A wear-resistant phase change energy storage material and its preparation method

Abstract

This invention relates to a wear-resistant phase change energy storage material and its preparation method, belonging to the field of energy storage material technology. The invention uses hydrazine hydrate and a hydrothermal method to prepare a mixture of tetragonal zirconium oxide and cerium oxide through complexation, followed by calcination in high-purity oxygen to obtain a CeO2-ZrO2 mixture. This mixture exhibits good wear resistance, resulting in a longer service life for the prepared phase change energy storage material. The invention also prepares modified halloysite nanotubes using a combination of impregnation and microwave methods. Impregnation allows a mixture of graphene and yttrium oxide to be uniformly loaded onto the halloysite nanotubes, forming a composite material. Microwave heating allows for rapid and uniform heating of the sample, enabling better bonding of graphene and yttrium oxide on the halloysite nanotubes and the formation of stable chemical bonds among the three. Furthermore, the invention introduces titanium carbide into the phase change energy storage material, which significantly improves the overall hardness of the material, thereby enhancing its wear resistance.

Description

Technical Field

[0001] This invention belongs to the field of energy storage materials technology, and relates to a wear-resistant phase change energy storage material and its preparation method. Background Technology

[0002] Phase change materials (PCMs) are materials with special properties that can change their physical properties in response to changes in temperature or pressure. These materials can transform from one solid phase to another, or from one liquid phase to another, or even undergo a gaseous phase transition. PCMs possess reversible phase change characteristics, enabling them to absorb or release large amounts of heat energy during the phase change process. Therefore, they are widely used in energy storage, temperature control, and other fields.

[0003] Wear-resistant phase change energy storage materials (PCEs) retain the basic properties of PCEs while also possessing excellent wear resistance. These materials can maintain stable performance during long-term use, reducing performance degradation and failure caused by wear. As a novel material with unique properties, wear-resistant PCEs have broad application prospects in energy storage and temperature control. Summary of the Invention

[0004] The purpose of this invention is to provide a wear-resistant phase change energy storage material and its preparation method, which has the characteristics of wear resistance.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A wear-resistant phase change energy storage material, wherein the energy storage material has the following formulation by mass percentage: 50-60% CeO2-ZrO2 mixture, 20-30% modified halloysite nanotubes, 10-15% titanium carbide, 2-3% dispersant, and 2-3% coupling agent.

[0007] The preparation method of CeO2-ZrO2 mixture is as follows:

[0008] S1.1: Dissolve zirconium nitrate and cerium nitrate in deionized water, with a molar ratio of zirconium nitrate to cerium nitrate of 2:1, to prepare a solution with a metal concentration of 0.1 mol / L. Sonicate the solution for 0.5 h to obtain mixed solution A.

[0009] S1.2: Add hydrazine hydrate to mixed solution A, wherein the molar ratio of hydrazine hydrate to metal element is 6:1. Stir at 140 r / min while adding, and continue sonication for 0.5 h after stirring to obtain mixed solution B.

[0010] S1.3: Add 1 wt% of diethanolamine and polyethylene glycol-2000 mixture to solution B and continue stirring at 140 r / min to obtain mixed solution C. Transfer mixed solution C to an autoclave with a filling degree of 80% and perform hydrothermal treatment at 140℃ for 12 h to obtain mixed solution D.

[0011] S1.4: The mixed solution D was centrifuged at 2500 rpm, filtered, and dried at 80℃ for 12 h to obtain solid E;

[0012] S1.5: Solid E is placed in a muffle furnace and calcined in a high-purity oxygen atmosphere for 3 hours at a temperature of 400°C. After calcination, it is cooled to room temperature and ground in a ball mill at a speed of 300 r / min for 1 hour to obtain the CeO2-ZrO2 mixture.

[0013] The method for preparing modified halloysite nanotubes is as follows.

[0014] S2.1: Graphene and yttrium oxide are mixed at a mass ratio of 10:1 and ground in a ball mill at a speed of 400 r / min for 0.5 h to obtain mixture F;

[0015] S2.2: Disperse mixture F in an ethanol solution and sonicate for 0.5 h to obtain a uniformly dispersed suspension G;

[0016] S2.3: Immerse halloysite nanotubes in suspension G, wherein the mass ratio of halloysite nanotubes to mixture F is 1:1, and stir at a speed of 140 r / min for 12 h to obtain solid-liquid mixture H;

[0017] S2.4: The solid-liquid mixture H is heated at a microwave power of 1000W for 30s, and then cooled to room temperature after microwave heat treatment to obtain solid I;

[0018] S2.5: Solid I is washed with deionized water at room temperature, then dried at 80°C for 6 hours. After drying, it is ground to a particle size of 200 mesh to obtain the modified halloysite nanotubes.

