High-temperature composite phase change heat storage material and preparation method thereof

Abstract

The invention discloses a high-temperature composite phase change heat storage material and a preparation method thereof, and belongs to the technical field of composite phase change heat storage materials. The composite phase change material comprises a matrix and a phase change material, the base body is porous ceramic, and the porous ceramic comprises a lining with a porous structure and a surface layer with a porous structure; compared with the pore diameter of the lining, the pore diameter of the surface layer is smaller; the high-temperature salt in a molten state can enter the inside through small holes in the surface layer; the surface layer can avoid leakage of high-temperature salt in a molten state, and the lining provides a storage and phase change space for the high-temperature salt; the porosity of the lining is larger than that of the surface layer, and the phase change material comprises high-temperature salt.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite phase-change heat storage materials, and more specifically, relates to a composite phase-change heat storage material and a preparation method thereof. Background Art

[0002] High-temperature salts such as nitrates, carbonates, chlorides, and sulfates have the advantages of a large heat storage temperature range (200-1000°C), high heat storage density, stable physical / chemical properties, and low price, and are regarded as an ideal high-temperature heat storage material. Its working principle is to store and release heat by absorbing (releasing) heat during the melting (solidification) process of high-temperature salts. However, there are still two major problems in the large-scale application of such heat storage materials: one is that high-temperature salts are highly corrosive and easily corrode their packaging containers; the other is that the thermal conductivity of high-temperature salts is low, about 0.5W / (m·K), resulting in poor heat transfer performance. The current effective solution is to use porous ceramics to micro-encapsulate high-temperature salts to form a shape-stable composite phase change material. This composite heat storage material has the following significant advantages:

[0003] 1) Utilize the capillary force provided by the porous ceramic skeleton to prevent the leakage of molten high-temperature salt and avoid corrosion;

[0004] 2) The porous ceramic skeleton provides a heat transfer channel for high-temperature salt, enhancing heat transfer;

[0005] 3) The composite phase change material can also be in direct contact with the thermal fluid (usually air), effectively reducing the thermal resistance of the heat transfer interface.

[0006] The pore structure of porous ceramics will have an important impact on the comprehensive thermophysical properties of composite phase change materials. The pore structure of the porous ceramics not only needs to consider providing as much attachment space as possible for the high-temperature salt (under a certain volume), which helps to improve the heat storage density, but also needs to ensure that there is a sufficiently large capillary force to prevent the leakage of high-temperature salt, which helps to improve the load stability and heat transfer performance of the high-temperature salt, but at the same time limits the load amount of high-temperature salt (usually ≤50wt%). It can be seen from this that existing porous ceramics can never take into account the potential contribution to the structural stability, heat storage performance, and heat transfer performance of composite phase change materials. Summary of the Invention

[0007] 1. Problem to be solved

[0008] The object of the present invention is to provide a composite phase change material having the advantages of structural stability and good heat storage performance;

[0009] The present invention also provides a method for preparing the composite phase change material.

[0010] 2. Technical solution

[0011] The technical solutions adopted in the present invention are as follows:

[0012] A first aspect of the present invention provides a composite phase change material, the composite phase change material comprising a matrix and a phase change material;

[0013] The porous ceramic comprises:

[0014] An inner layer having a porous structure, and a surface layer having a porous structure;

[0015] The surface layer has pores of smaller diameter than the pores of the inner layer;

[0016] High-temperature salt in a molten state can enter the interior through the small holes in the surface;

[0017] The surface layer can prevent leakage of high-temperature salt in a molten state, and the inner layer provides space for storage and phase change of high-temperature salt;

[0018] The porosity of the inner layer is greater than the porosity of the surface layer;

[0019] The phase change material includes a high temperature salt.

[0020] According to any embodiment of the composite phase change material of the first aspect of the present invention, the loading rate of the phase change material in the matrix is ​​not less than 60wt%;

[0021] The substrate is porous ceramic, and the phase change material includes high-temperature salt;

[0022] The pore size of the inner layer of the porous ceramic is larger than the pore size of the surface layer of the porous ceramic; the porosity of the inner layer of the porous ceramic is larger than the porosity of the surface layer of the porous ceramic;

[0023] The phase change material can enter the interior of the porous ceramic through the surface layer in a molten state;

[0024] The interior provides space for storage and phase change of high temperature salt;

[0025] The surface layer can prevent leakage of the phase change material in a molten state.

[0026] According to the composite phase change material of any embodiment of the first aspect of the present invention, the surface layer has a small pore size compared to the inner pore size;

[0027] The high-temperature salt can enter the interior through the small holes in the surface layer in a molten state;

[0028] The surface layer can prevent leakage of high-temperature salt in a molten state, and the inner layer provides a space for storage and phase change of the high-temperature salt.

[0029] According to the composite phase change material of any embodiment of the first aspect of the present invention, the high-temperature salt includes but is not limited to nitrates (such as potassium nitrate, sodium nitrate, sodium nitrite), carbonates (such as lithium carbonate, sodium carbonate, potassium carbonate), chlorides (such as sodium chloride, potassium chloride, magnesium chloride, calcium chloride), sulfates (such as sodium sulfate, potassium sulfate), and fluoride salts (such as sodium fluoride).

[0030] According to the composite phase change material of any embodiment of the first aspect of the present invention, the loading rate of the phase change material in the matrix is ​​not less than 60 wt %; preferably, the loading rate is 65-75 wt %.

[0031] According to the composite phase change material of any embodiment of the first aspect of the present invention, the phase change material, in liquid state, has a utilization rate of the matrix pores of not less than 70 wt %; preferably, the utilization rate is not less than 75 wt %; and more preferably, the utilization rate is 85-90 wt %.

[0032] According to the composite phase change material of any embodiment of the first aspect of the present invention, the phase change material, in solid state, has a utilization rate of the matrix pores of not less than 60 wt %; preferably, the utilization rate is not less than 65 wt %; further preferably, the utilization rate is 70-80 wt %.

[0033] According to the composite phase change material of any embodiment of the first aspect of the present invention, the inner lining has a porosity of 70-88%; preferably, the inner lining has a porosity of 73-88%; further preferably, the inner lining has a porosity of 78-88%.

[0034] Furthermore, the porosity of the inner lining can be any value within any of the following numerical ranges: 78-88%, 79-88%, 80-88%, 78-87%, 79-87%, 80-87%, 78-86%, 79-86%, 80-86%, 78-85%, 79-85%, 80-85%, 78-84%, 79-84%, 80-84%, 78-83%, 79-83%, 80-83%, 78-82%, 79-82%, 80-82%.

[0035] According to the composite phase change material of any embodiment of the first aspect of the present invention, the surface layer has a porosity of 50-75%. Further, the porosity of the surface layer can be any value taken from any of the following numerical ranges: 50-75%, 52-75%, 55-75%, 58-75%, 60-75%, 62-75%, 65-75%, 67-75%, 70-75%.

[0036] According to the composite phase change material of any embodiment of the first aspect of the present invention, the surface layer has pores with a maximum pore diameter not exceeding 50 micrometers.

[0037] According to the composite phase change material of any embodiment of the first aspect of the present invention, the inner lining has pores with a pore diameter greater than 100 microns.

[0038] According to the composite phase change material of any embodiment of the first aspect of the present invention, the bulk density of the surface layer is greater than the bulk density of the inner layer; the bulk density of the surface layer is greater than the bulk density of the porous ceramic.

[0039] According to the composite phase change material of any embodiment of the first aspect of the present invention, the bulk density of the surface layer is 0.7 to 0.85 g / cm 3 .

[0040] Furthermore, the bulk density of the surface layer can be any value within the following numerical ranges: 0.7 to 0.85 g / cm 3 , 0.72~0.85g / cm 3 , 0.74~0.85g / cm 3 , 0.76~0.85g / cm 3 , 0.78~0.85g / cm 3 , 0.7~0.83g / cm 3 , 0.72~0.83g / cm 3 , 0.74~0.83g / cm 3 , 0.76~0.83g / cm 3 , 0.78~0.83g / cm 3 , 0.7~0.8g / cm 3 , 0.72~0.8g / cm 3 , 0.74~0.8g / cm 3 , 0.76~0.8g / cm 3 , 0.78~0.8g / cm 3 .

[0041] According to the composite phase change material of any embodiment of the first aspect of the present invention, the bulk density of the inner layer is 0.45 to 0.65 g / cm 3 .

[0042] Furthermore, the bulk density of the inner lining can be any value within the following ranges: 0.45 to 0.65 g / cm 3 , 0.47~0.65g / cm 3 , 0.5~0.65g / cm 3 , 0.52~0.65g / cm 3 , 0.55~0.65g / cm 3 , 0.45~0.62g / cm 3, 0.47~0.62g / cm 3 , 0.5~0.62g / cm 3 , 0.52~0.62g / cm 3 , 0.55~0.62g / cm 3 , 0.45~0.6g / cm 3 , 0.47~0.6g / cm 3 , 0.5~0.6g / cm 3 , 0.52~0.6g / cm 3 , 0.55~0.6g / cm 3 .

[0043] According to the composite phase change material of any embodiment of the first aspect of the present invention, the bulk density of the porous ceramic is 0.6 to 0.75 g / cm 3 .

