Phase change energy storage material and preparation method thereof

Abstract

The invention belongs to the technical field of energy storage materials, and particularly relates to a phase change energy storage material and a preparation method thereof.The phase change energy storage material is prepared from 8-12 parts of phase change wax, 10-15 parts of ZnAl-LDH, 6-9 parts of SiC-CuS and 8 parts of polyethylene glycol dimethyl ether; according to the invention, the double-metal hydroxide and the phase-change wax are combined, interlayer water molecules and ionic bonds of the double-metal hydroxide can realize reversible phase change, the phase-change wax can be supported to reduce high-temperature flowing, the phase-change wax makes up for insufficient latent heat and improves energy storage capacity, and the combination of the double-metal hydroxide and the phase-change wax widens the phase-change temperature range and enhances cycle stability; in addition, Si-C loaded CuS nanosheets are introduced, energy can be transmitted under illumination or heat energy to assist storage, the smaller the size of the nanosheets is, the larger the specific surface area is, more active sites can be provided, the heat conduction efficiency is improved, complementation of all advantages of the material is achieved through a simple method, and good comprehensive performance is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage materials, and specifically refers to a phase change energy storage material and a preparation method thereof. Background Art

[0002] As a functional material, the phase change energy storage material can absorb or release a large amount of latent heat through a phase change process at a specific temperature, thereby realizing energy storage and regulation.

[0003] The phase change energy storage materials in the prior art are mainly divided into two categories: organic phase change materials and inorganic phase change materials; the organic phase change materials have the following deficiencies. Their thermal conductivity is usually low, resulting in slow heat transfer speed, which affects the rapid storage and release of energy; and in a high-temperature environment, the organic phase change materials are prone to flowing phenomenon; the phase change latent heat of the inorganic phase change materials is relatively not ideal. After multiple heating-cooling cycles, the structure of the inorganic materials is easily damaged, which in turn causes performance attenuation, seriously affecting their long-term use reliability and energy storage effect, and unable to ensure stable phase change energy storage function in a long period.

[0004] Based on the above, it is crucial to study a phase change energy storage material to make up for the problems of the prior art. Summary of the Invention

[0005] In order to overcome the defects existing in the prior art, the present invention combines double metal hydroxide with phase change wax. The double metal hydroxide not only has a reversible phase change process of desorption and adsorption of interlayer water molecules when the temperature changes, but also the breaking and synthesis of ionic bonds can achieve reversible phase change, and can also provide structural support for the phase change wax to reduce the high-temperature flowing problem. The phase change wax makes up for the insufficient phase change latent heat of the double metal hydroxide and improves the overall energy storage capacity. The combination of the two can flexibly broaden the phase change temperature range, and the double metal hydroxide can maintain the layered structure, stabilize the structure of the phase change wax, reduce its performance attenuation in multiple cycles, improve the cycle stability of the composite phase change energy storage material and extend its service life; in addition, to ensure the high efficiency and conversion efficiency of the material, Si-C supported CuS nanosheets are introduced. The nanosheets can transfer energy to the double metal hydroxide and the phase change wax under light or heat energy conditions to achieve energy storage, and the smaller their size, the larger the specific surface area, which can provide more active sites for Si-C support and improve the thermal conductivity of the overall material. The overall high-efficiency and stable phase change energy storage material can be obtained through a simple preparation method.

[0006] To achieve the above object, the technical solution adopted by the present invention is a phase change energy storage material, which is prepared from the following raw materials in parts by weight: 8-12 parts of phase change wax, 10-15 parts of ZnAl-LDH, 6-9 parts of SiC-CuS, and 8 parts of polyethylene glycol dimethyl ether.

