A ceramifiable composite material, its preparation method and use

Abstract

A ceramicized composite material, its preparation method, and its application, comprising, by weight: 100 parts of silicone rubber matrix; 50-120 parts of ceramic-forming filler system; 10-40 parts of active fire extinguishing microcapsules; 5-20 parts of sacrificial template agent; and 2-10 parts of synergistic additives. The ceramic-forming filler system, by weight, comprises: 30-60 parts of synthetic fluorophlogopite powder; 15-40 parts of low-melting-point glass powder; and 5-20 parts of reinforcing skeleton filler. The core material of the active fire extinguishing microcapsules is perfluorohexanone; the wall material of the active fire extinguishing microcapsules has a double-layer structure, with an inner layer of melamine resin and an outer layer of polyurea or silica grafted with vinyl groups. The sacrificial template agent is a core-shell structured thermoplastic expandable microsphere, with a core material of liquid alkane and a shell material of a copolymer of vinylidene chloride, acrylonitrile, and methyl methacrylate; the expansion temperature of the sacrificial template agent is 180°C-220°C, and its pyrolysis temperature is 300°C-400°C. This invention has the advantages of active flame suppression, ultra-low thermal conductivity, and robust structure.

Description

Technical Field

[0001] This invention relates to the field of thermal management and safety protection materials for new energy batteries, specifically to a ceramicized composite material, its preparation method, and its application. Background Technology

[0002] With the pursuit of longer driving range in the new energy industry, the energy density of lithium-ion batteries has exceeded 300Wh / kg (such as the high-nickel NCM811 system). However, high energy density means higher chemical instability. When the battery is subjected to mechanical abuse (needle penetration, compression), electrical abuse (overcharging, short circuit), or thermal abuse, the internal separator melts, causing a short circuit between the positive and negative electrodes, which triggers a series of irreversible exothermic reactions: 1. SEI film decomposition (~90°C-120°C): The solid electrolyte interfacial film on the negative electrode surface decomposes, releasing heat.

[0003] 2. Reaction of negative electrode with electrolyte (>120°C): The exposed lithium-intercalated negative electrode undergoes a reduction reaction with the electrolyte, producing gas and releasing heat.

[0004] 3. Diaphragm melting and large-scale short circuit (~130°C-170°C): The polyolefin diaphragm closes its pores and eventually melts, resulting in a large-area internal short circuit and a sharp rise in temperature.

[0005] 4. Positive electrode decomposition (>180°C): The positive electrode material releases lattice oxygen, which undergoes a violent oxidation reaction with the electrolyte. At this time, the internal temperature of the battery can soar to 800°C or even 1000°C or more within seconds, accompanied by a high-temperature and high-pressure jet containing hydrogen, methane, carbon monoxide and electrolyte vapor.

[0006] If this type of single-cell thermal runaway caused by an irreversible exothermic reaction cannot be effectively contained, it will rapidly heat adjacent cells through heat conduction, heat convection, and heat radiation, leading to a domino effect of heat propagation and potentially causing a catastrophic accident. Therefore, it is an industry consensus to install protective materials between cells that can block heat flow and suppress fire.

[0007] To curb this type of single-cell thermal runaway, the industry typically incorporates thermal insulation materials between battery cells. Currently, the mainstream cell insulation materials in the industry mainly include aerogel felt, mica sheets, and traditional ceramicized silicone rubber. However, they all have significant drawbacks when dealing with extremely high energy density batteries, and their respective shortcomings are as follows: 1. Mechanical and Cost Challenges of Aerogel Materials: Aerogels are inherently fragile with extremely low mechanical strength and are prone to dusting, which not only contaminates the internal electrical environment of the battery pack but also causes thermal insulation performance to degrade over time. Although the strength can be enhanced by composite fibers (such as pre-oxidized fibers and glass fibers), the aerogel skeleton will experience severe structural collapse and sintering under high-temperature impacts above 1000°C, leading to a surge in thermal conductivity. Furthermore, its high manufacturing cost also limits its large-scale application.

[0008] 2. Limitations of Mica Modules in Thermal Conductivity and Density: Mica has a layered, dense structure with a thermal conductivity typically between 0.15 and 0.30 W / m·K, significantly higher than that of aerogel. With the design trend towards increasingly compact cell gaps (<2 mm), the thermal resistance of the mica layer is often insufficient to prevent thermal runaway propagation. Furthermore, mica has a high density (>2.0 g / cm³). 3 This is detrimental to the lightweight design of battery packs. At high temperatures, the organic binder decomposes, causing the mica sheets to easily crumble and lose their structural integrity.

