Self-assembly of 3D-graphite block infiltrated phase change materials with increased thermal conductivity

Expanded graphite based composite phase change materials is a good candidate for latent thermal energy storage system, while suffering large volume expansion in the phase changing process. In this work, a self-assembly method is presented to build novel 3D-graphite block, and phase change composite based on the block is prepared via casting way. The new phase change material exhibits large thermal conductivity and low volume expansion. The continuous 3D-graphite network of the carbon skeleton leads to high thermal conductivity of 15.6 W m−1·K−1 and volume expansion lower than 1%. The SEM characterization, XRD patterns, impact strength and electrical conductivity results reveal that the 3D block has network interaction and percolating threshold. Then, a new model is proposed to predict the thermal conductivity of new composite. The new phase change material has great thermal energy charging/discharging performance, which has promising application foreground as heat capacitance in thermal energy systems.