Triple network packaged inorganic hydrated salt phase change gel material and preparation method thereof

Abstract

The invention relates to the technical field of phase change materials, and discloses a triple network packaged inorganic hydrated salt phase change gel material and a preparation method thereof. The preparation method comprises the following steps: heating and stirring inorganic hydrated salt and urea to obtain dispersion liquid A; adding a nucleating agent into the dispersion liquid A, heating and stirring to obtain dispersion liquid B; adding a boron nitride material into the dispersion liquid B, heating and stirring to obtain dispersion liquid C; adding acrylamide, sodium acrylate and a polyvinyl alcohol aqueous solution into the dispersion liquid C, heating and stirring to obtain dispersion liquid D; adding N, N-methylene bisacrylamide into the dispersion liquid D, heating and stirring, adding ammonium persulfate, heating and stirring to obtain dispersion liquid E; and pouring the dispersion liquid E into a mold, placing the mold in an oven at 60-80 DEG C under a sealing condition, heating for 1.5-4 hours, cooling and solidifying to obtain the inorganic hydrated salt phase change gel material packaged by the triple network.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change materials, and specifically to a triple-network encapsulated inorganic hydrated salt phase change gel material and a preparation method thereof. Background Art

[0002] With the improvement of people's living standards and the rapid development of industry, the demand for energy by people is also increasing, and it has become increasingly important to find sustainable energy resources and reduce and recycle waste heat. Phase change materials (PCMs) are a kind of functional materials that can reversibly absorb and release thermal energy during the phase change process. Phase change heat storage systems based on phase change materials have been widely used in solar thermal utilization, industrial waste heat recovery, and thermal management of new energy batteries, etc.

[0003] Classified by material properties, phase change materials can be divided into organic phase change materials and inorganic phase change materials. Among them, inorganic hydrated salts have the advantages of high latent heat, low cost, high thermal conductivity, non-flammability, etc., and have been widely used in many fields. However, they are prone to phase separation, have poor thermal stability and chemical stability, and have corrosiveness. In addition, inorganic hydrated salts also have the problem of large supercooling degree. The supercooling phenomenon limits the utilization of their phase change heat storage, so it is necessary to add nucleating agents to adjust the supercooling degree of inorganic hydrated salts.

[0004] Hydrogel is a polymer with excellent hydrophilicity and a three-dimensional network structure, which can retain a large amount of water inside it. Inorganic hydrated salts are high-concentration electrolyte solutions in the molten state and have good compatibility with hydrophilic materials. Therefore, compounding hydrogel with inorganic hydrated salts can effectively improve the phase separation and leakage problems of hydrated salts. CN115678512A discloses an inorganic hydrated salt phase change gel material with CMC as the hydrogel network unit, whose phase change temperature meets the temperature requirements of thermophilic crops, and the material morphology remains in the gel state before and after phase change, and it is not easy to leak and phase separate. The content of hydrated salts loaded in traditional chemically cross-linked inorganic hydrated salt phase change gel materials is low, and the relative enthalpy value is low.

[0005] Therefore, inventing an inorganic hydrated salt phase change gel material with a simpler preparation method and good mechanical strength and elasticity will greatly broaden the application scope of inorganic hydrated salt phase change materials, which is of great significance to the research in the technical field of phase change materials. Summary of the Invention

[0006] The purpose of the present invention is to provide a triple-network encapsulated inorganic hydrated salt phase change gel material and a preparation method thereof to solve the problems proposed in the above background art.

[0007] To solve the above technical problems, the present invention provides the following technical solutions:

[0008] A preparation method of an inorganic hydrated salt phase change gel material encapsulated by a triple network, comprising the following steps:

[0009] Step 1: Heat and stir the inorganic hydrated salt and urea to obtain dispersion A;

[0010] Step 2: Add the nucleating agent to dispersion A, heat and stir to obtain dispersion B;

[0011] Step 3: Add acrylamide, sodium acrylate and an aqueous solution of polyvinyl alcohol to dispersion B, heat and stir to obtain dispersion D;

[0012] Step 4: Add N,N-methylenebisacrylamide to dispersion D, heat and stir, add ammonium persulfate, heat and stir to obtain dispersion E;

[0013] Step 5: Pour dispersion E into a mold, place it in an oven at 60-80°C under sealed conditions, heat for 1.5-4 h, cool and solidify to obtain the inorganic hydrated salt phase change gel material encapsulated by a triple network.

