Thermal insulation-thermal conduction integrated phase change composite material and preparation method thereof

Abstract

The present application relates to the technical field of phase change energy storage and heat management, and provides a heat insulation-heat conduction integrated phase change composite material and a preparation method thereof.The preparation method comprises the following steps: S1, preparing a heat conduction layer precursor mixed slurry;S2, preparing a heat insulation layer precursor mixed solution;S3, pouring the two solutions into a customized mold respectively, directional freezing, freeze-drying;S4, thermal imination;S5, partially immersing a phase change material, and encapsulating the phase change material in the skeleton of the heat conduction layer aerogel by using a physical adsorption method.By introducing a calcium ion regulator into the heat insulation layer precursor solution, the pore size structure of the polyimide aerogel can be regulated, and the heat insulation layer and the heat conduction layer can be connected as a "bridge", so that the integrated design of the material is realized.

Description

Technical Field

[0001] This invention relates to the field of phase change energy storage and thermal management technology, and in particular to a thermal insulation-thermal conduction integrated phase change composite material and its preparation method. Background Technology

[0002] Phase change latent heat storage technology, with its highly efficient latent heat storage capacity, has shown great application potential in fields such as building energy conservation and solar energy utilization. This technology achieves energy storage and release through the release or absorption of latent heat during the phase change process of matter. To improve the system's thermal conductivity, researchers have designed directional heat-conducting structures, enhancing thermal conductivity by optimizing the heat flow path. However, while this design improves thermal conductivity in the short term, it also accelerates heat transfer, leading to rapid release of stored heat. This contradicts the requirements of continuous heating in the building sector and the need for electronic components to withstand transient heat pulses.

[0003] To address this contradiction, a composite structure design combining a high thermal conductivity phase change layer and a low thermal conductivity aerogel layer was proposed. This design aims to rapidly absorb and release heat through the high thermal conductivity phase change material, while simultaneously utilizing the low thermal conductivity aerogel layer to mitigate heat loss, thus achieving long-term heat retention. However, this composite material suffers from insufficient interfacial bonding strength in practical applications, leading to cracking during use and affecting the material's stability and lifespan. Therefore, achieving the integration of the high thermal conductivity phase change layer and the low thermal conductivity aerogel layer structure has become a key technical challenge for improving the performance of phase change latent thermal energy storage systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an integrated thermal insulation and thermal conduction phase change composite material and its preparation method, which solves the problem that there is no integrated special material in the prior art that has the functions of thermal conduction, thermal storage and thermal insulation at the same time.

[0005] The present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a method for preparing an integrated thermal insulation and thermal conductivity phase change composite material, comprising:

[0007] S1. Dissolve the thickener and thermally conductive filler in an aqueous cellulose solution to obtain a thermally conductive layer precursor mixture slurry;

[0008] S2. Dissolve the heat insulation layer polymer, nanofibers, inorganic nanofillers and calcium ion regulator in water and mix them evenly to obtain a heat insulation layer precursor mixture.

[0009] S3. The heat-conducting layer precursor mixture and the heat insulation layer precursor mixture are poured into a custom mold in sequence, and then frozen and freeze-dried with liquid nitrogen to obtain an aerosol.

[0010] S4. The freeze-dried aerosol is thermally imidized.

[0011] S5. Immerse the thermally conductive layer of the product after thermal imidization into molten phase change material, partially impregnate it with phase change material, and encapsulate the phase change material in the framework of the thermally conductive layer aerogel using a physical adsorption method to obtain the integrated thermal insulation-thermal conduction phase change composite material.

[0012] In addition to any of the possible implementations described above, another implementation is provided in which, in step S1, the concentration of the cellulose aqueous solution is 1 to 10 mg / mL, and the mass ratio of the thickener to the thermally conductive filler is 200:(50 to 1000).

[0013] The above parameter range represents the optimal range that balances the thermal conductivity of the thermally conductive layer with the viscosity of the precursor solution. When the parameter is below the lower limit, insufficient addition of thermally conductive filler results in a negligible increase in the thermal conductivity of the thermally conductive layer, failing to meet the requirements for efficient storage and release of thermal energy during application. When the parameter is above the upper limit, the viscosity of the precursor solution decreases significantly, failing to ensure that the insulation layer solution floats on top of the thermally conductive layer solution before the directional freezing process, thus preventing stratification.

