Ceramic heat-proof and heat-insulating coating material, preparation and application thereof

Abstract

The application relates to the technical field of special functional coating, in particular to a ceramic heat-proof coating and a preparation and application thereof. The ceramic heat-proof coating comprises an inner layer heat-proof fire-resistant coating and an outer layer sealing fire-resistant coating; the heat-proof fire-resistant coating comprises an A component and a B component; the A component comprises first semi-crystal multi-element fire-resistant ceramic powder, first silicon-based precursor high polymer, first crosslinking agent and crosslinking inhibitor; the B component comprises heat-proof filler, reinforcing agent, core-shell flame-retardant filler, coupling agent, dispersant and solvent; the sealing fire-resistant coating comprises second semi-crystal multi-element fire-resistant ceramic powder, second silicon-based precursor high polymer and second crosslinking agent. The coating prepared by using the material can significantly improve the safety protection capability of a lithium battery under extreme heat conditions.

Description

Technical Field

[0001] This invention relates to the field of special functional coatings technology, and in particular to a ceramic heat-insulating coating and its preparation and application. Background Technology

[0002] With the rapid development of electric vehicles and energy storage technologies, high-energy-density lithium batteries have become the core of energy storage and power. However, their thermal safety management is facing increasingly severe challenges. Under abnormal conditions such as overcharging, short circuits, and mechanical damage, thermal runaway may occur inside the battery, with the temperature rapidly rising to hundreds or even over 1,000 degrees Celsius in a very short time, accompanied by the release of large amounts of flammable gases and heat, which may ultimately lead to serious safety accidents such as fires and explosions. Therefore, developing an efficient and reliable thermal protection system has become a key link in improving the safety of lithium batteries. Among them, applying a protective coating material with high-efficiency heat insulation, ultra-high temperature resistance, excellent corrosion resistance, and good adhesion to the surface of the battery casing or key heat transfer paths is considered an effective means to suppress the spread of thermal runaway and improve the system safety level.

[0003] Existing thermal insulation coating technologies often struggle to achieve a balanced performance across multiple key aspects. Specifically, an ideal battery thermal protection coating needs to meet the following requirements simultaneously: First, it must possess ultra-high temperature resistance, meaning it can maintain structural integrity and functional stability under extreme instantaneous thermal shocks exceeding 1800°C, without melting or decomposing, thus preventing the transfer of high temperatures to surrounding battery modules or other parts of the system. Second, the coating must have extremely low thermal conductivity (typically below 0.2 W / m·K), thereby constructing an efficient thermal barrier at the material level and significantly delaying heat diffusion. Third, since lithium batteries typically use organic carbonate electrolytes, which have certain chemical activity and permeability, the coating must be able to resist long-term corrosion, swelling, or dissolution by the electrolyte, maintaining performance without degradation. Furthermore, the coating must have excellent bonding strength with common battery casing materials (such as aluminum alloys and stainless steel) to prevent peeling under vibration, impact, or thermal cycling. Finally, from an engineering application perspective, coating materials should also have good workability. For example, they should be able to form a uniform and dense film through processes such as spraying, brushing, and dipping, and have reasonable curing temperature, time, and cost to meet the needs of large-scale production.

[0004] However, existing material systems often have trade-offs. For example, while some ceramic-based coatings offer high temperature resistance and good thermal insulation, they are brittle and prone to cracking under thermal shock or mechanical stress. Furthermore, the mismatch in thermal expansion coefficients with the metal casing can lead to insufficient adhesion. Some polymer-based composite coatings, while easy to apply and with good adhesion, typically have low temperature limits (generally below 500°C), making them unable to withstand the high-temperature shocks of thermal runaway. On the other hand, resistance to electrolyte corrosion requires extremely dense and chemically inert coating materials, which may conflict with the porous or layered structure design required for low thermal conductivity. Simultaneously, achieving resistance exceeding 1800°C often necessitates the introduction of high-melting-point components or special structures, which can increase process complexity and cost.

