Layered silicon carbide skeleton, preparation method thereof and layered silicon carbide skeleton composite phase change material

Abstract

The invention provides a layered silicon carbide skeleton, a preparation method thereof and a layered silicon carbide skeleton composite phase change material, and belongs to the technical field of composite phase change materials. The layered silicon carbide skeleton provided by the invention has a multi-scale pore structure, and the loading rate of the solid-liquid phase change material is improved by limiting the multi-scale pore structure into macropores, mesopores and micropores; the phase change material is effectively prevented from leaking through capillary force formed by the multi-scale pore structure; moreover, during subsequent loading of the solid-liquid phase change material, the solid-liquid phase change material and the silicon carbide microcrystalline layer form a periodically alternating layered structure, so that the interface thermal resistance cumulative effect can be reduced, and the thermal conductivity can be improved; the silicon carbide has excellent corrosion resistance and high thermal conductivity, so that the thermal transport characteristic can be enhanced, and the thermal conductivity can be improved; a continuous lattice oriented silicon carbide microcrystalline structure is formed along the interlayer silicon carbide direction, a long-range ordered phonon transmission channel of a low-scattering interface is constructed, and the thermal conductivity of the layered framework composite phase change material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite phase change materials, and in particular to a layered silicon carbide skeleton and a preparation method thereof, and a layered silicon carbide skeleton composite phase change material. Background Art

[0002] Phase change materials (PCMs) are a unique class of substances with extremely high heats of fusion. At specific temperatures, these materials transition between different phases, storing and releasing large amounts of energy. Due to their remarkable heat storage capacity during phase transitions, PCMs are widely used in a variety of fields, including thermal management, building energy conservation, and electronic equipment cooling.

[0003] Phase change materials are categorized into solid-liquid, solid-solid, and gas-solid types. Solid-liquid phase change materials, with their high latent heat capacity (typically >200 J / g), low volume change rate (<10%), and strong ability to suppress phase separation, dominate large-scale thermal energy storage applications. However, solid-liquid phase change materials have drawbacks such as poor thermal conductivity, leakage, and poor corrosion resistance.

[0004] Existing technologies usually use carriers to load solid-liquid phase change materials to prepare composite phase change materials to solve the problems of poor thermal conductivity, leakage of solid-liquid phase change materials and poor corrosion resistance. At present, composite phase change materials include metal skeleton composite phase change materials, polymer skeleton composite phase change materials, metal organic framework (MOF) composite phase change materials and graphene-based composite phase change materials. However, the existing composite phase change materials have the problem of single performance optimization. For example, phase change graphite powder with phase change energy storage function has high thermal conductivity, but poor pore structure adjustability, low phase change material loading rate, single optional phase change core material, and still has the problems of easy leakage and poor corrosion resistance; while metal organic framework-based composite phase change materials have good corrosion resistance, but low thermal conductivity. Summary of the Invention

[0005] The present invention aims to provide a layered silicon carbide skeleton, a method for preparing the same, and a layered silicon carbide skeleton composite phase change material. The layered silicon carbide skeleton provided by the present invention, when used as a skeleton in a layered silicon carbide skeleton composite phase change material, can simultaneously achieve high thermal conductivity, good corrosion resistance, and low leakage.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a layered silicon carbide skeleton, comprising multiple layers of silicon carbide microcrystalline layers, wherein the number of layers of the silicon carbide microcrystalline layers is more than 5; the silicon carbide microcrystalline layers form a continuous lattice orientation along the direction of the silicon carbide between the layers; the silicon carbide microcrystalline layers have a multi-scale pore structure; the multi-scale pore structure includes macropores, mesopores and micropores.

[0008] Preferably, the multilayer silicon carbide microcrystalline layers are non-covalently bonded.

[0009] The present invention also provides a method for preparing the layered silicon carbide skeleton described in the above technical solution, comprising the following steps:

[0010] (1) stacking and assembling paper sheets with biomass self-adhesive liquid attached to their surfaces and then carbonizing them to obtain a layered carbon skeleton;

[0011] (2) Placing the layered carbon skeleton obtained in step (1) on an inorganic silicon material for diffusion modification to obtain a layered silicon carbide skeleton.

[0012] Preferably, the biomass self-mucin solution in step (1) comprises lignin solution, chitosan solution, fructose solution, pectin solution or fish glue solution.

