Aluminosilicate aerogel

Abstract

The methods and compositions herein relate to producing aluminosilicate aerogels. The method can include housing a silica precursor in a solvent; hydrolyzing the silica precursor to produce colloidal silica; introducing an aluminum compound into the colloidal silica to produce a colloidal aluminosilicate suspension; converting the aluminosilicate suspension into an aluminosilicate gel composition; and forming an aluminosilicate aerogel by extracting a fluid.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 351,072, filed on June 10, 2022, entitled "HIGH TEMPERATURE AEROGEL MATERIALS COMPRISING ALUMINOSILICATE AEROGELS", the disclosure of which is incorporated herein by reference in its entirety.

[0002] Technical Field The present invention generally relates to aerogel technology. More particularly, in various examples, the present invention relates to methods for manufacturing aluminosilicate aerogels and aluminosilicate aerogel composites.

Background Art

[0003] Low - density aerogel materials are good solid insulators. Aerogels function as insulators mainly by creating tortuous paths for energy transfer through the solid skeleton by minimizing conduction due to their low structural density. Heat transfer through aerogels is also limited by the reduction of convection through large pore volume and very small pore size. Radiation can be limited by dispersing infrared ( "IR") absorbing or scattering dopants throughout the aerogel matrix.

[0004] Aerogels can be used in a wide range of applications, including but not limited to, heating and cooling insulation, acoustic insulation, dielectrics, aerospace, energy storage and production, and filtration. Further, aerogel materials exhibit many other interesting acoustic, optical, mechanical, and chemical properties, and are thus widely useful for a variety of insulating and non - insulating applications. Silica - based aerogels are one type of commonly used aerogel material.

Summary of the Invention

[0005] In some examples, the techniques described herein relate to a method of making an aluminosilicate aerogel, the method comprising: containing a silica precursor in a solvent; hydrolyzing the silica precursor to produce colloidal silica; introducing an aluminum compound into the colloidal silica to produce a colloidal aluminosilicate suspension; converting the aluminosilicate suspension into an aluminosilicate gel composition; and forming an aluminosilicate aerogel by extracting a fluid.

[0006] In some examples, the techniques described herein relate to a method of making an aluminosilicate aerogel, the method comprising: mixing a silica precursor in a solvent to produce a precursor mixture; adding a sol initiator to the precursor mixture to produce colloidal silica; adding an aluminum compound to the colloidal silica to form a colloidal aluminosilicate suspension; adding a gel initiator to the colloidal aluminosilicate suspension to convert the colloidal aluminosilicate suspension into an aluminosilicate gel composition; and forming an aluminosilicate aerogel by extracting a fluid from the aluminosilicate gel composition.

[0007] In some examples, the techniques described herein relate to an aerogel comprising an aluminosilicate comprising an aluminum-containing shell surrounding a silica core, wherein the aerogel has a thermal conductivity of from about 25 to about 30 mW / m·K.

[0008] In drawings that are not necessarily to scale, like numerals represent substantially similar components in some of the figures. Like numerals with different suffixes of letters represent different examples of substantially similar components. The drawings generally illustrate the various examples discussed herein by way of example and not limitation.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Reference will now be made in detail to specific examples of the disclosed subject matter, some of which are illustrated in the accompanying drawings. The disclosed subject matter is described in conjunction with the recited claims, but it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0011] The present disclosure provides compositions and methods for making high-temperature aerogel materials, specifically high-temperature aluminosilicate aerogels. The proposed methods and materials enable higher thermal stability and better protection against significantly higher temperatures and abrasive thermal events compared to non-aluminosilicate aerogel thermal insulation materials. The aerogels discussed herein have low thermal conductivity and excellent acoustic properties. The aerogels discussed herein can be used, for example, in the thermal management of high-density lithium metal batteries where thermal runaway is expected to reach high temperatures of about 1200 °C. This is significantly higher than the breakdown point of silica, a more commonly used aerogel material (about 600 °C).

[0012] An aerogel is a class of porous materials having continuous gas bubbles that include a skeleton of interconnected structures, a corresponding network structure of pores integrated within this skeleton, and an interstitial phase within the network structure of pores that is mainly composed of a gas such as air. Aerogels are typically characterized by low density, high porosity, large surface area, and small pore size. Aerogels can be distinguished from other porous materials by their physical and structural properties. Many potential applications of aerogels, such as in lithium-ion batteries, include environments where high-temperature resistance is desired.

[0013] For example, some aerogel applications require thermal management of temperatures above 600°C, above the breakdown point of silica. In one example, for thermal heat barriers used in battery packs, this is driven by developing battery chemistries with higher energy density. In the event of a thermal runaway event, these higher energy density batteries can produce flame jets and heat loads above 1000°C. Such a thermal runaway event can shut down the entire battery stack in certain devices. This creates a need for a new set of materials that can handle these temperature profiles and thereby prevent one cell in a battery pack experiencing thermal runaway from damaging or initiating thermal runaway on other cells in the battery pack that are not experiencing thermal runaway.

[0014] Thus, the problem to be solved is improved aerogel response to flame impact and reduced thermal conductivity, both of which may be beneficial in certain uses of aerogel materials. Specifically, aerogel material compositions are desired that can help reduce thermal runaway, provide physical resistance to erosion from cell ejection, and enable passive thermal protection to interrupt fire events in vehicles and the like.

[0015] In some cases, silica-based aerogels are used due to their low density and low thermal conductivity. However, silica-based aerogels shrink and densify at 650°C to 950°C, which can form openings through which heat can pass when exposed to high temperatures, such as those encountered during a thermal runaway event in a lithium battery. In other words, silica undergoes rapid thermal expansion, as well as changes in morphology and density, at such high temperatures. Furthermore, such sintering and densification of silica results in cracking or spalling. Sintering and / or densification can cause the edges of the silica aerogel heat shield to shrink, thereby causing cracks and shortening the life of such materials.

[0016] To completely block thermal runaway, heat insulation needs to prevent heat from reaching adjacent cells. Aluminosilicate aerogel has very excellent flame resistance. Furthermore, aluminosilicate aerogel has a low thermal conductivity and, combined with its inherent endothermic solid-phase transition that can function as a heat sink, further prevents the spread of thermal runaway.

[0017] Specifically, aluminosilicate aerogel is a material that can be resistant to temperatures up to 1300 °C. When heated from room temperature to 400 °C, a phase change similar to that of pure alumina occurs from γ-AlO(OH) to γ / η-alumina, and a mass loss due to dehydration occurs. When the heat rises to 1100 °C, the material further undergoes a phase transition through the θ and δ phases of alumina and then reaches α-alumina at 1200 - 1300 °C. These endothermic phase transitions absorb heat, which helps in the effectiveness of aluminosilicate materials in heat management. These characteristics also have the advantage of reducing any physical decomposition mechanisms (such as by shrinkage, densification, etc.), thereby improving the integrity and lifespan of the mesoporous aerogel structure and extending the heat insulation using aluminosilicate aerogel materials. In some cases, aluminosilicate aerogel can be an amalgam aerogel.

[0018] Overall, due to its low thermal conductivity, many endothermic solid-phase transitions, and the ability to maintain physical integrity when exposed to high flame temperatures and abrasive ejecta, aluminosilicate aerogel is an excellent material for use in high-temperature applications.

[0019] However, one problem presented by aluminosilicate aerogel materials is that they have a longer gelation time than that observed with silica aerogel materials. Conventionally, these long gelation times have reduced the manufacturing efficiency and general manufacturability of aluminosilicate materials. For example, in conventional manufacturing methods, it took one hour to form the wet gel network structure of aluminosilicate aerogel compared to the manufacture of conventional silica aerogel, which took only a few minutes. The methods discussed herein significantly reduce the manufacturing time of aluminosilicate aerogels to just a few minutes, similar to that observed with conventional silica aerogel materials, thereby removing one obstacle to the widespread adoption of aluminosilicate materials.

[0020] The proposed methods and compositions provide several advantages, some of which are unexpected. The high-temperature aerogels discussed herein are much more heat resistant than other iterations of silica-based aerogels. In the aerogels discussed herein, the use of reinforcing materials and methods that can have essentially lower heat durability compared to the aerogel itself is further enabled due to the additional thermal stability provided by the aluminosilicate aerogel itself. These less heat-durable reinforcing materials cannot be used in other non-aluminosilicate compositions.

[0021] Furthermore, such aluminosilicate aerogels maintain their thermal conductivity over long-term exposure to high temperatures. Aluminosilicate aerogels, in particular, do not crack at higher temperatures compared to silica-based aerogels. Such aluminosilicate aerogels do not crack and maintain their integrity, and thus do not lose their thermal conductivity over time compared to silica-based aerogels. Thus, over the long term, aluminosilicate aerogels are physically and mechanically more durable (e.g., maintaining the continuity of the porous network structure without cracking and maintaining dimensions and dimensional consistency within + / - 10% of ambient temperature values) even when exposed to high temperatures, unlike other material compositions. Generally, aluminosilicate aerogels are resistant to heat-related decomposition.

[0022] Furthermore, conventional aerogel manufacturing techniques were based on relatively homogeneous liquid-phase chemistry. By comparison, in some of the methods discussed herein, a heterogeneous approach is used that delays the onset of the phase change found in homogeneous aluminosilicates. This can improve the structure of the aerogel when crystallization occurs, improving surface area and porosity while maintaining good thermal properties.

