A silkworm cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material and its preparation method

Abstract

This invention provides a cocoon-shaped aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material and its preparation method. The cocoon-shaped aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material prepared by this invention can produce stable, micron-sized cocoon-shaped granular phase change composite materials with a larger specific surface area. The obtained phase change composite material has improved thermal conductivity, increased heat transfer area, better cycle performance, higher thermal conductivity, and better thermal stability. Moreover, the granular phase change composite material is more convenient to use, the preparation process is simple, and it is easy to promote and apply.

Description

Technical Field

[0001] This invention belongs to the field of phase change material thermal storage technology, specifically relating to a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material and its preparation method. Background Technology

[0002] With the proposal of the "zero carbon" goal, sustainable development has gradually become a global consensus, and renewable energy is gradually replacing most fossil fuels. New renewable energy sources, represented by solar energy, are widely considered the most important renewable energy source due to their significant advantages of being inexhaustible. However, the spatiotemporal mismatch problem of solar energy limits its development. Phase change materials, which can store and release large amounts of heat energy during phase change, are considered ideal materials for solar thermal conversion and heat storage.

[0003] Phase change materials (PCMs), as energy storage media, can store or release large amounts of energy at near-constant temperatures during melting or solidification, achieving efficient energy utilization and thus reducing CO2 emissions. Common organic PCMs, such as paraffin wax (PW), polyethylene glycol (PEG), and fatty acids, are white substances. When sunlight shines on PCMs, light waves are reflected, resulting in poor sunlight capture capabilities. Therefore, photothermal conversion materials can be introduced into the field of phase change energy storage. Photothermal conversion materials are materials that can convert light energy into heat energy through their own photothermal conversion mechanism under illumination. The photon capture capability and the design and thermophysical properties of the heat storage material affect the photothermal conversion performance. Combining photothermal conversion materials with phase change materials allows the solar heat absorbed by the photothermal conversion materials to be stored in the phase change materials, achieving comprehensive performance such as high heat storage capacity, excellent photothermal conversion performance, and good thermal conductivity.

[0004] However, the flammability, volume expansion, leakage, compatibility, poor thermal conductivity, and poor photothermal conversion performance of phase change materials (PCMs) during the phase change process are the main problems hindering their development. Extensive research has focused primarily on novel shape-stable PCM (SS-PCM) composite PCMs. There are many composite methods for PCM thermal storage materials, commonly including blending, impregnation, micro / nanocapsule methods, sol-gel methods, porous adsorption methods, and intercalation methods.

[0005] Carbon nanotubes (CNTs) are widely used in photothermal conversion due to their excellent photothermal conversion performance and high thermal conductivity. Multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) have thermal conductivity of approximately 3000 W / (m·K) and 2000 W / (m·K), respectively. Adding carbon nanotubes to paraffin wax can form nano-reinforced heat transfer phase change materials with excellent heat transfer performance and good stability. However, contact thermal resistance exists between carbon nanotubes and between carbon nanotubes and paraffin wax, often leading to problems such as poor dispersibility and low stability during application, which limits their practical application in phase change energy storage.

[0006] Chen et al. (Electro-and photodriven phase change composites based on wax-infiltrated carbon nanotube sponges, ACS NANO, 2012, 6, 12, 10884-10892) disclosed an electrothermal and photothermal phase change composite material based on paraffin impregnation in porous, formable sponge-like carbon nanotubes. The material was prepared through the following steps: first, carbon nanotubes were deposited as sponges using chemical vapor deposition. These sponges were collected after forming on the inner wall of a reactor and then cut into rectangular blocks. Paraffin was dissolved in dichloromethane to obtain a solution with a concentration of 0.03 g / mL. The paraffin solution was then dropped onto the rectangular carbon nanotube sponges, where it was quickly absorbed. The solution was then placed in a low-pressure environment to evaporate the solvent, forming a dense, solid PW-CNTs phase change composite material with significant volume shrinkage. Although the above preparation methods can produce shape-stable phase change composite materials, the cost of obtaining sponge-like carbon nanotubes is high, the preparation process is difficult to control, and the formation of bulk PW-CNTs phase change composite materials is not conducive to application. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material with good thermal conductivity and thermal stability, and its preparation method.

