Ultra-high temperature graphitization of three-dimensional large-sized graphene aerogel for the encapsulation of phase change materials

Abstract

High thermal conductivity and outstanding shape stability are highly desired for the wide application of phase change materials. In this study, a large-sized graphene aerogel with a three-dimensional continuous network was fabricated by a combination of sol–gel and ultra-high temperature graphitization, and further employed to encapsulate paraffin. Benefited from the reduced contact thermal resistance and abundant thermally conductive pathway of large-flake graphene skeleton, the phase change composite shows the enhanced thermal conductivity than that of the small-sized. The phase change latent is up to 225.7 J/g, achieving high energy storage density. After the 30th thermal cycles, the phase change latent can maintain 97.11%, showing outstanding cycle stability. Meanwhile, due to the structural stability of a large-flake graphene aerogel, the original shape can be well maintained without the leakage during phase transition. This work can simultaneously solve the problems of poor thermal conductivity, low energy storage density, and paraffin leakage.