[0044] Furthermore, the bulk density of the porous ceramic can be any value within the following numerical ranges: 0.6 to 0.75 g / cm 3 , 0.62~0.75g / cm 3 , 0.64~0.75g / cm 3 , 0.66~0.75g / cm 3 , 0.68~0.75g / cm 3 , 0.7~0.75g / cm 3 , 0.6~0.73g / cm 3 , 0.62~0.73g / cm 3 , 0.64~0.73g / cm 3 , 0.66~0.73g / cm 3 , 0.68~0.73g / cm 3 , 0.7~0.73g / cm 3 .

[0045] According to the composite phase change material of any embodiment of the first aspect of the present invention, the porous ceramic has a bottom and a top according to the placement direction when in use;

[0046] The top portion has a surface layer, and the surface layer has a thickness t1;

[0047] The bottom portion has a surface layer, and the surface layer has a thickness t2;

[0048] From bottom to top, the maximum thickness of the inner lining is t3;

[0049] The t3 / t1 satisfies 2 to 5.

[0050] Further, the t3 / t1 can be any value taken from any of the following ranges of values: 2-5, 2.2-5, 2.4-5, 2.6-5, 2.8-5, 3-5, 3.2-5, 3.4-5, 3.6-5, 2-4.8, 2.2-4.8, 2.4-4.8, 2.6-4.8, 2.8-4.8, 3-4.8, 3.2-4.8, 3.4-4.8, 3.6-4.8, 2-4.5, 2.2-4.5, 2.4-4.5, 2.6-4.5, 2.8-4.5, 3-4.5, 3.2-4.5, 3.4-4.5, 3.6-4.5, 2-4.2, 2.2-4.2, 2.4-4.2, 2.6-4.2, 2.8-4.2, 3-4.2, 3.2-4.2, 3.4-4.2, 3.6-4.2, 2-4, 2.2-4, 2.4-4, 2.6-4, 2.8-4, 3-4, 3.2-4, 3.4-4, 3.6-4.

[0051] The composite phase change material according to any embodiment of the first aspect of the present application, the t3 / t2 satisfies 2-5.

[0052] Further, the t3 / t2 can be any value taken from any of the following ranges of values: 2-5, 2.2-5, 2.4-5, 2.6-5, 2.8-5, 3-5, 3.2-5, 3.4-5, 3.6-5, 2-4.8, 2.2-4.8, 2.4-4.8, 2.6-4.8, 2.8-4.8, 3-4.8, 3.2-4.8, 3.4-4.8, 3.6-4.8, 2-4.5, 2.2-4.5, 2.4-4.5, 2.6-4.5, 2.8-4.5, 3-4.5, 3.2-4.5, 3.4-4.5, 3.6-4.5, 2-4.2, 2.2-4.2, 2.4-4.2, 2.6-4.2, 2.8-4.2, 3-4.2, 3.2-4.2, 3.4-4.2, 3.6-4.2, 2-4, 2.2-4, 2.4-4, 2.6-4, 2.8-4, 3-4, 3.2-4, 3.4-4, 3.6-4.

[0053] The composite phase change material according to any embodiment of the first aspect of the present application, the pores in the inner part are formed by the action of the pore-forming agent and the foaming agent.

[0054] The second aspect of the present application provides a method for preparing a composite phase change material, the method comprising the steps of:

[0055] (a) preparing a slurry containing a first component; the first component comprising a skeleton material, a pore-forming agent, a curing agent, a sintering aid, a binder, a foaming agent, a foam stabilizer, a solvent;

[0056] Wherein, the content of the sintering aid can be 0;

[0057] (b) preparing a slurry containing a second component;

[0058] The second component includes a skeleton material, a pore-forming agent, a curing agent, a sintering aid, a binder, and a solvent;

[0059] Wherein, the content of the sintering aid can be 0;

[0060] (c) foaming and curing the slurry containing the first component to obtain a molded body containing the first component;

[0061] (d) applying a slurry containing the second component to the surface of the molded body containing the first component and curing the slurry to obtain a molded body coated with the second component;

[0062] (e) subjecting the molded body coated with the second component to a high-temperature sintering treatment to obtain the porous ceramic;

[0063] (f) placing the phase change material in a molten state; allowing the molten phase change material to enter the pores of the matrix; and then cooling to room temperature to obtain a composite phase change material.

[0064] What needs to be explained above is the order of steps (a), (b), and (c). It only requires that step (a) be before step (c), and no other requirements are required.

[0065] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in step (f), the substrate is brought into contact with the phase change material in a molten state (preferably, the substrate is completely immersed in the phase change material in a molten state);

[0066] Then take it out and cool it to room temperature to obtain a composite phase change material.

[0067] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the solid content of the first component slurry is 28 to 50 wt %.

[0068] Further, the solid content of the first component slurry can be any value taken from any of the following ranges: 28-50 wt%, 30-50 wt%, 32-50 wt%, 34-50 wt%, 28-48 wt%, 30-48 wt%, 32-48 wt%, 34-48 wt%, 28-46 wt%, 30-46 wt%, 32-46 wt%, 34-46 wt%, 28-44 wt%, 30-44 wt%, 32-44 wt%, 34-44 wt%, 28-42 wt%, 30-42 wt%, 32-42 wt%, 34-42 wt%, 28-40 wt%, 30-40 wt%, 32-40 wt%, 34-40 wt%, 28-38 wt%, 30-38 wt%, 32-38 wt%, 34-38 wt%, 28-36 wt%, 30-36 wt%, 32-36 wt%, 34-36 wt%.

[0069] According to the method for preparing the composite phase change material of any of the embodiments of the second aspect of the application, in the first component, the solid content of the skeleton material, pore-forming agent, curing agent, sintering aid, and solvent, calculated based on the total amount of the skeleton material, pore-forming agent, curing agent, sintering aid, and solvent, is 28-50 wt%.

[0070] Further, the solid content of the skeleton material, pore-forming agent, curing agent, sintering aid, and solvent, calculated based on the total amount of the skeleton material, pore-forming agent, curing agent, sintering aid, and solvent, can be any value taken from any of the following ranges: 28-50 wt%, 30-50 wt%, 32-50 wt%, 34-50 wt%, 28-48 wt%, 30-48 wt%, 32-48 wt%, 34-48 wt%, 28-46 wt%, 30-46 wt%, 32-46 wt%, 34-46 wt%, 28-44 wt%, 30-44 wt%, 32-44 wt%, 34-44 wt%, 28-42 wt%, 30-42 wt%, 32-42 wt%, 34-42 wt%, 28-40 wt%, 30-40 wt%, 32-40 wt%, 34-40 wt%, 28-38 wt%, 30-38 wt%, 32-38 wt%, 34-38 wt%, 28-36 wt%, 30-36 wt%, 32-36 wt%, 34-36 wt%.

[0071] According to the method for preparing the composite phase change material of any of the embodiments of the second aspect of the application, in the first component, the solid content of the skeleton material, pore-forming agent, curing agent, and solvent, calculated based on the total amount of the skeleton material, pore-forming agent, curing agent, and solvent, is 28-50 wt%.

[0072] Furthermore, based on the total amount of the skeleton material, pore-forming agent, curing agent and solvent, the solid content of the skeleton material, pore-forming agent and curing agent can be any value within any of the following numerical ranges: 28-50wt%, 30-50wt%, 32-50wt%, 34-50wt%, 28-48wt%, 30-48wt%, 32-48wt%, 34-48wt%, 28-46wt%, 30-46wt%, 32-46wt%, 34-46wt%, 28-44wt%, 30-44wt%, 3 2~44wt%, 34~44wt%, 28~42wt%, 30~42wt%, 32~42wt%, 34~42wt%, 28~40wt%, 30~40wt%, 32~40wt%, 34~40wt%, 28~38wt%, 30~38wt%, 32~38wt%, 34~38wt%, 28~36wt%, 30~36wt%, 32~36wt%, 34~36wt%, 28~32wt%, 30~32wt%, 32~32wt%, 34~32wt%.

[0073] It should be noted that, as mentioned above, the solid content of the first component slurry will affect the foaming effect and the foam stabilization effect. Too high a solid content will lead to excessive slurry viscosity, which will have the adverse effect of difficult foaming and cause the problem of low porosity. Too low a solid content will lead to too low slurry viscosity, which will have the adverse effect of unstable foam and cause the problem of long curing cycle and unstable pore structure.

[0074] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in the first component, the mass ratio of the skeleton material, the pore-forming agent, and the foaming agent is (6-7.5): (0.8-2.5): 0.06.

[0075] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in the first component, the mass ratio of the skeleton material, pore-forming agent, curing agent, sintering aid, binder, foaming agent, and foam stabilizer is (650-800):(80-250):(80-130):(0-130):(50-70):(4-8):(1-3).

[0076] Furthermore, in the first component, the mass ratio of the skeleton material, pore-forming agent, curing agent, sintering aid, binder, foaming agent and foam stabilizer is (650-800):(80-130):(80-130):(0-130):(50-70):(4-8):(1-3).

[0077] Furthermore, in the first component, the mass ratios of the skeleton material, pore-forming agent, curing agent, sintering aid, binder, foaming agent and foam stabilizer are preferably (650-800):(80-130):(80-130):(80-130):(50-70):(4-8):(1-3), (700-750):(90-110):((90-110):((90-110):(55-65):(5-7):2.

