Inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material and preparation method thereof

Abstract

The application discloses an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material and a preparation method thereof, and comprises the following steps: 1, mixing ten-water sodium sulfate / lithium nitrate composite salt, sixteen-water lithium iron manganate / calcium sulfate octahydrate composite salt, eighteen-water manganese cadmium titanate / sodium borate hexahydrate and two parts of isosorbide alpha nucleating agent to obtain a mixture A; 2, using polyethylene glycol to modify high-thermal-conductivity graphene nanoparticles; 3, preparing pitch-based carbon fiber reinforced graphene aerogel foam; 4, mixing the mixture A, the polyethylene glycol modified graphene nanoparticles and the pitch-based carbon fiber reinforced graphene foam, adding a mixture of polyethylene glycol diacrylate monomer, dipentaerythritol hexaacrylate and a photoinitiator to obtain a mixture C; and 4, irradiating the mixture C with ultraviolet light to obtain the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material, so that the supercooling degree of the hydrated salt phase change material is reduced and the phase separation of the hydrated salt phase change material is slowed down.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy storage materials, and particularly relates to an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material and a preparation method thereof. BACKGROUND

[0002] Energy storage and release by using the latent heat of phase change of phase change materials is one of effective ways to improve energy utilization efficiency. The inorganic hydrated salt phase change material has the advantages of small volume change, wide phase change temperature, high phase change enthalpy and thermal conductivity, no odor, environmental protection, safety, non-flammability, low price and wide raw material sources. However, the material has the problems of supercooling and phase separation. After a few heating-cooling cycles, solid anhydrous salt particles appear at the bottom, the middle is crystallized hydrated salt crystals, and the top is the stratification of the corresponding salt solution. With the cold and heat cycle, the heat storage capacity decreases greatly, and finally almost loses the heat storage capacity. Too large supercooling degree leads to heat release temperature fluctuation, which affects the temperature regulating effect. The phase separation appears, which causes the precipitation of the system, reduces the heat storage capacity and shortens the service life, which limits the large-scale application of the hydrated salt as an energy storage material. Therefore, reducing the supercooling degree and solving the phase separation are the most critical technical problems. SUMMARY

[0003] In view of the deficiencies in the prior art, the purpose of the present application is to provide an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material and a preparation method thereof, which reduces the supercooling degree of the inorganic hydrated salt phase change material and effectively slows down the phase separation of the inorganic hydrated salt in the phase change process.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] A preparation method of an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material, comprising the following steps:

[0006] Step 1. At 30-40 DEG C, 20-30 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 15-30 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 9.8-19.8 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate and 0.2-1 parts of dibenzyl isosorbide alpha nucleating agent are mixed according to weight parts, stirred and ultrasonically treated to obtain a mixture A of inorganic hydrated salt phase change energy storage material;

[0007] Step 2. 0.1-0.5 parts of high-thermal-conductivity graphene nanoparticles are immersed in 1-8 parts of polyethylene glycol according to weight parts, and then stirred and centrifuged in turn at 30-45 DEG C, and then dried to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0008] Step 3, mixing ethyl acetate and ethanol according to a mass ratio of 1:1 to obtain a mixed solution B, mixing pitch-based carbon fiber and the mixed solution B according to a mass ratio of 1:1, and obtaining a pitch-based carbon fiber solution after ultrasonic dispersion, then immersing graphene aerogel foam into the pitch-based carbon fiber solution according to a mass ratio of 1:10, separating out the graphene aerogel foam after ultrasonic treatment, and drying the graphene aerogel foam to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0009] Step 4, mixing 50-80 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.1-0.5 parts of polyethylene glycol modified high-thermal-conductivity graphene nanoparticles and 0.01-0.5 parts of pitch-based carbon fiber reinforced graphene aerogel foam according to weight parts at 25-35℃, stirring uniformly, then adding 10-20 parts of a mixture of phase-changeable energy storage polyethylene glycol diacrylate monomer, dipentaerythritol hexaacrylate and photoinitiator, and stirring to obtain a uniform mixture C;

[0010] Step 5, irradiating the mixture C with ultraviolet light with a wavelength of 365nm and an illumination intensity of 1-1000mW / cm 2 to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0011] Further, the stirring in step 1 is performed by a stirrer with a rotating speed of 100-1000r / min for 10-30min, and ultrasonic treatment for 10-20min.

