High-temperature heat-insulating aerogel as well as preparation method and application thereof

Abstract

The invention relates to the technical field of aerogel, and discloses high-temperature heat-insulating aerogel as well as a preparation method and application thereof. The aerogel comprises a hydrophobic fiber material and the following substances in parts by weight: 20-40 parts of a silicon source, 40-50 parts of a solvent, 1-5 parts of a catalyst, 1-10 parts of a phase change material, 1-10 parts of an opacifying agent and 5-10 parts of an alkaline solution, wherein the ratio of the volume of the hydrophobic fiber material to the sum of the volumes of the silicon source, the solvent, the catalyst and the alkaline solution is 1: (1.1-1.5). The high-temperature heat insulation degree per millimeter of the obtained product reaches 144 DEG C or above.

Description

Technical Field

[0001] The present invention relates to the technical field of aerogels, and in particular to a high-temperature heat-insulating aerogel and a preparation method and application thereof. Background Art

[0002] Ceramic fiber aerogel has excellent high elasticity, high compressive strength, excellent temperature resistance and thermal insulation properties, which solves the problems of high brittleness of traditional aerogel and high thermal conductivity in high temperature environment. It is widely used in thermal insulation materials in the fields of building energy conservation, aerospace, etc. It is also expected to be used in battery cell insulation materials (designed to be in direct contact with the battery cell to improve the thermal conductivity of the battery cell, while isolating the electrical connection between different battery cells to avoid safety issues such as short circuit and fire).

[0003] The invention patent application with the publication number CN113731308A discloses a method for preparing a ceramic fiber paper-silicon aerogel insulation composite material, and provides a method for pretreating the ceramic fiber paper and adding a silicon source to obtain a high-strength insulation composite material with excellent insulation performance at both room temperature and high temperature. The invention patent application with the publication number CN113943171A discloses a method for preparing a silica aerogel ceramic fiber felt, and provides a step for high-temperature treatment of the ceramic fiber to improve the insulation performance and strength.

[0004] However, the high-temperature thermal insulation performance of the ceramic aerogel produced by the above method still cannot meet the thermal insulation requirements of the battery cells. At present, the thermal insulation performance of the ceramic fiber aerogel material used in the actual application of battery insulation is particularly reduced when subjected to a high-pressure environment. Therefore, it is particularly necessary to develop ceramic aerogel materials with good high-temperature thermal insulation performance. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to improve the high-temperature thermal insulation performance of ceramic fiber aerogel under a high-pressure environment.

[0006] In view of the above problems, the present invention provides a high-temperature insulating aerogel, comprising a hydrophobic fiber material and a material composition calculated in the following weight parts: 20-40 parts of a silicon source, 40-50 parts of a solvent, 1-5 parts of a catalyst, 1-10 parts of a phase change material, 1-10 parts of a sunscreen, and 5-10 parts of an alkaline solution; wherein the ratio of the volume of the hydrophobic fiber material to the sum of the volumes of the silicon source, the solvent, the catalyst, and the alkaline solution is 1:(1.1-1.5).

[0007] In a possible implementation, the hydrophobic fiber material is selected from one or more of aluminum silicate ceramic fiber paper, glass fiber wet-laid mat, and non-woven fabric.

[0008] And / or, the silicon source is selected from one or more of tetraethyl orthosilicate, ethyl silicate, triethoxysilane, methyl silicate, and trimethylethoxysilane; And / or, the solvent is selected from one or more of methanol, ethanol, ethyl ester, propanol, and ethylene glycol; And / or, the catalyst is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid solution; And / or, the phase change material is selected from one or more of aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; And / or, the sunscreen is selected from one or more of titanium dioxide, zinc oxide, carbon black, and kaolin; And / or, the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water.

[0009] In the above scheme, the increase in silicon content helps to enhance the chemical bonding inside the ceramic aerogel, improve the stability of the microstructure, and enable the ceramic aerogel to better maintain structural integrity when subjected to external stress, thereby effectively improving the strength of the ceramic aerogel. The above-mentioned silicon sources can react well with the hydrophobic fiber material matrix to better meet the thermal insulation performance requirements. The phase change material is made of metal hydroxides. The addition of these materials can absorb heat and undergo phase change when the battery operating temperature rises, dehydrate at high temperature, thereby delaying the transfer of heat to the surrounding environment, and further enhancing the thermal insulation performance of the entire thermal insulation structure. The addition of sunscreen increases infrared blocking and improves thermal insulation performance. The ceramic aerogel material obtained in this way has good high-temperature thermal insulation performance under high-pressure environments.

