阅读说明：本技术 一种仿骨头等级孔陶瓷基光热储存材料及制备方法 (Bone-like hierarchical pore ceramic-based photothermal storage material and preparation method thereof ) 是由 刘向雷 王浩蕾 宣益民 于 2020-11-27 设计创作，主要内容包括：本发明公开了一种仿骨头等级孔陶瓷基光热储存材料及其制备方法,仿照人体骨头结构采用发泡法制备了氮化铝等级孔结构,并在氮化铝骨架之上负载了一层氮化钛,最后通过真空浸渍的方法将无机盐浸入氮化铝-氮化钛骨架之中制得等级孔氮化铝陶瓷基光热储存材料。此种复合材料之中氮化铝等级孔结构形成连续的导热通道,大幅度提高了整体的热导率,热导率可达27W/m·K,极大改进了相变材料因热导率低导致的储/放热速率低的问题。负载的氮化钛使得此种复合材料可直接以太阳作为热源,氮化铝骨架快速导热,无机盐储存热量,是集吸收、传输、存储热量为一体的新型复合光热储存材料。(The invention discloses a bone-imitated hierarchical pore ceramic-based photothermal storage material and a preparation method thereof. The aluminum nitride hierarchical pore structure in the composite material forms a continuous heat conduction channel, the overall heat conductivity is greatly improved, the heat conductivity can reach 27W/m.K, and the problem of low heat storage/release rate of the phase change material caused by low heat conductivity is greatly improved. The loaded titanium nitride enables the composite material to directly use the sun as a heat source, the aluminum nitride framework conducts heat rapidly, and the inorganic salt stores heat, so that the composite material is a novel composite photo-thermal storage material integrating absorption, transmission and heat storage.)

1. The bone-imitated hierarchical-pore ceramic-based photothermal storage material is characterized by comprising the following components in percentage by mass: the inorganic salt phase change material accounts for 41.8-46.4% by mass, the photo-thermal material accounts for 1-3% by mass, and the heat conduction reinforcing material accounts for 50.6-57.2% by mass.

2. The bone-like hierarchical pore ceramic-based photothermal storage material of claim 1, wherein the inorganic salt phase change material is prepared by mixing lithium nitrate and chloride salt or carbonate according to a ratio of 90: 5-90: 10.

3. The bone-like hierarchical pore ceramic-based photothermal storage material of claim 2, wherein the mixed eutectic is NaCl and LiNO₃And mixing the eutectic.

4. The bone-like hierarchical pore ceramic-based photothermal storage material of claim 1, wherein the photothermal material is titanium nitride, and the particle size is 50nm to 2 μm.

5. The bone-like graded-hole ceramic-based photothermal storage material of claim 1, wherein the thermal conductivity enhancing material is a ceramic material with a thermal conductivity of more than 200W/m-K, and the ceramic material is silicon carbide, aluminum nitride, boron nitride or silicon dioxide.

6. The preparation method of the bone-like graded-pore ceramic-based photothermal storage material according to any one of claims 1 to 5, comprising the following steps:

1) because the hydrolysis characteristic of the aluminum nitride can affect the heat-conducting property, the aluminum nitride needs to be subjected to hydration resistance treatment before being used;

2) weighing the treated aluminum nitride powder, Ib-104 (amide-ammonium salt copolymer) and water according to the raw material proportion, and uniformly mixing;

3) adding foaming agents with different amounts into the prepared slurry, mechanically stirring and foaming, pouring into a mold, and naturally drying for two days to prepare a hierarchical pore aluminum nitride framework precursor;

4) placing the prepared framework precursor in a muffle furnace for glue removal treatment to prepare a framework green body;

5) placing the prepared skeleton green blank in a hot pressing furnace, and heating and sintering to obtain a graded-hole aluminum nitride skeleton;

6) placing the prepared aluminum nitride framework in a mixed solution of titanium nitride and ethanol, repeatedly soaking, placing in a forced air drying oven for drying, and then placing in a muffle furnace for firing to obtain a graded-pore aluminum nitride-titanium nitride framework;

7) and dipping the prepared aluminum nitride-titanium nitride framework in an inorganic salt phase-change material to obtain the graded-pore ceramic-based photo-thermal storage material.