[0014] In addition to any of the possible implementations described above, another implementation is provided in which, in step S2, the mass ratio of the added heat insulation layer polymer to nanofibers is 600:(10-200), the mass ratio of the added heat insulation layer polymer to nanofiller is 600:(10-200), the concentration of calcium ion regulator is 0.1mol / L, and the added amount is 0.2-5mL.

[0015] The aforementioned parameter range represents the optimal balance between the shrinkage resistance and thermal conductivity of the insulation layer aerogel. When the mass ratio of the insulation layer polymer to nanofibers / nanofillers is below the lower limit, insufficient addition of nanofillers and nanofibers leads to severe skeletal shrinkage of the polyimide aerogel during freeze-drying and thermal imidization, significantly reducing the aerogel's insulation performance. Conversely, when the parameters exceed the upper limit, excessive addition of nanofillers results in a significant increase in the thermal conductivity of the polyimide aerogel, further reducing its insulation performance.

[0016] In addition to any of the possible implementations described above, another implementation is provided in which, in step S3, the heat-conducting layer precursor mixture is first poured into a custom mold, and then the heat insulation layer precursor mixture is slowly poured onto the top of the heat-conducting layer precursor mixture. After standing for a certain period of time, liquid nitrogen is used for directional freezing.

[0017] In addition to any of the possible implementations described above, another implementation is provided in which the thermal imidization conditions in step S4 are: under a nitrogen atmosphere, holding at 200°C for 1–2 hours, holding at 300°C for 1–4 hours, with a heating rate of 3–6°C.

[0018] / min.

[0019] In addition to any of the possible implementations described above, another implementation is provided in which, in step S5, the mass and adsorption time of the molten phase change material are controlled to achieve that the heat-conducting layer is fully impregnated with the phase change material, while the heat insulation layer has zero adsorption of the phase change material.

[0020] In addition to any of the possible implementations described above, another implementation is provided in which, in step S1, the thickener is sodium alginate, and the thermally conductive filler is any one of single-walled carbon nanotubes, carbon fibers, graphene nanosheets, graphene oxide (GO), reduced graphene oxide, MXene, expanded graphite, aluminum nitride, and boron nitride.

[0021] In addition to any of the possible implementations described above, a further implementation is provided in which, in step S2, the heat insulation layer polymer is polyimide (PAA), the nanofibers are any one of aramid nanofibers, carboxymethyl cellulose, cellulose nanofibers, microcrystalline cellulose, cellulose nanocrystals, and cellulose nanonets, the inorganic nanofiller is any one of nano silica, graphene oxide, carbon nanotubes, nano clay, nano alumina, nano aluminum hydroxide, nano zirconium oxide, nano zinc borate, nano titanium dioxide, and nano silicates, and the calcium ion regulator is any one of an aqueous solution of calcium fluoride, calcium chloride, calcium bromide, calcium nitrate, and calcium acetate.

[0022] In step S4, the purpose of thermal imidization is to dehydrate and cyclize PAA to form an imidized structure, transforming it into a polyimide (PI) aerogel with higher thermal stability and thermal insulation properties. The thermal imidization process not only enhances the rigidity of the molecular chain but also eliminates residual solvent molecules within the chain segments.

[0023] In addition to any of the possible implementations described above, another implementation is provided in which, in step S5, the calcium ion regulator is any one of the aqueous solutions of calcium fluoride, calcium chloride, calcium bromide, calcium nitrate, and calcium acetate.

[0024] On the other hand, the present invention also provides a thermal insulation-thermal conduction integrated phase change composite material, which is obtained by the above-described preparation method.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. This invention relates to a method for preparing phase change composite materials. For the aerogel insulation layer, it utilizes horizontal directional freezing technology and the addition of calcium ions for structural control, achieving horizontal skeleton orientation and improving the material's thermal insulation performance in the vertical direction. For the phase change thermally conductive layer, it adds thermally conductive fillers to construct vertical thermally conductive channels through vertical directional freezing, thereby enhancing its thermal conductivity. The final result is an integrated thermal insulation-thermal storage phase change composite material with excellent thermal conductivity, thermal storage performance, and thermal insulation properties.

[0027] 2. The phase change composite material produced by this invention has advantages such as high heat storage density, high thermal stability, and long temperature control time. The insulation layer and the thermally conductive layer adopt an orthogonal orientation design, achieving rapid heat storage while delaying heat transfer. This phase change composite material can rapidly absorb / release heat energy on the surface of the object under thermal management and largely isolate heat transfer. For building energy-saving temperature control or electronic component thermal management, it can achieve instantaneous heat storage and accumulation, improving the continuity and reliability of the thermal management process. Attached Figure Description

[0028] Figure 1 : Front view (a) and top view (b) of the customized freezing mold in the embodiment of the present invention.