[0009] 3. The Performance Paradox of Traditional Ceramicized Silicone Rubber: To ensure the strength after ceramicization, a large amount of inorganic filler (such as mica powder, glass powder, wollastonite, etc.) is usually added to the formulation, which leads to a reduction in the content of the matrix resin. High filler content makes it difficult to reduce the thermal conductivity in the raw rubber state (typically >0.20 W / m·K), failing to meet the thermal insulation requirements under normal operating conditions. The pore-forming process in the traditional ceramicization process mainly relies on the oxidative decomposition of organosilicon side groups (methyl, vinyl) to generate gas. This foaming process is random and disordered, often forming interconnected "open-cell" structures. High-temperature, high-pressure gas flows can easily penetrate these open cells, leading to significant thermal convection effects and even "fire spurts."

[0010] Moreover, aerogel felt, mica board, and traditional ceramicized silicone rubber are all "passive defense" systems, which can only delay heat transfer through physical barriers and cannot actively reduce the temperature of the source of thermal runaway or inhibit the rate of chemical reaction. Faced with the safety challenges brought about by the continuous increase in energy density, relying solely on passive insulation has reached its physical limits.

[0011] Therefore, the industry urgently needs a new type of material that can "actively sense and intelligently respond," and this new material should have the following characteristics: 1. Active fire suppression: In the early stages of thermal runaway, it can release fire extinguishing agents, physically cool down and chemically capture free radicals, delaying or blocking the generation of fire.

[0012] 2. Ultra-low thermal conductivity: At high temperatures, it can form a closed-cell structure similar to aerogel in situ, reducing the thermal conductivity to below 0.05 W / m·K.

[0013] 3. Robust structure: Under extremely high temperatures, it can form a hard ceramic "armor" to resist the erosion of the jet stream. Summary of the Invention

[0014] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a ceramicized composite material, its preparation method and application, so as to solve the above-mentioned technical problems.

[0015] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a ceramicized composite material, comprising, by weight: 100 parts of silicone rubber matrix; 50-120 parts of ceramic filler system; 10-40 portions of active fire extinguishing microcapsules; Sacrificial template agent 5-20 parts; 2-10 parts of synergistic adjuvant.

[0016] Furthermore, the silicone rubber matrix is ​​preferably addition-type liquid silicone rubber or high-temperature vulcanized silicone rubber.

[0017] Furthermore, the ceramic filler system comprises, by weight, the following: 30-60 parts of synthetic fluorinated phlogopite powder with a particle size D50 of 10-50 μm; 15-40 parts of low melting point glass powder, with a softening point of 450°C-550°C; The reinforcing skeleton filler consists of 5-20 parts, selected from one or more of wollastonite or chopped high-silica fibers.

[0018] Furthermore, the core material of the active fire extinguishing microcapsule is perfluorohexanone; the wall material of the active fire extinguishing microcapsule has a double-layer structure, with the inner layer being melamine resin and the outer layer being a polyurea layer or a silicon dioxide layer with vinyl groups grafted on its surface.

[0019] Furthermore, the sacrificial template agent is a core-shell structured thermoplastic expandable microsphere, with its core material being liquid alkane and its shell material being a copolymer of vinylidene chloride, acrylonitrile, and methyl methacrylate; the expansion temperature of the sacrificial template agent is 180°C-220°C, and its pyrolysis temperature is 300°C-400°C.

[0020] Furthermore, synergistic agents include: The catalyst and the structure control agent have a molar mass ratio of 20:1. Platinum catalyst is preferred, and hydroxyl silicone oil is preferred as the structure control agent.

[0021] Secondly, the present invention provides a method for preparing a ceramicized composite material, comprising the following steps: S1. Mix 50-120 parts of ceramic filler system with 100 parts of silicone rubber matrix at 120°C-140°C for 2-2.5 hours, remove low molecular weight volatiles by vacuuming, and cool to room temperature to obtain masterbatch. S2. Cool the masterbatch to below 40°C, add 10-40 parts of active fire extinguishing microcapsules, 5-20 parts of sacrificial template agent and 2-10 parts of synergistic agent at a speed of less than 60 RPM, and degas under vacuum to obtain slurry; S3. Calender the slurry and perform graded vulcanization and shaping under conditions lower than the initial expansion temperature of the sacrificial template agent.

