Aerogel fiber paper and preparation method therefor

Abstract

Aerogel fiber paper and a preparation method therefor. The preparation method comprises the following steps: S1, mixing deionized water, a fiber dispersing agent and modified fibers until uniform, so as to obtain a slurry A; S2, mixing deionized water, a titanium-dioxide-based composite aerogel powder, a powder surfactant and a dilute acid until uniform, so as to obtain a paste B; S3, combining the slurry A with the paste B by means of different forming methods, so as to obtain a pre-product; S4, spraying or coating the paste B onto a fiber matrix, and sequentially and alternately laying fiber matrix layers on the surface of the paste B, so as to obtain a stacked body M; and S5, mixing the pre-product or the stacked body with a binder, subjecting same to vacuum filtration and drying, and then performing programmed heating, cooling, cutting and packaging, so as to obtain aerogel fiber paper. The resulting aerogel fiber paper has a thickness of 0.5-5 mm, a room-temperature thermal conductivity of less than or equal to 0.017 W / (m·K), a high-temperature thermal conductivity of less than or equal to 0.033 W / (m·K), a tensile strength of greater than or equal to 0.75 MPa, and a forming rate of 100%.

Description

Aerogel fiber paper and preparation method thereof Technical Field

[0001] The present invention relates to the field of new energy battery thermal insulation, and in particular to aerogel fiber paper and a preparation method thereof. Background Art

[0002] The new energy vehicle industry has experienced rapid growth in recent years. As a core component of new energy vehicles, power batteries significantly impact their performance, safety, and lifespan. Lithium-ion batteries, due to their high energy density, long charge-discharge cycle life, wide operating temperature range, and lack of memory effect, currently hold the largest market share in the new energy vehicle industry. However, under abnormal conditions such as overheating and overcharging, lithium-ion batteries can experience thermal runaway, generating large amounts of heat in a short period of time, which can easily lead to combustion and explosion. Thermal protection technology is primarily used to address the propagation of thermal runaway in battery packs. This involves adding an insulation layer within the battery pack to prevent the spread of thermal runaway from the uncontrolled cell to surrounding cells, minimizing damage to the battery pack and any associated destructive effects.

[0003] Aerogel is a three-dimensional nanoporous structure composed of interconnected nanoparticles. It has excellent properties such as low density, large specific surface area, high porosity, low thermal conductivity, and low dielectric constant. Aerogel insulation materials combine high flame retardancy with lightweight design and low usage. Their performance surpasses that of traditional power battery insulation materials, making them the optimal choice for power battery cell insulation. However, existing aerogels have poor high-temperature stability, with temperatures exceeding 650°C for extended periods of use. However, the intense combustion stage of thermal runaway in lithium-ion batteries can reach temperatures of 877°C, with peak temperatures exceeding 1200°C. Therefore, aerogel insulation materials with more stable high-temperature insulation properties and higher heat resistance are needed.

[0004] Summary of the Invention

[0005] The object of the present invention is to solve the above-mentioned problems in the prior art and provide an aerogel fiber paper and a preparation method thereof. The obtained aerogel fiber paper has a thickness of 0.5 to 5 mm, a room temperature thermal conductivity of 25°C ≤ 0.017 W / (m·K), a high temperature thermal conductivity of 300°C ≤ 0.033 W / (m·K), a tensile strength ≥ 0.75 MPa, and a forming rate of 100%.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An aerogel fiber paper, the raw materials of which include, by weight, 800-1100 parts of deionized water, 0.05-0.15 parts of a fiber dispersant, 50-150 parts of modified fiber, 0.3-5 parts of a powder surfactant, 0.1-90 parts of a titanium dioxide-based composite aerogel powder, 0.1-10 parts of a binder, and 3-10 parts of a dilute acid;

[0008] The modified fiber is prepared by etching the fiber using a plasma generator to obtain the modified fiber;

[0009] The fiber is one or more of ceramic fiber, glass fiber, and organic fiber;

[0010] The organic fiber is one or more of ultra-high molecular weight polyethylene fiber, polypropylene fiber, polyamide fiber, polyetherimide fiber, polyacrylonitrile fiber, PET fiber, cotton fiber, hemp fiber, soybean fiber, and bamboo fiber;

[0011] The titanium dioxide-based composite aerogel powder is prepared by adding unmodified aerogel powder and n-butyl titanate into a solvent, uniformly dispersing the mixture, adding a particle size regulator, reacting the mixture at 50 to 80° C. for 2 to 8 hours under acidic conditions of pH 1 to 3, and centrifuging the mixture after the reaction and drying it to obtain the titanium dioxide-based composite aerogel powder.

