A ternary chlorinated salt heat storage material with both heat storage performance and corrosion resistance and a preparation method thereof

Abstract

This invention discloses a ternary chloride salt thermal storage material that balances thermal storage performance and corrosion resistance, along with its preparation method. The thermal storage material is obtained by adding metal and metal oxide nanoparticles to a ternary molten salt composed of sodium chloride, potassium chloride, and magnesium chloride. The thermal storage performance of the ternary molten salt is enhanced through the interaction between the nanoparticles and the chloride salt; simultaneously, the interaction between the nanoparticles and the corrosive surface of the alloy pipe forms a corrosion-resistant layer or consumes corrosive components, achieving automatic corrosion prevention; and new nanoparticles can be replenished in the thermal storage tank as needed based on their consumption. The ternary chloride salt thermal storage material prepared by this invention exhibits excellent thermal storage performance, strong corrosion resistance, and low price; moreover, its preparation method is simple, efficient, low-cost, and convenient to operate, effectively overcoming the shortcomings of traditional molten chloride salts, such as poor thermal performance and strong corrosivity, and can be used as a high-temperature thermal storage / heat transfer medium in concentrated solar power generation systems.

Description

Technical Field

[0001] This invention relates to the fields of thermal storage materials and material corrosion protection, specifically to a ternary chloride salt thermal storage material that balances thermal storage performance and corrosion resistance, and its preparation method. Background Technology

[0002] Molten salt, as a potential heat storage and heat transfer material, has the characteristics of high heat transfer coefficient, large energy storage density, good thermal stability and low production cost. It has broad application prospects in fields such as high-temperature industrial waste heat recovery, solar thermal utilization and nuclear energy.

[0003] Common molten salts include nitrates, carbonates, and chlorides. Nitrates are characterized by low corrosiveness, low viscosity, and low cost. However, their thermal stability is relatively poor, and they easily decompose at high temperatures, thus limiting their application under high-temperature conditions. Carbonates are characterized by high melting points, large latent heat of phase change, and low price. However, they have high viscosity in liquid conditions, which easily clogs pipes, thus limiting their application in concentrated solar power systems.

[0004] Compared to molten salts, chloride salts offer advantages such as higher decomposition temperatures, wider operating temperature ranges, abundant material sources, and lower costs. As solar thermal power generation systems evolve towards higher parameter specifications, the requirements for the operating temperature range of molten salts are gradually increasing. Mixed chloride salts are considered the most promising heat storage materials for next-generation concentrated solar power systems. However, currently, the use of mixed chloride salts as heat transfer and storage materials still suffers from problems such as low thermal conductivity, low specific heat capacity, and strong corrosivity.

[0005] Because mixed chloride salts generally suffer from low specific heat capacity and low thermal conductivity, they can lead to problems such as low heat storage density and slow heat storage and release rates in thermal storage systems. Furthermore, poor heat transfer can cause thermal stress, jeopardizing equipment safety. Therefore, improving the safety and performance of thermal storage systems depends on enhancing the thermophysical properties of molten salts. Adding metal and metal oxide nanoparticles to molten salts to alter their microstructure is considered an effective way to strengthen their heat storage / heat transfer performance.

[0006] On the other hand, the strong corrosiveness of chloride salts to alloy materials is also a key issue limiting their further application in concentrated solar power systems. In molten chloride salts, due to the dissolution of oxides within the molten salt, the alloy does not form an oxide film to inhibit corrosion during exposure, thus requiring higher levels of corrosion protection. Methods to mitigate the corrosion of alloy materials by molten chloride salts mainly include adding corrosion inhibitors and alloy modification. For example, adding magnesium metal to molten chloride salts to neutralize corrosive components can significantly reduce the corrosion rate. Establishing a thermodynamically stable and corrosion-resistant coating barrier on the alloy surface to prevent direct contact between the alloy and molten chloride salts can also significantly reduce the corrosion rate; however, these methods suffer from problems such as complex operation and high cost.

[0007] Therefore, it is of great practical significance to propose a molten salt thermal storage material with good thermal storage performance, low corrosivity, simple preparation method and convenient operation. Summary of the Invention

[0008] This invention provides a ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity, as well as its preparation method. It solves the problems of poor thermal conductivity, low thermal storage density, and strong corrosivity of existing chloride molten salts, and can be effectively applied to the field of energy storage technology in solar thermal power generation systems.