[0010] The present invention also provides a method for preparing a high-temperature heat-insulating aerogel, comprising the following steps: Step 1: pre-treating the hydrophobic fiber material at high temperature to remove organic matter; Step 2: Mix and hydrolyze the silicon source, solvent and catalyst, then add phase change material, sunscreen and alkaline solution to the hydrolyzate, stir evenly and pour on the product obtained in step 1 to form a composite wet gel; Step 3, mixing the composite wet gel and the hydrophilic organic reagent in a volume ratio of 1:1-1:10, and heating and aging in a water bath; Step 4: Clean and dry the product obtained in step 3 to obtain high-temperature thermal insulation ceramic aerogel.

[0011] The above method has the following advantages compared with the prior art: An additional silicon source, phase change material, and light-shielding agent are added to the hydrophobic fiber material treated at high temperature to form a composite wet gel. The high-temperature pretreatment can promote the decomposition and volatilization of the organic matter inside the hydrophobic fiber substrate, thereby effectively reducing its organic matter content, and then significantly improving the overall heat insulation performance of the material, enabling more effective blocking of heat diffusion during the heat transfer process. After adding the silicon source, the silicon content of the aerogel is increased, which can improve the strength of the material and meet the mechanical property requirements during application. Adding a phase change material can utilize the energy storage effect of the phase change material to improve the heat insulation effect of the aerogel and enhance the stability and reliability of the heat insulation performance. Adding a light-shielding agent can effectively reflect, scatter, and absorb radiant heat, significantly improving the heat insulation performance under high-temperature conditions. After aging treatment, the heat insulation performance of the material is better. Step four preferably uses the supercritical drying method to clean and dry the product obtained in step three to obtain the product.

[0012] In a possible implementation manner, the high-temperature treatment in step one is to heat the hydrophobic fiber material to 100 - 500 °C and keep it warm for 0.5 - 5 h.

[0013] In the above solution, the high-temperature pretreatment can promote the decomposition and volatilization of the organic matter inside the hydrophobic fiber material, thereby effectively reducing its organic matter content, and then significantly improving the overall heat insulation performance of the material, enabling more effective blocking of heat diffusion during the heat transfer process.

[0014] In a possible implementation manner, the specific operation of step two is to mix the solvent and the catalyst and heat it up to 30 - 80 °C, adjust the pH of the solution to 1 - 7, then add the silicon source, hydrolyze it at 40 - 80 °C for 0.5 - 24 h, cool it to room temperature, add the phase change material and the light-shielding agent and stir at high speed, then add the alkaline solution and stir evenly, and finally pour it onto the pretreated hydrophobic fiber material to form a composite wet gel.

[0015] Preferably, the solvent and the catalyst are mixed and heated up to 30 - 80 °C, and the silicon source is added after adjusting the pH of the solution to 2 - 5.

[0016] The control conditions of temperature, time, and pH value in the above process are all preferred conditions for the preparation of the aerogel of the present invention. Under these conditions, the composition and structure of the obtained wet gel are well controlled and can meet the requirements of the final product.

[0017] In a possible implementation manner, the water-soluble organic reagent in step three is selected from one or more of methanol, ethanol, ethyl acetate, propanol, and ethylene glycol; And / or, the temperature of the water bath heating and aging in step three is 40 - 70 °C, and the time is 0.5 - 12 h.

[0018] In the above solution, the addition of hydrophilic organic solvents can accelerate the precipitation of ions in the gel during the aging process, thereby affecting the function of the gel.

[0019] In a possible implementation, the cleaning and drying in step four are carried out by supercritical drying method.

[0020] In a possible implementation, the operation of the cleaning and drying by supercritical drying method is carbon dioxide supercritical drying, with a temperature of 30 - 70 °C and a pressure of 5 - 16 MPa.

[0021] The present invention also provides the application of high-temperature heat-insulating aerogel as a heat-insulating material for the battery core spacer.

[0022] The beneficial effects of the present invention are as follows: ① The high-temperature treatment process is applied to the hydrophobic fiber material substrate, and physical and chemical changes such as decomposition and volatilization of the organic matter inside the substrate are promoted by means of the high-temperature environment, thereby effectively reducing its organic matter content. The reduction of the organic matter content can reduce the heat conduction path generated by the organic matter, and then significantly improve the overall heat-insulating performance of the material, so that the diffusion of heat can be more effectively blocked during the heat transfer process.