7. The method for preparing the bone-like graded-pore ceramic-based photothermal storage material according to claim 6, wherein the hydration-resistant treatment in step 1) is performed by reacting polyurethane and tetraethylenepentamine to form a water-resistant film to wrap the water-resistant film on the aluminum nitride powder, and the components in step 2) are mixed by ball milling.

8. The preparation method of the bone-like graded-pore ceramic-based photothermal storage material as claimed in claim 6, wherein the foaming agent in step 3) is triethanolamine dodecyl sulfate, the content of the foaming agent is 0.55-0.75% by mass, the skeleton precursor glue removal treatment in step 4) is performed in air, the heating temperature is 650-800 ℃, the heating rate is 1 ℃/min, and the heat preservation time is 4 h.

9. The method for preparing the bone-like graded-pore ceramic-based photothermal storage material according to claim 6, wherein the heating of the skeleton green body in step 5) is performed in an inert gas, and the inert gas is one of nitrogen, argon and helium;

the heating temperature of the skeleton green blank is 1950 ℃, and the heat preservation time is 4 hours;

the sintering agent used for heating and sintering the skeleton green blank is yttrium oxide, aluminum oxide, lanthanum oxide, yttrium fluoride and calcium fluoride.

10. The method for preparing the bone-like graded-pore ceramic-based photothermal storage material according to claim 6, wherein the concentration ratio of titanium nitride to ethanol in step 6) is 1:100, 2:100, 3:100, 4:100 or 5:100;

the repeated dipping times are 3-4 times, the drying temperature of the air blowing drying box is set to be 80-100 ℃, the temperature of the muffle furnace is set to be 300 ℃, the heat preservation time is 1h, and the dipping method in the step 7) is vacuum dipping.

Technical Field

The invention relates to the technical field of energy storage material production by a chemical and chemical method and the scientific and technical field of energy materials, in particular to a bone-like hierarchical pore ceramic-based photothermal storage material and a preparation method thereof.

Background

Energy is used as a support for economic development, and with the continuous consumption of society progress, the search for new alternative energy is particularly important. Solar energy is taken as a great important source of earth resources, and the solar energy is long in supply, clean, safe and rich in storage capacity, so that the solar energy is favored by extensive researchers for development and application. However, the solar radiation energy density and radiation intensity are limited by natural conditions such as seasons, day and night, cloudy and sunny conditions, and the like, so that great instability and intermittence exist, and therefore, the development of a thermal energy storage technology is urgently needed to relieve the mismatching of the supply and the demand of thermal energy in time, space and intensity, improve the energy utilization rate, reduce the energy utilization cost and effectively improve the flexibility of energy utilization.

Sensible heat energy storage is the most common heat storage mode at present, requires large volume and is mainly used for storing heat energy with lower temperature, generally lower than 150 ℃ for heating; thermochemical heat storage achieves the purpose of heat absorption and release by utilizing chemical reaction, and reaction equipment is precise and complex because of the chemical reaction, so that the thermochemical heat storage is generally suitable for a larger system; the latent heat of phase change energy storage utilizes the phase change characteristic of a substance, and the latent heat absorbed or released when the temperature reaches a phase change point has the characteristics of high heat storage density, isothermal heat absorption and release process and the like, so that the phase change material is highly valued by people and widely applied to various energy storage systems, such as concentrated solar power generation (CSP), industrial waste heat recovery, electronic device cooling, medical drug transportation and aviation and aerospace heat protection.

The core of the phase change energy storage technology is the phase change material, and the latent heat and the heat transfer of the phase change material directly influence the efficiency and the power of an energy storage system. Inorganic salt is the first choice of medium-high temperature phase change heat storage materials, but faces many challenges in practical application, pure inorganic salt has low thermal conductivity and is not beneficial to heat charging and discharging of an energy storage system, and when the sun is used as a heat source, energy cannot be rapidly collected when solar radiation energy density is the highest. At present, the commonly used technical means is to add high thermal conductive filler such as graphene and carbon nanotube in the phase change material, or to inject the phase change material into a porous structure such as foam metal. However, inorganic salts are highly corrosive and are not favorable for use in carbon-based and metal materials, and thus, corrosion-resistant ceramics are used as a base material.

When solar energy is used as a heat source, a common surface type heat storage system has high surface temperature, a plurality of internal heat transfer links and too large thermal resistance, so that the heat transfer is too slow, the surface heat cannot be transferred to a heat storage material in time, most heat is dissipated, and finally the efficiency is low.