[0078] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, the solid content of the second component slurry is 40 to 70 wt%.

[0079] Furthermore, the solid content of the second component slurry can be any value within any of the following numerical ranges: 40-70wt%, 42-70wt%, 45-70wt%, 47-70wt%, 50-70wt%, 52-70wt%, 54-70wt%, 56-70wt%, 58-70wt%, 60-70wt%.

[0080] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, based on the total amount of the skeleton material, pore-forming agent, curing agent, sintering aid and solvent, the solid content of the skeleton material, pore-forming agent, curing agent and sintering aid is 40-70 wt%.

[0081] Furthermore, based on the total amount of the framework material, pore-forming agent, curing agent, sintering aid, and solvent, the solid content of the framework material, pore-forming agent, curing agent, and sintering aid can be any value within any of the following numerical ranges: 40-70wt%, 42-70wt%, 45-70wt%, 47-70wt%, 50-70wt%, 52-70wt%, 54-70wt%, 56-70wt%, 58-70wt%, and 60-70wt%.

[0082] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, based on the total amount of the skeleton material, pore-forming agent, curing agent, and solvent, the solid content of the skeleton material, pore-forming agent, curing agent, and sintering aid is 40-70 wt%.

[0083] Furthermore, based on the total amount of the framework material, pore-forming agent, curing agent, sintering aid, and solvent, the solid content of the framework material, pore-forming agent, curing agent, and sintering aid can be any value within any of the following numerical ranges: 40-70wt%, 42-70wt%, 45-70wt%, 47-70wt%, 50-70wt%, 52-70wt%, 54-70wt%, 56-70wt%, 58-70wt%, and 60-70wt%.

[0084] It should be noted that the solid content of the second component slurry described herein will affect the coating effect (wrapping degree and / or uniformity and / or leakage prevention ability) of the slurry containing the second component on the molded body containing the first component. Too much solid content will have an adverse effect on the uniformity of coating the slurry containing the second component on the molded body containing the first component, affecting the uniformity of the thickness of the surface layer of the porous ceramic obtained in the end and the leakage prevention effect; too low a solid content will result in the number of operations of coating the slurry containing the second component on the molded body containing the first component, and will also affect the uniformity and leakage prevention ability of the surface layer of the porous ceramic obtained in the end.

[0085] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in the second component, the mass ratio of the skeleton material to the pore-forming agent is (6-9):(3-5.5).

[0086] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in the second component, the mass ratio of the skeleton material, pore-forming agent, curing agent, sintering aid, and binder is (20-30):(10-20):(0-8):((0-8):(1-6).

[0087] Furthermore, in the second component, the mass ratios of the skeleton material, pore-forming agent, curing agent, sintering aid and binder are preferably (20-30):(10-20):(2-8):((2-8):(1-6), (22-18):(12-15):(3-7):(2-8):(7-6) in sequence.

[0088] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in step (d), the operation of "coating the slurry containing the second component on the surface of the molded body containing the first component and curing" can be repeated multiple times;

[0089] It is preferably repeated 1 to 8 times; more preferably repeated 2 to 5 times; and most preferably repeated 2 to 3 times.

[0090] It should be noted that the number of repetitions described herein will affect the porosity of the porous ceramic finally obtained, the loading rate of high-temperature salt when used as a composite phase change material, and the utilization rate of pores when used as a composite phase change material. Too many or too few repetitions will cause the porosity of the porous ceramic, the loading rate of high-temperature salt when used as a composite phase change material, and the utilization rate of pores when used as a composite phase change material to decrease. From the perspective of obtaining as high a porosity of the porous ceramic as possible, the loading rate of high-temperature salt when used as a composite phase change material, and the utilization rate of pores when used as a composite phase change material, while taking into account the leakage prevention ability when used as a composite phase change material, based on the solid content of the aforementioned slurry containing the second component, it is preferably repeated 2 to 3 times.

[0091] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the porous ceramic has a bottom and a top according to the placement direction during use;

[0092] The top portion has a molded body containing a second component, and the molded body containing the second component has a thickness t1;

[0093] The bottom portion has a molded body containing a second component, and the molded body containing the second component has a thickness t2;

[0094] From bottom to top, the maximum thickness of the molded body containing the first component is t3;

[0095] The t3 / t1 satisfies 2 to 5.

[0096] Furthermore, the t3 / t1 can be any value selected from any of the following numerical ranges: 2-5, 2.2-5, 2.4-5, 2.6-5, 2.8-5, 3-5, 3.2-5, 3.4-5, 3.6-5, 2-4.8, 2.2-4.8, 2.4-4.8, 2.6-4.8, 2.8-4.8, 3-4.8, 3.2-4.8, 3.4-4.8, 3.6-4.8, 2-4.5, 2.2-4.5, 2.4 ~4.5, 2.6~4.5, 2.8~4.5, 3~4.5, 3.2~4.5, 3.4~4.5, 3.6~4.5, 2~4.2, 2.2~4.2, 2.4~4.2, 2.6~4.2, 2.8~4.2, 3~4.2, 3.2~4.2, 3.4~4.2, 3.6~4.2, 2~4, 2.2~4, 2.4~4, 2.6~4, 2.8~4, 3~4, 3.2~4, 3.4~4, 3.6~4.

[0097] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, the t3 / t2 satisfies 2-5.

[0098] Furthermore, the t3 / t2 can be any value selected from any of the following ranges: 2-5, 2.2-5, 2.4-5, 2.6-5, 2.8-5, 3-5, 3.2-5, 3.4-5, 3.6-5, 2-4.8, 2.2-4.8, 2.4-4.8, 2.6-4.8, 2.8-4.8, 3-4.8, 3.2-4.8, 3.4-4.8, 3.6-4.8, 2-4.5, 2.2-4.5, 2.4 ~4.5, 2.6~4.5, 2.8~4.5, 3~4.5, 3.2~4.5, 3.4~4.5, 3.6~4.5, 2~4.2, 2.2~4.2, 2.4~4.2, 2.6~4.2, 2.8~4.2, 3~4.2, 3.2~4.2, 3.4~4.2, 3.6~4.2, 2~4, 2.2~4, 2.4~4, 2.6~4, 2.8~4, 3~4, 3.2~4, 3.4~4, 3.6~4.

[0099] It should be noted that the inventors' research has found that when porous ceramics are used as the matrix for composite phase-change materials, leakage of high-temperature salt is more likely to occur at the "top" or "bottom" during use. Based on this, and in accordance with the present invention's solution, the inventors have further discovered that when t3 / t1 and t3 / t2 meet the aforementioned requirements, leakage can be effectively avoided while also ensuring that the resulting porous ceramics have optimal porosity, optimal high-temperature salt loading when used as a composite phase-change material, and optimal pore utilization when used as a composite phase-change material.

[0100] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in step (c), the curing includes a sealed curing stage and a non-sealed curing stage.

[0101] It should be noted that the inventors' research has found that, in the method for preparing the porous ceramic of the present invention, maintaining both the sealed and non-sealed curing stages during the formation of the molded body containing the first component promotes the structural stability of the resulting porous structure. However, attempts to eliminate the sealed curing stage ultimately resulted in partial collapse of the pore structure.

[0102] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, in step (c), after the foaming is completed, a sealing curing stage is first performed, and then a non-sealing curing stage is performed.

[0103] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, in step (c), the sealing and curing stage lasts for 30 to 60 hours.

[0104] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the temperature of the sealing and curing stage is 15-30°C.

[0105] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the duration of the non-sealed curing stage is 30 to 60 hours.

[0106] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the temperature of the non-sealed curing stage is 15-30°C.

[0107] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the foaming time is 1 to 3 hours.

[0108] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the foaming temperature is 15-30°C.

[0109] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in step (c), stirring is performed during the foaming process, and the stirring speed is 700 to 900 revolutions per minute (r / min).

[0110] Furthermore, in step (c), stirring is performed during the foaming process, and the stirring speed is preferably 720-880 r / min and 750-850 r / min, respectively.

[0111] It should be noted that the stirring speed during the foaming process described herein will affect the porosity of the porous ceramics finally obtained. Appropriate rotation speed and time are conducive to the porous ceramics having optimal porosity.

[0112] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the curing further includes a drying stage.

[0113] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the drying time is 15 to 30 hours.

[0114] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (c), the drying temperature is 40-80°C.

[0115] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in step (d), the curing comprises: drying the slurry containing the second component after coating.

[0116] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (d), the drying time is 5 to 60 minutes.

[0117] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (d), the drying temperature is 60-100°C.

[0118] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (e), the holding time of the high-temperature sintering treatment is 1 to 4 hours.

[0119] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (e), the holding temperature of the drying treatment is 1000-1300°C, preferably 1000-1200°C.

[0120] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (e), the heating rate of the high temperature treatment is 2-10° C. / min.

[0121] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in step (a), the pore-forming agent has a particle size of less than or equal to 100 microns, preferably 60 to 75 microns.

[0122] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, in step (b), the pore-forming agent has a particle size of less than or equal to 100 microns, preferably 60 to 75 microns.