[0005] Therefore, it is crucial to develop a protective coating material that can effectively insulate against heat, withstand high temperatures, resist lithium-ion electrolyte corrosion, and bond firmly to the battery casing. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a ceramic heat-insulating coating and its preparation and application. The coating obtained using this ceramic heat-insulating coating has a double-layer composite structure (comprising a heat-insulating underlayer and a dense sealing outer layer), capable of withstanding high temperatures up to 1800℃. It also possesses excellent high-temperature resistance, heat insulation, flame retardancy, corrosion resistance, and high-velocity impact resistance, significantly improving the thermal safety protection level of lithium batteries (especially in applications in extreme environments).

[0007] The objective of this invention can be achieved through the following technical solutions: The first objective of this invention is to provide a ceramic heat-insulating coating, characterized in that it comprises an inner heat-insulating and fire-resistant coating and an outer sealing and fire-resistant coating, which are used independently and in combination; wherein the heat-insulating and fire-resistant coating comprises component A and component B in a mass ratio of 1~2:1~3; Component A comprises the following components in parts by weight: 10-20 parts of the first semi-crystalline multi-component refractory ceramic powder, 20-40 parts of the first silicon-based precursor polymer, 1-2 parts of the first crosslinking agent, and 0.5-3 parts of the crosslinking inhibitor. Component B comprises the following components in parts by weight: 5-15 parts of thermal insulation filler, 0.5-2.0 parts of reinforcing agent, 2.5-10 parts of core-shell flame retardant filler, 0.4-1 parts of coupling agent, 0.1-0.8 parts of dispersant, and 10-20 parts of solvent. The sealing refractory coating comprises 5-10 parts of a second semi-crystalline multi-element refractory ceramic powder, 30-40 parts of a second silicon-based precursor polymer, and 1-2 parts of a second crosslinking agent.

[0008] In one embodiment of the present invention, the first semi-crystalline multi-component refractory ceramic powder is the semi-crystalline multi-component ceramic powder of patent CN120117894A. The first silicon-based precursor polymer is selected from one or more of polycarbomethylsilane, polyether-modified polysiloxane, polyimide powder, poly(1,1-dimethylsilazane), 108 silicone rubber, or 109 silicone rubber. The first crosslinking agent is selected from one or more of methyl orthosilicate, ethyl orthosilicate, or trimethoxysilane; The cross-linking inhibitor is selected from one or more of 3-methyl-1-butyn-3-ol, trimethyl-1-pentyn-3-ol, or 3,5-dimethyl-1-hexyn-3-ol.

[0009] In one embodiment of the present invention, the heat insulation filler is high-entropy ceramic nanocrystal powder of patent CN114516657A; The reinforcing agent is ceramic spiral fiber, selected from one or a combination of glass spiral fiber, mullite spiral fiber, magnesium aluminum spinel spiral fiber, carbon spiral fiber, silicon carbide spiral nanowire or ceramic spiral fiber. The ceramic spiral fibers were prepared by referring to the method mentioned in the paper (ZrB2-SiC spiral fibers prepared by combining liquid rope effect with non-solvent-induced phase separation method: Apromising toughening material for ultra-high temperature ceramics, Journal of Advanced Ceramics, 2023, 12(1): 132–144) or the invention patent CN109161331A.

[0010] The core-shell flame retardant filler includes a core material and an outer shell material; the core material is selected from one or more of aluminum hydroxide, magnesium hydroxide, zinc borate or montmorillonite; the outer shell material is a compound material of ammonium polyphosphate and melamine in a mass ratio of 3:1 to 2:1. The coupling agent is selected from one or both of KH-560 or KH-570; The dispersant is silica; The solvent is selected from one or more of dimethylacetamide, cyclohexanone, butyl acetate, methyl silicone oil, or phenyl silicone oil.

