A preparation method of heat dissipation aerogel for lithium battery

Abstract

The present invention belongs to the field of aerogel technology, and in particular to a method for preparing a heat dissipation aerogel for lithium batteries, comprising adding copper salt to deionized water, then adding cross-linked carboxylated cellulose, stirring for adsorption, then adding sodium borohydride and water, stirring for a reduction reaction, and finally pre-freezing and freeze-drying to obtain a heat dissipation aerogel; the nano-copper particles of the present invention have good dispersibility in the aerogel, are not easy to agglomerate, form a heat conduction path in the aerogel, significantly improve the thermal conductivity of the aerogel, and show better heat conduction and heat dissipation performance. After dialdehyde cellulose is cross-linked with 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, a rigid terphenylbenzene structure is introduced into the skeleton of the aerogel, significantly improving the strength and modulus of the cellulose aerogel, showing higher compressive stress, compression modulus and mechanical properties. It can be used as a heat-conducting and heat-dissipating material and a protective layer, and has broad application prospects in lithium batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of aerogels, and in particular relates to a method for preparing heat dissipation aerogel for lithium batteries. Background Art

[0002] Cellulose is the world's most abundant polysaccharide polymer compound. It is inexpensive, readily available, and pollution-free. The development and utilization of cellulose is a research trend. Cellulose can be processed through chemical cross-linking, freeze-drying, and other processes to produce aerogel materials, which are widely used in adsorption materials, phase change materials, thermal insulation materials, and other fields. Cellulose aerogel can be made into materials such as carbon aerogel for lithium battery electrodes and aerogel membranes for battery separators, and has broad development prospects in lithium batteries. However, traditional cellulose aerogels have very low thermal conductivity, resulting in poor thermal conductivity and heat dissipation performance, as well as poor mechanical strength, which greatly limits their practical application.

[0003] Lithium batteries offer advantages such as high energy density, excellent cycle performance, no memory effect, and environmental friendliness. Furthermore, with the advancement of science and technology, lithium batteries have become the mainstream battery for new energy vehicles and electronic devices. However, during actual use, lithium batteries generate significant heat, and components such as the battery casing suffer from poor thermal conductivity and heat dissipation, severely impacting their performance. This invention aims to prepare a heat-dissipating aerogel material with high thermal conductivity and strength, expanding the practical application of cellulose aerogel in components such as lithium battery casings. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a heat dissipation aerogel with high thermal conductivity and high strength for use with lithium batteries.

[0005] The technical solution provided by the present invention is: a method for preparing heat dissipation aerogel is:

[0006] (1) Add N,N-dimethylformamide and dialdehyde cellulose to the reaction vessel, stir and mix, then add 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene (structural formula: ), after stirring the reaction, the reaction vessel is placed in an ice water bath to precipitate the precipitate, which is filtered, washed with ethanol, and dried to cross-link the carboxylated cellulose.

[0007] (2) Add copper salt to deionized water, stir to dissolve, then add cross-linked carboxylated cellulose, ultrasonically disperse in an ultrasonic instrument, and then stir and adsorb at 20-40°C for 6-18 hours, then add sodium borohydride and water, stir at 20-30°C for reduction reaction for 24-36 hours, filter, wash with deionized water, then add to deionized water, ultrasonically disperse, and finally pre-freeze at -25°C to -35°C for 6-10 hours, and then freeze-dry in a freeze dryer at -50°C to -60°C for 36-48 hours to obtain heat dissipation aerogel.

[0008] Furthermore, the mass of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene is 50-180% of the mass of dialdehyde cellulose.

[0009] Furthermore, the reaction in (1) is carried out at 45-60°C for 18-36 hours.

[0010] Furthermore, the mass of the copper salt is 80-300% of the mass of the cross-linked carboxylated cellulose.

[0011] Furthermore, the copper salt is copper chloride, copper sulfate or copper nitrate.

