Non-aqueous electrolyte secondary battery positive electrode active material, method for producing same, and non-aqueous electrolyte secondary battery which uses positive electrode active material

Patent metadata

Field	Value
Publication number	US-11784310-B2
Application number	US-201816760101-A
Country	US
Kind code	B2
Filing date	Jul 31, 2018
Priority date	Oct 31, 2017
Publication date	Oct 10, 2023
Grant date	Oct 10, 2023

Abstract

The present invention provides a lithium-nickel-manganese-cobalt composite oxide in which the reactivity between a lithium raw material and a metal composite hydroxide is improved so that a high low-temperature output characteristic can be achieved, a method for manufacturing the composite oxide, and a positive electrode active material and the like without causing a problem of gelation during the paste preparation. A positive electrode active material for non-aqueous electrolyte secondary batteries, including a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or a lithium-metal composite oxide powder including both the primary particles and the secondary particle. The secondary particle has a solid structure inside as a main inside structure, the slurry pH is 11.5 or less, the soluble lithium content rate is 0.5 [% by mass] or less, and the specific surface area is 1.0 to 2.0 [m 2 /g].

First claim

The invention claimed is:

1. A positive electrode active material for non-aqueous electrolyte secondary batteries, the positive electrode active material comprising:
a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or
a lithium-metal composite oxide powder including both the primary particles and the secondary particle, wherein
the secondary particle has a solid structure inside as a main inside structure,
a mixed slurry being a mixture of water and the lithium-metal composite oxide powder as a slurry solid body component has a pH of 11.5 or less at a time when the mixed slurry contains the lithium-metal composite oxide powder at a slurry concentration of 50 [g/L],
the lithium-metal composite oxide powder contains soluble lithium at a content rate of 0.5 [% by mass] or less, and
the lithium-metal composite oxide powder has a specific surface area of 1.0 to 2.0 [m 2 /g].

2. The positive electrode active material for non-aqueous electrolyte secondary batteries, according to claim 1 , wherein
the lithium-metal composite oxide powder is represented by a general formula: Li a (Ni 1−w−x Mn w Co x ) 1−y M y O 2 : (0.98≤a≤1.20, 0.01≤w≤0.50, 0.01≤x≤0.50, 0.01≤y≤0.10, where M is one or more of Mg, Al, Ti, Fe, Cu, Si, Zn, Mo).

3. The positive electrode active material for non-aqueous electrolyte secondary batteries, according to claim 1 , wherein
the lithium-metal composite oxide powder has a particle strength of 200 to 230 MPa.

4. A non-aqueous electrolyte secondary battery comprising
a positive electrode including the positive electrode active material for non-aqueous electrolyte secondary batteries according to claim 1 , wherein
ΔV −20[° C.] determined by a current rest method is 0.60 [V] or less at −20 [° C.].

5. A positive electrode mixture paste for non-aqueous electrolyte secondary batteries, the positive electrode mixture paste comprising:
a solid component; and
a solvent, wherein
the solid component contains the positive electrode active material for non-aqueous electrolyte secondary batteries according to claim 1 , and
the positive electrode mixture paste has a viscosity of 5,000 [mPa·s] or less at 20 [° C], wherein the viscosity is measured under the condition that the solid component and the solvent have a mass ratio of the solid component [g]/the solvent [g]=1.875.

