Thermochemical storage materials having the general formula A.sub.xA.sub.1-xB.sub.yB.sub.1-yO.sub.3-, where A=La, Sr, K, Ca, Ba, Y and B=Mn, Fe, Co, Ti, Ni, Cu, Zr, Al, Y, Cr, V, Nb, Mo, are disclosed. These materials have improved thermal storage energy density and reaction kinetics compared to previous materials. Concentrating solar power thermochemical systems and methods capable of storing heat energy by using these thermochemical storage materials are also disclosed.

Oxide compositions comprising a modified structure which includes the formula ABO.sub.z. The A component may comprise at a cation of least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Gd, and Zn, and the B component may comprise a cation of at least one element selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni. Batteries and supercapacitors comprising the oxide compositions of the present disclosure and methods of making the oxide compositions of the present disclosure are also provided.

A cathode and a battery including a cathode active material including a layer-structured material having a composition of xLi.sub.2MO.sub.3-(1-x)LiMeO.sub.2; and a metal oxide having a perovskite structure. The cathode active material may have improved structural stability by intermixing a metal oxide having a similar crystalline structure with the layer-structured material, and thus, life and capacity characteristics of a cathode and a lithium battery including the metal oxide may be improved.

Oxide compositions comprising a modified structure which includes the formula ABO.sub.z. The A component may comprise at a cation of least one element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Gd, and Zn, and the B component may comprise a cation of at least one element selected from the group consisting of V, Cr, Mn, Fe, Co, and Ni. Batteries and supercapacitors comprising the oxide compositions of the present disclosure and methods of making the oxide compositions of the present disclosure are also provided.

A perovskite material represented by Formula 1:
Li.sub.xA.sub.yM.sub.zO.sub.3-?Formula 1 wherein in Formula 1, 0<x?1, 0<y?1, 0<x+y<1, 0<z?1.5, 0???1, A is H, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, or a combination thereof, and M is Ni, Pd, Pb, Fe, Ir, Co, Rh, Mn, Cr, Ru, Re, Sn, V, Ge, W, Zr, Mo, Hf, U, Nb, Th, Ta, Bi, Li, H, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Mg, Al, Si, Sc, Zn, Ga, Ag, Cd, In, Sb, Pt, Au, or a combination thereof.

A ceramic material has a composition represented by the formula: La-.sub.1-x-yAE.sub.yMnO.sub.3 in which AE is at least one of Ca and Sr; x satisfies 0<x about 0.20; and y satisfies 0<yabout 0.10.

In a perovskite-type composite oxide powder according to the present invention, the geometric standard deviation value of the maximum Feret diameter of the perovskite-type composite oxide powder calculated by performing image analysis on an SEM image acquired with a scanning electron microscope is equal to or greater than 1.01 and less than 1.60, and when it is assumed that the perovskite-type composite oxide powder is spherical, the ratio (B/A) of an area value B directly calculated by the image analysis to an area value A calculated from the maximum Feret diameter is equal to or greater than 0.7 and less than 1.0. In this way, the perovskite-type composite oxide powder is used as the air electrode material of an SOFC, and thus high conductivity as compared with a conventional air electrode material is obtained.

A thermal emission structure capable of exhibiting heat release characteristics reverse to those of a Phase-change material used therein includes a first conductor layer, a dielectric layer on the first conductor layer, and a second conductor layer on the dielectric layer and having a periodic geometry, at least one of the first conductor layer and the second conductor layer comprises a Phase-change material having an electrical conduction property that varies between a high-temperature phase and a low-temperature phase.

A solar power system and materials capable of storing heat energy by thermochemical energy storage are disclosed. Thermal energy is stored as chemical potential in these materials through a reversible reduction-oxidation reaction. Thermal energy from concentrated sunlight drives a highly endothermic reduction reaction that liberates lattice oxygen from the oxide to form O.sub.2 gas, leaving energy-rich, oxygen-depleted particles. When desired, the heat is recovered as the particles are re-oxidized in an exothermic reaction upon exposure to air. The system may be integrated with a power generation system to generate power.

Embodiments of the present disclosure are directed to hydrogen-selective oxygen carrier materials and methods of using hydrogen-selective oxygen carrier materials. The hydrogen-selective oxygen carrier material may comprise a core material, which includes a redox-active transition metal oxide; a shell material, which includes one or more alkali transition metal oxides; and a support material. The shell material may be in direct contact with at least a majority of an outer surface of the core material. At least a portion of the core material may be in direct contact with the support material. The hydrogen-selective oxygen carrier material may be selective to combust hydrogen in an environment that includes hydrogen and hydrocarbons.