[0012] Furthermore, the preparation method of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene is as follows: N,N-dimethylformamide, 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene in a ratio of 1 mol:(3-3.3) mol:(0.08-0.1) mol:(9-10.8) mol, 3-amino-5-bromobenzoic acid, palladium acetate, sodium carbonate are added to a reaction vessel equipped with a condenser reflux tube, and deionized water is added, nitrogen is introduced, and the mixture is heated to 85-100 ° C. and stirred for 5-10 hours. Deionized water is added and the reaction vessel is placed in an ice-water bath to precipitate the precipitate, which is filtered, washed with deionized water, and then recrystallized from ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene. The reaction formula is:

[0013]

[0014] Furthermore, the application of heat dissipation aerogel in lithium batteries.

[0015] The technical effect of the present invention is that the present invention utilizes 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene containing multiple amino groups to undergo Schiff base condensation reaction with the aldehyde group of dialdehyde cellulose to achieve cross-linking of dialdehyde cellulose to obtain cross-linked carboxylated cellulose containing carboxyl groups, and then the introduced carboxyl groups react with Cu2+ and CuCl2+ to form copper salts such as copper chloride. 2+ It has a strong coordination chelation effect and can 2+ Uniformly adsorbed into the skeleton and pores of cross-linked cellulose, and then reduced by sodium borohydride, Cu2+ Nano-copper particles are generated and evenly distributed within a cross-linked cellulose matrix. Finally, freeze-dried, heat-dissipating aerogel is obtained. The nano-copper particles disperse well within the aerogel and resist agglomeration. They form thermal pathways within the aerogel, significantly increasing its thermal conductivity and demonstrating improved heat conduction and heat dissipation performance. This can be applied to components such as lithium battery casings to achieve heat dissipation.

[0016] The dialdehyde cellulose of the present invention is cross-linked with 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene to introduce a rigid terphenylbenzene structure into the aerogel's skeleton, significantly improving the strength and modulus of the cellulose aerogel. Furthermore, the nano-copper particles themselves possess high mechanical strength and, when embedded in the aerogel matrix, support the skeleton, resulting in the aerogel exhibiting higher compressive stress, compression modulus, and mechanical properties. The material can be applied to components such as lithium battery casings to absorb and buffer stress, serving as a protective layer to protect lithium battery components. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0018] The CAS number of the 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene of the present invention is 900795-73-5.

[0019] The CAS number of 3-amino-5-bromobenzoic acid is 42237-85-4.

[0020] The CAS number of 1,3,5-tris(4-aminophenyl)benzene is 118727-34-7.

[0021] Microcrystalline cellulose brand: Yuanye S14009.

[0022] Preparation of dialdehyde cellulose: Soak 10g of microcrystalline cellulose in a 15% sodium hydroxide solution for 24 hours, filter, wash with deionized water, and dry to obtain alkali-treated microcrystalline cellulose. Add 300mL of deionized water and 12g of sodium periodate to a reaction flask, add sulfuric acid dropwise to adjust the pH to 2, add 10g of microcrystalline cellulose, stir and mix, and react at 35°C for 2 hours. Add 800mL of ethylene glycol to remove unreacted sodium periodate, filter, wash with deionized water, and dry to obtain dialdehyde cellulose.

[0023] Example 1

[0024] (1) Add 800 mL of N,N-dimethylformamide and 50 mmol of 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene into a reaction vessel equipped with a condenser reflux tube. ), 165 mmol 3-amino-5-bromobenzoic acid, 5 mmol palladium acetate, 450 mmol sodium carbonate, and add 100 mL of deionized water, introduce nitrogen, heat to 100 ° C, stir and react for 5 hours, add deionized water, place the reaction vessel in an ice water bath to precipitate the precipitate, filter and wash with deionized water, and then recrystallize from ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene.

[0025] (2) Add 500 mL of N,N-dimethylformamide and 20 g of dialdehyde cellulose to a reaction vessel, stir and mix, then add 20 g of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, stir and react at 45°C for 36 hours, place the reaction vessel in an ice water bath, precipitate, filter, wash with ethanol, and dry to cross-link the carboxylated cellulose.

