WO2021031976A1 - Shaped mof-based composite phase-change material, preparation method therefor and use thereof - Google Patents

Abstract

The invention relates to a shaped MOF-based composite phase-change material, a preparation method therefor and the use thereof. The preparation method involves using a formed MOF substrate as a nucleation site, and adding a ligand and metal ions, so that the disadvantage of it not being possible to easily shape a carrier when MOF is used as a phase-change material can be overcome by means of growing MOF on a foam metal. In the preparation method, a foam metal is used as a part of the shaped MOF-based composite phase-change material to enhance the thermal conductivity of the composite phase-change material. The preparation method is widely used, the raw materials are inexpensive and easily available, and the method is suitable for industrial production. The shaped MOF-based composite phase-change material comprises an MOF-based carrier and an organic phase-change core material loaded on the MOF-based carrier, wherein the MOF-based carrier comprises a foam metal and MOF, which is covered on the surface of the foam metal; by controlling the shape and size of the foam metal, the resulting shaped MOF-based composite phase-change material has the shape and size of the foam metal and a high thermal conductivity.

Description

A stereotyped MOF-based composite phase change material and its preparation method and application

cross reference

The present invention claims the priority of a Chinese patent application filed in the Chinese Patent Office with the application number 201910762614.6 and the title of the invention "a shaped MOF-based composite phase change material and its preparation method and application". The entire content of the application is incorporated by reference Incorporated in the present invention. The present invention claims the priority of a Chinese patent application filed in the Chinese Patent Office with the application number 201910762580.0 and the title of the invention "a shaped MOF-based composite phase change material and its preparation method and application". The entire content of the application is by reference Incorporated in the present invention.

Technical field

The invention relates to the field of composite phase change materials, in particular to a shaped MOF-based composite phase change material and a preparation method and application thereof.

Background technique

In the face of increasingly serious energy and environmental crises, the development of efficient energy storage and conversion technology is particularly important. Composite phase change materials have attracted more and more attention in solving energy supply and transmission, and energy conversion. In addition to traditional applications such as the use of large amounts of heat to absorb and release a large amount of heat during phase change to achieve energy input and output, composite phase change materials have also been developed in innovative applications such as photothermal conversion, electrothermal conversion, magnetothermal conversion, and hyperthermia. .

However, the phase change material has the problem of leakage during the phase change process. In order to solve the leakage problem, phase change carriers such as silica molecular sieve and kaolin are used to prepare shaped composite phase change materials. Metal organic framework (MOF), as a new type of porous organic framework, has a pivotal position in the fields of catalysis, energy storage, gas separation, etc. MOF's three-dimensional ordered interconnected structure, adjustable pore diameter, modifiable pores, and ultra-high Its porosity and large specific surface area make it an ideal carrier to support phase change materials.

However, MOF is easily powdered, difficult to form, and has low thermal conductivity, which greatly limits its application in phase change materials. Although the thermal conductivity of the composite phase change material can be improved by adding graphene, carbon nanotubes and other thermally conductive materials to the MOF, the powdery structure cannot be changed, and the cost of adding these thermally conductive materials is also high. Therefore, the problem of synthesizing a regular-shaped MOF-based composite phase change material and improving the thermal conductivity of the MOF-based composite phase change material at a low cost is in urgent need of a breakthrough.

The information disclosed in the background section is only intended to increase the understanding of the general background of the present invention, and should not be regarded as an acknowledgement or any form of suggestion that the information constitutes the prior art already known to those of ordinary skill in the art.

Summary of the invention

Purpose of invention

The purpose of the present invention is to provide a shaped MOF-based composite phase change material and its preparation method and application. The preparation method effectively overcomes the shortcomings of MOF materials that are not easy to form by growing MOF on foamed metal, and at the same time is low cost Ground improves the thermal conductivity of the MOF-based composite phase change material. The shaped MOF-based composite phase change material obtained by using the preparation method has a specified shape and high thermal conductivity.

solution

A preparation method of shaped MOF-based composite phase change material includes the following steps:

The organic ligand, soluble metal salt and if necessary additives are fully and uniformly dissolved in the solvent to obtain the MOF reaction solution; then the MOF reaction solution is reacted, and the reaction product is separated, washed, and dried to obtain the MOF matrix, and the MOF matrix Dissolve in solvent to obtain MOF mother liquor for later use;

Preheat the metal foam and maintain the temperature, use the metal foam as the substrate for MOF growth, drop the prepared MOF mother liquid to cover the surface of the foam metal, then let the solvent of the MOF mother liquid evaporate, and wash away the weakly bonded MOF with an organic solvent. Foamed metal substrate: Place the obtained foamed metal substrate in a sufficient amount of MOF growth solution with the same composition as the above-mentioned MOF reaction solution for reaction, and then wash and dry to obtain a MOF-based carrier;

The organic phase change core material is dissolved in a solvent to obtain an organic phase change core material solution, the MOF-based carrier is put into the organic phase change core material solution, and then dried to obtain the MOF-based composite phase change material.