[0019] Furthermore, the dispersant is polyethylene glycol with a molecular weight of 2000-4000.

[0020] Furthermore, the coupling agent is one of vinyltriethoxysilane and vinyltri-β-methoxyethoxysilane.

[0021] Furthermore, the particle size of the solid obtained by grinding in S1.5 is 150 mesh.

[0022] A method for preparing a wear-resistant phase change energy storage material, the specific process of which is as follows:

[0023] S5.1: The CeO2-ZrO2 mixture, modified halloysite nanotubes, titanium carbide, dispersant and coupling agent were put into a ball mill according to the formula ratio and ground. The ball mill speed was 400 r / min and the grinding time was 2 h to obtain mixture J.

[0024] S5.2: The mixture J is placed in a mold and sintered at 400°C for 3 hours. After sintering, nitrogen is used to purge the mixture and the mixture is cooled to room temperature to obtain the energy storage material.

[0025] Furthermore, the particle size of the mixture J obtained by grinding in S5.1 is 150 mesh.

[0026] Furthermore, the flow rate of nitrogen in step S5.2 is 15 m / s.

[0027] Furthermore, in step S5.2, the temperature is cooled to room temperature at a rate of 3°C / s.

[0028] In the CeO2-ZrO2 mixture prepared in this invention, ZrO2 is tetragonal zirconium oxide. During the preparation process, zirconium nitrate and cerium nitrate are first dissolved simultaneously in deionized water to form the corresponding salt solutions. Then, hydrazine hydrate (N2H4·H2O) is added as a complexing agent, which reacts with zirconium ions (ZrO2- ... 4+ ) and cerium ions (Ce) 3+ / Ce 4+ Complex clusters are formed. This complexation helps control the hydrothermal growth process of zirconium oxide and cerium oxide and may reduce their size. In this invention, diethanolamine and polyethylene glycol-2000 are added as complexing aids, making the hydrothermal reaction more stable. The solution containing the complex clusters is placed in an autoclave and subjected to hydrothermal treatment at 140°C. The strong reducing power of hydrazine hydrate and the high temperature and pressure conditions of the hydrothermal treatment jointly promote the hydrolysis reaction of the complex clusters, generating a mixture of tetragonal zirconium oxide and cerium oxide nanoparticles. The nanoscale tetragonal zirconium oxide and cerium oxide particles prepared by the hydrothermal method have a large specific surface area and interface effect, which is beneficial to ion transport and energy conversion processes in energy storage materials. Due to the nanoscale size effect, the tetragonal zirconium oxide and cerium oxide nanoparticles prepared by the hydrothermal method exhibit good wear resistance, which enables the mixture to have a longer service life and better reliability in energy storage material applications.

[0029] Calcining a mixture of tetragonal zirconium oxide and cerium oxide prepared by hydrothermal method in high-purity oxygen can further stabilize its crystal structure and improve its physical and chemical properties. In addition, the high-purity oxygen environment also helps to remove impurities from the mixture and improve its purity.

[0030] Tetragonal zirconium oxide and cerium oxide are both high-energy-density materials, and their mixtures exhibit even higher energy storage capacity. The addition of cerium oxide can improve the ionic conductivity of tetragonal zirconium oxide, resulting in better performance of the mixture in energy storage material applications. Furthermore, tetragonal zirconium oxide and cerium oxide in the mixture also produce a synergistic effect, because the ionic radius of cerium oxide is similar to that of Zr... 4+ The similarity between the two allows them to form a stable solid solution; and as an ionic conductor, cerium oxide can improve the ionic conductivity of zirconium oxide, while zirconium oxide can improve the structural stability of the mixture. Through mutual complementarity and enhancement, the overall performance of the energy storage material is further improved.

[0031] This invention also prepared modified halloysite nanotubes by combining impregnation and microwave methods. Graphene, as a high-performance two-dimensional material, has extremely high electrical conductivity and specific surface area. Mixing it with yttrium oxide and loading it onto halloysite nanotubes can further improve its energy density, making it an excellent energy storage material. Halloysite nanotubes have unique structural properties, such as high surface area, special pore structure, and structural stability. These characteristics help stabilize the mixture of graphene and yttrium oxide, thereby enhancing the stability of the entire energy storage system. Furthermore, loading the mixture of graphene and yttrium oxide onto halloysite nanotubes can optimize the ion transport path in the material, improving ion transport rate and efficiency.

