Positive electrode active material for non-aqueous electrolyte secondary battery and method for manufacturing the same, positive electrode mixed material paste for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-12418041-B2
Application number	US-201716086746-A
Country	US
Kind code	B2
Filing date	Mar 22, 2017
Priority date	Mar 24, 2016
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

The present invention has an object to provide a positive electrode active material for a non-aqueous electrolyte secondary battery which can improve stability of a positive electrode mixed material paste when manufacturing the secondary battery and can increase the battery capacity and improve output characteristic of the secondary battery. A method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery includes mixing fired powder containing lithium-metal composite oxide having a crystal structure of a layered structure with water, and drying this mixture. The fired powder includes secondary particles formed by agglomeration of primary particles. Water is mixed thereto with an amount with which pH of a supernatant obtained after 5 g of the positive electrode active material is dispersed into 100 mL of pure water followed by statically leaving the dispersion solution for 10 minutes falls within a range of 11 to 11.9 at 25° C.

First claim

The invention claimed is:

1. A positive electrode active material for a non-aqueous electrolyte secondary battery, wherein
the positive electrode active material for a non-aqueous electrolyte secondary battery comprises a lithium-metal composite oxide powder having a crystal structure of a layered structure;
the lithium-metal composite oxide powder is represented by general formula (1): Li 8 Ni 1-x-y-z Co x Mn y M 1 z O 2 (where 0.05≤x≤0.35, 0≤y≤0.35, 0≤z≤0.10, and 0.95≤s≤1.50; and M 1 represents at least one element selected from V, Mg, Mo, Nb, Ti, W, and Al) and comprises secondary particles formed by agglomeration of primary particles thereof,
pH of a supernatant obtained after 5 g of the positive electrode active material is dispersed into 100 mL of pure water followed by statically leaving the resultant dispersion solution for a period of 10 minutes is at least 11.5 and up to 11.9 as measured at 25° C.;
an amount of excess LiOH is 0.05% by mass or more based on an entire mass of the positive electrode active material, and an amount of excess Li 2 CO 3 is 0.364% by mass or more based on the entire mass of the positive electrode active material,
a mass ratio of the excess LiOH to the excess Li 2 CO 3 (excess LiOH/excess Li 2 CO 3 ) quantified by a titration method is 0.277 or lower,
the mass ratio of the excess LiOH to the excess Li 2 CO 3 (excess LiOH/excess Li 2 CO 3 ) is 0.18 or higher,
the amount of the excess Li 2 CO 3 is 0.157×10 −2 g/m 2 or less with regard to a surface area of the positive electrode active material, and
a specific surface area of the positive electrode active material is at least 1 m 2 /g and up to 3.01 m 2 /g.

2. The positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein an average particle diameter thereof is in a range of at least 3 μm and up to 15 μm, and [(d90-d10)/average particle diameter] that is an indicator to show spread of the particle size distribution is 0.7 or smaller.

3. The positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein a ratio of an area occupied by a void measured in observation of a section of the lithium-metal composite oxide powder is at least 4.5% and up to 60% with regard to a sectional area of an entire lithium-metal composite oxide particle.

4. The positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the lithium-metal composite oxide powder is represented by general formula (2): Li 8 Ni 1-x-y-z-t Co x Mn y M 2 z W t O 2 , provided that 0.05≤x≤0.35, 0≤y≤0.35, 0≤z≤0.10, 0.95≤s≤1.50, 0.0001≤t≤0.03, and 0.0001≤z+t≤0.10; and M 2 represents at least one element selected from V, Mg, Mo, Nb, Ti, and Al.

5. A positive electrode mixed material paste for a non-aqueous electrolyte secondary battery, wherein the paste comprises the positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 .

6. A non-aqueous electrolyte secondary battery, wherein the battery has a positive electrode comprising the positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 .

7. The positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein a positive electrode mixed material paste which comprises the positive electrode active material satisfies the following viscosity stability requirement:
when the positive electrode mixed material paste is prepared by mixing 25.0 g of the positive electrode active material, 1.5 g of carbon powder as a conductive agent, 2.9 g of polyvinylidene fluoride (PVDF), and N-methyl-2-pyrrolidone (NMP), such that a viscosity of the prepared positive electrode mixed material paste falls within a range of 1.5 Pa·s to 2.5 Pa·s, and is immediately stored for 76 hours, a ratio of the viscosity measured after the 76-hour storage to the viscosity measured before the 76-hour storage (the viscosity after the 76-hour storage/the viscosity before the 76-hour storage) is 0.95 or less.

8. The positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , wherein the lithium-metal composite oxide powder is represented by general formula (2): Li 8 Ni 1-x-y-z Co x Mn y M 1 z O 2 (where 0.05≤x≤0.35, 0<y≤0.35, 0≤z≤0.10, and 0.95≤s≤1.50, and M 1 represents at least one element selected from V, Mg, Mo, Nb, Ti, W, and Al).

9. A method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1 , the method comprising:
mixing fired powder containing a lithium-metal composite oxide having a crystal structure of a layered structure with water; and
drying the resultant mixture obtained by the mixing, wherein
the fired powder is represented by general formula (1): Li 8 Ni 1-x-y-z Co x Mn y M 1 z O 2 (where 0.05≤x≤0.35, 0≤y≤0.35, 0≤z≤0.10, and 0.95≤s≤1.50; and M 1 represents at least one element selected from V, Mg, Mo, Nb, Ti, W, and Al) and comprises secondary particles formed by agglomeration of primary particles thereof, and
the water is mixed thereto with an amount with which pH of a supernatant obtained after 5 g of the obtained positive electrode active material is dispersed into 100 mL of pure water followed by statically leaving the resultant dispersion solution for a period of 10 minutes falls within a range of at least 11.5 and up to 11.9 as measured at 25° C.

10. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein at the time when the fired powder is mixed with water, the water is mixed by spraying in droplets having a size of 1 μm to 2,000 μm.

11. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein the water is mixed with the amount in a range of at least 1% by mass and up to 35% by mass with regard to the fired powder.

12. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein the water is mixed with the amount in a range of at least 0.003 g/m 2 and up to 0.025 g/m 2 with regard to the surface area of the fired powder.

13. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein the water is mixed with the amount in a range of at least 1% by mass to up to 6% by mass with regard to the fired powder.

14. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein an average particle diameter of the fired powder is in a range of at least 3 μm and up to 15 μm, and [(d90-d10)/average particle diameter] that is an indicator to show spread of the particle size distribution is 0.7 or smaller.

15. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein a ratio of the area occupied by a void measured by observation of a section of the fired powder is at least 4.5% and up to 60% with regard to an entire sectional area of the fired powder.

16. The method for manufacturing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 9 , wherein the drying is carried out at least 100° C. and up to 300° C.

17. The method for manufactur

Assignees

• Sumitomo Metal Mining Co

Inventors

• Okada Jiro
• Aida Taira
• Komukai Tetsufumi

Classifications

• H01M4/131

  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

• H01M4/0416

  involving impregnation with a solution, dispersion, paste or dry powder (H01M4/0438 takes precedence) · CPC title

• H01M4/366

  as layered products · CPC title

• H01M2004/028

  Positive electrodes · CPC title