[0007] Further, the preparation method of the SiC-CuS includes the following steps:

[0008] (a) Weigh 2 - 4 parts of copper nitrate trihydrate and add it to 30 parts of deionized water. Adjust the pH range to 7.5 - 8.5 with an alkali solution, where the concentration of the alkali solution is 0.5 mol / L, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain the pre-reaction solution;

[0009] (b) Weigh 4.5 - 9 parts of thiourea and add it to the pre-reaction solution obtained in step (a). Stir for 30 min under the condition of a rotation speed of 500 r / min, then place it in a hydrothermal autoclave and carry out a hydrothermal reaction at a temperature of 80 - 120 °C for 15 h to obtain a precipitate. Centrifuge and wash the precipitate with deionized water and absolute ethanol alternately for 3 times each, and dry it in a blast drying oven at 65 °C for 24 h to obtain CuS;

[0010] (c) Weigh 3 - 6 parts of SiC for drying treatment, add it to 10 parts of CuS obtained in step (b), and grind and mix them evenly to obtain the SiC-CuS precursor;

[0011] (d) Under the condition of an argon atmosphere with a flow rate of 300 mL / min, place the SiC-CuS precursor obtained in step (c) into a tube furnace with a temperature rising from room temperature to 350 - 450 °C, keep the temperature for calcination for 4 h, with a heating rate of 5 °C / min, and naturally cool to room temperature to obtain SiC-CuS.

[0012] Further, the preparation method of the ZnAl-LDH includes the following steps:

[0013] (i) Weigh 1 - 1.5 parts of zinc nitrate hexahydrate and add it to 20 parts of deionized water. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution A. Weigh 2.5 - 4 parts of aluminum nitrate nonahydrate and add it to 20 parts of deionized water. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution B;

[0014] (ii) Add solution A obtained in step (i) to solution B obtained in step (i), add an alkali solution to adjust the pH range to 8 - 10, where the concentration of the alkali solution is 1 mol / L, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain the mixed solution I;

[0015] (iii) Carry out a hydrothermal reaction on the mixed solution I obtained in step (ii) at a temperature of 120 - 150 °C for 24 h, and naturally cool to room temperature to obtain the ZnAl-LDH precursor;

[0016] (vi)The ZnAl-LDH precursor obtained in step (iii) was washed alternately with deionized water and absolute ethanol by centrifugation three times each, and dried in a forced-air drying oven at 65 °C for 24 h to obtain ZnAl-LDH.

[0017] The present invention also provides a method for preparing a straw aerogel composite thermal insulation board, comprising the following steps:

[0018] Step 1: Weigh 10-15 parts of ZnAl-LDH and add it to 25 parts of absolute ethanol, stir at a speed of 500 r / min for 30 min to obtain reaction solution A. Weigh 6-9 parts of SiC-CuS and add it to 25 parts of absolute ethanol, stir at a speed of 500 r / min for 30 min to obtain reaction solution B;

[0019] Step 2: Weigh 8-12 parts of phase change wax and 8 parts of polyethylene glycol dimethyl ether. Add the phase change wax to the polyethylene glycol dimethyl ether, heat at 70 °C for 40 min, and stir at a speed of 500 r / min to obtain mixture I;

[0020] Step 3: Add the reaction solution A obtained in Step 1 to the mixture I obtained in Step 2, ultrasonicate at a power of 0.5 KW for 20 min, heat at a temperature of 60 °C and stir at a speed of 500 r / min to obtain mixture II;

[0021] Step 4: Add the reaction solution B obtained in Step 1 to the mixture II obtained in Step 3, ultrasonicate at a power of 0.5 KW for 30 min, and stir at a speed of 500 r / min. Heat the temperature to 75 °C and maintain for 3 h, and cool naturally to room temperature to obtain a phase change energy storage material.

[0022] The beneficial effects achieved by the present invention are as follows:

[0023] The phase change energy storage material prepared by the present invention combines double metal hydroxide and phase change wax for the first time. On the one hand, the water molecules between the layers of the double metal hydroxide can undergo a reversible phase change process of desorption and adsorption when the temperature changes. On the other hand, as an ionic compound, the double metal hydroxide can also achieve a reversible phase change process through the breaking and synthesis of its ionic bonds. At the same time, the double metal hydroxide can provide a certain structural support for the phase change wax, reducing its high-temperature flow problem. At the same time, the phase change wax can make up for the possible lack of latent heat of phase change of the double metal hydroxide, improving the overall energy storage capacity. After the two are compounded, the phase change temperature range of the composite phase change material can be flexibly broadened. In addition, after the double metal hydroxide itself undergoes multiple heating-cooling cycles, its layered structure has a certain retention ability, and the reversible process of desorption and adsorption of water molecules between the layers can be well maintained, playing a certain role in stabilizing the structure of the phase change wax and reducing the performance attenuation of the phase change wax caused by changes in the molecular chain structure during multiple cycles, thereby improving the cycle stability of the entire composite phase change energy storage material and extending its service life.

