A heat-resistant member (1) according to the present disclosure contains alumina as a main component, and magnesium aluminate and boron. The content percentage of the magnesium aluminate at the surface is higher than the content percentage of the magnesium aluminate in a surface layer section located directly below the surface.

Exemplary embodiments of positive electrode active materials in the form of single particles, and a method of preparing each of them, are provided. The single particles of the exemplary embodiments include single particles of a nickel-based lithium composite metal oxide, having a plurality of crystal grains, each having a size of 180 nm to 300 nm, as analyzed by a Cu Kα X-ray (X-rα). The single particles include a metal doped in the crystal lattice thereof. One embodiment includes a surface coating. The total content of the metal doped in the crystal lattice thereof and the metal of the metal oxide coated on the surface thereof is controlled in the range of 2500 ppm to 6000 ppm.

A method of making stable aqueous dispersions and concentrates of cobalt oxide nanoparticles is described, wherein a reaction mixture comprising cobalt(II) ion, a carboxylic acid, a base, an oxidant and water is formed, and in which cobalt oxide nanoparticles are formed. Cobalt oxide nanoparticles ranging in average crystallite size from about 4 nm to 15 nm are described. The cobalt oxide nanoparticles may be isolated and redispersed to form stable, homogeneous, aqueous dispersions of cobalt oxide nanoparticles containing from about 1 to about 20 weight percent cobalt oxide.

The invention provides for a method of making a magnesium aluminate spinel including an alumina compound and a magnesium compound, the method including the steps of; dispersing the alumina compound by dispersing it in a aqueous solution, to form an alumina dispersion, the aqueous solution having a pH of between 2 and 5; preferably between 2 and 4, flocculating the alumina by increasing the pH of the alumina dispersion to a pH of between 8 and 10 by adding a base; adding the alumina dispersion to an aqueous dispersion of the magnesium compound to form a slurry; drying the slurry to produce a dried spinel precursor; and calcining the dried spinel precursor to produce the magnesium aluminate spinel. Dispersing at such a low pH results in a conversion to spinel as well as allows for the control of the surface area of the spinel.

The present invention relates to a positive electrode active material containing a spinel composite solid solution oxide, a method for manufacturing same, and a lithium secondary battery including the same. The spinel composite solid solution oxide contains cubic (P4.sub.332) and face-centered cubic (Fd-3m) in an optimized solid solution ratio in the crystal, and a low content of lithium nickel oxide (Li.sub.zNi.sub.1−zO) is combined. A positive electrode active material containing the spinel composite solid solution oxide provides excellent output characteristics while having stable cycle-life characteristics according to the type and content of doping elements replacing transition metals, the synthesis temperature, and the amount of impurities generated.

A core-shell particle includes: a core including an iron oxyhydroxide compound represented by Formula A.sup.3.sub.a3Fe.sub.1−a3OOH (in which A.sup.3 represents at least one metal element other than Fe, and a3 satisfies 0<a3<1) or at least one iron oxide compound selected from the group consisting of Fe.sub.2O.sub.3, a compound represented by Formula A.sup.1.sub.a1Fe.sub.2−a1O.sub.3 (in which A.sup.1 represents at least one metal element other than Fe, and a1 satisfies 0<a1<2), Fe.sub.3O.sub.4, and a compound represented by Formula A.sup.2.sub.a2Fe.sub.3−a2O.sub.4 (in which A.sup.2 represents at least one metal element other than Fe, and a2 satisfies 0<a2<2); and a shell which covers the core and includes a polycondensate of a metal alkoxide.

Magnetodielectric (MD) metamaterials have a magnetodielectric (MD) substrate of a ferrite composition or composite having a characteristic impedance matching an impedance of free space and at least one frequency selective surface (FSS). The FSS has a plurality of frequency selective surface elements disposed in a pattern and supported on the MD substrate. The FSS has a conducting composition and is configured to permit one or more of transmission, reflection, or absorption at a selected resonant frequency or selected frequency band. Articles incorporating magnetodielectric metamaterials are provided.

A sputtering target comprising a top coat including a composition of lithium cobalt oxide LiyCozOx. x is smaller than or equal to y+z, and the lithium cobalt oxide has an X-Ray diffraction pattern with a peak P2 at 44°±0.2° 2-theta. The X-Ray diffraction pattern is measured with an X-Ray diffractometer with CuKα1 radiation.

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 positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.