[0012] The present invention uses DBD plasma to treat fibers to obtain modified fibers with hydroxyl groups on the surface. The hydroxyl groups on the surface of unmodified aerogel powder and the hydroxyl groups on the surface of n-butyl titanate are dehydrated to generate titanium dioxide-based composite aerogel powder. The titanium dioxide generated here is nano-scale, and the titanium dioxide-based composite aerogel powder still has hydroxyl groups on its surface, which can further react with the hydroxyl groups on the surface of the modified fiber.

[0013] The unmodified aerogel powder is one or more of SiO2 aerogel powder, Al2O3 aerogel powder, ZrO2 aerogel powder, SiC aerogel powder, SiO2-Al2O3 composite aerogel powder, SiO2-ZrO2 composite aerogel powder, and SiO2-Al2O3-ZrO2 composite aerogel powder;

[0014] The particle size of the unmodified aerogel powder is 5 to 500 μm;

[0015] The solvent is one or both of deionized water and anhydrous ethanol;

[0016] The diameter of the ceramic fiber in the fibers is 2-10 μm, the diameter of the glass fiber is 1-8 μm, and the diameter of the organic fiber is 5-15 μm.

[0017] The mass ratio of the unmodified aerogel powder, n-butyl titanate and particle size control agent is (0.2-3):(3-8):(0.01-1).

[0018] The particle size control agent is one or more of polydiacetylene, polyethylene glycol alkyl aryl ether sulfonate, N,N-dimethylformamide, and 2,5-dihydroxyterephthalic acid;

[0019] The fiber dispersant is one or both of polyacrylamide and sodium lauryl sulfate; the powder surfactant is one or both of KH550 and PVA.

[0020] The dilute acid is an aqueous solution of an acid, and the acid includes one of hydrochloric acid, nitric acid, and sulfuric acid, with a concentration of 0.1 to 5 mol / L.

[0021] A method for preparing aerogel fiber paper comprises the following steps:

[0022] S1. Stir deionized water and fiber dispersant evenly, add modified fiber in proportion, stir and disperse, and mix evenly to obtain slurry A;

[0023] S2. Deionized water, titanium dioxide-based composite aerogel powder, and powder surfactant are mechanically stirred at high speed at room temperature to mix uniformly, and dilute acid is added in batches to adjust the pH to 2-3 to obtain paste B;

[0024] S3, after mixing and stirring the slurry A described in S1 and the paste B described in S2 until uniformly dispersed, the mixed slurry is made into paper or molded to obtain a pre-product C1; alternatively, the slurry A described in S1 is directly made into paper or molded to obtain a pre-product C2;

[0025] S4, spraying or coating the paste B described in S2 uniformly on the fiber matrix, and then alternately stacking a single layer or multiple layers of fiber matrix on the surface of the paste B to obtain a laminate M having a multi-layer "sandwich biscuit" structure with alternating fiber matrix-slurry-fiber matrix, wherein the number of fiber matrix layers N1 and the number of paste B layers N2 in the laminate M are both natural numbers greater than or equal to 1;

[0026] S5. Mix the pre-product C1 or the laminate M with the binder by spraying or dipping, vacuum filter, and dry to obtain a pre-product C3; subject the pre-product C3 to a two-stage programmed heating, followed by cooling, cutting, and packaging to obtain aerogel fiber paper.