[0014] Further, the preparation method of the inorganic hydrated salt phase change gel material encapsulated by a triple network is characterized by comprising the following steps:

[0015] Step 1: Heat and stir the inorganic hydrated salt and urea to obtain dispersion A;

[0016] Step 2: Add the nucleating agent to dispersion A, heat and stir to obtain dispersion B;

[0017] Step 3: Add boron nitride material to dispersion B, heat and stir to obtain dispersion C;

[0018] Step 4: Add acrylamide, sodium acrylate and an aqueous solution of polyvinyl alcohol to dispersion C, heat and stir to obtain dispersion D;

[0019] Step 4: Add N,N-methylenebisacrylamide to dispersion D, heat and stir, add ammonium persulfate, heat and stir to obtain dispersion E;

[0020] Step 6: Pour dispersion E into a mold, place it in an oven at 60-80°C under sealed conditions, heat for 1.5-4 h, cool and solidify to obtain the inorganic hydrated salt phase change gel material encapsulated by a triple network.

[0021] Furthermore, the proportions of the components in the dispersion E, by mass, are 34-95 parts of inorganic hydrated salt, 0-20 parts of urea, 0.5-5 parts of nucleating agent, 1-10 parts of boron nitride material, 2-15 parts of acrylamide, 0.4-12 parts of sodium acrylate, 1-10 parts of polyvinyl alcohol aqueous solution, 0.05-0.3 parts of N,N-methylenebisacrylamide, and 0.01-0.15 parts of ammonium persulfate; wherein the concentration of the polyvinyl alcohol aqueous solution is 1-10wt%.

[0022] Furthermore, the inorganic hydrated salt includes any one of calcium chloride hexahydrate, sodium acetate trihydrate, sodium thiosulfate pentahydrate, and magnesium nitrate hexahydrate.

[0023] Furthermore, the nucleating agent includes any one of disodium hydrogen phosphate dodecahydrate, sodium silicate decahydrate, and sodium pyrophosphate decahydrate.

[0024] Furthermore, the boron nitride particle size is 0.1-45 μm.

[0025] Furthermore, the mass ratio of acrylamide:sodium acrylate is 1:(0.2-0.8).

[0026] Furthermore, in the step 1, step 2, step 3 and step 4, the water bath is heated to a temperature 10-20° C. higher than the melting point of the inorganic hydrated salt; in the step 5, the heating temperature is 40-60° C.

[0027] Furthermore, the method for preparing the polyvinyl alcohol aqueous solution comprises the following steps: adding polyvinyl alcohol powder to deionized water, heating to 92-98° C. and stirring for 35-120 min to obtain the polyvinyl alcohol aqueous solution; wherein the stirring rate is 500-800 rpm; the polyvinyl alcohol powder has a degree of alcoholysis of 98-100 mol% and a viscosity of 20-50 mpa·s.

[0028] Furthermore, the phase change temperature of the triple network encapsulated inorganic hydrated salt phase change gel material is 20-80°C.

[0029] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0030] The present invention utilizes the characteristics of inorganic hydrated salt phase-change materials, such as low price, non-flammability, high phase change enthalpy and thermal decomposition enthalpy, and combines the good gel properties of acrylamide and sodium acrylate to prepare phase-change gel; boron nitride is added during the preparation process to increase the thermal conductivity of the inorganic hydrated salt phase-change gel material; at the same time, polyvinyl alcohol aqueous solution is added during the preparation process to enhance the mechanical strength of the inorganic hydrated salt phase-change gel material, improve the water retention effect and prevent the gel from losing water.

