Sumitomo Metal Mining Company, Ltd.

Kentaro Kondo

Jun Yokoyama

Tetsufumi Komukai

Yuki Furuichi

The cathode active material for a lithium ion secondary battery is produced from spherical particles made of lithium nickel cobalt composite oxide represented by general formula: LiNiCoMO(wherein M is at least one element selected from among Mn, V, Mg, W, Mo, Nb, Ti, and Al and x, y, and z satisfy 0<x≤0.35, 0≤y≤0.35, and 0.97≤z≤1.20, respectively) and having a volume average particle diameter MV in a range of preferably 8 to 30 μm, wherein an area ratio of a lithium compound unevenly distributed on surfaces of the particles in a SEM image is 5% or less. The spherical particles preferably have a crystallite diameter in a range of 50 to 200 Å as determined from a full width at half maximum, FWHM of diffraction peak of (003) plane obtained by X ray diffraction by using Sherrer formula.

Cathode active material for lithium ion secondary battery and method for producing same

Provided is a method for producing a positive electrode active material for nonaqueous electrolyte secondary batteries, including: a water-washing step of mixing, with water, Li&#x2014;Ni composite oxide particles represented by the formula: LiNiCoMOand composed of primary particles and secondary particles formed by aggregation of the primary particles to water-wash it, and performing solid-liquid separation to obtain a washed cake; a mixing step of mixing a W compound powder free from Li with the washed cake to obtain a W-containing mixture; and a heat treatment step of heating the W-containing mixture, the heat treatment step including: a first heat treatment step of heating the W-containing mixture to disperse W on the surface of the primary particles; and subsequently, a second heat treatment step of heating it at a higher temperature than in the first heat treatment step to form a lithium tungstate compound on the surface of the primary particles.

Method for producing positive electrode active material for nonaqueous electrolyte secondary battery

In one aspect, a method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery, includes mixing first lithium nickel composite oxide particles containing lithium tungstate and second lithium nickel composite oxide particles not containing lithium tungstate. The first lithium nickel composite oxide particles have a composition represented by LiNiCoMO, and include a core material containing secondary particles each corresponding to an aggregation of a plurality of primary particles, and the lithium tungstate existing on at least a part of a surface of the primary particles on a surface of and inside the first lithium nickel composite oxide particles. The second lithium nickel composite oxide particles have a composition represented by LiNiCoMO, and include secondary particles each corresponding to an aggregation of a plurality of primary particles.

Positive electrode active material for nonaqueous electrolyte secondary battery, method for producing the same, and nonaqueous electrolyte secondary battery

Positive electrode active material for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery using said positive electrode active material

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Niihama, Japan

Kentaro Kondo