Provided are a positive electrode active material that can provide a nonaqueous electrolyte secondary battery having high energy density and excellent output characteristics, a nickel-manganese composite hydroxide as a precursor thereof, and methods for producing these. A nickel-manganese composite hydroxide is represented by General Formula (1): Ni.sub.xMn.sub.yM.sub.z(OH).sub.2+α and contains a secondary particle formed of a plurality of flocculated primary particles. The nickel-manganese composite hydroxide has a half width of a diffraction peak of a (001) plane of at least 0.35° and up to 0.50° and has a degree of sparsity/density represented by [(a void area within the secondary particle/a cross section of the secondary particle)×100](%) within a range of greater than 10% and up to 25%.

The present invention relates to a cathode active material for a lithium secondary battery, and more particularly, to a cathode active material for a lithium secondary battery, which includes a core portion and a shell portion surrounding the core portion, in which a total content of cobalt in the core portion and the shell portion is 5 to 12 mol %, and the content of cobalt in the core portion and the shell portion is adjusted to be within a predetermined range. In the cathode active material precursor and the cathode active material for a secondary battery prepared using the same according to the present invention, optimal capacity of a lithium secondary battery may be increased by adjusting the cobalt content in the particles of the cathode active material, and life characteristics may be enhanced by improving stability.

A nickel-based active material precursor for a lithium secondary battery includes: a secondary particle including a plurality of particulate structures, wherein each particulate structure includes a porous core portion and a shell portion, the shell portion including primary particles radially arranged on the porous core portion; and the secondary particle has a plurality of radial centers. When the nickel-based active material precursor is used, a nickel-based positive active material having a short lithium ion diffusion distance, in which intercalation and deintercalation of lithium are facilitated, may be obtained. A lithium secondary battery manufactured using the positive active material may exhibit enhanced lithium availability, and may exhibit enhanced capacity and lifespan due to suppression of crack formation in the active material during charging and discharging.

Provided is a precursor of transition metal oxide represented by chemical formula 1 below.

Ni.sub.aMn.sub.bCo.sub.1−(a+b+c+d)Zr.sub.cM.sub.d[OH.sub.(1-x)2-y]A.sub.(y/n)   [Chemical formula 1]

A process for preparing a cathode material of the form Li.sub.aMn.sub.1-x-y-zFe.sub.xCo.sub.yNi.sub.zO.sub.2-dCl.sub.d is provided. In addition, a Li.sub.aMn.sub.1-x-y-zFe.sub.xCo.sub.yNi.sub.zO.sub.2-dCl.sub.d cathode material for electrochemical systems is provided. Furthermore, a lithium or lithium-ion rechargeable electrochemical cell is provided, incorporating the Li.sub.aMn.sub.1-x-y-zFe.sub.xCo.sub.yNi.sub.zO.sub.2-dCl.sub.d cathode material in a positive electrode.

A positive active material for a rechargeable lithium battery includes a first positive active material including a secondary particle including at least two agglomerated primary particles, where at least one part of the primary particles has a radial arrangement structure, as well as a second positive active material having a monolith structure, wherein the first and second positive active materials may each include nickel-based positive active materials and the surface of the second positive active material is coated with a boron-containing compound. Further embodiments provide a method of preparing the positive active material, and a rechargeable lithium battery including a positive electrode including the positive active material.

To provide a cathode active material for a non-aqueous electrode rechargeable battery, with which it is possible to improve input/output characteristics, particularly by reducing resistance in a low SOC state in which DCIR increases, and to provide a manufacturing method for same. The cathode active material includes layered hexagonal crystal lithium nickel manganese composite oxide particles represented by the general formula (A): Li.sub.1+uNi.sub.xMn.sub.yCo.sub.zM.sub.tO.sub.2 (where 0≦u≦0.20, x+y+z+t=1, 0.30≦x ≦0.70, 0.10≦y≦0.55, 0≦z≦0.40, 0≦t≦0.10, and M is one or more elements selected from Al, Ti, V, Cr, Zr, Nb, Mo, and W), and further including Na, Mg, Ca and SO.sub.4, in which the total amount of Na, Mg and Ca is 0.01 to 0.1 mass %, the amount of SO.sub.4 is 0.1 to 1.0 mass %, and the ratio of the integrated intensity of the diffraction peak on plane (003) to that on plane (104) obtained by powder X-ray diffraction measurement using CuKα rays is 1.20 or greater.

Disclosed are a method for manufacturing a lithium secondary battery positive active material exhibiting a concentration gradient and a lithium secondary battery positive active material exhibiting a concentration gradient, manufactured by the method, and more particularly, a method for manufacturing a lithium secondary battery positive active material exhibiting a concentration gradient and a lithium secondary battery positive active material exhibiting a concentration gradient, manufactured by the method, the method being characterized by forming a barrier layer so as to maintain a concentration gradient layer even in case of thermal diffusion by a subsequent thermal treatment process.

The present application discloses a positive electrode active material, a positive electrode plate, a lithium-ion secondary battery, and an apparatus. The positive electrode active material satisfies a chemical formula Li.sub.1+x(Ni.sub.aCo.sub.bMn.sub.c).sub.1−dM.sub.dO.sub.2−yA.sub.y, wherein M is one or more selected from Zr, Sr, B, Ti, Mg, Sn and Al, A is one or more selected from S, N, F, Cl, Br and I, −0.01≤x≤0.2, 0.12≤b/c≤0.9, 0.002≤b×c/a.sup.2≤0.23, a+b+c=1, 0≤d≤0.1, and 0≤y≤0.2; and an interval particle size distribution curve of the positive electrode active material has a full width at half maximum D.sub.FW of from 4 μm to 8 μm. The positive electrode active material provided in the present application has relatively low cobalt content and relatively high cycle life and capacity performance.

A positive electrode active material precursor for a lithium secondary battery, in which the following requirements (1) and (2) are satisfied.

Requirement (1): In powder X-ray diffraction measurement using a CuKα ray, α/β that is a ratio of an integrated intensity α of a peak present within a range of a diffraction angle 2θ=19.2±1° to an integrated intensity β of a peak present within a range of a diffraction angle 2θ=33.5±1° is 3.0 or more and 5.8 or less.

Requirement (2): A 10% cumulative volume particle size D.sub.10 obtained from particle size distribution measurement is 2 μm or less.