Design and Preparation of the Phase Change Materials Paraffin/Porous Al₂O₃@Graphite Foams with Enhanced Heat Storage Capacity and Thermal Conductivity

Abstract

Porous Al2O3@graphite foams (PAGFs) were directly prepared by a particle-stabilized foaming method, with 40 vol % Al2O3 particles and different proportions of sucrose. The as-prepared PAGFs demonstrate three-dimensional interpenetrating structures and high porosities according to SEM images, with the porous morphology being markedly influenced by the concentration percentage of sucrose. Additionally, the PAGFs could be successfully impregnated with paraffin, reaching a maximum enclosed ratio (φ) of 66 wt % without any leakage. Differential scanning calorimetry measurement showed that the latent heat of the composites of paraffin/PAGF (PAGFPs) reach maxima of 105.76 and 105.98 J/g after 200 cycles of melting/freezing. Thermogravimetric analysis, Fourier transform infrared spectroscopy, and thermal cyclic tests demonstrated good thermal and chemical stability and good thermal reliability for the as-prepared form-stable PAGFPs. Our results also confirmed that a layer of ordered graphite film is formed on the surface of Al2O3 particles after sintering at 1600 °C. As a result, the specific surface area of PAGF is 13 times greater than that of the foams without coating graphite. Meanwhile, the thermal conductivities of the PAGFPs reached a maximum of 0.76W/m·K, which was 3.62 times that of pristine paraffin. In conclusion, we demonstrated here the design and preparation of form-stable composite phase change materials with controllable porous structures and superior thermal and chemical stabilities and reliabilities for heat energy storage applications.

Smart Utilization of Multifunctional Metal Oxides in Phase Change Materials

“…The thermal conductivity of composite PCMs containing 10 wt % Al 2 O 3 @EG is 4.5 times that of pure 1-octadecanol due to the synergy enhancement of Al 2 O 3 and EG, and the phase change enthalpy is approximately 200 J/g. Similarly, Li et al 70 prepared porous Al 2 O 3 @graphite foams (PAGFs) with a high porosity using a particle-stabilized foaming method. The average diameter of PAGF is increased from approximately 80 to 250 mm.…”

Silica-Based Core-Shell Nanocapsules: A Facile Route to Functional Textile

“…However, the disadvantages of polymeric shells, such as poor stability, biological safety and flammability limited applications [19]. Therefore, inorganic shell materials, such as CaCO 3 [20], TiO 2 [21], Al 2 O 3 [22] and SiO 2 [23], have attracted attention because of a number of useful features. Especially, silica materials are particularly noteworthy due to their availability, low cost, good thermal conductivity, chemical inertness, excellent stability and mechanical strength, and biocompatibility [24].…”

Expanded Graphite/Paraffin/Silicone Rubber as High Temperature Form-stabilized Phase Change Materials for Thermal Energy Storage and Thermal Interface Materials

“…However, the drawback of PW is low thermal conductivity and the possibility of liquid leakage during the phase change process, which restricts its broad applications [6,7]. In order to increase its thermal conductivity, several thermally conductive fillers, such as ceramic fillers Al 2 O 3 [8,9], AlN [10] and metal nanoparticles Cu [11], Al [12] and Ag [13], were added into PW. For its liquid leakage issue, there are two approaches have been employed.…”