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

Patent metadata

Field	Value
Publication number	US-10497936-B2
Application number	US-201515539786-A
Country	US
Kind code	B2
Filing date	Dec 17, 2015
Priority date	Dec 26, 2014
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

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—Ni composite oxide particles represented by the formula: Li z Ni 1-x-y Co x M y O 2 and 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.

First claim

The invention claimed is:

1. A positive electrode active material for nonaqueous electrolyte secondary batteries, comprising a lithium-nickel composite oxide powder having a layered crystal structure composed of primary particles and secondary particles formed by aggregation of the primary particles, the positive electrode active material being represented by a general formula: Li z Ni 1-x-y Co x M y W a O 2+α , where 0≤x≤0.35, 0≤y≤0.35, 0.95≤z≤1.30, 0<a≤0.03, and 0≤α≤0.15 are satisfied, and M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al, wherein
lithium tungstate and a lithium compound other than lithium tungstate are present on a surface of the primary particles of the lithium-nickel composite oxide,
an amount of lithium contained in the lithium compound other than the lithium tungstate present on the surface of the primary particles of the lithium-nickel composite oxide is 0.01 to 0.05 mass % with respect to the total amount of the positive electrode active material, and
a content of sulfate radical in the positive electrode active material is 0.001 to 0.05 mass %.

2. The positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein
an amount of tungsten contained in the positive electrode active material is 0.05 to 2.0 at % with respect to the total number of atoms of Ni, Co, and M contained in the lithium-nickel composite oxide powder.

3. The positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein
the lithium tungstate is present on the surface of the primary particles of the lithium-nickel composite oxide as fine particles having a particle size of 1 to 500 nm.

4. The positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein
the lithium tungstate is present on the surface of the primary particles of the lithium-nickel composite oxide as a coating film having a film thickness of 1 to 200 nm.

5. The positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein
the lithium tungstate is present on the surface of the primary particles of the lithium-nickel composite oxide in both forms of fine particles having a particle size of 1 to 500 nm and a coating film having a film thickness of 1 to 200 nm.

6. The positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein
the content of sulfate radical is 0.001 to 0.02 mass %.

7. A nonaqueous electrolyte secondary battery comprising:
a positive electrode including the positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 .

Assignees

• Sumitomo Metal Mining Co

Inventors

• Kondo Kentaro
• Yokoyama Jun
• Furuichi Yuki
• Komukai Tetsufumi

Classifications

• H01M4/628

  Inhibitors, e.g. gassing inhibitors, corrosion inhibitors · CPC title

• C01P2002/20

  Two-dimensional structures · CPC title

• C01P2004/80

  Particles consisting of a mixture of two or more inorganic phases · CPC title

• C01P2004/50

  Agglomerated particles · CPC title

• H01M10/052

  Li-accumulators · CPC title