[0022] Furthermore, in step S2, before adding the active fire extinguishing microcapsules, the active fire extinguishing microcapsules are pretreated. The pretreatment process is as follows: 50-100 parts of the active fire extinguishing microcapsules are dispersed in an ethanol aqueous solution, 1-2 parts of vinyltrimethoxysilane are added, and the mixture is stirred and hydrolyzed at 50°C-55°C for 2-2.5 hours, and then filtered and dried.

[0023] Furthermore, step S3, graded vulcanization and shaping, includes: Low-temperature setting: The material is set under pressure at 90°C for 20 minutes using a flat vulcanizing machine. Post-curing involves placing the demolded product in hot air at 110°C for 2 hours.

[0024] Thirdly, the present invention provides an application of a ceramicized composite material, which is used to produce a battery thermal runaway protection sheet. The battery thermal runaway protection sheet is disposed between adjacent cells of a battery module or attached to the inner side of the top cover of a battery pack to block heat transmission between cells.

[0025] Compared with the prior art, the beneficial effects of the present invention are: The ceramicized composite material of this invention is a high-performance functional composite material used to suppress the propagation of thermal runaway in electrochemical energy storage devices (such as lithium-ion batteries and supercapacitors). At room temperature, this material exhibits a certain degree of flexibility and insulation in an organosilicon elastomer, adaptable to the assembly tolerances and breathing effects of battery modules. In the initial stage of thermal runaway (150°C-200°C), the material can release chemical inhibitors through microcapsule rupture, actively intervening in the combustion chain reaction. In the high-temperature stage of thermal runaway (>400°C), the material constructs a directional closed-cell structure in situ through a sacrificial template mechanism, achieving a step-wise decrease in thermal conductivity, and ultimately transforming into a rigid ceramic shell, forming a physical barrier capable of resisting high-pressure airflow and continuous high-temperature ablation. This invention breaks away from the traditional design thinking of "uniform composition and single function" for thermal insulation materials, proposing a material design concept of "time-temperature dual-dimensional response." By introducing two types of functional microspheres with different thermal response thresholds—active fire-extinguishing microcapsules and sacrificial template microspheres—into a ceramicized silicone rubber matrix, the material achieves graded response and functional evolution during the thermal runaway process.

[0026] T1 stage (150-200°C): Active fire extinguishing microcapsules rupture, releasing perfluorohexanone, which absorbs heat, cools the temperature, and inhibits the combustion chain reaction (active defense).

[0027] T2 stage (>400°C): The sacrificial template microspheres disappear after expansion and pyrolysis, leaving in-situ oriented closed-cell cavities, achieving a step decrease in thermal conductivity (passive defense enhancement).

[0028] T3 stage (>800°C): The matrix undergoes a ceramic phase transformation, liquid glass powder seals micro-defects, and mullite crystal phase reconstructs the framework to form the ultimate protective layer. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1 On one hand, this embodiment provides a ceramicized composite material, the components of which (by weight) include: 1. Matrix resin (100 parts): preferably addition-type liquid silicone rubber (LSR) or high-temperature vulcanized silicone rubber (HTV). Since this invention relates to the construction of precise microstructures, LSR is preferred because its lower viscosity and good flowability are more conducive to the dispersion and shaping of functional microspheres.

[0031] 2. Ceramic filler system (50-120 parts): Ceramic matrix: Synthetic fluorophlogopite powder (30-60 parts), particle size D50=10-50μm. Synthetic mica has higher temperature resistance (>1100°C) and lower impurity content than natural mica.

[0032] Flux: Low melting point glass powder (15-40 parts), softening point between 450°C and 550°C. Borosilicate or phosphate glass powder is preferred, used to form a liquid phase at high temperatures, bind fillers, and seal pores.

[0033] Reinforcing skeleton: Wollastonite with a high aspect ratio or short-cut high silica fiber (5-20 parts) is used to improve the mechanical strength of the ceramic body and prevent cracking.

[0034] 3. Active fire extinguishing microcapsules (10-40 parts): Core material: Perfluorohexanone (FK-5-1-12, C6F12O). Its boiling point is 49.2°C, and it has excellent extinguishing concentration (4.5-6%) and extremely high safety (GWP=1, ODP=0).