In another possible implementation manner of the above preparation method, the foamed metal includes one or more of foamed nickel, foamed aluminum, or foamed copper; optionally, foamed copper.

In another possible implementation manner of the above preparation method, the metal foam substrate is completely covered with MOF before the metal foam matrix is placed in the MOF growth solution for reaction.

In another possible implementation of the above preparation method, the organic ligands include: terephthalic acid, phthalic acid, trimesic acid, pyromellitic acid, mellitic acid, 2-sulfonic acid Phthalic acid, 2-nitroterephthalic acid, 2-aminoterephthalic acid, 1,1':4',1"-phenyl-4,4"-dicarboxylic acid, 1,1'-diphenyl One or more of group-4,4'-dicarboxylic acid and 2-methylimidazole.

In another possible implementation manner of the above preparation method, the soluble metal salt includes: chromium nitrate, chromium chloride, chromium sulfate, chromium acetate, zirconium nitrate, zirconium chloride, zirconium sulfate, zirconium acetate, copper nitrate, and chlorine Copper, copper sulfate, copper acetate, zinc nitrate, zinc chloride, zinc sulfate, zinc acetate, nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, cobalt nitrate, cobalt chloride, cobalt sulfate, cobalt acetate, iron nitrate , Iron chloride, iron sulfate, iron acetate, aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum acetate, manganese nitrate, manganese chloride, manganese sulfate, manganese acetate, titanium nitrate, titanium chloride, titanium sulfate Or multiple.

In another possible implementation of the above preparation method, the additives include: hydrofluoric acid, sodium hydroxide, formic acid, acetic acid, benzoic acid, polyethylene oxide-polypropylene oxide-polyethylene oxide One or more of triblock copolymer, phloroglucinol/formaldehyde and triblock copolymer, triethylamine, and methanol.

In another possible implementation of the above preparation method, the organic phase change core material includes: stearyl alcohol, stearyl alcohol, stearyl acid, paraffin, polyethylene glycol, pentaerythritol, neopentyl glycol, trimethylol One or more of aminomethane and trimethylolpropane.

In another possible implementation of the above preparation method, the prepared MOF mother liquid is added dropwise to cover the surface of the foamed metal, then the solvent of the MOF mother liquid is allowed to evaporate, and the weakly bonded MOF is washed away with an organic solvent to obtain the foamed metal matrix. Including: drop the prepared MOF mother liquor to the MOF mother liquor to completely cover the surface of the foamed metal, then let the solvent of the MOF mother liquor completely evaporate, repeat the process of dropping the MOF mother liquor and the solvent evaporation several times, and then wash away the weak bond with an organic solvent MOF, then repeat the above process of dropping MOF mother liquor, solvent evaporation and organic solvent washing many times until the foam metal surface is completely covered by MOF.

In another possible implementation of the above preparation method, the mass ratio of the MOF-based carrier and the organic phase-change core material in the organic phase-change core material solution is 3-10:5; optionally, the mass ratio of the MOF-based carrier and the PEG2000 It is 4:5.

In another possible implementation of the above preparation method, when preparing the MOF mother liquor, the solvent used is water, and the molar ratio of MOF matrix to water is 1:10-40; optionally 1:20-30; further optional The ground is 1:25.

In another possible implementation of the above preparation method, the preheating temperature of the foam metal is 95-105°C.

In another possible implementation manner of the above preparation method, the reaction temperature of the MOF reaction solution is 25-100°C.

In another possible implementation manner of the above preparation method, the temperature at which the obtained foamed metal matrix is placed in the MOF growth solution for reaction is 25-100°C.

In another possible implementation of the above preparation method, the metal foam is processed before preheating for use, and the treatment includes the steps of washing and drying the metal foam to obtain a substrate on which MOF can grow; optionally, cleaning is Submerge them in acetone, methanol, and deionized water for ultrasonic cleaning.