[0008] To achieve the above objectives, the solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material, which is a cocoon-type phase change composite material with disordered entangled aminated multi-walled carbon nanotubes as the coating wire and a phase change material as the filling core material; the particle size of the cocoon-type phase change composite material is 1-50 μm; in the cocoon-type phase change composite material, the mass ratio of aminated multi-walled carbon nanotubes to phase change material is 1:(2-6).

[0010] Preferably, the particle size of the cocoon-type phase change composite material is 1-25 μm; in the cocoon-type phase change composite material, the mass ratio of aminated multi-walled carbon nanotubes to phase change material is 1:(3-5).

[0011] Preferably, the thermal conductivity of the cocoon-type phase change composite material is 0.3-0.5 W / (m·K), and the phase change enthalpy is between 11.3-193.0 J / g.

[0012] Preferably, the phase change material is selected from one or more of monohydric alcohol phase change materials, straight-chain alkane phase change materials, and fatty acid phase change materials. The monohydric alcohol phase change material is selected from one or more of dodecanol, tridecanol, tetradecanol, pentadecylol, and hexadecylol. The straight-chain alkane phase change material is selected from one or more of paraffin wax, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane. The fatty acid phase change material is selected from one or more of palmitic acid, stearic acid, lauric acid, myristic acid, and palmitic acid. Preferably, the phase change material is paraffin wax.

[0013] Secondly, the present invention also provides a method for preparing the cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material as described above, comprising the following steps:

[0014] Step (1): Aminated multi-walled carbon nanotubes are dissolved in deionized water and ultrasonically dispersed to obtain an aqueous solution of aminated multi-walled carbon nanotubes.

[0015] Step (2) involves melting the phase change material into a liquid at a melting temperature;

[0016] Step (3): At the same temperature, the molten phase change material is added to the aqueous solution of aminated multi-walled carbon nanotubes and stirred at high speed.

[0017] Step (4): After the reaction is complete, the mixture is filtered, washed, and dried to obtain a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material.

[0018] Preferably, in step (1), the aminated multi-walled carbon nanotubes have a diameter of 10-50 nm and a length of 10-20 μm; the aminated multi-walled carbon nanotubes are modified by aminated carboxylated multi-walled carbon nanotubes with diamines, wherein the diamines are selected from any one of ethylenediamine, hexamethylenediamine and decanediamine.

[0019] Preferably, in step (1), the mass ratio of the aminated multi-walled carbon nanotubes to the deionized water is 1:(100-200), and the mixture is ultrasonically dispersed for 1-2 hours.

[0020] Preferably, in step (2), the phase change material is selected from one or more of monohydric alcohol phase change materials, straight-chain alkane phase change materials, and fatty acid phase change materials. The monohydric alcohol phase change material is selected from one or more of dodecanol, tridecanol, tetradecanol, pentadecylol, and hexadecylol. The straight-chain alkane phase change material is selected from one or more of paraffin wax, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane. The fatty acid phase change material is selected from one or more of palmitic acid, stearic acid, lauric acid, myristic acid, and palmitic acid. Preferably, it is paraffin wax with a melting temperature of 60-80°C.

[0021] Preferably, in step (3), the temperature during mixing is 70-100℃, the volume ratio of the molten phase change material to the aqueous solution of aminated multi-walled carbon nanotubes is 1:(20-60), the stirring speed of the high-speed stirring is 14000-18000rpm, and the stirring time is 5-10min.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The cocoon-shaped aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material prepared by this invention can produce cocoon-shaped granular phase change composite materials with stable shapes and micron-sized particles. It has a larger specific surface area, and the obtained phase change composite material has improved thermal conductivity, increased heat transfer area, better cycle performance, higher thermal conductivity, and better thermal stability. Moreover, the granular phase change composite material is more convenient to use, the preparation process is simple, and it is easy to promote and apply. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the preparation process of the silkworm cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material involved in this invention.