[0026] (3) Add 2.4 g of copper chloride to 100 mL of deionized water and stir to dissolve. Then add 3 g of cross-linked carboxylated cellulose and disperse it by ultrasonication in an ultrasonic instrument. Then stir and adsorb it at 20 ° C for 18 h. Then add 52 g of sodium borohydride and 300 mL of water and stir and reduce it at 25 ° C for 24 h. Filter and wash with deionized water. Then add it to 200 mL of deionized water and disperse it by ultrasonication. Finally, pre-freeze it at -25 ° C for 10 h, and then freeze-dry it in a freeze dryer at -50 ° C for 48 h to obtain heat dissipation aerogel.

[0027] Example 2

[0028] (1) To a reaction vessel equipped with a condenser reflux tube, 600 mL of N,N-dimethylformamide, 50 mmol of 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene, 150 mmol of 3-amino-5-bromobenzoic acid, 4.4 mmol of palladium acetate, and 540 mmol of sodium carbonate were added, and 120 mL of deionized water was added. Nitrogen was introduced, and the mixture was heated to 85°C and stirred for 10 hours. Deionized water was added, and the reaction vessel was placed in an ice-water bath to precipitate the precipitate. After filtering, the precipitate was washed with deionized water and then recrystallized from ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene.

[0029] (2) Add 500 mL of N,N-dimethylformamide and 20 g of dialdehyde cellulose to a reaction vessel, stir and mix, then add 25 g of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, stir and react at 50°C for 24 hours, place the reaction vessel in an ice water bath, precipitate, filter, wash with ethanol, and dry to cross-link the carboxylated cellulose.

[0030] (3) Add 4.5 g of copper sulfate to 100 mL of deionized water and stir to dissolve. Then add 3 g of cross-linked carboxylated cellulose and disperse it by ultrasonication in an ultrasonic instrument. Then stir and adsorb it at 30 ° C for 12 h. Then add 80 g of sodium borohydride and 500 mL of water and stir and reduce it at 20 ° C for 6 h. Filter and wash with deionized water. Then add it to 200 mL of deionized water and disperse it by ultrasonication. Finally, pre-freeze it at -35 ° C for 6 h and then freeze-dry it in a freeze dryer at -60 ° C for 36 h to obtain heat dissipation aerogel.

[0031] Example 3

[0032] (1) To a reaction vessel equipped with a condenser reflux tube, 800 mL of N,N-dimethylformamide, 50 mmol of 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene, 165 mmol of 3-amino-5-bromobenzoic acid, 5 mmol of palladium acetate, and 520 mmol of sodium carbonate were added, and 120 mL of deionized water was added. Nitrogen was introduced, and the mixture was heated to 85°C and stirred for 10 hours. Deionized water was added, and the reaction vessel was placed in an ice-water bath to precipitate the precipitate. The precipitate was filtered, washed with deionized water, and then recrystallized from ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene.

[0033] (2) Add 800 mL of N,N-dimethylformamide and 20 g of dialdehyde cellulose to a reaction vessel, stir and mix, then add 30 g of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, stir and react at 60°C for 18 hours, place the reaction vessel in an ice water bath, precipitate, filter, wash with ethanol, and dry to cross-link the carboxylated cellulose.

[0034] (3) 7 g of copper sulfate was added to 120 mL of deionized water and stirred to dissolve. Then, 3 g of cross-linked carboxylated cellulose was added and dispersed by ultrasonication in an ultrasonic instrument. Then, the mixture was stirred and adsorbed at 40 ° C for 6 h. Then, 120 g of sodium borohydride and 800 mL of water were added and stirred at 20 ° C for reduction reaction for 36 h. The mixture was filtered and washed with deionized water. Then, the mixture was added to 200 mL of deionized water and dispersed by ultrasonication. Finally, the mixture was pre-frozen at -25 ° C for 10 h and then freeze-dried in a freeze dryer at -60 ° C for 36 h to obtain heat dissipation aerogel.