[0024] In order to ensure the high efficiency and conversion efficiency of the phase change energy storage material, the phase change energy storage material prepared by the present invention can transfer energy to the double metal hydroxide and the phase change wax under the conditions of light or heat energy by introducing Si-C loaded CuS nanosheets, and realize energy storage through the phase change of the material; at the same time, the smaller the size of the synthesized CuS nanosheets, the larger its specific surface area and the higher the proportion of surface atoms, providing more active sites for the loading of Si-C and improving the thermal conductivity efficiency of the overall material.

[0025] The present invention obtains a highly efficient and stable phase change energy storage material through a simple preparation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a diagram of the preparation method of the phase change energy storage material proposed by the present invention;

[0027] Figure 2 It is the phase spectrum diagram of ZnAl-LDH in the phase change energy storage material prepared in Example 2 of the present invention;

[0028] Figure 3 It is the phase spectrum diagram of CuS in the phase change energy storage material prepared in Example 2 of the present invention;

[0029] Figure 4 It is the SEM diagram of CuS in the phase change energy storage material prepared in Example 2 of the present invention;

[0030] Figure 5 It is the TEM diagram of SiC-CuS in the phase change energy storage material prepared in Example 2 of the present invention;

[0031] Figure 6High-resolution test chart of SiC-CuS in the phase change energy storage material prepared in Example 2 of the present invention;

[0032] Figure 7 Absorbance performance test chart of SiC-CuS in the phase change energy storage material prepared in Example 2 of the present invention;

[0033] Figure 8 Unidirectional differential scanning calorimetry chart of the phase change energy storage material prepared in Example 2 of the present invention.

[0034] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are only for demonstration purposes and do not limit the content of this application.

[0037] The preparation methods and test charts in the following embodiments refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 , unless otherwise specified, are all conventional methods; the materials used in the following embodiments, unless otherwise specified, are in parts by mass, and the materials used are all newly purchased materials in the market, and paraffin is selected as the phase change wax.

[0038] Example 1: A phase change energy storage material is prepared from the following raw materials in parts by weight: 8 parts of paraffin, 10 parts of ZnAl-LDH, 6 parts of SiC-CuS, and 8 parts of polyethylene glycol dimethyl ether.

[0039] The preparation method of SiC-CuS includes the following steps:

[0040] (a)Weigh 2 portions of copper nitrate trihydrate, add them to 30 portions of deionized water, adjust the pH to 7.5 with 0.5 mol / L sodium hydroxide solution, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain the pre-reaction solution.

[0041] (b)Weigh 4.5 portions of thiourea, add it to the pre-reaction solution obtained in step (a), stir for 30 min under the condition of a rotation speed of 500 r / min, place it in a hydrothermal reactor, heat the temperature to 80 °C for hydrothermal reaction for 15 h to obtain a precipitate. Wash the precipitate alternately with deionized water and absolute ethanol by centrifugation 3 times each, and dry it in a blast drying oven at 65 °C for 24 h to obtain CuS.

[0042] (c)Weigh 3 portions of SiC, dry it in a blast drying oven at 65 °C for 12 h, add 10 portions of CuS obtained in step (b), and grind and mix them evenly to obtain the SiC-CuS precursor.

[0043] (d)Under the condition of an argon atmosphere with a flow rate of 300 mL / min, place the SiC-CuS precursor obtained in step (c) into a tubular furnace with a temperature rising from room temperature to 350 °C, keep the temperature for calcination for 4 h, with a heating rate of 5 °C / min, and naturally cool to room temperature to obtain SiC-CuS.

[0044] The preparation method of ZnAl-LDH includes the following steps:

[0045] (i)Weigh 1 portion of zinc nitrate hexahydrate, add it to 20 portions of deionized water, stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution A. Weigh 2.5 portions of aluminum nitrate nonahydrate, add it to 20 portions of deionized water, stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution B.

[0046] (ii)Add solution A obtained in step (i) to solution B obtained in step (i), adjust the pH to 8 with 1 mol / L sodium hydroxide solution, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain the mixed solution I.

