Various embodiments may provide an electromechanical responsive film. The electromechanical responsive film may include a composition including sodium (Na), potassium (K), niobium (Nb) and oxygen (O). The composition may have a formula (Na.sub.xK.sub.y)NbO.sub.3-δ, wherein 0≤x<1, wherein 0≤y<1, and wherein 0<x+y<1. The composition may satisfy at least one condition selected from a group consisting of a first condition of (x+y+4)/2≤(3−δ)≤(x+y+5)/2 and a second condition of 0<δ<1.

A ceramic powder material which contains an LLZ-based garnet-type compound represented by Li.sub.7−3xAl.sub.xLa.sub.3Zr.sub.2O.sub.12 (where x satisfies 0≤x≤0.3) and in which a main phase of a crystal phase undergoes phase transition from a tetragonal phase to a cubic phase in the process of raising a temperature from 25° C. to 1050° C. and the main phase is the cubic phase even after the temperature is lowered to 25° C.

Compositions suitable for reversibly storing heat in thermal energy systems (TES) include a salt hydrate represented by the formula: MX.sub.q.nH.sub.2O. M is a cation selected from Groups 1 to 14 of the IUPAC Periodic Table, X is a halide of Group 17, q ranges from 1 to 4, and n ranges from 1 to 12. The cation (M) may have an electronegativity of ≤ about 1.8 and a molar mass ≤ about 28 g/mol. The anion (X) may have an electronegativity of ≥ about 2.9 to ≤ about 3.2. A distance between a cation (M) and coordinating water molecules (H.sub.2O) is ≤ about 2.1 Å. Thermal energy systems (TES) incorporating such compositions are also provided that are configured to reversibly store heat in the thermal energy system (TES) via an endothermic dehydration reaction and to release heat in in the thermal energy system (TES) via an exothermic hydration reaction.

A ceramic powder material which contains an LLZ-based garnet-type compound represented by Li.sub.7−3xAl.sub.xLa.sub.3Zr.sub.2O.sub.12 (where x satisfies 0≤x≤0.3) and in which a main phase of a crystal phase undergoes phase transition from a tetragonal phase to a cubic phase in the process of raising a temperature from 25° C. to 1050° C. and the main phase is the cubic phase even after the temperature is lowered to 25° C.

A heat storage/dissipation material has a constitution in which heat storage/dissipation titanium oxide made of Ti.sub.3O.sub.5 is dispersed in heat transfer oil in a liquid form, the heat storage/dissipation titanium oxide not undergoing phase transition into a -phase that has properties of a non-magnetic semiconductor and maintaining a state of a paramagnetic metal as long as the heat storage/dissipation titanium oxide is not subjected to pressure or light for heat dissipation. The heat storage/dissipation material is capable of maintaining a state of storing heat as long as the heat storage/dissipation material is not subjected to the pressure or the light for heat dissipation and is capable of releasing heat when subjected to the pressure or the light for heat dissipation, and therefore is capable of releasing the stored heat at a desired timing.

Provided is a method for preparing a stable amorphous calcium carbonate (ACC), which can be obtained either in suspension or as a powder. The method comprises stepwise combination of a soluble calcium salt, a soluble carbonate, a first and second stabilizer, and a water miscible organic solvent as described herein. The present invention further relates to stable ACC suspensions and dry powders produced by the method of the present invention.

A heat storing system includes: a heat source that emits heat to a first thermal medium; and a heat storing unit. The heat storing unit includes a heat storing body container housing a heat storing body, and a thermal medium container housing a liquid phase thermal medium. The heat storing body stores or emits heat in accordance with phase change of the heat storing body. The heat storing unit is configured to conduct a cold heat emission mode in which the liquid phase thermal medium and a cooling medium exchange heat in the thermal medium container to evaporate the thermal medium such that cold heat is emitted to the cooling medium.

A heat storing system includes: a heat source that emits heat to a first thermal medium; and a heat storing unit. The heat storing unit includes a heat storing body container housing a heat storing body, and a thermal medium container housing a liquid phase thermal medium. The heat storing body stores or emits heat in accordance with phase change of the heat storing body. The heat storing unit is configured to conduct a cold heat emission mode in which the liquid phase thermal medium and a cooling medium exchange heat in the thermal medium container to evaporate the thermal medium such that cold heat is emitted to the cooling medium.

Compositions suitable for reversibly storing heat in thermal energy systems (TES) include a salt hydrate represented by the formula: MX.sub.q.Math.nH.sub.2O. M is a cation selected from Groups 1 to 14 of the IUPAC Periodic Table, X is a halide of Group 17, q ranges from 1 to 4, and n ranges from 1 to 12. The cation (M) may have an electronegativity of about 1.8 and a molar mass about 28 g/mol. The anion (X) may have an electronegativity of about 2.9 to about 3.2. A distance between a cation (M) and coordinating water molecules (H.sub.2O) is about 2.1 . Thermal energy systems (TES) incorporating such compositions are also provided that are configured to reversibly store heat in the thermal energy system (TES) via an endothermic dehydration reaction and to release heat in in the thermal energy system (TES) via an exothermic hydration reaction.

Provided is a method for preparing a stable amorphous calcium carbonate (ACC), which can be obtained either in suspension or as a powder. The method comprises stepwise combination of a soluble calcium salt, a soluble carbonate, a first and second stabilizer, and a water miscible organic solvent as described herein. The present invention further relates to stable ACC suspensions and dry powders produced by the method of the present invention.