Disclosed herein is a stabilised Na-ion oxide P3 phase of formula (I): P3-Na.sub.xM.sub.yO.sub.z Where, x>0.66, 0.8≤y≤1.0, z≤2; and M is selected from one or more of the group consisting of a 3d transition metal, a 4d transition metal, Al, Mg, B, Si, Sn, Sr and Ca. The stabilised Na-ion oxide P3 phase of formula (I) may be particularly useful as an active material in a Na-ion battery.

A phosphor contains a crystal phase having a chemical composition Ce.sub.xM.sub.3-x-yβ.sub.6γ.sub.11-z. M is one or more elements selected from the group consisting of Sc, Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. β contains Si in an amount of 50 mol % or more of a total mol of β. γcontains N in an amount of 80 mol % or more N of a total mol of γ. x satisfies 0<x≦0.6. y satisfies 0≦y≦1.0. z satisfies 0≦z≦1.0. The phosphor shows a maximum peak of an emission spectrum in a wavelength range of 600 nm or more and 800 nm or less and a first peak of an excitation spectrum in a wavelength range of 500 nm or more and 600 nm or less.

A lithium-manganese composite oxide containing a lithium-iron-manganese composite oxide represented by the composition formula. Li.sub.1+x−w(Fe.sub.yNi.sub.zMn.sub.1−y−z).sub.1−xO.sub.2−δ, where 0<x<⅓, 0≤w<0.8, 0<y<1, 0<z<0.5, y+z<1, and 0≤δ<0.5, in which at least in a state of charge of a lithium ion battery using the lithium-manganese composite oxide as a positive-electrode active material, at least some of iron atoms are pentavalent.

A hydrotalcite is represented by formula (1):
(M.sup.2+).sub.1-X(M.sup.3+).sub.X(OH).sub.2(A.sup.n−).sub.X/n.Math.mH.sub.2O  (1), wherein M.sup.2+ indicates a divalent metal, M.sup.3+ indicates a trivalent metal, A.sup.n− indicates an n-valent anion, n indicates an integer of 1 to 6, 0.17≤x≤0.36, and 0≤m≤10. The hydrotalcite has (A) a lattice strain in the <003> direction is 3×10.sup.−3 or less as measured using an X-ray diffraction method; (B) primary particles with an average width between 5 nm and 200 nm inclusive per a SEM method; and (C) a degree of monodispersity of 50% or greater (degree of monodispersity (%)=(average width of primary particles as measured using the SEM method/average width of secondary particles as measured using a dynamic light scattering method)×100). A resin containing the hydrotalcite, a suspension containing the hydrotalcite and a method for producing the hydrotalcite are disclosed.

A layered double hydroxide is represented by the following formula (I): Ni.sup.2+.sub.1−(x+y+z)Fe.sup.3+.sub.xV.sup.3+.sub.yCo.sup.3+.sub.z(OH).sub.2A.sup.n−.sub.(x+y+z)/n.Math.mH.sub.2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, “x” represents more than 0 and 0.3 or less, “y” represents from 0.04 to 0.49, and “z” represents more than 0 and 0.2 or less.

A lithium cobalt-based positive electrode active material is provided. The lithium cobalt-based positive electrode active material includes a core portion including a lithium cobalt-based oxide represented by Formula 1 and a shell portion including a lithium cobalt-based oxide represented by Formula 2, wherein the lithium cobalt-based positive electrode active material includes 2500 ppm or more, preferably 3000 ppm or more of a doping element M based on the total weight of the positive electrode active material. An inflection point does not appear in a voltage profile measured during charging/discharging a secondary battery including the lithium cobalt-based positive electrode active material.

A method for preparing a composition including mineral particles functionalized by at least one organic group and having a specific surface defined according to the BET method greater than 500 m.sup.2/g, involves: —choosing a phyllosilicate composition, including mineral particles having a thickness of less than 100 nm, a largest dimension of less than 10 μm and belonging to the family of lamellar silicates; —choosing at least one functionalizing agent, from the group formed from the oxysilanes and oxygermanes having at least one organic group, —bringing the phyllosilicate composition into contact with a functionalizing solution including the functionalizing agent, so as to obtain a phyllosilicate composition including mineral particles functionalized by the organic group, while choosing the organic group from the group formed from the cationic heteroaryl groups, the quaternary ammonium groups and the salts of same. The phyllosilicate composition obtained by the method is also described.

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 nickel hydroxide includes stacked nickel hydroxide layers. Each of the nickel hydroxide layers includes Ni.sup.2+ and OH.sup.−. At least one of the nickel hydroxide layers further includes a type of polyatomic anions. The polyatomic anions include a type of anions that are not SO.sub.4.sup.2− or CO.sub.3.sup.2−.

The present invention relates to a quantum dot and a preparation method therefor, and more specifically, to a novel quantum dot composite having high surface stability, and a preparation method therefor. The quantum dot composite according to the present invention constitutes a layered-structure ceramic composite in which the layered-structure ceramic comprises a polymer-quantum dot composite between the layers thereof.