[0013] Preferably, the mass concentration of the biomass self-mucin in step (1) is 10 to 30 wt%.

[0014] Preferably, the carbonization temperature in step (1) is 1000-1200° C., and the carbonization time is 3-6 hours.

[0015] Preferably, the inorganic silicon material in step (2) includes silicon or silicon monoxide.

[0016] Preferably, the temperature of the diffusion modification in step (2) is 1400-1800° C., and the time of the diffusion modification is 3-6 hours.

[0017] The present invention also provides a layered silicon carbide skeleton composite phase change material, comprising a layered silicon carbide skeleton and a solid-liquid phase change material filled in the pores of the layered silicon carbide skeleton; the layered silicon carbide skeleton is the layered silicon carbide skeleton described in the above technical solution or the layered silicon carbide skeleton prepared by the preparation method described in the above technical solution.

[0018] The present invention also provides a method for preparing the layered silicon carbide skeleton composite phase change material described in the above technical solution, comprising:

[0019] The layered silicon carbide skeleton is immersed in a solid-liquid phase change material solution to obtain a layered silicon carbide skeleton composite phase change material.

[0020] The present invention provides a layered silicon carbide skeleton and multiple silicon carbide microcrystalline layers, wherein the number of layers of the silicon carbide microcrystalline layers is greater than or equal to 10 layers; the silicon carbide microcrystalline layers form a continuous lattice orientation along the direction of the interlayer silicon carbide; the silicon carbide microcrystalline layers have a multi-scale pore structure; the multi-scale pore structure includes macropores, mesopores, and micropores. The layered silicon carbide skeleton provided by the present invention has a multi-scale pore structure, which can increase the loading rate of the solid-liquid phase change material; and the capillary force formed by the multi-scale pore structure effectively prevents leakage of the phase change material; and after loading, the solid-liquid phase change material and the silicon carbide microcrystalline layers form a periodically alternating layered structure, which can reduce the cumulative effect of interfacial thermal resistance and improve thermal conductivity; silicon carbide has excellent corrosion resistance and high thermal conductivity, which can enhance heat transport properties and improve thermal conductivity; and the silicon carbide microcrystalline structure with a continuous lattice orientation along the direction of the interlayer silicon carbide constructs a long-range ordered phonon transmission channel with a low-scattering interface, further improving the thermal conductivity of the layered skeleton composite phase change material. The results of the examples show that the thermal conductivity of the layered silicon carbide skeleton composite phase change material provided by the present invention can reach 2.25 W / m K, and the phase change material loading rate can reach 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a distribution diagram of the multi-level pore structure of the layered silicon carbide skeleton prepared in Example 1;

[0022] Figure 2 A comparison chart of the loading rates of the layered silicon carbide skeleton composite phase change material prepared in Example 2 and the composite phase change materials in References 1 to 5;

[0023] Figure 3 This is a comparison chart of the thermal conductivity of the layered silicon carbide skeleton composite phase change material prepared in Example 2 and the composite phase change materials in References 1 to 5. DETAILED DESCRIPTION

[0024] The present invention provides a layered silicon carbide skeleton, comprising multiple layers of silicon carbide microcrystalline layers, wherein the number of layers of the silicon carbide microcrystalline layers is 100 to 1000 layers or more; the silicon carbide microcrystalline layers form a continuous lattice orientation along the direction of the silicon carbide between the layers; the silicon carbide microcrystalline layers have a multi-scale pore structure; the multi-scale pore structure includes macropores, mesopores and micropores.

[0025] The present invention provides a layered silicon carbide skeleton with multiple silicon carbide microcrystalline layers. In the present invention, the number of silicon carbide microcrystalline layers is five or more. In the present invention, the silicon carbide microcrystalline layers form a continuous lattice orientation along the interlayer silicon carbide direction. By defining the lattice orientation of the silicon carbide microcrystalline layers, the present invention constructs a long-range ordered phonon transmission channel with a low-scattering interface, further improving the thermal conductivity of the layered skeleton composite phase change material.

[0026] In the present invention, the silicon carbide microcrystalline layers are preferably non-covalently bonded. In the present invention, the non-covalent bonding preferably includes hydrogen bonding and van der Waals forces. The present invention can enhance the bonding strength between the layers by limiting the silicon carbide microcrystalline layers to non-covalent bonding.