The invention also provides the shaped MOF-based composite phase change material obtained by the above preparation method.

A shaped MOF-based composite phase change material includes a MOF-based carrier and an organic phase-change core material supported on the MOF-based carrier, wherein: the MOF-based carrier includes foamed metal and MOF covering the surface of the foamed metal.

In the above-mentioned shaped MOF-based composite phase change material, the foamed metal includes one or more of foamed nickel, foamed aluminum, or foamed copper; optionally, foamed copper.

The above-mentioned stereotyped MOF-based composite phase change material, the organic phase change core material includes: stearyl alcohol, octadecane, octadecanoic acid, paraffin, polyethylene glycol, pentaerythritol, neopentyl glycol, trimethylolaminomethane, tris One or more of hydroxymethyl propane.

In the above-mentioned shaped MOF-based composite phase change material, the MOF includes one or more of Cu-BTC, Cr-MIL-101-NH2, MOF-5, UIO-66, Al-MIL-53, and ZIF-67.

In the above-mentioned shaped MOF-based composite phase change material, in the MOF-based carrier, the surface of the foamed metal is completely covered by MOF.

The above-mentioned shaped MOF-based composite phase change material, the mass ratio of the MOF-based carrier and the organic phase-change core material in the organic phase-change core material solution is 3-10:5; optionally the mass of the MOF-based carrier and the organic phase-change core material PEG2000 The ratio is 4:5.

The application of the above-mentioned shaped MOF-based composite phase change material in energy storage and release.

Beneficial effect

1) In the present invention, a simple preparation method of shaped MOF-based composite phase change material is developed; the preparation method uses the formed MOF substrate as a nucleation site, adds ligands and metal ions, and grows MOF on the foamed metal. The method can overcome the shortcomings that MOF is not easy to shape as a phase change material carrier. By controlling the shape and size of the foam metal, the obtained MOF-based composite phase change material has the shape and size of the foam metal; the preparation method uses the foam metal as the shaping A part of the MOF-based composite phase change material is used to enhance the thermal conductivity of the composite phase change material. Because the foam metal itself has high thermal conductivity, it can also enhance the thermal conductivity of the composite phase change material; and the preparation method is applied Wide range, cheap and easily available raw materials, suitable for industrial production.

2) In the preparation method of the present invention, by selecting foamed nickel, foamed aluminum and foamed copper, the problem of low thermal conductivity of the shaped MOF-based composite phase change material can be more effectively solved; furthermore, foamed copper is compared with foamed nickel and foamed aluminum. , The cost is lower, the thermal conductivity is better, and the matrix material used for phase change materials has better heat transfer ability.

3) In the preparation method of the present invention, the content of the phase change material encapsulated by the MOF-based carrier is determined so that the encapsulated phase change core material does not leak.

4) The shaped MOF-based composite phase change material of the present invention has a specified shape, high thermal conductivity, and no leakage of the phase change core material. The foam metal is selected as the matrix, the MOF is covered on the surface of the foam metal to obtain a MOF-based carrier, and then the MOF-based carrier is used to support the organic phase change core material, and the resulting shaped MOF-based composite phase change material is controlled by the shape and size of the foam metal. The resulting shaped MOF-based composite phase change material has the shape and size of the foamed metal, and the foamed metal is used as part of the shaped MOF-based composite phase change material. Since the foamed metal itself has high thermal conductivity, it can also enhance the composite phase change material. The thermal conductivity.

Description of the drawings

Figure 1 is the differential scanning calorimetry (DSC) curve of the shaped MOF-based composite phase change material obtained in Example 1 of the present invention, in which: the upper line represents the heat release curve of the composite phase change material, and the lower line represents the composite phase change material The endothermic curve;

2 is a scanning electron microscope (SEM) image of the shaped MOF-based composite phase change material obtained in Example 1 of the present invention at a scale of 2 microns, which shows that the phase change material is successfully supported on the carrier material;

3 is a scanning electron microscope (SEM) image of the shaped MOF-based composite phase change material obtained in Example 1 of the present invention at a scale of 20 microns, which indicates that the phase change material is successfully supported on the carrier material.

detailed description

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them.的实施例。 Example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention. Unless otherwise expressly stated otherwise, throughout the specification and claims, the term "comprising" or its transformations such as "comprising" or "including" will be understood to include the stated elements or components, and not Other elements or other components are not excluded.