[0012] Further, the polyethylene glycol in step 2 is polyethylene glycol with a molecular weight of 200, 400 or 600.

[0013] Further, the high-thermal-conductivity graphene nanoparticles in step 2 are 1-4-layer graphene with a particle size of 50-70nm and a thermal conductivity of 3100-3700W / m·K.

[0014] Further, the drying temperature in step 2 is 50-60℃.

[0015] Further, the pitch-based carbon fiber reinforced graphene aerogel foam in step 3 has a density of 0.1-5mg / cm 3 , a porosity of 99-99.95%, a fillable rate of 95-99%, a thermal conductivity of 200-450W / m·K, and a compressible and elastic rate of 70-85%.

[0016] Further, the mixture of the phase-changeable energy storage polyethylene glycol diacrylate monomer, dipentaerythritol hexaacrylate and the photoinitiator in step 4 comprises 5-20 parts by weight of polyethylene glycol diacrylate I, 1-3 parts by weight of polyethylene glycol diacrylate II, 1-3 parts by weight of polyethylene glycol diacrylate III, 1-3 parts by weight of dipentaerythritol hexaacrylate and 0.4-1 part by weight of the photoinitiator;

[0017] The molecular weight of the polyethylene glycol segment of the polyethylene glycol diacrylate I, the polyethylene glycol diacrylate II and the polyethylene glycol diacrylate III is 5000, 100 and 600 respectively.

[0018] Further, the photoinitiator in step 4 is one or more of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 2,4-diethylthiazolone, ethyl p-dimethylaminobenzoate or 1-hydroxycyclohexyl phenyl ketone.

[0019] Further, the irradiation time in step 3 is 15-35 min.

[0020] An inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0021] Compared with the prior art, the present application has the following technical effects:

[0022] Since the phase change temperature of the inorganic hydrated salt phase change material is moderate, mostly in the low and medium temperature range of 0-150 DEG C, and has the characteristics of high thermal conductivity and high latent heat of phase change, and has the advantages of wide source, low price, no irritating smell and stable chemical properties, the addition of the dibenzene isosorbide alpha nucleating agent can improve the defects of the inorganic hydrated salt phase change material, such as supercooling and phase separation, and the inorganic hydrated salt phase change material is combined with the matrix material (graphene aerogel foam) by using the excellent thermal conductivity and mechanical properties of graphene, the porous graphene aerogel foam is used as a porous material to absorb the phase change energy storage material, which can not only improve the thermal conductivity and mechanical properties of the phase change material, but also effectively reduce the supercooling degree of the inorganic hydrated salt phase change material, slow down the leakage problem in the phase change process, effectively prevent the phase separation of the hydrated salt phase change energy storage material, and make the crystallization more complete. Therefore, the prepared inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material has good energy storage effect and thermal conductivity, and good chemical stability, can quickly absorb and release energy, can not only be used to alleviate the contradiction between user demand and intermittent heat source supply and demand imbalance of solar energy, but also can be used for recycling industrial waste heat to realize energy management. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 : The supercooling degree curve of the composite phase change energy storage material prepared in examples 1-7 of the present application;

[0024] Figure 2 : The phase change temperature curve of the composite phase change energy storage material prepared in Embodiment 1 to Embodiment 7 of the present application;

[0025] Figure 3 : The phase change enthalpy curve of the composite phase change energy storage material prepared in Embodiment 1 to Embodiment 7 of the present application;

[0026] Figure 4 : The DSC curve of the composite phase change energy storage material prepared in Embodiment 1 to Embodiment 7 of the present application;

[0027] Figure 5 : The heat absorption / release rate curve of the composite phase change energy storage material prepared in Embodiment 1 to Embodiment 7 of the present application. DETAILED DESCRIPTION

[0028] The specific content of the present application is further explained in detail in combination with the embodiments.

[0029] The pitch-based carbon fiber reinforced graphene aerogel foam selected in Embodiment 1 to Embodiment 7 of the present application has the following characteristics: density 0.1-5 mg / cm 3 , porosity 99-99.95%, fillable rate 95-99%, three-dimensional thermal conductivity 200-450 W / m·K, and compressible resilience rate 70-85%.

[0030] The high-thermal-conductivity graphene nanoparticle selected in Embodiment 1 to Embodiment 7 of the present application has the following characteristics: thickness 1-4 layers of graphene, particle size 50-70 nm, and thermal conductivity 3100-3700 W / m·K.

