The present disclosure relates to a positive electrode active material, a preparing method therefor, and a lithium secondary battery including same. A positive electrode active material according to an embodiment comprises: a core including a lithium nickel composite oxide represented by Chemical Formula 1; and a surface layer present on the core and including at least one of a water-soluble ammonium-based organic compound and a water-soluble amine-based organic compound. The details of Chemical Formula 1 are as defined in the specification.

The cathode active material is capable of reducing cathode resistance of a secondary battery by enhancing electron conductivity thereof without reducing discharge capacity of the secondary battery. The method for manufacturing a cathode active material includes: mixing transition metal-containing composite compound particles containing lanthanum with a lithium compound to obtain a lithium mixture; calcinating the lithium mixture at a temperature equal to or lower than the melting point of the lithium compound; and then subjecting the lithium mixture to main firing at a firing temperature within a range of 725° C. to 1000° C. Lithium carbonate is preferably used as the lithium compound, and in this case, the calcination temperature is within a range of 600° C. to 723° C. It is preferable to obtain the transition metal-containing composite compound particles containing lanthanum by a coprecipitation method and to uniformly disperse a lanthanum element in the particles.

The present invention relates to a ceramic solid electrolyte, which is a key component of an all-solid-state lithium secondary battery, for improving safety, and a method for synthesizing the same. The present invention relates to an oxide-based conductive ceramic of a new NASICON structure of the chemical formula Li.sub.1+xAl.sub.xX.sub.2−xP.sub.3O.sub.12 (X is Zr, Si, Sn, or Y, 0<x<2) or Li.sub.1+xZr.sub.2X.sub.xP.sub.3−xO.sub.12 (X=Si, Sn, Ge, or Y, 1.5≤x≤2.3). The present invention relates to a method for manufacturing an oxide-based conductive ceramic having the above novel NASICON structure.

A method of producing a positive electrode material for a secondary battery includes preparing a lithium composite transition metal oxide containing nickel, cobalt, and manganese, forming a coating layer on a surface of the lithium composite transition metal oxide, and post-treating the lithium composite transition metal oxide having the coating layer formed thereon, wherein the post-treating is performed by exposing the lithium composite transition metal oxide having the coating layer formed thereon to moisture at a relative humidity of 10% to 50% at 25° C., and then heat treating the lithium composite transition metal oxide to remove residual moisture.

A paramagnetic garnet-type transparent ceramic is a sintered body of complex oxide represented by the following formula (1), comprising SiO.sub.2 as a sintering aid in an amount of more than 0% by weight to 0.1% by weight or less, and has a linear transmittance of 83.5% or more at the wavelength of 1,064 nm for an optical path length of 25 mm:
(Tb.sub.1-x-yY.sub.xSc.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
wherein 0.05≤x<0.45, 0<y<0.1, 0.5<1−x−y<0.95, and 0.004<z<0.2.

Provided is a titanium oxide particle dispersion liquid with an inhibited photocatalytic activity and a low level of coloration. Titanium oxide particles in this dispersion liquid contain:

(1) a tin component; and

(2) a manganese component and/or a cobalt component,

wherein only the tin component is solid-dissolved in the titanium oxide particles, and the manganese component and/or the cobalt component are each contained by an amount of 5 to 5,000 in terms of a molar ratio to titanium (Ti/Mn and/or Ti/Co).

A positive electrode active material precursor, a method of preparing the same, and a positive electrode active material, a positive electrode, and a lithium secondary battery prepared from the same. In some embodiments, a positive electrode active material precursor includes nickel, cobalt, and manganese, wherein the positive electrode active material precursor satisfies: Equation 1 (2.5≤C.sub.(100)/C.sub.(001)≤5.0) and Equation 2 (1.0≤C.sub.(101)/C.sub.(001)≤3.0), where C.sub.(001) is a crystalline size in a (001) plane, C.sub.(100) is a crystalline size in a (100) plane, and C.sub.(101) is a crystalline size in a (101) plane. The positive electrode active material precursor has particle growth of a (001) plane that is suppressed.

Provided are a chalcogenide material, and a device and a memory device each including the same. The chalcogenide material may include: germanium (Ge) as a first component; arsenic (As) as a second component; at least one element selected from selenium (Se) and tellurium (Te) as a third component; and at least one element selected from the elements of Groups 2, 16, and 17 of the periodic table as a fourth component, wherein a content of the first component may be from 5 at % to 30 at %, a content of the second component may be from 20 at % to 40 at %, a content of the third component may be from 25 at % to 75 at %, and a content of the fourth component may be from 0.5 at % to 5 at %.

A prussian blue analog having a core-shell structure, which has a core and a cladding layer that dads the core, wherein

the chemical formula of the core is the following Formula 1,

Na.sub.xP[R(CN).sub.6].sub.δ.zH.sub.2O and the chemical formula of the cladding layer is the following Formula 2, A.sub.yL[M(CN).sub.6].sub.α.wH.sub.2O is described. The prussian blue analog has good storage stability, and thus can greatly reduce the manufacturing cost at the subsequent battery cell level. A method for preparing the prussian blue analog having a core-shell structure, as well as a sodium-ion secondary battery, a battery module, a battery pack and a powered device comprising the same are described.

An advantage is to provide a non-aqueous electrolyte secondary battery with improved heat resistance. A positive electrode active material contains a lithium-transition metal composite oxide containing 80 mol % or more of Ni and 0.1 mol % to 1.5 mol % of B on the basis of the total number of moles of metal elements excluding Li, and B and at least one element (M1) selected from Groups 4 to 6 are present on at least the surfaces of particles of the composite oxide. When particles having a volume-based particle size larger than 70% particle size (D70) are first particles, and particles having a volume-based particle size smaller than 30% particle size (D30) are second particles, the molar fraction of M1 on the basis of the total number of moles of metallic elements excluding Li on the surfaces of the second particles is greater than that of the first particles.