In addition, in order to better illustrate the present invention, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present invention can also be implemented without certain specific details. In some embodiments, raw materials, elements, methods, and means that are well known to those skilled in the art are not described in detail, so as to highlight the gist of the present invention.

In the present invention, the shape and size of the foamed metal are not particularly limited, and those skilled in the art can adjust the shape or corresponding size according to the purpose and application requirements of the present invention.

In the present invention, the pore size of the metal foam is not particularly limited, and those skilled in the art can choose the pore size of the metal foam according to the purpose and application requirements of the present invention. The description of the pore size of the foamed copper in the following examples is only an objective description of the selected foamed copper. The 500-mesh copper screen refers to the average pore size of the foamed copper of 500 mesh.

In the present invention, the role of specific additives is reflected in the preparation and growth of MOF. The preparation and growth of some MOFs require certain conditions, such as alkaline conditions (for example, by providing sodium hydroxide in Example 1) Or under acidic conditions (for example, by providing the glacial acetic acid in Example 3), but some MOFs are not required. The addition of additives and the amount of additives are determined according to the MOF to be prepared.

In the present invention, the addition ratio of the three organic ligands, soluble metal salts and specific additives is determined according to the prepared MOF.

In the present invention, the composition of the MOF reaction solution is the same as the composition of the MOF growth solution. The material value includes not only the exact same, but also the reasonable fluctuation range in the understanding of those skilled in the art, including: within ±3%, ± Within 1% or within ±0.5%.

In the present invention, a simple method can be used to determine whether the MOF growth solution is sufficient, that is, the obtained metal foam substrate is placed in the MOF growth solution for reaction. Not only does MOF grow on the foam metal substrate, but also in the MOF growth solution. There is excess MOF generated.

Implementation case 1

Cu-BTC based composite phase change material

1) Select a 500-mesh copper sieve with a volume of 2cm×2cm×1mm, and immerse the copper sieve in acetone, methanol, and deionized water for 30 minutes, and dry each time in a blast oven at 60°C to obtain a Cu-BTC growth substrate ；

2) Dissolve 7.021 g of copper nitrate and 3.063 g of trimellitic acid in a mixed solution of 25 mL of water and 25 mL of ethanol, stir vigorously at room temperature for 30 minutes to obtain a uniform solution, and then move it into the reactor. Put it in an oven at 95℃ to react for 15h. After centrifugal washing, the reaction product is placed in an oven and dried at 80℃ for 8h to obtain Cu-BTC. The dried Cu-BTC is dissolved in water to obtain Cu-BTC mother liquor. The molar ratio of the dried Cu-BTC powder to water is 1:25.

3) Preheat the copper sieve in step 1) at 100°C for 10 minutes. At this temperature, drop the Cu-BTC mother liquor prepared in step 2) onto the surface of the copper sieve until it completely covers the entire surface, and then continue to Drying at this temperature for 15 minutes to remove the solvent in the Cu-BTC mother liquor, repeat the process of three rounds of mother liquor dropping and solvent removal, and then wash the sample with ethanol and ultrasonic for 1 minute, and repeat four rounds of mother liquor dropping, solvent removal and ultrasonic washing The whole process until the surface of the copper screen is completely covered by Cu-BTC. Put the copper sieve substrate made above into a mixed solution of 25mL water and 25mL ethanol containing 7.021g copper nitrate and 3.063g trimellitic acid, transfer it into the reaction kettle and put it in an oven to react at 95℃ for 15h, then slowly Cooled to room temperature, washed, dried at 80°C for 24 hours to obtain the final Cu-BTC-based carrier for supporting the organic phase change material.

4) Dissolve 0.5g of PEG2000 in 50mL of absolute ethanol, heat and stir at 60°C until it is completely dissolved, put 0.4g of Cu-BTC-based carrier in step 3) into the above solution, and then put it in an oven at 80°C for 8h. Finally, the Cu-BTC-based composite phase change material is obtained.

The differential scanning calorimetry (DSC) curve, the scanning electron microscope (SEM) image at the 2 micron scale, and the scanning electron microscope (SEM) image at the 2 micron scale of the Cu-BTC-based composite phase change material obtained in Example 1 are shown in the figure respectively. 1- As shown in Figure 3. As shown in Figure 1, the composite phase change material releases heat at a lower temperature such as 20-40°C, and the composite phase change material absorbs heat at a higher temperature such as 50-70°C, indicating that the phase change material is successfully loaded In the carrier material. Moreover, it can be seen directly from Figures 2 to 3 that the phase change material is successfully loaded on the carrier material.