[0123] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in step (a),

[0124] The skeleton material has a particle size of less than or equal to 100 microns; preferably a particle size of 60 to 75 microns;

[0125] The pore-forming agent has a particle size of less than or equal to 100 microns, preferably a particle size of 60 to 75 microns;

[0126] The curing agent has a particle size of less than or equal to 100 microns; preferably a particle size of 60 to 75 microns;

[0127] The sintering aid has a particle size of less than or equal to 100 microns, preferably a particle size of 60 to 75 microns.

[0128] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in step (b),

[0129] The skeleton material has a particle size of less than or equal to 100 microns; preferably a particle size of 60 to 75 microns;

[0130] The pore-forming agent has a particle size of less than or equal to 100 microns, preferably a particle size of 60 to 75 microns;

[0131] The curing agent has a particle size of less than or equal to 100 microns; preferably a particle size of 60 to 75 microns;

[0132] The sintering aid has a particle size of less than or equal to 100 microns, preferably a particle size of 60 to 75 microns.

[0133] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (a), the preparation of the slurry containing the first component comprises the following steps:

[0134] (a.1) Prepare a mixture containing a binder, a foaming agent, and a foam stabilizer;

[0135] (a.2) contacting the framework material, pore-forming agent, curing agent, and sintering aid with the mixed solution.

[0136] It should be noted that, in the process of "preparing a slurry containing the first component" as described herein, the "skeleton material, pore-forming agent, curing agent, sintering aid" and the "binder, foaming agent, foam stabilizer" are added separately and then mixed, which is conducive to obtaining a porous ceramic with optimal porosity.

[0137] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in step (a.1), the preparation of the mixed liquid includes the steps of: (a.11) preparing a solution containing a binder and stirring it; (a.12) bringing the foaming agent and the foam stabilizer into contact with the solution and stirring to obtain a mixed liquid.

[0138] It should be noted that, in the aforementioned process ("preparation of a slurry containing the first component", the "skeleton material, pore-forming agent, curing agent, sintering aid" and the "binder, foaming agent, foam stabilizer" are added separately and then mixed), further adding the "binder" and the "foaming agent, foam stabilizer" separately and then mixing them is more conducive to obtaining a porous ceramic with an optimal porosity.

[0139] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (a.11), the stirring speed is 500 to 700 revolutions per minute (r / min).

[0140] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (a.11), the stirring temperature is 40-70°C.

[0141] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (a.12), the stirring speed is 500 to 700 revolutions per minute (r / min);

[0142] According to the method for preparing a composite phase change material according to any embodiment of the second aspect of the present invention, in step (a.12), the stirring temperature is 15-60°C.

[0143] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, in the first component, the pore former includes a porous structure pore former and / or a non-porous structure pore former; preferably, the pore former is a porous structure pore former.

[0144] It should be noted that in the present invention, the first component forming the porous ceramic "inner lining" is ensured to have a "lining" containing both large and small pores through the combination of a pore-forming agent and a foaming agent. This not only increases the load capacity of the phase change material, but also enhances heat transfer (stepped pore microflow) through the composition of large and small pores within the lining. The pore-forming agent is preferably a porous structure pore-forming agent to ensure the aforementioned inner pore structure.

[0145] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, in the second component, the pore former includes a porous structure pore former and / or a non-porous structure pore former;

[0146] Preferably, the pore-forming agent is a non-porous structure pore-forming agent.

[0147] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in the first component, the particle size of the pore-forming agent does not exceed 100 microns.

[0148] According to the method for preparing a composite phase change material of any embodiment of the second aspect of the present invention, in the second component, the particle size of the pore-forming agent does not exceed 100 microns.

[0149] It should be noted that in the present invention, the combination of a pore-forming agent and a foaming agent in the first component forming the porous ceramic "inner layer" ensures the formation of an "inner layer" containing both large and small pores. Furthermore, the pore-forming agent controls the porous ceramic "surface layer" to have relatively small pores overall, which also promotes a certain degree of microfluidity between the "inner layer" and the "surface layer," thereby enhancing heat transfer.

[0150] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, in the first component, the amount of the pore former added is 5 to 15 wt % based on the total amount of the skeleton material, pore former, curing agent and sintering aid.

[0151] Furthermore, in the first component, based on the total amount of the skeleton material, pore-forming agent, curing agent, and sintering aid, the amount of the pore-forming agent added can be any value within any of the following numerical ranges: 5-15wt%, 6-15wt%, 7-15wt%, 8-15wt%, 9-15wt%, 10-15wt%, 5-14wt%, 6-14wt%, 7-14wt%, 8-14wt%, 9-14wt%, 10~14wt%, 5~13wt%, 6~13wt%, 7~13wt%, 8~13wt%, 9~13wt%, 10~13wt%, 5~12wt%, 6~12wt%, 7~12 wt%, 8~12wt%, 9~12wt%, 10~12wt%, 5~11wt%, 6~11wt%, 7~11wt%, 8~11wt%, 9~11wt%, 10~11wt%.

[0152] According to the composite phase change material preparation method of any embodiment of the second aspect of the present invention, in the first component, the amount of the pore-forming agent added is 5 to 15 wt % based on the total amount of the skeleton material, the pore-forming agent, and the curing agent.

[0153] Furthermore, in the first component, based on the total amount of the skeleton material, the pore-forming agent and the curing agent, the amount of the pore-forming agent added can be any value within any of the following numerical ranges: 5-15wt%, 6-15wt%, 7-15wt%, 8-15wt%, 9-15wt%, 10-15wt%, 5-14wt%, 6-14wt%, 7-14wt%, 8-14wt%, 9-14wt%, 10 ~14wt%, 5~13wt%, 6~13wt%, 7~13wt%, 8~13wt%, 9~13wt%, 10~13wt%, 5~12wt%, 6~12wt%, 7~12w t%, 8~12wt%, 9~12wt%, 10~12wt%, 5~11wt%, 6~11wt%, 7~11wt%, 8~11wt%, 9~11wt%, 10~11wt%.

[0154] It should be noted that the "amount of pore former added" mentioned herein will affect the strength of the obtained porous ceramics. Too much or too little "amount of pore former added" is not conducive to the strength of the porous ceramics.

[0155] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the skeleton material includes but is not limited to: steel slag, solid waste (blast furnace slag, fly ash, red mud, tailings), oxides (aluminum oxide, zirconium oxide, titanium oxide, silicon oxide), carbides (silicon carbide, boron carbide), nitrides (silicon nitride, aluminum nitride), mullite, zircon, and cordierite.

[0156] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the porous structure pore-forming agent includes but is not limited to: diatomaceous earth, kaolin, bentonite, and quartz.

[0157] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the non-porous structure pore-forming agent includes but is not limited to: inorganic pore-forming agents (calcium carbonate, calcite), organic pore-forming agents (corn starch, wheat starch, potato starch, carbon powder, coal powder).

[0158] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the curing agent includes but is not limited to: plaster of Paris (i.e., calcium sulfate hemihydrate (CaSO4·0.5H2O)) and cement.

[0159] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the sintering aid includes but is not limited to: waste glass, sodium feldspar, and potassium feldspar.

[0160] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the binder includes but is not limited to: PVA (polyvinyl alcohol), xanthan gum, polypropylene alcohol, and sodium carboxymethyl cellulose.

[0161] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the foaming agent includes but is not limited to: SDS (sodium dodecyl sulfate), sodium dodecylbenzene sulfonate (SDBS), and soap.

[0162] According to the method for preparing a composite phase change material in any embodiment of the second aspect of the present invention, the foam stabilizer includes but is not limited to: CTAB 12 (dodecyltrimethylammonium bromide), CTAB 16 (cetyltrimethylammonium bromide), acrylamide, polyvinyl alcohol, cellulose, starch.

[0163] According to the method for preparing the porous ceramic of any embodiment of the second aspect of the present invention, the porous ceramic of any embodiment of the first aspect of the present invention can be prepared by the method.

[0164] Any embodiment of any aspect of the present invention can be combined with other embodiments without contradiction. In addition, in any embodiment of any aspect of the present invention, any technical feature can be applied to the technical feature in other embodiments without contradiction.