[0025] Figure 2The figures show DSC data for phase change composite materials prepared with different mass ratios of paraffin and aminated multi-walled carbon nanotubes in the embodiments of this invention. The instrument used was a Mettler-Toledo DSC3 differential scanning calorimeter (heating and cooling range 5-80℃, heating and cooling rate 5℃ / min, N2 flow rate 50mL / min).

[0026] Figure 3 The thermal conductivity test data for phase change composite materials prepared with different volume ratios of molten paraffin to carbon nanotube aqueous solution in the embodiments of this invention are shown. The instrument used was a TCM (C-Therm Thermal Conductivity Meter) manufactured by C-Therm Technologies, Inc., Canada. The thermal conductivity of the phase change composite material samples was tested at 25 ± 0.5 °C (solid).

[0027] Figure 4 The images show schematic diagrams (a) and SEM images (b) of the particle structures of phase change composite materials prepared under different case conditions in the embodiments of the present invention.

[0028] Figure 5 The image shows the 50-cycle DSC thermal cycling diagram of the phase change composite material prepared in Example 2 of this invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] This invention provides a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material, the specific process of which is as follows: Figure 1 As shown, it includes the following steps:

[0031] Step 1: Dissolve aminated multi-walled carbon nanotubes in deionized water and disperse by ultrasonication to obtain an aqueous solution of aminated multi-walled carbon nanotubes.

[0032] In this step, the aminated multi-walled carbon nanotubes used in this invention are modified by amylating carboxylated multi-walled carbon nanotubes with diamines, including but not limited to ethylenediamine, hexamethylenediamine, and decanediamine.

[0033] Taking the amination modification of carboxylated multi-walled carbon nanotubes with ethylenediamine as an example, the amination multi-walled carbon nanotubes used in this invention can be prepared by the following steps: carboxylated multi-walled carbon nanotubes (MWCNTs-COOH), condensing agent DCC, and ethylenediamine (EDA) are ultrasonically mixed for 30 min, and then heated in an oil bath at 120°C for 24 h; after the reaction is completed, excess amine, DCC, and byproducts of the DCC reaction are ultrasonically washed away with anhydrous ethanol, filtered with a PTFE filter membrane, and the filtered carbon nanotubes are vacuum dried at 60°C for 24 h to obtain amination carbon nanotubes.

[0034] The chemical reaction formula between MWCNTs-COOH and EDA is:

[0035] MWCNTs-COOH+NH2-CH2-CH2-NH2→MWCNT-CO-NH-CH2-CH2-NH2

[0036] The prepared aminated carbon nanotubes have amino groups in their molecular formula that can covalently bond with many chemical substances through amination reactions, while the unique structure of the carbon nanotubes remains intact, preserving their excellent properties. The amino groups also improve the hydrophilicity and polarity of the carbon nanotube surface, thereby enhancing their dispersibility and solubility, and giving them high reactivity, allowing them to bond with various metal ions and polymers via amide bonds. In this invention, aminated multi-walled carbon nanotubes are directly mixed with molten phase change material. The amino groups on the aminated multi-walled carbon nanotubes can firmly bond with the phase change material. Ultrasonic dispersion and high-speed stirring further help the aminated multi-walled carbon nanotubes to be more completely and stably encapsulated on the surface of the phase change monomer, forming a shape-stable cocoon-shaped phase change composite material.

[0037] In this step, the mass ratio of aminated multi-walled carbon nanotubes to deionized water is 1:(100-200), and the mixture is ultrasonically dispersed for 1-2 hours to obtain an aqueous solution of aminated multi-walled carbon nanotubes.

[0038] Step 2: Melt the phase change material into a liquid at the melting temperature.