[0027] The adhesive is one or more of polyvinyl alcohol, polystyrene, vinyl acetate resin, epoxy resin, polypropylene resin, and silica sol aqueous solution, with a mass concentration of 5% to 10%;

[0028] The fiber matrix is ​​one or more combinations of the pre-product C1, pre-product C2, ceramic fiber paper, glass fiber paper, glass fiber web obtained by non-woven carding, and ceramic fiber web obtained by non-woven carding. The number of fiber matrix layers N1 and the number of paste B layers N2 in the laminate M must satisfy the relationship: N2-1≤N1≤N2+1

[0029] During the papermaking or paper-plastic molding process, the reaction between the slurry and the fiber is achieved by adjusting the vacuum degree, molding pressure, time, temperature, etc.

[0030] Preferably, the stirring and dispersing in step S1 is mechanical stirring, with a rotation speed of 1000 to 5000 r / min and a stirring time of 1 to 5 hours.

[0031] Preferably, the stirring speed in step S2 is 500-1000 r / min, and the stirring time is 0.5-2 h.

[0032] Preferably, the stirring and dispersing in step S3 is mechanical stirring, with a rotation speed of 500 to 1500 r / min and a stirring time of 0.5 to 2.5 h.

[0033] Preferably, the papermaking in step S3 is vacuum papermaking at 0.02-0.10 MPa for 1-5 minutes.

[0034] Preferably, the molding in step S3 is paper molding at 0.5-10 MPa for 0.5-5 minutes.

[0035] Preferably, the size of the pre-product in step S3 is 300*300*(0.5-5) mm, which is controlled during the papermaking or molding process.

[0036] Preferably, the mesh size of the bottom filter screen during the papermaking or molding process in step S3 is 100 to 400 meshes.

[0037] Preferably, the vacuum filtration in step S5 is vacuum filtration at 0.02 to 0.10 MPa for 10 to 30 minutes.

[0038] Preferably, the vacuum filtration in step S5 is bidirectional filtration on both the front and back sides.

[0039] Preferably, the drying in step S5 is microwave drying, the drying temperature is 50-150° C., and the drying time is 10-18 hours.

[0040] Preferably, the programmed temperature increase in step S5 is performed by hot pressing or hot rollers.

[0041] Preferably, the temperature of the programmed heating in step S5 is 200-300° C. in the first stage and 300-600° C. in the second stage.

[0042] The first stage of the programmed temperature increase is to remove residual acid and organic matter in the sample, and the second stage is to transform titanium dioxide from anatase crystal phase to rutile crystal phase.

[0043] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0044] The present invention uses titanium dioxide-based composite aerogel to improve the infrared shielding effect at high temperatures, thereby reducing the thermal conductivity at high temperatures, improving the protective performance of the product, and also improving the uniformity of titanium dioxide in the product; by modifying the fiber, a dehydration reaction is caused between the fiber and the titanium dioxide-based composite aerogel, so that a chemical bond is generated between the fiber and the titanium dioxide-based composite aerogel, rather than a simple physical bond, thereby achieving the effect of enhancing the mechanical properties of the fiber paper; by controlling the diameter and proportion of the fiber, the internal density of the fiber paper can be increased, while achieving better thermal insulation effect; the aerogel fiber paper prepared by this preparation method has high density, good mechanical properties, and strong thermal insulation ability.

[0045] The aerogel fiber paper obtained by the invention has a thickness of 0.5 to 5 mm, a thermal conductivity of ≤0.017 W / (m·K) at room temperature of 25° C., a thermal conductivity of ≤0.033 W / (m·K) at high temperature of 300° C., a tensile strength of ≥0.75 MPa, and a forming rate of 100%. DETAILED DESCRIPTION

[0046] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the embodiments.

[0047] Example 1:

[0048] S1. Mix 700 parts of deionized water and 0.15 parts of polyacrylamide, add 150 parts of modified ceramic fiber, and stir and disperse at a speed of 5000 r / min for 1 hour to obtain slurry A.

[0049] S2. 400 parts of deionized water, 20 parts of titanium dioxide-based composite aerogel powder and 5 parts of PVA were mixed and dispersed at a speed of 1000 r / min for 0.5 h. While stirring, 5 mol / L dilute hydrochloric acid was added in batches until the pH of the paste was between 2 and 3. The mixture was mixed to obtain paste B.