[0165] Provided that no contradiction arises, any technical feature of any aspect of the present invention or any embodiment of such aspect is also applicable to any other embodiment or any embodiment of any other aspect. Of course, when applicable to each other, the corresponding features may be appropriately modified as necessary. The various aspects and features of the present invention are further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0166] Figure 1 The porous ceramic model provided by the present invention;

[0167] Figure 2 Foam diagram of the preparation of the liquid phase in Example 1 of the present invention;

[0168] Figure 3 The slurry containing the first component after foaming in Example 1 of the present invention;

[0169] Figure 4 The slurry containing the first component in Example 1 of the present invention is subjected to the "sealing and curing stage" treatment;

[0170] Figure 5 The molded body containing the first component after curing and drying according to Example 1 of the present invention;

[0171] Figure 6 The slurry containing the second component in Example 1 of the present invention;

[0172] Figure 7 A diagram showing the process of coating a slurry containing the second component on the surface of a molded body containing the first component and curing to obtain a molded body coated with the second component in Example 1 of the present invention;

[0173] Figure 8 In Example 1 of the present invention, the composite phase change material is prepared using the porous ceramics A-1 to A-4 obtained after high-temperature sintering as a matrix;

[0174] Figure 9 In Example 1 of the present invention, the composite phase change material is prepared using the porous ceramic A-3 obtained after high-temperature sintering as a matrix;

[0175] Figure 10 Actual image of the ceramic obtained from the lining formula of Example 2;

[0176] Figure 11 Actual image of the ceramic obtained from the surface layer formulation of Example 2;

[0177] Figure 12 The inner materials a1, a2, a3, a4, and a5 of the porous ceramic prepared in Example 7;

[0178] Figure 13The inner materials C10, C20, D10, D20, C5D5, C10D10 of the porous ceramics prepared in Example 8;

[0179] Figure 14 The samples C20 / B3, C10 / B3, C5D5 / B3 of the porous ceramics prepared in Example 9;

[0180] Figure 15 The composite phase change materials NaNO3 / C20, NaNO3 / D10, NaNO3 / C5D5, NaNO3 / C20 / B3, NaNO3 / C10 / B3, NaNO3 / C5D5 / B3 prepared in Example 9;

[0181] Figure 16 The load rate of the inner materials of the porous ceramics, the samples of the porous ceramics to high temperature salt in Example 10

[0182] Figure 17 The XRD graphs of the NaNO3 / C20 / B3 chemical compatibility analysis (a), the NaNO3 / D10 / B3 chemical compatibility analysis (b), and the NaNO3 / C5D5 / B3 chemical compatibility analysis (c) in Example 10;

[0183] Figure 18 The DSC graphs of the phase change behavior of the pure phase change material NaNO3, the composite phase change materials NaNO3 / C20, NaNO3 / D10, NaNO3 / C5D5 in the melting and solidification process (a), and the specific heat capacity of the composite phase change materials NaNO3 / C20 / B3, NaNO3 / D10 / B3, NaNO3 / C5D5 / B3 in the temperature range of 100℃-80℃ (b) in Example 10;

[0184] Figure 19 The specific heat capacity of the composite phase change material NaNO3 / C20 / B3 in the temperature range of 100℃-380℃ (a), the specific heat capacity of the composite phase change material NaNO3 / D10 / B3 in the temperature range of 100℃-380℃ (b), and the specific heat capacity of the composite phase change material NaNO3 / C5D5 / B3 in the temperature range of 100℃-380℃ (c) in Example 10. DETAILED DESCRIPTION

[0185] All documents cited in the present application, in their entirety, are hereby incorporated by reference. In the event of a conflict between the present description and the documents incorporated by reference, the present description controls. In addition, the various embodiments of the present application and their equivalents all fall within the scope of the present application. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. By way of example, and without limitation, the following terms as used herein are intended to have the following meanings:

[0186] Unless otherwise indicated, it should be understood that each individual element in a list and each combination of individual elements in that list will be interpreted as a different embodiment. For example, a list of embodiments expressed as "A, B, or C" should be interpreted to include embodiments "A," "B," "C," "A or B," "A or C," "B or C," or "A, B, or C."

[0187] In this disclosure, the singular forms of the articles "a," "an," and "the" also include the corresponding plural reference, and a reference to a specific value includes at least that specific value unless the context clearly dictates otherwise. Thus, for example, a reference to "a substance" is a reference to at least one of that substance and equivalents thereof.

[0188] When items are described by using the conjunction terms "... and / or..." etc., the description should be understood to include any one and all combinations of one or more of the associated listed items.

[0189] In general, the use of the term "about" indicates an approximate value that can vary depending on the desired properties obtained by the disclosed subject matter and will be interpreted in a context-dependent manner based on function. Therefore, one of ordinary skill in the art will be able to interpret a certain degree of difference on a case-by-case basis. In some cases, the number of important figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about". In other cases, a gradient in a range of values ​​can be used to determine the range of differences allowed by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to a value stated in a range includes every value within that range.

[0190] In the present invention, the term "comprising" or "containing" means that various components can be used together in the composition of the present invention. Therefore, the terms "consisting mainly of..." and "consisting of..." are included in the terms "comprising" or "containing".

[0191] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; and the terms used herein include any and all combinations of one or more of the associated listed items.

[0192] Unless otherwise specified, any feature disclosed in this specification may be replaced by other equivalent or alternative features having similar purposes. Unless otherwise specified, each feature is merely an example of a series of equivalent or similar features. The description is merely to help understand the present invention and should not be considered as a specific limitation of the present invention. Where specific conditions are not specified in the examples, the conditions are carried out according to conventional conditions or manufacturer recommendations. Reagents or instruments used without manufacturer's indication are conventional products that can be purchased.

[0193] The porosity in the examples herein was tested using the boiling method.

[0194] The present invention will be further described below with reference to specific embodiments.

[0195] Example 1

[0196] 1. Raw material formula and dosage

[0197] Table 1. Raw material formula of slurry containing the first component

[0198]

[0199]

[0200] Note: The solvent is water

[0201] Table 2. Raw material formula of slurry containing the second component

[0202]

[0203] Note: The solvent is water

[0204] 2. Preparation Process

[0205] Raw material pretreatment: steel slag, diatomaceous earth, calcium carbonate, gypsum, waste glass, SDS, CTAB 12 Grind and pass through a 200-mesh sieve for later use;

[0206] 1. Preparation of a Molded Body Containing the First Component

[0207] 1) Preparation of PVA solution: 10 wt% PVA was mixed with water and stirred at 80°C and 600 rpm for 2 h to prepare a 10 wt% PVA solution;

[0208] 2) Preparation of liquid phase (taking the total volume of the solution as 30 ml, PVA, SDS, CTAB 12 For external doping): 0.06g SDS, 0.02g CTAB 12 6g PVA solution was poured into 14.1g water and stirred at 55℃ and 600r / min for 30min to obtain the following Figure 2 foamed solution as shown in FIG. 1A;

[0209] 3) Preparation of the slurry containing the first component: 7.35 g of steel slag, 1.05 g of diatomite, 1.05 g of plaster of Paris, and 1.05 g of waste glass were thoroughly mixed in a mortar to obtain a solid phase, and the solid phase was mixed with the foamed solution to obtain the slurry containing the first component;

[0210] 4) Foaming: the slurry containing the first component was stirred at 800 r / min at room temperature for 2 h to complete the foaming, and a foamed slurry containing the first component after the foaming was completed was obtained as shown in FIG. 1B; Figure 3

[0211] 5) Sealed curing: referring to FIG. 1C, the above slurry was poured into a mold, sealed with a plastic wrap, and cured at room temperature for 48 h; Figure 4

[0212] 6) Non-sealed curing: after the sealed curing was completed, the plastic wrap was removed, and non-sealed curing was performed at room temperature for 48 h;

[0213] 7) Drying: after the non-sealed curing was completed, the sample was placed in an oven (60°C) and dried for 24 h to obtain a shaped body containing the first component as shown in FIG. 1D; Figure 5

[0214] 2, Preparation of the shaped body containing the second component

[0215] 1) Preparation of a PVA solution: 10 wt.% PVA was mixed with water, and stirred at 600 r / min at 80°C for 2 h to prepare a 10 wt.% PVA solution;

[0216] 2) Preparation of the slurry containing the second component: (taking 30 ml of the total volume of the solution as an example, PVA is externally added) 12 g of the PVA solution was poured into 4.2 g of water and stirred uniformly; 7.5 g of steel slag, 4.5 g of calcium carbonate, 1.5 g of plaster of Paris, and 1.5 g of waste glass were thoroughly mixed in a mortar, and then poured into the above solution, and stirred at 600 r / min at room temperature for 30 min to obtain the slurry containing the second component as shown in FIG. 2A; Figure 6

[0217] 3) Preparation of the shaped body containing the second component: referring to FIG. 2B, the shaped body containing the first component was immersed in the slurry containing the second component for 10 s, and after being taken out, was placed in an oven (80°C) and dried for 10 min, which was one coating process; the operation could be repeated as needed; Figure 7

[0218] ​​​​​It should be noted that after the first coating in step 3) of this embodiment is completed, the thickness of the surface layer of the porous ceramic obtained after the final treatment in step 4) is about 1 to 1.5 mm;

[0219] In this embodiment, the following Figure 1 The porous ceramic samples A-1 to A-3 and the porous ceramic inner material A-4 are shown:

[0220] The porous ceramic inner material A-4 obtained after 0 coatings does not have a "surface layer" material; in terms of method, after completing "1. Preparation of a molded body containing the first component", "4) high-temperature sintering" is directly performed, and the "1) preparation of a PVA solution, 2) preparation of a slurry containing the second component, and 3) preparation of a molded body coated with the second component" in "2. Preparation of a molded body coated with the second component" are not performed.

[0221] Porous ceramic sample after 2 coatings (A-3);

[0222] Porous ceramic sample (A-2) after three coatings;

[0223] Porous ceramic sample (A-1) after 5 coatings.