[0011] In one embodiment of the present invention, the second semi-crystalline multi-component refractory ceramic powder is the semi-crystalline multi-component ceramic powder of patent CN120117894A. The second silicon-based precursor polymer is selected from one or more of polycarbomethylsilane, polyether-modified polysiloxane, polyimide powder, poly(1,1-dimethylsilazane), 108 silicone rubber, or 109 silicone rubber. The second crosslinking agent is selected from one or more of methyl orthosilicate, ethyl orthosilicate, or trimethoxysilane.

[0012] The second objective of this invention is to provide a method for preparing a ceramic heat-insulating coating, comprising the following steps: Mix the raw materials of component A and component B evenly, and adjust the viscosity to obtain a heat-insulating and fire-resistant coating. The sealing refractory coating is obtained by mixing all the raw materials and adjusting the viscosity.

[0013] The third objective of this invention is to provide a ceramic heat-insulating coating, which is prepared by the above-mentioned ceramic heat-insulating coating.

[0014] The fourth objective of this invention is to provide a method for preparing a ceramic heat-insulating coating, which uses the above-mentioned ceramic heat-insulating coating and includes the following steps: (S1) Apply a heat-insulating and fire-resistant coating to the surface of the pretreated substrate and dry it to obtain a heat-insulating and fire-resistant coating. (S2) A sealing refractory coating is applied to the surface of the heat-insulating and fire-resistant coating obtained in step (S1), and after drying, a sealing refractory coating is obtained, that is, a ceramic heat-insulating coating is obtained on the surface of the substrate.

[0015] In one embodiment of the present invention, the substrate is selected from one of metal, woven fiber surface, fiberglass, graphite, ceramic or aerogel insulation felt; The pretreatment is sandblasting and / or cleaning.

[0016] In one embodiment of the present invention, in step (S1), during the coating process, the coating thickness is controlled to be 100~300μm; The drying process includes a first stage of drying with gradient heating and a second stage of drying. During the first stage of drying, the temperature is 60~80 ℃ and the time is 10~30 min. During the second stage of drying, the temperature is 110~150 ℃ and the time is 5~10 min.

[0017] In one embodiment of the present invention, in step (S2), during the coating process, the coating thickness is controlled to be 25~75 μm; The drying process includes a third stage of drying with gradient heating and a fourth stage of drying; the third stage drying temperature is 80℃ and the time is 10~15 min; the fourth stage drying temperature is 210℃ and the time is 1~5 min.

[0018] The fifth objective of this invention is to provide an application of a ceramic heat-insulating coating in the field of lithium battery casing protection.

[0019] The fifth objective of this invention is to provide an application of a ceramic heat-insulating coating in the field of lithium battery casing protection.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) Ultra-high temperature resistance: The coating system has a heat resistance temperature of up to 2200 ℃, which can provide the ultimate fire protection for the battery.

[0021] (2) Excellent thermal insulation: thermal conductivity is less than 0.12 W / (m·K), which can effectively delay the spread of thermal runaway.

[0022] (3) Excellent durability: It has strong resistance to electrolyte corrosion and its long-term reliability has been verified by accelerated testing.

[0023] (4) Strong adhesion: It has a high bonding force (>6.0 MPa) with a variety of metal shells (Al, stainless steel, Ti alloy), ensuring the coating is stable.

[0024] (5) Flexible construction: The thickness can be precisely controlled within a wide range of 150~600 μm, and it is suitable for various processes such as spraying, scraping, hanging, and electrophoresis.

[0025] (6) Dual protection: The unique double-layer design of "heat insulation and fire-resistant layer and sealing fire-resistant layer" takes into account both heat insulation and environmental protection. Attached Figure Description