[0035] Example 4

[0036] (1) To a reaction vessel equipped with a condenser reflux tube, 700 mL of N,N-dimethylformamide, 50 mmol of 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene, 160 mmol of 3-amino-5-bromobenzoic acid, 4 mmol of palladium acetate, and 450 mmol of sodium carbonate were added, and 100 mL of deionized water was added. Nitrogen was introduced, and the mixture was heated to 90° C. and stirred for 8 h. Deionized water was added, and the reaction vessel was placed in an ice-water bath to precipitate the precipitate. The precipitate was filtered, washed with deionized water, and then recrystallized from ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene.

[0037] (2) Add 800 mL of N,N-dimethylformamide and 20 g of dialdehyde cellulose to a reaction vessel, stir and mix, then add 36 g of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, stir and react at 45°C for 36 hours, place the reaction vessel in an ice-water bath, precipitate, filter, wash with ethanol, and dry to cross-link the carboxylated cellulose.

[0038] (3) 9 g of copper nitrate was added to 150 mL of deionized water and stirred to dissolve. Then, 3 g of cross-linked carboxylated cellulose was added and dispersed by ultrasonication in an ultrasonic instrument. Then, 140 g of sodium borohydride and 1 L of water were added and stirred at 30 ° C for 12 h for reduction reaction. Then, the mixture was filtered and washed with deionized water. Then, the mixture was added to 200 mL of deionized water and dispersed by ultrasonication. Finally, the mixture was pre-cooled at -30 ° C for 8 h and then freeze-dried in a freeze dryer at -50 ° C for 48 h to obtain heat dissipation aerogel.

[0039] Comparative Example 1

[0040] (3) 3 g of dialdehyde cellulose was added to 200 mL of deionized water and dispersed by ultrasound. Finally, it was pre-frozen at -25 °C for 10 h and then freeze-dried in a freeze dryer at -50 °C for 48 h to obtain heat dissipation aerogel.

[0041] Comparative Example 2

[0042] (1) To a reaction vessel equipped with a condenser reflux tube, 800 mL of N,N-dimethylformamide, 50 mmol of 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene, 165 mmol of 3-amino-5-bromobenzoic acid, 5 mmol of palladium acetate, and 450 mmol of sodium carbonate were added, and 100 mL of deionized water was added. Nitrogen was introduced, and the mixture was heated to 100° C. and stirred for 5 h. Deionized water was added, and the reaction vessel was placed in an ice-water bath to precipitate the precipitate. The precipitate was filtered, washed with deionized water, and then recrystallized from ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene.

[0043] (2) Add 500 mL of N,N-dimethylformamide and 20 g of dialdehyde cellulose to a reaction vessel, stir and mix, then add 20 g of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, stir and react at 45°C for 36 hours, place the reaction vessel in an ice water bath, precipitate, filter, wash with ethanol, and dry to cross-link the carboxylated cellulose.

[0044] (3) 3 g of cross-linked carboxylated cellulose was added to 200 mL of deionized water and dispersed by ultrasound. Finally, the mixture was pre-frozen at -25 °C for 10 h and then freeze-dried in a freeze dryer at -50 °C for 48 h to obtain heat dissipation aerogel.

[0045] Comparative Example 3

[0046] 2.4 g of copper chloride was added to 100 mL of deionized water and stirred to dissolve. Then 3 g of dialdehyde cellulose was added and ultrasonically dispersed in an ultrasonic instrument. Then, the mixture was stirred and adsorbed at 20°C for 18 hours. Then, 52 g of sodium borohydride and 300 mL of water were added and stirred at 25°C for a reduction reaction for 24 hours. The mixture was filtered, washed with deionized water, and then added to 200 mL of deionized water and ultrasonically dispersed. Finally, the mixture was pre-frozen at -25°C for 10 hours and then freeze-dried in a freeze dryer at -50°C for 48 hours to obtain a heat dissipating aerogel.

