Anisotropically enhanced heat transfer properties of phase change material reinforced by graphene-wrapped carbon fibers

Abstract

Organic phase change materials (PCM, such as paraffin) are broadly used in thermal energy storage systems, especially for the efficient utilization of solar energy and industrial waste heat, whereas their low shape-stability and poor heat transfer performance have hindered the practical applications. In this work, we aim at producing high-performance phase change composites (PCCs) with high, anisotropic thermal conductivity and good shape-stability. The PCCs are supported by a biomass-derived porous carbon scaffolds, which are constructed with graphene-wrapped and vertically aligned hollow carbon fibers. The PCC with a filler content of 8.5 wt% exhibits a high lateral thermal conductivity of 1.36 W m−1 k−1 and an even higher thermal conductivity of 2.68 W m−1 K−1 along the axial fiber direction which is 10.7-fold higher than pure paraffin. The PCCs also show satisfactory shape stability, high latent heat, good thermal cycling and chemical stability. These results demonstrate the potential for fast thermal energy conversion and management using our novel carbon scaffold supported PCCs with tailored anisotropic thermal transfer properties.