[0026] Figure 1 The images show the temperature of the metal back side and the surface morphology of the coating after high-temperature testing in Example 4. Figure 2 The image shows a comparison of the surface state of the 300 μm thick coating sample in Example 5 in its initial preparation state (a) and its state after immersion in electrolyte for 30 days (b). Figure 3 This is a schematic diagram illustrating the application of ceramic heat-insulating coatings. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0028] In the following embodiments, the semi-crystalline multi-element ceramic powder is the semi-crystalline multi-element ceramic powder prepared in Example 1 of patent application CN120117894A; The high-entropy ceramic nanocrystal powder is the high-entropy ceramic nanocrystal powder prepared in Example 1 of patent application CN114516657A; The chopped porous ceramic spiral fiber is the chopped porous ceramic spiral fiber prepared in Example 4 of patent CN109161331A (the chopped porous ceramic spiral fiber prepared in paragraphs 0139 to 0144 of the specification in patent CN109161331A). The core-shell flame retardant filler was prepared according to the method described in patent CN104387061A (using a peristaltic pump-assisted microfluidic system), specifically through the following method: (1) Mix ethanol (as a solvent, or acetone or isopropanol can be selected as appropriate), zinc borate (as core material) and xanthan gum (as a binder, or chitosan can be selected as appropriate), age and degas to obtain core slurry (mass ratio of ethanol, zinc borate and xanthan gum is 30:68.5:1.5), and fill it into a non-solvent tank; (2) Ethanol (as solvent), ammonium polyphosphate (as shell material), melamine (as shell material) and xanthan gum (as binder) are mixed and aged to remove gas to obtain shell slurry (the mass ratio of ethanol, ammonium polyphosphate, melamine and xanthan gum is 30.5:51:17:1.5), which is then filled into a slurry tank; (3) Deionized water is used as the non-solvent in the non-solvent tank; A coaxial nozzle with an inner tube diameter of 0.08 mm and an outer tube diameter of 0.5 mm was selected, and the distance between the coaxial nozzle and the non-solvent tank was set to 10 mm. First, the compressed nitrogen driving pressure system was turned on: the compressed nitrogen cylinder, pressure reducing valve, precision pressure gauge, rotary valve, and rotor flow meter were connected to a driving pressure within 0.1 MPa. By adjusting the rotary valve and peristaltic pump speed (0.5 rpm) on the non-solvent pipeline, the core slurry in the non-solvent tank was allowed to flow out smoothly in droplets. Simultaneously, the rotary valve on the slurry pipeline was opened, and the rotor flow meter was adjusted to a driving pressure within the range of 0.4 MPa to push the outer shell slurry in the slurry tank into the outer tube of the coaxial nozzle. The slurry was observed to drip in droplets (the outer shell slurry encapsulates the core slurry). The slurry droplets were collected with a sieve 3 hours after dripping and dried at room temperature to obtain the core-shell flame retardant filler precursor. (4) The core-shell flame retardant filler precursor obtained in step (3) is dried in air for 24 hours to obtain the core-shell flame retardant filler.

[0029] Unless otherwise specified, all reagents used are commercially available, and all detection methods and techniques used are conventional in this field.

[0030] Example 1 This embodiment provides a method for preparing a ceramic heat-insulating coating, wherein the heat-insulating and fire-resistant coating comprises component A and component B in a mass ratio of 1:2; Component A comprises the following components in parts by weight: 15 parts of the first semi-crystalline multi-component refractory ceramic powder (semi-crystalline multi-component ceramic powder), 30 parts of the first silicon-based precursor polymer (a mixture of polycarbomethylsilane and polyimide powder, with a mass ratio of polycarbomethylsilane to polyimide powder of 2:1), 1 part of the first crosslinking agent (methyl orthosilicate), and 1 part of the crosslinking inhibitor (3-methyl-1-butyn-3-ol). Component B comprises the following components in parts by weight: 10 parts thermal insulation filler (high-entropy ceramic nanocrystal powder), 1 part reinforcing agent (short-cut porous ceramic spiral fiber), 5 parts core-shell flame retardant filler (core slurry is zinc borate; shell slurry is ammonium polyphosphate and melamine in a mass ratio of 3:1), 0.6 parts coupling agent (KH-560), 0.5 parts dispersant (fumed silica), and 15 parts solvent (butyl acetate). The sealing refractory coating comprises 8 parts of second semi-crystalline multi-component refractory ceramic powder (semi-crystalline multi-component ceramic powder), 35 parts of second silicon-based precursor polymer (a mixture of polycarbonyl methylsilane and polyimide powder, with a mass ratio of polycarbonyl methylsilane to polyimide powder of 2:1), and 1 part of second crosslinking agent (ethyl orthosilicate).