The inorganic salt has leakage problem during solid-liquid conversion, so that the inorganic salt can be prevented from leaking by adopting a packaging mode, but the thermal resistance between the heat transfer medium and the phase change material is increased, and the heat transfer efficiency is reduced.

Therefore, the difficulty in developing the heat storage technology at present is how to reduce the intermediate thermal resistance, improve the heat transfer rate, increase the heat storage and release rate of the system, reduce the heat loss and simultaneously improve the heat storage density. Therefore, the development of the composite photo-thermal material integrating light-heat conversion, heat transfer and storage is very significant.

Disclosure of Invention

Aiming at the defects of the prior heat storage technology, the invention provides a bone-like hierarchical pore aluminum nitride ceramic-based photothermal storage material and a preparation method thereof.

The bone-like graded-hole aluminum nitride ceramic-based photo-thermal storage material comprises an inorganic salt phase-change heat storage material, a photo-thermal material and a heat conduction reinforcing material, wherein the mass ratio of the inorganic salt phase-change material is 41.8-46.4%, the mass ratio of the photo-thermal material is 1-3%, and the mass ratio of the heat conduction reinforcing material is 50.6-57.2%.

Further, the inorganic salt phase change material is prepared by mixing lithium nitrate and chloride salt or carbonate according to a certain proportion, and is preferably mixed eutectic of NaCl and LiNO 3; the bone-imitated hierarchical pore ceramic-based photothermal storage material is characterized in that the photothermal material is titanium nitride, and the particle size is 50 nanometers; the heat conduction strengthening material is a ceramic material with high heat conductivity, such as silicon carbide, aluminum nitride, boron nitride, silicon dioxide and the like, preferably aluminum nitride, has the theoretical heat conductivity of 320W/m.K, and has the characteristics of high temperature resistance and corrosion resistance.

The invention provides a preparation method of a bone-like hierarchical pore ceramic-based photothermal storage material, which comprises the following steps:

step 1, because the hydrolysis characteristic of the aluminum nitride can influence the heat-conducting property, the aluminum nitride needs to be subjected to hydration resistance treatment before being used;

step 2, weighing the treated aluminum nitride powder, Ib-104 (amide-ammonium salt copolymer) and water according to the raw material proportion, and uniformly mixing;

step 3, adding foaming agents with different amounts into the prepared slurry, mechanically stirring and foaming, pouring into a mold, and naturally drying for two days to prepare a hierarchical-pore aluminum nitride framework precursor;

step 4, placing the prepared framework precursor in a muffle furnace for glue removal treatment to prepare a framework green body;

step 5, placing the prepared skeleton green blank in a hot pressing furnace, and heating and sintering to obtain a graded-hole aluminum nitride skeleton;

and 6, placing the prepared aluminum nitride framework into a mixed solution of titanium nitride and ethanol, repeatedly soaking, placing into a forced air drying oven for drying, and then placing into a muffle furnace for firing to obtain the hierarchical porous aluminum nitride-titanium nitride framework.

And 7, dipping the prepared aluminum nitride-titanium nitride framework in an inorganic salt phase-change material to obtain the graded-pore ceramic-based photo-thermal storage material.

Furthermore, the hydration-resistant treatment mode in the step 1 is to use polyurethane and tetraethylenepentamine to react to generate a layer of water-resistant film to wrap the aluminum nitride powder.

Further, the mixing of the components in step 2 is preferably ball milling.

Further, the foaming agent in the step 3 is lauryl triethanolamine sulfate, and the content of the foaming agent is 0.55-0.75% by mass.

Further, the skeleton precursor glue removing treatment in the step 4 is carried out in the air, the heating temperature is 650-800 ℃, the heating rate is 1 ℃/min, and the heat preservation time is 4 h.

Further, the heating of the skeleton green body in the step 5 is performed in an inert gas, wherein the inert gas atmosphere is preferably one of nitrogen, argon and helium, and particularly preferably nitrogen;

further, in step 5, the heating temperature of the raw skeleton embryo is 1950 ℃, and the holding time is 4 h.

Preferably, the sintering agent used for heating and sintering the skeleton green blank in the step 5 is yttrium oxide, aluminum oxide, lanthanum oxide, yttrium fluoride and calcium fluoride, particularly preferably yttrium oxide, and is mixed with aluminum nitride powder in the step 1.