[0027] In the present invention, the silicon carbide microcrystalline layers have a multi-scale pore structure, and the multi-scale pore structure includes macropores, mesopores and micropores.

[0028] In the present invention, the volume fraction of macropores in the multi-scale pore structure is preferably 45% to 75%. In an embodiment of the present invention, the volume fraction of macropores may be specifically 45%, 50%, 60%, 65%, 70%, or 75%. In the present invention, the volume fraction of mesopores in the multi-scale pore structure is preferably 5% to 35%. In an embodiment of the present invention, the volume fraction of mesopores may be specifically 5%, 10%, 15%, 20%, or 30%. In the present invention, the volume fraction of micropores in the multi-scale pore structure is preferably 20% to 50%. In an embodiment of the present invention, the volume fraction of micropores may be specifically 20%, 25%, 30%, 40%, 45%, or 50%. The present invention further improves the loading rate of the phase change material by limiting the proportions of macropores, mesopores, and micropores.

[0029] In the present invention, the porosity of the multi-scale pore structure is preferably 60-85%. In an embodiment of the present invention, the porosity of the multi-scale pore structure can be specifically 60%, 70%, 80% or 85%. The present invention further improves the loading rate of the phase change material by limiting the porosity of the multi-scale pore structure.

[0030] The layered silicon carbide skeleton provided by the present invention has a multi-scale pore structure. By limiting the multi-scale pore structure to macropores, mesopores and micropores, the porosity is increased, thereby increasing the loading rate of the solid-liquid phase change material; and the capillary force formed by the multi-scale pore structure can effectively prevent the leakage of the phase change material; and when the solid-liquid phase change material is subsequently loaded, the solid-liquid phase change material and the silicon carbide microcrystalline layer form a periodically alternating layered structure, which can reduce the cumulative effect of interfacial thermal resistance and improve thermal conductivity; silicon carbide has excellent corrosion resistance and high thermal conductivity, can enhance heat transport characteristics and improve thermal conductivity; and, a silicon carbide microcrystalline structure with a continuous lattice orientation is formed along the interlayer silicon carbide direction, constructing a long-range ordered phonon transmission channel with a low scattering interface, further improving the thermal conductivity of the layered skeleton composite phase change material; the non-covalent bonding between the silicon carbide microcrystalline layers can enhance the bonding strength between the layers.

[0031] The present invention also provides a method for preparing the layered silicon carbide skeleton described in the above technical solution, comprising the following steps:

[0032] (1) stacking and assembling paper sheets with biomass self-adhesive liquid attached to their surfaces and then carbonizing them to obtain a layered carbon skeleton;

[0033] (2) Placing the layered carbon skeleton obtained in step (1) on an inorganic silicon material for diffusion modification to obtain a layered silicon carbide skeleton.

[0034] The invention stacks and assembles paper sheets with biomass self-adhesive liquid attached to their surfaces and then carbonizes them to obtain a layered carbon skeleton.

[0035] In the present invention, the biomass self-adhesive liquid preferably comprises a lignin solution, a chitosan solution, a fructose solution, a pectin solution, or a fish glue solution. The present invention limits the type of biomass self-adhesive liquid to ensure more complete adhesion between the layers of the layered silicon carbide skeleton. In the present invention, the solvent of the biomass self-adhesive liquid is preferably water. By limiting the solvent of the biomass self-adhesive liquid to water, the present invention avoids the use of chemical reagents, thereby achieving environmental protection.

[0036] In the present invention, the mass concentration of the biomass self-mucin is preferably 10-30 wt%. In embodiments of the present invention, the mass concentration of the biomass self-mucin can be specifically 10 wt%, 20 wt%, or 30 wt%. By limiting the mass concentration of the biomass self-mucin, the present invention further improves the bonding strength between the layered silicon carbide skeleton layers.

[0037] In the present invention, the biomass self-adhesive liquid is preferably attached to the surface of the paper by spraying. In the present invention, the spraying pressure is preferably 0.2-0.5 MPa. In an embodiment of the present invention, the spraying pressure may be specifically 0.2 MPa, 0.3 MPa, 0.4 MPa or 0.5 MPa. In the present invention, the spraying flow rate is preferably 0.3-1.2 L / min. In an embodiment of the present invention, the spraying flow rate may be specifically 0.3 L / min, 0.5 L / min, 0.7 L / min, 0.9 L / min, 1.0 L / min or 1.2 L / min. In the present invention, the diameter of the nozzle hole is preferably 0.5-1.2 mm. In an embodiment of the present invention, the diameter of the nozzle hole may be specifically 0.5 mm, 0.7 mm, 1.0 mm or 1.2 mm. The present invention ensures that the biomass mucus adheres more evenly to the surface of the paper by limiting the spraying parameters.

