An inorganic compound for a Li-ion conductor includes an oxyhalide compound with a chemical composition of MOX where M is at least one of Al, Sc, La, and Y, and X is at least one of F, Cl, Br, and I. Also, the oxyhalide compound has a thermal decomposition start temperature of the oxyhalide compound is greater than a thermal decomposition start temperature of FeOCl and a conductivity that is general equal to or greater than a conductivity of the FeOCl.

An inorganic compound for a Li-ion conductor includes an oxyhalide compound with a chemical composition of MOX where M is at least one of Al, Sc, La, and Y, and X is at least one of F, Cl, Br, and I. Also, the oxyhalide compound has a thermal decomposition start temperature of the oxyhalide compound is greater than a thermal decomposition start temperature of FeOCl and a conductivity that is general equal to or greater than a conductivity of the FeOCl.

A lithium-ion conductor includes an inorganic compound with a chemical composition of Li.sub.2−3x+y−zFe.sub.xO.sub.y(OH).sub.1−yCl.sub.1−z, where x is greater than or equal to 0 and less than 1, y is greater than or equal to 0 and less than or equal 1, and z is greater than or equal to 0 and less than or equal 0.25. Also, the inorganic compound has or exhibits a thermal decomposition temperature greater than 390° C., an ionic conductivity greater than about 1.0×10.sup.−4 S/cm at 25° C., and has a crystal structure that reflects or exhibits x-ray diffraction peaks with a 2θ between about 22.12° and about 24.12°, between about 31.97° and about 33.97°, between about 39.55° and about 41.55°, between about 46.46° and about 48.46°, between about 57.77° and about 59.77°, and between about 68.04° and about 70.04°.

A lithium-ion conductor includes an inorganic compound with a chemical composition of Li.sub.2−3x+y−zFe.sub.xO.sub.y(OH).sub.1−yCl.sub.1−z, where x is greater than or equal to 0 and less than 1, y is greater than or equal to 0 and less than or equal 1, and z is greater than or equal to 0 and less than or equal 0.25. Also, the inorganic compound has or exhibits a thermal decomposition temperature greater than 390° C., an ionic conductivity greater than about 1.0×10.sup.−4 S/cm at 25° C., and has a crystal structure that reflects or exhibits x-ray diffraction peaks with a 2θ between about 22.12° and about 24.12°, between about 31.97° and about 33.97°, between about 39.55° and about 41.55°, between about 46.46° and about 48.46°, between about 57.77° and about 59.77°, and between about 68.04° and about 70.04°.

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.

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.

The invention relates to a method and system for phosphate recovery from a stream such as waste flow, sewage or another sludge stream. The method comprises the steps of: providing an incoming stream comprising an initial amount of phosphate; dosing/controlling iron salt to the stream such that precipitates are formed in the stream, wherein the precipitates comprise vivianite like structures comprising more than 60% of the initial amount of phosphate in the incoming stream, and preferably also the steps of: separating the vivianite like structures from the stream; and recovering the phosphates from the separated vivianite like structures.

The invention relates to a method and system for phosphate recovery from a stream such as waste flow, sewage or another sludge stream. The method comprises the steps of: providing an incoming stream comprising an initial amount of phosphate; dosing/controlling iron salt to the stream such that precipitates are formed in the stream, wherein the precipitates comprise vivianite like structures comprising more than 60% of the initial amount of phosphate in the incoming stream, and preferably also the steps of: separating the vivianite like structures from the stream; and recovering the phosphates from the separated vivianite like structures.

Provided is an active material for a fluoride-ion secondary battery, the active material containing a composite fluoride. The composite fluoride has a layered structure and is represented by a composition formula A.sub.mM.sub.nF.sub.x, where A is an alkali metal, M is a transition metal, 0<m≤2, 1≤n≤2, and 3≤x≤4. The alkali metal may be at least one kind selected from the group consisting of Na, K, Rb, and Cs. The transition metal may be a 3d transition metal.

The invention relates to a method for isolating an aqueous hydrochloric acid solution of FeCl.sub.3 from an aqueous multi-component system.