[0050] S3, vacuum papermaking the slurry A described in S1 at 0.10 MPa for 1 minute to obtain a pre-product C2; the mesh size of the bottom filter during the papermaking process is 300 mesh;

[0051] S4. Evenly spray the paste B described in step S2 on the pre-product C2, then alternately layer the pre-product C2 on the surface of the paste B, and vacuum paper-make at 0.10 MPa for 1 minute to obtain a laminate M having a multi-layer "sandwich biscuit" structure with alternating fiber matrix-slurry-fiber matrix;

[0052] S5. Spray 1 portion of silica sol diluted with water to a mass concentration of 10% onto the surface of the laminate M, vacuum filter at 0.10 MPa for 10 minutes, and microwave dry at 150°C for 10 hours to obtain a pre-product C3; hot press the pre-product C3 at 300°C for 2 hours and then at 600°C for 2 hours. After heating, cool, cut, and package to obtain aerogel fiber paper.

[0053] Example 2:

[0054] S1. Stir and disperse 600 parts of deionized water, 0.1 parts of sodium lauryl sulfate, and 50 parts of modified glass fiber at a speed of 1000 r / min for 5 hours to obtain slurry A.

[0055] S2. Mix 200 parts of deionized water, 10 parts of titanium dioxide-based composite aerogel powder and 5 parts of KH550, stir and disperse at a speed of 500 r / min for 2 hours, and add 3 mol / L dilute nitric acid in batches while stirring until the pH of the paste is between 2 and 3. Mix well to obtain paste B;

[0056] S3: vacuum papermaking the slurry A described in S1 at 0.02 MPa for 5 minutes to obtain a pre-product C2; the mesh size of the bottom filter during the papermaking process is 100 mesh;

[0057] S4. Evenly spray the paste B described in step S2 on the pre-product C2, then alternately layer the pre-product C2 on the surface of the paste B, and vacuum paper-make for 5 minutes at 0.02 MPa to obtain a laminate M having a multi-layer "sandwich biscuit" structure with alternating fiber matrix-slurry-fiber matrix;

[0058] S5. Spray 5 parts of polyvinyl alcohol diluted with water to a mass concentration of 7% onto the surface of the laminate M, vacuum filter at 0.02 MPa for 30 minutes, and microwave dry at 50°C for 18 hours to obtain a pre-product C3; hot press the pre-product C3 at 250°C for 3 hours and then at 500°C for 3 hours. After heating, cool, cut, and package to obtain aerogel fiber paper.

[0059] Example 3:

[0060] S1. Mix 700 parts of deionized water and 0.05 parts of polyacrylamide, add 100 parts of modified ceramic fiber, and stir and disperse at a speed of 3500 r / min for 2.5 hours to obtain slurry A;

[0061] S2. 300 parts of deionized water, 5 parts of titanium dioxide-based composite aerogel powder and 3 parts of PVA were mixed and dispersed at a speed of 750 r / min for 1.2 h. While stirring, 0.1 mol / L dilute sulfuric acid was added in batches until the pH of the paste was between 2 and 3. The mixture was mixed to obtain paste B.

[0062] S3, vacuum papermaking the slurry A described in S1 at 0.06 MPa for 3 minutes to obtain a pre-product C2; the mesh size of the bottom filter during the papermaking process is 400 mesh;

[0063] S4. Evenly spray the paste B described in step S2 on the pre-product C2, then alternately layer the pre-product C2 on the surface of the paste B, and vacuum paper-make at 0.06 MPa for 3 minutes to obtain a laminate M having a multi-layer "sandwich biscuit" structure with alternating fiber matrix-slurry-fiber matrix;

[0064] S5. Spray 10 parts of epoxy resin diluted with water to a mass concentration of 5% onto the surface of the laminate M, vacuum filter at 0.06 MPa for 20 minutes, and microwave dry at 100°C for 14 hours to obtain a pre-product C3; hot roll the pre-product C3 at 200°C for 3 hours and then at 450°C for 3 hours. After heating, cool, cut, and package to obtain aerogel fiber paper.