[0224] 3. Basic performance test

[0225] 1) In addition, taking the porous ceramic lining material A-4 as an example, the key parameters of the porosity tested by the boiling method in this embodiment are shown in Table 3 below:

[0226] Table 3. Performance test of porous ceramic lining material A-4

[0227] <![CDATA[干重(m1) / g]]> float weight (m2) / g <![CDATA[湿重(m3) / g]]> Porosity (P) / % <![CDATA[体密(ρ)g / cm 3 ]]> 3.6 2.4 8.64 80.8 0.58

[0228] 4. Preparation and performance testing of composite phase change materials

[0229] 1) In this embodiment, the porous ceramic samples A-1 to A-3 and the inner material A-4 of the porous ceramic are used as the matrix to prepare the following Figure 8 The composite phase change material shown is as follows: Sodium nitrate is used as the phase change material, heated to 340°C (molten state), the porous ceramic is immersed in molten sodium nitrate for 2 hours, and then taken out and cooled to room temperature with the furnace to obtain a composite phase change material. The loading rate of the porous ceramic for high-temperature salt and the pore utilization rate of the porous ceramic when loading high-temperature salt are tested.

[0230] 2) The performance test of the porous ceramic samples is shown in Table 4 below:

[0231] Table 4. Performance test of porous ceramic samples

[0232] sample Porosity (P) / % <![CDATA[体密度(ρ) / g / cm 3 ]]> Loading rate / wt% Porosity utilization (solid / liquid) A-1 71.5％ 0.71 60.3 66.8％ / 78.8％ A-2 72.3％ 0.74 61.6 72.7％ / 85.9％ A-3 74.4％ 0.69 65.2 76.9％ / 90.9％ A-4 80.8％ 0.58 66.5 63.1％ / 74.7％

[0233] In addition, according to the test, in this embodiment, the porosity (P) of the surface layer formed by the slurry containing the second component coated on the surface of the molded body containing the first component is 73.3%, and the bulk density (ρ) is 0.78 g / cm 3 .

[0234] As can be seen from Table 4, A-3 is the porous ceramic with the best performance currently obtained. The following are other relevant information parameters of sample A-3:

[0235] Reference Figure 9 As shown, according to the placement direction during use, the porous ceramic has a bottom and a top; the top has a molded body containing the second component, and the molded body containing the second component has a thickness t1; the bottom has a molded body containing the second component, and the molded body containing the second component has a thickness t2; from the bottom to the top, the maximum thickness of the molded body containing the first component is t3;

[0236] The top and bottom surface layers (also called shells, formed by coating the slurry containing the second component twice) of sample A-3 have thicknesses t1 and t2 of 3 mm, and the inner layer (also called core, formed by curing and drying the slurry containing the first component) t3 has a thickness of 11 mm.

[0237] Example 2

[0238] This embodiment provides a method for preparing porous ceramics. Specifically,

[0239] The porous ceramic surface layer (such as Figure 11 As shown), inside (as Figure 10 The raw materials and amounts are as follows:

[0240] Lining formula: 50% steel slag + 50% calcium carbonate (0.15-0.5mm) + 30% waste glass

[0241] Surface layer formula: 100% steel slag + 30% waste glass

[0242] Preparation method: Fabric according to the following structure, with the lining formula in the middle and the surface formula around; press at 10MPa for 1min; keep warm at 1100℃ for 2h.

[0243] The performance test of the prepared samples is shown in Table 5 below:

[0244] Table 5. Performance test of samples prepared in Example 2

[0245] structure Porosity (P) / % <![CDATA[体密度(ρ) / g / cm 3 ]]> Inside 52.4 1.36 surface layer 46.6 1.41

[0246] Example 3

[0247] The preparation method of the porous ceramic inner material provided in this embodiment is basically the same as that of the porous ceramic inner material A-4 in Example 1, with the only difference being that "5) Sealing and Curing" is directly replaced by "6) Non-Sealing and Curing". Specifically:

[0248] In this example, after "4) foaming," the material was directly cured at room temperature for 96 hours in an unsealed state. Then, "7) drying" was performed to obtain a molded body containing the first component. The remaining steps were the same as those for preparing porous ceramic lining material A-4 in Example 1, ultimately yielding porous ceramic lining material B-1.

[0249] Testing of the porous ceramic inner material B-1 revealed that it had a partially collapsed pore structure and a porosity of less than 60%.

[0250] Example 4

[0251] This example provides a method for preparing a porous ceramic lining material. This method is essentially the same as the preparation of porous ceramic lining material A-4 in Example 1, differing only in the stirring speed and stirring time during step "4) foaming." Specifically: Porous ceramic lining material B-2: stirring speed 600 r / min, stirring time 1 hour;

[0252] Porous ceramic lining material B-3: stirring speed 600 r / min, stirring time 2 h;

[0253] Porous ceramic lining material B-4: stirring speed 1000 r / min, stirring time 1 h;

[0254] Porous ceramic lining material B-5: stirring speed 1000 r / min, stirring time 2 h;

[0255] Porous ceramic lining material B-6: stirring speed 800 r / min, stirring time 3 h.

[0256] Example 5

[0257] This embodiment provides a method for preparing the inner material of porous ceramics, which is basically the same as the preparation of the inner material A-4 of the porous ceramics in Example 1, with the only difference being that the following operations are performed to replace the "step 2) preparation of the liquid phase" and "step 3) preparation of the slurry containing the first component" in "1. Preparation of a molded body containing the first component" in Example 1.

[0258] The specific operation is as follows: 7.35g steel slag, 1.05g diatomaceous earth, 1.05g gypsum, and 1.05g waste glass are fully mixed in a mortar to obtain a solid phase; the solid phase, 0.06g SDS, and 0.02g CTAB are mixed. 12, 6 g of PVA solution was poured into 14.1 g of water, and stirred at 55°C and 600 r / min for 30 min to obtain a slurry containing the first component;

[0259] The rest of the preparation was the same as that of sample A-4 in Example 1, and finally a porous ceramic lining material B-7 was obtained.

[0260] Example 6

[0261] This embodiment provides a method for preparing the inner material of a porous ceramic, which is basically the same as the preparation of the inner material A-4 of the porous ceramic in Example 1, except that the amount of diatomaceous earth used in the solid phase is different. Specifically:

[0262] Porous ceramic lining material B-8: Diatomaceous earth is used in a relatively low amount, such as 1%, and the remaining raw materials, amounts, and operations are the same as in Example 1;

[0263] Porous ceramic lining material B-9: In the solid phase, the proportion of diatomaceous earth is increased to 20 wt %, and the remaining raw materials, amounts, and operations are the same as in Example 1;

[0264] The porosities of the porous ceramic lining materials B2 to B9 prepared in Examples 4 to 6 above are shown in Table 6.

[0265] Table 6. Porosity of the inner materials B2 to B9 of the porous ceramics prepared in Examples 4 to 6

[0266] Porous ceramic lining material A-4 B-2 B-3 B-4 B-5 B-6 B-7 B-8 B-9 Porosity (P) / % 80.8 68 74 66 72 78 62 76 74

[0267] Example 7

[0268] This embodiment provides five porous ceramic lining materials containing a composite system of a foaming agent and a foam stabilizer in different ratios. The raw material formulas and amounts are shown in Tables 7 and 8.

[0269] Table 7. Solid phase raw material formula of slurry containing the first component

[0270]

[0271] Table 8. Liquid raw material formula of slurry containing the first component

[0272]

[0273] Note: The solvent is water

[0274] 1. Preparation process

[0275] Raw material pretreatment: steel slag, gypsum, waste glass, SDS, CTAB 12 Grind and pass through a 200-mesh sieve for later use;

[0276] 1. Preparation of a Molded Body Containing the First Component

[0277] 1) Preparation of liquid phase: Using water as solvent, a mixture containing SDS and CTAB at the concentrations shown in Table 8 was prepared. 12 The liquid phase was stirred at 55 °C and 600 r / min for 30 min;

[0278] 3) preparing a slurry containing the first component: thoroughly mixing steel slag, plaster of Paris, and waste glass in a mortar to obtain a solid phase, and mixing the solid phase with the foam solution to obtain a slurry containing the first component with a solid phase content of 35 wt%;

[0279] 4) Foaming: This step is the same as in Example 1;

[0280] 5) Sealing and curing: This step is the same as in Example 1;

[0281] 6) Non-sealed curing: This step is the same as in Example 1;

[0282] 7) Drying: This step is the same as in Example 1;

[0283] In summary, the inner materials a1, a2, a3, a4, and a5 of the porous ceramics are obtained respectively, wherein the morphologies of a1, a2, and a3 are as follows: Figure 12 shown.

[0284] 2. Basic performance test

[0285] In this embodiment, the performance tests of the porous ceramic lining materials a1, a2, a3, a4, and a5 are shown in Table 9 below:

[0286] Table 9. Performance test of porous ceramic lining materials a1, a2, a3, a4, and a5

[0287] sample Porosity (%) <![CDATA[体密度(g / cm 3 )]]> a1 65.7 1.2 a2 64.3 1.13 a3 76.3 0.58 a4 72.7 0.66 a5 67.5 0.99

[0288] Example 8

[0289] This example adopts a strict control experiment design to systematically investigate the effect of pore-forming agent type and content on the internal material structure and performance of porous ceramics. Based on the previously optimized ceramic slurry formula (solid content 35wt%, foaming agent and foam stabilizer ratio fixed at SDS:CTAB 12 =3:1), and six representative experimental systems were designed: the raw material formulas and dosages are shown in Tables 10 and 11.

