Nonaqueous electrolyte secondary battery positive electrode active material and method for producing same, and nonaqueous electrolyte secondary battery which uses positive electrode active material

Patent metadata

Field	Value
Publication number	US-11605815-B2
Application number	US-201816760208-A
Country	US
Kind code	B2
Filing date	Jul 31, 2018
Priority date	Oct 31, 2017
Publication date	Mar 14, 2023
Grant date	Mar 14, 2023

Abstract

The present invention provides a composite oxide that can achieve a high low-temperature output characteristic, a method for manufacturing the same, and a positive electrode active material in which the generation of soluble lithium is suppressed and a problem of gelation is not caused 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 porous 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, the specific surface area is 3.0 to 4.0 [m2/g], and the porosity is more than 50 to 80[%].

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 porous internal 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,
the lithium-metal composite oxide powder has a specific surface area of 3.0 to 4.0 [m 2 /g], and
the secondary particle has a porosity of more than 50 to 80[%].

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 100 to 160 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 0.50 [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.] at a time when 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 porous internal structure,
the lithium-metal composite oxide powder has a porosity of more than 50 to 80[%],
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 3.0 to 4.0 [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, and the metal composite hydroxide has a coarse density of more than 50 to 80[%]:
a preparing process (a) for producing a metal composite hydroxide, the preparing process of stirring water having a water surface in an oxidizing 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 aqueous solution to the water while the water is stirred; performing a crystallization treatment in a state where the reaction solution has a maintained pH of 11.0 to 12.5; repeating
a crystallization treatment in the reaction solution having a liquid surface in an inert atmosphere or in a non-oxidizing atmosphere having a controlled oxygen concentration of 0.2[% by volume] or less, and
a crystallization treatment in the reaction solution having a liquid surface in an oxidizing atmosphere having an oxygen concentration of more than 21[% by volume]; and
crystallizing a metal composite hydroxide having a controlled coarse density of more than 50 to 80[%].

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 [μm] 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 8 , wherein
the lithium raw material is lithium carbonate, lithium hydroxide, or a mixture of the lithium carbonate and the lithium hydroxide.

10. 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.

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).

Assignees

• Sumitomo Metal Mining Co

Inventors

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

Classifications

• C01G53/82

  Compounds containing nickel, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01P2006/22

  Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• C01P2006/90

  Other properties not specified above · CPC title

• C01P2006/40

  Electric properties · CPC title