A compound semiconductor which has an improved thermoelectric performance index together with excellent electrical conductivity, and thus may be utilized for various purposes such as a thermoelectric conversion material of thermoelectric conversion devices, solar cells, and the like, and to a method for preparing the same.

The invention relates to a method for producing iron oxide-based composite magnetic nanocomposites, for modulating the magnet grade of the magnetic nanocomposites to, for example, a soft magnetic material, or a semi-hard magnetic material, or a hard magnetic material, comprising the following steps: a0) separate dissolutions of precursors and of a base a) introduction at room temperature of an iron-based precursor (F) and of at least one metal precursor (M) other than an iron-based precursor, and of at least one base (B), and optionally of at least one rare earth precursor (R), in a given order of introduction into the autoclave b) hydrothermal and/or solvothermal production, so as to obtain magnetic nanocomposites which have a main phase and one or more secondary phases M′.sub.2(OH).sub.2O.sub.2 and/or R(OH).sub.3, c) a step of washing the nanocomposites.

A battery includes a positive electrode including a positive electrode active material, a negative electrode, and an electrolytic solution including a lithium hexafluorophosphate and an additive. The positive electrode active material includes a compound having a crystal structure belonging to a space group FM3-M and represented by Compositional Formula (1): Li.sub.xMe.sub.yO.sub.αF.sub.β. The additive is at least one selected from the group consisting of difluorophosphates, tetrafluoroborates, bis(oxalate)borate salts, bis(trifluoromethanesulfonyl)imide salts, and bis(fluorosulfonyl)imide salts.

A positive electrode active material contains a lithium composite oxide containing fluorine and oxygen. The lithium composite oxide satisfies 1<Zs/Za<8, where Zs represents a first ratio of a molar quantity of fluorine to a total molar quantity of fluorine and oxygen in XPS of the lithium composite oxide, and Za represents a second ratio of a molar quantity of fluorine to a total molar quantity of fluorine and oxygen in an average composition of the lithium composite oxide. An XRD pattern of the lithium composite oxide includes a first maximum peak within a first range of 18° to 20° at a diffraction angle 2θ and a second maximum peak within a second range of 43° to 46° at the diffraction angle 2θ. The ratio I.sub.(18°-20°)/I.sub.(43°-46°) of a first integrated intensity I.sub.(18°-20°) of the first maximum peak to a second integrated intensity I.sub.(43°-46°) of the second maximum peak satisfies 0.05≤I.sub.(18°-20°)/I.sub.(43°-46°)≤0.90.

A method for producing a nickel cobalt complex hydroxide includes first crystallization of supplying a solution containing Ni, Co and Mn, a complex ion forming agent and a basic solution separately and simultaneously to one reaction vessel to obtain nickel cobalt complex hydroxide particles, and a second crystallization of, after the first crystallization, further supplying a solution containing nickel, cobalt, and manganese, a solution of a complex ion forming agent, a basic solution, and a solution containing said element M separately and simultaneously to the reaction vessel to crystallize a complex hydroxide particles containing nickel, cobalt, manganese and said element M on the nickel cobalt complex hydroxide particles crystallizing a complex hydroxide particles comprising Ni, Co, Mn and the element M on the nickel cobalt complex hydroxide particles.

The invention relates to a layered double hydroxide (LDH) material and methods for using the LDH material to catalyse the oxygen evolution reaction (OER) in a water-splitting process. The invention also provides a composition, a catalytic material, an electrode and an electrolyser including the LDH material. In particular, the LDH material includes a metal composite including cobalt, iron, chromium and optionally nickel species interspersed with a hydroxide layer.

A thermoelectric conversion material having a high dimensionless figure of merit ZT includes: a large number of polycrystalline grains which include a skutterudite-type crystal structure containing Yb, Co, and Sb; and an intergranular layer which is between the neighboring polycrystalline grains and includes crystals in which an atomic ratio of O to Yb is more than 0.4 and less than 1.5. A method for manufacturing a thermoelectric conversion material includes: a weighing step; a mixing step; a ribbon preparation step by rapidly cooling and solidifying a melt of the raw materials by using a rapid liquid cooling solidifying method; a first heat treatment step including heat treating in an inert atmosphere with an adjusted oxygen concentration; a second heat treatment step including heat treating in a reducing atmosphere; and manufacturing the thermoelectric conversion material by a pressure sintering step in an inert atmosphere.

A method of manufacturing lithium-metal nitride including suspending a lithium—metal-oxide-powder (LMOP) within a gaseous mixture, incrementally heating the suspended LMOP to a holding temperature of between 400 and 800 degrees Celsius such that the LMOP reaches the holding temperature, and maintaining the LMOP at the holding temperature for a time period in order for the gaseous mixture and the LMOP to react to form a lithium-metal nitride powder (LMNP).

Disclosed is a ferromagnetic element-substituted room-temperature multiferroic material having ferromagnetism and ferroelectricity at room temperature, wherein the ferromagnetic element-substituted room-temperature multiferroic material includes a compound of chemical formula 1: <chemical formula 1> (Pb.sub.1-xM.sub.x)Fe.sub.1/2Nb.sub.1/2O.sub.3. In chemical formula 1, M represents a ferromagnetic element, and x represents a number greater than 0 and smaller than 1.

A positive electrode material, including a core and a shell layer are provided. In some embodiments, a molecular formula of the core is Li.sub.1+aNi.sub.xCo.sub.yMn.sub.1-x-yM1.sub.zO.sub.2, 0.8≤x<1.0, 0<y<0.2, 0<a<0.1, 0≤z<0.1, and M1 is selected from at least one of Al, Ta, and B; and a molecular formula of the shell layer is Li.sub.1+bCo.sub.mA1.sub.nNb.sub.1-m-nM2.sub.cO.sub.2, 0.85≤m<1.0, 0<n<0.15, 0<b<0.1, 0.001≤1-m-n≤0.02, 0≤c<0.05, and M2 is selected from at least one of W, Mo, Ti, Zr, Y, and Yb.