[0290] Table 10. Liquid raw material formula of slurry containing the first component

[0291]

[0292]

[0293] Table 11. Raw material formulation of the slurry containing the first component

[0294] sample Steel slag (wt.%) Calcium carbonate (wt%) Diatomaceous earth (wt%) Plaster of Paris (wt%) Waste glass (wt%) C10 70 10 0 10 10 C20 60 20 0 10 10 D10 70 0 10 10 10 D20 60 0 20 10 10 C5D5 70 5 5 10 10 C10D10 60 10 10 10 10

[0295] I. Preparation process

[0296] The raw material pretreatment and the preparation process can refer to the section "I. Preparation of the shaped body containing the first component" of Example 1. Finally, the samples C10, C20, D10, D20, C5D5, C10D10 of the inner material of the porous ceramic are obtained, respectively, and the morphology thereof is shown in Figure 13

[0297] II. Basic performance test

[0298] The performance test of the samples C10, C20, D10, D20, C5D5, C10D10 of the inner material of the porous ceramic obtained in this example is shown in Table 12 as follows:

[0299] Table 12. Performance test of the samples C10, C20, D10, D20, C5D5, C10D10 of the inner material of the porous ceramic

[0300] sample Porosity (%) <![CDATA[体密度(g / cm 3 )]]> C10 68.4％ 0.88 C20 71.8％ 0.85 D10 80.4％ 0.56 D20 74.2％ 0.72 C5D5 73.3％ 0.79 C10D10 71.6％ 0.73

[0301] Example 9

[0302] In this example, the samples C20, D10, C5D5 of the inner material of the porous ceramic prepared in the aforementioned Example 8 are used as the core, and the slurry containing the second component shown in Table 13 below is used as the shell raw material to prepare the samples (C20 / B3, C10 / B3 and C5D5 / B3) of the porous ceramic.

[0303] Table 13. Raw material formulation of the slurry containing the second component

[0304]

[0305] Note: the solvent is water

[0306] I. Preparation process

[0307] The raw material pretreatment and the preparation process can refer to the section "II. Preparation process" of the inner material A-4 of Example 1. Finally, the samples (C20 / B3, C10 / B3 and C5D5 / B3) of the porous ceramic after 2 times of coating, the top and bottom surface layers (which can also be referred to as the shell, formed by 2 times of coating of the slurry containing the second component) of each sample have a thickness t1, t2 of 3 mm, and the thickness t3 of the inner layer (which can also be referred to as the core, formed by curing and drying of the slurry containing the first component) is 11 mm.

[0308] ​Finally, the morphology of each sample is as follows Figure 14 shown.

[0309] 2. Basic performance test

[0310] The performance of the porous ceramic samples C20 / B3, C10 / B3 and C5D5 / B3 obtained in this embodiment was tested and shown in Table 14 below:

[0311] Table 14. Performance test of porous ceramics C20 / B3, C10 / B3, and C5D5 / B3

[0312] sample Porosity (%) <![CDATA[体密度(g / cm 3 )]]> C20 / B3 71.1 0.83 D10 / B3 73.1 0.79 C5D5 / B3 71.6 0.81

[0313] Example 10

[0314] Composite phase change material loading performance and leakage tests were performed on the porous ceramic lining material samples C20, D10, and C5D5 prepared in the aforementioned embodiment, as well as the porous ceramic samples C20 / B3, C10 / B3, and C5D5 / B3 prepared in the aforementioned embodiment.

[0315] The porous ceramic inner material samples C20, D10, C5D5 porous ceramic samples C20 / B3, C10 / B3 and C5D5 / B3 were prepared as the matrix. Figure 15 The composite phase change materials shown (NaNO3 / C20, NaNO3 / D10, NaNO3 / C5D5, NaNO3 / C20 / B3, NaNO3 / C10 / B3, NaNO3 / C5D5 / B3): Sodium nitrate is used as the phase change material, heated to 340°C (molten state), the porous ceramic is immersed in molten sodium nitrate for 2 hours, and then taken out and cooled to room temperature with the furnace to obtain a composite phase change material. The loading rate of the porous ceramic for high-temperature salt and the pore utilization rate of the porous ceramic when loading high-temperature salt are tested.

[0316] Furthermore, the composite material was subjected to 15 thermal cycle tests for leakage stability. The thermal cycle consisted of heating from 250°C to 350°C, holding at 350°C for 10 minutes, and then cooling to 250°C. This constituted one cycle, with both the heating and cooling rates being 5°C / min.

[0317] Table 15. Test of the inner material of porous ceramics and the loading rate of porous ceramic samples to high temperature salt

[0318] Composite phase change materials Loading rate after 15 cycles (wt.%) Theoretical loading rate (wt.%) <![CDATA[NaNO3 / C20]]> 53.6 62.0 <![CDATA[NaNO3 / C20-B3]]> 57.3％ 60.1 <![CDATA[NaNO3 / D10]]> 61.8％ 73.3 <![CDATA[NaNO3 / D10-B3]]> 64.6％ 65.5 <![CDATA[NaNO3 / C5D5]]> 60.5％ 63.9 <![CDATA[NaNO3 / C5D5-B3]]> 68.8％ 69.8

[0319] As shown in Table 15, the test results fully demonstrate the significant advantages of the core-shell structure design: after the cycle test, the loading rate of the high-temperature salt NaNO3 loaded by the porous ceramic lining material sample without a shell structure (such as C20) was reduced to 53.6%, while the loading rate of the porous ceramic sample C20-B3, which uses the same matrix but has a core-shell structure, was reduced by 57.3%. Of particular note, the optimized porous ceramic samples D10-B3 and C5D5-B3 demonstrated excellent anti-leakage performance, with loading rates exceeding 60%.

[0320] In addition, in terms of the proportion of pore-forming agents, the porous ceramic samples (D10-B3, C5D5-B3) with a pore-forming agent addition amount of 10wt% have a higher loading rate than the porous ceramic sample C20-B3 with a pore-forming agent addition amount of 20wt%; the porous ceramic sample C5D5-B3 prepared by including both calcium carbonate and diatomaceous earth pore-forming agents has a higher loading rate than the porous ceramic sample D10-B3 prepared by including only diatomaceous earth as a single pore-forming agent.

[0321] Table 16. Test of the inner material of porous ceramics and the loading rate of porous ceramic samples to high temperature salt

[0322]

[0323] According to Table 16 and Figure 16 It can be seen that the porous ceramic sample with shell structure has a more stable loading rate;

[0324] like Figure 16As shown, the mass loss during thermal cycling exhibits a typical three-stage evolution pattern: the initial stage (0-5 cycles) is characterized by rapid weight loss, accounting for approximately 60% of the total weight loss, primarily due to the volatilization of the high-temperature salt NaNO3 from the surface and near-surface regions of the material; the intermediate stage (5-10 cycles) is characterized by a significant slowdown in the weight loss rate, entering a relatively stable weight loss phase; and the late stage (10-15 cycles) is characterized by a near-equilibrium state, with the weight loss trend becoming stable. Overall, the porous ceramic samples with a shell structure exhibit significantly lower mass loss than the inner material samples of the porous ceramic without a shell structure, indicating that the microporous shell design within the core-shell structure effectively controls the leakage rate to below 1%, demonstrating excellent long-term stability. The porous ceramic samples with a 10 wt% pore-forming agent addition (D10-B3 and C5D5-B3) exhibit relatively lower mass loss than the porous ceramic sample C20-B3 with a 20 wt% pore-forming agent addition. The mass losses of the porous ceramic sample C5D5-B3 prepared with both calcium carbonate and diatomaceous earth as two pore-forming agents, and the porous ceramic sample D10-B3 prepared with only diatomaceous earth as a single pore-forming agent, both do not exceed 0.5%. However, it is worth mentioning that the porous ceramic sample C5D5-B3 effectively regulates the pore distribution characteristics of the material due to the synergistic effect of the two pore-forming agents, calcium carbonate and diatomaceous earth, while ensuring a high loading rate (>60wt%), and significantly improves the anti-leakage performance.

[0325] Steel slag is an industrial solid waste with a complex chemical composition, which may cause chemical reactions with high-temperature salt-based phase change materials, thereby weakening the heat storage capacity of the composite phase change materials. Therefore, chemical compatibility is the most basic requirement for the preparation of solid waste-based composite phase change materials. The chemical compatibility can be judged by the mineral phase composition relationship between the composite phase change material, porous ceramic sample and phase change material. Specifically, when the diffraction peak of the composite phase change material happens to be the physical superposition of the diffraction peak of the porous ceramic sample and the phase change material, it can be determined that the porous ceramic sample and the phase change material are only physically combined and no chemical reaction occurs, and the composite phase change material has good chemical compatibility. Taking NaNO3 / C5D5 / B3 as an example, the mineral phase composition of the composite phase change material, porous ceramic sample and phase change material was further studied by XRD, such as Figure 17 As shown in the figure, the diffraction peak of NaNO3 / C5D5 / B3 is a physical superposition of the diffraction peaks of C5D5 / B3 and NaNO3. Therefore, the porous ceramic sample (C5D5 / B3) has good chemical compatibility with the high-temperature salt-based phase change material (NaNO3).

