Abstract: A composite phase-change material (PCM) has a non-polymeric solid-solid PCM and a solid-liquid PCM. The solid-liquid PCM occupies an internal volume of the solid-solid PCM. The composite material takes full advantage of the latent heat of both PCMs, while avoiding seepage of the inner solid-liquid PCM. A method is for the preparation of the composite PCM. A thermal energy storage device includes the composite PCM.

Abstract: Composite material for storing heat energy at high temperatures (225° C. to 488° C.) formed by a porous carbon structure at least partially filled with LiOH/KOH, wherein a large amount of heat energy may be stored or released very quickly. The carbon structure is characterised by a high volumetric thermal conductivity, a low density, a highly interconnected porosity and a relatively high modulus of elasticity. The significant properties of LiOH/KOH mixtures are: a large amount of energy involved in full melting/crystallisation, a fairly low relative volume expansion upon melting and fairly low subcooling. The main advantages of the resulting composites are a very high energy density, a relatively low volume expansion, highly enhanced heat transfer, thermoadaptability, stability and insignificant hysteresis.