[0023] ② The structure and composition of the ceramic aerogel are optimized by increasing the content of precursor silicon. The increase in silicon content helps to enhance the chemical bonding and the stability of the microstructure inside the ceramic aerogel, enabling it to better maintain the structural integrity when subjected to external stress, thereby effectively improving the strength of the ceramic aerogel to meet the requirements of the mechanical properties of the heat-insulating material under different working conditions.

[0024] ③ The metal hydroxide phase change material is added to the heat-insulating system. During the temperature change process, the phase change material undergoes a phase change, and a large amount of heat is absorbed or released during this process while its temperature remains relatively constant. When the working temperature of the battery increases, the phase change material absorbs heat and undergoes a phase change, thereby delaying the transfer of heat to the surrounding environment, further enhancing the heat-insulating effect of the entire heat-insulating structure, and improving the stability and reliability of the heat-insulating performance.

[0025] ④ A light-shielding agent such as titanium dioxide is added to the heat-insulating material. Under high-temperature conditions, the light-shielding agent can effectively reflect, scatter, and absorb radiant heat, reduce the propagation and transfer of thermal radiation inside the heat-insulating material, and reduce the heat accumulation and conduction caused by thermal radiation, thereby significantly improving the heat-insulating performance of the heat-insulating material under high-temperature working conditions and ensuring the effectiveness of the heat-insulating structure under high-temperature conditions.

[0026] ⑤After the combination and preparation of the above basic materials, the composition and microstructure of the aerogel are further optimized through aging, resulting in a final product with better high-temperature heat insulation performance and better mechanical strength. The ceramic aerogel has good heat insulation performance and high strength. The obtained product has a high-temperature heat insulation of over 144 °C per millimeter, meeting the high-temperature heat insulation requirements of the cell spacer heat insulation material. Detailed implementation mode

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the protection scope of the claims of the present invention.

[0028] It should be noted that the endpoints and any values within the ranges disclosed in this document are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, combinations can be made between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this document.

[0029] Unless otherwise defined, all terms, symbols, and other scientific terms used in this document are intended to have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. In some cases, terms with commonly understood meanings are defined herein for the purpose of clarification or easy reference. Such definitions herein should not be construed as indicating a significant difference from the conventional understanding in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted through conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments follows the protocols and parameters provided by the manufacturers.

[0030] The present invention mainly relates to a high-temperature heat-insulating aerogel, its preparation method, and application. The specific process of the preparation method includes the following steps:

[0031] Step 1: Heat the hydrophobic fiber material to 100 - 500 °C and keep it warm for 0.5 - 5 h to remove organic substances; the hydrophobic fiber material is selected from one or more of aluminosilicate ceramic fiber paper, glass fiber wet felt, and non-woven fabric; Step 2: Mix the solvent and the catalyst and heat up to 30 - 80°C. After adjusting the pH of the solution to 1 - 7, preferably to 2 - 5, add the silicon source, and hydrolyze at 40 - 80°C for 0.5 - 24 h. After cooling to room temperature, add the phase change material and the light-shielding agent and stir at high speed, then add the alkaline solution and stir evenly, and then pour it onto the pretreated hydrophobic fiber material substrate to form a composite wet gel; the silicon source is selected from one or more of tetraethyl orthosilicate, ethyl silicate, triethoxysilane, methyl silicate, trimethylethoxysilane, the solvent is selected from one or more of methanol, ethanol, ethyl acetate, propanol, ethylene glycol, the catalyst is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid solution, the phase change material is selected from one or more of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, the light-shielding agent is selected from one or more of titanium dioxide, zinc oxide, carbon black, kaolin, and the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonia water; Step 3: Mix the composite wet gel with the hydrophilic organic reagent in a volume ratio of 1:1 - 1:10, and age by water bath heating; the water-soluble organic reagent is selected from one or more of methanol, ethanol, ethyl acetate, propanol, ethylene glycol, the temperature of water bath heating for aging is 40 - 70°C, and the time is 0.5 - 12 h; Step 4: Carry out cleaning and drying treatment on the product obtained in Step 3 by supercritical carbon dioxide drying at a temperature of 30 - 70°C and a pressure of 5 - 16 MPa to obtain a high-temperature heat-insulating ceramic aerogel product.