[0029] Figure 2 Scanning electron microscope images of the thermally conductive layer (a), the thermal insulation layer (b), and the interface (c) of the two layers obtained in Example 1.

[0030] Figure 3 Scanning electron microscope (SEM) images of the thermally conductive layer (a), the thermal insulation layer (b), and the interface (c) of the two layers of the integrated thermal insulation-thermal conduction aerogel obtained in Example 2.

[0031] Figure 4 Scanning electron microscope images of phase transition layers obtained in Examples 1(a) and 2(b).

[0032] Figure 5 Example 1: Melting and solidification curves and enthalpy values ​​of materials at the bottom, middle, and interface of the phase change layer and the middle of the insulation layer.

[0033] Figure 6 Example 1: Melting and solidification curves and enthalpy values ​​of materials at the bottom, middle, and interface of the phase change layer and the middle of the insulation layer.

[0034] Figure 7 The diagram shown is a schematic flow chart of a method for preparing an integrated thermal insulation and thermal conductivity phase change composite material according to an embodiment of the present invention. Detailed Implementation

[0035] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered in isolation, but can be combined with each other to achieve better technical effects.

[0036] An embodiment of the present invention provides a method for preparing an integrated thermal insulation and thermal conductivity phase change composite material, comprising:

[0037] S1. Dissolve the thickener and thermally conductive filler in an aqueous cellulose solution to obtain a thermally conductive layer precursor mixture slurry;

[0038] S2. Dissolve the heat insulation layer polymer, nanofibers, inorganic nanofillers and calcium ion regulator in water and mix them evenly to obtain a heat insulation layer precursor mixture.

[0039] S3. The heat-conducting layer precursor mixture and the heat insulation layer precursor mixture are poured into a custom mold in sequence, and then frozen and freeze-dried with liquid nitrogen to obtain an aerosol.

[0040] S4. The freeze-dried aerosol is thermally imidized.

[0041] S5. Immerse the thermally conductive layer of the product after thermal imidization into molten phase change material, partially impregnate it with phase change material, and encapsulate the phase change material in the framework of the thermally conductive layer aerogel using a physical adsorption method to obtain the integrated thermal insulation-thermal conduction phase change composite material.

[0042] The specific process is as follows: Figure 7 As shown.

[0043] In one specific embodiment, in step S1, the concentration of the cellulose aqueous solution is 1-10 mg / mL, and the ratio of thickener to thermally conductive filler is 200:(50-1000).

[0044] In one specific embodiment, in step S2, the mass ratio of the added thermal insulation layer polymer to the nanofibers is 600:

[0045] The mass ratio of the added heat insulation layer polymer to the nanofiller is 600:(10-200), the concentration of calcium ion regulator is 0.1mol / L, and the addition amount is 0.2-5mL.

[0046] In one specific embodiment, in step S3, the heat-conducting layer precursor mixture is first poured into a custom mold, and then the heat insulation layer precursor mixture is slowly poured onto the top of the heat-conducting layer precursor mixture. After standing for a certain period of time, liquid nitrogen is used for directional freezing.

[0047] In one specific embodiment, in step S4, the conditions for thermal imidization are: under a nitrogen atmosphere, holding at 200°C for 1-2 hours, holding at 300°C for 1-4 hours, with a heating rate of 3-6°C / min.

[0048] In one specific embodiment, in step S5, the mass and adsorption time of the molten phase change material are controlled to achieve that the heat-conducting layer is fully impregnated with the phase change material, while the heat insulation layer has zero adsorption of the phase change material.

[0049] In one specific embodiment, in step S1, the thickener is sodium alginate, and the thermally conductive filler is any one of single-walled carbon nanotubes, carbon fibers, graphene nanosheets, graphene oxide (GO), reduced graphene oxide, MXene, expanded graphite, aluminum nitride, and boron nitride.

