The present invention relates to a positive electrode active material with improved electrochemical properties and stability and a lithium secondary battery using a positive electrode comprising the same, wherein secondary particles formed by aggregation of a plurality of primary particles are provided as aggregates of primary particles in which a concentration gradient of the doping metal is formed from a grain boundary between the primary particles toward a center portion of the primary particle.

The present disclosure relates to a cathode additive of a lithium secondary battery, and a method for preparing the same. The cathode additive exhibits high irreversible capacity, and may be effectively applied to a battery using an anode material having high energy density. In one embodiment, the cathode additive includes a compound represented by the following Chemical Formula 1:
y(Li.sub.2Ni.sub.1-xM.sub.xO.sub.2)-z(Li.sub.6Co.sub.1-xM.sub.xO.sub.4)   [Chemical Formula 1]

A method of producing a positive electrode active material, the method includes: contacting first particles that contain a lithium transition metal composite oxide with a solution containing sodium ions to obtain second particles containing the lithium transition metal composite oxide and sodium element, wherein the lithium transition metal composite oxide has a layered structure and a composition ratio of a number of moles of nickel to a total number of moles of metals other than lithium in a range of from 0.7 to less than 1; mixing the second particles and a boron compound to obtain a mixture; and heat-treating the mixture at a temperature in a range of from 100° C. to 450° C.

The invention relates to improved particulate lithium nickel oxide materials which are useful as cathode materials in lithium secondary batteries, and methods of improving their safety.

Provided are processes for the production of particles for use as a precursor material for synthesis of Li-ion cathode active material of a lithium-ion cell comprising: a non-lithiated nickel oxide particle of the formula MO.sub.x wherein M comprises 80 at % Ni or greater and wherein x is 0.7 to 1.2, M optionally excluding boron in the MO.sub.x crystal structure; and a modifier oxide intermixed with, coated on, present within, or combinations thereof the non-lithiated nickel oxide particle, wherein the modifier oxide is associated with the non-lithiated nickel oxide such that a calcination at 500 degrees Celsius for 2 hours results in crystallite growth measured by XRD of 2 nanometers or less.

The present invention relates to a lithium composite oxide, a positive electrode active material for a lithium secondary battery including the lithium composite oxide, and a lithium secondary battery using a positive electrode including the positive electrode active material.

The present invention is to provide a cathode active material used for a lithium ion secondary battery which has a large charge-discharge capacity, and excels in charge-discharge cycle properties, output properties and productivity, and, a lithium ion secondary battery using the same. The cathode active material used for a lithium ion secondary battery comprises a lithium-transition metal composite oxide having an α-NaFeO.sub.2 type crystal structure and represented by the following formula (1); Li.sub.1+aNi.sub.bCo.sub.cM.sub.dO.sub.2+α, where, in the formula (1), M is at least one metal element other than Li, Ni and Co; and a, b, c, d and a are respectively numbers satisfying −0.04≤a≤0.04, 0.80≤b≤1.0, 0≤c≤0.06, b+c+d=1, and −0.2<α<0.2, and an a-axis lattice constant of the crystal structure is 2.878×10.sup.−10 m or more.

Provided is a method for producing a lithium transition metal oxide, comprising, A) mixing a lithium salt and a precursor, adding the mixture into a reactor for precalcination; the lithium salt has a particle size D50 of 10-20 μm and the precursor has a particle size D50 of 1-20 μm, and the precursor is one or more selected from transition metal oxyhydroxide, transition metal hydroxide and transition metal carbonate; and B) adding the product obtained from the precalcination into a fluidized bed reactor, subjecting to a first calcination and a second calcination to obtain the lithium transition metal oxide. Raw materials for the lithium transition metal oxide further includes a main-group metal compound containing oxygen, which is added in the precalcination, the first calcination or the second calcination; and the main-group metal compound containing oxygen has an average particle size of 10-100 nm. A fluidized bed reactor is also provided.

Nickelate cathode materials are provided, wherein said cathode material has an X-ray diffraction (XRD) pattern comprising a first peak from about 40.0-41.6 2Θ, and a second peak from about 62.6-63.0 2 Θ. Methods of preparing such cathode materials are also provided. Alkaline electrochemical cells comprising said cathode materials are also provided.

The cathode active material for a lithium secondary battery according to embodiments of the present invention includes lithium-transition metal composite oxide particles including a plurality of primary particles, and the lithium-transition metal composite oxide particles have a lithium-potassium-containing portion formed between the primary particles. Thereby, it is possible to improve life-span properties and capacity properties by preventing the layer structure deformation of the primary particles and removing residual lithium.