[0032] The obtained high-temperature heat-insulating aerogel product can be used as a heat-insulating material for the battery core interval under high-pressure environments.

[0033] The following specific examples are used to illustrate the concept and effect of the present invention.

[0034] Example 1 The specific preparation steps are as follows: (1) The hydrophobic fiber material is selected as aluminosilicate ceramic fiber paper, which is heat-treated at 300°C for 3 hours to decompose and volatilize organic substances and reduce the organic substance content. The volume ratio of the aluminosilicate ceramic fiber paper to the sum of the volumes of the silicon source, solvent, catalyst, and alkaline solution is 1:1.2.

[0035] (2) By weight, mix 40 parts of tetraethyl orthosilicate (silicon source), 50 parts of ethanol (solvent), and 1 part of hydrochloric acid (catalyst), heat up to 60°C, adjust the pH to 2, and hydrolyze for 4 hours. After cooling to room temperature, add 10 parts of calcium hydroxide (phase change material) and 10 parts of carbon black (light-shielding agent), and stir at high speed for 20 minutes. Add 10 parts of ammonia water (alkaline solution) to adjust the pH to alkaline, stir evenly, and pour it onto the aluminosilicate ceramic fiber paper substrate obtained in step (1) to form a composite wet gel.

[0036] (3) Mix the composite wet gel with ethanol at a volume ratio of 1:5 and heat and age it in a water bath at 60°C for 12 hours.

[0037] (4) Use the supercritical drying method to clean and dry the aged product to obtain the improved sample - 1 of the final ceramic aerogel bare material.

[0038] (5) Cut the dried ceramic aerogel sample into a 100*100 sample, hot - press and apply a 0.02 - mm flame - retardant hot - pressed PET film, and seal the edges by 2 - 5 mm for performance testing.

[0039] Example 2 The specific preparation steps are as follows: (1) Select aluminosilicate ceramic fiber paper as the hydrophobic fiber material, and heat - treat it at 400°C for 3 hours to decompose and volatilize organic substances and reduce the organic substance content. The volume ratio of the aluminosilicate ceramic fiber paper to the sum of the volumes of the silicon source, solvent, catalyst, and alkaline solution is 1:1.2.

[0040] (2) By weight, mix 40 parts of tetraethyl orthosilicate (silicon source), 50 parts of ethanol (solvent), and 1 part of hydrochloric acid (catalyst), heat to 60°C, adjust the pH to 2, and hydrolyze for 5 hours. After cooling to room temperature, add 10 parts of calcium hydroxide (phase - change material) and 10 parts of carbon black (light - shielding agent), and stir at high speed for 20 minutes. Add 3 parts of sodium hydroxide (alkaline solution) to adjust the pH to alkaline, stir evenly, and pour it onto the aluminosilicate ceramic fiber paper substrate obtained in step (1) to form a composite wet gel.

[0041] (3) Mix the composite wet gel with ethanol at a volume ratio of 1:10 and heat and age it in a water bath at 60°C for 16 hours.

[0042] (4) Use the supercritical drying method to clean and dry the aged product to obtain the improved sample - 2 of the final ceramic aerogel bare material.

[0043] (5) Cut the dried ceramic aerogel sample into a 100*100 sample, hot - press and apply a 0.02 - mm flame - retardant hot - pressed PET film, and seal the edges by 2 - 5 mm for performance testing.

[0044] Example 3 The specific preparation steps are as follows: (1) Select aluminosilicate ceramic fiber paper as the hydrophobic fiber material, and heat - treat it at 500°C for 4 hours to decompose and volatilize organic substances and reduce the organic substance content. The volume ratio of the aluminosilicate ceramic fiber paper to the sum of the volumes of the silicon source, solvent, catalyst, and alkaline solution is 1:1.2.

[0045] (2) Mix 40 parts of tetraethyl orthosilicate (silicon source), 50 parts of ethanol (solvent), and 1 part of hydrochloric acid (catalyst) by weight, heat up to 60 °C, adjust the pH to 2, and hydrolyze for 6 hours. After cooling to room temperature, add 10 parts of calcium hydroxide (phase change material) and 10 parts of carbon black (light-shielding agent), and stir at high speed for 20 minutes. Add 3 parts of sodium hydroxide (alkaline solution) to adjust the pH to alkaline, stir evenly, and pour it onto the aluminosilicate ceramic fiber paper substrate obtained in step (1) to form a composite wet gel.