[0035] Wall material: Modified melamine-formaldehyde resin or polyurea. The wall material needs to be specially designed to control its cracking temperature between 150°C and 200°C, and to have sufficient strength to withstand the shear force of the silicone rubber compound.

[0036] Modification: Vinyl or epoxy groups are grafted onto the surface of the wall material to improve compatibility with the silicone rubber matrix and prevent interfacial delamination.

[0037] 4. Sacrificial template agent (5-20 parts): Type: Thermoplastic expandable microbeads, such as the Expancel series.

[0038] Structure: Core-shell structure, with the core being a liquid alkane (such as isopentane or isooctane) and the shell being a thermoplastic copolymer (such as vinylidene chloride-acrylonitrile-methyl methacrylate).

[0039] Thermal properties: The initial expansion temperature needs to be higher than the vulcanization temperature of silicone rubber (e.g., >130°C), the maximum expansion temperature is between 180°C and 220°C, and the pyrolysis temperature is between 300°C and 400°C.

[0040] 5. Synergistic adjuvant (2-10 parts): Catalyst: Platinum catalyst (used in addition-type silica gel). It must be used in conjunction with an inhibitor (such as acetylenecyclohexanol) to prevent catalyst poisoning caused by the microcapsule wall material (such as those containing nitrogen or sulfur).

[0041] Structure control agent: hydroxyl silicone oil, used to improve filler dispersion.

[0042] On the other hand, this embodiment provides a method for preparing a ceramicized composite material, the process flow of which is as follows: Step 1: Pretreatment of functional microspheres To prevent the perfluorohexanone microcapsules from rupturing during subsequent mixing and to address their compatibility with the organosilicon matrix, a secondary coating is required.

[0043] 100g of FK-5-1-12 microcapsules (with melamine resin as the wall material) were dispersed in an ethanol-water solution, and 2g of vinyltrimethoxysilane (VTMS) was added. The mixture was stirred at 50°C for 2 hours to hydrolyze and condense, and then filtered and dried. This step introduces vinyl groups onto the surface of the microcapsules, enabling them to participate in the vulcanization and crosslinking of silicone rubber, thus becoming reinforcing points rather than defect points.

[0044] Step 2: Preparation of ceramicized masterbatch Add 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 10,000 mPa·s), 30 parts of fumed silica (treated with HMDS), 40 parts of synthetic fluorophlogopite powder, 20 parts of low-melting-point borosilicate glass powder (softening point 480°C), and 5 parts of chopped high-silica fibers to a vacuum kneader.

[0045] The mixture is high-shear mixed at 120°C for 2 hours, then vacuum-dried to remove low-molecular-weight volatiles, and cooled to room temperature to obtain the base masterbatch.

[0046] Step 3: Mild blending and activity protection Transfer the base masterbatch to a planetary mixer (with water cooling, control the material temperature <40°C).

[0047] Add 30 parts of pretreated FK-5-1-12 microcapsules and 10 parts of Expansionl920DU80 microbeads (T_start=130°C).

[0048] Add 2 parts of hydrogen-containing silicone oil (crosslinking agent) and 0.1 parts of platinum catalyst (containing acetylene cyclohexanol inhibitor).

[0049] Key process: Low-speed, low-shear stirring (<60 rpm) is used to prevent damage to microcapsules and microbeads. Vacuum degassing is performed for 30 minutes.

[0050] Step 4: Oriented molding and graded vulcanization The slurry is calendered into 1.5 mm thick sheets using a precision calender. The shear force during the calendering process induces the flaky mica and spherical microspheres to align in the planar direction.

[0051] Graded vulcanization process: Low-temperature setting: 90°C × 20 min. This temperature is much lower than the initial expansion temperature of the microspheres (130°C) and the rupture temperature of the microcapsules (160°C), ensuring that the matrix is ​​initially cross-linked and set, locking the position of the microspheres, and not triggering their activity.

[0052] Post-curing: 110°C × 2 hours. This further increases cross-linking density and eliminates internal stress. The maximum temperature must be strictly controlled to not exceed 120°C.

[0053] The core mechanism of the ceramicized composite material in this embodiment is: A. Sacrificial template mechanism: the leap from 0.12 to 0.05 W / m·K This is the key to achieving ultra-low thermal conductivity in this invention. Traditional ceramicized silicone rubber's pores primarily originate from the decomposition of organic matter, resulting in low porosity and high connectivity. This invention utilizes the "expansion-curing-sacrifice" full lifecycle characteristics of microspheres to precisely control the pore structure.