[0065] Example 4

[0066] S1. Mix 700 parts of deionized water and 0.15 parts of polyacrylamide, add 150 parts of modified ceramic fiber, and stir and disperse at a speed of 5000 r / min for 1 hour to obtain slurry A.

[0067] S2. 400 parts of deionized water, 20 parts of titanium dioxide-based composite aerogel powder and 5 parts of PVA were mixed and dispersed at a speed of 1000 r / min for 0.5 h. While stirring, 5 mol / L dilute hydrochloric acid was added in batches until the pH of the paste was between 2 and 3. The mixture was mixed to obtain paste B.

[0068] S3. Slurry A described in S1 and paste B described in S2 were mixed at a speed of 1500 r / min, stirred and dispersed for 0.5 h, and the mixed slurry was vacuum-formed at 0.10 MPa for 1 min to obtain pre-product C1; the mesh size of the bottom filter during the papermaking process was 300 mesh;

[0069] S4, spraying 1 portion of silica sol diluted with water to a mass concentration of 10% onto the surface of the pre-product C1, vacuum filtering at 0.10 MPa for 10 minutes, and microwave drying at 150° C. for 10 hours to obtain the pre-product C3;

[0070] S5. Hot-press the pre-product C3 at 300° C. for 2 h and then at 600° C. for 2 h. After the heating is completed, cool, cut, and package to obtain aerogel fiber paper.

[0071] Example 5:

[0072] The difference from Example 1 is that step S3 is: the slurry A described in S1 is paper-molded for 0.5 minutes at 10 MPa to obtain pre-product C2; the mesh size of the bottom filter during the papermaking process is 300 meshes; step S4 is: evenly spray the paste B described in step S2 on the pre-product C2, and then alternately stack the pre-product C2 on the surface of the paste B, and paper-molded for 0.5 minutes at 10 MPa to obtain a laminate M with alternating fiber matrix-slurry-fiber matrix and a multi-layer "sandwich" structure. Other aspects are the same as Example 1.

[0073] The preparation method of the modified fibers in Examples 1 to 5 is as follows: using a plasma generator to etch the fibers with DBD plasma to obtain modified fibers having hydroxyl groups on the surface.

[0074] The diameters of the fibers used in Examples 1 to 5 were 2 to 10 μm for the ceramic fibers and 1 to 8 μm for the glass fibers, respectively.

[0075] The aerogel modification method in Examples 1 to 5 is as follows: 3 parts of unmodified aerogel powder and 8 parts of n-butyl titanate are added to 150 parts of water, and after uniform dispersion, 1 part of polydiacetylene is added, and dilute hydrochloric acid with a concentration of 1 mol / L is added to adjust the pH to 1 to 3. The mixture is heated at 80°C for 2 hours, and the reaction mixture is centrifuged and dried.

[0076] The unmodified aerogel powder used for aerogel modification in Examples 1 and 4-5 is SiO2 aerogel powder; the unmodified aerogel powder used for aerogel modification in Example 2 is Al2O3 aerogel powder; and the unmodified aerogel powder used for aerogel modification in Example 3 is SiO2-Al2O3 composite aerogel powder.

[0077] The particle size of the unmodified aerogel powder in Examples 1 to 5 is 50 μm; the titanium dioxide in the titanium dioxide-based composite aerogel powder is nanometer-sized.

[0078] Comparative Example 1:

[0079] The difference from Example 1 is that equal parts and proportions of unmodified fibers are used in step S1 , and the rest are the same as in Example 1.

[0080] Comparative Example 2:

[0081] The difference from Example 1 is that equal parts and proportions of unmodified aerogel powder that has not been compounded with titanium dioxide are used in step S2. The rest is the same as in Example 1.

[0082] Comparative Example 3:

[0083] The difference from Example 1 is that unmodified fibers are used in equal parts and proportions in step S1, and unmodified aerogel powder that has not been composited with titanium dioxide is used in equal parts and proportions in step S2. The other parts are the same as those in Example 1.