[0009] To solve the above problems, the solution adopted by the present invention is:

[0010] A ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity includes:

[0011] A ternary chloride thermal storage material is prepared by adding nanoparticles that enhance heat storage performance and weaken corrosion resistance to a traditional ternary mixed molten salt of sodium chloride, potassium chloride, and magnesium chloride through melt blending. The nanoparticles are replenished in the thermal storage tank as needed based on their consumption.

[0012] Preferably, the ternary molten salt, calculated by mass percentage, contains 14.0%–18.0% sodium chloride, 36.0%–40.0% potassium chloride, and 46.0%–50.0% magnesium chloride. Within the range of these mass percentages, the chloride molten salt exhibits good thermal stability and excellent thermophysical properties.

[0013] Preferably, the nanoparticles are one or more of Al2O3, MgO, and Mg nanoparticles. The type of nanoparticles not only enhances the thermophysical properties of the molten salt but also improves its corrosion resistance. The particle size of the nanoparticles is 50.0–100.0 nm. This particle size range provides a high specific surface area, increasing the heat storage density of the molten salt. Changing the microstructure of the molten salt improves heat transfer efficiency. The addition amount is 8.0%–10.0% of the total mass of the ternary chloride salt heat storage material. This total mass range of nanoparticles effectively promotes the formation of a protective corrosion layer, further improving the corrosion resistance of the molten salt.

[0014] Preferably, the consumption of the nanoparticles is determined by measuring the nanoparticle content using a dynamic light scattering instrument.

[0015] As a preferred improvement of the present invention, the supplementary method is to automatically open the feeding port at the top of the heat storage tank when the mass of the detected nanoparticles drops to 80.0%, add new nanoparticles with a mass percentage of 20.0% of the total mass of the added nanoparticles into the heat storage tank, and continuously stir.

[0016] A method for preparing a ternary chloride thermal storage material that combines thermal storage performance and corrosivity includes: taking a certain mass of different powdered single-component chloride salts and nanoparticles and drying them in a drying oven for a period of time; then, weighing each component chloride salt and nanoparticles according to the mass ratio using an electronic balance; physically mixing and stirring the three types of chloride salts and nanoparticles to obtain a composite chloride salt; then, heating the composite chloride salt in a muffle furnace to a high temperature, and after it is completely melted, continuously stirring and maintaining a constant temperature for a certain time; finally, turning off the muffle furnace to cool and solidify, and then grinding and drying the material to obtain a ternary chloride thermal storage material that combines thermal storage performance and corrosivity.

[0017] Preferably, the mixing method of the composite chloride salt refers to weighing the dried powdered single-component chloride salts according to the following proportions: sodium chloride 14.0%–18.0%, potassium chloride 36.0%–40.0%, and magnesium chloride 46.0%–50.0%; then weighing nanoparticles accounting for 8.0%–10.0% of the total mass of the three chloride salts and nanoparticles; and physically mixing and stirring the three chloride salts and nanoparticles to obtain the composite chloride salt.

[0018] As a preferred improvement of the present invention, the heating temperature and constant temperature conditions are 700℃~800℃, the continuous stirring time after melting is 1~2h, the constant temperature duration is 1~2h, and the cooling and solidification temperature is 20℃~40℃.

[0019] As a preferred improvement of the present invention, the drying process refers to placing a single-component chloride salt or a complex chloride salt under constant temperature and ventilation conditions and drying it at a temperature of 100-120°C for at least 20 hours.

[0020] As a preferred improvement of the present invention, the purity of the molten salt of the single-component sodium chloride, potassium chloride, and magnesium chloride is not less than 99%.

[0021] As a preferred improvement of the present invention, the purity of the nanoparticles is not less than 98%.

[0022] The nanoparticles described in this invention are required to be chemically stable and not react with chloride molten salt systems or metallic materials under working conditions. Al2O3 and MgO nanoparticles are preferred options.

[0023] Taking into account both the corrosion resistance and thermal properties of the nanofluid-mixed molten salt, the mass percentage of the nanoparticles is 10.0% of that of the ternary chloride salt thermal storage material.

