▎ 摘　　要

Low thermal conductivity and poor shape stability have significantly restricted the wide application of phase change materials (PCMs). In this work, a lightweight, mechanically strong, high-quality graphene aerogel was successfully prepared and used to encapsulate polyethylene glycol (PEG). After impregnating PEG into the porous graphene aerogel, a composite PCM was obtained. Owing to the preconstructed thermally conductive pathway of the graphene aerogel, the composite PCM obtained much higher thermal conductivity than neat PEG. The composite PCM also had a high latent heat of fusion and outstanding thermal cycling stability. Furthermore, the mechanically strong graphene aerogel also greatly benefited the shape stability of the composite PCM, making it capable of keeping the original shape and preventing leakage of PEG above the melting temperature. We also demonstrated that a composite PCM with such commendable comprehensive properties holds tremendous promise in fields of solar energy harvesting, thermal energy storage and thermal management.