Graphene-Based Phase Change Composite Nano-Materials for Thermal Storage Applications

We report results concerning the functionalization of graphene-based nanoplatelets for improving the thermal energy storage capacity of commonly used phase change materials (PCMs). The goal of this study was to enhance the low thermal conductivity of the PCMs, while preserving their specific and latent heats. We focused on wax-based PCMs, and we tested several types of graphene nanoparticles (GNPs) at a set of different concentrations. Both the size and shape of the GNPs were found to be important factors affecting the PCM's thermal properties. These were evaluated using differential scanning calorimetry measurements and a modified enthalpy-based water bath method. We found that a small addition of GNPs (1% weight) with high aspect ratio is sufficient to double the thermal conductivity of several widely used PCMs. Our results suggest a simple and efficient procedure for improving the thermal properties of PCMs used in thermal energy storage applications.