A positive electrode active material precursor has a hydroxide represented by Formula 1, wherein the positive electrode active material precursor is a secondary particle, in which a plurality of primary particles are aggregated, and includes crystallines in which major axes of the primary particles are arranged in a direction from a center of the secondary particle toward a surface thereof and a (001) plane of the primary particle is arranged parallel to the major axis of the primary particle. A method of preparing the positive electrode active material precursor, and a positive electrode active material prepared by using the positive electrode active material precursor are also provided.

This positive-electrode active material for a non-aqueous electrolyte secondary battery contains a lithium and transition metal composite oxide represented by the composition formula: Li.sub.xMn.sub.yNi.sub.zSr.sub.aM.sub.bO.sub.2-cF.sub.c (where, M is at least two elements selected from Ti, Co, Si, Al, Nb, W, Mo, P, Ca, Mg, Sb, Na, B, V, Cr, Fe, Cu, Zn, Ge, Zr, Ru, K, and Bi; 1.0<x≤1.2; 0.4≤y≤0.8; 0≤z≤0.4; 0<a<0.01; 0<b<0.03; 0<c<0.1; and x+y+z+a+b≤2).

A hexagonal ferrite magnetic powder is significantly more useful for achieving simultaneously both the enhancement of the recording density and the enhancement of the SNR of a magnetic recording medium. The hexagonal ferrite magnetic powder contains Bi at a Bi/Fe molar ratio in a range of 0.035 or less, has a saturation magnetization σs of 42.0 Am.sup.2/kg or more and a Dx volume calculated based on the crystallite diameters of 1,800 nm.sup.3 or less. A method for producing hexagonal ferrite magnetic powder includes a step of performing a treatment of immersing hexagonal ferrite magnetic powder containing Bi in a solution having dissolved therein a compound X that forms a complex with Bi, so as to elute a part of Bi existing in the hexagonal ferrite magnetic powder into the solution.

A method of preparing a bimodal positive electrode active material precursor and a positive electrode active material prepared from the same are disclosed herein. In some embodiments, the method includes inputting a first reaction source material including a first aqueous transition metal solution into a reactor, precipitating at pH 12 or more to induce nucleation of a first positive electrode active material precursor particle, and at less than pH 12 to induce growth of the same, inputting a second reaction source material including a second aqueous transition metal solution into the reactor containing the first positive electrode active material precursor particle, precipitating at pH 12 or more to induce the nucleation of a second positive electrode active material precursor particle, and at less than pH 12 to induce simultaneous growth of the first and second positive electrode active material precursor particles, thereby preparing a bimodal positive electrode active material precursor.

There is provided a method for collecting and reusing an active material from positive electrode scrap. The method of reusing a positive electrode active material of the present disclosure includes (a) thermally treating a positive electrode scrap comprising an active material layer comprising nickel, cobalt and manganese on a current collector in air for thermal decomposition of a binder and a conductive material in the active material layer, to separate the current collector from the active material layer, and collecting an active material in the active material layer, (b) washing the active material collected form the step (a) with a lithium compound solution which is basic in an aqueous solution and drying, and (c) annealing the active material washed from the step (b) with an addition of a lithium precursor to obtain a reusable active material.

A method of preparing a positive electrode active material is disclosed herein. In some embodiments, the method includes firing a first mixture at 400° C. to 700° C. to prepare a primary firing product, wherein the first mixture has a positive electrode active material precursor having a specific composition, a first lithium-containing source material, and optionally, an aluminum-containing source material, and firing a second mixture at a temperature above the firing temperature of the first mixture to prepare a positive electrode active material, wherein the second mixture has the primary firing product, a second lithium-containing source material, and a specific doping element M.sup.1-containing source material. The method is capable of degrading the cake strength of a primary firing product and providing a positive electrode active material having excellent quality by dividing a firing process into two steps.

A zirconia sintered body is provided and includes yttria and zirconia, containing yttria by a content ranging from 4.5 mol % or more to 6.5 mol % or less and zirconia as the remainder, the total light transmittance of a 1-mm thick sample measured in compliance with JIS K 7361-1 being 46.5% or higher, the three-point bending strength being 700 MPa or higher, and a ratio of an integrated value for the total light transmittance to an integrated value for the parallel light transmittance of a 1-mm thick sample measured at the measurement wavelength ranging from 400 to 700 nm being 1.3% or less.

The present application provides a high-nickel ternary positive electrode active material, which comprises a core Li.sub.1+a[LixCoyMn.sub.zM.sub.b]O.sub.2, a fast ionic conductor Li.sub.αAl.sub.XSi.sub.YO.sub.4 of a first shell layer, an oxide of an element R of a second shell layer, and a transition layer Li.sub.pR.sub.qO.sub.w formed between the first shell layer and the second shell layer. In the high-nickel ternary positive electrode active material of the present application, the surface impurity lithium amount is significantly reduced, and by creatively converting the surface impurity lithium into effective components in the fast ionic conductors Li.sub.αAl.sub.XSi.sub.YO.sub.4 and Li.sub.pR.sub.qO.sub.w which accelerate the intercalation/deintercalation of lithium ions in the core material, the decomposition and gas production of an electrolyte solution caused by the surface impurity lithium is greatly improved, such that a high-nickel ternary lithium-ion battery has high energy density as well as good cycle performance and safety performance.

The present invention is to provide a method for producing nanodiamonds doped with a Group 14 element, the method comprising: detonating by exploding an explosive composition containing at least one explosive and at least one Group 14 element compound in a sealed container to obtain nanodiamonds doped with at least one Group 14 element selected from the group consisting of Si, Ge, Sn, and Pb, and removing the Group 14 element and/or oxide thereof by subjecting the nanodiamonds doped with a Group 14 element to an alkali treatment.

A lithium complex oxide and method of manufacturing the same, more particularly, a lithium complex oxide effective in improving the characteristics of capacity, resistance, and lifetime with reduced residual lithium and with different interplanar distances of crystalline structure between a primary particle locating in an internal part of secondary particle and a primary particle locating on the surface part of the secondary particle, and a method of preparing the same.