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-11056681-B2
Application number	US-202017007707-A
Country	US
Kind code	B2
Filing date	Aug 31, 2020
Priority date	Apr 24, 2015
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

Provided is a method for producing the positive electrode active material for nonaqueous electrolyte secondary batteries, including a first step of mixing a Li-metal composite oxide powder which is represented by the general formula: LizNi1-x-yCoxMyO2 (where 0≤x≤0.35, 0≤y≤0.35, and 0.97≤z≤1.30 are satisfied, and M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al) and constituted by primary particles and secondary particles, to an alkaline solution with a W compound dissolved therein, and immersing a resulting mixture, followed by solid-liquid separation, to obtain a W mixture with W uniformly dispersed on the surface of the primary particles of the composite oxide, and a second step of heat-treating the W mixture to thereby form a compound containing W and Li on the surface of the primary particles of the composite oxide powder.

First claim

What is claimed is:

1. A method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries, comprising:
a first step of mixing a lithium-metal composite oxide powder which is represented by a general formula: Li z Ni 1-x-y Co x M y O 2 (where 0≤x≤0.35, 0≤y≤0.35, and 0.95≤z≤1.30 are satisfied, and M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al) and has a layered crystal structure constituted by primary particles and secondary particles formed by aggregation of the primary particles, to an alkaline solution with a tungsten compound dissolved therein at a tungsten concentration of 0.1 to 2 mol/L so that a solid-liquid ratio of the lithium-metal composite oxide powder to an amount of water in the alkaline solution falls within a range of 200 to 2500 g/L, and immersing a resulting mixture, followed by solid-liquid separation, to obtain a tungsten-containing mixture in which an amount of tungsten contained therein is controlled and tungsten is uniformly dispersed on a surface of the primary particles of the lithium-metal composite oxide; and
a second step of subjecting the tungsten-containing mixture to heat treatment to thereby form a compound containing tungsten and lithium on the surface of the primary particles of the lithium-metal composite oxide.

2. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , further comprising a water washing step of washing the lithium-metal composite oxide powder with water, before the first step is performed.

3. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 2 , wherein the tungsten-containing mixture contains tungsten in an amount of 3.0 at % or less with respect to a total number of atoms of Ni, Co and M contained in the lithium-metal composite oxide powder used in the mixing.

4. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 3 , wherein the alkaline solution with the tungsten compound dissolved therein has a tungsten concentration of 0.05 to 2 mol/L.

5. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 4 , wherein the alkaline solution is made by dissolving a tungsten compound in an aqueous lithium hydroxide solution.

6. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the mixing of the alkaline solution with the tungsten compound dissolved therein with the lithium-metal composite oxide powder is performed in the alkaline solution of the tungsten compound as a liquid and at a temperature of 50° C. or less.

7. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the heat treatment of the second step is performed in an oxygen atmosphere or a vacuum atmosphere at 100 to 600° C.

8. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the tungsten-containing mixture contains tungsten in an amount of 3.0 at % or less with respect to a total number of atoms of Ni, Co and M contained in the lithium-metal composite oxide powder used in the mixing.

9. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the alkaline solution with the tungsten compound dissolved therein has a tungsten concentration of 0.05 to 2 mol/L.

10. The method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the alkaline solution is made by dissolving a tungsten compound in an aqueous lithium hydroxide solution.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Furuichi Yuki
• Komukai Tetsufumi
• Toya Hiroyuki

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/366

  as layered products · CPC title