[0032] A mixture of graphene and yttrium oxide can be uniformly loaded onto halloysite nanotubes via an impregnation method, forming a stable composite material. This composite material combines the high conductivity of graphene and the stability of yttrium oxide with the unique structural advantages of halloysite nanotubes. Microwave heating allows for rapid and uniform heating of the sample, leading to better bonding of graphene and yttrium oxide onto the halloysite nanotubes. The microwave method also facilitates the formation of carbon-oxygen bonds between graphene and yttrium oxide, enhancing their bonding strength. Furthermore, graphene and yttrium oxide react with the hydroxyl groups on the halloysite nanotubes to form stable chemical bonds, further optimizing the performance of the phase change energy storage material.

[0033] When titanium carbide is added to phase change energy storage materials, it can significantly increase the overall hardness of the material, thereby improving its wear resistance. The addition of titanium carbide can strengthen the crystal structure and lattice of the phase change energy storage material, improving its mechanical properties. This enhanced crystal structure helps resist external wear, improving the material's wear resistance. In this invention, a CeO2-ZrO2 mixture, modified halloysite nanotubes, titanium carbide, dispersant, and coupling agent are sintered through grinding and sintering to obtain the final wear-resistant phase change energy storage material.

[0034] The beneficial effects of this invention are:

[0035] This invention uses hydrazine hydrate and prepares a mixture of tetragonal zirconium oxide and cerium oxide through a hydrothermal method via complexation. The mixture is then calcined in high-purity oxygen to obtain a CeO2-ZrO2 mixture. This mixture exhibits good wear resistance in terms of physical properties, which enables the mixture to have a longer service life and better reliability in energy storage material applications.

[0036] This invention prepares modified halloysite nanotubes by combining impregnation and microwave methods. The impregnation method allows a mixture of graphene and yttrium oxide to be uniformly loaded onto halloysite nanotubes, forming a stable composite material. The microwave method can rapidly and uniformly heat the sample, allowing graphene and yttrium oxide to better bond on the halloysite nanotubes and form stable chemical bonds among the three, further optimizing the performance of the phase change energy storage material.

[0037] This invention also introduces titanium carbide into the phase change energy storage material, which can significantly improve the overall hardness of the material, thereby improving its wear resistance. Detailed Implementation

[0038] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0039] Formula ratio 1: CeO2-ZrO2 mixture 60%, modified halloysite nanotubes 20%, titanium carbide 15%, PEG-2000 2%, vinyltriethoxysilane 3%;

[0040] Formula ratio 2: CeO2-ZrO2 mixture 50%, modified halloysite nanotubes 30%, titanium carbide 15%, PEG-2000 3%, vinyltri-β-methoxyethoxy-silane 2%;

[0041] Formula ratio 3: CeO2-ZrO2 mixture 60%, modified halloysite nanotubes 25%, titanium carbide 10%, PEG-4000 3%, vinyltriethoxysilane 2%;

[0042] The preparation method of CeO2-ZrO2 mixture is as follows:

[0043] S1.1: Dissolve zirconium nitrate and cerium nitrate in deionized water, with a molar ratio of zirconium nitrate to cerium nitrate of 2:1, to prepare a solution with a metal concentration of 0.1 mol / L. Sonicate the solution for 0.5 h to obtain mixed solution A.

[0044] S1.2: Add hydrazine hydrate to mixed solution A, wherein the molar ratio of hydrazine hydrate to metal element is 6:1. Stir at 140 r / min while adding, and continue sonication for 0.5 h after stirring to obtain mixed solution B.

[0045] S1.3: Add 1 wt% of diethanolamine and polyethylene glycol-2000 mixture to solution B and continue stirring at 140 r / min to obtain mixed solution C. Transfer mixed solution C to an autoclave with a filling degree of 80% and perform hydrothermal treatment at 140℃ for 12 h to obtain mixed solution D.

[0046] S1.4: The mixed solution D was centrifuged at 2500 rpm, filtered, and dried at 80℃ for 12 h to obtain solid E;

[0047] S1.5: Solid E is placed in a muffle furnace and calcined in a high-purity oxygen atmosphere for 3 hours at a temperature of 400°C. After calcination, it is cooled to room temperature and ground in a ball mill at a speed of 300 r / min for 1 hour to obtain the CeO2-ZrO2 mixture with a particle size of 150 mesh.

[0048] The method for preparing modified halloysite nanotubes is as follows.