[0039] In this step, the phase change materials used in this invention include, but are not limited to, monohydric alcohol phase change materials, straight-chain alkane phase change materials, and fatty acid phase change materials. The monohydric alcohol phase change materials include, but are not limited to, dodecanol, tridecanol, tetradecanol, pentadecyl alcohol, and hexadecyl alcohol. The straight-chain alkane phase change materials include, but are not limited to, paraffin wax, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane. The fatty acid phase change materials include, but are not limited to, palmitic acid, stearic acid, lauric acid, myristic acid, and palmitic acid. In this embodiment of the invention, paraffin wax is used as an example, with a melting temperature of 60-80°C.

[0040] In some embodiments of the present invention, two or more phase change materials may be used as the core material of the microcapsule phase change material, such as a mixture of n-octadecane and n-tetracosane, all of which are within the protection scope of the present invention.

[0041] Step 3: At the same temperature, add the molten phase change material to the aqueous solution of aminated multi-walled carbon nanotubes and stir at high speed.

[0042] In this step, the mixing temperature should not be lower than the melting temperature of the phase change material, for example, it can be 70-100℃. The volume ratio of the molten phase change material to the aqueous solution of aminated multi-walled carbon nanotubes can be 1:(20-60). The stirring speed of the high-speed stirring can be 14000-18000 rpm and the stirring time can be 5-10 min.

[0043] Step 4: After the reaction is complete, the mixture is filtered, washed, and dried to obtain a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material.

[0044] Specifically, in this step: after the reaction is completed, the obtained sample is filtered, washed with deionized water at 70°C and hot ethanol at 70°C respectively, and the obtained product is placed in an oven at 60-80°C and dried to constant weight.

[0045] The cocoon-shaped aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material prepared by the method of this invention can simultaneously exhibit the phase change properties of the phase change monomer and the excellent photothermal conversion properties and high thermal conductivity of the aminated carbon nanotube. Furthermore, it can produce stable-shaped cocoon-shaped granular phase change composite materials (such as...) with randomly wound aminated multi-walled carbon nanotubes as the coating wire and a phase change material as the core filler. Figure 4 As shown in a), the particle size is in the micrometer range of 1-50 μm, and further, the particle size can be reduced to 1-25 μm. The preparation process of the present invention realizes a phase change composite material with a smaller particle size and a larger specific surface area. In the cocoon-shaped phase change composite material, the mass ratio of aminated multi-walled carbon nanotubes to phase change material is 1:(2-6), more preferably 1:(3-5). The obtained phase change composite material improves thermal conductivity, increases heat transfer area, has better cycle performance, higher thermal conductivity, and better thermal stability. Moreover, the particulate phase change composite material is more convenient to use, the preparation process is simple, and it is easy to promote and apply.

[0046] The cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material provided by this invention has important application prospects in many fields such as solar energy utilization, intelligent temperature control, heat dissipation of electronic devices and energy storage.

[0047] The present invention will be further illustrated below with reference to specific embodiments. The purpose of these embodiments is to provide a better understanding of the invention and to demonstrate its essential characteristics. Therefore, the examples given should not be considered as limitations on the scope of protection of the present invention. It is also specifically noted that, unless otherwise specified, the specific experimental methods and equipment involved in the embodiments are conventional methods or implemented according to the conditions recommended in the manufacturer's instructions, and the reagents involved are all commercially available unless otherwise specified.

[0048] Example 1:

[0049] In this embodiment, the mass of the aminated multi-walled carbon nanotubes is 1g, and the mass of the paraffin is 6g.

[0050] 1g of aminated multi-walled carbon nanotubes were placed in 100-200ml of deionized water and ultrasonically dispersed for 1-2 hours to prepare an aqueous solution. 6g of paraffin was added to a beaker and melted at 60-80℃. When both temperatures were equal, the molten paraffin was added to the aqueous solution, and the mixture was stirred at 14000-18000rpm for 5-10 minutes. The resulting sample was filtered and washed with 70℃ deionized water and 70℃ hot ethanol, respectively. After filtration, the product was dried in an oven at 60-80℃ until constant weight. Figure 2 The phase transition enthalpy is 193.0 ± 2.0 J / g.