[0023] Furthermore, the proposed method for making aluminosilicate aerogels has a beneficial shorter manufacturing time and uses relatively safe materials. Other techniques for manufacturing aluminosilicate aerogels required more than an hour, but the methods described herein can be done in minutes, resulting in better manufacturing efficiency. The component materials themselves are also safer compared to other precursors and only require handling for a shorter time, resulting in an overall improvement in safety.

[0024] Finally, the aluminosilicate aerogels discussed can be readily used with a variety of beneficial reinforcing materials. Specifically, aluminosilicates can be manufactured with a variety of reinforcing materials, such as fiber or foam-based reinforcing materials, to provide the desired mechanical robustness. Such composite materials are constructible and durable. However, even when no reinforcing material is used, aluminosilicate aerogels can be relatively resilient and durable, for example, in a battery environment, due to their high heat capacity.

[0025] Exemplary methods for making aluminosilicate aerogels and exemplary aluminosilicate aerogels themselves are discussed herein.

[0026] Method for Making Aluminosilicate Aerogel In the exemplary methods described herein, aerogel materials for high-temperature applications can be produced. Some of the aluminosilicate aerogel materials described herein may include a silica shell grown on an alumina core. To produce this aerogel, at a desired transient point during the manufacturing process, a mechanical advantage can be created in the aerogel by combining an alumina compound (e.g., boehmite) with silica. At a high level, a silica precursor, such as a silicate, can be fully hydrolyzed. Thereafter, during the casting step, an alumina compound such as boehmite can be added to the hydrolyzed silica precursor. Various additives can optionally be added at this point. Then, by appropriately aging the aerogel, a continuous three-dimensional nanoporous network structure of aluminosilicate strands defining a nanoporous network structure can be produced.

[0027] An aluminosilicate aerogel can be formed by combining a silica gel precursor or a combination of a silica gel and an aluminum compound. In one example, the process of forming an aluminosilicate aerogel can include: 1) providing a precursor mixture comprising a silica gel precursor and a solvent; 2) adding a sol initiator to the precursor mixture, where in the presence of the sol initiator, the silica gel precursor is hydrolyzed to form colloidal silica; 3) adding an aluminum compound to the precursor mixture to produce a colloidal aluminosilicate suspension and optionally casting this material into a reinforcing material; 4) adding a gel initiator to the colloidal silica suspension, where in the presence of the gel initiator, the colloidal aluminosilicate suspension is converted into an aluminosilicate gel composition; and 5) extracting fluid from the aluminosilicate gel composition to form an aluminosilicate aerogel composition.

[0028] Various approaches for manufacturing aluminosilicate aerogels: The core / shell method, the composite sol method, or the addition method can be used. In the first method (core / shell), during the hydrolysis of the silica precursor, an aluminum-containing compound can be added to coincide with the exothermic peak of the hydrolysis reaction. In the second method (composite sol), the aluminum-containing compound can be added at the end of hydrolysis. In the third method, an aluminum-containing compound can be added while casting the aerogel onto a reinforcing material.

[0029] These processes are described in more detail below. However, the specific examples and figures provided herein are not intended to limit the present disclosure to any particular type of aerogel and / or method of preparation. The present disclosure can include any aerogel formed by any related method of preparation known to those skilled in the art.

[0030] Detailed exemplary embodiments Silica precursor. The silica precursor is provided, received, or prepared. In some cases, the silica precursor can be pre-prepared and easily received by the operator preparing the aluminosilicate aerogel. For example, a precursor mixture can be received in a solvent. Such a mixture can include both the silica precursor compound itself and one or more suitable solvents.

[0031] Examples of silica gel precursor materials for silica-based aerogel synthesis include, but are not limited to, metal silicates such as sodium silicate or potassium silicate; alkoxysilanes such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), and tetra-n-propoxysilane; partially hydrolyzed alkoxysilanes such as partially hydrolyzed TEOS and partially hydrolyzed TMOS; condensation polymers of alkoxysilanes such as condensation polymers of TEOS and condensation polymers of TMOS; alkylalkoxysilanes, and combinations thereof.

[0032] Specific examples of silica gel precursors include, but are not limited to, triethyl orthosilicate (TEOS), trimethyl orthosilicate (TMOS), methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDES), trimethylmethoxysilane (TMS), dimethyldimethoxysilane (DMS), trimethylethoxysilane, ethyltriethoxysilane (ETES), diethyldiethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane (PhTES), hexamethyldisilazane, and hexaethyldisilazane.

[0033] In certain examples of the present disclosure, pre-hydrolyzed TEOS such as Silbond H-5 (SBH5, Silbond Corp) hydrolyzed at a water / silica ratio of about 1.5 - 2 may be used commercially or may be further hydrolyzed before being incorporated into the gelation process. Partially hydrolyzed TEOS or TMOS, such as polysilicate (Silbond 40) or polymethylsilicate, may be used commercially or may be further hydrolyzed before being incorporated into the gelation process.

[0034] In one example, the first step of forming an aluminosilicate aerogel composition generally involves forming a silica gel precursor solution by hydrolysis and condensation of a silicon alkoxide precursor in an alcoholic solvent. The main variables in the formation of a silica-based aerogel include the type of silicon alkoxide precursor contained in the precursor solution, the nature of the solvent, the processing temperature and pH of the precursor solution (which can be altered by addition of an acid or base), and the precursor / solvent / water ratio in the precursor solution. Control of these variables in the formation of the precursor solution can enable control of the growth and aggregation of the gel skeleton during the subsequent transition of the gel material from the "sol" state to the "gel" state. The properties of the resulting aerogel are affected by the pH of the precursor solution and the molar ratio of the reactants, but any pH and any molar ratio that enable gel formation can be used in the present disclosure.

[0035] At least one silica precursor is combined with a solvent to form a precursor mixture. Suitable solvents for use in forming the precursor mixture include lower alcohols having 1 to 6 carbon atoms, preferably 2 to 4 carbon atoms, although other solvents can also be used as known to those skilled in the art. Examples of useful solvents include, but are not limited to, methanol, ethanol, isopropanol, ethyl acetate, ethyl acetoacetate, acetone, dichloromethane, tetrahydrofuran, and the like. A combination of multiple solvents can also be used to achieve a desired level of dispersion or to optimize the properties of the gel material. Thus, the selection of the optimal solvent for the sol-gel and gel formation steps depends on the specific precursors, fillers, and additives incorporated into the sol-gel solution, as well as the target processing conditions for gelation and liquid phase extraction, and the desired properties of the final aerogel material.

[0036] In the case of silica precursors, the solvent-to-silica ratio can be varied to control the molecular weight and silica percent solids of the mixture. When hydrolyzed in the next step, the solvent-to-silica ratio can also be manipulated to adjust the acid content in the mixture.

[0037] Hydrolysis. The silica precursor is hydrolyzed to form colloidal silica. In one example, this can include adding a sol initiator to the precursor mixture. The sol initiator can be, for example, hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, oxalic acid, acetic acid, or a combination thereof. The sol initiator can be added before introducing the aluminum compound. In one example, the silica precursor can be completely hydrolyzed before the introduction of the aluminum compound.

[0038] In one example, water can be present in the precursor solution. Water serves to hydrolyze the metal alkoxide precursor to a metal hydroxide precursor. The hydrolysis reaction can be (using TEOS in an ethanol solvent as an example) as follows. Si(OC2H5)4 + 4H2O → Si(OH)4 + 4(C2H5OH) (1)

[0039] The resulting hydrolyzed metal hydroxide precursor remains suspended in the precursor solution in a "sol" state, as individual molecules or as small polymeric (or oligomerized) colloidal clusters of molecules. For example, the polymerization / condensation of the Si(OH)4 precursor can occur as follows: 2Si(OH)4--- * (OH)3Si-O-Si(OH)3+H2O (2)

[0040] This polymerization can continue until colloidal clusters of polymerized (or oligomerized) SiO2 (silica) molecules are formed. The ratio of silica gel precursor to water is in the range of about 1.0 to about 2.5. In one embodiment, the ratio of silica gel precursor to water is about 1.8. In one embodiment, the silica gel precursor is partially hydrolyzed. The degree of hydrolysis can be measured by the solids content of the partially hydrolyzed silica gel precursor. In some embodiments, the solids content of the partially hydrolyzed silica gel precursor is about 10% to about 30% silicon dioxide.

[0041] To control the pH of the precursor mixture, acids and bases can be added to the precursor mixture. The acid or base can be used as a sol initiator. The sol initiator catalyzes the hydrolysis and condensation reactions of the silica gel precursor material and converts the silica gel precursor material into colloidal silica suspended in a solvent. In one example, the sol initiator is an acid. Any acid can be used as a sol initiator and to obtain a relatively low pH precursor mixture, but preferred acids include HCl, H2SO4, H3PO4, nitric acid, oxalic acid, and acetic acid.

[0042] Addition of an aluminum compound. After hydrolysis, an aluminum compound can be added to the precursor mixture to produce a colloidal aluminosilicate suspension. The timing of the addition of the aluminum compound may affect the final structure of the aluminosilicate aerogel. For example, silica growth and the formation of the silica network structure can occur separately from alumina growth and the formation of the alumina network structure. If silica is hydrolyzed first, the silica network structure can grow first and capture the aluminum compound therein. This enables the formation of a mechanically beneficial core / shell structure. Such aluminum compounds can include boehmite, pseudoboehmite, alumina, aluminum trihydroxide, aluminum-alkoxide, aluminum hydrocarboxylic acid species, or combinations thereof.

