The present invention relates to a lithium metal complex oxide and a preparation method thereof, and more particularly, to a lithium metal complex oxide mixed with a metal compound for a lithium reaction, stirred and heat-treated to allow residual lithium and a metal compound for reducing lithium (or a metal compound for lithium reduction) to react with each other on a surface to form a product, which is included in the lithium metal complex oxide, in which the content of Ni.sup.3+ is higher than the content of Ni.sup.2+ and a ratio of Ni.sup.3+/Ni.sup.2+ is 1.5 or greater so that life characteristics and capacity characteristics are improved, while residual lithium is reduced, and a preparation method thereof.

The invention relates to a method for preparing materials with composition gradient characteristics. After mixing a lithium source with the prepared precursor, raise the temperature from room temperature to 300° C.˜600° C. at 2° C./min˜10° C./min and maintain it, and then sinter for 5 hours˜18 hours, cool with the furnace, then raise the temperature from room temperature to 600° C.˜1200° C. at 2° C./min˜10° C./min and maintain it, and sinter for 5 hours˜18 hours, and the material is thus obtained. The material prepared with the method provided by the invention has composition gradient characteristic, and its application to the positive electrode of battery enables the battery to have higher energy density and better thermal stability, and prolonged service life.

A positive electrode active material with little deterioration is provided. Positive electrode active material particles with little deterioration are provided. A power storage device with little deterioration is provided. A highly safe power storage device is provided. A novel power storage device is provided. A secondary battery includes a positive electrode and a negative electrode. In the secondary battery, the positive electrode includes a positive electrode active material; the positive electrode active material includes a crystal exhibiting a layered rock-salt crystal structure; the crystal is represented by the space group R-3m; the positive electrode active material is a particle containing lithium, cobalt, titanium, magnesium, and oxygen; the concentration of the magnesium in a surface portion of the particle is higher than the concentration of the magnesium in an inner portion of the particle; and in the positive electrode active material, the concentration of the titanium in the surface portion of the particle is higher than the concentration of the titanium in the inner portion of the particle.

The present disclosure relates to a novel staged-synthesis method for introduction of various metals in the structure of zeolite frameworks by isomorphous substitution. This new method is based on a hydrothermal synthesis in which the metal addition to the precursor suspensions (gel) is delayed. This so-called “staged-synthesis method” allows to obtain nanosized silanol highly homo- geneous crystalline zeolite structures with a control of the metal location.

The present disclosure provides a porous carbon material having a core-shell structure, which comprises a core comprising a structure formed by stacking carbon sheets, and a shell comprising carbon surrounding the core, and a preparation method thereof, a sulfur-carbon composite comprising the same, and a lithium secondary battery comprising the same.

Provided herein is a method of producing a polyurethane foam. The method includes dispersing turbostratic graphene in a polymerization solution. The polymerization solution includes a first component for polymerization into a polymer. The method includes adding a second component for polymerizing with the first component to chemically convert the polymerization solution into a polyurethane foam. Provided herein is also a polyurethane foam which includes a turbostratic graphene and a polymer formed from the polymerization of a polyol with an isocyanate. Provided herein is also a turbostratic graphene dispersion which includes a turbostratic graphene and a solvent for dispersing the turbostratic graphene.

A hydrogenation catalyst contains a hydrogenation catalyst carrier and an active hydrogenation component. The active hydrogenation component includescompriscs a Group VIB metal sulfide and a Group VIII metal compound, and the molar proportion of a substance of the Group VIII metal compound that interacts with the Group VIB metal sulfide to the total amount of the Group VIII metal compound is 60-100%. The hydrogenation catalyst has a higher active metal sulfurizing degree and a higher number of type II active centers, and can be applied to the hydrogenation treatment process of oil products such as distillate oils and residual oils

The present invention relates to a method of producing a porous composite comprising single-atom metal catalysts and nitrogen atoms by using a hierarchical carbon material from a carbon dioxide-containing gas. According to the present invention, a composite material is produced by producing a porous carbon material using nanosized templates and carbon dioxide, producing carbon nanotubes from the composite material through a self-templating process, and adding single-atom catalysts to the carbon nanofibers. In addition, it is possible to produce a composite having significantly improved porous characteristics and electrochemical properties by nitrogen atom doping using a nitrogen precursor. The produced composite may be easily applied to a high-energy storage device such as a lithium-sulfur battery.

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.

Systems and methods are disclosed for a rock-salt structure formed from an electrochemically-driven amorphous-to-crystalline (a-to-c) transformation of nanostructured Nb.sub.2O.sub.5, the rock-salt structure including, upon cycling with lithium ions (Li+), an insertion of lithium ions (Li+) into Nb.sub.2O.sub.5 to form the rock-salt structure (RS—Nb.sub.2O.sub.5).