Positive active material precursor for rechargeable lithium battery, positive active material for rechargeable lithium battery, method of preparing the positive active material, and rechargeable lithium battery including the positive active material

Patent metadata

Field	Value
Publication number	US-12438152-B2
Application number	US-202016985567-A
Country	US
Kind code	B2
Filing date	Aug 5, 2020
Priority date	Aug 8, 2019
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

An embodiment provides a positive active material precursor for a rechargeable lithium battery including: a nickel-based composite precursor including a secondary particle comprising a plurality of primary particles that are aggregated together, the nickel-based composite precursor having a central portion and a surface portion, and the central portion of the nickel-based composite precursor including a phosphate.

First claim

What is claimed is:

1. A positive active material precursor for a rechargeable lithium battery comprising:
a nickel-based composite precursor comprising a secondary particle comprising a plurality of primary particles that are aggregated together,
the nickel-based composite precursor having a central portion and a surface portion, and
the central portion of the nickel-based composite precursor comprising a phosphate between adjacent ones of the plurality of primary particles,
wherein the nickel-based composite precursor of the surface portion is represented by Chemical Formula 2,
a concentration of the phosphate in the central portion of the nickel-based composite hydroxide precursor is higher than a concentration of the phosphate in the surface portion:
Ni x Co y Mn z M 1-x-y-z (OH) 2   [Chemical Formula 2]

wherein, in Chemical Formula 2,
0.7≤x≤1, 0≤y≤0.5, 0≤z≤0.5, 0.5≤x+y+z≤1, and M is at least one selected from Mn, Ni, Co, Al, Fe, V, Ti, and Cr.

2. The positive active material precursor of claim 1 , wherein:
the surface portion of the nickel-based composite precursor comprises a first surface portion contacting the central portion of the nickel-based composite precursor and a second surface portion surrounding the first surface portion, and
at least one selected from the first surface portion and the second surface portion does not comprise phosphate.

3. The positive active material precursor of claim 1 , wherein the central portion of the nickel-based composite precursor has a volume of 20 volume % to 70 volume % relative to a total volume of the secondary particle.

4. A positive active material for a rechargeable lithium battery comprising:
a nickel-based composite oxide comprising a secondary particle comprising a plurality of primary particles that are aggregated together,
the nickel-based composite oxide having a central portion and a surface portion, and
the central portion comprising a lithium transition metal phosphate between adjacent ones of the plurality of primary particles,
wherein the nickel-based composite oxide of the surface portion is represented by Chemical Formula 1, and
a concentration of the lithium transition metal phosphate in the central portion of the nickel-based composite oxide is higher than a concentration of the lithium transition metal phosphate in the surface portion of the nickel-based composite oxide:
Li a Ni x Co y Mn z M 1-x-y-z O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1,
0.8≤a≤1.2, 0.7≤x≤1, 0≤y≤0.5, 0≤z≤0.5, 0.5≤x+y+z≤1, and M is at least one selected from Mn, Ni, Co, Al, Fe, V, Ti, and Cr.

5. The positive active material of claim 4 , wherein the central portion of the nickel-based composite oxide has a volume of 20 volume % to 70 volume % relative to a total volume of the secondary particle.

6. The positive active material of claim 4 , wherein the lithium transition metal phosphate is present at grain boundaries of the secondary particle of the nickel-based composite oxide or between adjacent ones of the plurality of the primary particles of the nickel-based composite oxide.

7. The positive active material of claim 4 , wherein the lithium transition metal phosphate is included in an amount in a range of 0.01 wt % to 2 wt % based on a total amount of the positive active material.

8. The positive active material of claim 4 , wherein the nickel-based composite oxide further comprises a coating layer comprising the lithium transition metal phosphate on the surface portion of the nickel-based composite oxide.

9. The positive active material of claim 8 , wherein the coating layer has a thickness of less than or equal to 3 μm.

10. A method of preparing a positive active material for a rechargeable lithium battery, the method of comprising:
preparing a mixed solution comprising a transition metal solution comprising a nickel raw material, a manganese raw material, a cobalt raw material, a phosphorus-containing compound including at least one selected from a phosphoric acid and a phosphate, and, optionally, further comprising a metal raw material,
introducing the mixed solution, a chelating agent, and a precipitating agent into a reactor to perform a co-precipitation method, at a stirring power of about 1.0 kW/m 3 to about 5.0 kW/m 3 , and then introducing the transition metal solution, and the chelating agent into the reactor to perform the co-precipitation method at the reduced stirring power and prepare a secondary particle precursor,
drying the secondary particle precursor to prepare a nickel-based composite precursor, and
mixing the nickel-based composite precursor and a lithium raw material and calcining the mixture to prepare the positive active material of claim 4 .

11. The method of claim 10 , wherein the phosphorus-containing compound comprises at least one selected from NH 4 H 2 PO 4 , H 3 PO 4 , and (NH 4 ) 2 HPO 4 .

12. The method of claim 10 , wherein the phosphorus-containing compound is mixed in a mole ratio in a range of about 0.01 mole to about 1 mole based on 100 moles of the nickel-based composite precursor.

13. A rechargeable lithium battery comprising:
a positive electrode comprising the positive active material of claim 4 ;
a negative electrode; and
an electrolyte.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Do-Yu

Classifications

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/0416

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/505

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