[0031] The ten-water sodium sulfate / three-water lithium nitrate composite salt, sixteen-water lithium iron manganate / calcium sulfate octahydrate composite salt and eighteen-water manganese cadmium titanate / sodium borate hexahydrate selected in Embodiment 1 to Embodiment 7 of the present application are obtained by mixing two kinds of inorganic hydrated salts in a mass ratio of 1:1 and dissolving in water, and finally through a eutectic method, for example: ten-water sodium sulfate and three-water lithium nitrate are dissolved in water in a ratio of 1:1, and after cooling and crystallization, ten-water sodium sulfate / three-water lithium nitrate composite salt is obtained.

[0032] Embodiment 1

[0033] Step 1, at 30℃, 20 parts of ten-water sodium sulfate / three-water lithium nitrate composite salt, 20 parts of sixteen-water lithium iron manganate / eight-water calcium sulfate composite salt, 9.8 parts of eighteen-water manganese cadmium titanate / sodium borate hexahydrate and 0.2 parts of dibenzisosorbic acid alpha nucleating agent are mixed according to weight parts, stirred at a rotating speed of 100 r / min for 10 min, and then ultrasonically treated for 10 min, to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0034] Step 2, 0.1 parts of high thermal conductive graphene nanoparticles were immersed into 1 part of polyethylene glycol with a molecular weight of 200 according to weight parts, and then stirred by a stirrer with a rotating speed of 500 r / min for 10 min at 30℃, and then centrifuged by a centrifuge with a rotating speed of 8000 r / min for 5 min, and then dried at 50℃ to obtain polyethylene glycol modified high thermal conductive graphene nanoparticles;

[0035] Step 3, ethyl acetate and ethanol were mixed according to a mass ratio of 1:1 to obtain a mixed solution B, and then pitch-based carbon fiber was mixed with the mixed solution B according to a mass ratio of 1:1, and then ultrasonic dispersion was performed for 1 h to obtain a pitch-based carbon fiber solution, and then graphene aerogel foam was immersed into the pitch-based carbon fiber solution according to a mass ratio of 1:10, and then ultrasonic treatment was performed for 1 h, and then the graphene aerogel foam was separated out, and then dried at 60℃ for 3 h to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0036] Step 4, 55 parts of a mixture A of inorganic hydrated salt phase change energy storage materials, 0.17 parts of polyethylene glycol modified high thermal conductive graphene nanoparticles and 0.083 parts of pitch-based carbon fiber reinforced graphene aerogel foam were mixed according to weight parts at 30℃, and then stirred by a stirrer with a rotating speed of 250 r / min for 7 min, and then 5.67 parts of polyethylene glycol diacrylate I, 1.5 parts of polyethylene glycol diacrylate II, 2 parts of polyethylene glycol diacrylate III and 2 parts of dipentaerythritol hexaacrylate were added, and then 0.1 parts of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.1 parts of 2,4-diethylthiazolone, 0.2 parts of ethyl p-dimethylaminobenzoate and 0.1 parts of 1-hydroxycyclohexyl phenyl ketone were added, and then stirred by a stirrer with a rotating speed of 250 r / min for 12 min to obtain a uniform mixture C;

[0037] The molecular weight of the polyethylene glycol segment of the polyethylene glycol diacrylate I, the polyethylene glycol diacrylate II and the polyethylene glycol diacrylate III is 5000, 100 and 600 respectively;

[0038] Step 5, the mixture C was irradiated by ultraviolet light with a wavelength of 365 nm and an illumination intensity of 1 mW / cm 2 for 18 min to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0039] Example 2

