Provided are a positive electrode active material with which a nonaqueous electrolyte secondary battery having a high energy density can be obtained, a nickel-manganese composite hydroxide suitable as a precursor of the positive electrode active material, and production methods capable of easily producing these in an industrial scale. Provided is a nickel-manganese composite hydroxide represented by General Formula (1): Ni.sub.xMn.sub.yM.sub.z(OH).sub.2+α and containing 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 obtained by X-ray diffraction measurement of at least 0.10° and up to 0.40° and has a degree of sparsity/density represented by [(void area within secondary particle/cross section of secondary particle)×100](%) of at least 0.5% and up to 10%. Also provided is a production method of the nickel-manganese composite hydroxide.

The disclosure provides a method of manufacturing a uniform cathode material precursor, including steps of: (A) providing an acidic solution of co-precipitating cations including at least one co-precipitating cation; (B) mixing at least one basic solution with the acidic solution of co-precipitating cations to produce a co-precipitating colloid; (C) performing a nano-grinding process on the acidic solution of co-precipitating cations; and optionally (D) performing a hydrothermal aging process; wherein the step (C) is performed before and/or simultaneously with the step (B); and the optional step (D) is performed simultaneously with the step (B) and/or after the step (C); and wherein the step (B), the step (C) and the optional step (D) are performed continuously without washing and/or filtration post-processing.

Provided are an apparatus and a method for reaction for use in a co-precipitation reaction for preparing a catalyst or a cathode active material for a lithium secondary battery, which injects a raw material (a solution) at least between impellers according to the solution level in a vessel, thereby making a stirring speed uniform and, in particular, minimizing a concentration difference between solutions. The apparatus for the reaction may comprise: a reaction vessel; a stirring means provided inside the reaction vessel and having multistage impellers; and a raw material injecting means, comprising at least one injection nozzle connected to the reaction vessel, for injecting a raw material at least between impellers.

A method of manufacturing a secondary battery cathode material includes preparing Li.sub.2O powder by separating CO.sub.2 from Li.sub.2CO.sub.3 powder, forming a mixed powder by mixing the Li.sub.2O powder with nickel-cobalt-manganese (NCM) precursor powder, and firing the mixed powder using a rotary kiln.

This positive electrode active material for nonaqueous electrolyte secondary batteries contains: a lithium transition metal composite oxide having secondary particles, each of which is formed of aggregated primary particles; and a surface modification layer which is formed on the surface of each primary particle of the lithium transition metal composite oxide. The lithium transition metal composite oxide contains at least Al and 80% by mole or more of Ni relative to the total number of moles of the metal elements excluding Li; and the surface modification layer contains at least Ba, and at least one of Sr and Ca.

By a method including at least a spraying/mixing step of: mixing a precursor compound of a positive electrode active material with a lithium compound to prepare a mixture; and simultaneously spraying a spraying agent containing at least one element onto the mixture, there can be produced a positive electrode active material for non-aqueous electrolyte secondary batteries, which does not adversely affect battery properties of non-aqueous electrolyte secondary batteries, without reducing production efficiency.

It is possible to easily produce a positive electrode active material containing at least lithium and nickel, which can impart cycle property, particularly excellent cycle property under high voltage to non-aqueous electrolyte secondary batteries, by a method including at least, in this order: a step (1) of mixing a precursor compound containing at least nickel with a lithium compound in a non-solvent system to prepare a mixture; a step (2) of subjecting the mixture to preliminary calcination at 450° C. to 700° C. under a non-oxygen atmosphere; and a step (3) of subjecting the mixture after the preliminary calcination to main calcination under an oxygen atmosphere.

This positive electrode active material for a nonaqueous electrolyte secondary battery includes a lithium transition metal composite oxide that contains at least 80 mol % of Ni with respect to the total number of moles of metal elements excluding Li. B is present at least on the surfaces of the particles of the composite oxide. When particles having a particle diameter larger than a volume-based particle diameter of 70% (D70) are defined as first particles and particles having a particle diameter smaller than a volume-based particle diameter of 30% (D30) are defined as second particles, the molar fraction of B with respect to the total number of moles of metal elements excluding Li in the second particles is higher than the molar fraction of B with respect to the total number of moles of metal elements excluding Li in the first particles.

A process for synthesizing a material, includes: (a) providing a plurality of powders including at least one lithiated powder including lithium, at least one TM powder including, for more than 95.0% of its mass, a transition metal chosen from titanium; cobalt, manganese, nickel, niobium, tin, iron and mixtures thereof, and at least one chalcogen powder including, for more than 95.0% of its mass, a chalcogen element chosen from sulfur, selenium, tellurium and mixtures thereof, (b) preparing a particulate mixture by mixing all the powders of the plurality or by mixing one of the powders of the plurality with a milled material obtained by; milling a particulate assembly formed by mixing at least two of the other powders of the plurality, and (c) milling the particulate fixture to form the material.

A positive electrode and a secondary battery including the same is disclosed herein. In some embodiments, a positive electrode includes a positive electrode current collector and a positive electrode mixture containing a positive electrode active material disposed thereon, the positive electrode active material includes a lithium transition metal oxide powder represented by chemical formula 1,

Li.sub.aNi.sub.xCo.sub.yM.sub.zO.sub.2-wA.sub.w  (1) M is at least one selected from the group consisting of Mn, Ti, Mg, Al, Zr, Mn and Ni, A is an oxygen-substituted halogen, and 1.00≤a≤1.05, 0.1≤x≤0.8, 0.1≤y≤0.8, 0.01≤z≤0.4, and 0≤w≤0.001, the powder having large particles which are secondary particles having an average particle diameter (D50) of 7 μm to 17 μm, and small particles which are single particles having average particle diameter (D50) of 2 μm to 7 μm, weight ratio of large particles to small particles is 5:5 to 9:1, and the positive electrode mixture has a porosity of 22% to 35%.