Effective Strategies To Enhance Dehydration Kinetics in Metal Oxide Pellets for Thermal Energy Storage Materials

Thermochemical energy storage using Mg(OH)2 is attractive due to its high energy density, low cost, and nontoxicity. However, its practical application is limited by the high dehydration temperature required to achieve sufficient reaction rates. Although metal salt additives are known to enhance dehydration kinetics, prior studies have mainly focused on powders, with limited research on pellets. Unlike powders, pellet manufacturing involves high-temperature sintering for mechanical stability, requiring a specialized approach tailored to pellet fabrication. To overcome this, we present a strategy that simultaneously enhances the mechanical strength of Mg(OH)2 pellets through sintering and improves dehydration kinetics by introducing metal salts via postsintering infiltration. This method leads to an 80 °C reduction in dehydration temperature and an 8-fold increase in the maximum dehydration rate. Additionally, this study confirms that the primary factor promoting dehydration behavior is attributed to the increased active surface area and reactivity caused by the gas-liquid-solid triphasic interface formed by molten metal salt.