[0051] Example 2:

[0052] In this embodiment, the mass of aminated multi-walled carbon nanotubes is 1g, and the mass of paraffin is 4g.

[0053] 1g of aminated multi-walled carbon nanotubes were placed in 100-200ml of deionized water and ultrasonically dispersed for 1-2 hours to prepare an aqueous solution. 4g of paraffin wax was added to a beaker and melted at 60-80℃. When both temperatures were equal, the molten paraffin wax was added to the aqueous solution, and the mixture was stirred at 14000-18000rpm for 5-10 minutes. The resulting sample was filtered and washed with 70℃ deionized water and 70℃ hot ethanol, respectively. After filtration, the product was dried in an oven at 60-80℃ until constant weight. Figure 2 The phase transition enthalpy is 75.6 ± 2.0 J / g.

[0054] Figure 5 This is a DSC thermal cycle diagram of the phase change composite material prepared in Example 2 of the present invention after 50 cycles. From... Figure 5 It can be seen that the phase change composite material prepared by the present invention still has excellent phase change performance after multiple cycles, indicating that the phase change composite material prepared by the present invention has good thermal stability and service life.

[0055] Example 3:

[0056] In this embodiment, the mass of the aminated multi-walled carbon nanotubes is 1g, and the mass of the paraffin is 2g.

[0057] 1g of aminated multi-walled carbon nanotubes were placed in 100-200ml of deionized water and ultrasonically dispersed for 1-2 hours to prepare an aqueous solution. 2g of paraffin was added to a beaker and melted at 60-80℃. When both temperatures were equal, the molten paraffin was added to the aqueous solution, and the mixture was stirred at 14000-18000rpm for 5-10 minutes. The resulting sample was filtered and washed with 70℃ deionized water and 70℃ hot ethanol, respectively. After filtration, the product was dried in an oven at 60-80℃ until constant weight. Figure 2 The phase transition enthalpy is 11.3 ± 2.0 J / g.

[0058] Example 4:

[0059] In this embodiment, the volume of molten paraffin is 5 ml, and the volume of the aqueous solution of aminated carbon nanotubes is 100 ml.

[0060] 1g of aminated multi-walled carbon nanotubes were placed in 100ml of deionized water and ultrasonically dispersed for 1-2 hours to prepare an aqueous solution. 4.5g of paraffin wax was added to a beaker and melted at 60-80℃. When both temperatures were equal, the molten paraffin wax was added to the aqueous solution, and the mixture was stirred at 14000-18000 rpm for 5-10 minutes. The resulting sample was filtered and washed with 70℃ deionized water and 70℃ hot ethanol, respectively. After filtration, the product was dried in an oven at 60-80℃ until constant weight. Figure 3 The thermal conductivity of the composite material was calculated to be 0.30 ± 0.01 W / (m·K).

[0061] Example 5:

[0062] In this embodiment, the volume of molten paraffin is 3 ml, and the volume of the aqueous solution of aminated carbon nanotubes is 180 ml.

[0063] 1g of aminated multi-walled carbon nanotubes were placed in 180ml of deionized water and ultrasonically dispersed for 1-2 hours to prepare an aqueous solution. 2.7g of paraffin was added to a beaker and melted at 60-80℃. When both temperatures were equal, the molten paraffin was added to the aqueous solution, and the mixture was stirred at 14000-18000rpm for 5-10 minutes. The resulting sample was filtered and washed with 70℃ deionized water and 70℃ hot ethanol, respectively. After filtration, the product was dried in an oven at 60-80℃ until constant weight. Figure 3 The thermal conductivity of the composite material was calculated to be 0.50 ± 0.01 W / (m·K).

[0064] Figure 4 b is a SEM image of the aminated multi-walled carbon nanotubes prepared in this embodiment. It can be seen that the prepared aminated multi-walled carbon nanotubes completely encapsulate and wrap around the paraffin, promoting heat transfer.