Further, the concentration of titanium nitride and ethanol in step 6 is preferably 1:100, 2:100, 3:100, 4:100, 5:100, and particularly preferably 1:100;

preferably, the repeated dipping times in the step 6 are 3-4 times;

preferably, the drying temperature of the air drying oven in the step 6 is set to be 80-100 ℃;

preferably, in the step 6, the set temperature of the muffle furnace is 300 ℃, and the holding time is 1 h.

Further, the impregnation method described in step 7 is preferably vacuum impregnation.

According to the invention, the porous three-dimensional structure of the bone is simulated, the porous three-dimensional structure is prepared by using aluminum nitride, titanium nitride particles are added on the surface of the framework and compounded with the intermediate-temperature inorganic phase-change material, the thermal conductivity of the composite material is improved, the spectral absorption rate of the composite material is greatly improved, the sun can be directly used as a heat source, the aluminum nitride framework rapidly conducts heat after light absorption, and the phase-change material stores heat.

The medium-temperature photo-thermal storage material provided by the invention means that the use temperature of the heat storage material can reach 220 ℃.

Compared with the prior art, the invention has the following remarkable advantages:

1. the aluminum nitride is used as a heat-conducting base material, the aluminum nitride is stable in performance, high-temperature resistant and corrosion resistant, the problems of corrosion of molten salt to a metal base material and high-temperature oxidation of a carbon-based base material are solved, and the heat conductivity can reach 27W/m.K.

2. The invention adopts a porous structure, improves the overall thermal conductivity of the composite material, and simultaneously improves the problem of leakage of the phase-change material during solid-liquid change.

3. According to the invention, titanium nitride is loaded on the aluminum nitride framework, so that the spectral absorption rate is greatly improved and can reach 98%, and the solar heat can be absorbed as a heat source and transferred to the phase-change material for storage in time under the high-heat-conductivity framework.

When the porosity of the framework is 70%, the energy storage density of the medium-temperature photo-thermal storage material can reach 495J/g at the temperature difference of 200 ℃.

Drawings

FIG. 1 is a graph showing the pH of suspensions of the treated aluminum nitride powder and the untreated powder in accordance with the effect of the anti-hydration treatment in example 1;

FIG. 2 is a characteristic XRD pattern of a dried powder of an untreated powder suspension for anti-hydration effect in example 1;

FIG. 3 is a characteristic XRD pattern of a dried powder of the treatment powder suspension for anti-hydration treatment effect in example 1;

FIG. 4 is a thermogram of LiNO3-NaCl eutectic salt synthesized in example 1;

FIG. 5 is an SEM image of the structure of the synthetic bone-like graded pore aluminum nitride of example 1;

FIG. 6 is a spectrum of the bone-like graded porous aluminum nitride-titanium nitride composite phase change material and aluminum nitride skeleton synthesized in example 1;

FIG. 7 is a graph of thermal conductivity as a function of porosity for the bone-like grade pore aluminum nitride synthesized in example 1.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described below by way of examples. It should be understood by those skilled in the art that the examples are only for the purpose of facilitating understanding of the present invention and should not be construed as specifically limiting the present invention.

Example 1:

taking the mass ratio of 100: 3: 75 g of 1-micron aluminum nitride powder, 1.05g of yttrium oxide and 26.25g of absolute ethyl alcohol are respectively placed in a ball mill at the rotating speed of 270rpm for half an hour; then adding 0.2wt% of ethanol dispersant polyacrylic acid, and continuing to ball-mill for half an hour at the rotating speed of 270 rpm; then adding 1wt% of polyurethane, and ball-milling at the rotating speed of 270rpm for half an hour; finally, adding tetraethylenepentamine, mechanically stirring to enable the tetraethylenepentamine to react with polyurethane to generate a water-resistant film, and wrapping the water-resistant film on the aluminum nitride powder.

Then the mixture is put into an oven for drying to prepare the hydration-resistant aluminum nitride powder. Weighing the treated aluminum nitride powder and water according to the mass ratio of 73 percent, weighing 0.3 weight percent of Ib-104 (used as a gelling agent and a dispersing agent) to be mixed with the aluminum nitride powder and the water, and placing the mixture into a ball mill to be ball-milled for half an hour at 270 rpm.