[0054] Microscopic processes: Pre-embedding stage (room temperature): Microspheres are uniformly dispersed in the silica matrix at their original particle size (10-30μm). At this stage, the material is dense and has a high thermal conductivity (~0.2W / m·K), which is beneficial for heat dissipation and temperature uniformity during normal battery operation.

[0055] Expansion stage (130°C-200°C): When thermal runaway occurs and the temperature rises, the alkanes inside the microspheres vaporize, expanding in volume by 40-80 times. At this time, the silicone rubber matrix provides elastic constraints, and the microspheres compress the surrounding ceramic fillers, forming a dense stacked wall.

[0056] Shaping stage (200°C-400°C): The microspheres expand to their limit, and the shell hardens. At this time, the material volume increases significantly, increasing thermal resistance.

[0057] Sacrificial pore-forming stage (>400°C): As the temperature continues to rise, the polymer shell of the microspheres undergoes pyrolysis and carbonization, eventually becoming completely vaporized (“sacrificial”). Crucially, at this stage, the flux (glass powder) in the matrix has not yet fully flowed and sealed the pores, or has only just begun to soften. The space occupied by the microspheres leaves spherical, unconnected closed-cell cavities in situ.

[0058] Ceramic keyhole stage (>600°C): The glass powder is completely melted, impregnating the mica and fibers, "freezing" the above-mentioned closed-cell structure in a hard ceramic matrix.

[0059] Mechanism of thermal conductivity reduction: Gas insulation: The thermal conductivity of still air is only 0.026 W / m·K. The closed-cell structure effectively traps the air, preventing heat transfer through gas convection at high temperatures.

[0060] Phonon scattering: In the thermal conductivity of ceramic solids, phonons are the main heat carriers. The large number of micron-sized closed-pore interfaces generated in situ greatly increases the phonon scattering cross section and significantly reduces the thermal conductivity of the solid phase.

[0061] Twisting path: The directional arrangement of closed pores forces heat flow to bypass the cavity, significantly lengthening the heat conduction path.

[0062] B. Active chemical fire suppression mechanism: second-level response Physical cooling: The latent heat of vaporization of perfluorohexanone is 88 kJ / kg. Although the value is not large, in a small, enclosed space, its instantaneous vaporization endothermic energy can significantly reduce the local temperature and delay the diaphragm melt-through time.

[0063] Free radical scavenging: The essence of combustion reaction is a free radical chain reaction (H· + O2 → ·OH + O·). The fluorine-containing free radicals (CF3·) generated by the decomposition of perfluorohexanone at high temperature can rapidly combine with H· and ·OH to generate stable HF or CF3H, thereby breaking the combustion chain.

[0064] Example of a reaction: C6F12O→C3F·+C2F5CO·; CF3·+H·→CF3H.

[0065] Synergistic effect: During the escape process, the gas released from the microcapsules utilizes the initial pores left by the expanded microspheres as channels to form a slightly positive pressure airflow from the inside out, further blocking the intrusion of external hot airflow. This "airflow backflush" effect is not present in single materials.

[0066] The technical effects of ceramic composite materials: the logic of offense and defense conversion The ceramicized composite material in this embodiment represents an evolution from "passive defense" to "intelligent offense and defense": Comparative Example 1: This comparative example is a conventional ceramicized silicone rubber prepared using existing technology. The preparation process is well known to those skilled in the art, therefore, the preparation process will not be described in detail.

[0067] Comparative Example 2: The preparation method used in this comparative example differs from that provided in Example 1 in that Expansionl920DU80 microspheres are not added in step three. Consequently, the resulting ceramicized composite material does not contain a sacrificial template agent.

[0068] Comparative Example 3: The preparation method used in this comparative example differs from that provided in Example 1 in that pretreated FK-5-1-12 microcapsules are not added in step three. Consequently, the resulting ceramicized composite material does not contain active fire-extinguishing microcapsules.

[0069] Performance tests were conducted on Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, and the results are shown in the table below: Data Analysis: Achieving ultra-low thermal conductivity: Example 1 achieved a thermal conductivity of 0.042 W / m·K at 600°C, significantly better than Comparative Example 1 (0.15). This directly verifies the effectiveness of the "sacrificial template mechanism." Compared to Comparative Example 3, although both added microbeads, Example 1 achieved a lower thermal conductivity due to the synergistic insulating effect (cushion effect) of the microcapsule gas.