[0024] The particle size of the nanoparticles is preferably 100 nm, and most preferably 50 nm. This is because smaller nanoparticles have a larger specific surface area and are more likely to combine with metal oxides produced by corrosion to form a protective layer and inhibit the diffusion of corrosive elements.

[0025] The optimal purity for nanoparticles is 99.9%. This is because high-purity nanoparticles typically have better crystal structure integrity and higher chemical stability, making them less likely to react chemically with other components, such as oxidizing substances in molten salts, thus accelerating the corrosion process.

[0026] During use, the molten salt of the present invention is typically in contact with conventional corrosion-resistant alloys in the art, including nickel-based alloys or iron-based alloys, specifically Inconel 625 nickel-based alloy.

[0027] Description of the invention principle:

[0028] Chloride molten salts possess chemical stability and a wide operating temperature range, making them the most promising heat storage materials for concentrated solar thermal power generation systems in high-temperature environments. However, their strong corrosiveness and relatively poor thermal properties severely limit their application. This invention addresses these issues by adding nanoparticles to ternary chloride molten salts, thus preparing a ternary chloride salt heat storage material that balances heat storage performance and corrosion resistance.

[0029] Detailed technical principle description:

[0030] Chloride molten salts contain corrosive impurities such as oxygen and water vapor at high temperatures. Water vapor reacts with hydrophilic chlorides in the chloride salt, such as magnesium chloride, to produce basic magnesium chloride and hydrogen chloride. On the other hand, oxygen oxidizes some chloride ions in the molten salt, producing chlorine gas. In summary, the chloride molten salt system exerts a combined effect of dissolution, oxidation, and chlorination on the alloy. These corrosive impurities accelerate the corrosion process of the alloy.

[0031] This invention adds nanoparticles to a ternary chloride molten salt system with sodium chloride, potassium chloride, and magnesium chloride as the main components. During the corrosion process, the nanoparticles diffuse into the corrosion interface where the chloride molten salt and the alloy material meet, reacting with other corrosion products to form a chemically inert protective layer, thereby blocking the diffusion of oxidizing gases.

[0032] Meanwhile, in the ternary chloride molten salt system, nanoparticles have a larger surface area in contact with the molten salt, increasing the effective area for energy exchange, enabling them to absorb and store more heat, and improving the specific heat capacity of the molten salt, thereby increasing the heat storage density. Furthermore, the interaction between nanoparticles and molten salt can improve the microstructure of the molten salt, forming an ordered and uniform arrangement, promoting heat transfer, and contributing to improved thermal conductivity and specific heat capacity.

[0033] Compared with the prior art, the advantages of the present invention are as follows:

[0034] This invention discloses a ternary chloride salt thermal storage material that balances thermal storage performance and corrosion resistance. The preparation process is simple, involving the uniform mixing, heating, stirring, cooling, and grinding of nanoparticles in molten chloride salt, facilitating large-scale industrial production. It is highly adaptable, with the preparation method suitable for different types and sizes of nanoparticles, allowing selection of the most appropriate nanoparticle type based on actual needs. Operation is convenient, as nanoparticles can be replenished in the storage tank as needed. The nanoparticles in this thermal storage material enhance the thermal conductivity and specific heat capacity of the ternary chloride molten salt while reducing its corrosiveness to metal containers and pipes, thus extending the service life of the alloy structure and reducing cost losses. In summary, this invention provides a reliable thermal storage material for next-generation concentrated solar thermal power generation systems. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. In the drawings:

[0036] Figure 1 A method for preparing a ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity;

[0037] Figure 2A schematic diagram illustrating the anti-corrosion principle of adding nanoparticles;

[0038] Figure 3 The mechanism of enhancing thermophysical properties by adding nanoparticles. Detailed Implementation

[0039] To ensure that those skilled in the art understand the features of this invention, the technical terms and expressions used in the specification and claims are explained and defined below.

[0040] The theories or mechanisms mentioned in this invention, whether right or wrong, should not limit the scope of this invention.

[0041] In this invention, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, and contents, are used for simplicity and convenience only. Therefore, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible secondary ranges and individual values ​​within those ranges.

[0042] In this invention, unless otherwise specified, the words "comprising," "including," and similar terms used throughout the specification and claims should be interpreted as including rather than excluding; that is, meaning "including but not limited to."

