A method of producing a positive electrode active material for a nonaqueous electrolyte secondary battery, the method includes preparing nickel-containing composite oxide particles having a ratio .sup.1D.sub.90/.sup.1D.sub.10 of a 90% particle size .sup.1D.sub.90 to a 10% particle size .sup.1D.sub.10 in volume-based cumulative particle size distribution is 3 or less; mixing the composite oxide particles and a lithium compound to obtain a first mixture; subjecting the first mixture to a first heat treatment at a first temperature and a second heat treatment at a second temperature higher than the first temperature to obtain a first heat-treated product; and subjecting the first heat-treated material to a dispersion treatment.

A composite material comprising NiMoO.sub.4—CoMoO.sub.4 nanosheets can be an electrode in a hybrid supercapacitor. A hybrid supercapacitor having a cathode comprising the composite material exhibits a large operating window, high energy density and high cycling stability. The heterostructure material may be formed by a one-step chemical bath deposition process.

A method for preparing a bimodal-type positive electrode active material precursor is provided. The method is capable of not only increasing productivity by preparing positive electrode active material precursors having small diameters and large diameters in a single reactor but also improving packing density per unit volume, a positive electrode active material precursor prepared by the preparation method and having improved packing density, and a positive electrode for a secondary battery and a lithium secondary battery including the same.

The present disclosure relates to a cathode active material for a lithium secondary battery, a preparation method therefor, and a lithium secondary battery comprising same, and the cathode active material includes a lithium nickel cobalt manganese-based oxide represented by Chemical Formula 1 including secondary particles obtained by agglomerating at least one primary particle, and a metal oxide particles having a nano-sized average diameter (D50) and disposed inside the secondary particles.

Li.sub.a[Ni.sub.xCo.sub.yMn.sub.z].sub.tM.sub.1-tO.sub.2-pX.sub.p.  [Chemical Formula 1]

The disclosure discloses a nickel cobalt manganese hydroxide, a cathode material, a preparation method thereof and a lithium ion battery. The nickel cobalt manganese hydroxide comprises a core and an outer layer covering the outside of the core. The core comprises flaky particles, the D.sub.50 particle diameter of the flaky particles in the core is 5-8 μm, and the D.sub.50 particle diameter of particles in the outer layer is 0.1-5 μm.

Described herein is a nanocrystalline ferrite having the formula Ni.sub.1−x−yM.sub.yCo.sub.xFe.sub.2+zO.sub.4, wherein M is at least one of Zn, Mg, Cu, or Mn, x is 0.01 to 0.8, y is 0.01 to 0.8, and z is −0.5 to 0.5, and wherein the nanocrystalline ferrite has an average grain size of 5 to 100 nm. A method of forming the nanocrystalline ferrite can comprise high energy ball milling.

A method for producing mixed metal salts containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a precipitation step of neutralizing an extracted residual liquid obtained in the Al removal step under conditions where a pH is less than 10.0, to precipitate mixed metal salts comprising a metal salt of manganese and a metal salt of at least one of cobalt and nickel.

A positive electrode active material for nonaqueous electrolyte secondary batteries according to one embodiment of the present disclosure contains a lithium transition metal composite oxide which is represented by general formula Li.sub.aNi.sub.bCo.sub.cAl.sub.dX.sub.eO.sub.f (wherein 0.9≤a≤1.2; 0.88≤b≤0.96; 0≤c≤0.12; 0≤d≤0.12; 0≤e≤0.1; 1.9≤f≤2.1; (b+c+d)=1; and X represents at least one element that is selected from among Mn, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W and B); and the lithium transition metal composite oxide has a pore volume of pores having a pore diameter of 0.3 μm or less of from 6×10.sup.−4 mL/g to 50×10.sup.−4 mL/g, while having a particle fracture strength of 120 MPa or more at the volume average particle diameter.

A precursor for a lithium secondary battery positive electrode active material containing at least a nickel atom, in which, in a volume-based cumulative particle size distribution curve that is obtained by laser diffraction type particle size distribution measurement, a particle diameter (.Math.m) at which a cumulative volume fraction from a small particle side becomes 10% is defined as D.sub.10, a particle diameter (.Math.m) at which the cumulative volume fraction from the small particle side becomes 30% is defined as D.sub.30, a particle diameter (.Math.m) at which the cumulative volume fraction from the small particle side becomes 50% is defined as D.sub.50, a particle diameter (.Math.m) at which the cumulative volume fraction from the small particle side becomes 70% is defined as D.sub.70, and a particle diameter (.Math.m) at which the cumulative volume fraction from the small particle side becomes 90% is defined as D.sub.90, the D.sub.10, the D.sub.30, the D.sub.50, the D.sub.70, and the D.sub.90 satisfy (1) to (3) below.

[00001]$\begin{array}{cc}\left({\text{D}}_{50}{\text{- D}}_{10}\right)/{\text{D}}_{30}\le 0.6& \text{­­­(1)}\end{array}$

[00002]$\begin{array}{cc}\left({\text{D}}_{90}{\text{- D}}_{50}\right)/{\text{D}}_{70}\le 0.6& \text{­­­(2)}\end{array}$

[00003]

The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiTa.sub.2O.sub.6-based microwave dielectric ceramic material co-sintered at low temperature and its preparation method. Based on the low melting point characteristics of CuO and B.sub.2O.sub.3, and the radius of Cu.sup.2+ ions is similar to that of Ni.sup.2+ and Ta.sup.5+ ions, the chemical general formula of the invention is designed as xCuO-(1-x)NiO-[7.42y+(xy/14.33)]B.sub.2O.sub.3—Ta.sub.2O.sub.5, and the molar content of each component is adjusted from raw materials. The main crystalline phase of NiTa.sub.2O.sub.6 is synthesized at a lower pre-sintering temperature, and NiTa.sub.2O.sub.6-based ceramic material with low-temperature sintering characteristics and excellent microwave dielectric properties are directly synthesized at one time, which broadened the application range in LTCC field.