Advances in the development of latent heat storage materials based on inorganic lithium salts

Recently, inorganic thermal energy (TES) storage materials to support renewable energy implementation are being developed, and lithium salts have been showing thermal properties suitable for latent storage applications. There are three main technologies to achieve TES: sensible, latent, and thermochemical energy storage. Latent heat storage materials or phase change materials (PCMs) can store large amounts of heat per volume and they can be applied at a certain temperature, depending on the desired application. Lithium compounds for sensible storage have been reviewed in previous publications. Their use in latent heat storage applications is increasing but scarcely documented; while new latent heat storage Li materials appear consistently, the information on them is still dispersed. Therefore, the main objective of this study is to discuss lithium compounds used, proposed or analyzed for latent heat storage (LHS) and their possible applications. Lithium salts thermophysical properties, such as density, melting temperature and latent heat were tabulated as found in literature. Binary salts presented attractive heat of fusion values over 130 kJ kg(-1) in a wide range of temperatures. Moreover, the increase of stability of multi-component PCM systems due to the insertion of lithium compounds was confirmed. The technologies to produce lithium are improving and, if the demand increases, prices could decrease in the near future. Therefore, the availability of lithium materials was also analyzed in this study. Finally, potential applications of these thermal storage materials, such as heated underwater diver suits, portable thermal conditioning jackets, solar receiver space, Stirling engines, etc. were assessed.