[0043] For example, after hydrolyzing a silica gel precursor, an aluminum compound is added to the mixture. Examples of aluminum compounds that can be added to the precursor mixture include, but are not limited to, boehmite, pseudoboehmite, alumina, aluminum trihydroxide, aluminum-alkoxide, and aluminum hydrocarboxylic acid species. A colloidal aluminosilicate suspension is produced by adding the aluminum compound during the hydrolysis of the silica gel precursor or after converting the silica gel precursor to a colloidal silica suspension.

[0044] An aluminum compound is an amphoteric compound, i.e., a compound that reacts with both a base and an acid. When an acid or a base is used as a sol initiator to catalyze the hydrolysis of the silica gel precursor, the initiator can react with any aluminum compound present in the mixture. The aluminum compound reacts with the acid or the base and gels rapidly, preventing the aluminum compound from being incorporated into the silica skeleton in a way that improves the heat resistance of the resulting aerogel. To avoid gelling of the aluminum compound, after initiating the hydrolysis of the silica gel precursor to produce a colloidal aluminosilicate suspension, the aluminum compound is added to this precursor mixture.

[0045] In one example, an aluminum compound is added to the precursor mixture approximately (+ / -10%) 1 minute to approximately 1 hour after combining a sol initiator (e.g., an acid) with a silica gel precursor. Without being bound by any theory, it is believed that the delayed addition of the aluminum compound avoids an undesirable reaction between the aluminum compound and the sol initiator (e.g., an acid and water). Also, by adding the aluminum compound after the start of hydrolysis, the aluminum compound is coated with a partially hydrolyzed silica gel precursor, and it is believed that a shell / core composite is formed with the aluminum compound as the core and the hydrolyzed silica gel precursor as the shell. The shell of the hydrolyzed silica gel precursor protects the aluminum compound core from reacting with a gel initiator (typically a base) in a subsequent gelation reaction.

[0046] In another example, an aluminum compound is added to the precursor mixture approximately 1 hour to approximately 24 hours after combining a sol initiator (e.g., an acid) with a silica gel precursor. In this example, the aluminum compound is added to the precursor mixture after substantial hydrolysis of the silica gel precursor is nearly complete. Without being bound by any theory, it is believed that adding the aluminum compound at the end of the hydrolysis reaction avoids an undesirable reaction between the aluminum compound and the sol initiator (e.g., an acid). Also, by adding the aluminum compound after hydrolysis is complete or nearly complete, the aluminum compound binds with a silica precursor of an appropriate molecular weight, thereby sufficiently changing the surface of the aluminum compound so that the aluminum compound can withstand subsequent exposure to a gel initiator (e.g., a base). The mixture may be stirred or agitated to facilitate the binding of the aluminum compound to the hydrolyzed silica gel precursor.

[0047] The hydrolysis time can be varied to change the molecular weight. The molecular weight can be changed by controlling the temperature of hydrolysis.

[0048] Gelation. The colloidal suspension can be converted into an aluminosilicate gel composition by the addition of a gel initiator such as, for example, a metal hydroxide base or an amine base.

[0049] In one example, after the addition of the aluminum compound is complete and the hydrolysis reaction has substantially ended, the obtained colloidal aluminosilicate suspension is converted into an aluminosilicate gel composition by adding a gel initiator to the suspension. The gel initiator can be an acid or a base that catalyzes the gelation reaction of silica. Typically, the gel initiator is a base. Any base can be used as the gel initiator. In one example, a metal hydroxide base can be used to catalyze the gelation reaction. Exemplary metal hydroxide bases include, but are not limited to, sodium hydroxide, lithium hydroxide, calcium hydroxide, potassium hydroxide, strontium hydroxide, and barium hydroxide. In another example of the present disclosure, an amine base can be used as the gel initiator. Exemplary amine bases include, but are not limited to, tetraalkylammonium hydroxide, choline hydroxide, trialkylamine, amidine, guanidine, and imidazole. Specific examples of amine bases include tetramethylammonium hydroxide, tetrabutylammonium hydroxide, guanidine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), pyridine, imidazole, and 4,5-dihydroimidazole.

[0050] The resulting aluminosilicate gel composition can include additional co-gelation precursors, as well as filler materials and other additives. The filler materials and other additives can be dispensed into the precursor solution or into any of the intermediate mixtures at any point before or during the formation of the gel. The filler materials and other additives can also be incorporated into the gel material after gelation by various techniques known to those skilled in the art. Preferably, the precursor solution containing the silica gel precursor, aluminum compound, solvent, catalyst, water, filler materials and other additives is a homogeneous solution capable of effective gel formation under suitable conditions. The process of converting the colloidal aluminosilicate suspension to an aluminosilicate gel includes an initial gel formation step in which the gel solidifies to the gel point of the gel material. The gelation point of the gel material can be considered the point at which the gelling solution exhibits resistance to flow and / or forms a substantially continuous polymer backbone throughout its volume. Various gel formation techniques are known to those skilled in the art. By way of example and not limitation, maintaining the mixture in a static state for a sufficient time; adjusting the pH of the solution; adjusting the temperature of the solution; directing a form of energy at the mixture (ultraviolet, visible light, infrared, microwave, ultrasonic, particle radiation, electromagnetic radiation); or combinations thereof.

[0051] Reinforcing materials. In some cases, the aluminosilicate aerogel can be made directly on one or more reinforcing materials. In some embodiments, this can be achieved by dispersing the colloidal aluminosilicate suspension on the reinforcing material prior to converting the aluminosilicate suspension to the aluminosilicate gel composition. In some embodiments, this can be achieved by dispersing colloidal silica on the reinforcing material and simultaneously introducing an aluminum compound. Such reinforcing materials can be, for example, fibrous materials or foamed materials.

[0052] For example, the gel materials of the present disclosure can be manufactured by a continuous casting and gelation process. In the continuous casting process, a continuous sheet of fiber material or foamed material can be used as a support during the continuous casting process. The fibrous support can improve the flexibility and / or strength of the aerogel material. In one example of the present disclosure, a fiber-supported wet gel material is formed by adding a gel precursor composition, typically a colloidal composition, to a fiber reinforcing material and forming a wet gel from the gel precursor composition when disposed on the fiber reinforcing material. In this method, the wet gel material formed from the gel precursor composition is integrated into the fiber reinforcing material.

[0053] In some embodiments, the aluminosilicate wet gel material can be formed in a casting process, preferably a continuous casting process. In this method, a precursor mixture containing a silica gel precursor and a solvent is obtained. As described above, a sol-initiator is added to the silica gel precursor mixture to initiate hydrolysis of the silica gel precursor. When hydrolysis of the silica gel precursor is substantially complete, the resulting colloidal silica is dispersed on a fiber reinforcing material. Before, during, or after dispersing the colloidal silica on the fiber reinforcing material, an aluminum compound is mixed with the colloidal silica to form an aluminum compound-containing colloidal silica suspension.

[0054] In some embodiments, an aluminum compound can be combined with the colloidal silica in a step prior to dispersion of the colloidal silica onto the fiber reinforcing material. In another example, the colloidal silica and the aluminum compound are placed in a casting device. In the casting device, the colloidal silica and the aluminum compound are applied to the fiber reinforcing material substantially simultaneously. In this example, the colloidal silica and the aluminum compound may be mixed within the casting device, or a colloidal silica-aluminum compound mixture may be applied to the fiber reinforcing material.

[0055] In some embodiments, the casting device sequentially applies colloidal silica and an aluminum compound to the fiber reinforcement material. In this example, the casting device may first apply colloidal silica to the fiber reinforcement material. After applying the colloidal silica, the aluminum compound is applied. In an alternative example of this case, the order can be reversed. In the reverse method, the aluminum compound is first applied to the fiber reinforcement material, and then colloidal silica is applied.

[0056] Here, a gel initiator is added to the aluminum compound containing the colloidal silica suspension disposed on the fiber reinforcement material. The gel initiator catalyzes the conversion of the aluminum compound containing the colloidal silica suspension into an aluminosilicate gel composition.

[0057] In some embodiments, the aluminosilicate wet gel material can be formed in a casting process, preferably a continuous casting process. In this alternative method, a precursor mixture containing a silica gel precursor and a solvent is obtained. As described above, a sol - initiator is added to the silica gel precursor mixture to initiate hydrolysis of the silica gel precursor. The aluminum compound is added to the precursor mixture before hydrolysis is complete, as described above. The aluminum compound can be added near the start or near the end of hydrolysis. When hydrolysis of the aluminum compound / silica gel precursor is substantially complete, the resulting colloidal aluminosilicate is dispersed on the fiber reinforcement material. A gel initiator is added to the colloidal alumina / silica suspension disposed on the fiber reinforcement material. The gel initiator catalyzes the conversion of the aluminum compound containing the colloidal silica suspension into an aluminosilicate gel composition.

[0058] In some embodiments of the large-scale manufacture of aerogels, the fiber reinforcement material is in the form of a continuous sheet of interconnected or combined fiber reinforcement materials. The precursor solution is incorporated into the continuous sheet of interconnected or combined fiber reinforcement materials. The initial wet gel material is produced as a continuous sheet of fiber-reinforced gel by casting or impregnating the gel precursor solution into the continuous sheet of interconnected or combined fiber reinforcement materials. This technique can be applied to individual sheets of fiber (or foam) reinforcement materials having equivalent effectiveness. As described in more detail, the liquid phase can then be at least partially extracted from the fiber-reinforced wet gel material to produce a sheet-like fiber-reinforced aerogel composite.

