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

Patent metadata

Field	Value
Publication number	US-2018315997-A1
Application number	US-201715582968-A
Country	US
Kind code	A1
Filing date	May 1, 2017
Priority date	May 1, 2017
Publication date	Nov 1, 2018
Grant date	—

Abstract

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 Li z1 Ni 1-x1-y1 Co x1 M 1 y1 O 2 , 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 Li z2 Ni 1-x2-y2 Co x2 M 2 y2 O 2 , and include secondary particles each corresponding to an aggregation of a plurality of primary particles.

First claim

1 . A method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery, the method comprising mixing first lithium nickel composite oxide particles containing lithium tungstate and second lithium nickel composite oxide particles not containing lithium tungstate, wherein
the first lithium nickel composite oxide particles have a composition represented by Li z1 Ni 1-x1-y1 Co x1 M 1 y1 O 2 (where 0≤x1≤0.35, 0≤y1≤0.35, 0.95≤z1≤1.15, and M 1 is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), 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, and the second lithium nickel composite oxide particles have a composition represented by Li z2 Ni 1-x2-y2 Co x2 M 2 y2 O 2 (where 0≤x2≤0.35, 0≤y2≤0.35, 0.95≤z2≤1.15, and M 2 is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), and include secondary particles each corresponding to an aggregation of a plurality of primary particles.

2 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the second lithium nickel composite oxide particles are washed with water before the mixing.

3 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 2 , wherein in the washing with water, slurry has a concentration of 500 g/L or higher and 2,500 g/L or lower.

4 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the amount of lithium contained in a lithium compound other than the lithium tungstate existing on the surface of the primary particles on a surface of and inside both the first lithium nickel composite oxide particles and the second lithium nickel composite oxide particles is 0.05% by mass or less relative to the total amount of the positive electrode active material.

5 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the first lithium nickel composite oxide particles and the second lithium nickel composite oxide particles are mixed so that the positive electrode active material contains the first lithium nickel composite oxide particles by 10% by mass or more relative to the total amount of the positive electrode active material.

6 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the first lithium nickel composite oxide particles and the second lithium nickel composite oxide particles are mixed so that the first lithium nickel composite oxide particles contain tungsten by 0.03 at % or more and 2.5 at % or less relative to the total number of atoms of Ni, Co, and M contained in the positive electrode active material.

7 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , the method further comprising: before the mixing, preparing a tungsten mixture containing
a base material whose composition is represented by Li z3 Ni 1-x3-y3 Co x3 M 1 y3 O 2 (where 0.00≤x3≤0.35, 0.00≤y3≤0.35, 0.95≤z3≤1.20, and M 1 is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al) and that includes secondary particles each corresponding to an aggregation of a plurality of primary particles, water of 2% by mass or more relative to the total amount of the base material, and a tungsten compound or a tungsten compound and a lithium compound not containing a tungsten; and obtaining the first lithium nickel composite oxide particles by performing heat treatment on the obtained tungsten mixture to form the lithium tungstate on the surface of the primary particles on a surface of and inside the base material, wherein in the tungsten mixture, a molar ratio of the total amount of lithium contained in the water and the tungsten compound or in the water, the tungsten compound, and the lithium compound relative to the total amount of contained tungsten is 5 or lower.

8 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 7 , wherein the amount of lithium contained in the lithium compound other than the lithium tungstate existing on the surface of the primary particles on the surface of and inside the first lithium nickel composite oxide particles is 0.05% by mass or less relative to the first lithium nickel composite oxide particles.

9 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 7 , the method comprising:
before the heat treatment, washing the base material with water by mixing the base material and water to form slurry; and separating the washed base material into a solid and a liquid.

10 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 9 , wherein the slurry formed by mixing the base material and water has a concentration of 500 g/L or higher and 2,500 g/L or lower.

11 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 9 , wherein the water content of a washed cake obtained when the base material washed with water is separated into the solid and the liquid is controlled to be in a range of 3.0% by mass or more and 15.0% by mass or less.

12 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 7 , wherein the tungsten compound contains at least one of tungsten oxide (WO 3 ), tungstic acid (WO 3 .H 2 O), Li 2 WO 4 , Li 4 WO 5 , and Li 6 W 2 O 9 .

13 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 7 , wherein the heat treatment is performed at 100° C. or higher and 600° C. or lower.

14 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 7 , wherein the amount of tungsten contained in the tungsten compound is 0.05 at % or more and 3.0 at % or less relative to the total number of atoms of Ni, Co, and M contained in the base material.

15 . A positive electrode active material for a nonaqueous electrolyte secondary battery, the positive electrode active material comprising first lithium nickel composite oxide particles containing lithium tungstate and second lithium nickel composite oxide particles not containing lithium tungstate, wherein
the first lithium nickel composite oxide particles have a composition represented by Li z1 Ni 1-x1-y1 Co x1 M 1 y1 O 2 (where 0≤x1≤0.35, 0≤y1≤0.35, 0.95≤z1≤1.15, and M 1 is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, and Al), 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, and the second lithium nickel composite oxide particles have a composition represented by Li z2 Ni 1-x2-y2 Co x2 M 2 y2 O 2 (where 0≤x2≤0.35, 0≤y2≤

Assignees

• Sumitomo Metal Mining Co

Inventors

• Kondo Kentaro
• Yokoyama Jun
• Furuichi Yuki

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/62

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

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title