[0038] The present invention has no special limitation on the density of the spraying, and the spraying can be performed according to the required density.

[0039] The present invention has no particular limitation on the source of the paper, and any paper known in the art can be used. In the present invention, the paper is preferably made from waste biomass materials.

[0040] In the present invention, the paper is preferably subjected to constant temperature and humidity pretreatment before use. In the present invention, the temperature of the pretreatment is preferably 30 to 70°C. In an embodiment of the present invention, the temperature of the pretreatment may specifically be 30°C, 40°C, 50°C, 60°C or 70°C. In the present invention, the humidity of the pretreatment is preferably 80 to 90%. In an embodiment of the present invention, the humidity of the pretreatment may specifically be 80%, 85% or 90%. In the present invention, the time of the pretreatment is preferably 5 to 10 minutes. In a specific embodiment of the present invention, the time of the pretreatment may specifically be 5 minutes, 7 minutes, 9 minutes or 10 minutes. The present invention more fully prevents electrostatic adhesion between each layer of paper by subjecting the paper to constant temperature and humidity pretreatment.

[0041] In the present invention, the assembly method is preferably hot pressing assembly. In the present invention, the pressure of the hot pressing assembly is preferably 1 to 3 MPa. In an embodiment of the present invention, the pressure of the hot pressing assembly may be specifically 1 MPa, 2 MPa or 3 MPa. In the present invention, the temperature of the hot pressing assembly is preferably 70 to 150°C. In an embodiment of the present invention, the temperature of the hot pressing assembly may be specifically 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C. In the present invention, the time of the hot pressing assembly is preferably 3 to 5 minutes. In an embodiment of the present invention, the time of the hot pressing assembly may be specifically 3 minutes, 4 minutes or 5 minutes. The present invention limits the parameters of hot pressing self-assembly to achieve more sufficient non-covalent bonding between silicon carbide microcrystalline layers, thereby enhancing the bonding strength between layers.

[0042] In the present invention, the carbonization temperature is preferably 1000-1200°C. In an embodiment of the present invention, the carbonization temperature may be specifically 1000°C, 1100°C or 1200°C. In the present invention, the carbonization heating rate is preferably 5-10°C / min. In an embodiment of the present invention, the carbonization heating rate may be specifically 5°C / min, 7°C / min or 10°C / min. In the present invention, the carbonization time is preferably 3-6h. In an embodiment of the present invention, the carbonization time may be specifically 1h, 4h, 5h or 6h. In the present invention, the carbonization atmosphere is preferably nitrogen. The present invention limits the carbonization temperature, heating rate and time to ensure more sufficient expansion between paper layers to form a multi-scale pore structure, and to enable the paper to more fully construct a long-range ordered phonon transmission channel with a low scattering interface through the continuous lattice-oriented graphite microcrystal structure formed by carbonization along the interlayer direction.

[0043] After the carbonization is completed, the present invention preferably cools the carbonized product naturally to room temperature to obtain a layered carbon skeleton.

[0044] After obtaining the layered carbon skeleton, the present invention places the layered carbon skeleton on an inorganic silicon material for diffusion modification to obtain a layered silicon carbide skeleton.

[0045] In the present invention, the inorganic silicon material preferably includes silicon or silicon monoxide. The present invention limits the type of inorganic silicon material to ensure that the inorganic silicon material reacts more fully with the carbon in the layered carbon skeleton to form silicon carbide.

[0046] In the present invention, the inorganic silicon material is preferably in the form of particles. As one embodiment of the present invention, the particle size of the inorganic silicon material particles is preferably less than 0.1 μm.

[0047] The present invention has no particular limitation on the placement of the layered carbon skeleton on the inorganic silicon material, as long as the layered carbon skeleton is in full contact with the inorganic silicon material.

[0048] As an embodiment of the present invention, the layered carbon skeleton is placed on the upper layer of a double-layer crucible, and the inorganic silicon material is placed on the lower layer of the double-layer crucible.