[0059] The aerogel composite material may be fiber-reinforced with various fiber-reinforcing materials in order to obtain a more flexible, elastic, and conformable composite product. The fiber-reinforcing materials may be in the form of individual fibers, woven fabric materials, non-woven fabric materials, batting, webs, mats, scrims, and felts. The fiber-reinforcing materials can be manufactured from organic fiber materials, inorganic fiber materials, or combinations thereof. The fiber-reinforcing materials may include, but are not limited to, the following various materials: polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate (e.g., rayon, nylon), cotton (e.g., Lycra (manufactured by DuPont)), carbon (e.g., graphite), polyacrylonitrile (PAN), oxidized PAN, non-carbonized heat-treated PAN (e.g., manufactured by SGL carbon), fiberglass-based materials (e.g., S-glass, 901 glass, 902 glass, 475 glass, E-glass), silica-based fibers such as quartz (e.g., Quartzel (manufactured by Saint-Gobain)), Q-felt (manufactured by Johns Manville), Saffil (manufactured by Saffil), Durablanket (manufactured by Unifrax), and other silica fibers, Duraback (manufactured by Carborundum), polyaramid fibers, e.g., Kevlar, Nornex, Sontera (all manufactured by DuPont), Conex (manufactured by Taijin), polyolefins, e.g., Tyvek (manufactured by DuPonl), Dyneema (manufactured by DSM), Spectra (manufactured by Honeywell), other polypropylene fibers, e.g., Typar, Xavan (both manufactured by DuPont), fluoropolymers, e.g., PTFE having the trade name Teflon (manufactured by DuPont), Goretex (manufactured by \V.L.GORE), silicon carbide fibers, e.g., Nicalon (manufactured by COI Ceramics), ceramic fibers, e.g., Nextel (manufactured by 3M), acrylic polymers, wool fibers, silk, hemp, leather, suede, PBO-Zylon fibers (manufactured by Tyobo), liquid crystal materials, e.g., Vectan (manufactured by Hoechst), Cambrel fibers (manufactured by DuPont), polyurethanes, polyamides, metal fibers, e.g., boron, aluminum, iron, stainless steel fibers, and thermoplastic resins, e.g., PEEK, PES, PEI, PEK, PPS.The aerogel can be reinforced on a foamed material. The foam is a series of interconnected struts, forming a structure of open cells and closed cells. The foam can be an inorganic foam (such as alumina, silicon carbide, etc.), an organic foam (such as melamine, polyurethane, PEI, carbon, etc.), or a metal foam. The aerogel composite of the present disclosure can have a thickness of 15 mm or less, 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less.

[0060] Fluid extraction. After gelation, the aluminosilicate aerogel can be formed by extracting excess fluid through a supercritical extraction process or the like.

[0061] In an example of the present disclosure, the aerogel composite may include an opacifying additive to reduce the radiative component of heat transfer. At any point before gel formation, an opacifying compound or its precursor may be dispersed in a mixture containing the gel-forming material. Exemplary opacifying additives include, but are not limited to, B4C, diatomaceous earth, manganese ferrite, MnO, NiO, SnO, indium tin oxide, Ag20, Bh03, TiC, WC, carbon black, titanium oxide, iron titanium oxide, zirconium silicate, zirconium oxide, iron(I) oxide, iron(III) oxide, manganese dioxide, iron titanium oxide (ilmenite), chromium oxide, silicon carbide, or a mixture thereof. The opacifying additive can be added at any stage of the process for forming the aerogel. Preferably, the addition of the opacifying additive is carried out at the colloidal silica stage, the colloidal aluminosilicate stage, or added to the aluminosilicate wet gel material.

[0062] The process of transferring the gel-forming component to the gel material can also include an aging step (also called curing) before liquid phase extraction. By performing aging after the gel material has reached its gel point, the number of cross-links within the network structure can be increased, thereby further strengthening the gel skeleton. The aging period of the gel can be adjusted to control various properties within the resulting aerogel material. This aging procedure can be useful for preventing potential volume loss and shrinkage during liquid phase extraction. Aging can involve maintaining the gel (before extraction) in a static state for an extended period; maintaining the gel at an elevated temperature; adding cross-linking promoting compounds; or any combination thereof.

[0063] Aging. Optionally, the aluminosilicate gel composition can be aged prior to forming the aluminosilicate aerogel. For example, aging of the aluminosilicate gel composition can include heating the aluminosilicate gel composition at a temperature of 60°C to 120°C. For example, aging of the aluminosilicate gel composition can be carried out over a time range of about 1 hour to about 24 hours.

[0064] The period of transferring the gel-forming material to the gel material includes both the initial gel-forming period (from the start of gelation to the gel point) and any subsequent curing and aging period of the gel material before liquid phase extraction (from the gel point to the start of liquid phase extraction). The total period for transferring the gel-forming material to the wet gel material is typically from about 1 minute to several days, preferably 30 hours or less, 24 hours or less, 15 hours or less, 10 hours or less, 6 hours or less, 4 hours or less, 2 hours or less, 1 hour or less, 30 minutes or less, or 15 minutes or less. Ideally, the total period is minimized to enable efficient production of the aerogel.

[0065] Aging of the wet gel material can be achieved by heating the wet gel material for a time sufficient to complete the aging process. In a typical aging process, the wet gel material is placed in an aging vessel. The wet gel material is then heated to the aging temperature and maintained at the aging temperature until the aging process is complete. Optionally, the wet gel material can be washed with an aging fluid before and during heating. The aging fluid can be used to replace the primary reaction solvent present in the wet gel. Exemplary aging fluids are water, C1-C6 alcohols, cyclic alcohols, cycloaliphatic alcohols, aromatic alcohols, polyhydric alcohols, ethers, ketones, cyclic ethers, or any combination thereof. Preferred aging fluids include water, methanol, and ethanol. During aging, the aging fluid can pass substantially continuously over and / or through the wet gel material and through the aging vessel. The aging fluid passing through the aging vessel and the wet gel can be fresh aging fluid or recycled aging fluid.

[0066] Once the gel material is formed and aged, the liquid phase of the gel can then be at least partially extracted from the aluminosilicate wet gel using an extraction method to form an aerogel material. Liquid phase extraction plays a role in designing the characteristics of the aerogel, such as porosity and density, as well as related properties, such as thermal conductivity, among other factors. Generally, an aerogel is obtained when the liquid phase is extracted from the gel in a way that causes low shrinkage to the porous network structure and skeleton of the wet gel.

[0067] Formation of aerogel. An aerogel is typically formed by removing a liquid mobile phase from a gel material at a temperature and pressure near or above the critical point of the liquid mobile phase.

[0068] When reaching (near the critical point) or exceeding (supercritical), i.e., when the pressure and temperature of the system are above the critical pressure and critical temperature respectively, a new supercritical phase appears in a fluid different from the liquid phase or the vapor phase. Then the solvent can be removed without introducing a liquid-vapor interface, capillary pressure, or any associated mass transfer limitations typically associated with the liquid-vapor boundary. Furthermore, the supercritical phase is generally more miscible with organic solvents and thus has better extraction ability. Cosolvents and solvent exchange are also commonly used to optimize the supercritical fluid drying process.

[0069] In an example of extracting the liquid phase from a wet gel, supercritical conditions of carbon dioxide are used, for example, first substantially exchanging the primary solvent present in the pore network structure of the gel with liquid carbon dioxide, heating the wet gel above the critical temperature of carbon dioxide (about 31.06 °C), and increasing the pressure of the system above the critical pressure of carbon dioxide (about 1070 psig). The pressure around the gel material can be slightly varied, which facilitates the removal of the supercritical carbon dioxide fluid from the gel. Carbon dioxide can be recycled through the extraction system, which facilitates the continuous removal of the primary solvent from the wet gel.

[0070] Finally, to produce the dried aerogel material, the temperature and pressure are slowly returned to ambient conditions. Carbon dioxide can also be pretreated to a supercritical state before being injected into the extraction chamber. Further details regarding the synthesis of aerogels from wet gel materials can be found in U.S. Patent Application Publication No. 2016 / 0096949 by Evans et al. and U.S. Patent Application Publication No. 2021 / 03095227 by Evans et al., both of which are incorporated herein by reference.

[0071] Aluminosilicate aerogel The methods discussed herein can be used to produce useful aluminosilicate aerogel materials. Such aerogels can contain aluminosilicates. The aerogel can be a core-shell material, with a silica network structure, for example, around an alumina network structure, as can be seen in cross-section.

[0072] The aluminosilicate aerogels discussed herein can have a thermal conductivity of about 20.0 to about 30.0 mW / m·K, about 21.0 to about 29.0, about 22.0 to about 28.0, about 23.0 to about 27.0, about 24.0 to about 26.0, or about 25.0 mW / m·K.

[0073] The aluminosilicate aerogels discussed herein can have a surface area of at least about 60.0 m 2 / g. In one example, the aluminosilicate aerogels discussed herein can have a surface area greater than at least about 55.0, 60.0, 65.0, 70.0, 75.0, 80.0, 85.0, 90.0, 95.0, 100.0, 105.0, or 110.0 m 2 / g.

