider application space. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1-3 Shown is the flexibility test result of the graphene aerogel-paraffin phase change microsphere RSAM prepared in Example 2;

[0021] Figure 4 The product picture of graphene aerogel-paraffin phase change microsphere RSAM prepared in Example 2 is shown;

[0022] Figure 5 Shown are the mechanical properties of the graphene aerogel-paraffin phase change microspheres RSAM prepared in Example 2. DETAILED DESCRIPTION

[0023] Now describe in detail various exemplary embodiments of the present invention, this detailed description should not be considered as limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing a particular embodiment, and are not used to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the range.

[0024] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0025] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0026] Example 1

[0027] 20 mL of graphene oxide aqueous solution (5 mg / mL) was mixed with 15 mL of cyclohexane paraffin solution (50-200 mg / mL), and then shaken vigorously to form a uniform graphene oxide / paraffin emulsion. The emulsion was sealed in an autoclave and heated at 160°C for 15 hours to obtain a graphene gel containing cyclohexane / paraffin droplets. After cooling to room temperature, the gel was soaked in deionized water at 90°C for 1 hour to evaporate the cyclohexane. The obtained graphene / paraffin hydrogel was freeze-dried to finally obtain a graphene / paraffin aerogel.

[0028] The graphene / paraffin aerogel prepared in this embodiment has a thermal conductivity that is 32% higher than that of pure paraffin (measured by a high-precision thermal conductivity tester), and a paraffin encapsulation rate of 97% (measured by an ultrafiltration membrane filtration method).

[0029] Example 2

[0030] First, graphene hydrogel microspheres were prepared by the injection method. After exchanging the solvent with anhydrous ethanol for 1 week, graphene aerogel microspheres were obtained after CO2 supercritical drying. Then, the graphene aerogel microspheres were treated in argon at 600°C for 3 hours. The graphene aerogel microspheres and paraffin were heated to 80°C in an oven (higher than the melting point of paraffin 48°C) and kept warm for 2 hours to inject paraffin into the graphene aerogel microspheres. Finally, the liquid phase was filtered at 65°C, and the residue was transferred to a hot plate with a filter to absorb excess paraffin. Cooling at room temperature gave graphene aerogel-paraffin phase change microspheres. The obtained graphene aerogel-paraffin phase change microspheres were subjected to flexibility test ( Figure 1-3 ) and fold ( Figure 4 ), it can be seen that it has good flexibility and foldability. The mechanical test of the prepared graphene aerogel-paraffin phase change microspheres is carried out, and the test results are as follows Figure 5 (a) 5-point test device method for spherical materials. (b) Compression curves of PSAM and ASAM. (c) Expanded linear area of ​​compression curve obtained by VD method. (d) Compression curve and expanded linear area of ​​SCD method

[0031] ). It can be seen that the prepared graphene aerogel-paraffin phase change microspheres have good mechanical properties.

[0032] Example 3

[0033] The MXene skeleton is considered to be a photothermal agent with a high extinction coefficient in the UV-Vis-NIR region. The PEG solution (150 mg / mL) and the MXene colloid (17.6 mg / mL) were stirred and mixed in a glass container at a volume ratio of 3:7 to obtain a binary MXene@PEG dispersion. Then, the MXene@PEG dispersion was sealed and heated at 70°C with stirring for 24 hours to obtain a uniform dispersion. After freeze drying for 56 hours, the solvent in the MXene@PEG dispersion was completely removed to obtain a MXene@PEG aerogel.

[0034] The photothermal conversion efficiency of the MXene@PEG aerogel prepared in this embodiment is as high as 92.5% (detected by laser irradiation method and laser power meter method).

[0035] Although the above embodiments have been described, once those skilled in the art know the basic creative concepts, they can make additional changes and modifications to these embodiments. Therefore, the above description is only an embodiment of the present invention and does not limit the patent protection scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A smart energy management material, characterized in that: The smart energy management material is an aerogel-based composite PCMs, and the aerogel-based composite PCMs is selected from graphene / paraffin aerogel, graphene aerogel-paraffin phase change microspheres and MXene@PEG aerogel.

2. The intelligent energy management material according to claim 1, characterized in that: The preparation method of the graphene / paraffin aerogel comprises the following steps: mixing a graphene oxide aqueous solution with a cyclohexane paraffin solution, and shaking vigorously to form a uniform graphene oxide / paraffin emulsion; sealing the graphene oxide / paraffin emulsion in an autoclave, heating at high temperature to obtain a graphene gel containing cyclohexane / paraffin droplets, cooling to room temperature, soaking the graphene gel in deionized water to evaporate the cyclohexane to obtain a graphene / paraffin hydrogel, and drying the obtained graphene / paraffin hydrogel to obtain a graphene / paraffin aerogel.

3. The intelligent energy management material according to claim 2, characterized in that: The concentration of the graphene oxide aqueous solution is 5 mg / mL, the concentration of the cyclohexane paraffin solution is 50-200 mg / mL, and the volume ratio of the graphene oxide aqueous solution to the cyclohexane paraffin solution is: 20-25:15-20; and / or, The graphene oxide / paraffin emulsion is sealed in an autoclave and heated at 150-180° C. for 13-16 hours to obtain a graphene gel containing cyclohexane / paraffin droplets; and / or, The graphene gel is immersed in deionized water at 85-95° C. for 40-60 min to evaporate the cyclohexane to obtain the graphene / paraffin hydrogel.

4. The intelligent energy management material according to claim 1, characterized in that: The preparation method of the graphene aerogel-paraffin phase change microspheres is as follows: preparing graphene hydrogel microspheres by a jetting method, exchanging the solvent with anhydrous ethanol, drying to obtain graphene aerogel microspheres, heating and insulating the graphene aerogel microspheres and paraffin after argon treatment, so that the graphene aerogel microspheres are injected into the paraffin; finally, filtering the liquid phase, transferring the residue to a hot plate with a filter to absorb excess paraffin, and cooling at room temperature to obtain the graphene aerogel-paraffin phase change microspheres.

5. The intelligent energy management material according to claim 4, characterized in that: After treating in argon at 500-700°C for 2-4 hours, heating the graphene aerogel microspheres and paraffin to 60-80°C and keeping the temperature for 2-3 hours to inject the graphene aerogel microspheres into the paraffin; and / or, The liquid phase was filtered at 60-70°C.

6. The intelligent energy management material according to claim 1, characterized in that: The preparation method of the MXene@PEG aerogel is as follows: PEG (polyethylene glycol) solution and MXene colloid (17.6 mg / mL) are stirred and mixed in a glass container to obtain a binary MXene@PEG dispersion; the MXene@PEG dispersion is sealed, stirred and heated to obtain a uniform MXene@PEG dispersion; the uniform MXene@PEG dispersion is freeze-dried to completely remove the solvent in the MXene@PEG dispersion to obtain a MXene@PEG aerogel.

7. The intelligent energy management material according to claim 6, characterized in that: The concentration of the PEG solution is 150 mg / mL, and the concentration of the MXene colloid is 17.6 mg / mL; and / or, The MXene@PEG dispersion was sealed and heated at 70°C for 24 h with stirring to obtain a uniform dispersion; and / or, After freeze-drying the uniform MXene@PEG dispersion for 56 h, the solvent in the MXene@PEG dispersion was completely removed to obtain MXene@PEG aerogel.

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