[0040] Step 1, 20 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 15 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 19.8 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate and 0.2 parts of dibenzene isosorbide alpha nucleating agent were mixed according to weight parts, stirred at a rotating speed of 250 r / min for 13 min, and then ultrasonically treated for 15 min to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0041] Step 2, 0.17 parts of high-thermal-conductivity graphene nanoparticles were immersed into 2 parts of polyethylene glycol with a molecular weight of 200, and then subjected to strong stirring at a rotating speed of 920 r / min for 11 min, centrifugation at a rotating speed of 8670 r / min for 7 min, and drying at 52℃ to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0042] Step 3, ethyl acetate and ethanol were mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fiber was mixed with the mixed solution B according to a mass ratio of 1:1, and then ultrasonically dispersed for 1 h to obtain a pitch-based carbon fiber solution, and then graphene aerogel foam was immersed in the pitch-based carbon fiber solution according to a mass ratio of 1:10, ultrasonically treated for 1 h, separated out, and dried at 60℃ for 3 h to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0043] Step 4, 50 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.1 parts of high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol and 0.01 parts of pitch-based carbon fiber reinforced graphene aerogel foam were mixed according to weight parts at 25℃, stirred for 5 min by using a stirrer with a rotating speed of 100 r / min, and then 6.6 parts of polyethylene glycol diacrylate I, 1 part of polyethylene glycol diacrylate II, 1 part of polyethylene glycol diacrylate III and 1 part of dipentaerythritol hexaacrylate were added, as well as 0.1 parts of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.1 parts of 2,4-diethylthiazolone, 0.1 parts of ethyl p-dimethylaminobenzoate and 0.1 parts of 1-hydroxycyclohexyl phenyl ketone, and then stirred for 10 min by using a stirrer with a rotating speed of 100 r / min to obtain a uniform mixture C;

[0044] The molecular weight of the polyethylene glycol segment of the polyethylene glycol diacrylate I, the polyethylene glycol diacrylate II and the polyethylene glycol diacrylate III is 5000, 100 and 600 respectively;

[0045] Step 5, the mixture C was irradiated by using ultraviolet light with a wavelength of 365 nm and an illumination intensity of 100 mW / cm 2 for 15 min to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0046] Example 3

[0047] Step 1, according to the weight parts, 20 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 20 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 19.2 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate and 0.8 parts of dibenzene isosorbide alpha nucleating agent were mixed at 40℃, stirred at a speed of 400r / min for 17min, and then ultrasonic treated for 13min, to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0048] Step 2, according to the weight parts, 0.24 parts of high-thermal-conductivity graphene nanoparticles were immersed in 5 parts of polyethylene glycol with a molecular weight of 400, first stirred at a speed of 1340r / min for 12min, then centrifuged at a speed of 9340r / min for 8min, and dried at 53℃, to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0049] Step 3, ethyl acetate and ethanol were mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fiber was mixed with the mixed solution B according to a mass ratio of 1:1, ultrasonic dispersed for 1h to obtain a pitch-based carbon fiber solution, then graphene aerogel foam was immersed in the pitch-based carbon fiber solution according to a mass ratio of 1:10, ultrasonic treated for 1h, the graphene aerogel foam was separated out and dried at 60℃ for 3h, to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0050] Step 4, according to the weight parts, 60 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.24 parts of polyethylene glycol modified high-thermal-conductivity graphene nanoparticles and 0.17 parts of pitch-based carbon fiber reinforced graphene aerogel foam were mixed at 30℃, stirred by a speed of 400r / min for 8min, then 6 parts of polyethylene glycol diacrylate I, 2 parts of polyethylene glycol diacrylate II, 2 parts of polyethylene glycol diacrylate III and 3 parts of dipentaerythritol hexaacrylate were added, as well as 0.1 parts of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 0.1 parts of 2,4-diethylthiazolone and 0.2 parts of 1-hydroxycyclohexyl phenyl ketone, stirred by a speed of 400r / min for 13min, to obtain a uniform mixture C;

[0051] The molecular weight of the polyethylene glycol segment of the polyethylene glycol diacrylate I, polyethylene glycol diacrylate II and polyethylene glycol diacrylate III is 5000, 100 and 600 respectively;

[0052] Step 5, the mixture C was irradiated by a wavelength of 365nm and an illumination intensity of 334mW / cm 2The mixture C is irradiated by ultraviolet light with a wavelength of 365 nm and an illumination intensity of 500 mW / cm