Implementation case 2

Cr-MIL-101-NH ₂ -based composite phase change material

1) Select a 500-mesh copper sieve with a volume of 2cm×2cm×1mm, and immerse the copper sieve in acetone, methanol, and deionized water for 30 minutes, and dry each time in a blast oven at 60°C to obtain Cr-MIL-101- NH ₂ growth substrate;

2) Fully dissolve 3.2g 2-aminoterephthalic acid and 3.2g nonahydrate chromium nitrate in 60mL deionized water, add 0.8g sodium hydroxide and stir vigorously for 30min at room temperature to obtain a uniform solution, then Move it into the reaction kettle and put it in an oven at 150℃ to react for 12h. After centrifugal washing, the reaction product is placed in an oven and dried at 80℃ for 8h to obtain Cr-MIL-101-NH _2. The dried Cr -MIL-101-NH _{2 is} dissolved in water to obtain Cr-MIL-101-NH ₂ mother liquor, wherein the molar ratio of the dried Cr-MIL-101-NH ₂ powder to water is 1:25.

3) Preheat the copper sieve in step 1) at 100°C for 10 minutes. At this temperature, drop the Cr-MIL-101-NH ₂ mother liquor prepared in step 2) onto the surface of the copper sieve until it completely covers the entire surface. Surface, and then continue to dry at this temperature for 15 minutes to remove _{the solvent in the Cr-MIL-101-NH 2} mother liquor, repeat the process of three rounds of mother liquor dropping and solvent removal, and then wash the sample with ethanol and ultrasound for 1 minute, and repeat four rounds The whole process of mother liquor dropping, solvent removal and ultrasonic washing until the surface of the copper sieve is completely covered by Cr-MIL-101-NH ₂ . Put the copper sieve substrate made above into 100mL uniform deionized aqueous solution containing 5.3g of 2-aminoterephthalic acid, 5.3g of chromium nitrate nonahydrate and 1.3g of sodium hydroxide, transfer it into the reactor and put it into the oven the reaction in 150 ℃ 12h, then slowly cooled to room temperature, washed, and dried 60 deg.] C 48h, to obtain Cr-MIL-101-NH ₂ group of the final support for the loaded organic phase change material.

4) The 0.5g PEG2000 was dissolved in 50mL anhydrous ethanol was heated with stirring until complete dissolution 60 ℃, in the step 3) 0.4g Cr-MIL-101 -NH 2 group carrier in the solution, and then put in an oven 80 ℃ dried 8h, to give the final Cr-MIL-101-NH ₂ group composite phase change material.

Implementation case 3

MOF-5 based composite phase change material

1) Select a 500-mesh copper sieve with a volume of 2cm×2cm×1mm, and immerse the copper sieve in acetone, methanol, and deionized water for 30 minutes, and dry in a blast oven at 60℃ each time to obtain a substrate for MOF-5 growth. ；

2) Fully dissolve 0.69g terephthalic acid and 3.41g zinc nitrate hexahydrate in 100mL DMF, stir vigorously at room temperature for 30min to obtain a uniform solution, then move it into the reactor and put it in the oven. Reacted at ℃ for 18h. After centrifugal washing, the reaction product was placed in an oven and dried at 80℃ for 8h to obtain MOF-5. The dried MOF-5 was dissolved in water to obtain MOF-5 mother liquor. The dried MOF- 5 The molar ratio of powder to water is 1:25.

3) Preheat the treated copper sieve in step 1) at 100°C for 10 minutes. At this temperature, drop the MOF-5 mother liquor prepared in step 2) onto the surface of the copper sieve until it completely covers the entire surface. Continue to dry at this temperature for 15 minutes to remove the solvent in the MOF-5 mother liquor, repeat the process of three rounds of mother liquor dropping and solvent removal, and then wash the sample with ethanol and ultrasound for 1 minute, and repeat four rounds of mother liquor dropping, solvent removal and ultrasound The whole process of washing until the surface of the copper screen is completely covered by MOF-5. Put the copper sieve substrate made above into 100mL uniform DMF solution containing 0.69g terephthalic acid and 3.41g zinc nitrate hexahydrate, transfer it into the reactor and put it in the oven at 100℃ for 18h, then slowly cool to room temperature After washing, drying at 80°C for 48h to obtain the final MOF-5 based carrier for supporting organic phase change materials.