[0074] The aluminosilicate aerogels discussed herein can have an average pore size of about 60 to about 70 Å, about 61 to about 69, about 62 to about 68, about 63 to about 67, about 64 to about 66, or about 65 Å.

[0075] The aluminosilicate aerogels discussed herein can have a pore volume of about 0.10 to about 0.17 cm 3 / g, about 0.11 to about 0.16, about 0.12 to about 0.15, or about 0.13 to about 0.14 cm 3 / g.

[0076] The aluminosilicate aerogels discussed herein can have a density of about 0.200 to about 0.300 g / cc, about 0.210 to about 0.290, about 0.220 to about 0.280, about 0.230 to about 0.270, about 0.240 to about 0.260, or about 0.250 g / cc.

[0077] The aerogel composite of the present disclosure can have a thickness of 15 mm or less, 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less.

[0078] Battery module having an aluminosilicate aerogel The aluminosilicate aerogels discussed herein can be used in various thermal insulation applications, such as for battery thermal management. In one example use, the aluminosilicate aerogel composite can be used as thermal insulation between individual battery cells or groups of battery cells. Battery cells are prone to catastrophic failure under "abusive use conditions". Abusive use situations include mechanical abuse, electrical abuse, and thermal abuse. One or all of these abusive use conditions can be initiated externally or internally. For example, supply-induced stress, aging, design errors, such as cell spacing, cell interconnection style, cell form factor, manufacturing, operation, and maintenance, etc. are internal mechanical factors that can cause various types of abusive use. External mechanical factors include, for example, damage or scratches to the LIB due to dropping or penetration of the cell. Electrical abusive use conditions mainly include internal short circuit or external short circuit, overcharging, and over-discharging of the battery cell. Thermal abuse is typically caused by overheating. For example, overheating in a battery cell can be caused by operating the battery cell at a high ambient temperature. Internally, electrical and mechanical defects in the battery cell can cause thermal abuse.

[0079] In the case of a thermal runaway event, these higher energy densities can result in flame jets and heat loads above 1000 °C. This creates a need for new materials that can handle these temperature profiles. Aluminosilicate aerogel composites with a maximum service temperature of about 1200 - 1300 °C have been found to be useful in preventing high-temperature runaway events in energy storage systems. When heated from room temperature to 400 °C, a phase change occurs from y-AlO(OH) to γ / η-alumina, accompanied by mass loss and dehydration, following the behavior of pure alumina. When the heat rises to 1100 °C, the aluminosilicate composite passes through the θ and δ phases of alumina and ends up in α-alumina at 1200 - 1300 °C. These phase transitions are useful for thermal management and do not destroy the mesoporous aerogel structure.

[0080] Battery modules and battery packs can be used to supply electrical energy to a device or vehicle. Devices that can use a battery module or battery pack include, but are not limited to, the following: laptop computers, PDAs, mobile phones, tag scanners, audio devices, video devices, display panels, video cameras, digital cameras, desktop computers, military portable computers, military phones, laser rangefinders, digital communication devices, information collection sensors, electronically integrated apparel, night vision devices, power tools, calculators, radios, remote control devices, GPS devices, handheld and portable TVs, automotive starters, flashlights, audio systems, portable heating devices, portable vacuum cleaners, or portable medical devices. When used in a vehicle, the battery pack can be used in all electric or hybrid vehicles.

[0081] Definitions As used herein, the term "about" can tolerate variations in a value or range, e.g., within 10%, within 5%, or within 1% of the stated limitations of the stated value or range, and includes that stated value or range.

[0082] As used herein, the terms "aerogel" or "aerogel material" refer to a gel that includes a framework of interconnected structures having a corresponding network structure of interconnected pores integrated within the framework and containing a gas such as air as a dispersed interstitial medium. Aerogel materials are characterized by the following physical and structural properties (in accordance with a nitrogen intrusion test): (a) an average pore diameter in the range of about 2 nm to about 100 nm, (b) a porosity of at least 80% or more, and (c) a surface area of about 20 m 2 / g or more. Aerogels or aerogel materials include any aerogel, aerogel material, or other continuous cellular compound that meets the elements of these definitions, including compounds that may be separately classified as xerogels, cryogels, ambigels, microporous materials, etc. Aerogel materials may further be characterized by additional physical properties including: (d) a pore volume of about 2.0 mL / g or more, preferably about 3.0 mL / g or more; (e) a density of about 0.50 g / cc or less, preferably about 0.25 g / cc or less; (f) at least 50% of the total pore volume comprising pores having a pore diameter of 2 - 50 nm, although meeting these additional properties is not necessary to characterize a compound as an aerogel material. The aerogel framework can be made from a series of precursor materials including inorganic precursor materials (e.g., precursors used in the manufacture of silica-based aerogels), organic precursor materials (e.g., precursors used in the manufacture of carbon-based aerogels), hybrid inorganic / organic precursor materials, and combinations thereof.

[0083] In the context of the present disclosure, the term "amalgam aerogel" refers to an aerogel produced from a combination of two or more different gel precursors.

[0084] In the context of the present disclosure, the term "mesoporous aerogel structure" refers to an aerogel having a three-dimensional interconnected network structure that defines a network structure of pores.

[0085] In the context of the present disclosure, the terms "skeleton" or "skeletal structure" refer to a network structure of interconnected oligomers, polymers, or colloidal particles that form the solid structure of a gel or aerogel. The polymers or particles that make up the skeletal structure typically have a diameter of about 100 angstroms. However, the skeletal structures of the present disclosure may also include network structures of interconnected oligomers, polymers, or colloidal particles of all diameter sizes that form a solid structure within the gel or aerogel.

[0086] As used herein, the term "air" generally refers to a mixture of gases having a composition substantially the same as the natural composition of the gases taken in from the atmosphere, at or near ground level. In some examples, air is taken in from the surrounding environment. Air has a composition that includes about 78% nitrogen, 21% oxygen, 1% argon, and 0.04% carbon dioxide, along with small amounts of other gases.

[0087] As used herein, the term "alkoxy" refers to an oxygen atom bonded to an alkyl group, such as a cycloalkyl group as defined herein. Examples of straight-chain alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, and the like. Examples of branched alkoxy groups include, but are not limited to, isopropoxy, sec-butoxy, tert-butoxy, isopentyloxy, isohexyloxy, and the like. Examples of cyclic alkoxy groups include, but are not limited to, cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, and the like. An alkoxy group may include from about 1 to about 12, from about 1 to about 20, or from about 1 to about 40 carbon atoms bonded to the oxygen atom, may further include double or triple bonds, and may also include heteroatoms. For example, an allyloxy group or a methoxyethoxy group is also an alkoxy group within the meaning of this specification, and in the context where two adjacent atoms of a structure are substituted with these, it is a methylenedioxy group.

[0088] As used herein, the term "alkyl" refers to straight-chain and branched-chain alkyl groups and cycloalkyl groups having from 1 to 40 carbon atoms, from 1 to about 20 carbon atoms, from 1 to 12 carbons, or in some instances from 1 to 8 carbon atoms. Examples of straight-chain alkyl groups include those having from 1 to 8 carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples of branched-chain alkyl groups include, but are not limited to, isopropyl, isobutyl, sec-butyl, t-butyl, neopentyl, isopentyl, and 2,2-dimethylpropyl groups. As used herein, the term "alkyl" encompasses n-alkyl, isoalkyl, and anteisoalkyl groups, as well as other branched-chain forms of alkyl. Representative substituted alkyl groups can be substituted one or more times with any of the groups listed herein, for example, amino, hydroxy, cyano, carboxy, nitro, thio, alkoxy, and halogen groups.

[0089] As used herein, the term "alkynyl" refers to straight-chain and branched-chain alkyl groups except that at least one triple bond exists between two carbon atoms. Thus, alkynyl groups have from 2 to 40 carbon atoms, from 2 to about 20 carbon atoms, or from 2 to 12 carbons, or in some instances from 2 to 8 carbon atoms. For example, but not limited to, -C≡CH, -C≡C(CH3), -C≡C(CH2CH3), -CH2C≡CH, -CH2C≡C(CH3), and -CH2C≡C(CH2CH3), etc.

[0090] As used herein, the term "independently selected from" refers to the groups mentioned being the same, different, or a mixture thereof, unless the context clearly indicates otherwise. Thus, in this definition, the expression "X 1 , X 2 , and X 3 are independently selected from the noble gases" includes, for example, X 1 , X 2 , and X 3When all are the same, X 1 X 2 and X 3 When all are different, X 1 and X 2 are the same but X 3 is different, and other similar permutations are included.

[0091] As used herein, the term "number average molecular weight" (M n ) refers to the ordinary arithmetic mean of the molecular weights of the individual molecules in a sample. This is defined as the total weight of all the molecules in the sample divided by the total number of molecules in the sample. Experimentally, M n is determined by analyzing a sample that has been fractionated into molecular weight fractions of species i having n n molecules of molecular weight M i n i by the formula M n = ΣM i n i / Σn n i . M

[0092] can be measured by various well-known methods such as gel permeation chromatography, spectroscopic end group analysis, and osmometry. Unless otherwise indicated, the molecular weights of the polymers shown herein are number average molecular weights.