[0043] This invention does not list all the technical features of each embodiment. Therefore, as long as there is no logical contradiction in the combination of these features, the technical features of each embodiment can be arbitrarily combined, and all possible combinations are considered to be within the scope of this specification.

[0044] The present invention will now be described in detail with reference to specific embodiments.

[0045] Example 1: As Figure 1 As shown in the figure, this embodiment describes a method for preparing a ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity. The steps are as follows:

[0046] 1. Preparation of ternary chloride salts

[0047] Sodium chloride, potassium chloride, and magnesium chloride powders were placed separately in a drying oven at 120°C for 20 hours to remove moisture from the chloride salts. After cooling to room temperature, the samples were weighed using a high-precision electronic balance at a mass ratio of 15:39:46 and thoroughly mixed to obtain the ternary chloride salt.

[0048] 2. Preparation of ternary chloride salt thermal storage materials

[0049] In a dry air environment, 90.0 g of ternary chloride salt was weighed and 10.0 g of Al2O3 nanoparticles with a particle size of 50 nm were added. The mixture was stirred evenly with a glass rod. The mixed chloride salt was placed in a muffle furnace and statically heated to 800 °C until the solid was completely melted. Then, it was continuously stirred and kept at this temperature for 2 hours to form a homogeneous liquid. After cooling to 20 °C, the solidified ternary chloride salt thermal storage material was removed and ground into powder using a pestle. The powder was then placed in a drying oven and dried at 120 °C for 20 hours to obtain a ternary chloride salt thermal storage material that combines thermal storage performance and corrosion resistance.

[0050] 3. Supplement the corrosion test of nanoparticles

[0051] 100.0g of ternary chloride salt thermal storage material containing nanoparticles was placed in a thermal storage tank and heated to 700℃ in a muffle furnace, maintaining the temperature for 48 hours. The mass change of the nanoparticles in the thermal storage tank was monitored using a dynamic light scattering instrument. When the mass dropped to 8.0g, 2.0g of Al2O3 nanoparticles with a particle size of 50nm were added to the thermal storage tank through the feeding port. The stirring device was started to ensure that the newly added nanoparticles were mixed evenly with the molten salt.

[0052] Example 2: Figure 1 As shown in the figure, this embodiment describes a method for preparing a ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity. The steps are as follows:

[0053] 1. Preparation of ternary chloride salts

[0054] Sodium chloride, potassium chloride, and magnesium chloride powders were placed in a drying oven at 100°C and dried for 25 hours to remove moisture from the chloride salts. After cooling to room temperature, the samples were weighed using a high-precision electronic balance at a mass ratio of 14:36:50 and thoroughly mixed to obtain the ternary chloride salt.

[0055] 2. Preparation of ternary chloride sodium thermal storage materials

[0056] In a dry air environment, 90.0 g of ternary chloride salt was weighed, and 10.0 g of Al2O3 and Mg nanoparticles with a particle size of 100 nm were added. The mixture was stirred evenly with a glass rod. The mixed chloride salt was placed in a muffle furnace and statically heated to 750 °C until the solid was completely melted. Then, it was continuously stirred and kept at this temperature for 2 hours to form a homogeneous liquid. After cooling to 40 °C, the solidified ternary chloride salt thermal storage material was removed and ground into powder using a pestle. The powder was then placed in a drying oven and dried at 110 °C for 22 hours to obtain a ternary chloride salt thermal storage material that combines thermal storage performance and corrosion resistance.

[0057] 3. Supplement the corrosion test of nanoparticles

[0058] 100.0g of ternary chloride thermal storage material containing nanoparticles was placed in a thermal storage tank and heated to 700℃ in a muffle furnace, maintaining the temperature for 48 hours. The mass change of the nanoparticles in the thermal storage tank was monitored using a dynamic light scattering instrument. When the mass dropped to 8.0g, 2.0g of Al2O3 and Mg nanoparticles with a particle size of 100nm were added to the thermal storage tank through the feeding port. The stirring device was started to ensure that the newly added nanoparticles were mixed evenly with the molten salt.

[0059] Example 3: As Figure 1 As shown in the figure, this embodiment describes a method for preparing a ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity. The steps are as follows:

[0060] 1. Preparation of ternary chloride salts

[0061] Sodium chloride, potassium chloride, and magnesium chloride powders were placed separately in a drying oven at 110°C for 22 hours to remove moisture from the chloride salts. After cooling to room temperature, the samples were weighed using a high-precision electronic balance at a mass ratio of 18:36:46 and thoroughly mixed to obtain the ternary chloride salt.