[0053] Example 4

[0054] Step 1, at 45℃, 25 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 24 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 15.4 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate and 0.6 parts of dibenzene isosorbide alpha nucleating agent are mixed according to weight parts, stirred at a rotating speed of 550 r / min for 20 min, and then ultrasonic treated for 18 min, to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0055] Step 2, 0.3 parts of high-thermal-conductivity graphene nanoparticles are immersed into 6 parts of polyethylene glycol with a molecular weight of 400 according to weight parts, first stirred by a stirrer with a rotating speed of 1760 r / min for 13 min, then centrifuged by a centrifuge with a rotating speed of 10000 r / min for 9.8 min, and dried at 55℃, to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0056] Step 3, ethyl acetate and ethanol are mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fiber is mixed with the mixed solution B according to a mass ratio of 1:1, ultrasonic dispersed for 1 h to obtain a pitch-based carbon fiber solution, then graphene aerogel foam is immersed into the pitch-based carbon fiber solution according to a mass ratio of 1:10, ultrasonic treated for 1 h, separated out, and dried at 60℃ for 3 h, to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0057] Step 4, at 35℃, 65 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.31 parts of high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol and 0.25 parts of pitch-based carbon fiber reinforced graphene aerogel foam are mixed according to weight parts, stirred by a stirrer with a rotating speed of 550 r / min for 10 min, then 10 parts of polyethylene glycol diacrylate I, 1 part of polyethylene glycol diacrylate II, 1.7 parts of polyethylene glycol diacrylate III and 2 parts of dipentaerythritol hexaacrylate, as well as 0.1 parts of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide and 0.21 parts of 2,4-diethylthiazolone are added, stirred by a stirrer with a rotating speed of 550 r / min for 15 min, to obtain a uniform mixture C;

[0058] Step 5, the mixture C is irradiated by ultraviolet light with a wavelength of 365 nm and an illumination intensity of 500 mW / cm 2 , to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0059] Example 5

[0060] Step 1, at 30℃, 25 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 20.4 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 14.8 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate, and 0.6 parts of dibinary isosorbide alpha nucleating agent were mixed according to weight parts, stirred at a speed of 700r / min for 23min, and then ultrasonically treated for 20min to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0061] Step 2, 0.38 parts of high-thermal-conductivity graphene nanoparticles were immersed in 8 parts of polyethylene glycol with a molecular weight of 600, first stirred at a speed of 2180r / min for 14min, then centrifuged at a speed of 10670r / min for 11.4min, and finally dried at 56℃ to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0062] Step 3, ethyl acetate and ethanol were mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fiber was mixed with the mixed solution B according to a mass ratio of 1:1, ultrasonically dispersed for 1h to obtain a pitch-based carbon fiber solution, then graphene aerogel foam was immersed in the pitch-based carbon fiber solution according to a mass ratio of 1:10, ultrasonically treated for 1h, separated out, and dried at 60℃ for 3h to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0063] Step 4, at 30℃, 70 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.38 parts of polyethylene glycol modified high-thermal-conductivity graphene nanoparticles, and 0.33 parts of pitch-based carbon fiber reinforced graphene aerogel foam were mixed according to weight parts, stirred with a speed of 700r / min for 11min, then 10 parts of polyethylene glycol diacrylate I, 3 parts of polyethylene glycol diacrylate II, 2 parts of polyethylene glycol diacrylate III, and 1 part of dipentaerythritol hexaacrylate were added, as well as 0.68 parts of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, and stirred with a speed of 700r / min for 16min to obtain a uniform mixture C;

[0064] Step 5, the mixture C was irradiated with ultraviolet light with a wavelength of 365nm and an illumination intensity of 667mW / cm 2 for 28min to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0065] Example 6

[0066] Step 1, 30 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 25 parts of lithium iron manganate hexadecahydrate / lithium sulfate octahydrate composite salt, 17 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate, and 1 part of dibenzene isosorbide alpha nucleating agent were mixed according to weight parts at 45°C, stirred at a speed of 850 r / min for 27 min, and then ultrasonically treated for 12 min to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0067] Step 2, 0.45 parts of high-thermal-conductivity graphene nanoparticles were immersed in 4 parts of polyethylene glycol with a molecular weight of 600, and then stirred at a speed of 2600 r / min for 15 min, followed by centrifugation at a speed of 11340 r / min for 15 min, and drying at 60°C to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0068] Step 3, ethyl acetate and ethanol were mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fiber was mixed with the mixed solution B according to a mass ratio of 1:1, ultrasonic dispersion was performed for 1 h to obtain a pitch-based carbon fiber solution, and then graphene aerogel foam was immersed in the pitch-based carbon fiber solution according to a mass ratio of 1:10, ultrasonic treatment was performed for 1 h, the graphene aerogel foam was separated out, and was dried at 60°C for 3 h to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0069] Step 4, 75 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.45 parts of polyethylene glycol modified high-thermal-conductivity graphene nanoparticles, and 0.41 parts of pitch-based carbon fiber reinforced graphene aerogel foam were mixed according to weight parts at 35°C, stirred for 15 min by using a stirrer at a speed of 850 r / min, 10 parts of polyethylene glycol diacrylate I, 3 parts of polyethylene glycol diacrylate II, 3 parts of polyethylene glycol diacrylate III, and 1.35 parts of dipentaerythritol hexaacrylate were added, and 0.8 parts of 2,4-diethyl thiazolone was added, and stirred for 18 min by using a stirrer at a speed of 850 r / min to obtain a uniform mixture C;

