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.

Provided are methods of stabilizing MXene compositions using polyanionic salts so as to reduce the oxidation of the MXenes. Also provided are stabilized MXene compositions.

Electrode active material comprising (A) a core material according to general formula Li.sub.1+x1TM.sub.1−x1O.sub.2 wherein TM is a combination of Ni and at least one of Mn, Co and Al, and, optionally, at least one more metal selected from Mg, Ti, Zr, Nb, Ta, and W, and x1 is in the range of from −0.05 to 0.2, and (B) particles of cobalt compound(s) and of aluminum compound(s) and of titanium compound(s) or zirconium compound(s) wherein the molar ratio of lithium to cobalt in said particles is in the range of from zero to below 1 and wherein said particles are attached to the surface of the core material.

The present disclosure relates to a positive active material, a method of preparing the same, and a lithium secondary battery having a positive electrode including the positive active material, the positive active material including: a lithium transition metal oxide having a portion of Li substituted by Na, and including Ni and Co; and a cobalt-containing coating layer arranged on the surface of the lithium transition metal oxide particle, wherein the lithium transition metal oxide particle includes a concentration gradient region in which the concentration of Co decreases in a direction from the surface to the center of the particle.

The present invention relates to a positive electrode active material comprising an overlithiated layered oxide (OLO) and, more specifically, to a positive electrode active material comprising: an OLO represented by chemical formula 1 below; and an amorphous free oxide coating layer of an amorphous free oxide on the surface of the OLO represented by chemical formula 1. [Chemical formula 1] Li.sub.2MnO.sub.3.(1-r)Li.sub.aNi.sub.xCo.sub.yMn.sub.zM1.sub.1-(x+y+z)O.sub.2 (wherein, in chemical formula 1, 0<r≤0.6, 0<a≤1, 0≤x≤1, 0≤y<1, 0≤z<1, and 0<x+y+z≤1, and M1 is at least any one selected from Na, K, Mg, Al, Fe, Cr, Y, Sn, Ti, B, P, Zr, Ru, Nb, W, Ba, Sr, La, Ga, Mg, Gd, Sm, Ca, Ce, Fe, Al, Ta, Mo, Sc, V, Zn, Cu, In, S, B, Ge, Si, and Bi).

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.

The invention relates to a phosphor with garnet structure and a light-emitting device comprising the phosphor, wherein the phosphor includes the following components in percentage by weight: 38.47-45.19% of Y element, 9.49-22.09% of Al element, 2.06-24.31% of Ga element, 27.3-32.04% of O element, 0.43-1.46% of Ce element. In the phosphor particles, the shortest distance from the surface of one side of the particle to the surface of the opposite side through the centroid of the particle is defined as R, the longest distance is R1, and 5 μm≤R≤40 μm; any distance from the particle surface to the centroid is r, and 0<r<½R; and the space with the distance from the particle surface to the centroid direction being less than or equal to r is defined as r.sub.inner.

The present disclosure relates to a positive electrode active material, a method of manufacturing the same, and a lithium secondary battery including a positive electrode including the same. The positive electrode active material includes: a lithium transition metal oxide particle in which a portion of Li is substituted with Na, and which includes Ni and Co atoms; and a phosphorus-containing coating layer disposed on the surface of the lithium transition metal oxide particle, wherein the lithium transition metal oxide particle includes a concentration gradient region in which the concentration of Co atoms decreases from the surface toward the center of the particle.

This application discloses a positive electrode active material and a preparation method thereof, a positive electrode plate, a lithium-ion secondary battery, and a battery module, battery pack, and apparatus containing such lithium-ion secondary battery. The positive electrode active material includes bulk particles and an element M.sup.1-containing oxide coating layer applied on an exterior surface of each of the bulk particles. The bulk particle includes a nickel-containing lithium composite oxide. Bulk phases of the bulk particles are uniformly doped with element M.sup.2. A surface layer of the bulk particle is an exterior doped layer doped with element M.sup.3. Element M.sup.1 and element M.sup.3 are each independently selected from one or more of Mg, Al, Ca, Ce, Ti, Zr, Zn, Y, and B, and element M.sup.2 includes one or more of Si, Ti, Cr, Mo, V, Ge, Se, Zr, Nb, Ru, Rh, Pd, Sb, Te, Ce, and W.

A method of preparing a positive electrode active material includes preparing a lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium, impregnating the lithium transition metal oxide with 300 ppm to 1,000 ppm of moisture based on 100 parts by weight of the lithium transition metal oxide, and performing a heat treatment on the lithium transition metal oxide impregnated with the moisture, wherein a lithium by-product present on a surface of the lithium transition metal oxide and the moisture react to form a passivation layer on the surface of the lithium transition metal oxide. A positive electrode active material prepared by the above-described preparation method, and a positive electrode and a lithium secondary battery which include the positive electrode active material are also provided.