[0031] A method for preparing a ceramic heat-insulating coating includes the following steps: Mix all the raw materials of component A and mix all the raw materials of component B; then mix component A and component B together, and adjust the viscosity to 10 Pa∙s using ethyl acetate to obtain the heat-insulating and fire-resistant coating. The raw materials for the sealing refractory coating are mixed evenly, and the viscosity is adjusted to 10 Pa∙s using ethyl acetate to obtain the sealing refractory coating.

[0032] Example 2 This embodiment provides a method for preparing a ceramic heat-insulating coating, using the ceramic heat-insulating coating prepared in Example 1, including the following steps: (S1) The battery pack casing is made of 3003 aluminum alloy square shell as the base; The outer surface of the 3003 aluminum alloy square battery pack shell is roughened by sandblasting, then coated with heat-insulating and fire-resistant coating, and dried to obtain the heat-insulating and fire-resistant coating. During the coating process, the coating thickness is controlled to be 200 μm (wet film). The drying process includes a first stage of drying with gradient heating and a second stage of drying. In the first stage of drying, the temperature is 60 ℃ and the time is 30 min. In the second stage of drying, the temperature is 150 ℃ and the time is 5 min.

[0033] (S2) A sealing refractory coating is applied to the surface of the heat insulation and fire-resistant coating obtained in step (S1), and after drying, a sealing refractory coating is obtained, that is, a ceramic heat-insulating coating is obtained on the surface of the 3003 aluminum alloy square battery pack. During the coating process, the coating thickness is controlled to be 50 μm (wet film). The drying process includes a third stage of drying with gradient heating and a fourth stage of drying; the third stage drying temperature is 80℃ and the time is 10 min; the fourth stage drying temperature is 210℃ and the time is 5 min.

[0034] Tests showed that the coating prepared in this embodiment achieved an adhesion strength of 8.5 MPa on the surface of the 3003 aluminum alloy square battery pack, which can effectively block the influence of external high-temperature heat sources on the battery pack.

[0035] Example 3 This embodiment provides a method for preparing a ceramic heat-insulating coating, using the ceramic heat-insulating coating prepared in Example 1, including the following steps: (S1) A cylindrical battery case made of 304 stainless steel is used as the base (with protection for its inner surface). A heat-insulating and fire-resistant coating is applied to a cylindrical battery casing made of 304 stainless steel and dried to obtain a heat-insulating and fire-resistant coating. The coating process employs leveling technology to control the coating thickness to 250 μm (wet film). The drying process includes a first stage of drying with gradient heating and a second stage of drying. In the first stage of drying, the temperature is 60 ℃ and the time is 25 min. In the second stage of drying, the temperature is 150 ℃ and the time is 10 min.

[0036] (S2) The heat-insulating and fire-resistant coating obtained in step (S1) is coated with a sealing fire-resistant coating and dried to obtain a sealing fire-resistant coating, that is, a ceramic heat-insulating coating is obtained on the surface of the 304 stainless steel cylindrical battery shell. The coating process employs a slurry impregnation technique to control the coating thickness to 125 μm (wet film). The drying process includes a third stage of drying with gradient heating and a fourth stage of drying; the third stage drying temperature is 80℃ and the time is 15 min; the fourth stage drying temperature is 210℃ and the time is 5 min.

[0037] Tests showed that the coating prepared in this embodiment can effectively suppress the impact of high internal temperature on the outer shell during battery thermal runaway, and has good flame retardant effect; and has excellent fracture toughness.