[0070] Step 5, the mixture C was irradiated by using ultraviolet light with a wavelength of 365 nm and an illumination intensity of 850 mW / cm 2 for 33 min to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0071] Example 7

[0072] Step 1, at 30℃, 30 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 30 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 19 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate and 1 part of di-iso-sorbitol alpha nucleating agent are mixed according to weight parts, stirred at a rotating speed of 1000r / min for 30min, and then ultrasonically treated for 16min to obtain a mixture A of inorganic hydrated salt phase change energy storage materials;

[0073] Step 2, 0.5 parts of high-thermal-conductivity graphene nanoparticles are immersed into 5 parts of polyethylene glycol with a molecular weight of 400 according to weight parts, first stirred by a stirrer with a rotating speed of 3000r / min for 15min at 45℃, then centrifuged by a centrifuge with a rotating speed of 12000r / min for 15min, and dried at 54℃ to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol;

[0074] Step 3, ethyl acetate and ethanol are mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fibers are mixed with the mixed solution B according to a mass ratio of 1:1, ultrasonically dispersed for 1h to obtain a pitch-based carbon fiber solution, then graphene aerogel foam is immersed into the pitch-based carbon fiber solution according to a mass ratio of 1:10, ultrasonically treated for 1h, separated out, and dried at 60℃ for 3h to obtain pitch-based carbon fiber reinforced graphene aerogel foam;

[0075] Step 4, at 25℃, 80 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.5 parts of high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol and 0.5 parts of pitch-based carbon fiber reinforced graphene aerogel foam are mixed according to weight parts, stirred by a stirrer with a rotating speed of 1000r / min for 15min, then 10 parts of polyethylene glycol diacrylate I, 3 parts of polyethylene glycol diacrylate II, 3 parts of polyethylene glycol diacrylate III and 3 parts of dipentaerythritol hexaacrylate are added, as well as 1 part of ethyl p-dimethylaminobenzoate, stirred by a stirrer with a rotating speed of 1000r / min for 20min to obtain a uniform mixture C;

[0076] The molecular weight of the polyethylene glycol segment of the polyethylene glycol diacrylate I, the polyethylene glycol diacrylate II and the polyethylene glycol diacrylate III is 5000, 100 and 600 respectively;

[0077] Step 5, the mixture C is irradiated by ultraviolet light with a wavelength of 365nm and an illumination intensity of 1000mW / cm 2 for 35min to obtain an inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

[0078] By Figure 1It can be seen that the supercooling degrees of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention are all below 3°C.

[0079] Depend on Figure 2 It can be seen that the phase change temperature of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material prepared in Examples 1 to 7 of the present invention is between 19 and 41°C.

[0080] Depend on Figure 3 It can be seen that the phase change enthalpy values ​​of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention are all above 800 kJ / kg, and the energy storage effect is excellent.

[0081] Depend on Figure 4 It can be seen that the phase change temperature range of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention is relatively wide and is all above 8°C.

[0082] Depend on Figure 5 It can be seen that the heat absorption / release rates of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention are all above 2800 W, and can absorb and release energy relatively quickly.

[0083] The various properties of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage materials prepared in Examples 1 to 7 of the present invention are shown in Table 1.

