Construction of hybrid graphene oxide/graphene nanoplates shell in paraffin microencapsulated phase change materials to improve thermal conductivity for thermal energy storage

Abstract

Microencapsulated phase change materials (MePCMs) are widely used for thermal energy storage. How to increase the thermal conductivity of MePCMs and maintain the maximum simultaneously is a common concern. In this work, MePCMs were prepared by encapsulating paraffin with graphene oxide (GO) in an aqueous solution through self-assembly and the hybrid shell is constructed through the π-π interaction between GO and graphene nanoplates (GNP). The result showed that ultra-thin layer structure of nano-sized GO and GNP can decrease the mass proportion of shell and improve the encapsulation rate effectively. Compare with GO shell, the hybrid shell can further enhance the thermal conductivity of MePCMs from 0.67 W/ mK to 0.90 W/ mK, while the energy storage capacity is almost the same as that of paraffin. This work proposed a simple and effective method to prepare the MePCMs with high thermal conductivity for thermal energy storage.