[0070] Balancing strength and thermal insulation: Comparative Example 3, with the addition of microspheres, exhibits good thermal insulation but extremely low strength after ablation (2.1 MPa), making it prone to pulverization under airflow impact. Example 1, through the synergistic effect of the microcapsule shell and the ceramic filler (the residual carbon in the microcapsule shell is also part of the skeleton), maintains a high ceramic strength (5.2 MPa), solving the problem of "porousness leading to brittleness".

[0071] A qualitative leap in blocking time: Example 1 achieved a blocking time of over 60 minutes, far exceeding the national standard requirement of 5 minutes. This is the result of the combined effect of "active fire extinguishing" weakening the fire source energy and "passive heat insulation" blocking the transfer of residual heat. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A ceramicized composite material, characterized in that, Included by weight: 100 parts of silicone rubber matrix; 50-120 parts of ceramic filler system; 10-40 portions of active fire extinguishing microcapsules; Sacrificial template agent 5-20 parts; 2-10 parts of synergistic adjuvant.

2. The ceramicized composite material according to claim 1, characterized in that, The preferred silicone rubber matrix is ​​addition-type liquid silicone rubber or high-temperature vulcanized silicone rubber.

3. The ceramicized composite material according to claim 1, characterized in that, The ceramic filler system includes, by weight, the following components: 30-60 parts of synthetic fluorinated phlogopite powder with a particle size D50 of 10-50 μm were obtained. 15-40 parts of low melting point glass powder, with a softening point of 450°C-550°C; The reinforcing skeleton filler consists of 5-20 parts, selected from one or more of wollastonite or chopped high-silica fibers.

4. The ceramicized composite material according to claim 1, characterized in that, The core material of the active fire extinguishing microcapsule is perfluorohexanone; the wall material of the active fire extinguishing microcapsule has a double-layer structure, with the inner layer being melamine resin and the outer layer being a polyurea layer or a silicon dioxide layer with vinyl groups grafted on its surface.

5. The ceramicized composite material according to claim 1, characterized in that, The sacrificial template agent is a core-shell structured thermoplastic expandable microsphere. Its core material is liquid alkane, and its shell material is a copolymer of vinylidene chloride, acrylonitrile, and methyl methacrylate. The expansion temperature of the sacrificial template agent is 180°C-220°C, and its pyrolysis temperature is 300°C-400°C.

6. The ceramicized composite material according to claim 1, characterized in that, Synergistic adjuvants include: The catalyst and the structure control agent have a molar mass ratio of 20:

1. Platinum catalyst is preferred, and hydroxyl silicone oil is preferred as the structure control agent.

7. The method for preparing the ceramicized composite material according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Mix 50-120 parts of ceramic filler system with 100 parts of silicone rubber matrix at 120°C-140°C for 2-2.5 hours, remove low molecular weight volatiles by vacuuming, and cool to room temperature to obtain masterbatch. S2. Cool the masterbatch to below 40°C, add 10-40 parts of active fire extinguishing microcapsules, 5-20 parts of sacrificial template agent and 2-10 parts of synergistic agent at a speed of less than 60 RPM, and degas under vacuum to obtain slurry; S3. Calender the slurry and perform graded vulcanization and shaping under conditions lower than the initial expansion temperature of the sacrificial template agent.

8. The preparation method according to claim 7, characterized in that, In step S2, before adding the active fire extinguishing microcapsules, the active fire extinguishing microcapsules are pretreated. The pretreatment process is as follows: 50-100 parts of the active fire extinguishing microcapsules are dispersed in an ethanol aqueous solution, 1-2 parts of vinyltrimethoxysilane are added, and the mixture is stirred and hydrolyzed at 50°C-55°C for 2-2.5 hours, and then filtered and dried.

9. The preparation method according to claim 7, characterized in that, Step S3, graded vulcanization and shaping, includes: Low-temperature setting: The material is set under pressure at 90°C for 20 minutes using a flat vulcanizing machine. Post-curing involves placing the demolded product in hot air at 110°C for 2 hours.

10. The application of the ceramicized composite material according to any one of claims 1-6, characterized in that: Ceramicized composite materials are used to produce battery thermal runaway protection sheets. These sheets are placed between adjacent cells in a battery module or attached to the inside of the top cover of a battery pack to block heat transfer between cells.

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