[0047] (iii)Carry out hydrothermal reaction on the mixed solution I obtained in step (ii) at 120 °C for 24 h, and naturally cool to room temperature to obtain the ZnAl-LDH precursor.

[0048] (vi)Wash the ZnAl-LDH precursor obtained in step (iii) alternately with deionized water and absolute ethanol by centrifugation 3 times each, and dry it in a blast drying oven at 65 °C for 24 h to obtain ZnAl-LDH.

[0049] This example also provides a preparation method of a phase change energy storage material, including the following steps:

[0050] Step 1: Weigh 10 parts of ZnAl-LDH and add it to 25 parts of absolute ethanol. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain reaction solution A. Weigh 6 parts of SiC-CuS and add it to 25 parts of absolute ethanol. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain reaction solution B;

[0051] Step 2: Weigh 8 parts of paraffin wax and 8 parts of polyethylene glycol dimethyl ether. Add the paraffin wax to the polyethylene glycol dimethyl ether, heat at 70 °C for 40 min, and stir at a rotation speed of 500 r / min to obtain mixture I;

[0052] Step 3: Add the reaction solution A obtained in Step 1 to the mixture I obtained in Step 2, ultrasonicate for 20 min under the condition of a power of 0.5 KW, heat at a temperature of 60 °C and stir at a rotation speed of 500 r / min to obtain mixture II;

[0053] Step 4: Add the reaction solution B obtained in Step 1 to the mixture II obtained in Step 3, ultrasonicate for 30 min under the condition of a power of 0.5 KW, and stir at a rotation speed of 500 r / min. Heat the temperature to 75 °C and maintain for 3 h, and then cool naturally to room temperature to obtain the phase change energy storage material.

[0054] Example 2: A phase change energy storage material is prepared from the following raw materials in parts by weight: 10 parts of paraffin wax, 13 parts of ZnAl-LDH, 7.5 parts of SiC-CuS, and 8 parts of polyethylene glycol dimethyl ether.

[0055] The preparation method of SiC-CuS includes the following steps:

[0056] (a) Weigh 3 parts of copper nitrate trihydrate and add it to 30 parts of deionized water. Add 0.5 mol / L sodium hydroxide solution to adjust the pH to 8, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain the pre-reaction solution;

[0057] (b) Weigh 6.8 parts of thiourea and add it to the pre-reaction solution obtained in step (a). Stir for 30 min under the condition of a rotation speed of 500 r / min, put it into a hydrothermal reactor, heat the temperature to 100 °C, and carry out hydrothermal reaction for 15 h to obtain a precipitate. Centrifuge and wash the precipitate with deionized water and absolute ethanol alternately for 3 times each, and dry it in a blast drying oven at 65 °C for 24 h to obtain CuS;

[0058] (c) Weigh 4.5 parts of SiC and dry it in a blast drying oven at 65 °C for 12 h. Add it to 10 parts of CuS obtained in step (b) and grind and mix evenly to obtain the SiC-CuS precursor;

[0059] (d) The SiC-CuS precursor obtained in step (c) was placed in a tubular furnace with an argon atmosphere at a flow rate of 300 mL / min. The temperature of the furnace was raised from room temperature to 400 °C at a heating rate of 5 °C / min, and then calcined at this temperature for 4 h. After natural cooling to room temperature, SiC-CuS was obtained.

[0060] The preparation method of ZnAl-LDH includes the following steps:

[0061] (i) Weigh 1.3 parts of zinc nitrate hexahydrate and add it to 20 parts of deionized water. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution A. Weigh 3.3 parts of aluminum nitrate nonahydrate and add it to 20 parts of deionized water. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution B;

[0062] (ii) Add the solution A obtained in step (i) to the solution B obtained in step (i), add 1 mol / L sodium hydroxide solution to adjust the pH to 9, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain mixture I;

[0063] (iii) Carry out hydrothermal reaction on the mixture I obtained in step (ii) at 135 °C for 24 h, and then cool it to room temperature naturally to obtain the ZnAl-LDH precursor;

[0064] (vi) The ZnAl-LDH precursor obtained in step (iii) was centrifugally washed with deionized water and absolute ethanol alternately for 3 times each, and then dried in a blast drying oven at 65 °C for 24 h to obtain ZnAl-LDH.