[0049] S2.1: Graphene and yttrium oxide are mixed at a mass ratio of 10:1 and ground in a ball mill at a speed of 400 r / min for 0.5 h to obtain mixture F;

[0050] S2.2: Disperse mixture F in an ethanol solution and sonicate for 0.5 h to obtain a uniformly dispersed suspension G;

[0051] S2.3: Immerse halloysite nanotubes in suspension G, wherein the mass ratio of halloysite nanotubes to mixture F is 1:1, and stir at a speed of 140 r / min for 12 h to obtain solid-liquid mixture H;

[0052] S2.4: The solid-liquid mixture H is heated at a microwave power of 1000W for 30s, and then cooled to room temperature after microwave heat treatment to obtain solid I;

[0053] S2.5: Solid I is washed with deionized water at room temperature, then dried at 80°C for 6 hours. After drying, it is ground to a particle size of 200 mesh to obtain the modified halloysite nanotubes.

[0054] Example 1

[0055] S5.1: The CeO2-ZrO2 mixture, modified halloysite nanotubes, titanium carbide, dispersant and coupling agent are put into a ball mill for grinding according to the formula ratio 1. The ball mill speed is 400 r / min and the grinding time is 2h to obtain mixture J. The particle size of mixture J is 150 mesh.

[0056] S5.2: The mixture J is placed in a mold and sintered at 400°C for 3 hours. After sintering, nitrogen is used to purge the mixture at a flow rate of 15 m / s and then cooled to room temperature at a rate of 3°C / s to obtain the energy storage material.

[0057] Example 2

[0058] S5.1: The CeO2-ZrO2 mixture, modified halloysite nanotubes, titanium carbide, dispersant and coupling agent are put into a ball mill at the formula ratio 2 and ground. The ball mill speed is 400 r / min and the grinding time is 2h to obtain mixture J. The particle size of mixture J is 150 mesh.

[0059] S5.2: The mixture J is placed in a mold and sintered at 400°C for 3 hours. After sintering, nitrogen is used to purge the mixture at a flow rate of 15 m / s and then cooled to room temperature at a rate of 3°C / s to obtain the energy storage material.

[0060] Example 3

[0061] S5.1: The CeO2-ZrO2 mixture, modified halloysite nanotubes, titanium carbide, dispersant and coupling agent are put into a ball mill at the formula ratio of 3 and ground. The ball mill speed is 400 r / min and the grinding time is 2 h to obtain mixture J. The particle size of mixture J is 150 mesh.

[0062] S5.2: The mixture J is placed in a mold and sintered at 400°C for 3 hours. After sintering, nitrogen is used to purge the mixture at a flow rate of 15 m / s and then cooled to room temperature at a rate of 3°C / s to obtain the energy storage material.

[0063] Comparative Example 1

[0064] In this comparative example, the prepared CeO2-ZrO2 mixture is not used; only ZrO2 is used. The remaining steps are the same as in Example 1.

[0065] Comparative Example 2

[0066] In this comparative example, the CeO2-ZrO2 mixture is not calcined using high-purity oxygen; the remaining steps are the same as in Example 1.

[0067] Comparative Example 3

[0068] In this comparative example, no modified halloysite nanotubes were used; only ordinary halloysite nanotubes were used. The remaining steps were the same as in Example 1.

[0069] Comparative Example 4

[0070] In this comparative example, no yttrium oxide was added to the modified halloysite nanotubes, and the remaining steps were the same as in Example 1.

[0071] Comparative Example 5

[0072] In this comparative example, the modified halloysite nanotubes were not treated with microwaves, and the remaining steps were the same as in Example 1.

[0073] Comparative Example 6

[0074] Titanium carbide was not added in this comparative example, and the remaining steps were the same as in Example 1.

[0075] The wear resistance of the embodiments and comparative examples was tested using a JM IV abrasion tester and the rotating friction rubber wheel method. The wear resistance of the invention was measured by the average value of the coating mass loss (weight loss method) after 100 grinding revolutions. The applied load was 10 N, the rotation speed was 80 r / min, the test temperature was 25 °C, and the relative humidity was 40%. The mass was measured to an accuracy of 0.01 mg, and the average value of three measurements was taken as the result.

[0076] The initial thermal conductivity of the phase change energy storage material and its performance after 100 thermal cycles were measured using a thermal conductivity meter in both the examples and comparative cases.

[0077] The experimental data are summarized in the table below.