[0031] The triple-network encapsulated inorganic hydrated salt phase change gel material prepared by the present invention has the advantages of excellent thermodynamic properties, good thermal stability, large phase change latent heat, low supercooling degree, and high thermal conductivity; at the same time, it has potential application scenarios in battery thermal management, building energy conservation, etc. Description of the Drawings

[0032] The 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. In the drawings:

[0033] Figure 1 It is a schematic diagram of strain-stress of the triple-network encapsulated inorganic hydrated salt phase change gel materials prepared in Example 4 and Comparative Example 1 at room temperature.

[0034] Figure 2 It is a schematic diagram of strain-stress of the triple-network encapsulated inorganic hydrated salt phase change gel materials prepared in Example 4 and Comparative Example 1 when heated at 60°C for 10 min.

[0035] Figure 3 It is a DSC diagram of the triple-network encapsulated inorganic hydrated salt phase change gel materials prepared in Example 1 and Example 4.

[0036] Figure 4 It is a schematic diagram of the thermal conductivity of the triple-network encapsulated inorganic hydrated salt phase change gel materials prepared in Example 1 and Example 6. Detailed Embodiments

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] It should be noted that there are no special restrictions on the purchase manufacturers of all raw materials involved in the present invention. Exemplarily, they include:

[0039] In the following embodiments, sodium acetate trihydrate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; sodium silicate decahydrate was purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; calcium chloride hexahydrate was purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; sodium thiosulfate pentahydrate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; disodium hydrogen phosphate dodecahydrate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; sodium pyrophosphate decahydrate was purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; boron nitride and polyvinyl alcohol powder were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; the rest of the raw materials were commercially available.

[0040] Example 1: A preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation: Step 1: Heat 72 g of sodium acetate trihydrate and 8 g of urea at 70 °C with stirring at 400 rpm for 1 h to obtain dispersion A;

[0041] Step 2: Add 2.4 g of melted disodium hydrogen phosphate dodecahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 15 min to obtain dispersion B;

[0042] Step 3: Add 8.75 g of acrylamide, 3.75 g of sodium acrylate, and 7.5 g of 5 wt% polyvinyl alcohol aqueous solution to dispersion B, heat at 60 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0043] Step 4: Add 0.2 g of N,N'-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.1 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 4 min to obtain dispersion E;

[0044] Step 5: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2 h, and cool and solidify to obtain an inorganic hydrated salt phase change gel material with triple network encapsulation.

[0045] Example 2: A preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation: Step 1: Heat 60 g of calcium chloride hexahydrate at 40 °C with stirring at 400 rpm for 1 h to obtain dispersion A;

[0046] Step 2: Add 3 g of melted sodium pyrophosphate decahydrate to dispersion A, heat at 40 °C with stirring at 400 rpm for 30 min to obtain dispersion B;

[0047] Step 3: Add 9 g of acrylamide, 3 g of sodium acrylate, and 8 g of 1 wt% polyvinyl alcohol aqueous solution to dispersion B, heat at 40 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0048] Step 4: Add 0.064 g of N,N'-methylenebisacrylamide to dispersion D, heat at 40 °C with stirring at 500 rpm for 15 min, add 0.06 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 6 min to obtain dispersion E;

[0049] Step 5: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2.5 h, and cool and solidify to obtain an inorganic hydrated salt phase change gel material with triple network encapsulation.

[0050] Example 3: A preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation: Step 1: Heat 61.8 g of sodium thiosulfate pentahydrate at 70 °C with stirring at 300 rpm for 1 h to obtain dispersion A;

[0051] Step 2: Add 2.2 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 300 rpm for 10 min to obtain dispersion B;

[0052] Step 3: Add 11 g of acrylamide, 2.2 g of sodium acrylate, and 5 g of 10 wt% polyvinyl alcohol aqueous solution to dispersion B, heat at 60 °C with stirring at 300 rpm for 25 min to obtain dispersion D;

[0053] Step 4: Add 0.18 g of N,N-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 300 rpm for 10 min, add 0.008 g of ammonium persulfate, and heat at 60 °C with stirring at 300 rpm for 2 min to obtain dispersion E;

[0054] Step 5: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2 h, and cool and solidify to obtain an inorganic hydrated salt phase change gel material with triple network encapsulation.