[0050] In one specific embodiment, in step S2, the heat insulation layer polymer is polyimide (PAA), the nanofibers are any one of aramid nanofibers, carboxymethyl cellulose, cellulose nanofibers, microcrystalline cellulose, cellulose nanocrystals, and cellulose nanonets, the inorganic nanofiller is any one of nano silica, graphene oxide, carbon nanotubes, nano clay, nano alumina, nano aluminum hydroxide, nano zirconium oxide, nano zinc borate, nano titanium dioxide, and nano silicates, and the calcium ion regulator is any one of calcium fluoride, calcium chloride, calcium bromide, calcium nitrate, and calcium acetate aqueous solution.

[0051] In one specific embodiment, in step S5, the calcium ion regulator is any one of the aqueous solutions of calcium fluoride, calcium chloride, calcium bromide, calcium nitrate, and calcium acetate.

[0052] This invention relates to an integrated thermal insulation and thermal conductivity phase change composite material, which is obtained by the preparation method described above.

[0053] Unless otherwise specified, all reagents used in the following examples were commercially available and were not subjected to additional purification.

[0054] PAA preparation: Weigh 4.95 g of 4,4'-diaminodiphenyl ether (ODA) and dissolve it in 90 mL of N,N-dimethylacetamide (DMAc). Then add 5.48 g of pyromellitic dianhydride (PMDA) and stir in an ice-water bath for 3 h at a speed of 600 rpm to obtain a linear PAA solution. Wash with acetone, dry and remove excess solvent to obtain solid PAA.

[0055] Example 1

[0056] 1) Weigh 0.6g PAA and dissolve it in 14mL of water, then add 0.4mL of triethylamine and stir vigorously to obtain a clear PAA solution; weigh 0.2g sodium alginate and 0.1g GO and add them to 25mL of 2mg / mL cellulose nanofiber aqueous solution, and stir thoroughly until homogeneous to obtain thermally conductive layer precursor solution A;

[0057] 2) Measure 10 mL of 2 mg / mL cellulose nanofiber aqueous solution and add it to PAA solution. Stir for 3 h, then add 1 mL of 0.1 mol / L calcium chloride aqueous solution and stir for 0.5 h to obtain thermal insulation layer precursor solution B;

[0058] 3) Pour solution A into a custom mold, slowly pour solution B onto the top of solution A, use liquid nitrogen for directional freezing, and then freeze-dry for 72 hours to obtain thermal insulation-thermal conduction integrated aerogel (PAA-GO);

[0059] 4) The aerogel was placed in a nitrogen atmosphere and kept at 200°C for 1 hour and 300°C for 2 hours. The heating rate was 5°C / min. PAA was thermally imidized to obtain polyimide (PI).

[0060] 5) Weigh 5g of polyethylene glycol 6000 and 10g of ethanol and mix them together to melt. Place the PI-based thermal insulation-thermal conduction integrated aerogel into the melted phase change material and let it stand for 10 minutes to allow the thermally conductive phase change layer to fully adsorb the phase change core material. Wipe away the excess phase change material with filter paper to obtain the thermal insulation-thermal conduction integrated phase change composite material PI-GO / PEG.

[0061] Figure 1 For the custom mold, the bottom is made of brass blocks, the lower part is made of polytetrafluoroethylene (PTFE), and the upper part is composed of both brass blocks and PTFE. Before formal freezing, the upper brass blocks were pre-cooled in liquid nitrogen. Then, the precursor solutions for the thermally conductive and insulating layers were poured into the mold and frozen using liquid nitrogen. Because the thermal conductivity of brass is significantly higher than that of PTFE, ice crystals in the precursor solutions first nucleated on the three brass blocks and grew along the temperature gradient. Specifically, the ice crystals in the thermally conductive layer grew vertically, while those in the insulating layer grew horizontally. During freezing, the oriented structure was aligned. Finally, after freeze-drying, the ice crystals sublimated, leaving behind the oriented thermally conductive / insulating framework.

[0062] Figure 2 The images show scanning electron microscope (SEM) images of various regions of the PI-GO aerogel, a phase change composite material carrier, in this embodiment. The thermally conductive layer exhibits a vertically oriented structure, while the thermally insulating layer exhibits a horizontally oriented structure. Two mutually perpendicularly oriented structures are observed at the interface between the thermally insulating layer and the thermally conductive layer.

[0063] Figure 4Image (a) is a scanning electron microscope image of the phase change layer of the PI-GO / PEG phase change composite material in this embodiment, wherein the skeleton is fully loaded with phase change material.

[0064] Figure 5 The melting and solidification curves of the PI-GO / PEG phase change composite material in this embodiment are shown. It was observed that in the phase change layer, the phase change enthalpy gradually decreases with increasing height, while in the insulation layer, there is almost no phase change material.