4) Dissolve 0.5g of PEG2000 in 50mL of absolute ethanol, heat and stir at 60°C until it is completely dissolved, put 0.4g of MOF-5 based carrier in step 3) into the above solution, and then put it in an oven at 80°C for 8h. Finally, the MOF-5 based composite phase change material is obtained.

Implementation case 4

UIO-66-based composite phase change material

1) Select a 500-mesh copper sieve with a volume of 2cm×2cm×1mm, and immerse the copper sieve in acetone, methanol, and deionized water for 30 minutes, and dry each time in a blast oven at 60°C to obtain a substrate for UIO-66 growth. ；

2) Dissolve 2.85 mL of glacial acetic acid and 0.4 g of ZrCl ₄ in 75 mL of DMF, and dissolve 0.285 g of terephthalic acid in 25 mL of DMF. Stir vigorously at room temperature for 30 minutes to obtain a uniform solution. After mixing, move it into the reaction kettle, put it in an oven at 120°C for 24h. After centrifugal washing, the reaction product is placed in a vacuum drying oven at 80°C for 24h to obtain UIO-66. The dried UIO-66 is dissolved in water The UIO-66 mother liquor is obtained, wherein the molar ratio of the dried UIO-66 powder to water is 1:25.

3) Preheat the copper sieve treated in step 1) at 100°C for 10 minutes. At this temperature, drop the UIO-66 mother liquor prepared in step 2) onto the surface of the copper sieve until it completely covers the entire surface. Continue to dry at this temperature for 15 minutes to remove the solvent in the UIO-66 mother liquor, repeat the process of three rounds of mother liquor dropping and solvent removal, and then wash the sample with ethanol and sonicate for 1 minute, and repeat four rounds of mother liquor dropping, solvent removal and ultrasound The whole process of washing until the surface of the copper screen is completely covered by UIO-66. The mesh of the copper-containing substrate formed into 11.4mL of acetic acid, 1.14 g of terephthalic acid and 1.6g ZrCl 100mL of DMF ₄ uniformly, into a reaction kettle oven 24h 120 ℃ placed, then Slowly cooled to room temperature, washed, and dried at 80°C for 24 hours to obtain the final UIO-66-based carrier for supporting organic phase change materials.

4) Dissolve 0.5g PEG2000 in 50mL of absolute ethanol, heat and stir at 60°C until it is completely dissolved, put 0.4g UIO-66-based carrier in step 3) into the above solution, and then put it in an oven at 80°C for 8h. The UIO-66-based composite phase change material is finally obtained.

Implementation case 5

Al-MIL-53-based composite phase change material

1) Select a 500-mesh copper sieve with a volume of 2cm×2cm×1mm, and immerse the copper sieve in acetone, methanol, and deionized water for 30 minutes, and dry in a blast oven at 60℃ each time to obtain Al-MIL-53 growth. The base

2) Fully dissolve 0.533g of terephthalic acid and 0.787g of aluminum nitrate nonahydrate in 50mL DMF, add 0.64g of surfactant poloxamer F127 and stir vigorously for 30min at room temperature to obtain a uniform solution , Then move it into the reaction kettle, put it in an oven at 120 ℃ to react for 36 hours, the reaction product after centrifugal washing, put it in an oven at 70 ℃ for 12 hours to obtain Al-MIL-53, the dried Al- MIL-53 is dissolved in water to obtain Al-MIL-53 mother liquor, wherein the molar ratio of Al-MIL-53 powder to water after drying is 1:25.

3) Preheat the treated copper sieve in step 1) at 100°C for 10 min. At this temperature, drop the Al-MIL-53 mother liquor prepared in step 2) onto the surface of the copper sieve until it completely covers the entire surface , And then continue to dry at this temperature for 15 minutes to remove the solvent in the Al-MIL-53 mother liquor, repeat the process of three rounds of mother liquor dropping and solvent removal, and then wash the sample with ethanol and ultrasound for 1 minute, and repeat four rounds of mother liquor dropping, The entire process of removing the solvent and ultrasonic washing until the surface of the copper screen is completely covered by Al-MIL-53. Put the prepared copper sieve substrate into 100mL uniform DMF solution containing 1.28g of surfactant poloxamer F127, 1.066g of terephthalic acid and 1.574g of aluminum nitrate nonahydrate, and transfer it into the reactor React in an oven at 120°C for 36 hours, then slowly cool to room temperature, and after washing, dry at 70°C for 12 hours to obtain the final Al-MIL-53-based carrier for supporting organic phase change materials.