[0078]

[0079] As can be seen from the examples and comparative examples, the addition of CeO2-ZrO2 mixture, modified halloysite nanotubes, and titanium carbide all improve the wear resistance of the prepared phase change energy storage material, which can effectively improve its service life. It can also be seen from the examples and comparative examples that the addition of CeO2-ZrO2 mixture and modified halloysite nanotubes also improves the stability of the phase change energy storage material.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A wear-resistant phase change energy storage material, characterized in that, The energy storage material formulation is as follows, by mass percentage: 50-60% CeO2-ZrO2 mixture, 20-30% modified halloysite nanotubes, 10-15% titanium carbide, 2-3% dispersant, and 2-3% coupling agent. The preparation method of CeO2-ZrO2 mixture is as follows: S1.1: Dissolve zirconium nitrate and cerium nitrate in deionized water, with a molar ratio of zirconium nitrate to cerium nitrate of 2:1, to prepare a solution with a metal concentration of 0.1 mol / L. Sonicate the solution for 0.5 h to obtain mixed solution A. S1.2: Add hydrazine hydrate to mixed solution A, wherein the molar ratio of hydrazine hydrate to metal element is 6:

1. Stir at 140 r / min while adding, and continue sonication for 0.5 h after stirring to obtain mixed solution B. S1.3: Add 1 wt% of diethanolamine and polyethylene glycol-2000 mixture to solution B and continue stirring at 140 r / min to obtain mixed solution C. Transfer mixed solution C to an autoclave with a filling degree of 80% and perform hydrothermal treatment at 140℃ for 12 h to obtain mixed solution D. S1.4: The mixed solution D was centrifuged at 2500 rpm, filtered, and dried at 80℃ for 12 h to obtain solid E; S1.5: Solid E is placed in a muffle furnace and calcined in a high-purity oxygen atmosphere for 3 hours at a temperature of 400°C. After calcination, it is cooled to room temperature and ground in a ball mill at a speed of 300 r / min for 1 hour to obtain the CeO2-ZrO2 mixture. The method for preparing modified halloysite nanotubes is as follows. S2.1: Graphene and yttrium oxide are mixed at a mass ratio of 10:1 and ground in a ball mill at a speed of 400 r / min for 0.5 h to obtain mixture F; S2.2: Disperse mixture F in an ethanol solution and sonicate for 0.5 h to obtain a uniformly dispersed suspension G; S2.3: Immerse halloysite nanotubes in suspension G, wherein the mass ratio of halloysite nanotubes to mixture F is 1:1, and stir at a speed of 140 r / min for 12 h to obtain solid-liquid mixture H; S2.4: The solid-liquid mixture H is heated at a microwave power of 1000W for 30s, and then cooled to room temperature after microwave heat treatment to obtain solid I; S2.5: Solid I is washed with deionized water at room temperature, then dried at 80°C for 6 hours. After drying, it is ground to a particle size of 200 mesh to obtain the modified halloysite nanotubes.

2. The wear-resistant phase change energy storage material according to claim 1, characterized in that, The dispersant is polyethylene glycol with a molecular weight of 2000-4000.

3. The wear-resistant phase change energy storage material according to claim 1, characterized in that, The coupling agent is one of vinyltriethoxysilane and vinyltri-β-methoxyethoxysilane.

4. The wear-resistant phase change energy storage material according to claim 1, characterized in that, The solid particle size obtained by grinding in S1.5 is 150 mesh.

5. A method for preparing a wear-resistant phase change energy storage material, based on the wear-resistant phase change energy storage material according to any one of claims 1 to 4, characterized in that, The specific process for preparing the energy storage material is as follows. S5.1: The CeO2-ZrO2 mixture, modified halloysite nanotubes, titanium carbide, dispersant and coupling agent were put into a ball mill according to the formula ratio and ground. The ball mill speed was 400 r / min and the grinding time was 2 h to obtain mixture J. S5.2: The mixture J is placed in a mold and sintered at 400°C for 3 hours. After sintering, nitrogen is used to purge the mixture and the mixture is cooled to room temperature to obtain the energy storage material.

6. The method for preparing a wear-resistant phase change energy storage material according to claim 5, characterized in that, The particle size of the mixture J obtained by grinding in S5.1 is 150 mesh.

7. The method for preparing a wear-resistant phase change energy storage material according to claim 5, characterized in that, The flow rate of nitrogen in S5.2 is 15 m / s.

8. The method for preparing a wear-resistant phase change energy storage material according to claim 5, characterized in that, In step S5.2, the temperature is cooled to room temperature at a rate of 3°C / s.

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