[0055] Example 4: A preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation: Step 1: Heat 72 g of sodium acetate trihydrate and 8 g of urea at 70 °C with stirring at 400 rpm for 1 h to obtain dispersion A;

[0056] Step 2: Add 2.4 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 15 min to obtain dispersion B;

[0057] Step 3: Add 10 g of boron nitride material with a diameter of 45 μm to dispersion B, heat at 70 °C with stirring at 400 rpm for 10 min to obtain dispersion C;

[0058] Step 4: Add 8.75 g of acrylamide, 3.75 g of sodium acrylate, and 7.5 g of 5 wt% polyvinyl alcohol aqueous solution to dispersion C, heat at 60 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0059] Step 5: Add 0.2 g of N,N-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.1 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 4 min to obtain dispersion E;

[0060] Step 6: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2 h, and cool and solidify to obtain an inorganic hydrated salt phase change gel material with triple network encapsulation.

[0061] Example 5: A preparation method of an inorganic hydrated salt phase change gel material encapsulated by a triple network: Step 1: Heat 64 g of sodium acetate trihydrate and 16 g of urea at 70 °C with stirring at 400 rpm for 0.75 h to obtain dispersion A;

[0062] Step 2: Add 1.6 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 20 min to obtain dispersion B;

[0063] Step 3: Add 1.5 g of boron nitride material with a diameter of 0.1 μm to dispersion B, heat at 70 °C with stirring at 400 rpm for 30 min to obtain dispersion C;

[0064] Step 4: Add 16 g of acrylamide, 5 g of sodium acrylate and 8 g of 3 wt% polyvinyl alcohol aqueous solution to dispersion C, heat at 60 °C with stirring at 600 rpm for 30 min to obtain dispersion D;

[0065] Step 5: Add 0.09 g of N,N - methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.05 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 20 min to obtain dispersion E;

[0066] Step 6: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2 h, and cool and solidify to obtain an inorganic hydrated salt phase change gel material encapsulated by a triple network.

[0067] Example 6: A preparation method of an inorganic hydrated salt phase change gel material encapsulated by a triple network: Step 1: Heat 80 g of sodium acetate trihydrate at 70 °C with stirring at 400 rpm for 1.25 h to obtain dispersion A;

[0068] Step 2: Add 1.2 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 15 min to obtain dispersion B;

[0069] Step 3: Add 5.5 g of boron nitride material with a diameter of 10 μm to dispersion B, heat at 70 °C with stirring at 400 rpm for 10 min to obtain dispersion C;

[0070] Step 4: Add 8 g of acrylamide, 4.5 g of sodium acrylate and 9.5 g of 1 wt% polyvinyl alcohol aqueous solution to dispersion C, heat at 60 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0071] Step 5: Add 0.2 g of N,N-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.1 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 2 min to obtain dispersion E;

[0072] Step 6: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2 h, cool and solidify to obtain a triple-network encapsulated inorganic hydrated salt phase change gel material.

[0073] Example 7: A preparation method of a triple-network encapsulated inorganic hydrated salt phase change gel material: Step 1: Heat 72 g of sodium acetate trihydrate and 8 g of urea at 70 °C with stirring at 400 rpm for 1 h to obtain dispersion A;

[0074] Step 2: Add 2.4 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 15 min to obtain dispersion B;

[0075] Step 3: Add 7 g of boron nitride material with a diameter of 25 μm to dispersion B, heat at 70 °C with stirring at 400 rpm for 10 min to obtain dispersion C;

[0076] Step 4: Add 11.7 g of acrylamide, 6 g of sodium acrylate, and 5.3 g of 5 wt% polyvinyl alcohol aqueous solution to dispersion C, heat at 75 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0077] Step 5: Add 0.25 g of N,N-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.07 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 15 min to obtain dispersion E;

[0078] Step 6: Pour dispersion E into a mold, place it in an oven at 65 °C under sealed conditions, heat for 3 h, cool and solidify to obtain a triple-network encapsulated inorganic hydrated salt phase change gel material.