[0326] In addition, the phase change behavior of the composite phase change material during melting and solidification was investigated using a differential scanning calorimetry (DSC) system and compared with that of the pure phase change material ( Figure 18(a)). Experimental results show that the melting point and freezing point of pure sodium nitrate (NaNO3) are 309°C and 300°C, respectively, with corresponding melting and solidification enthalpies of 171.5 J / g and 170.1 J / g, respectively. The phase transition temperatures of the three composite phase change materials (NaNO3 / C20 / B3, NaNO3 / D10 / B3, and NaNO3 / C5D5 / B3) are essentially the same as those of pure sodium nitrate, but their phase transition enthalpies are significantly lower, with melting and solidification enthalpies of 99.7 J / g and 99.8 J / g, 109.2 J / g and 110.0 J / g, and 117.2 J / g and 117.4 J / g, respectively.

[0327] In addition, the sensible heat properties of composite phase change materials are closely related to their specific heat behavior. To this end, we further measured the specific heat capacity of the material in the temperature range of 100℃~380℃ ( Figure 18 (b) Figure 19 Based on this, the thermal storage density of the composite materials can be calculated in two ways: one is to superimpose the sensible and latent heat of the pure phase-change material NaNO₃ and the sensible heat of the porous ceramic sample; the other is to directly integrate the specific heat capacity of the composite material within the target temperature range. Using the latter method, we calculated that the thermal storage densities of the three composite phase-change materials within the range of 100°C to 380°C were 555.4 J / g, 617.1 J / g, and 577.6 J / g, respectively.

[0328] Any embodiment of any aspect of the invention can be combined with other embodiments without contradiction. In addition, in any embodiment of any aspect of the invention, any technical feature can be applied to the technical feature in other embodiments without contradiction.

Claims

1. A composite phase change material, characterized in that: The composite phase change material comprises a matrix and a phase change material, wherein the loading rate of the phase change material in the matrix is ​​not less than 60 wt %; The substrate is porous ceramic, and the phase change material includes high-temperature salt; The pore size of the inner layer of the porous ceramic is larger than the pore size of the surface layer of the porous ceramic; the porosity of the inner layer of the porous ceramic is larger than the porosity of the surface layer of the porous ceramic; The phase change material can enter the interior of the porous ceramic through the surface layer in a molten state; The interior provides space for storage and phase change of high temperature salt; The surface layer can prevent leakage of the phase change material in a molten state.

2. The composite phase change material according to claim 1, characterized in that: The inner lining has a porosity of 70 to 88%; Preferably, the inner lining has a porosity of 73 to 88%; more preferably, the inner lining has a porosity of 78 to 88%; and / or, the surface layer has a porosity of 50 to 75%; and / or, the loading rate of the phase change material in the matrix is ​​65 to 75 wt %; And / or, the phase change material, in liquid state, has a utilization rate of not less than 70% of the pores of the matrix; preferably, the utilization rate is not less than 75%; more preferably, the utilization rate is 85-90%; And / or, the phase change material, in solid state, has a utilization rate of not less than 60% of the pores of the matrix, preferably not less than 65%, and more preferably 70-80%.

3. The composite phase change material according to claims 1-2, characterized in that: According to the placement direction when in use, the porous ceramic has a bottom and a top; The top portion has a surface layer, and the surface layer has a thickness t1; The bottom portion has a surface layer, and the surface layer has a thickness t2; From bottom to top, the maximum thickness of the inner lining is t3; The t3 / t1 satisfies 2 to 5; and / or the t3 / t2 satisfies 2 to 5.

4. A method for preparing a composite phase change material, characterized in that: The method comprises the steps of: (a) preparing a slurry containing a first component according to the following operation, wherein the first component includes a skeleton material, a pore-forming agent, a curing agent, a sintering aid, a binder, a foaming agent, and a foam stabilizer; Wherein, the addition amount of the sintering aid can be zero; The operations include: (a.11) Prepare a solution containing a binder and stir; (a.12) contacting the foaming agent and foam stabilizer with the solution and stirring to obtain a mixed solution; (a.2) contacting the framework material, pore-forming agent, curing agent, and sintering aid with the mixed solution to obtain a slurry containing the first component; (b) preparing a slurry containing a second component; The second component includes a skeleton material, a pore-forming agent, a curing agent, a sintering aid, a binder, and a solvent; Among them, the amount of sintering aid added can be zero; (c) foaming, curing, non-sealing curing, and drying the slurry containing the first component to obtain a molded body containing the first component; stirring during the foaming process at a stirring speed of 700 to 900 rpm; (d) applying a slurry containing the second component to the surface of the molded body containing the first component and curing the slurry, repeating the process 1 to 8 times to obtain a molded body coated with the second component; (e) subjecting the molded body coated with the second component to a high-temperature sintering treatment to obtain the porous ceramic as a substrate; (f) placing the phase change material in a molten state; allowing the molten phase change material to enter the pores of the matrix; and then cooling to room temperature to obtain a composite phase change material.

5. The method for preparing a composite phase change material according to claim 1, wherein: In step (a), the solid content of the slurry containing the first component is 28 to 50 wt%; and / or, In the first component, the mass ratio of the skeleton material, the pore-forming agent, and the foaming agent is (6-7.5): (0.8-2.5): 0.06; and / or, In the first component, the mass ratio of the skeleton material, pore-forming agent, curing agent, sintering aid, binder, foaming agent and foam stabilizer is (650-800):(80-250):(80-130):(0-130):(50-70):(4-8):(1-3); and / or, In the first component, the mass ratio of the skeleton material, pore-forming agent, curing agent, sintering aid, binder, foaming agent and foam stabilizer is (650-800):(80-130):(80-130):(0-130):(50-70):(4-8):(1-3); and / or, In step (b), the solid content of the slurry containing the second component is 40 to 70 wt%; and / or, In the second component, the mass ratio of the skeleton material and the pore-forming agent is (6-9): (3-5.5) and / or, In the second component, the mass ratio of the skeleton material, pore-forming agent, curing agent, sintering aid and binder is (20-30):(10-20):(2-8):(0-8):(1-6).

6. The method for preparing a composite phase change material according to claim 4 or 5, characterized in that: In step (a.11), the stirring speed is 500 to 700 rpm; the stirring temperature is 40 to 70° C.; and / or, In step (a.12), the stirring speed is 500 to 700 rpm; the stirring temperature is 15 to 60°C.

7. The method for preparing a composite phase change material according to claim 4 or 5, characterized in that: In step (c), the sealing and curing stage lasts for 30-60 hours; and / or, The temperature of the sealing and curing stage is 15-30°C; and / or, The duration of the non-sealing curing stage is 30-60 hours; and / or, The temperature of the non-sealing curing stage is 15-30° C.; and / or, The drying time is 15-30 hours; and / or, The drying temperature is 40-80°C; and / or, The foaming time is 1-3 hours.

8. The method for preparing a composite phase change material according to claim 4 or 5, characterized in that: In step (d), the curing comprises: drying the slurry containing the second component after coating; and / or, The drying time is 5-60 minutes; and / or, The drying temperature is 60-100° C.; and / or, The operation of "coating the slurry containing the second component on the surface of the molded body containing the first component and curing" is repeated 2 to 5 times.

9. The method for preparing a composite phase change material according to claim 4 or 5, characterized in that: In step (e), the holding time of the high-temperature sintering treatment is 1-4 hours, and the holding temperature is 1000-1300°C.

10. The method for preparing a composite phase change material according to any one of claims 6 to 9, characterized in that: According to the placement direction when in use, the porous ceramic has a bottom and a top; The top portion has a molded body containing a second component, and the molded body containing the second component has a thickness t1; The bottom portion has a molded body containing a second component, and the molded body containing the second component has a thickness t2; From bottom to top, the maximum thickness of the molded body containing the first component is t3; The t3 / t1 satisfies 2 to 5; And / or, the t3 / t2 satisfies 2 to 5.

11. The method for preparing a composite phase change material according to any one of claims 6 to 9, characterized in that: In the first component, the pore former includes a porous structure pore former, or includes a non-porous structure pore former, or includes both a porous structure pore former and a non-porous structure pore former; And / or, in the second component, the pore former includes a porous structure pore former, or includes a non-porous structure pore former, or includes both a porous structure pore former and a non-porous structure pore former.

12. The porous ceramic or the method for preparing the porous ceramic according to claim 11, characterized in that: The skeleton material includes one, two or more of steel slag, blast furnace slag, fly ash, red mud, tailings, alumina, zirconium oxide, titanium oxide, silicon oxide, silicon carbide, boron carbide, silicon nitride, aluminum nitride, mullite, zircon, and cordierite; The porous structure pore-forming agent includes one, two or more of diatomaceous earth, expanded vermiculite, expanded perlite, kaolin, bentonite and quartz; The non-porous structure pore-forming agent includes one, two or more of calcium carbonate, calcite, dolomite, carbon powder, coal powder, corn starch, wheat starch and potato starch; The curing agent includes one or both of gypsum and cement; The sintering aid includes one, two or more of waste glass, sodium feldspar and potassium feldspar; The binder includes one, two or more of polyvinyl alcohol, xanthan gum, polypropylene alcohol and sodium carboxymethyl cellulose; The foaming agent includes one, two or three of sodium lauryl sulfate, sodium dodecylbenzene sulfonate and soap; The foam stabilizer includes one, two or more of dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, acrylamide, polyvinyl alcohol, cellulose and starch.

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