Preparation and Characterization of Graphene Oxide-Grafted Hexadecanol Composite Phase-Change Material for Thermal Energy Storage

With the aim of improving the shape stability and recycling reliability of hexadecanol (HD), graphene oxide (GO)-grafted hexadecanol (GO-g-HD) shape-stabilized phase-change material (SSPCM) with good thermochemical properties was prepared by oxidizing graphite powders to form GO, which was converted into the acyl chloride and finally condensed with HD. Various characterization techniques were employed to investigate the microstructure, thermal properties, thermal durability, and reliability of the composite. The results show that HD was embedded in the composite with a maximum mass fraction of 62.7 wt% through physical adsorption and covalent bonding. The grafted percentage and density of HD on ultrathin GO sheets are 36.5 wt% and 1.51 mmol g(-1) respectively. The GO-g-HD SSPCM melts at 49.7 degrees C with a latent heat of 152.3 J g(-1), and freezes at 45.4 degrees C with a phase-change enthalpy of 129.9 J g(-1). The thermal conductivity of GO-g-HD is measured as 0.519 Wm(-1) K-1, which is an improvement of 41.8% compared with that of neat HD. Moreover, the as-prepared composite also presents excellent chemical and thermal stability, excellent thermal durability, negligible variation in latent heats, and no changes in the phase-change temperatures due to strong covalent bonds and interactions between the matrix and HD. Thus, GO-g-HD is a promising candidate for thermal energy storage in the future because of the very good latent heat, enhanced conductivity, and stability.