[0093] As used herein, the term "organic group" refers to any carbon-containing functional group. Examples include oxygen-containing groups such as alkoxy, aryloxy, aralkyloxy, oxo (carbonyl) groups; carboxyl groups such as carboxylic acids, carboxylates, and carboxylic acid esters; sulfur-containing groups such as alkyl and aryl sulfide groups; and other heteroatom-containing groups. Non-limiting examples of organic groups include OR, OOR, OC(O)N(R)2, CN, CF3, OCF3, R, C(O), methylenedioxy, ethylenedioxy, N(R)2, SR, SOR, SO2R, SO2N(R)2, SO3R, C(O)R, C(O)C(O)R, C(O)CH2C(O)R, C(S)R, C(O)OR, OC(O)R, C(O)N(R)2, OC(O)N(R)2, C(S)N(R)2, (CH2) 0-2 N(R)C(O)R, (CH2) 0-2 N(R)N(R)2, N(R)N(R)C(O)R, N(R)N(R)C(O)OR, N(R)N(R)CON(R)2, N(R)SO2R, N(R)SO2N(R)2, N(R)C(O)OR, N(R)C(O)R, N(R)C(S)R, N(R)C(O)N(R)2, N(R)C(S)N(R)2, N(COR)COR, N(OR)R, C(=NH)N(R)2, C(O)N(OR)R, C(=NOR)R, and substituted or unsubstituted (C1-C 100 )hydrocarbyl, where R can be hydrogen (in examples containing other carbon atoms) or a carbon-based moiety, where the carbon-based moiety may or may not be substituted.

[0094] As used herein, the term "polymer" refers to a molecule having at least one repeating unit and may include copolymers. The polymers described herein may be terminated in any suitable manner. In some examples, the polymer is terminated by 0, 1, 2, or 3 groups independently selected from a suitable polymerization initiator, -H, -OH, or -O-, substituted or unsubstituted -NH-, and -S-, and a substituted or unsubstituted (C1-C20) hydrocarbyl (e.g., (C1-C10) alkyl or (C6-C20) aryl), poly(substituted or unsubstituted (C1-C20) hydrocarbyloxy), and poly(substituted or unsubstituted (C1-C20) hydrocarbylamino) interrupted by the group.

[0095] As used herein, the term "pore" refers to any size or shape of indentation, slit, or hole in a solid object. The pores may extend through or partially through the object. The pores can intersect with other pores.

[0096] As used herein, the term "radiation" refers to energetic particles that move through a medium or space. Examples of radiation are visible light, infrared light, microwaves, radio waves, very low low frequencies, extremely low low frequencies, thermal radiation (heat), and blackbody radiation.

[0097] As used herein, the term "resin" refers to any viscosity of polysiloxane material, such as a molecule containing at least one siloxane monomer bonded to three or four other siloxane monomers via Si-O-Si bonds. In one example, the polysiloxane material contains T units or Q units as defined herein.

[0098] As used herein, the term "room temperature" refers to a temperature of about 15°C to 28°C.

[0099] As used herein, the term "silica" refers to silicon dioxide (SiO2) of any particle size, shape, particle size distribution, shape distribution, and surface functionality, such as chemically treated silica. This can also refer to a polysiloxane containing a silicon-oxygen atomic network structure that at least partially includes a silicon-oxygen-silicon (silicon atom bonded to an oxygen atom bonded to a silicon atom) network structure, where the compound can be a polymer of any length or degree of branching. In various embodiments, the network structure can terminate with Si=O groups or Si-OH groups. The silica gel or matrix can contain 30%, 50%, 80%, 90%, 95%, 99%, 99.5%, 99.9% or any suitable percent composition (by weight) of polysiloxane.

[0100] As used herein, the term "silicate" refers to any silicon-containing compound that is an arbitrary salt of silicic acid, for example, in which a silicon atom has four bonds to oxygen and at least one of the oxygen atoms bonded to the silicon atom is ionic. The counterion to the oxygen ion can be any other suitable ion(s). The oxygen atom can be substituted with another silicon atom and can be in a polymer structure. One or more oxygen atoms can be double-bonded to the silicon atom, and thus, the silicate molecule can contain a silicon atom having two, three, or four oxygen atoms. Examples of silicates include aluminum silicate. Zeolite is an example of a material that can contain aluminum silicate. The silicate can be in the form of a salt or an ion.

[0101] As used herein, the term "solvent" refers to a liquid that can dissolve a solid, liquid, or gas. Non-limiting examples of solvents are silicone, organic compounds, water, alcohol, ionic liquids, and supercritical fluids.

[0102] As used herein, the term "substantially" refers to a majority or almost all, such as at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.

[0103] As used herein in connection with a molecule or organic group defined herein, the term "substituted" refers to a state in which one or more hydrogen atoms contained therein are replaced by one or more non-hydrogen atoms. As used herein, the term "functional group" or "substituent" refers to a group that is replaceable or has been replaced in a molecule or organic group. Examples of substituents or functional groups include, but are not limited to, halogen (e.g., F, Cl, Br, and I); oxygen atoms in groups such as carboxyl groups such as hydroxy group, alkoxy group, aryloxy group, aralkyloxy group, oxo (carbonyl) group, carboxylic acid, carboxylate, and carboxylic acid ester; sulfur atoms in groups such as thiol group, alkyl sulfide group, aryl sulfide group, sulfoxide group, sulfone group, sulfonyl group, and sulfonamide group; nitrogen atoms in groups such as amine, hydroxyamine, nitrile, nitro group, N-oxide, hydrazide, azide, and enamine; and various other groups of heteroatoms. Non-limiting examples of substituents that can be attached to a substituted carbon (or other) atom include F, Cl, Br, I, OR, OC(O)N(R)2, CN, NO, NO2, ONO2, azide, CF3, OCF3, R, O (oxo), S (thiono), C(O), S(O), methylenedioxy, ethylenedioxy, N(R)2, SR, SOR, SO2R, SO2N(R)2, SO3R, C(O)R, C(O)C(O)R, C(O)CH2C(O)R, C(S)R, C(O)OR, OC(O)R, C(O)N(R)2, OC(O)N(R)2, C(S)N(R)2, (CH2) 0-2 N(R)C(O)R, (CH2) 0-2N(R)N(R)2, N(R)N(R)C(O)R, N(R)N(R)C(O)OR, N(R)N(R)CON(R)2, N(R)SO2R, N(R)SO2N(R)2, N(R)C(O)OR, N(R)C(O)R, N(R)C(S)R, N(R)C(O)N(R)2, N(R)C(S)N(R)2, N(COR)COR, N(OR)R, C(=NH)N(R)2, C(O)N(OR)R, and C(=NOR)R, where R can be hydrogen or a carbon-based moiety. For example, R can be hydrogen, (C1-C 100 ) hydrocarbyl, alkyl, acyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl, or heteroarylalkyl; or two R groups attached to a nitrogen atom or adjacent nitrogen atoms can together with the nitrogen atom or nitrogen atoms form a heterocyclyl.

[0104] As used herein, the terms "thermoplastic polymer" or "thermoplastic" refer to polymers that have the property of converting to a fluid (flowable) state when heated and becoming rigid (non-flowable) when cooled. The term "thermoplastic polymer in a fluid state" as used herein refers to a polymer that is in a molten state or dissolved in an organic solvent.

[0105] As used herein, the term "molecular weight" refers to M w and is equal to ΣΜ i 2 n i / ΣΜ i n i where n i is the number of molecules of molecular weight M i . In various embodiments, the weight average molecular weight can be measured using light scattering, small angle neutron scattering, X-ray scattering, and sedimentation velocity.

[0106] Examples The various examples of the present disclosure can be better understood by reference to the following examples provided by way of illustration. The present disclosure is not limited to the examples shown herein.

[0107] Example 1. Sample Aluminosilicate Aerogel Two sets of sample aluminosilicate aerogels were produced according to the methods discussed herein and tested with comparative samples. All of these are summarized in Table 1 below: [Table 1]

[0108] Both Sample 1 and Sample 2 were prepared in the same manner as above. Sample 1 was prepared by the core / shell method in particular, and Sample 2 was prepared by the composite sol method. Both Sample 1 and Sample 2 were tested on a 1 mm glass reinforcement material. Both Sample 1 and Sample 2 were produced as a 2 mm layer on the reinforcement material unless otherwise noted.

[0109] Production of the core / shell sample. Sample 1, i.e., the aluminosilicate aerogel, was produced by the core / shell method. Here, the silica precursor was produced using tetraethyl orthosilicate (TEOS) (Dow Chemical). Sulfuric acid was used in the preparation of the sol to hydrolyze the silica precursor. Specifically, the TEOS sol was prepared with a water-to-TEOS ratio of 1.8, an acid content of 5 mM, and a silica solid content of 20%. The sols were mixed to first make the solution turbid. At this point, the aqueous phase and the TEOS / ethanol phase did not dissolve. The acid hydrolyzed the TEOS and released a large amount of ethanol. At this point, water showed miscibility with the rest of the solution. This coincided with the peak exotherm of the reaction.

[0110] At this point, boehmite (Sasol), an aluminum compound, was added at an Al:Si ratio of 3:1. If the addition was too early, the boehmite reacted with the acidic water and gelled immediately. Then, the solution was stirred. Guanidine, a gelling agent, was added. This solution was aged at 68 - 120 °C for 1 - 24 hours and then extracted with supercritical CO2.