[0065] Compared with Example 4, its thermal conductivity increased by 67%, indicating that the heat transfer performance of the aminated multi-walled carbon nanotubes prepared in Example 5 was significantly improved.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cocoon type amino-functionalized multi-walled carbon nanotube-paraffin light-to-heat conversion phase change composite material, characterized in that, The present invention is a cocoon-type phase change composite material with disordered entangled aminated multi-walled carbon nanotubes as the coating wire and phase change material as the filling core material; the particle size of the cocoon-type phase change composite material is 1-50 μm; in the cocoon-type phase change composite material, the mass ratio of aminated multi-walled carbon nanotubes to phase change material is 1:(2-6). The aminated multi-walled carbon nanotubes have a diameter of 10-50 nm and a length of 10-20 μm. The aminated multi-walled carbon nanotubes are obtained by aminated modification of carboxylated multi-walled carbon nanotubes with diamines, wherein the diamine is selected from any one of ethylenediamine, hexamethylenediamine, and decanediamine.

2. The cocoon type amino-functionalized multi-walled carbon nanotube-paraffin light-to-heat conversion phase change composite material according to claim 1, characterized in that, The particle size of the cocoon-type phase change composite material is 1-25 μm; in the cocoon-type phase change composite material, the mass ratio of aminated multi-walled carbon nanotubes to phase change material is 1:(3-5).

3. The cocoon type amino-functionalized multi-walled carbon nanotube-paraffin light-to-heat conversion phase change composite material according to claim 1, characterized in that, The thermal conductivity of the cocoon-type phase change composite material is 0.3-0.5 W / (m·K), and the phase change enthalpy is between 11.3-193.0 J / g.

4. The cocoon type amino-functionalized multi-walled carbon nanotube-paraffin light-to-heat conversion phase change composite material according to claim 1, characterized in that, The phase change material is selected from one or more of monohydric alcohol phase change materials, straight-chain alkane phase change materials, and fatty acid phase change materials. The monohydric alcohol phase change material is selected from one or more of dodecanol, tridecanol, tetradecanol, pentadecylol, and hexadecylol. The straight-chain alkane phase change material is selected from one or more of paraffin wax, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane. The fatty acid phase change material is selected from one or more of palmitic acid, stearic acid, lauric acid, myristic acid, and palmitic acid.

5. A method for preparing a cocoon-shaped amino-functionalized multi-walled carbon nanotube-paraffin light-to-heat conversion phase change composite material according to any one of claims 1 to 4, characterized in that, Includes the following steps: Step (1): Aminated multi-walled carbon nanotubes are dissolved in deionized water and ultrasonically dispersed to obtain an aqueous solution of aminated multi-walled carbon nanotubes. Step (2) involves melting the phase change material into a liquid at a melting temperature; Step (3): At the same temperature, the molten phase change material is added to the aqueous solution of aminated multi-walled carbon nanotubes and stirred at high speed. Step (4): After the reaction is complete, the mixture is filtered, washed, and dried to obtain a cocoon-type aminated multi-walled carbon nanotube-paraffin photothermal conversion phase change composite material.

6. The production method according to claim 5, wherein In step (1), the mass ratio of the aminated multi-walled carbon nanotubes to the deionized water is 1:(100-200), and the mixture is ultrasonically dispersed for 1-2 hours.

7. The preparation method according to claim 5, characterized in that, In step (2), the phase change material is selected from one or more of monohydric alcohol phase change materials, straight-chain alkane phase change materials, and fatty acid phase change materials. The monohydric alcohol phase change material is selected from one or more of dodecanol, tridecanol, tetradecanol, pentadecylol, and hexadecylol. The straight-chain alkane phase change material is selected from one or more of paraffin wax, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane. The fatty acid phase change material is selected from one or more of palmitic acid, stearic acid, lauric acid, myristic acid, and palmitic acid.

8. The preparation method according to claim 5, characterized in that, In step (3), the temperature during mixing is 70-100℃, the volume ratio of the molten phase change material to the aqueous solution of aminated multi-walled carbon nanotubes is 1:(20-60), the stirring speed of the high-speed stirring is 14000-18000rpm, and the stirring time is 5-10min.

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