Thermochemical heat storage system based on the sorption mechanism between water vapor and hygroscopic salts is a promising technology. However, hygroscopic salts have drawbacks such as swelling and agglomeration during hydration/dehydration cycles, which leads to decreasing specific reaction surface and heat and mass transfer problems, resulting in poor cyclic performance and stability. In this context, we propose a composite of open-cell metal foam and calcium chloride for sorption thermal energy storage. An open-cell metal foam host matrix improves the heat and mass transfer kinetics thanks to the porous structure and the high thermal conductivity. Additionally, it offers elevated mechanical strength ensuring the mechanical resistance of the composite. The composite showed significant improvement in cyclic performance compared to that of bulk salt powder. Composites exhibited a stable heat release during cycles, which improved to 5-6 times that of bulk salt powder by the 12th cycle, whereas the bulk salt degraded by 78.5%. In situ environmental scanning electron microscope observations during hydration/dehydration cycles demonstrated that swelling and deliquescence induced redistribution of salt hydrates within the metal foam while preserving essential open pores for heat and mass transfer, along with the specific reaction surface, which explains the amelioration of the composite thermochemical performance.