[0065] Example 2

[0066] 1) Weigh 0.6g PAA and dissolve it in 14mL of water, then add 0.4mL of triethylamine and stir vigorously to obtain a clear PAA solution; weigh 0.2g sodium alginate and 0.1g GO and add them to 25mL of 2mg / mL aramid nanofiber aqueous solution, and stir thoroughly until homogeneous to obtain thermally conductive layer precursor solution A;

[0067] 2) Measure 10 mL of 2 mg / mL aramid nanofiber aqueous solution and add it to PAA solution. Stir for 3 h, then add 1 mL of 0.1 mol / L calcium chloride aqueous solution and stir for 0.5 h to obtain heat insulation layer precursor solution B;

[0068] 3) Pour solution A into a custom mold, slowly pour solution B onto the top of solution A, use liquid nitrogen for directional freezing, and then freeze-dry for 72 hours to obtain thermal insulation-thermal conduction integrated aerogel (PAA-GO);

[0069] 4) The aerogel was placed in a nitrogen atmosphere and kept at 200°C for 1 hour and 300°C for 2 hours. The heating rate was 5°C / min. PAA was thermally imidized to obtain polyimide (PI).

[0070] 5) Weigh 5g of polyethylene glycol 6000 and 10g of ethanol and mix them together to melt. Place the PI-based thermal insulation-thermal conduction integrated aerogel into the melted phase change material and let it stand for 10 minutes to allow the thermally conductive phase change layer to fully adsorb the phase change core material. Wipe away the excess phase change material with filter paper to obtain the thermal insulation-thermal conduction integrated phase change composite material PI-GO / PEG.

[0071] Figure 3 The images show scanning electron microscope (SEM) images of various regions of the PI-GO aerogel, a phase change composite material carrier, in this embodiment. The thermally conductive layer exhibits a vertically oriented structure, while the thermally insulating layer exhibits a horizontally oriented structure. Two mutually perpendicularly oriented structures are observed at the interface between the thermally insulating layer and the thermally conductive layer.

[0072] Figure 4 Image (b) is a scanning electron microscope image of the phase change layer of the PI-GO / PEG phase change composite material in this embodiment, wherein the skeleton is fully loaded with phase change material.

[0073] Figure 6 The melting and solidification curves of the PI-GO / PEG phase change composite material in this embodiment are shown. It was observed that in the phase change layer, the phase change enthalpy gradually decreases with increasing height, while in the insulation layer, there is almost no phase change material.

[0074] The thermal insulation-thermal conduction integrated phase change composite material provided by this invention has excellent mechanical and functional stability, and excellent thermal insulation, thermal conduction and thermal storage performance.

[0075] This invention utilizes calcium ions to influence the structure through charge interactions with polyimide acid segments. These polyimide acid segments contain a large number of carboxylate groups (-COO). - ), calcium ions tend to react with -COO after addition. - Charge interactions occur, and calcium ions, exhibiting a positively charged divalent state, can connect end-to-end with two atoms containing -COO. - The polyimide acid segments make the polymer segments more tightly connected, resulting in smaller pore sizes and a higher specific surface area, which can reduce the thermal conductivity of the insulation layer. Similarly, the main component of the thermally conductive layer precursor solution is sodium alginate, which also contains a large number of carboxylate ions (-COO) in its structure. - Calcium ions can act as a bridge, connecting the polymer segments in the insulation layer with the sodium alginate that forms the framework of the thermally conductive layer, ultimately achieving integrated fabrication of the insulation and thermally conductive frameworks. Without calcium ions, there is no strong interaction between the insulation and thermally conductive layers, making it prone to structural separation during application.

[0076] The polyimide aerogel used in this invention undergoes cross-linking with doped calcium ions, resulting in a rich and tunable porous structure. Furthermore, through orientation, the polyimide aerogel achieves a horizontal orientation at the microscopic level, orthogonal to the heat transfer direction, thus blocking heat exchange. The polyimide aerogel possesses excellent flame retardancy, and its mechanical properties are enhanced through structural adjustments, exhibiting good thermal insulation and thermal stability.

[0077] The phase change composite material provided by this invention has a high degree of integration. The gelation effect of sodium alginate and calcium ions enhances the stability of the thermal conductive layer. The vertically oriented thermal conductive layer and the horizontally oriented thermal insulation layer achieve interfacial connection through calcium ion crosslinking.