[0084] Comparative Example 4:

[0085] The difference from Example 1 is that the programmed temperature rise in step S5 is to hot press at 100° C. for 2 hours and then hot press at 150° C. for 2 hours. The other steps are the same as Example 1.

[0086] Comparative Example 5:

[0087] The difference from Example 1 is that the temperature is programmed in step S5 by hot pressing at 400° C. for 2 h and then at 800° C. for 2 h. The other steps are the same as Example 1.

[0088] Comparative Example 6:

[0089] The difference from Example 1 is that the fiber diameter of the modified fiber used in step S1 is 800-1000 μm, and the other parameters are the same as those in Example 1.

[0090] The thickness, thermal conductivity and tensile strength of the aerogel fiber paper prepared in the examples and comparative examples were tested. The thickness was tested using a thickness gauge, the thermal conductivity was tested using a thermal conductivity meter using a heat flow meter method, and the temperature difference between the cold plate and the hot plate did not exceed 30°C; the tensile strength was tested using a universal testing machine. The experimental results are shown in Table 1.

[0091] Table 1

[0092] It can be seen from the test data of Examples 1 to 5 in Table 1 that the aerogel fiber paper provided by the present invention has good thermal insulation performance, and the thermal conductivity is ≤0.017 W / (m·K) at room temperature; at the same time, due to the composite of the aerogel powder used and titanium dioxide, the fiber paper has good infrared shielding performance at high temperatures, and the thermal conductivity is ≤0.033 W / (m·K) at high temperatures; the mechanical properties of the fiber paper are enhanced by the reaction between the modified fiber and the titanium dioxide-based composite aerogel powder, so the tensile strength of the fiber paper is ≥0.75 MPa; at the same time, the preparation process of the aerogel fiber paper provided by the present invention has a forming rate of 100%.

[0093] In Comparative Example 1, since the fiber is not modified, there is no functional group on its surface that reacts with the titanium dioxide-based composite aerogel, and it is only physically bonded, resulting in poor mechanical properties. As a result, the tensile strength of the corresponding sample of Comparative Example 1 is poor.

[0094] In Comparative Example 2, since titanium dioxide is not compounded on the surface of the aerogel powder, its infrared shielding performance at high temperature is poor, which in turn leads to its high thermal conductivity at high temperature.

[0095] In Comparative Example 3, since the fibers and aerogel powder are not modified, the infrared shielding performance and mechanical properties at high temperatures are inferior to those of the embodiment to a certain extent, corresponding to the higher thermal conductivity and poorer tensile strength at high temperatures.

[0096] In Comparative Example 4, due to the low programmed heating temperature, acid and organic matter remained in the sample, and the titanium dioxide crystal form did not complete the transformation, resulting in high thermal conductivity of the sample at room temperature and at high temperature.

[0097] In Comparative Example 5, the temperature is too high, which will lead to energy waste, and the temperature increase within this range does not significantly improve the product performance.

[0098] Comparative Example 6 uses a fiber with a larger diameter and better strength, but its bending resistance is worse than that of the embodiment.

Claims

1. An aerogel fiber paper, characterized in that: By weight parts, the raw materials include 800 - 1100 of deionized water, 0.05 - 0.15 of fiber dispersant, 50 - 150 of modified fiber, 0.3 - 5 of powder surfactant, 0.1 - 90 of titanium dioxide-based composite aerogel powder, 0.1 - 10 of binder, and 3 - 10 of dilute acid.