Taking out the slurry after ball milling, weighing a foaming agent (triethanolamine lauryl sulfate) which is 0.65wt% of the slurry taken out, pouring the foaming agent into the slurry, and mechanically stirring for foaming for half an hour at 700 rpm. Pouring the foamed porous slurry into a mold, taking out the porous slurry from the mold after the porous slurry is molded, naturally drying the porous slurry for two days, placing the porous slurry in a muffle furnace air atmosphere, heating the porous slurry to 650 ℃ at the heating rate of 1 ℃/min, and completely removing the hydration-resistant agent.

And then placing the skeleton green body in a hot pressing furnace in nitrogen atmosphere, heating to 1950 ℃, sintering and preserving heat for 4 hours to obtain a high-heat-conductivity aluminum nitride hierarchical pore structure with good strength and hardness, wherein the thermal conductivity is 25.182W/m.K when the porosity is 70% measured by a laser heat conduction method. Preparing a mixed solution with the mass ratio of titanium nitride to ethanol being 1:100, soaking the prepared aluminum nitride framework in the mixed solution of titanium nitride and ethanol for 5 minutes, placing the soaked aluminum nitride framework in a blast oven for drying at 100 ℃ for 20 minutes, soaking and drying the aluminum nitride framework back and forth for three times, and placing the aluminum nitride framework in a muffle furnace for firing for one hour at 300 ℃.

The aluminum nitride-titanium nitride framework with high thermal conductivity and high spectral absorption is successfully prepared, the thermal conductivity is 24.657W/m.K, and the spectral absorption rate is 98%. Weighing LiNO3 and NaCl in a mass ratio of 93.6:6.4, ball-milling for 2 hours, uniformly mixing, placing in a muffle furnace, heating to 350 ℃ at a heating rate of 5 ℃/min, and preserving heat for 1 hour to obtain the LiNO3-NaCl eutectic salt.

Mixing the aluminum nitride-titanium nitride skeleton and LiNO₃And (3) putting the NaCl eutectic salt into a tube furnace, heating to 300 ℃, vacuumizing and dipping for 4 hours to prepare the bone-like grade hole aluminum nitride-based high-heat-conduction medium-temperature photo-thermal storage material, wherein the thermal conductivity of the compound is 24.931W/m.K, the spectral absorption rate reaches 92%, and the energy storage density reaches 495J/g.

Example 2:

taking the mass ratio of 100: 3: 75 g of aluminum nitride powder with the particle size of 2 mu m, 1.05g of yttrium oxide and 26.25g of absolute ethyl alcohol are respectively placed in a ball mill at the rotating speed of 270rpm for half an hour; then adding 0.2wt% of ethanol dispersant polyacrylic acid, and continuing to ball-mill for half an hour at the rotating speed of 270 rpm; then 1wt% of polyurethane was added and ball milled at 270rpm for half an hour.

Finally, adding tetraethylenepentamine, mechanically stirring to enable the tetraethylenepentamine to react with polyurethane to generate a water-resistant film, and wrapping the water-resistant film on the aluminum nitride powder. Then the mixture is put into an oven for drying to prepare the hydration-resistant aluminum nitride powder. Weighing the treated aluminum nitride powder and water according to the mass ratio of 73 percent, weighing 0.3 weight percent of Ib-104 (used as a gelling agent and a dispersing agent) to be mixed with the aluminum nitride powder and the water, and placing the mixture into a ball mill to be ball-milled for half an hour at 270 rpm. Taking out the slurry after ball milling, weighing a foaming agent (triethanolamine lauryl sulfate) which is 0.65wt% of the slurry taken out, pouring the foaming agent into the slurry, and mechanically stirring for foaming for half an hour at 700 rpm. Pouring the foamed porous slurry into a mold, taking out the porous slurry from the mold after the porous slurry is molded, naturally drying the porous slurry for two days, placing the porous slurry in a muffle furnace air atmosphere, heating the porous slurry to 650 ℃ at the heating rate of 1 ℃/min, and completely removing the hydration-resistant agent. And then placing the skeleton green body in a hot pressing furnace in nitrogen atmosphere, heating to 1950 ℃, sintering and preserving heat for 4 hours to obtain the high-heat-conductivity aluminum nitride hierarchical pore structure with good strength and hardness. Preparing a mixed solution with the mass ratio of titanium nitride to ethanol being 1:100, soaking the prepared aluminum nitride framework in the mixed solution of titanium nitride and ethanol for 5 minutes, placing the soaked aluminum nitride framework in a blast oven for drying at 100 ℃ for 20 minutes, soaking and drying the aluminum nitride framework back and forth for three times, and placing the aluminum nitride framework in a muffle furnace for firing for one hour at 300 ℃.