[0065] This example also provides a preparation method of a phase change energy storage material, including the following steps:

[0066] Step 1: Weigh 13 parts of ZnAl-LDH and add it to 25 parts of absolute ethanol. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain reaction solution A. Weigh 7.5 parts of SiC-CuS and add it to 25 parts of absolute ethanol. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain reaction solution B;

[0067] Step 2: Weigh 10 parts of paraffin and 8 parts of polyethylene glycol dimethyl ether. Add the paraffin to the polyethylene glycol dimethyl ether, heat it at 70 °C for 40 min, and stir at a rotation speed of 500 r / min to obtain mixture I;

[0068] Step 3: Add the reaction solution A obtained in step 1 to the mixture I obtained in step 2, ultrasonicate for 20 min under the condition of a power of 0.5 KW, heat at 60 °C and stir at a rotation speed of 500 r / min to obtain mixture II;

[0069] Step 4: Add the reaction solution B obtained in Step 1 into the mixed solution II obtained in Step 3, ultrasonicate for 30 min under the condition of a power of 0.5 KW, stir at a rotation speed of 500 r / min, heat the temperature to 75 °C and maintain for 3 h, and cool naturally to room temperature to obtain the phase change energy storage material.

[0070] Example 3: A phase change energy storage material is prepared from the following raw materials in parts by weight: 12 parts of paraffin, 15 parts of ZnAl-LDH, 9 parts of SiC-CuS, and 8 parts of polyethylene glycol dimethyl ether.

[0071] The preparation method of SiC-CuS includes the following steps:

[0072] (a) Weigh 4 parts of copper nitrate trihydrate and add it to 30 parts of deionized water. Add 0.5 mol / L sodium hydroxide solution to adjust the pH to 8.5, and stir for 30 min under the condition of a rotation speed of 500 r / min to obtain the pre-reaction solution;

[0073] (b) Weigh 9 parts of thiourea and add it to the pre-reaction solution obtained in step (a). Stir for 30 min under the condition of a rotation speed of 500 r / min, put it into a hydrothermal autoclave, heat the temperature to 120 °C for hydrothermal reaction for 15 h to obtain a precipitate. Wash the precipitate with deionized water and absolute ethanol alternately by centrifugation 3 times each, and dry it in a blast drying oven at 65 °C for 24 h to obtain CuS;

[0074] (c) Weigh 6 parts of SiC and dry it in a blast drying oven at 65 °C for 12 h. Add 10 parts of CuS obtained in step (b) and grind and mix evenly to obtain the SiC-CuS precursor;

[0075] (d) Under the condition of an argon atmosphere with a flow rate of 300 mL / min, put the SiC-CuS precursor obtained in step (c) into a tube furnace with a temperature rising from room temperature to 450 °C, maintain the temperature for calcination for 4 h, and the heating rate is 5 °C / min. Cool naturally to room temperature to obtain SiC-CuS.

[0076] The preparation method of ZnAl-LDH includes the following steps:

[0077] (i) Weigh 1.5 parts of zinc nitrate hexahydrate and add it to 20 parts of deionized water. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution A. Weigh 4 parts of aluminum nitrate nonahydrate and add it to 20 parts of deionized water. Stir for 30 min under the condition of a rotation speed of 500 r / min to obtain solution B;

[0078] (ii) Add the solution A obtained in step (i) to the solution B obtained in step (i), adjust the pH to 10 with 1 mol / L sodium hydroxide solution, and stir for 30 min at a rotation speed of 500 r / min to obtain a mixed solution I;

[0079] (iii) Carry out a hydrothermal reaction on the mixed solution I obtained in step (ii) at a temperature of 150 °C for 24 h, and naturally cool it to room temperature to obtain a ZnAl-LDH precursor;

[0080] (vi) Wash the ZnAl-LDH precursor obtained in step (iii) 3 times each by alternate centrifugation with deionized water and absolute ethanol, and dry it in a blast drying oven at 65 °C for 24 h to obtain ZnAl-LDH.