[0038] Example 4 This embodiment provides a method for preparing a ceramic heat-insulating coating, using the ceramic heat-insulating coating prepared in Example 1, including the following steps: (S1) The TC4 titanium alloy battery casing is used as the base (for protection of its inner surface). The inner surface of the TC4 titanium alloy battery casing is coated with a heat-insulating and fire-resistant coating, and after drying, a heat-insulating and fire-resistant coating is obtained. The coating process employs a hanging coating technique to control the coating thickness to 250 μm (wet film). The drying process includes a first stage of drying with gradient heating and a second stage of drying. In the first stage of drying, the temperature is 80 ℃ and the time is 25 min. In the second stage of drying, the temperature is 150 ℃ and the time is 10 min.

[0039] (S2) A sealing refractory coating is applied to the surface of the heat insulation and fire-resistant coating obtained in step (S1), and after drying, a sealing refractory coating is obtained, that is, a ceramic heat-insulating coating is obtained on the surface of the TC4 titanium alloy battery casing. The coating process employs a slurry impregnation technique to control the coating thickness to 125 μm (wet film). The drying process includes a third stage of drying with gradient heating and a fourth stage of drying; the third stage drying temperature is 80℃ and the time is 15 min; the fourth stage drying temperature is 210℃ and the time is 5 min.

[0040] Testing showed that the coating prepared in this embodiment exhibited excellent adhesion to the TC4 titanium alloy battery casing, with an interfacial adhesion exceeding 6.5 MPa, and withstood flame erosion at 1800~2200 ℃ for over 30 seconds (e.g., Figure 1 (As shown).

[0041] The ceramic heat-insulating coating prepared in Example 1 can be used to prepare an anti-explosion and anti-flammation composite coating on the inner surface of a titanium alloy battery casing.

[0042] Example 5 This embodiment provides a method for preparing a ceramic heat-insulating coating, using the ceramic heat-insulating coating prepared in Example 1, including the following steps: (S1) Stainless steel is used as the base material; A heat-insulating and fire-resistant coating is applied to the surface of stainless steel and dried to obtain a heat-insulating and fire-resistant coating. The coating process employs a hanging coating technique, controlling the coating thickness to be 150 μm, 200 μm, 250 μm, and 300 μm (all wet film thicknesses). The drying process includes a first stage of drying with gradient heating and a second stage of drying. In the first stage of drying, the temperature is 80 ℃ and the time is 25 min. In the second stage of drying, the temperature is 150 ℃ and the time is 10 min.

[0043] (S2) Coating the heat-insulating and fire-resistant coating obtained in step (S1) with a sealing fire-resistant coating, and drying it to obtain a sealing fire-resistant coating, that is, obtaining a ceramic heat-insulating coating on the surface of the TC4 titanium alloy battery casing. The coating process employs a slurry impregnation technique to control the coating thickness to 125 μm (wet film). The drying process includes a third stage of drying with gradient heating and a fourth stage of drying; the third stage drying temperature is 80℃ and the time is 15 min; the fourth stage drying temperature is 210℃ and the time is 5 min.

[0044] The samples prepared in this embodiment were immersed in a simulated electrolyte at pH 3.5 and subjected to an accelerated experiment at 65°C for 30 days (e.g., Figure 2 As shown, this represents the electrolyte corrosion resistance equivalent to 10 years at room temperature. Lithium-ion battery electrolyte KLD-FS13, standard: HG-T 4067-2015.

[0045] The results showed that none of the coatings exhibited blistering, peeling, or erosion. Thermal conductivity tests showed that the thermal conductivity of all coatings remained stable between 0.15 and 0.19 W / (m·K).

[0046] In summary, the coating can be applied to the inner or outer surface of battery casings made of aluminum alloy, stainless steel, titanium alloy, etc., through spraying, scraping, hanging, or electrophoresis processes. After two-stage curing at 60℃ and 80℃, it significantly improves the safety protection capability of lithium batteries under extreme thermal conditions. Specifically, the coating prepared above can withstand temperatures above 1800℃. This coating consists of an inner heat-insulating and fire-resistant coating and an outer sealing coating, with a thickness ratio controlled between 1:0.5 and 3:0.5. It has a thermal conductivity of less than 0.2 W / m·K, a high temperature resistance of up to 2200℃, and a bonding strength with the metal casing greater than 8.0 MPa. Its electrolyte resistance performance can be verified through a 65℃ / 30-day accelerated test (equivalent to 10 years at room temperature).