4) Dissolve 0.5g of PEG2000 in 50mL of absolute ethanol, heat and stir at 60°C until completely dissolved, put 0.4g of Al-MIL-53-based carrier in step 3) into the above solution, and then put it in an oven to dry at 80°C 8h, finally get Al-MIL-53 based composite phase change material.

Implementation case 6

ZIF-67-based composite phase change material

1) Select a 500-mesh copper sieve with a volume of 2cm×2cm×1mm, and immerse the copper sieve in acetone, methanol, and deionized water for 30 minutes, and dry each time in a blast oven at 60°C to obtain a substrate for ZIF-67 growth. ；

2) Fully dissolve 3.284g 2-methylimidazole and 3.321g cobalt acetate tetrahydrate in 125mL ethanol, stir vigorously at room temperature for 30min to obtain a uniform solution, then move it into the reactor and put it in the oven Reacted at 120°C for 72 hours. After centrifugal washing, the reaction product was placed in an oven and dried at 150°C for 8 hours to obtain ZIF-67. The dried ZIF-67 was dissolved in water to obtain ZIF-67 mother liquor. The dried ZIF The molar ratio of -67 powder to water is 1:25.

3) Preheat the treated copper sieve in step 1) at 100°C for 10 minutes. At this temperature, drop the ZIF-67 mother liquor prepared in step 2) onto the surface of the copper sieve until it completely covers the entire surface. Continue to dry at this temperature for 15 minutes to remove the solvent in the mother liquor of ZIF-67, repeat the process of three rounds of mother liquor dropping and solvent removal, and then wash the sample with ethanol and sonicate for 1 minute, and repeat four rounds of mother liquor dropping, solvent removal and ultrasound The whole process of washing until the surface of the copper screen is completely covered by ZIF-67. Put the copper sieve base made above into 100mL homogeneous ethanol solution containing 2.63g 2-methylimidazole and 2.66g cobalt acetate tetrahydrate, transfer it into the reaction kettle and put it in the oven for 72 hours at 120℃, and then slowly cool down To room temperature, after washing, drying at 150°C for 8 hours to obtain the final ZIF-67-based carrier for supporting organic phase change materials.

4) Dissolve 0.5g of PEG2000 in 50mL of absolute ethanol, heat and stir at 60°C until it is completely dissolved, put 0.4g of ZIF-67-based carrier in step 3) into the above solution, and then put it in an oven at 80°C for 8h. Finally, ZIF-67-based composite phase change material is obtained.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions recorded in the foregoing embodiments are modified, or some of the technical features are equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Industrial applicability

The embodiment of the present invention provides a shaped MOF-based composite phase change material and its preparation method and application. The formed MOF substrate is used as a nucleation site, ligands and metal ions are added, and MOF is grown on foam metal. It can overcome the shortcomings that MOF is not easy to form as a phase change material carrier. By controlling the shape and size of the foamed metal, the obtained MOF-based composite phase change material has the shape and size of the foamed metal; at the same time, the MOF-based composite phase change is improved at low cost. The thermal conductivity of the material.

Claims (16)

1. A preparation method of a shaped MOF-based composite phase change material is characterized in that it comprises the following steps:

   The organic ligand, soluble metal salt and if necessary additives are fully and uniformly dissolved in the solvent to obtain the MOF reaction solution; then the MOF reaction solution is reacted, and the reaction product is separated, washed, and dried to obtain the MOF matrix, and the MOF matrix Dissolve in solvent to obtain MOF mother liquor for later use;

   Preheat the metal foam and maintain the temperature, use the metal foam as the substrate for MOF growth, drop the prepared MOF mother liquid to cover the surface of the foam metal, then let the solvent of the MOF mother liquid evaporate, and wash away the weakly bonded MOF with an organic solvent Foamed metal substrate; placing the obtained foamed metal substrate in a sufficient amount of MOF growth solution with the same composition as the MOF reaction solution for reaction, and then washing and drying to obtain a MOF-based carrier;