[0049] In the present invention, the temperature of the diffusion modification is preferably 1400-1800°C. In an embodiment of the present invention, the temperature of the diffusion modification may specifically be 1400°C, 1500°C, 1600°C, 1700°C or 1800°C. In the present invention, the time of the diffusion modification is preferably 3-6 hours. In an embodiment of the present invention, the time of the diffusion modification may specifically be 3 hours, 4 hours, 5 hours or 6 hours. In the present invention, the carbonization atmosphere is preferably nitrogen. The present invention limits the temperature and time of the diffusion modification to ensure that the inorganic silicon material is more fully gasified and more fully reacts with the carbon in the layered carbon skeleton to form silicon carbide.

[0050] The present invention forms non-covalent bonds between layers of the layered silicon carbide skeleton during the assembly process by attaching biomass self-adhesive liquid to the surface of the paper, thereby enhancing the adhesion between the layers. A multi-scale pore structure is then formed during the carbonization process, and the paper is more fully carbonized along the interlayer direction to form a continuous lattice-oriented graphite microcrystalline structure to obtain a layered carbon skeleton. The paper is then diffused and modified with an inorganic silicon material to obtain a continuous lattice-oriented silicon carbide microcrystalline structure to obtain a layered silicon carbide skeleton. Silicon carbide has excellent corrosion resistance and high thermal conductivity, can enhance heat transport properties, and improve thermal conductivity. In addition, the continuous lattice-oriented silicon carbide microcrystalline structure formed along the interlayer silicon carbide direction constructs a long-range ordered phonon transmission channel with a low scattering interface, further improving the thermal conductivity of the layered skeleton composite phase change material.

[0051] The present invention also provides a layered silicon carbide skeleton composite phase change material, comprising a layered silicon carbide skeleton and a solid-liquid phase change material filled in the pores of the layered silicon carbide skeleton; the layered silicon carbide skeleton is the layered silicon carbide skeleton described in the above technical solution or the layered silicon carbide skeleton prepared by the preparation method described in the above technical solution.

[0052] In the present invention, the solid-liquid phase change material preferably includes paraffin, a hydrated salt, or a molten salt. In the present invention, the hydrated salt preferably includes CuSO4·12H2O, CaSO4·2H2O, or 2CaSO4·H2O. In the present invention, the molten salt preferably includes NaNO3, KNO3, or BaSO4. The present invention limits the type of solid-liquid phase change material to ensure that the resulting layered silicon carbide skeleton composite phase change material has high thermal conductivity.

[0053] The present invention also provides a method for preparing the layered silicon carbide skeleton composite phase change material described in the above technical solution, comprising:

[0054] The layered silicon carbide skeleton is immersed in a solid-liquid phase change material solution to obtain a layered silicon carbide skeleton composite phase change material.

[0055] In the present invention, the immersion time is preferably 3 to 6 hours. In an embodiment of the present invention, the immersion time can be specifically 3 hours, 4 hours, 5 hours or 6 hours. The present invention limits the immersion time to ensure that the solid-liquid phase change material liquid is more fully filled into the layered silicon carbide skeleton.

[0056] In the present invention, the impregnation is preferably performed under vacuum conditions. The present invention limits the impregnation to vacuum conditions to ensure that the solid-liquid phase change material liquid is more fully filled in the multi-scale pore structure of the layered silicon carbide skeleton.

[0057] In the present invention, the solid-liquid phase change material liquid is preferably a melt of the solid-liquid phase change material.

[0058] The present invention immerses a layered silicon carbide skeleton in a solid-liquid phase change material liquid, so that the solid-liquid phase change material is fully filled in the multi-scale pore structure of the layered silicon carbide skeleton, thereby obtaining a layered silicon carbide skeleton composite phase change material that is leak-proof, has a high load rate, high thermal conductivity and good corrosion resistance.