[0081] This example also provides a preparation method of a phase change energy storage material, including the following steps:

[0082] Step 1: Weigh 15 parts of ZnAl-LDH and add it to 25 parts of absolute ethanol, stir for 30 min at a rotation speed of 500 r / min to obtain a reaction solution A. Weigh 9 parts of SiC-CuS and add it to 25 parts of absolute ethanol, stir for 30 min at a rotation speed of 500 r / min to obtain a reaction solution B;

[0083] Step 2: Weigh 12 parts of paraffin wax and 8 parts of polyethylene glycol dimethyl ether. Add the paraffin wax to the polyethylene glycol dimethyl ether, heat at 70 °C for 40 min, and stir at a rotation speed of 500 r / min to obtain a mixed solution I;

[0084] Step 3: Add the reaction solution A obtained in step 1 to the mixed solution I obtained in step 2, carry out ultrasonic treatment for 20 min under the condition of a power of 0.5 KW, heat the temperature to 60 °C and stir at a rotation speed of 500 r / min to obtain a mixed solution II;

[0085] Step 4: Add the reaction solution B obtained in step 1 to the mixed solution II obtained in step 3, carry out ultrasonic treatment for 30 min under the condition of a power of 0.5 KW, and stir at a rotation speed of 500 r / min. Heat the temperature to 75 °C and keep it for 3 h, and naturally cool it to room temperature to obtain the phase change energy storage material.

[0086] The difference between Example 4 and Example 2 is that the sodium hydroxide solution is replaced with a potassium hydroxide solution, and the rest is the same as in Example 2.

[0087] Comparative example:

[0088] The difference between Comparative Example 1 and Example 2 is that ZnAl-LDH is not added, and the rest is the same as in Example 2;

[0089] The difference between Comparative Example 2 and Example 2 lies in that SiC-CuS was not added, and the rest was the same as in Example 2;

[0090] The difference between Comparative Example 3 and Example 2 lies in that ZnAl-LDH and SiC-CuS were not added, and the rest was the same as in Example 2;

[0091] The performance of the prepared phase change energy storage materials was tested and analyzed as follows:

[0092] Among them Figure 2 is the XRD pattern of ZnAl-LDH. It can be seen that the diffraction peaks of ZnAl-LDH at 2θ of 11.64°, 23.39°, 34.56°, 39.15° and 46.64° correspond to the 003, 006, 012, 015 and 018 crystal planes of ZnAl-LDH-JCPDS Figure 2 38-0486 respectively, indicating that ZnAl-LDH was successfully prepared; # 38-0486, indicating that ZnAl-LDH was successfully prepared; Figure 3 is the XRD pattern of CuS. It can be seen that the diffraction peaks of CuS at 2θ of 29.27°, 31.78°, 32.85° and 47.94° correspond to the 102, 103, 006 and 110 crystal planes of CuS-JCPDS Figure 3 06-0464 respectively, indicating that CuS was successfully prepared; There are no other miscellaneous peaks in the XRD patterns of the above materials, indicating that the prepared materials have high purity. # 06-0464 respectively, indicating that CuS was successfully prepared; There are no other miscellaneous peaks in the XRD patterns of the above materials, indicating that the prepared materials have high purity. Figure 4 is the SEM image of CuS. It can be seen that it has a uniform nanosheet structure, providing more active sites for the loading of SiC, Figure 5 is the TEM image of SiC-CuS. It can be seen that the two are closely adhered, indicating that SiC was successfully loaded on the surface of CuS, Figure 6 is the high-resolution test image of SiC-CuS. Among them, D = 0.282 nm corresponds to the 103 crystal plane of CuS, further indicating that SiC-CuS was successfully prepared; Figure 7 is the light absorption performance test image of SiC-CuS. It can be seen that the loading of SiC causes a blue shift in the light absorption performance of CuS, improving the light absorption of CuS in the visible light range; Figure 8 is the one-way differential scanning calorimetry chart of the prepared phase change energy storage material. It can be seen that the phase change temperature of the phase change energy storage material prepared in Example 2 is 84.23 °C, the phase change enthalpy value of the phase change energy storage material is 261 J / g, and the thermal conductivity is 7.81 W / (m·K).

