Aluminum and silicon based phase change materials for high capacity thermal energy storage

Six compositions of aluminum (Al) and silicon (Si) based materials: 87.8Al-12.2Si, 80Al-20Si, 70Al-30Si, 60Al-40Si, 45Al-40Si-15Fe, and 17Al-53Si-30Ni (atomic ratio), were investigated for potentially high thermal energy storage (TES) application from medium to high temperatures (550-1200 degrees C) through solid-liquid phase change. Thermal properties such as melting point, latent heat, specific heat, thermal diffusivity and thermal conductivity were investigated by differential scanning calorimetry and laser flash apparatus. The results reveal that the thermal storage capacity of the Al-Si materials increases with increasing Si concentration. The melting point and latent heat of 45Al-40Si-15Fe and 17A1-53Si-30Ni are similar to 869 degrees C and similar to 562 J g(-1), and similar to 1079 degrees C and similar to 960 J g(-1), respectively. The measured thermal conductivity of Al-Si binary materials depend on Si concentration and is higher than 80 W m(-1) K-1 from room temperature to 500 degrees C, which is almost two orders of magnitude higher than those of salts that are commonly used phase change material for thermal energy storage. (C) 2015 Elsevier Ltd. All rights reserved.