[0047] Comparative Example 4

[0048] (1) Add 500 mL of N,N-dimethylformamide and 20 g of dialdehyde cellulose to a reaction vessel, stir and mix, then add 20 g of 1,3,5-tris(4-aminophenyl)benzene, stir and react at 45°C for 36 hours, place the reaction vessel in an ice-water bath, precipitate, filter, wash with ethanol, and dry to cross-link the cellulose.

[0049] (2) Add 2.4 g of copper chloride to 100 mL of deionized water and stir to dissolve. Then add 3 g of cross-linked cellulose and disperse it by ultrasonication in an ultrasonic instrument. Then stir and adsorb it at 20 ° C for 18 h. Then add 52 g of sodium borohydride and 300 mL of water and stir and reduce it at 25 ° C for 24 h. Filter and wash with deionized water. Then add it to 200 mL of deionized water and disperse it by ultrasonication. Finally, pre-freeze it at -25 ° C for 10 h, and then freeze-dry it in a freeze dryer at -50 ° C for 48 h to obtain heat dissipation aerogel.

[0050] With reference to ISO 22007-2:2008, Part 2: Instantaneous Plane Heat Source (Heating Plate) Method, a thermal conductivity tester was used to test the thermal conductivity of the heat dissipating aerogel. The aerogel specification was 30 cm × 30 cm × 10 cm.

[0051] The compression performance of the heat dissipation aerogel was tested using a microcomputer-controlled electronic universal testing machine at a compression speed of 5 mm / min and a compression height of 70% of the original height. Five groups of samples were tested and the average value was taken.

[0052] The test results are shown in Table 1.

[0053] Table 1 Thermal conductivity and compression properties of heat dissipation aerogels

[0054]

[0055]

[0056] After testing, Comparative Example 1 uses dialdehyde cellulose as the aerogel matrix, and its compressive stress (strain 70%) is 8.8 kPa, the compression modulus is 82.4 kPa, and the thermal conductivity is 0.039 W·m -1 ·k -1 , poor compression performance, poor thermal conductivity and heat dissipation performance.

[0057] In Examples 1 to 4, 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene containing multiple amino groups was used to undergo Schiff base condensation reaction with the aldehyde groups of dialdehyde cellulose to achieve cross-linking of dialdehyde cellulose to obtain cross-linked carboxylated cellulose containing carboxyl groups. The introduced carboxyl groups then reacted with copper salts such as copper chloride to form Cu 2+ It has a strong coordination chelation effect and can 2+ Uniformly adsorbed into the skeleton and pores of cross-linked cellulose, and then reduced by sodium borohydride, Cu 2+ Nano copper particles are generated and evenly distributed in the skeleton of cross-linked cellulose, and finally freeze-dried to obtain heat dissipation aerogel. Nano copper particles are well dispersed in the aerogel and are not easy to agglomerate. They form heat conduction paths in the aerogel, significantly improving the thermal conductivity of the aerogel and showing better thermal conductivity and heat dissipation performance. In addition, after the dialdehyde cellulose is cross-linked with 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, a rigid terphenylbenzene structure ( ), significantly improving the strength and modulus of cellulose aerogel. At the same time, the nano-copper particles themselves have high mechanical strength and are embedded in the aerogel matrix, which can play the role of supporting the skeleton, making the aerogel exhibit higher compressive stress, compression modulus and mechanical properties.

[0058] Compared with Example 1, Comparative Example 2 did not add copper salt, and the aerogel did not contain copper nanoparticles. The thermal conductivity was very low, and the thermal and heat dissipation performance was very poor. The compressive stress and modulus were also lower than those of Example 1. However, the aerogel of Comparative Example 2 contained a rigid terphenylbenzene structure, and the compressive stress and modulus were significantly higher than those of Comparative Example 1.

