Enhancement of Thermal Performance of Composite Phase Change Materials by Graphite in Situ Modified Al2O3 Porous Support

Three-dimensionally connected, pore-adjustable, high-porosity Al2O3 foam (AF) and graphite in situ modified Al2O3 foams (GAFs) were prepared by using the particle-stabilized emulsion as a template. A graphite layer was coated on the surface of Al2O3 particles by using sucrose as a carbon resource, preventing PEG leakage and improving the thermal conductivity. After encapsulating PEG with AF and GAF, we obtained a series of stabilized composite phase change materials (sPCMs). The melting enthalpy of PGAF can reach up to 152.4, which is 27.2% higher than that of PAF. The thermal conductivity of PGAF 30 is 0.79 W/(m K), which is 1.47 times that of PEG, and the light-to-heat conversion efficiency can reach 81.31%. The prepared sPCM has broad application prospects in solar energy utilization, waste heat recovery, building energy saving, and power peak regulation.