[0047] The above results indicate that the ceramic heat-insulating coating provided by this invention can be used to prepare explosion-proof composite coatings (such as...). Figure 3 (As shown).

[0048] Example 6 This embodiment provides a method for preparing a ceramic heat-insulating coating. Compared with Example 1, except for the following differences, everything else is the same as Example 1: The heat-insulating and fire-resistant coating comprises component A and component B in a mass ratio of 1:3; Component A comprises the following components in parts by weight: 20 parts of the first semi-crystalline multi-component refractory ceramic powder, 40 parts of the first silicon-based precursor polymer, 2 parts of the first crosslinking agent, and 3 parts of the crosslinking inhibitor. Component B comprises the following components in parts by weight: 5 parts thermal insulation filler, 0.5 parts reinforcing agent, 2.5 parts core-shell flame retardant filler, 0.4 parts coupling agent, 0.1 parts dispersant, and 10 parts solvent. The sealing refractory coating comprises 5 parts of second semi-crystalline multi-element refractory ceramic powder, 30 parts of second silicon-based precursor polymer, and 1 part of second crosslinking agent.

[0049] Example 7 This embodiment provides a method for preparing a ceramic heat-insulating coating. Compared with Example 1, except for the following differences, everything else is the same as Example 1: The heat-insulating and fire-resistant coating comprises component A and component B in a mass ratio of 1:2; Component A comprises the following components in parts by weight: 10 parts of the first semi-crystalline multi-component refractory ceramic powder, 20 parts of the first silicon-based precursor polymer, 1 part of the first crosslinking agent, and 0.5 parts of the crosslinking inhibitor. Component B comprises the following components in parts by weight: 15 parts heat-insulating filler, 2 parts reinforcing agent, 10 parts core-shell flame retardant filler, 1 part coupling agent, 0.8 parts dispersant, and 20 parts solvent. The sealing refractory coating comprises 10 parts of second semi-crystalline multi-element refractory ceramic powder, 40 parts of second silicon-based precursor polymer, and 2 parts of second crosslinking agent.

[0050] Example 8 This embodiment provides a method for preparing a ceramic heat-insulating coating. Compared with Example 1, except for the following differences, everything else is the same as Example 1: The heat-insulating and fire-resistant coating comprises component A and component B in a mass ratio of 1:3; Component A comprises the following components in parts by weight: 18 parts of the first semi-crystalline multi-component refractory ceramic powder, 35 parts of the first silicon-based precursor polymer, 2 parts of the first crosslinking agent, and 2 parts of the crosslinking inhibitor. Component B comprises the following components in parts by weight: 8 parts heat-insulating filler, 1 part reinforcing agent, 5 parts core-shell flame retardant filler, 0.8 parts coupling agent, 0.4 parts dispersant, and 15 parts solvent. The sealing refractory coating comprises 7 parts of second semi-crystalline multi-element refractory ceramic powder, 35 parts of second silicon-based precursor polymer, and 1.5 parts of second crosslinking agent.

[0051] The ceramic heat-insulating coatings prepared in Examples 6-8 have comparable performance to the ceramic heat-insulating coating prepared in Example 1.

[0052] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the interpretation of the present invention, without departing from the scope of the invention, should be within the protection scope of the present invention.

Claims

1. A ceramic heat-insulating coating, characterized in that, It includes an inner layer of heat-insulating and fire-resistant coating and an outer layer of sealing and fire-resistant coating that are used independently and in combination; wherein, the heat-insulating and fire-resistant coating includes component A and component B in a mass ratio of 1~2:1~3; Component A comprises the following components in parts by weight: 10-20 parts of the first semi-crystalline multi-component refractory ceramic powder, 20-40 parts of the first silicon-based precursor polymer, 1-2 parts of the first crosslinking agent, and 0.5-3 parts of the crosslinking inhibitor. Component B comprises the following components in parts by weight: 5-15 parts of thermal insulation filler, 0.5-2.0 parts of reinforcing agent, 2.5-10 parts of core-shell flame retardant filler, 0.4-1 parts of coupling agent, 0.1-0.8 parts of dispersant, and 10-20 parts of solvent. The sealing refractory coating comprises 5-10 parts of a second semi-crystalline multi-element refractory ceramic powder, 30-40 parts of a second silicon-based precursor polymer, and 1-2 parts of a second crosslinking agent.

