Nickel manganese composite hydroxide, method for producing same, positive electrode active material for nonaqueous electrolyte secondary batteries, method for producing said positive electrode active material, and nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-2020052295-A1
Application number	US-201716344888-A
Country	US
Kind code	A1
Filing date	Oct 31, 2017
Priority date	Oct 31, 2016
Publication date	Feb 13, 2020
Grant date	—

Abstract

A positive electrode active material reduces an eluted lithium amount when used for a nonaqueous electrolyte secondary battery, and a nickel-manganese composite hydroxide as a precursor. A nickel-manganese composite hydroxide contains a secondary particle formed of a plurality of mutually flocculated primary particles and is represented by Formula (1): Nix1Mny1Mz1(OH)2+α (0.70≤x1≤0.95, 0.05≤y1≤0.30, x1+y1+z1=1.0, and 0≤α≤0.4 are satisfied; and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W). The nickel-manganese composite hydroxide has a manganese-rich layer from a particle surface to a particle inner part of the secondary particle. The manganese-rich layer is represented by Formula (2): Nix2Mny2Mz2(OH)2+α. The thickness of the manganese-rich layer is at least 5% and up to 20% of the radius of the secondary particle.

First claim

1 . A nickel-manganese composite hydroxide comprising a secondary particle formed of a plurality of mutually flocculated primary particles and represented by General Formula (1): Ni x1 Mn y1 M z1 (OH) 2+α (in the formula (1), 0.70≤x1≤0.95, 0.05≤y1≤0.30, x1+y1+z1=1.0, and 0≤α≤0.4 are satisfied; and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W), wherein
the nickel-manganese composite hydroxide has a manganese-rich layer from a particle surface to a particle inner part of the secondary particle,
the manganese-rich layer is represented by General Formula (2) below, and a thickness of the manganese-rich layer is at least 5% and up to 20% of a radius of the secondary particle:
Ni x2 Mn y2 M z2 (OH) 2+α   General Formula (2):

(in the formula (2), x2+z2=0 and y2=1 are satisfied or y2/(x2+z2)≥0.6 is satisfied; 0≤z2≤0.40, x2+y2+z2=1.0, and 0≤a≤0.4 are satisfied; and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W).

2 . The nickel-manganese composite hydroxide according to claim 1 , the nickel-manganese composite hydroxide has a volume average particle diameter (Mv) of at least 4 μm and up to 20 μm and [(D90−D10)/Mv] indicating a particle diameter variation index calculated from an accumulated 90 volume % diameter (D90), an accumulated 10 volume % diameter (D10), and the volume average particle diameter (Mv) of at least 0.60 in particle size distribution measured by laser diffraction scattering.

3 . The nickel-manganese composite hydroxide according to claim 1 , the nickel-manganese composite hydroxide has a tap density of at least 1.8 g/cm 3 and up to 3.2 g/cm 3 .

4 . A method for producing the nickel-manganese composite hydroxide as claimed in claim 1 , the method comprising:
generating particles of a nickel-manganese composite hydroxide by continuously supplying a first mixed aqueous solution containing at least a nickel salt and a manganese salt to a reaction aqueous solution to be subjected to neutralization crystallization, and collecting the particles by overflowing slurry containing the particles from a reaction tank; and forming the manganese-rich layer on surfaces of the particles by subjecting a reaction aqueous solution containing the collected particles and a second mixed aqueous solution having a molar ratio of Ni, Mn, and M similar to that in the manganese-rich layer to neutralization crystallization.

5 . The method for producing the nickel-manganese composite hydroxide according to claim 4 , wherein at the generating and the forming, an ammonia concentration of the reaction aqueous solution is adjusted to at least 5 g/L and up to 25 g/L.

6 . The method for producing the nickel-manganese composite hydroxide according to claim 4 , wherein at the generating and the forming, a temperature of the reaction aqueous solution is adjusted to a range of at least 35° C. and up to 60° C.

7 . The method for producing the nickel-manganese composite hydroxide according to claim 4 , wherein at the forming, a pH value measured with a liquid temperature of 25° C. as a basis of the reaction aqueous solution is adjusted to a range of at least 10.0 and up to 13.0.

8 . A positive electrode active material for a nonaqueous electrolyte secondary battery, the positive electrode active material comprising a lithium-nickel-manganese composite oxide containing a secondary particle formed of a plurality of mutually flocculated primary particles, represented by General Formula (3): Li 1+t Ni x3 Mn y3 M z3 O 2+β (in the formula (3), −0.05≤t≤0.5, 0.70≤x3≤0.95, 0.05≤y3≤0.30, x3+y3+z3=1.0, and 0≤3≤0.5 are satisfied; and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W), and having a hexagonal layered structure, wherein
the positive electrode active material has:
a degree of circularity of the secondary particle calculated by image analysis of at least 0.95,
a (003)-plane crystallite diameter by X-ray diffraction measurement of at least 160 nm and up to 300 nm; and
a lithium amount eluted to water when immersed in water of up to 0.2% by mass relative to the entire positive electrode active material.

9 . The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 8 , the positive electrode active material has a volume average particle diameter (Mv) of at least 4 μm and up to 20 μm and [(D90−D10)/Mv] indicating a particle diameter variation index calculated from an accumulated 90 volume % diameter (D90), an accumulated 10 volume % diameter (D10), and the volume average particle diameter (Mv) of at least 0.60 in particle size distribution measured by laser diffraction scattering.

10 . The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 8 , the positive electrode active material has a specific surface area of at least 0.20 m 2 /g and up to 0.70 m 2 /g.

11 . The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 8 the positive electrode active material has a tap density of at least 2.2 g/cm 3 and up to 3.6 g/cm 3 .

12 . A method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery, the positive electrode active material comprising a lithium-nickel-manganese composite oxide represented by General Formula (3): Li 1+t Ni x3 Mn y3 M z3 O 2+β (in the formula (3), −0.05≤t≤0.5, 0.70≤x3≤0.95, 0.05≤y3≤0.30, x3+y3+z3=1.0, and 0≤β≤0.5 are satisfied; and M is at least one element selected from Co, Al, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, Fe, and W) and having a hexagonal layered structure, the method comprising:
mixing the nickel-manganese composite hydroxide according to claim 1 and a lithium compound together to form a lithium mixture; and
firing the lithium mixture in an oxidative atmosphere at a temperature of at least 800° C. and up to 950° C. to obtain a lithium-nickel-manganese composite oxide.

13 . The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 12 , wherein a value obtained by dividing an accumulated 50 volume % diameter (D50) of the lithium-nickel-manganese composite oxide after the firing by an accumulated 50 volume % diameter (D50) of the nickel-manganese composite hydroxide before the firing is up to 1.2 in particle size distribution measured by laser diffraction scattering.

14 . A nonaqueous electrolyte secondary battery comprising a positive electrode containing the positive electrode active material according to claim 8 .

Assignees

• Sumitomo Metal Mining Co

Inventors

• Koshika Yuki
• KANEDA Haruki
• Ando Takaaki

Classifications

• C01P2004/84

  one phase coated with the other · CPC title

• C01P2002/70

  defined by measured X-ray, neutron or electron diffraction data · CPC title

• C01P2004/61

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

• C01P2004/32

  Spheres · CPC title

• C01P2004/51

  Particles with a specific particle size distribution · CPC title