[0079] Example 8: A preparation method of a triple-network encapsulated inorganic hydrated salt phase change gel material: Step 1: Heat 74.25 g of sodium acetate trihydrate and 8.25 g of urea at 70 °C with stirring at 400 rpm for 1 h to obtain dispersion A;

[0080] Step 2: Add 2 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 15 min to obtain dispersion B;

[0081] Step 3: Add 10 g of boron nitride material with a diameter of 45 μm to dispersion B, heat at 70 °C with stirring at 400 rpm for 10 min to obtain dispersion C;

[0082] Step 4: Add 7 g of acrylamide, 3 g of sodium acrylate, and 7.5 g of 7 wt% polyvinyl alcohol aqueous solution to dispersion C, heat at 60 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0083] Step 5: Add 0.3 g of N,N'-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.1 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 5 min to obtain dispersion E;

[0084] Step 6: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2.5 h, cool and solidify to obtain a triple-network encapsulated inorganic hydrated salt phase change gel material.

[0085] Comparative Example 1: A preparation method of a triple-network encapsulated inorganic hydrated salt phase change gel material: Step 1: Heat 72 g of sodium acetate trihydrate and 8 g of urea at 70 °C with stirring at 400 rpm for 1 h to obtain dispersion A;

[0086] Step 2: Add 2.4 g of melted sodium silicate decahydrate to dispersion A, heat at 70 °C with stirring at 400 rpm for 15 min to obtain dispersion B;

[0087] Step 3: Add 10 g of boron nitride material with a diameter of 45 μm to dispersion B, heat at 70 °C with stirring at 400 rpm for 10 min to obtain dispersion C;

[0088] Step 4: Add 8.75 g of acrylamide, 3.75 g of sodium acrylate, and 7.5 g of deionized water to dispersion C, heat at 60 °C with stirring at 400 rpm for 20 min to obtain dispersion D;

[0089] Step 5: Add 0.2 g of N,N'-methylenebisacrylamide to dispersion D, heat at 60 °C with stirring at 400 rpm for 10 min, add 0.1 g of ammonium persulfate, and heat at 60 °C with stirring at 400 rpm for 4 min to obtain dispersion E;

[0090] Step 6: Pour dispersion E into a mold, place it in an oven at 60 °C under sealed conditions, heat for 2 h, cool and solidify to obtain a triple-network encapsulated inorganic hydrated salt phase change gel material.

[0091] The test conditions for the above examples and comparative examples are as follows:

[0092] Phase change temperature and phase change enthalpy test: Use a differential scanning calorimeter (DSC) to test the phase change temperature and phase change enthalpy of the sample. The test conditions are under a nitrogen atmosphere, the test temperature is 10 - 80 °C, and the heating rate is 5 (K / min).

[0093] Stress-strain test: The dispersion E prepared in Example 4 and Comparative Example 1 was poured into a dumbbell-shaped mold (with a middle length × width × height of 80 mm × 10 mm × 4 mm), sealed and placed in an oven at 60 °C for 2 h to obtain a triple-network encapsulated inorganic hydrated salt phase change gel material. Using a desktop servo universal tensile testing machine, the tensile properties of the samples were tested at room temperature and after heating at 60 °C for 10 min respectively.

[0094] Thermal conductivity test: The dispersion E prepared in Example 1 and Example 6 was poured into two cylindrical molds with a diameter of 4 cm and a height of 1 cm, sealed and placed in an oven at 60 °C for 2 h to obtain sodium acetate trihydrate phase change gel. The gel was taken out of the oven and cooled and solidified. The thermal conductivity of the samples was measured at 25 °C using a HotDisk instrument, and the average value was taken after testing 3 times.