[0059] The dialdehyde cellulose of Comparative Example 3 does not contain carboxyl groups. 2+ The coordination chelation and adsorption performance of Cu 2+ The Cu2+ is not evenly adsorbed into the skeleton and pores of the cross-linked cellulose, resulting in the formation of 2+ The generated nano-copper particles are not evenly distributed in the cross-linked cellulose skeleton. The nano-copper particles are poorly dispersed in the aerogel and easily agglomerated, and no good heat conduction path is formed, resulting in a thermal conductivity significantly lower than that of Example 1.

[0060] Comparative Example 4: 1,3,5-tris(4-aminophenyl)benzene was used as a crosslinking agent to react with dialdehyde cellulose. The obtained cellulose aerogel also contained a rigid triphenylbenzene structure, and the compressive stress and compression modulus were significantly improved. However, the crosslinked cellulose did not contain carboxyl groups, and the Cu 2+ The coordination chelation and adsorption performance of the nano-copper particles are poor, resulting in poor dispersion of the generated nano-copper particles in the aerogel, easy agglomeration, and no good heat conduction path is formed. The thermal conductivity is significantly lower than that of Example 1, and the compression performance is also lower than that of Example 1.

[0061] The above embodiments are intended to illustrate the present invention only and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be encompassed by the scope of the claims of the present invention.

Claims

1. A method for preparing a heat dissipation aerogel, characterized in that: The preparation method is: (1) Add N,N-dimethylformamide and dialdehyde cellulose to a reaction vessel, stir and mix, then add 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene, stir and react, then place the reaction vessel in an ice water bath to precipitate, filter, wash with ethanol, and dry to cross-link the carboxylated cellulose; (2) Add copper salt to deionized water, stir to dissolve, then add cross-linked carboxylated cellulose, ultrasonically disperse in an ultrasonic instrument, then stir to adsorb, then add sodium borohydride and water, stir to carry out reduction reaction, filter, wash with deionized water, then add to deionized water, ultrasonically disperse, and finally pre-freeze and freeze-dry to obtain heat dissipation aerogel.

2. The method for preparing the heat dissipation aerogel according to claim 1, wherein: The mass of the 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene is 50-180% of the mass of the dialdehyde cellulose.

3. The method for preparing the heat dissipation aerogel according to claim 1, wherein: The reaction in (1) is carried out at 45-60°C for 18-36 hours.

4. The method for preparing the heat dissipation aerogel according to claim 1, wherein: The mass of the copper salt is 80-300% of the mass of the cross-linked carboxylated cellulose.

5. The method for preparing the heat dissipation aerogel according to claim 1, wherein: The copper salt is copper chloride, copper sulfate or copper nitrate.

6. The method for preparing heat dissipation aerogel according to claim 1, characterized in that: The stirring adsorption in (2) is carried out at 20-40°C for 6-18 hours.

7. The method for preparing heat dissipation aerogel according to claim 1, characterized in that: The reduction reaction in (2) is carried out at 20-30°C for 24-36 hours.

8. The method for preparing heat dissipation aerogel according to claim 1, characterized in that: The pre-freezing in (2) is carried out at -25°C to -35°C for 6-10 hours; and freeze drying is carried out at -50°C to -60°C for 36-48 hours.

9. The method for preparing heat dissipation aerogel according to claim 1, characterized in that: The preparation method of 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene comprises: adding N,N-dimethylformamide, 1,3,5-tris[4-(dihydroxyboryl)phenyl]benzene in a ratio of 1 mol:(3-3.3) mol:(0.08-0.1) mol:(9-10.8) mol, 3-amino-5-bromobenzoic acid, palladium acetate, and sodium carbonate to a reaction vessel equipped with a condenser reflux tube, adding deionized water, introducing nitrogen, heating to 85-100° C., stirring and reacting for 5-10 hours, adding deionized water, placing the reaction vessel in an ice-water bath to precipitate a precipitate, filtering, washing with deionized water, and then recrystallizing with ethanol to obtain 1,3,5-tris[4-(3-aminobenzoic acid)phenyl]benzene.

10. Use of the heat dissipation aerogel obtained by the preparation method according to any one of claims 1 to 9 in a lithium battery.

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