Abstract: Calcium chloride hexahydrate, possessing many advantages including suitable temperature (29 C), high enthalpy of phase change (around 191 J/g), low price and easy obtaining of raw material, security and non-toxic property, is a promising medium-low temperature phase change material in Physical energy storage. However, it suffers the typical defects of sugpercooling, phase separation and leakage, which have limited its application range. Generally, Nucleating agent and thickening agent can used to solve the problems of supercooling and phase separation. Microcapsulation and porous adsorption have the function of solving the leakage problem. Although some progresses of inhibiting defects have been achieved, further explorings of modifying properties still need to be proceeded. In this work, the major mechanisms and new study advancements of those problems are discussed. Additionally, Several study predictions are presented, including using high thermal conductivity nanoparticles and porous materials to inhibit the supercooling, utilizing high thermal conductivity thickening agents or controlling the process of crystallization to solve phase separation, finding high thermal conductivity and high strength package materials to prevent leakage, improving the technology of making porous adsorption composites to prepare surface-clean materials and achieving multiple functions with single addictive.  

Key words: phase change material, inorganic salt hydrate, calcium chloride hexahydrate, supercooling, phase separation, leakage