[0059] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0060] Example 1

[0061] A layered silicon carbide skeleton, comprising five layers of silicon carbide microcrystalline layers; a multi-scale pore structure is formed between the silicon carbide microcrystalline layers; the silicon carbide microcrystalline layers form a continuous lattice orientation along the direction of the silicon carbide between the layers; the silicon carbide microcrystalline layers are non-covalently bonded; the volume of the macropores is 20% of the volume of the multi-scale pore structure; the volume of the mesopores is 5% of the volume of the multi-scale pore structure; the volume of the micropores is 75% of the volume of the multi-scale pore structure; and the porosity of the multi-scale pore structure is 85%;

[0062] The preparation method of the layered silicon carbide skeleton comprises the following steps:

[0063] (1) Wood pulp paper with a 10 wt% fish glue solution attached to its surface is stacked to a thickness of 6 mm, and then hot-pressed at a pressure of 1 MPa and a temperature of 70°C for 3 min. Thereafter, the paper is heated to 1000°C at a heating rate of 5°C / min in a nitrogen atmosphere and carbonized for 3 h, and then naturally cooled to room temperature to obtain a layered carbon skeleton; the fish glue solution attached to the surface is sprayed onto the paper using a spray pot with a spray pressure of 0.2 MPa, a spray flow rate of 0.5 L / min, and a nozzle diameter of 0.6 mm; the paper is placed in a constant temperature and humidity chamber at a temperature of 50°C and a humidity of 80% for 10 min before use;

[0064] (2) The layered carbon skeleton obtained in step (1) is placed on the upper layer of a double-layer graphite crucible with a lid, and silicon monoxide particles with a particle size of less than 0.1 μm are placed on the lower layer of the double-layer graphite crucible with a lid, and diffusion modification is performed at a temperature of 1500° C. for 3 hours to obtain a layered silicon carbide skeleton.

[0065] Example 2

[0066] A layered silicon carbide skeleton composite phase change material, comprising the layered silicon carbide skeleton of Example 1 and paraffin wax filled in pores of the layered silicon carbide skeleton;

[0067] The preparation method of the above-mentioned layered silicon carbide skeleton composite phase change material is as follows:

[0068] The layered silicon carbide skeleton prepared in Example 1 was immersed in a paraffin melt in a vacuum drying oven for 5 hours to obtain a layered silicon carbide skeleton composite phase change material.

[0069] Example 3

[0070] The difference between this embodiment and embodiment 1 is that the paper is rice paper, and the rest is the same as embodiment 1, and a layered silicon carbide skeleton is obtained.

[0071] Example 4

[0072] The difference between this embodiment and embodiment 2 is that the layered silicon carbide skeleton prepared in embodiment 3 is used, and the rest is the same as embodiment 2 to obtain a layered silicon carbide skeleton composite phase change material.

[0073] Example 5

[0074] The difference between this embodiment and embodiment 1 is that the fish glue aqueous solution is replaced by a chitosan aqueous solution, and the rest is the same as embodiment 1 to obtain a layered silicon carbide skeleton.

[0075] Example 6

[0076] The difference between this embodiment and embodiment 2 is that the layered silicon carbide skeleton prepared in embodiment 5 is used, and the rest is the same as embodiment 2 to obtain a layered silicon carbide skeleton composite phase change material.

[0077] Example 7

[0078] The difference between this embodiment and embodiment 2 is that the paraffin melt is replaced with ammonium aluminum sulfate dodecahydrate melt, and the rest is the same as embodiment 2 to obtain a layered silicon carbide skeleton composite phase change material.

[0079] The multi-level pore structure distribution of the layered silicon carbide skeleton prepared in Example 1 was measured by BET and mercury intrusion methods. The results are as follows: Figure 1 As shown in the figure, it can be seen that the pore distribution of the composite phase change material prepared in Example 2 is a multi-scale pore structure of micropores, mesopores and macropores.

[0080] The present invention uses the weight method to test the loading rate of the composite phase change material prepared by the methods in Example 2 and References 1 to 5. The results are as follows: Figure 2 As shown in the figure, the loading rates of the layered silicon carbide skeleton composite phase change material prepared in Example 2 of the present invention and the composite phase change materials prepared in References 1 to 5 are 80%, 73.4%, 60%, 70%, 73.4% and 55% respectively. This shows that the layered silicon carbide skeleton composite phase change material prepared in the present invention has a high loading rate.

[0081] The thermal conductivity of the composite phase change materials prepared by the methods in Example 2 and References 1 to 5 was tested by laser flash method. The results are as follows: Figure 3 As shown in the figure, the thermal conductivities of the layered silicon carbide skeleton composite phase change material prepared in Example 2 of the present invention and the composite phase change materials prepared in References 1 to 5 are 2.25 W / m K, 0.301 W / m K, 0.41 W / m K, 0.36 W / m K, 0.66 W / m K, and 0.094 W / m K, respectively. This shows that the layered silicon carbide skeleton composite phase change material prepared in Example 2 of the present invention has high thermal conductivity.