   The organic phase change core material is dissolved in a solvent to obtain an organic phase change core material solution, the MOF-based carrier is put into the organic phase change core material solution, and then dried to obtain the MOF-based composite phase change material.
2. The preparation method according to claim 1, wherein the foamed metal includes one or more of foamed nickel, foamed aluminum, or foamed copper; optionally, foamed copper.
3. The preparation method according to claim 1, wherein the surface of the foamed metal is completely covered by MOF before the foamed metal matrix is placed in the MOF growth solution for reaction.
4. The preparation method according to claim 1, wherein the organic ligands include: terephthalic acid, phthalic acid, trimellitic acid, pyromellitic acid, mellitic acid, 2-sulfonic acid Terephthalic acid, 2-nitroterephthalic acid, 2-aminoterephthalic acid, 1,1':4',1"-phenyl-4,4"-dicarboxylic acid, 1,1'-dicarboxylic acid One or more of phenyl-4,4'-dicarboxylic acid.
5. The preparation method according to claim 1, wherein the soluble metal salt comprises: chromium nitrate, chromium chloride, chromium sulfate, chromium acetate, zirconium nitrate, zirconium chloride, zirconium sulfate, zirconium acetate, copper nitrate, Copper chloride, copper sulfate, copper acetate, zinc nitrate, zinc chloride, zinc sulfate, zinc acetate, nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, cobalt nitrate, cobalt chloride, cobalt sulfate, cobalt acetate, nitric acid One of iron, iron chloride, iron sulfate, iron acetate, aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum acetate, manganese nitrate, manganese chloride, manganese sulfate, manganese acetate, titanium nitrate, titanium chloride, and titanium sulfate Kind or more.
6. The preparation method according to claim 1, wherein the additives include: hydrofluoric acid, sodium hydroxide, formic acid, acetic acid, benzoic acid, polyethylene oxide-polypropylene oxide-polyethylene oxide One or more of alkane triblock copolymer, phloroglucinol/formaldehyde and triblock copolymer, triethylamine, methanol.
7. The preparation method according to claim 1, wherein the organic phase change core material comprises: stearyl alcohol, octadecane, stearyl acid, paraffin, polyethylene glycol, pentaerythritol, neopentyl glycol, trimethylol One or more of methylaminomethane and trimethylolpropane.
8. The preparation method according to claim 1, wherein the mass ratio of the MOF-based carrier and the organic phase-change core material in the organic phase-change core material solution is 3-10:5; optionally, the MOF-based carrier and the organic phase change The mass ratio of core material PEG2000 is 4:5;

   And/or, when preparing MOF mother liquor, the solvent used is water, and the molar ratio of MOF matrix to water is 1:10-40; optionally 1:20-30; further optionally 1:25;

   And/or, the temperature of preheating the metal foam is 95-105℃;

   And/or, the reaction temperature of the MOF reaction solution is 25-100°C;

   And/or, the temperature at which the obtained foamed metal matrix is placed in the MOF growth solution for reaction is 25-100°C.
9. A shaped MOF-based composite phase change material obtained by the preparation method according to any one of claims 1-8.
10. A shaped MOF-based composite phase change material, which is characterized in that it comprises a MOF-based carrier and an organic phase-change core material supported on the MOF-based carrier, wherein: the MOF-based carrier includes foamed metal and MOF covering the surface of the foamed metal .
11. The shaped MOF-based composite phase change material according to claim 10, wherein the foamed metal includes one or more of foamed nickel, foamed aluminum, or foamed copper; optionally, foamed copper.
12. The shaped MOF-based composite phase change material according to claim 10, wherein the organic phase change core material comprises: stearyl alcohol, octadecane, octadecanoic acid, paraffin, polyethylene glycol, pentaerythritol, neopentyl alcohol One or more of alcohol, trimethylolaminomethane, and trimethylolpropane.
13. The shaped MOF-based composite phase change material according to claim 10, wherein the surface of the foamed metal in the MOF-based carrier is completely covered by MOF.
14. The shaped MOF-based composite phase change material according to claim 10, wherein the MOF includes Cu-BTC, Cr-MIL-101-NH2, MOF-5, UIO-66, Al-MIL-53, ZIF-67 One or more of.
15. The shaped MOF-based composite phase change material according to claim 10, characterized in that: the mass ratio of the MOF-based carrier and the organic phase-change core material in the organic phase-change core material solution is 3-10:5; optionally, MOF-based The mass ratio of carrier and organic phase change core material PEG2000 is 4:5.
16. An application of the shaped MOF-based composite phase change material according to claim 9 or 10 in energy storage and release.

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