[0111] Manufacture of composite sol sample. Aluminosilicate aerogel, which is Sample 2, was manufactured by the composite sol method. Here, the silica precursor was prepared using tetraethyl orthosilicate (TEOS). An acid was used in the preparation of the sol to hydrolyze the silica precursor. Specifically, the TEOS sol was prepared with a water-to-TEOS ratio of 1.8, an acid content of 5 mM, and a silica solid content of 20%. The sols were mixed to first make the solution turbid. At this point, the aqueous phase and the TEOS / ethanol phase did not dissolve. The acid hydrolyzed the TEOS and released a large amount of ethanol. At this point, water showed miscibility with the rest of the solution. This coincides with the peak exotherm of the reaction.

[0112] Here, boehmite, which is an aluminum compound, was added at the end of hydrolysis. Thereby, the molecular weight of TEOS could be increased, and a stronger aerogel network structure could be formed between the boehmite particles. After combining TEOS and boehmite, the sol was stirred to bond TEOS and boehmite together and change the boehmite surface just enough to withstand pH conversion and prevent gelation. Then, guanidine, which is a gelling agent, was added as described with reference to the core / shell method. The solution was aged and then extracted with supercritical CO2.

[0113] Comparative sample. The comparative sample (ATB1000) was an aerogel commercially available from Aspen Aerogel.

[0114] Sample 1, Sample 2, and the comparative sample were tested for various properties, such as thermal conductivity, density, flame impact, surface area, pore size, and thermal runaway, as summarized in Examples 2 to 6 below. As summarized in Example 7 below, additional samples were tested using reinforcing materials.

[0115] Example 2. Thermal conductivity The thermal conductivities of Sample 1 and Sample 2 were tested for both thicknesses of 1 mm and 2 mm, and the comparative sample (PyroThin® ATB1000) was tested similarly. To test the thermal conductivity, the revised ASTM C518 protocol was used. Here, a Wenesco hot plate was used with a maximum temperature of 815 °C and a digital temperature controller. The cold plate was a small piece of aluminum metal weighing 3.2 lb, exposed to ambient conditions and equilibrated with the environment.

[0116] Figure 1 shows the thermal conductivities (mW / m·K) of both Sample 1 and Sample 2. Both Sample 1 and Sample 2 produced similar thermal conductivities in the range of approximately 26.0 to approximately 26.5.

[0117] Figure 2 shows the thermal conductivities at various temperatures for both Sample 2 (composite sol) with thicknesses of 1 mm and 2 mm and the comparative sample (PyroThin® ATB1000). The low-temperature thermal conductivities of Sample 1 and Sample 2 were higher than that of the comparative sample (shown for thicknesses of 1 mm and 2 mm). The thermal conductivities of Sample 1 and Sample 2 were also good at higher temperatures. Overall, both samples functioned well in terms of thermal conductivity.

[0118] Example 3. Density For density, Sample 1 and Sample 2 were analyzed. The samples were measured for length, width, and height and then weighed. The bulk density was calculated. Here, both Sample 1 and Sample 2 were manufactured on a glass fiber reinforced structure for the density test. Figure 3 shows the densities (g / cc) of both Sample 1 and Sample 2. Both the sample 1 using the core / shell manufacturing method and the sample 2 using the composite sol manufacturing method produced similar density results. Both samples had densities in the range of approximately 0.24 g / cc to approximately 0.26 g / cc.

[0119] Example 4. Flame Impingement Sample 1 and Sample 2, each having a thickness of about 2 mm, were exposed to a flame at 1100 °C for 5 minutes to test for flame impact. Overall, each sample withstood the 5-minute flame impact but showed no signs of melting or densification. Overall, both samples functioned well in the flame impact test.

[0120] Figure 4 shows the low-temperature surface temperature (°C) of Sample 2 over 5 minutes (shown in seconds on the x-axis). A stable low-temperature surface temperature was reached at about 66 seconds after the start of the test, or just over 1 minute. The maximum low-temperature surface temperature was about 181 °C.

[0121] Example 5. Surface Area and Pore Size Sample 1 and Sample 2 were analyzed for surface area, pore size, and pore volume using Brunauer-Emmett-Teller (BET) surface area analysis. Here, Sample 1 and Sample 2 were used at a thickness of 2 mm with respect to the glass fiber reinforcement.

[0122] Figure 5 shows the BET surface area (m 2 / g), pore size (Å), and pore volume (cm 3 / g) of both Sample 1 and Sample 2. Sample 1 maintained a surface area of about 64.6 m 2 / g, while Sample 2 had a larger surface area of about 100.4 m 2 / g. In comparison, many silica-based aerogels such as the comparative sample have a specific surface area of about 500 - 1200 m 2 / g on average. Sample 1 had a pore volume of about 0.11 cm 3 / g and an average pore size of about 65.2 Å, while Sample 2 had a pore volume of about 0.16 cm 3 / g and an average pore size of about 62.0 Å.

[0123] Figures 6A and 6B show additional data for Sample 1. Specifically, Figure 6A shows the adsorption and desorption of Sample 1, and Figure 6B shows the pore size (Å) of Sample 1. Figures 7A and 7B show additional data for Sample 2. Specifically, Figure 7A shows the adsorption and desorption of Sample 2, and Figure 7B shows the pore size (Å) of Sample 2.

[0124] Example 6. Thermal Runaway Using a simulated thermal runaway procedure, the thermal runaways of Sample 1 and Sample 2 were tested. Both Sample 1 and Sample 2 were 2 mm thick on a glass-reinforced material for this simulation. In this simulation, a temperature of 1100 °C was applied to the high-temperature surface of the sample for 200 minutes.

[0125] During this simulation, neither Sample 1 nor Sample 2 developed cracks. In comparison, the performance of the comparative sample (ATB1000) was poor. The comparative sample had extensive cracks. The comparative sample had signs of melting and densification. In comparison, neither Sample 1 nor Sample 2 showed signs of melting or densification.

[0126] Figures 8A and 8B show the simulated thermal runaway temperatures (°C) at both the high-temperature and low-temperature surfaces of the sample versus time (minutes). Figure 8A shows Sample 1 (manufactured by the core / shell method), and Figure 8B shows Sample 2 (manufactured by the composite sol method). Both Sample 1 and Sample 2 had an average low-temperature surface temperature of approximately 600 to approximately 650 °C during the thermal runaway simulation.

[0127] Figure 9 shows the shrinkage (%) effect of the thermal runaway simulation for both Sample 1 and Sample 2. Here, the weight, average width, average length, and average thickness (TKS) were measured before and after the thermal runaway simulation. After the simulation, there was little shrinkage in either Sample 1 or Sample 2 across the entire material. In both Sample 1 and Sample 2, there was a small weight loss, which could be due to water or sizing on the reinforcing material.

[0128] Figure 10 shows the effect of thermal runaway on thermal conductivity for both Sample 1 and Sample 2. The average thermal conductivity (mW / m·K) is shown for both before and after the thermal runaway simulation. After the thermal runaway simulation, there was little change in the thermal conductivity for both Sample 1 and Sample 2.

[0129] Figure 11 shows the effect of thermal runaway on thickness and density for both Sample 1 and Sample 2. Here, in addition to the density (g / cc), the thickness (TKS) (mm) before and after the simulation is shown. The thickness of both Sample 1 and Sample 2 decreased slightly, and similarly, the density also decreased slightly.

[0130] Overall, both Sample 1 and Sample 2 were well retained during and after the simulated thermal runaway.

[0131] Example 7. Reinforcing Material Aluminosilicate aerogel samples were further manufactured and tested using various reinforcing materials. The above samples used only glass reinforcing materials, but other samples were tested here. These additional samples are summarized in Table 2 below:

Table 2

[0132] Casting process. During manufacturing, these samples used the above core / shell or composite sol methodology. However, boehmite, which is an aluminum compound, was added when the colloidal suspension was cast onto the reinforcing material. The remaining gelation steps and process treatment steps were the same as those described for the samples in Example 1 above.

[0133] In FIGS. 12 and 13, Sample 2 and Sample 2B are compared. Here, Sample 2 (using a glass reinforcing material) had a higher thermal conductivity than Sample 2B (using a melamine foam reinforcing material). The thickness of Sample 2B was thicker than that of Sample 2. In addition, the density of Sample 2B was lower than that of Sample 2.

[0134] FIG. 14 shows Test Samples 2 and 2B for simulated thermal runaway when exposed to a 1100° C. flame for 200 minutes or more. Here, a small heat generation peak due to melamine decomposition can be seen immediately after the start of the flame impact. However, Sample 2B has a low surface average temperature of about 600° C. In addition, Sample 2B containing a melamine reinforcing material underwent some shrinkage and became fragile.

[0135] Additional Examples The following exemplary examples are presented, and their numbers should not be construed as specifying levels of importance:

[0136] In some aspects, the techniques described herein relate to a method of making an aluminosilicate aerogel, the method comprising: containing a silica precursor in a solvent; hydrolyzing the silica precursor to produce colloidal silica; introducing an aluminum compound into the colloidal silica to produce a colloidal aluminosilicate suspension; converting the aluminosilicate suspension into an aluminosilicate gel composition; and forming an aluminosilicate aerogel by extracting a fluid.

[0137] In some aspects, the techniques described herein relate to a method in which the silica precursor is completely hydrolyzed before introducing the aluminum compound.

[0138] In some aspects, the techniques described herein relate to a method further comprising aging the aluminosilicate gel composition before forming the aluminosilicate aerogel.

[0139] In some embodiments, the technology described herein relates to a method in which aging the aluminosilicate gel composition includes heating the aluminosilicate gel composition at a temperature of 60°C to 120°C.