2. The ceramic heat-insulating coating according to claim 1, characterized in that, The first silicon-based precursor polymer is selected from one or more of polycarbomethylsilane, polyether-modified polysiloxane, polyimide powder, poly(1,1-dimethylsilazane), 108 silicone rubber, or 109 silicone rubber. The first crosslinking agent is selected from one or more of methyl orthosilicate, ethyl orthosilicate, or trimethoxysilane; The cross-linking inhibitor is selected from one or more of 3-methyl-1-butyn-3-ol, trimethyl-1-pentyn-3-ol, or 3,5-dimethyl-1-hexyn-3-ol.

3. The ceramic heat-insulating coating according to claim 1, characterized in that, The reinforcing agent is ceramic spiral fiber; The core-shell flame retardant filler includes a core material and an outer shell material; the core material is selected from one or more of aluminum hydroxide, magnesium hydroxide, zinc borate or montmorillonite; the outer shell material is a compound material of ammonium polyphosphate and melamine in a mass ratio of 3:1 to 2:

1. The coupling agent is selected from one or both of KH-560 or KH-570; The dispersant is silica; The solvent is selected from one or more of dimethylacetamide, cyclohexanone, butyl acetate, methyl silicone oil, or phenyl silicone oil.

4. The ceramic heat-insulating coating according to claim 1, characterized in that, The second silicon-based precursor polymer is selected from one or more of polycarbomethylsilane, polyether-modified polysiloxane, polyimide powder, poly(1,1-dimethylsilazane), 108 silicone rubber, or 109 silicone rubber. The second crosslinking agent is selected from one or more of methyl orthosilicate, ethyl orthosilicate, or trimethoxysilane.

5. A method for preparing a ceramic heat-insulating coating as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Mix the raw materials of component A and component B evenly, and adjust the viscosity to obtain a heat-insulating and fire-resistant coating. The sealing refractory coating is obtained by mixing all the raw materials and adjusting the viscosity.

6. A ceramic heat-insulating coating, characterized in that, It is prepared by the ceramic heat-insulating coating according to any one of claims 1 to 4.

7. A method for preparing a ceramic heat-insulating coating, using the ceramic heat-insulating coating according to any one of claims 1 to 4, characterized in that, Includes the following steps: (S1) Apply a heat-insulating and fire-resistant coating to the surface of the pretreated substrate and dry it to obtain a heat-insulating and fire-resistant coating. (S2) A sealing refractory coating is applied to the surface of the heat-insulating and fire-resistant coating obtained in step (S1), and after drying, a sealing refractory coating is obtained, that is, a ceramic heat-insulating coating is obtained on the surface of the substrate.

8. The method for preparing a ceramic heat-insulating coating according to claim 7, characterized in that, In step (S1), during the coating process, the coating thickness is controlled to be 100~300 μm; The drying process includes a first stage of drying with gradient heating and a second stage of drying. During the first stage of drying, the temperature is 60~80 ℃ and the time is 10~30 min. During the second stage of drying, the temperature is 110~150 ℃ and the time is 5~10 min.

9. The method for preparing a ceramic heat-insulating coating according to claim 7, characterized in that, In step (S2), during the coating process, the coating thickness is controlled to be 25~75 μm; The drying process includes a third stage of drying with gradient heating and a fourth stage of drying; the third stage drying temperature is 80 ℃ and the time is 10~15 min; the fourth stage drying temperature is 210 ℃ and the time is 1~5 min.

10. The application of the ceramic heat-insulating coating as described in claim 6 in the field of lithium battery casing protection.

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