[0084] Table 1: Properties of the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material of the present invention

[0085] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Supercooling (°C) 2.6 0.7 1.3 0.9 2.1 1.8 Longitudinal thermal conductivity (W / m-K) 423 351 503 587 386 482 Transverse thermal conductivity (W / m-K) 397 334 487 564 366 459 Energy storage efficiency (%) 95.2 94.8 92.3 97.1 93.2 91.7 Phase change temperature (°C) 40.1 32.4 24.1 38.7 19.3 21.5 Phase change enthalpy (kJ / kg) 848.64 921.52 1246.46 1354.79 1465.81 1021.85 Heat absorption / release rate (W) 2881 3249 3618 4041 4273 3557

Claims

1. A preparation method of inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material, characterized in that, The method comprises the following steps: Step 1: according to the weight parts, 20-30 parts of sodium sulfate decahydrate / lithium nitrate trihydrate composite salt, 15-30 parts of lithium iron manganate hexadecahydrate / calcium sulfate octahydrate composite salt, 9.8-19.8 parts of manganese cadmium titanate octadecahydrate / sodium borate hexahydrate, and 0.2-1 parts of dibenzene isosorbide alpha nucleating agent are mixed at 30-45 DEG C, stirred and ultrasonically treated to obtain a mixture A of inorganic hydrated salt phase change energy storage materials; Step 2: according to the weight parts, 0.1-0.5 parts of high-thermal-conductivity graphene nanoparticles are immersed in 1-8 parts of polyethylene glycol, and then stirred and centrifuged at 30-45 DEG C, and then dried to obtain high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol; Step 3: ethyl acetate and ethanol are mixed according to a mass ratio of 1:1 to obtain a mixed solution B, pitch-based carbon fiber is mixed with the mixed solution B according to a mass ratio of 1:1, and after ultrasonic dispersion, pitch-based carbon fiber solution is obtained, then graphene aerogel foam is immersed in the pitch-based carbon fiber solution according to a mass ratio of 1:10, and after ultrasonic treatment, the graphene aerogel foam is separated out and dried to obtain pitch-based carbon fiber reinforced graphene aerogel foam; Step 4: according to the weight parts, 50-80 parts of the mixture A of inorganic hydrated salt phase change energy storage materials, 0.1-0.5 parts of high-thermal-conductivity graphene nanoparticles modified by polyethylene glycol, and 0.01-0.5 parts of pitch-based carbon fiber reinforced graphene aerogel foam are mixed at 25-35 DEG C, and after being stirred uniformly, 10-20 parts of a mixture of phase-changeable energy storage polyethylene glycol diacrylate monomer, dipentaerythritol hexaacrylate, and photoinitiator are added, and after stirring, a uniform mixture C is obtained; Step 5, irradiate mixture C with UV light of wavelength 365 nm, light intensity 1-1000 mW / cm 2 to obtain inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material.

2. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The stirring in step 1 is performed by a stirrer with a rotating speed of 100-1000 r / min for 10-30 min, and ultrasonic treatment is performed for 10-20 min.

3. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The polyethylene glycol in step 2 is polyethylene glycol with a molecular weight of 200, 400, or 600.

4. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The high-thermal-conductivity graphene nanoparticles in step 2 are 1-4 layers of graphene with a particle size of 50-70 nm and a thermal conductivity of 3100-3700 W / m·K.

5. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The drying temperature in step 2 is 50-60 DEG C.

6. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The density of the pitch-based carbon fiber reinforced graphene aerogel foam in step 3 is 0.1-5 mg / cm 3 , the porosity is 99-99.95%, the fillable rate is 95-99%, the thermal conductivity is 200-450 W / m·K, and the compressive resilience is 70-85%.

7. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The mixture of phase-changeable energy storage polyethylene glycol diacrylate monomer, dipentaerythritol hexaacrylate, and photoinitiator in step 4 comprises 5-20 parts by weight of polyethylene glycol diacrylate I, 1-3 parts by weight of polyethylene glycol diacrylate II, 1-3 parts by weight of polyethylene glycol diacrylate III, 1-3 parts by weight of dipentaerythritol hexaacrylate, and 0.4-1 part of photoinitiator. The molecular weight of the polyethylene glycol segment of the polyethylene glycol diacrylate I, the polyethylene glycol diacrylate II, and the polyethylene glycol diacrylate III is 5000, 100, and 600, respectively.

8. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The photoinitiator in step 4 is one or more of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 2,4-diethylthiazolone, ethyl p-dimethylaminobenzoate, or 1-hydroxycyclohexyl phenyl ketone.

9. The method for preparing the inorganic hydrated salt / graphene aerogel foam composite phase change energy storage material according to claim 1, characterized in that: The irradiation time in step 4 is 15-35 min.

10. An inorganic hydrate salt / graphene aerogel foam composite phase change energy storage material prepared according to the method of any one of claims 1 to 9.

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