And finally, successfully preparing the aluminum nitride-titanium nitride framework with high thermal conductivity and high spectral absorption. Weighing LiNO3 and Li2CO3 in a mass ratio of 90:10, ball-milling for 2 hours, uniformly mixing, placing in a muffle furnace, heating to 350 ℃ at a heating rate of 5 ℃/min, and preserving heat for 1 hour to obtain LiNO3-Li2CO3 eutectic salt. And putting the aluminum nitride-titanium nitride framework and LiNO3-Li2CO3 eutectic salt into a tubular furnace, heating to 300 ℃, vacuumizing and dipping for 4 hours to obtain the bone-like hierarchical porous aluminum nitride-based high-heat-conductivity medium-temperature photo-thermal storage material.

Example 3:

taking the mass ratio of 100: 3: 75 g of silicon carbide powder with the particle size of 1 mu m, 1.05g of yttrium oxide and 26.25g of absolute ethyl alcohol are respectively placed in a ball mill at the rotating speed of 270rpm, the silicon carbide powder and water are weighed according to the mass ratio of 70 percent, 0.3 weight percent of Ib-104 (used as a gelling agent and a dispersing agent) is weighed, mixed with the silicon carbide powder and the water, and the mixture is placed in the ball mill for ball milling for half an hour at the rotating speed of 270 rpm. Taking out the slurry after ball milling, weighing a foaming agent (triethanolamine lauryl sulfate) which is 0.65wt% of the slurry taken out, pouring the foaming agent into the slurry, and mechanically stirring for foaming for half an hour at 700 rpm. Pouring the foamed porous slurry into a mold, taking out the porous slurry from the mold after the porous slurry is molded, naturally drying the porous slurry for two days, placing the porous slurry in a muffle furnace air atmosphere, heating the porous slurry to 650 ℃ at the heating rate of 1 ℃/min, and completely removing Ib-104. And then placing the skeleton green body in a hot pressing furnace in nitrogen atmosphere, heating to 1950 ℃, sintering and preserving heat for 4 hours to obtain the high-thermal-conductivity silicon carbide hierarchical pore structure with good strength and hardness. Preparing a mixed solution with the mass ratio of titanium nitride to ethanol being 1:100, soaking the prepared aluminum nitride framework in the mixed solution of titanium nitride and ethanol for 5 minutes, placing the soaked aluminum nitride framework in a blast oven for drying at 100 ℃ for 20 minutes, soaking and drying the aluminum nitride framework back and forth for three times, and placing the aluminum nitride framework in a muffle furnace for firing for one hour at 300 ℃. The silicon carbide-titanium nitride framework with high thermal conductivity and high spectral absorption is successfully prepared. Weighing LiNO3 and Li2CO3 in a mass ratio of 90:10, ball-milling for 2 hours, uniformly mixing, placing in a muffle furnace, heating to 350 ℃ at a heating rate of 5 ℃/min, and preserving heat for 1 hour to obtain LiNO3-Li2CO3 eutectic salt. And putting the aluminum nitride-titanium nitride skeleton and LiNO3-Li2CO3 eutectic salt into a tubular furnace, heating to 300 ℃, vacuumizing and dipping for 4 hours to obtain the bone-like hierarchical-hole silicon carbide-based high-heat-conduction medium-temperature photo-thermal storage material.

As shown in test tests, the bone-like graded-hole aluminum nitride ceramic-based photothermal storage material prepared in the embodiments 1-3 adopts aluminum nitride as a heat-conducting base material, has stable performance, high temperature resistance and corrosion resistance, solves the problems of corrosion of molten salt to a metal base material and high-temperature oxidation of a carbon-based base material, and has a thermal conductivity of 27W/m.K. (ii) a And a porous structure is adopted, so that the overall thermal conductivity of the composite material is improved, and the problem of leakage of the phase-change material during solid-liquid change is solved.

In addition, the titanium nitride is loaded on the aluminum nitride framework, the spectral absorption rate is greatly improved and can reach 98%, and the solar heat source can absorb heat and transfer the heat to the phase-change material for storage under the high-heat-conductivity framework in time. Wherein, when the porosity of the skeleton is 70%, the energy storage density of the thermo-optic thermal storage material can reach 495J/g at the temperature difference of 200 ℃.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.