2. The aerogel fiber paper according to claim 1, wherein: The preparation method of the modified fiber is: the modified fiber obtained by etching the fiber using a plasma generator; The fiber is one or more of ceramic fiber, glass fiber, and organic fiber; The organic fiber is one or more of ultra-high molecular weight polyethylene fiber, polypropylene fiber, polyamide fiber, polyetherimide fiber, polyacrylonitrile fiber, PET fiber, cotton fiber, hemp fiber, soybean fiber, and bamboo fiber 3. The aerogel fiber paper according to claim 1, characterized in that: The preparation method of the titanium dioxide-based composite aerogel powder is: adding unmodified aerogel powder and tetrabutyl titanate into a solvent, dispersing evenly, adding a particle size regulator, reacting at 50 - 80 °C under acidic conditions with a pH of 1 - 3 for 2 - 8 h, centrifuging and separating the reacted mixture and then drying to obtain the titanium dioxide-based composite aerogel powder; The unmodified aerogel powder is one or more of SiO2 aerogel powder, Al2O3 aerogel powder, ZrO2 aerogel powder, SiC aerogel powder, SiO2 - Al2O3 composite aerogel powder, SiO2 - ZrO2 composite aerogel powder, and SiO2 - Al2O3 - ZrO2 composite aerogel powder; The particle size of the unmodified aerogel powder is 5 - 500 μm; The solvent is one or both of deionized water and absolute ethanol.

4. The aerogel fiber paper according to claim 2, characterized in that: The diameter of the ceramic fiber in the fiber is 2 - 10 μm, the diameter of the glass fiber is 1 - 8 μm, and the diameter of the organic fiber is 5 - 15 μm.

5. The aerogel fiber paper according to claim 3, characterized in that: The mass ratio of the unmodified aerogel powder, tetrabutyl titanate, and the particle size regulator is (0.2 - 3):(3 - 8):(0.01 - 1).

6. The aerogel fiber paper according to claim 3, wherein: The particle size regulator is one or more of polybutadiyne, sodium poly(ethylene glycol) alkylaryl ether sulfonate, N,N-dimethylformamide, and 2,5-dihydroxyterephthalic acid; the fiber dispersant is one or both of polyacrylamide and sodium dodecyl sulfate; the powder surfactant is one or both of KH550 and PVA.

7. The aerogel fiber paper according to claim 1, wherein: The dilute acid is an aqueous solution of an acid, and the acid includes one of hydrochloric acid, nitric acid, and sulfuric acid, with a concentration of 0.1 - 5 mol / L.

8. A preparation method of aerogel fiber paper, characterized in that, It includes the following steps: S1. Stir the deionized water and the fiber dispersant evenly, add the modified fiber in proportion, stir and disperse, and mix evenly to obtain slurry A; S2. High-speed mechanically stir the deionized water, the titanium dioxide-based composite aerogel powder, and the powder surfactant at room temperature, mix evenly, add the dilute acid in batches, and adjust the pH to 2 - 3 to obtain paste B; S3. After mixing and stirring the slurry A in S1 and the paste B in S2 evenly, make the mixed slurry into paper by papermaking or into a preform C1 by molding; or directly make the slurry A in S1 into paper by papermaking or into a preform C2 by molding; S4. Uniformly spray or coat the paste B described in S2 above the fiber matrix, and then alternately stack one or more layers of fiber matrix layers on the surface of the paste B in sequence to obtain a laminate M in which the fiber matrix - slurry - fiber matrix appears alternately and has a multi-layered "sandwich biscuit" structure. The number of fiber matrix layers N1 and the number of paste B layers N2 in the laminate M are both natural numbers greater than or equal to 1; S5. Mix the pre-product C1 or the laminate M with the binder by spraying or dipping, perform vacuum filtration, and drying to obtain the pre-product C3; After subjecting the pre-product C3 to a two-stage programmed temperature rise, cool, cut, and package it to obtain the aerogel fiber paper.

9. The method for preparing the aerogel fiber paper according to claim 8, wherein: The binder is one or more of an aqueous solution of polyvinyl alcohol, polystyrene, vinyl acetate resin, epoxy resin, polypropylene resin, and silica sol, and the mass concentration is 5% - 10%.

10. The preparation method of the aerogel fiber paper according to claim 8, wherein: The fiber matrix is one or more combinations of the pre-product C1 described in S3, the pre-product C2, ceramic fiber paper, glass fiber paper, glass fiber web obtained by non-woven carding, and ceramic fiber web obtained by non-woven carding; the number of fiber matrix layers N1 and the number of paste B layers N2 in the laminate M need to satisfy the relationship: N2 - 1 ≤ N1 ≤ N2 + 1.

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