[0082] The anisotropy of the layered silicon carbide skeleton composite phase change material prepared in Example 2 was tested using axial thermal conductivity / radial thermal conductivity, and the result was 2.67, which was significantly improved compared to the anisotropy of the composite phase change materials prepared in References 2 to 4, which were 0, 1.43, and 1.88, respectively. This further demonstrates that the layered silicon carbide skeleton composite phase change material of the present invention has strong heat transfer performance and can effectively reduce heat loss.

[0083] Documents 1 to 5 are:

[0084] 1. YQLi,

[0085] 2. Hongguang Z, Ziye L, Sili Z, et al. Preparation and characteristic of wood-based inorganic composite phase change material with effective anisotropic thermal conductivity for thermal energy storage [J]. Solar Energy Materials and Solar Cells, 2023, 251.

[0086] 3. KYYu, YSLiu, MJJia, YZYang, Bio-based dual-functionalized phase change composite: ultrafast solar-to-thermal conversion and reinforced heatstorage capacity, Energy Fuel 35 (2021) 16162-16173.

[0087] 4. Yaiyue Y, Yazhou W, Qianqian Y, et al. Low-cost, three-dimension, high thermal conductivity, carbonized wood-based composite phase change materials for thermal energy storage [J]. Energy, 2018, 159 (sep. 15): 929-936.

[0088] 5. J. Liang, L. Zhimeng, Y. Ye, W. Yanjun, L. Jingxin, Z. Changlin, Fabrication and characterization of fatty acid / wood-flour composites as novel form-stable phase change materials for thermal energy storage, Energy Build. 171 (2018) 88-99.

[0089] In summary, the layered silicon carbide skeleton provided by the present invention is used as a skeleton for a layered silicon carbide skeleton composite phase change material, which can simultaneously achieve the effects of high thermal conductivity, good corrosion resistance and low leakage.

[0090] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A layered silicon carbide skeleton comprising multiple silicon carbide microcrystalline layers, wherein the number of layers of the silicon carbide microcrystalline layers is 5 or more; the silicon carbide microcrystalline layers form a continuous lattice orientation along the direction of the silicon carbide between the layers; the silicon carbide microcrystalline layers have a multi-scale pore structure; the multi-scale pore structure includes macropores, mesopores and micropores.

2. The layered silicon carbide skeleton according to claim 1, characterized in that The multilayer silicon carbide microcrystalline layers are non-covalently bonded.

3. The method for preparing the layered silicon carbide skeleton according to any one of claims 1 to 2, comprising the following steps: (1) stacking and assembling paper sheets with biomass self-adhesive liquid attached to their surfaces and then carbonizing them to obtain a layered carbon skeleton; (2) Placing the layered carbon skeleton obtained in step (1) on an inorganic silicon material for diffusion modification to obtain a layered silicon carbide skeleton.

4. The preparation method according to claim 3, characterized in that The biomass self-adhesive liquid in step (1) includes lignin solution, chitosan solution, fructose solution, pectin solution or fish glue solution.

5. The preparation method according to claim 4, characterized in that The mass concentration of the biomass self-mucin in step (1) is 10-30 wt%.

6. The preparation method according to claim 3, characterized in that The carbonization temperature in step (1) is 1000-1200° C., and the carbonization time is 3-6 hours.

7. The preparation method according to claim 3, characterized in that The inorganic silicon material in step (2) includes silicon or silicon monoxide.

8. The preparation method according to claim 3, characterized in that The temperature of the diffusion modification in step (2) is 1400-1800° C., and the time of the diffusion modification is 3-6 hours.

9. A layered silicon carbide skeleton composite phase change material, comprising a layered silicon carbide skeleton and a solid-liquid phase change material filled in the pores of the layered silicon carbide skeleton; the layered silicon carbide skeleton is the layered silicon carbide skeleton according to claim 1 or 2 or a layered silicon carbide skeleton prepared by the preparation method according to any one of claims 3 to 8.

10. The method for preparing the layered silicon carbide skeleton composite phase change material according to claim 9, comprising: The layered silicon carbide skeleton is immersed in a solid-liquid phase change material solution to obtain a layered silicon carbide skeleton composite phase change material.

Images