Synthesis of Al-12Si@Porous Al2O3 macro-capsulated phase change material for high-temperature latent heat storage

Aluminum silicon (Al-Si) alloys are promising high-temperature phase change materials due to their substantial heat storage density and thermal conductivity. Encapsulating Al-Si alloys effectively addresses issues related to high-temperature leakage. In this study, Al-Si alloy powders were formed into core spheres via direct powder compaction. These cores were then encapsulated in a porous Al2O3 shell, created by blending Al2O3 powder with corn stalk powder (as a pore-forming agent) and sintered at high temperatures using the organic binder carboxymethyl cellulose sodium. The resulting macro-capsules, featuring an Al-12Si core and a porous Al2O3 shell, demonstrated a melting point of 587.76 degrees C and a latent heat of 413.03 J/g. The porous shell structure accommodates the volume expansion of the Al-Si phase change material during melting, thereby reducing the risk of leakage and rupture. Moreover, the macro-capsules maintained their shape and over 85 % of their heat storage capacity after 3000 thermal cycles, showcasing exceptional thermal storage performance. The developed Al12Si@porous Al2O3 macro-capsules, with their high latent heat capacity and durability, hold significant potential for high-temperature thermal applications.