The present disclosure relates to the field of cathode materials, and provides a cathode material and a preparation method thereof as well as a lithium-ion secondary battery, wherein the cathode material comprises: a secondary particle comprising a plurality of primary particles, wherein the primary particles contain an active substance having a chemical general formula of LibNixCoyMzNwO2, where 0.95≤b≤1.05, 0.8≤x<1, 0<y+z≤0.2, x+y+z=1, and 0.0001≤w≤0.003; M is selected from at least one of Mn and Al; N is a metal and a coating layer, which comprises a first coating laver and a second coating laver, wherein the first coating laver is formed on the surface of the primary particles, the second coating laver is formed on the surface of the secondary particles, and both the first coating layer and the second coating laver contain a phosphate compound.

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.

The invention relates to improved particulate lithium nickel oxide materials which are useful as cathode materials in lithium secondary batteries. The invention also provides processes for preparing such lithium nickel oxide materials, and electrodes and cells comprising the materials.

A positive electrode active material for an all-solid-state lithium-ion battery composed of particles containing crystals of a lithium metal composite oxide, wherein the particles have a layered structure and contain at least Li and a transition metal, and in powder x-ray diffraction measurement using CuKα rays, a ratio I.sub.003/I.sub.004 of an integrated intensity I.sub.104 of a diffraction peak in a range of 2θ=44.4±1° to an integrated intensity I.sub.003 of a diffraction peak in a range of 2θ=18.5±1° exceeds 1.23, and wherein a press density A when the positive electrode active material for an all-solid-state lithium-ion battery is compressed at a pressure of 45 MPa is 2.90 g/cm.sup.3 or more.

Described herein are low or no-cobalt materials useful as electrode active materials in a cathode for lithium or lithium-ion batteries. For example, compositions of matter are described herein, such as electrode active materials that can be incorporated into an electrode, such as a cathode. The disclosed electrode active materials exhibit high specific energy and voltage, and can also exhibit high rate capability and/or long operational lifetime.

The cathode active material for a lithium secondary battery according to embodiments of the present invention includes a lithium-transition metal composite oxide particle including a plurality of primary particles, and the lithium-transition metal composite oxide particle includes a lithium-sulfur-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.

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 cathode active material for a secondary battery using a non-aqueous electrolyte includes nickel-rich lithium transition-metal oxide, exhibits a hard X-ray photoelectron spectroscopy (HAXPES) peak of 1,560 to 1,565 eV in binding energy from an Al-rich layer, using a photon energy of 6 KeV, and with respect to the mean particle diameter r of the lithium transition-metal oxide particle, the Al concentration is approximately constant within 0.35r of the center.

A positive active material for a rechargeable lithium battery, a preparing method thereof, and a rechargeable lithium battery including the same are provided. The positive active material for a rechargeable lithium battery includes a first positive active material including a first lithium nickel-based composite oxide and including secondary particles formed by aggregation of a plurality of primary particles and a cobalt coating portion on the surface of the secondary particles; and a second positive active material including a second lithium nickel-based composite oxide and including individual particles and a cobalt coating portion on the surface of the individual particles, wherein the second positive active material has an uneven surface having concavo-convex features and an even surface that is substantially flat.

A cathode active material for a lithium secondary battery comprises lithium-nickel composite metal oxide particles, each of which has a secondary particle structure in which primary particles are aggregated. The lithium-nickel composite metal oxide particles include a first element including at least one element selected from the group consisting of B, Al, Si, Ti, V, Mn, Fe, Co, Cu, Zn, Zr, Mo and W, and a second element having an ionic radius of 80 pm or more. The second element is different from nickel and the first element. The second element is present on an outer surface of the secondary particle, at grain boundaries between the primary particles and at an inside of the primary particles.