[0140] In some embodiments, the technology described herein relates to a method of aging an aluminosilicate gel composition over a time range of about 1 hour to about 24 hours.

[0141] In some embodiments, the technology described herein further relates to a method that includes dispersing a colloidal aluminosilicate suspension on a reinforcing material before converting the aluminosilicate suspension into an aluminosilicate gel composition.

[0142] In some embodiments, the technology described herein relates to a method of dispersing colloidal silica on a reinforcing material and simultaneously introducing an aluminum compound.

[0143] In some embodiments, the technology described herein relates to a method in which the reinforcing material is a fibrous material or a foamed material.

[0144] In some embodiments, the technology described herein relates to a method in which the silica precursors include tetraethyl orthosilicate (TEOS), trimethyl orthosilicate (TMOS), methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDES), trimethylmethoxysilane (TMS), dimethyldimethoxysilane (DMS), trimethylethoxysilane, ethyltriethoxysilane (ETES), diethyldiethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane (PhTES), hexamethyldisilazane, and hexaethyldisilazane, or combinations thereof.

[0145] In some embodiments, the technology described herein relates to a method in which the aluminum compound comprises boehmite, pseudoboehmite, alumina, aluminum trihydroxide, aluminum alkoxide, aluminum hydrocarboxylate species, or combinations thereof.

[0146] In some embodiments, the technology described herein relates to a method in which hydrolyzing a silica precursor comprises adding a sol initiator such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, oxalic acid, acetic acid, or combinations thereof.

[0147] In some embodiments, the technology described herein relates to a method in which converting an aluminosilicate suspension to an aluminosilicate gel composition comprises adding a gel initiator such as a metal hydroxide base or an amine base.

[0148] In some embodiments, the technology described herein relates to a method in which forming an aluminosilicate aerogel comprises extracting an excess fluid using a supercritical extraction process.

[0149] In some embodiments, the technology described herein relates to an aluminosilicate aerogel produced by this method.

[0150] In some embodiments, the technology described herein relates to a method of making an aluminosilicate aerogel, the method comprising mixing a silica precursor with a solvent to produce a precursor mixture; adding a sol initiator to the precursor mixture to produce colloidal silica; adding an aluminum compound to the colloidal silica to form a colloidal aluminosilicate suspension; adding a gel initiator to the colloidal aluminosilicate suspension to convert the colloidal aluminosilicate suspension to an aluminosilicate gel composition; and extracting a fluid from the aluminosilicate gel composition to form an aluminosilicate aerogel.

[0151] In some embodiments, the technology described herein relates to an aluminosilicate aerogel comprising an aluminum-containing shell surrounding a silica core, wherein the aerogel has a thermal conductivity of from about 25 to about 30 mW / m·K.

[0152] In some embodiments, the technology described herein relates to an aluminosilicate aerogel, wherein the aluminosilicate aerogel has a surface area of from about 60 to about 105 m2 / g.

[0153] In some embodiments, the technology described herein relates to an aluminosilicate aerogel, wherein the aluminosilicate aerogel has a pore size of from about 60 to about 70 Å.

[0154] In some embodiments, the technology described herein relates to an aluminosilicate aerogel, wherein the aluminosilicate aerogel has a pore volume of from about 0.10 to about 0.17 cm3 / g.

[0155] In some embodiments, the technology described herein relates to an aluminosilicate aerogel, wherein the aluminosilicate aerogel has a density of from about 0.200 to about 0.300 g / cc.

[0156] Throughout this specification, values expressed in range format are to be construed in a flexible manner so as to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range were explicitly recited. For example, a range of "from about 0.1% to about 5%" or "from about 0.1% to 5%" is to be construed to include not only from about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The notation "about X to Y" has the same meaning as "about X to about Y" unless otherwise indicated. Similarly, the description "about X, Y, or about Z" has the same meaning as "about X, about Y, or about Z" unless otherwise indicated.

[0157] As used herein, the terms "a", "an", or "the" are used to mean one or more, unless the context clearly indicates otherwise. The term "or" is used to mean a non-exclusive "or" unless otherwise indicated. The statement "at least one of A and B" has the same meaning as "A, B, or A and B". Further, it should be understood that any expressions or terms used herein that are not otherwise defined are for illustrative purposes only and not for purposes of limitation. The use of section headings is for the purpose of assisting in reading the specification only and is not to be construed as limiting; information related to a section heading may be presented inside or outside of that particular section. A comma may be used as a separator for digits groups or as a separator between the left or right side of a decimal point; for example, "0.000,1" is equivalent to "0.0001".

[0158] All publications, patents, and patent documents referred to herein are hereby incorporated by reference in their entirety as if each were individually incorporated by reference. In the event of any conflict in usage between this document and the incorporated references, the usage in the incorporated references should be considered supplementary to that of this document, and in the event of no conflict, the usage in this document shall prevail.

[0159] In the methods described herein, these acts can be performed in any order, without departing from the principles of the disclosure, unless the temporal or operational order is explicitly recited. Further, certain acts can be performed simultaneously, unless explicitly recited in the language of the claims to be performed individually. For example, the act recited in a claim of performing X and the act recited in a claim of performing Y can be performed simultaneously within one operation, and the resulting process will fall within the scope as set forth in the process recited in the claims.

[0160] The terms and expressions used in this specification are used as terms for explanation rather than for limitation, and the use of such terms and expressions is not intended to exclude any equivalents of the features shown and described or a part thereof, but it is recognized that various changes are possible within the scope of the embodiments of the present disclosure. Therefore, although the present disclosure is specifically disclosed by specific embodiments and any features, changes and modifications of the concepts disclosed herein may be made by those skilled in the art, and it is understood that such changes and modifications are considered to be within the scope of the embodiments of the present disclosure.

Claims

1. A method for producing an aluminosilicate aerogel, comprising: hydrolyzing a silica precursor to produce colloidal silica; introducing an aluminum compound into the colloidal silica to produce a colloidal aluminosilicate suspension; converting the colloidal aluminosilicate suspension into an aluminosilicate gel composition; forming the aluminosilicate aerogel by extracting a fluid.

2. The method according to claim 1, wherein the silica precursor is completely hydrolyzed before the introduction of the aluminum compound.

3. The method according to claim 1, further comprising aging the aluminosilicate gel composition before forming the aluminosilicate aerogel.

4. The method according to claim 3, wherein aging the aluminosilicate gel composition comprises heating the aluminosilicate gel composition at a temperature of 60°C to 120°C.

5. The method according to claim 3, wherein aging the aluminosilicate gel composition is carried out for a time ranging from about 1 hour to about 24 hours.

6. The method according to claim 1, further comprising dispersing the colloidal aluminosilicate suspension on a reinforcing material before converting the colloidal aluminosilicate suspension into an aluminosilicate gel composition.

7. The method according to claim 1, wherein the colloidal silica is dispersed on a reinforcing material and the aluminum compound is introduced simultaneously.

8. The method according to any one of claims 6 to 7, wherein the reinforcing material is a fibrous material or a foamed material.

9. The method according to claim 1, wherein the silica precursor comprises tetraethyl orthosilicate (TEOS), trimethyl orthosilicate (TMOS), methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDES), trimethylmethoxysilane (TMS), dimethyldimethoxysilane (DMS), trimethylethoxysilane, ethyltriethoxysilane (ETES), diethyldiethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane (PhTES), hexamethyldisilazane and hexaethyldisilazane, or a combination thereof.

10. The method according to claim 1, wherein the aluminum compound comprises boehmite, pseudo-boehmite, alumina, aluminum trihydroxide, aluminum alkoxide, aluminum hydrocarboxylic acid species, or a combination thereof.

11. The method according to claim 1, wherein hydrolyzing the silica precursor comprises adding a sol initiator comprising hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, oxalic acid, acetic acid, or a combination thereof.

12. The method according to claim 1, wherein converting the colloidal aluminosilicate suspension to an aluminosilicate gel composition comprises adding a gel initiator comprising a metal hydroxide base or an amine base.

13. The method according to claim 1, wherein forming the aluminosilicate aerogel comprises extracting excess fluid using a supercritical extraction process.

14. An aluminosilicate aerogel produced by the method according to claim 1.

15. A method for producing an aluminosilicate aerogel, comprising: mixing a silica precursor in a solvent to produce a precursor mixture; adding a sol initiator to the precursor mixture to produce colloidal silica; adding an aluminum compound to the colloidal silica to form a colloidal aluminosilicate suspension; adding a gel initiator to the colloidal aluminosilicate suspension to convert the colloidal aluminosilicate suspension to an aluminosilicate gel composition; and extracting fluid from the aluminosilicate gel composition to form the aluminosilicate aerogel.

16. An aerogel comprising an aluminosilicate comprising an aluminum-containing shell surrounding a silica core, the aerogel having a thermal conductivity of about 20 to about 30 mW / m·K.

17. The aluminosilicate aerogel according to claim 16, wherein the aluminosilicate aerogel has a surface area of about 60 to about 105 m ２ / g.

18. The aluminosilicate aerogel according to claim 16, wherein the aluminosilicate aerogel has an average pore size of about 60 to about 70 Å.

19. The aluminosilicate aerogel having a pore volume of about 0.10 to about 0.17 cm ３ / g, the aluminosilicate aerogel according to claim 16.

20. The aluminosilicate aerogel according to claim 16, wherein the aluminosilicate aerogel has a density of about 0.200 to about 0.300 g / cc.

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