[0078] While several embodiments of the present invention have been provided herein, those skilled in the art should understand that modifications can be made to these embodiments without departing from the spirit of the invention. The above embodiments are merely exemplary and should not be construed as limiting the scope of the invention.

Claims

1. A method for preparing a heat-insulation and heat-conduction integrated phase change composite material, characterized in that, The preparation method comprises: S1, dissolving a thickening agent and a heat-conducting filler in a cellulose aqueous solution to obtain a heat-conducting layer precursor mixed slurry; the thickening agent is sodium alginate; S2, dissolving a heat-insulating layer polymer, nanofiber, inorganic nanofiller and calcium ion regulator in water and mixing uniformly to obtain a heat-insulating layer precursor mixed solution; the heat-insulating layer polymer is polyamide acid; S3, pouring the heat-conducting layer precursor mixed slurry and the heat-insulating layer precursor mixed solution into a customized mold in sequence, directional freezing with liquid nitrogen and freeze-drying to obtain an aerosol; S4, heat imidizing the freeze-dried aerosol; S5, immersing the heat-conducting layer of the heat imidized product in a molten phase change material, partially impregnating the phase change material, and encapsulating the phase change material in the skeleton of the heat-conducting layer aerogel by a physical adsorption method to obtain the heat-insulating and heat-conducting integrated phase change composite material.

2. The preparation method of the integrated thermal insulation and thermal conductivity phase change composite material as described in claim 1, characterized in that, In step S1, the concentration of the cellulose aqueous solution is 1-10 mg / mL, and the mass ratio of the added amount of the thickening agent to the heat-conducting filler is 200: (50-1000).

3. The method for preparing the integrated thermal insulation and thermal conductivity phase change composite material as described in claim 1, characterized in that, In step S2, the mass ratio of the added amount of the heat-insulating layer polymer to the nanofiber is 600: (10-200), the mass ratio of the added amount of the heat-insulating layer polymer to the nanofiller is 600: (10-200), the concentration of the calcium ion regulator is 0.1 mol / L, and the added amount is 0.2-5 mL.

4. The preparation method of the integrated thermal insulation and thermal conductivity phase change composite material as described in claim 1, characterized in that, In step S3, the heat-conducting layer precursor mixed slurry is poured into the customized mold first, and then the heat-insulating layer precursor mixed solution is slowly poured onto the upper part of the heat-conducting layer precursor mixed slurry, and directional freezing with liquid nitrogen is performed after standing for a certain period of time.

5. The method for preparing the integrated thermal insulation and thermal conductivity phase change composite material as described in claim 1, characterized in that, In step S4, the heat imidization conditions are as follows: under a nitrogen atmosphere, 200℃ for 1-2 h, 300℃ for 1-4 h, and the heating rate is 3-6 ℃ / min.

6. The method for preparing the integrated thermal insulation and thermal conductivity phase change composite material as described in claim 1, characterized in that, In step S5, the mass of the molten phase change material and the adsorption time are regulated to realize full impregnation of the phase change material in the heat-conducting layer, and zero adsorption of the phase change material in the heat-insulating layer.

7. The method for preparing the integrated thermal insulation and thermal conductivity phase change composite material as described in claim 1, characterized in that, In step S1, the heat-conducting filler is any one of single-walled carbon nanotubes, carbon fibers, graphene nanosheets, graphene oxide, reduced graphene oxide, MXene, expanded graphite, aluminum nitride and boron nitride.

8. The method of claim 1, wherein the integrated thermal storage-heat conducting phase change composite is prepared by the steps of: a) mixing the phase change material with the heat conducting material; b) mixing the mixture of step a) with the heat storage material; and c) mixing the mixture of step b) with the binder. In step S2, the nanofiber is any one of aramid nanofiber, carboxymethyl cellulose, cellulose nanofiber, microcrystalline cellulose, cellulose nanocrystal and cellulose nanonet, the inorganic nanofiller is any one of nano-silicon dioxide, graphene oxide, carbon nanotube, nano-clay, nano-aluminum oxide, nano-aluminum hydroxide, nano-zirconium oxide, nano-zinc borate, nano-titanium dioxide and nano-silicate, and the calcium ion regulator is any one of aqueous solutions of calcium fluoride, calcium chloride, calcium bromide, calcium nitrate and calcium acetate.

9. A thermal insulation-thermal conduction integrated phase change composite material, characterized in that, The composite material is obtained by the preparation method according to any one of claims 1-8.

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