Patent ID: 8091613

Claim:
A thermal energy storage material system that reproducibly stores and recovers latent heat comprising: a. a container having a wall surface; and b. a thermal energy storage material in at least partial contact with the wall surface, and including: i) at least one first metal containing material including at least one first metal compound that includes a nitrate ion, a nitrite ion, or both; and ii) at least one second metal containing material including at least one second metal compound; wherein the thermal energy storage material is free of water or includes less than 10 wt. % of water; wherein the thermal energy storage material has a liquidus temperature, T L , from about 100° C. to about 250° C.; and wherein the thermal energy storage material exhibits a heat storage density from 300° C. to 80° C. of at least 1 MJ/l; so that upon being used in a system that generates heat, at least a portion of the heat is captured and stored by the thermal energy storage material and subsequently released for use; wherein the thermal energy storage material is encapsulated in a plurality of capsules each having a volume of less than 200 ml, the thermal energy storage material includes lithium cations, and wherein the absolute value of the change in mass of the wall surface in contact with the thermal energy storage material is less than about 1 g per m 2 of the wall surface in contact with the thermal energy storage material after 45 days exposure to the thermal energy storage material at 300° C. in an inert atmosphere.