[0095] Table 1 DSC test data of the triple-network encapsulated inorganic hydrated salt phase change gel materials prepared in Examples 1-8 and Comparative Example 1

[0096]

[0097]

[0098] Conclusion: The triple-network encapsulated inorganic hydrated salt phase change gel material prepared in this application has the advantages of excellent thermodynamic properties, good thermal stability, large phase change latent heat, low supercooling degree, and large thermal conductivity.

[0099] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation, characterized in that: The following steps are involved: Step 1: Heat and stir the inorganic hydrated salt and urea to obtain a dispersion A; Step 2: adding a nucleating agent to dispersion A, heating and stirring, to obtain dispersion B; Step 3: adding acrylamide, sodium acrylate and polyvinyl alcohol aqueous solution to dispersion B, heating and stirring to obtain dispersion D; Step 4: Add N,N-methylenebisacrylamide to dispersion D, heat and stir, add ammonium persulfate, heat and stir to obtain dispersion E; Step 5: Pour the dispersion E into a mold, place it in a 60-80°C oven under sealing conditions, heat it for 1.5-4 hours, and cool it to solidify, thereby obtaining a triple network encapsulated inorganic hydrated salt phase change gel material.

2. The method for preparing a triple network encapsulated inorganic hydrated salt phase change gel material according to claim 1, characterized in that it comprises the following steps: Step 1: Heat and stir the inorganic hydrated salt and urea to obtain a dispersion A; Step 2: adding a nucleating agent to dispersion A, heating and stirring, to obtain dispersion B; Step 3: Add the boron nitride material to the dispersion B, heat and stir to obtain the dispersion C; Step 4: adding acrylamide, sodium acrylate and polyvinyl alcohol aqueous solution into dispersion C, heating and stirring to obtain dispersion D; Step 5: Add N,N-methylenebisacrylamide to dispersion D, heat and stir, add ammonium persulfate, heat and stir to obtain dispersion E; Step 6: Pour the dispersion E into a mold, place it in a 60-80°C oven under sealing conditions, heat it for 1.5-4 hours, and cool it to solidify to obtain a triple network encapsulated inorganic hydrated salt phase change gel material.

3. The preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation according to claim 2, characterized in that: The proportions of the components in the dispersion E, by weight, are 34-95 parts of inorganic hydrated salt, 0-20 parts of urea, 0.5-5 parts of nucleating agent, 1-10 parts of boron nitride material, 2-15 parts of acrylamide, 0.4-12 parts of sodium acrylate, 1-10 parts of polyvinyl alcohol aqueous solution, 0.05-0.3 parts of N,N-methylenebisacrylamide, and 0.01-0.15 parts of ammonium persulfate; wherein the concentration of the polyvinyl alcohol aqueous solution is 1-10wt%.

4. The preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation according to claim 2, characterized in that: The inorganic hydrated salt includes any one of calcium chloride hexahydrate, sodium acetate trihydrate, sodium thiosulfate pentahydrate, and magnesium nitrate hexahydrate; the nucleating agent includes any one of disodium hydrogen phosphate dodecahydrate, sodium silicate decahydrate, and sodium pyrophosphate decahydrate.

5. The preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation according to claim 2, characterized in that: The particle size of the boron nitride is 0.1-45 μm.

6. The preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation according to claim 2, characterized in that: The mass ratio of acrylamide to sodium acrylate is 1:(0.2-0.8).

7. The preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation according to claim 2, characterized in that: In the step 1, step 2, step 3 and step 4, the water bath is heated to a temperature 10-20° C. higher than the melting point of the inorganic hydrated salt; in the step 5, the heating temperature is 40-60° C.

8. The preparation method of an inorganic hydrated salt phase change gel material with triple network encapsulation according to claim 2, characterized in that: The phase change temperature of the triple network encapsulated inorganic hydrated salt phase change gel material is 20-80°C. 9 . The triple-network-encapsulated inorganic hydrated salt phase-change gel material prepared according to the method for preparing a triple-network-encapsulated inorganic hydrated salt phase-change gel material according to any one of claims 1 to 8 .

10. Application of the triple network encapsulated inorganic hydrated salt phase change gel material according to claim 9 in the field of thermal energy storage.

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