[0062] 2. Preparation of ternary chloride salt thermal storage materials

[0063] In a dry air environment, 90.0 g of ternary chloride salt was weighed and 10.0 g of Mg nanoparticles with a particle size of 50 nm were added. The mixture was stirred evenly with a glass rod. The mixed chloride salt was placed in a muffle furnace and statically heated to 800 °C until the solid was completely melted. Then, it was continuously stirred and kept at this temperature for 2 hours to form a homogeneous liquid. After cooling to 30 °C, the solidified ternary chloride salt thermal storage material was removed and ground into powder using a pestle. The powder was then placed in a drying oven and dried at 100 °C for 25 hours to obtain a ternary chloride salt thermal storage material that combines thermal storage performance and corrosion resistance.

[0064] 3. Supplement the corrosion test of nanoparticles

[0065] 100.0g of ternary chloride thermal storage material containing nanoparticles was placed in a thermal storage tank and heated to 700℃ in a muffle furnace, maintaining the temperature for 48 hours. The mass change of the nanoparticles in the thermal storage tank was monitored using a dynamic light scattering instrument. When the mass dropped to 8.0g, 2.0g of Mg nanoparticles with a particle size of 50nm was added to the thermal storage tank through the feeding port. The stirring device was started to ensure that the newly added nanoparticles were mixed evenly with the molten salt.

[0066] Example 4: Figure 1 As shown in the figure, this embodiment describes a method for preparing a ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity. The steps are as follows:

[0067] 1. Preparation of ternary chloride salts

[0068] Sodium chloride, potassium chloride, and magnesium chloride powders were placed separately in a drying oven at 100°C and dried for 25 hours to remove moisture from the chloride salts. After cooling to room temperature, the samples were weighed using a high-precision electronic balance at a mass ratio of 14:40:46 and thoroughly mixed to obtain the ternary chloride salt.

[0069] 2. Preparation of ternary chloride salt thermal storage materials

[0070] In a dry air environment, 90.0 g of ternary chloride salt was weighed and 10.0 g of MgO nanoparticles with a particle size of 100 nm were added. The mixture was stirred evenly with a glass rod. The mixed chloride salt was placed in a muffle furnace and statically heated to 700 °C until the solid was completely melted. Then, it was continuously stirred and kept at this temperature for 2 hours to form a homogeneous liquid. After cooling to 25 °C, the solidified ternary chloride salt thermal storage material was removed and ground into powder using a pestle. The powder was then placed in a drying oven and dried at 100 °C for 25 hours to obtain a ternary chloride salt thermal storage material that combines thermal storage performance and corrosion resistance.

[0071] 3. Supplement the corrosion test of nanoparticles

[0072] 100.0g of ternary chloride salt thermal storage material containing nanoparticles was placed in a thermal storage tank and heated to 700℃ in a muffle furnace, maintaining the temperature for 48 hours. The mass change of the nanoparticles in the thermal storage tank was monitored using a dynamic light scattering instrument. When the mass dropped to 8.0g, 2.0g of MgO nanoparticles with a particle size of 100nm was added to the thermal storage tank through the feeding port. The stirring device was started to ensure that the newly added nanoparticles were mixed evenly with the molten salt.

[0073] The ternary chloride salt thermal storage material prepared by the above steps, which combines thermal storage performance and corrosiveness, has a simple preparation process. It can be completed by dispersing nanoparticles in molten chloride salt, mixing them evenly, heating, stirring, cooling, and grinding. It is easy to carry out large-scale industrial production. It has strong adaptability, and the preparation method can be adapted to different types and sizes of nanoparticles. The most suitable type of nanoparticle can be selected according to actual needs. It is also convenient to operate, and the nanoparticles can be replenished in the thermal storage tank at any time according to the consumption of nanoparticles.

[0074] In the above embodiments, the thermal storage performance of the ternary chloride salt with added nanoparticles is improved to a limited extent, with the thermal conductivity and specific heat capacity increasing by more than 5.0%; while the corrosivity is reduced to a limited extent, with the mass loss of the nickel-based alloy decreasing by more than 10.0%.

