Form-stable phase change material embedded in three-dimensional reduced graphene aerogel with large latent heat for thermal energy management

Abstract

Form-stable phase change material (PCM) composites is fabricated by vacuum-assisted melting infiltration (PEG/rGO-MI) technique, while the sample prepared by hydrothermal reduction method (PEG/rGO-HT) is also provided as control. PEG-6000 and reduced graphene oxide (rGO) are used as PCM and the porous supporting material, respectively. PEG molecules are fully filled in the connecting pore matrix of rGO aerogel with disordered arrangements for the PEG/rGO-HT sample, while distributed in the lamellar gaps of rGO nanoflakes with a regular orientation due to hydrogen bonding interactions for the PEG/rGO-MI sample. The C/O atomic ratios increase from 2.03% to 3.12% and 2.3%, respectively, for the PEG/rGO-HT and PEG/rGO-MI samples, indicating an increased sp2-hydridized C and simultaneously a decreased fraction of oxygen-containing functional groups. The Liquid leakages indicate that they both possess shape-stabilized property. The PCM mass percentage is 85.6% for the PEG/rGO-HT sample, while up to 96.6% for the PEG/rGO-MI sample. The melting latent heat of the PEG/rGO-HT sample is 139.4 J/g, whereas it is 205.2 J/g for the PEG/rGO-MI sample, much larger than that of most published works. The PEG/rGO-MI sample also exhibits excellent short-term thermal insulation property, which has promising application in complex environment for thermal energy management.