The present invention relates to a lithium metal composite oxide with a layered structure wherein: at least Li, Ni, and an element X are included; the element X is at least one element selected from the group consisting of Co, Mn, Mg, Ca, Sr, Ba, Zn, B, Al, Ga, Ti, Zr, Ge, Fe, Cu, Cr, V, W, Mo, Sc, Y, Nb, La, Ta, Tc, Ru, Rh, Pd, Ag, Cd, In, and Sn; and an average three-dimensional particle unevenness of primary particles with an equivalent spherical diameter of at least 1.0 μm is at least 1.91 and less than 2.9.

Provided is a method for producing an inorganic fluoride luminescent material having excellent light emission characteristics by using a non-aqueous hydrogen fluoride-containing liquid.

The method for producing an inorganic fluoride luminescent material includes: bringing a first inorganic fluoride luminescent material and a non-aqueous hydrogen fluoride-containing liquid having a hydrogen fluoride content in a range of 20% by mass or more and 100% by mass or less into contact with each other to obtain a non-aqueous solution containing ions derived from the first inorganic fluoride luminescent material, and bringing the non-aqueous solution and a non-aqueous organic liquid having a hydrogen fluoride content of less than 20% by mass into contact with each other to precipitate a second inorganic fluoride luminescent material.

This application provides a positive active material, a positive electrode plate, an electrochemical energy storage apparatus, and an apparatus. The positive active material is Li.sub.xNi.sub.yCo.sub.zM.sub.kMe.sub.pO.sub.rA.sub.m, or Li.sub.xNi.sub.yCo.sub.zM.sub.kMe.sub.pO.sub.rA.sub.m with a coating layer on its surface; and the positive active material is single crystal or quasi-single crystal particles, and a particle size D.sub.n10 of the positive active material satisfies: 0.3 μm≤D.sub.n10≤2 μm. In this application, particle morphology of the positive active material and an amount of micro powder in the positive active material are properly controlled, to effectively reduce side reactions between the positive active material and an electrolyte solution, decrease gas production of the electrochemical energy storage apparatus, and improve storage performance of the electrochemical energy storage apparatus without deteriorating an energy density, cycle performance, and rate performance of the electrochemical energy storage apparatus.

A component for a lithium battery including a first layer including a lithium garnet having a porosity of 0 percent to less than 25 percent, based on a total volume of the first layer; and a second layer on the first layer and having a porosity of 25 percent to 80 percent, based on a total volume of the second layer, wherein the second layer is on the first layer and the second layer has a composition that is different from a composition of the first layer.

Provided is a method of producing fine particulate barium calcium titanate in which calcium forms a homogeneous solid solution. The present invention relates to a method of producing a perovskite compound represented by the following formula (1):

Ba.sub.(1-x)A.sub.xTiO.sub.3  (1)

wherein A represents Ca or Sr, and x is a number satisfying 0.00<x≤0.30,

the method including: a first step of acid washing barium titanate to provide barium titanate having a ratio of barium element to titanium element of lower than 1.00; a second step of mixing the barium titanate obtained in the first step and a calcium salt or a strontium salt and drying the mixture to provide a dry mixture; and a third step of heating the dry mixture obtained in the second step.

The positive electrode active material with lithium composite oxide A containing W and Ni and W-free lithium composite oxide B containing Ni. Regarding the lithium composite oxide A, the proportion of Ni relative to the total moles of metal elements except for lithium is 30 to 60 mol %, 50% particle size D50 is 2 to 6 μm, 10% particle size D10 is 1.0 μm or more, and 90% particle size D90 is 6.8 μm or less. Regarding the lithium composite oxide B, the proportion of Ni relative to the total moles of metal elements except for lithium is 50 to 95 mol %, 50% particle size D50 is 10 to 22 μm, 10% particle size D10 is 7.0 μm or more, and 90% particle size D90 is 22.5 μm or less. The mass ratio of the lithium composite oxide B to the lithium composite oxide A is 1:1 to 5.7:1.

In an embodiment a conversion element includes a first phase and a second phase, wherein the first phase comprises lutetium, aluminum, oxygen and a rare-earth element, wherein the second phase comprises Al.sub.2O.sub.3 single crystals, and wherein the conversion element comprises at least one groove.

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 present invention relates to a positive electrode active material which has the structural stability of a lithium composite oxide constituting a positive electrode active material and a lithium secondary battery including the same. The lithium composite oxide constituting the positive electrode active material according to the present invention is able to reduce the surface area and grain boundary of secondary particles having a side reaction with an electrolyte solution, thereby improving high-temperature stability and reducing gas generation caused by the positive electrode active material, and the structural stability of the lithium composite oxide may be improved using a cation-mixing layer covering the surface of a primary particle.

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.