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

Patent metadata

Field	Value
Publication number	US-11196048-B2
Application number	US-201716332087-A
Country	US
Kind code	B2
Filing date	Sep 13, 2017
Priority date	Sep 13, 2016
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

Provided is a positive electrode active material that has high output characteristics and battery capacity when used for a positive electrode of a nonaqueous electrolyte secondary battery and can inhibit gelation of positive electrode mixture paste. A method for producing the positive electrode active material is also provided. A positive electrode active material for a nonaqueous electrolyte secondary battery contains a lithium-nickel-cobalt-manganese composite oxide represented by General Formula (1): Li i+s Ni x Co y Mn z B t M1 u O 2+β and having a hexagonal layered crystal structure. The lithium-nickel-cobalt-manganese composite oxide contains a secondary particle formed of a plurality of flocculated primary particles and a boron compound containing lithium present at least on part of surfaces of the primary particles. A water-soluble Li amount present on the surfaces of the primary particles is up to 0.1% by mass relative to the entire amount of the positive electrode active material.

First claim

The invention claimed is:

1. A positive electrode active material for a nonaqueous electrolyte secondary battery, the positive electrode active material comprising:
a lithium-nickel-cobalt-manganese composite oxide represented by General Formula (1): Li 1+s Ni x Co y Mn z B t M1 u O 2+β (in Formula (1), M1 is an element other than Li, Ni, Co, Mn, and B; and −0.05≤s≤0.20, 0.1≤x≤0.5, 0.1≤y≤0.5, 0.1≤z≤0.5, x+y+z+u=1, 0.025≤t≤0.04, 0≤u≤0.1, and 0≤β≤0.5) and having a hexagonal layered crystal structure, wherein
the lithium-nickel-cobalt-manganese composite oxide contains a secondary particle formed of a plurality of flocculated primary particles and a boron compound containing lithium present at least on part of surfaces of the primary particles, and
a water-soluble Li amount present on the surfaces of the primary particles is up to 0.1% by mass relative to an entire amount of the positive electrode active material.

2. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the positive electrode active material has an average particle diameter of at least 3 μm and up to 20 μm.

3. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the primary particles have an average particle diameter of at least 0.2 μm and up to 1.0 μm.

4. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein [(d90−d10)/(an average particle diameter)] as an indicator indicating a spread of particle size distribution of the positive electrode active material is up to 0.60.

5. The positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 , wherein the secondary particle has a hollow structure having a hollow part therewithin.

6. A method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery, the positive electrode active material comprising a lithium-nickel-cobalt-manganese composite oxide represented by General Formula (1): Li 1+s Ni x Co y Mn z B t M1 u O 2+β (in Formula (1), M1 is an element other than Li, Ni, Co, Mn, and B; and −0.05≤s≤0.20, 0.1≤x≤0.5, 0.1≤y≤0.5, 0.1≤z≤0.5, x+y+z+u=1, 0.025≤t≤0.04, 0≤u≤0.1, and 0≤β≤0.5) and having a hexagonal layered crystal structure, the method comprising:
obtaining nickel-cobalt-manganese composite hydroxide particles represented by General Formula (2): Ni x Co y Mn z M2 u (OH) 2+α (in Formula (2), M2 is an element other than Li, Ni, Co, and Mn; 0.1≤x≤0.5, 0.1≤y≤0.5, 0.1≤z≤0.5, x+y+z+u=1, 0≤u≤0.1, and 0≤α≤0.5) by crystallization;
mixing a lithium compound with the nickel-cobalt-manganese composite hydroxide particles such that a ratio of number of atoms of lithium to a sum of numbers of atoms of metal elements other than lithium is at least 0.95 and up to 1.20 to obtain a lithium mixture;
firing the lithium mixture while being held in an oxidative atmosphere at a temperature of at least 800° C. and up to 1,000° C. for at least 5 hours and up to 20 hours to obtain lithium-nickel-cobalt-manganese composite oxide particles formed of a secondary particle formed of a plurality of flocculated primary particles;
mixing the lithium-nickel-cobalt-manganese composite oxide particles and a boron raw material together to obtain a boron mixture; and
thermally treating the boron mixture in an oxidative atmosphere at a temperature of at least 200° C. and up to 300° C. to form a boron compound containing lithium present at least on part of surfaces of the primary particles, wherein
at the thermally treating, thermal treatment is performed such that a water-soluble Li amount present on the surfaces of the primary particles after the thermal treatment is up to 0.1% by mass relative to an entire amount of the positive electrode active material.

7. The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 6 , wherein the boron raw material is at least one of boron oxide and an oxoacid of boron.

8. The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 7 , wherein the boron raw material is orthoboric acid.

9. The method for producing a positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 6 , further comprising crushing the lithium-nickel-cobalt-manganese composite oxide particles obtained at the firing.

10. A nonaqueous electrolyte secondary battery comprising:
a positive electrode;
a negative electrode;
a separator; and
a nonaqueous electrolyte,
the positive electrode containing the positive electrode active material for a nonaqueous electrolyte secondary battery according to claim 1 .

11. The method for producing the positive electrode active material for the nonaqueous electrolyte secondary battery according to claim 6 , wherein at the thermally treating, the thermal treatment is performed such that the water-soluble Li amount present on surfaces of the primary particles after the thermal treatment is up to 1.3 times the amount before the thermal treatment.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Yamauchi Mitsuru
• Komukai Tetsufumi

Classifications

• C01G53/82

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

• C01B35/12

  Borates {(C01B35/1063 takes precedence)} · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• C01P2004/61

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

• C01P2004/51

  Particles with a specific particle size distribution · CPC title