Disclosed is AA′ graphite with a new stacking feature of graphene, and a fabrication method thereof. Graphene is stacked in the sequence of AA′ where alternate graphene layers exhibiting the AA′ stacking are translated by a half hexagon (1.23 Å). AA′ graphite has an interplanar spacing of about 3.44 Å larger than that of the conventional AB stacked graphite (3.35 Å) that has been known as the only crystal of pure graphite. This may allow the AA′ stacked graphite to have unique physical and chemical characteristics.

The present invention is directed to methods of transferring urea from an aqueous solution comprising urea to a MXene composition, the method comprising contacting the aqueous solution comprising urea with the MXene composition for a time sufficient to form an intercalated MXene composition comprising urea.

A new family of crystalline microporous metalloalumino(gallo)phosphosilicate molecular sieves has been synthesized and are designated high charge density (HCD) MeAPSOs. These metalloalumino(gallo)phosphosilicate are represented by the empirical formula of:

R.sup.p+.sub.rA.sup.+.sub.mM.sup.2+.sub.wE.sub.xPSi.sub.yO.sub.z

where A is an alkali metal such as potassium, R is at least one quaternary ammonium cation such as ethyltrimethylammonium, M is a divalent metal such as Zn and E is a trivalent framework element such as aluminum or gallium. This family of metalloalumino(gallo)phosphosilicate materials are stabilized by combinations of alkali and quaternary ammonium cations, enabling unique, high charge density compositions. The HCD MeAPSO family of materials have catalytic properties for carrying out various hydrocarbon conversion processes and separation properties for separating at least one component.

A cathode active material precursor for a lithium secondary battery has a structure of a nickel composite hydroxide. A first peak intensity ratio represented by Equation 1 is 0.5 or more, and a second peak intensity ratio represented by Equation 2 is 0.7 or more. A cathode active material and a lithium secondary battery having a stabilized crystal structure are provided using the cathode active material precursor.

The present invention relates, in general terms, to piezoelectric thin films with an empirical formula (K.sub.1xNa.sub.x).sub.yNbO.sub.3, wherein 0≤x≤1 and 0.64≤y≤0.95. In particular, the piezoelectric thin film comprises at least two adjacent NbO.sub.2 planes in an antiphase boundary, the at least two adjacent NbO.sub.2 planes displaced from each other by about half a lattice length in either the (100), (010) or (100) crystallographic plane. The present invention also relates to methods of fabricating the piezoelectric thin films.

To provide a crystalline oxide semiconductor film, an ion is made to collide with a target including a crystalline In—Ga—Zn oxide, thereby separating a flat-plate-like In—Ga—Zn oxide in which a first layer including a gallium atom, a zinc atom, and an oxygen atom, a second layer including an indium atom and an oxygen atom, and a third layer including a gallium atom, a zinc atom, and an oxygen atom are stacked in this order; and the flat-plate-like In—Ga—Zn oxide is irregularly deposited over a substrate while the crystallinity is maintained.

A chalcogen-containing compound of the following Chemical Formula 1, which may have decreased thermal conductivity and improved power factor in the low temperature region, and thus exhibit an excellent thermoelectric figure of merit, a method for preparing the same, and a thermoelectric element including the same:
V.sub.1Sn.sub.a−xIn.sub.xSb.sub.2Te.sub.a+3  [Chemical Formula 1]
wherein V, a and x are as defined in the specification.

The present invention relates to a positive electrode active material having improved capacity characteristic and life cycle characteristic, and a method of preparing the same, and specifically, to a positive electrode active material for a lithium secondary battery, wherein the positive electrode active material comprises a compound represented by Formula 1 above and allowing reversible intercalation/deintercalation of lithium, and from a crystal structure analysis of the positive electrode active material by a Rietveld method in which space group R-3m is used in a crystal structure model on the basis of an X-ray diffraction analysis, the thickness of MO slab is 2.1275 Å or less, the thickness of inter slab is 2.59 Å or greater, and the cation mixing ratio between Li and Ni is 0.5% or less, and a method of preparing the same.

Single crystals of a new noncentrosymmetric polar oxysulfide SrZn.sub.2S.sub.2O (s.g. Pmn2.sub.1) grown in a eutectic KF-KCl flux with unusual wurtzite-like slabs consisting of close-packed corrugated double layers of ZnS.sub.3O tetrahedra vertically separated from each other by Sr atoms and methods of making same.

The present application discloses a positive electrode active material satisfying the chemical formula L.sub.xNa.sub.yM.sub.zCu.sub.αFe.sub.βMn.sub.γO.sub.2+δ−0.5ηX.sub.η and a preparation method therefor, a sodium ion battery and an apparatus including such battery, wherein L is a doping element at alkali metal site, M is a doping element at transition metal site, and X is a doping element at oxygen site, 0≤x<0.35, 0.65≤y≤1, 0<α≤0.3, 0<β≤0.5, 0<γ≤0.5, −0.03≤δ≤0.03, 0≤η≤0.1, z+α+β+γ=1, mx+y+nz+2α+3β+4γ=2(2+δ), m is the valence state of L, and n is the valence state of M; and the pH of the positive electrode active material is 10.5-13, wherein L is a doping element at alkali metal site, M is a doping element at transition metal site, and X is a doping element at oxygen site.