[0075] This invention adds nanoparticles to a ternary chloride molten salt system with sodium chloride, potassium chloride, and magnesium chloride as the main components. For example... Figure 2 As shown, during the corrosion process, nanoparticles diffuse into the corrosion interface where the chloride molten salt and alloy material meet, reacting with other corrosion products to form a chemically inert protective layer, thereby blocking the diffusion of oxidizing gases.

[0076] Meanwhile, in the ternary chloride molten salt system, nanoparticles have a larger surface area in contact with the molten salt, increasing the effective area for energy exchange, enabling them to absorb and store more heat, and improving the specific heat capacity of the molten salt, thereby increasing the heat storage density. Furthermore, the interaction between nanoparticles and molten salt can improve the microstructure of the molten salt, forming an ordered and uniform arrangement, promoting heat transfer, and contributing to improved heat conduction efficiency and specific heat capacity, such as... Figure 3 As shown.

[0077] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications, additions, or similar substitutions to the specific embodiments described, as long as they do not deviate from the invention or exceed the scope defined in the claims, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A ternary chloride salt thermal storage material that balances thermal storage performance and corrosivity, characterized in that, The heat storage material is prepared by adding nanoparticles that enhance heat storage performance and weaken corrosion resistance to a ternary mixed molten salt of sodium chloride, potassium chloride, and magnesium chloride through a melt blending method. During use, new nanoparticles are added to the heat storage tank as needed based on the consumption of nanoparticles, and the tank is continuously stirred. The ternary molten salt contains, by mass percentage, 14.0%–18.0% sodium chloride, 36.0%–40.0% potassium chloride, and 46.0%–50.0% magnesium chloride. The nanoparticles are metallic Mg; the amount of nanoparticles added is 8.0% to 10.0% of the total mass of the ternary chloride thermal storage material.

2. The ternary chloride salt thermal storage material according to claim 1, which balances thermal storage performance and corrosivity, is characterized in that, The nanoparticles have a particle size of 50.0~100.0 nm.

3. The ternary chloride salt thermal storage material according to claim 1, which combines thermal storage performance and corrosivity, is characterized in that, The new nanoparticles are replenished by automatically opening the feeding port at the top of the heat storage tank when the mass of the nanoparticles drops to 80.0%, adding new nanoparticles at a mass percentage of 20.0% of the total mass of the added nanoparticles, and continuously stirring.

4. The ternary chloride salt thermal storage material according to claim 1, which combines thermal storage performance and corrosivity, is characterized in that, The purity of the molten salts of single-component sodium chloride, potassium chloride, and magnesium chloride is not less than 99%; the purity of the nanoparticles is not less than 98%.

5. The method for preparing the ternary chloride salt thermal storage material that combines thermal storage performance and corrosivity as described in any one of claims 1 to 4, characterized in that, The thermal storage material is prepared by melt blending, which achieves good dispersibility and compatibility by mixing chloride salts and nanoparticles together at high temperature. The specific preparation method is as follows: a certain mass of different powdered single-component chloride salts and nanoparticles are placed in a drying oven and dried for a period of time; then, each component chloride salt and nanoparticle are weighed according to the mass ratio using an electronic balance; the three chloride salts and nanoparticles are physically mixed and stirred to obtain a composite chloride salt; then, the composite chloride salt is placed in a muffle furnace and heated to a high temperature. After it is completely melted, it is continuously stirred and kept at a constant temperature for a certain period of time; finally, the muffle furnace is turned off for cooling and solidification. After being taken out, it is ground and dried to obtain a ternary chloride salt thermal storage material that combines thermal storage performance and corrosion resistance. The heating temperature and constant temperature conditions are 700 ℃~800 ℃, the continuous stirring time after melting is 1~2 h, the constant temperature duration is 1~2 h, and the cooling and solidification temperature is 20 ℃~40 ℃.

6. The preparation method according to claim 5, characterized in that, The stirring method is purely mechanical stirring to ensure that the chloride salt and nanoparticles are mixed evenly; the grinding method is to use a pestle to crush the solidified ternary chloride salt heat storage material into powder.

7. The preparation method according to claim 5, characterized in that, The drying process refers to placing single-component chloride salts or complex chloride salts under constant temperature and ventilation conditions and drying them at a temperature of 100~120 ℃ for at least 20 h.

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