[0046] (3) Mix the composite wet gel and ethanol at a volume ratio of 1:10, and heat and age in a 60 °C water bath for 24 hours.

[0047] (4) Use the supercritical drying method to clean and dry the aged product to obtain the final improved sample of ceramic aerogel bare material - 3.

[0048] (5) Cut the dried ceramic aerogel sample into a 100*100 sample, hot-press and apply a 0.02 mm flame-retardant hot-pressed PET film, and seal the edges with 2 - 5 mm for performance testing.

[0049] Comparative Example 1 The specific preparation steps are as follows: (1) Mix 30 parts of tetraethyl orthosilicate (silicon source), 45 parts of ethanol (solvent), and 1 part of hydrochloric acid (catalyst) by weight, heat up to 60 °C, adjust the pH to 2, and hydrolyze for 3 hours. After cooling to room temperature, add 3 parts of sodium hydroxide (alkaline solution) to adjust the pH to alkaline, stir evenly, and pour it onto the aluminosilicate ceramic fiber paper substrate to form a composite wet gel.

[0050] (2) Mix the composite wet gel and ethanol at a volume ratio of 1:5, and heat and age in a 60 °C water bath for 6 hours.

[0051] (3) Use the supercritical drying method to clean and dry the aged product to obtain the final comparative sample of ceramic aerogel bare material - 1.

[0052] (4) Cut the dried ceramic aerogel sample into a 100*100 sample, hot-press and apply a 0.02 mm flame-retardant hot-pressed PET film, and seal the edges with 2 - 5 mm for performance testing.

[0053] Comparative Example 2 The specific preparation steps are as follows: (1) Mix 35 parts of tetraethyl orthosilicate (silicon source), 50 parts of ethanol (solvent), and 1 part of hydrochloric acid (catalyst) by weight, heat up to 60 °C, adjust the pH to 2, and hydrolyze for 4 hours. After cooling to room temperature, add 3 parts of sodium hydroxide (alkaline solution) to adjust the pH to alkaline, stir evenly, and pour it onto the aluminosilicate ceramic fiber paper substrate to form a composite wet gel.

[0054] (2) The composite wet gel was mixed with ethanol in a volume ratio of 1:5 and heated in a 60°C water bath for 8 hours.

[0055] (3) The aged product is cleaned and dried by supercritical drying to obtain the final ceramic aerogel bare material comparison sample-2.

[0056] (4) The dried ceramic aerogel samples were cut into 100*100 samples, hot-pressed with 0.02mm flame-retardant hot-pressed PET film, and sealed with 2-5mm edges for performance testing.

[0057] Comparative Example 3 The specific preparation steps are as follows: (1) By weight, 40 parts of ethyl orthosilicate (silicon source), 50 parts of ethanol (solvent) and 1 part of hydrochloric acid (catalyst) were mixed, heated to 60°C, adjusted to pH 2, and hydrolyzed for 4 hours. After cooling to room temperature, 3 parts of sodium hydroxide (alkaline solution) were added to adjust the pH to alkaline, stirred evenly, and poured onto the aluminum silicate ceramic fiber paper substrate to form a composite wet gel.

[0058] (2) The composite wet gel was mixed with ethanol in a volume ratio of 1:5 and heated in a 60°C water bath for 12 hours.

[0059] (3) The aged product is cleaned and dried by supercritical drying to obtain the final ceramic aerogel bare material comparison sample-3.

[0060] (4) The dried ceramic aerogel samples were cut into 100*100 samples, hot-pressed with 0.02mm flame-retardant hot-pressed PET film, and sealed with 2-5mm edges for performance testing.

[0061] Performance test method: ① Measure and record the sample thickness. Place two 1.0mm aluminum plates (one with slots and one without slots) on the cold side of the sample. Place the cold side thermocouple at the slotted part of the aluminum plate. Place a 1.0mm aluminum plate (without slots) on the hot side of the sample and fix them with PI tape. ② Set the heating table temperature to 550℃, place a 12mm aluminum plate (aluminum plate size 110×110×12mm) on the heating table, and start heating; the thermocouple inside the 12mm aluminum plate is controlled at 470±5℃; ③ Sequentially stick two 18mm calcium silicate boards and the sample to the pressure table above the heating table with PI tape; ④After the thermocouple in the 12mm aluminum plate is controlled at 470±5℃, start recording the thermocouple temperature rise curve; ⑤ Apply 0.7MPa pressure and cool down naturally after 2 minutes; start timing after pressurization and record the hot surface @ cold surface temperature data for 15 minutes; ⑥ Evaluate the maximum temperature of the cold surface and the temperature difference between the hot and cold surfaces corresponding to the maximum temperature of the cold surface; The test results of the samples of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below: As can be seen from Table 1, the ceramic aerogel sample prepared by the method of the present invention has a temperature difference of more than 144° C. between the hot and cold surfaces under high pressure, which meets the requirements for use of thermal insulation materials for battery cells under high pressure environments.

