Fe3O4-functionalized graphene nanosheet embedded phase change material composites: efficient magnetic- and sunlight-driven energy conversion and storage

As an important energy utilization mode, thermal energy is closely related to human life and social production. Phase change materials have been widely adopted to store thermal energy to improve its utilization efficiency. However, the inherent low energy conversion ability of these materials is one of the key problems to be resolved urgently. In this paper, we report novel magnetic- and sunlight-driven energy conversion and storage nanocomposites based on Fe3O4-functionalized graphene nanosheet (Fe3O4-GNS) embedded form-stable polymer phase change materials. Owing to the excellent magnetocaloric performance of Fe3O4 and the universal photoabsorption and photothermal conversion of graphene, the nanocomposites can effectively convert magnetic or light energy into thermal energy under an alternating magnetic field or solar illumination. The energy is stored by phase change materials during the phase transition process. The obtained hybrid nanocomposites exhibit excellent thermal stability with high melting-freezing enthalpy and excellent reversibility. Furthermore, the novel nanocomposites show the characteristics of form-stable phase transformation. The Fe3O4-GNS embedded phase change material composites for energy conversion and storage are expected to open up a rich field of energy materials.