6. A method for manufacturing a positive electrode active material for non-aqueous electrolyte secondary batteries, the method comprising:
a filtration and washing process (A) of washing a metal composite hydroxide with water, or with an alkali and then with water, and collecting a residual material of the metal composite hydroxide by a solid-liquid separation;
a drying process (B) of obtaining a dried material of the metal composite hydroxide by drying the residual material;
a mixing process (C) of forming a mixture of the dried material and a fine powder lithium compound having a maximum particle size of 10 [μm] or less; and
a firing process (D) of forming a positive electrode active material for non-aqueous electrolyte secondary batteries, the positive electrode active material including a lithium-metal composite oxide as a fired body by firing the mixture, wherein
a lithium-metal composite oxide powder is manufactured with the metal composite hydroxide containing nickel, manganese, and cobalt and the fine powder lithium compound having a maximum particle size of 10 [μm] or less as raw materials using a manufacturing process including the processes (A) to (D) in order described above,
the lithium-metal composite oxide powder includes a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt or includes both the primary particles and the secondary particle,
the secondary particle has a solid structure inside as a main inside structure,
a slurry has a pH of 11.5 or less at a time when a slurry concentration is 50 [g/L],
the lithium-metal composite oxide powder contains 0.5 [% by mass] of soluble lithium, and
the lithium-metal composite oxide powder has a specific surface area of 1.0 to 2.0 [m 2 /g].

7. The method for manufacturing a positive electrode active material for non-aqueous electrolyte secondary batteries, according to claim 6 , wherein
the metal composite hydroxide is produced by a preparing process (a) described below:

a preparing process (a) for producing a metal composite hydroxide, the preparing process of stirring water having a water surface in an inert atmosphere and having a maintained temperature of 40 to 60 [° C]; forming a reaction solution by adding a nickel-manganese-cobalt mixed solution, ammonia water, and an alkaline solution to the water while the water is stirred; and crystallizing a metal compound hydroxide by promoting a crystallization reaction in a state where the reaction solution has a maintained pH of 11.0 to 12.5.

8. The method for manufacturing a positive electrode active material for non-aqueous electrolyte secondary batteries, according to claim 6 , wherein
a lithium raw material of the fine powder lithium compound, the lithium raw material before pulverized is a lithium compound powder having a maximum particle size of 100 [μtm] or more and an average particle size of 50 [μm] or more.

9. The method for manufacturing a positive electrode active material for non-aqueous electrolyte secondary batteries, according to claim 6 , wherein
the fine powder lithium compound has a maximum particle size of 10 [μm] or less and an average particle size of 5.0 [μm] or less, and
the fine powder lithium compound is formed using a pulverizing process (p) described below:
a pulverizing process (p) of producing a fine powder lithium compound having a maximum particle size of 10 [μm] or less and an average particle size of 5.0 [μm] or less by pulverizing a lithium compound powder being a lithium raw material having a maximum particle size of 100 [μm] or more and an average particle size of 50 [μm] or more.

10. The method for manufacturing a positive electrode active material for non- aqueous electrolyte secondary batteries, according to claim 8 , wherein
the lithium raw material is lithium carbonate, lithium hydroxide, or a mixture of the lithium carbonate and the lithium hydroxide.

11. The method for manufacturing a positive electrode active material for non-aqueous electrolyte secondary batteries, according to claim 6 , wherein
the lithium-metal composite oxide powder is represented by a general formula: Li a (Ni 1-w-x Mn w Co x ) 1-y M y O 2 : (0.98<a<1.20, 0.01<w<0.50, 0.01<x<0.50, 0.01<y<0.10, where M is one or more of Mg, Al, Ti, Fe, Cu, Si, Zn, Mo).

12. A method for evaluating a characteristic of a positive electrode active material for non-aqueous electrolyte secondary batteries according to claim 1 ,
the characteristic being a “slurry pH” indicating a pH of a slurry containing water and the positive electrode active material as a solid body component, the method comprising:
adding the positive electrode active material to the water so that the slurry contains the positive electrode active material at a concentration of 50 [g/L];
maintaining a state where the slurry is stirred for 30 minutes; and
obtaining the slurry pH by measuring the pH of the slurry with a “pH meter” in the state where the slurry is stirred.

13. A method for evaluating a characteristic of a positive electrode active material for non-aqueous electrolyte secondary batteries according to claim 1 ,
the positive electrode active material for non-aqueous electrolyte seco

Assignees

• Sumitomo Metal Mining Co

Inventors

• Oshita Hiroko
• Ryoshi Kazuomi
• Aida Taira
• Yamaji Koji
• Okada Jiro

Classifications

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M4/0471

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