In this study, the influences of nano γ-Al2O3 on the thermal storage performance of LiCl were experimentally investigated. The XRD results show that a complex of lithium aluminium oxychloride (LiAlOCl2) was formed through the LiCl·H2O and γ-Al2O3 composites preparation process. The in situ diffuse reflectance infrared Fourier transform spectroscopy measurement reveals that the addition of γ-Al2O3 accelerated the hydration rate of LiCl composites, concentrated the spectrum utilization range, and promoted the desorption rate of physical adsorbed H2O and low-frequency structural -OH in the materials. The highest specific surface area of the composite is 34.5 times higher than that of pure LiCl. The addition of γ-Al2O3 can increase the conversion rate of LiCl·H2O to approximately 100% at the hydration time of 1 h and the addition content of γ-Al2O3 at 15 wt%. A maximum heat storage density (HSD) for the LiCl·H2O-γ-Al2O3 composite can reach 714.7 kJ kgLiCl·H2O-1 in 1 h when the addition content of γ-Al2O3 was 15%wt and its water uptake can reach 0.26 g g-1 in 1 h. It also can be found that the addition of Al2O3 in LiCl resulted in a decrease of the activation energy from 90.89 kJ mol-1 to 79.76 kJ mol-1. However, the thermal conductivity of the LiCl·H2O-γ-Al2O3 composite slightly decreased with the increase of nano γ-Al2O3 content.
This journal is © The Royal Society of Chemistry.