Fe3O4/carbon-decorated graphene boosts photothermal conversion and storage of phase change materials

Pristine organic phase change materials (PCMs) are difficult to complete photothermal conversion and storage. To upgrade their photothermal conversion and storage capacity, we developed Fe-MOF (metal-organic framework) derived Fe3O4/C-decorated graphene (GP) based composite PCMs toward solar energy harvesting. Graphene is an excellent phonon conductor, and Fe3O4/C-GP as a photon capturer exhibits strong full-spectrum absorption. Additionally, Fe-MOF derived Fe3O4 nanoparticles are anchored on graphene nanosheets to reduce interfacial thermal resistance, shorten thermal diffusion path, and accelerate phonon transport. After the encapsulation of octadecanol (ODA) in Fe3O4/C-GP, ODA@Fe3O4/C-GP composite PCMs yield a high photothermal conversion efficiency of 88.18 % under 0.12 W/cm2 benefiting from the synergistic effect of 3D interconnected graphene framework and Fe3O4 nanoparticles with localized surface plasmon resonance effect. Moreover, ODA@Fe3O4/C-GP composite PCMs exhibit excellent latent heat storage stability, photothermal conversion stability and durable reliability after undergoing multiple cycle evaluation, boosting high-efficiency utilization of solar energy.