[0093] Table 1 shows the performance data of the phase change energy storage materials prepared in the examples and comparative examples:

[0094]

[0095] From the data comparison in Table 1 above, it can be obtained that the phase change temperature of the phase change energy storage material prepared in the example is higher than that of the comparative example, and at the same time, it has a higher phase change enthalpy value and thermal conductivity, indicating that the prepared phase change energy storage material has a better energy storage effect.

[0096] Obviously, the above comparative examples and examples are only a part of the comparative examples and examples of the present invention, and the scope of protection of the present invention includes all comparative examples and examples based on such references.

[0097] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0098] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual application is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar methods and embodiments without creative efforts without departing from the purpose of the present invention, they shall fall within the scope of protection of the present invention.

Claims

1. A phase change energy storage material, characterized in that: The invention is prepared from the following raw materials in parts by weight: 8-12 parts of phase change wax, 10-15 parts of ZnAl-LDH, 6-9 parts of SiC-CuS and 8 parts of polyethylene glycol dimethyl ether; The raw materials for preparing the ZnAl-LDH include zinc nitrate hexahydrate and aluminum nitrate nonahydrate, and the mass ratio of the zinc nitrate hexahydrate to the aluminum nitrate nonahydrate is 1-1.5:2.5-4; The raw materials for preparing the SiC-CuS include copper nitrate trihydrate, thiourea and SiC, and the mass ratio of the copper nitrate trihydrate to thiourea is 2-4:4.5-9.

2. A phase change energy storage material according to claim 1, characterized in that: The preparation method of SiC-CuS comprises the following steps: (a) copper nitrate trihydrate is weighed and added to deionized water, and an alkali solution is added to adjust the pH and stirred to obtain a pre-reaction solution; (b) weighing thiourea, adding it to the pre-reaction solution obtained in step (a), stirring, and hydrothermally reacting to obtain a precipitate, washing and drying the precipitate to obtain CuS; (c) weighing SiC, drying it, adding the CuS obtained in step (b), grinding and mixing, and obtaining a SiC-CuS precursor; (d) calcining the SiC-CuS precursor obtained in step (c), and cooling to obtain SiC-CuS.

3. A phase change energy storage material according to claim 2, characterized in that: The alkali solution in step (a) is a sodium hydroxide solution or a potassium hydroxide solution, the concentration of the alkali solution is 0.5 mol / L, the pH range is 7.5-8.5, and the mass ratio of SiC to CuS in step (c) is 3-6:

10.

4. A phase change energy storage material according to claim 1, characterized in that: The preparation method of the ZnAl-LDH comprises the following steps: (i) Weigh zinc nitrate hexahydrate, add it to deionized water and stir it to obtain solution A, and weigh aluminum nitrate nonahydrate, add it to deionized water and stir it to obtain solution B; (ii) adding the solution A obtained in step (i) to the solution B obtained in step (i), adding an alkali solution to adjust the pH and stirring to obtain a mixed solution I; (iii) subjecting the mixed solution I obtained in step (ii) to a hydrothermal reaction, and cooling the mixture to obtain a ZnAl-LDH precursor; (vi) washing and drying the ZnAl-LDH precursor obtained in step (iii) to obtain ZnAl-LDH.

5. A phase change energy storage material according to claim 4, characterized in that: The alkali solution in step (ii) is a sodium hydroxide solution or a potassium hydroxide solution, the concentration of the alkali solution is 1 mol / L, and the pH range is 8-10.

6. A method for preparing a phase change energy storage material according to any one of claims 1 to 5, characterized in that: The steps include: Step 1, weighing ZnAl-LDH, adding it to anhydrous ethanol, stirring, and obtaining a reaction solution A, weighing SiC-CuS, adding it to anhydrous ethanol, stirring, and obtaining a reaction solution B; Step 2, weighing phase change wax and polyethylene glycol dimethyl ether, adding the phase change wax to the polyethylene glycol dimethyl ether, heating and stirring to obtain a mixed solution I; Step 3, adding the reaction solution A obtained in step 1 to the mixed solution I obtained in step 2, ultrasonicating, heating and stirring to obtain a mixed solution II; Step 4: Add the reaction solution B obtained in step 1 to the mixed solution II obtained in step 3, ultrasonicate and stir, heat, and cool to obtain a phase change energy storage material.

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