Preparation and thermal properties of graphite foam/eutectic salt composite as a phase change energy storage material

A graphite foam/eutectic salt composite was prepared by the infiltration of the foam by a molten binary eutectic nitrate (KNO3/NaNO3) to improve its thermal conductivity as a phase change energy storage material. The thermal properties and stability of the composite and the eutectic salt were investigated by differential scanning calorimetry and Raman spectroscopy. Results indicate that infiltration using a molten salt is an effective method to prepare the composite. The phase change temperature of the composite (221.3 degrees C) is similar to that of the salt (222.4 degrees C), and its latent heat is 3.74% lower. The composite has a thermal conductivity 102 times higher than the pure eutectic salt, because of the high thermal conductivity of the graphite. The microstructure of the composite remains unchanged after 100 phase change cycles.