[0062] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

[0063] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A high temperature thermal insulation aerogel, characterized in that: The invention comprises a hydrophobic fiber material and substances in the following weight proportions: 20-40 parts of a silicon source, 40-50 parts of a solvent, 1-5 parts of a catalyst, 1-10 parts of a phase change material, 1-10 parts of a sunscreen, and 5-10 parts of an alkaline solution; wherein the ratio of the volume of the hydrophobic fiber material to the sum of the volumes of the silicon source, the solvent, the catalyst, and the alkaline solution is 1:(1.1-1.5).

2. A high temperature thermal insulation aerogel according to claim 1, characterized in that: The hydrophobic fiber material is selected from one or more of aluminum silicate ceramic fiber paper, glass fiber wet-laid mat, and non-woven fabric; And / or, the silicon source is selected from one or more of tetraethyl orthosilicate, ethyl silicate, triethoxysilane, methyl silicate, and trimethylethoxysilane; And / or, the solvent is selected from one or more of methanol, ethanol, ethyl ester, propanol, and ethylene glycol; And / or, the catalyst is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid solution; And / or, the phase change material is selected from one or more of aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; And / or, the sunscreen is selected from one or more of titanium dioxide, zinc oxide, carbon black, and kaolin; And / or, the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water.

3. A method for preparing the high temperature thermal insulation aerogel according to claim 1 or 2, characterized in that: The steps include: Step 1: pre-treating the hydrophobic fiber material at high temperature to remove organic matter; Step 2: Mix and hydrolyze the silicon source, solvent and catalyst, then add phase change material, sunscreen and alkaline solution to the hydrolyzate, stir evenly and pour on the product obtained in step 1 to form a composite wet gel; Step 3, mixing the composite wet gel and the hydrophilic organic reagent in a volume ratio of 1:1-1:10, and heating and aging in a water bath; Step 4: Clean and dry the product obtained in step 3 to obtain high-temperature thermal insulation ceramic aerogel.

4. The method for preparing a high temperature thermal insulation aerogel according to claim 3, characterized in that: In the step 1, the high temperature treatment is to heat the hydrophobic fiber material to 100-500° C. and keep the temperature for 0.5-5 hours.

5. The method for preparing a high temperature thermal insulation aerogel according to claim 3, characterized in that: The specific operation of the step 2 is to mix the solvent and the catalyst and heat it to 30-80°C, add the silicon source after the pH of the solution reaches 1-7, hydrolyze at 40-80°C for 0.5-24h, add the phase change material and the sunscreen after cooling to room temperature and stir at high speed, then add the alkaline solution and stir evenly, and then pour it on the pretreated hydrophobic fiber paper material to form a composite wet gel.

6. The method for preparing a high temperature thermal insulation aerogel according to claim 5, characterized in that: The solvent and catalyst are mixed and heated to 30-80°C, and the silicon source is added after the pH of the solution reaches 2-5.

7. The method for preparing a high temperature thermal insulation aerogel according to claim 3, characterized in that: The hydrophilic organic reagent in step 3 is selected from one or more of methanol, ethanol, ethyl ester, propanol, and ethylene glycol; And / or, the temperature of water bath heating aging in step 3 is 40-70° C. and the time is 0.5-12 h.

8. The method for preparing a high temperature thermal insulation aerogel according to claim 3, characterized in that: In step 4, cleaning and drying are performed by supercritical drying.

9. The method for preparing a high temperature thermal insulation aerogel according to claim 8, characterized in that: The cleaning and drying are carried out by supercritical drying method, which is carbon dioxide supercritical drying, with a temperature of 30-70° C. and a pressure of 5-16 MPa.

10. Use of the high temperature thermal insulation aerogel as claimed in claim 1 or 2 as thermal insulation material for battery cells.

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