Positive electrode active material for lithium secondary battery, method of preparing the positive electrode active material, positive electrode for lithium secondary battery including the positive electrode active material, and lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2024266529-A1
Application number	US-202318484768-A
Country	US
Kind code	A1
Filing date	Oct 11, 2023
Priority date	Jan 31, 2023
Publication date	Aug 8, 2024
Grant date	—

Abstract

Provided are a positive electrode active material for a lithium secondary battery, a method of preparing the positive electrode active material, and a lithium secondary battery including a positive electrode that includes the positive electrode active material, wherein the positive electrode active material includes large crystal secondary particles of a nickel-based lithium metal oxide which include a plurality of primary particles, wherein the large crystal secondary particles have a hollow structure having pores therein, the primary particles have a size of about 1 μm to about 4 μm, the large crystal secondary particles have a size of about 10 μm to about 18 μm, the positive electrode active material comprises a coating layer containing a cobalt compound which is on surfaces of the large crystal secondary particles of the nickel-based lithium metal oxide, and the large crystal secondary particles of the nickel-based lithium metal oxide are doped with molybdenum.

First claim

1 . A positive electrode active material for a lithium secondary battery, comprising:
large crystal secondary particles of a nickel-based lithium metal oxide which comprise a plurality of primary particles, wherein the large crystal secondary particles have a hollow structure having pores therein, the primary particles have a size of about 1 μm to about 4 μm, the large crystal secondary particles have a size of about 10 μm to about 18 μm, the positive electrode active material comprises a coating layer containing a cobalt compound which is on surfaces of the large crystal secondary particles of the nickel-based lithium metal oxide, and the large crystal secondary particles of the nickel-based lithium metal oxide are doped with molybdenum.

2 . The positive electrode active material as claimed in claim 1 , wherein a content of molybdenum is in a range of about 0.1 mol % to about 1.0 mol % with respect to a total content of 100 mol % of metals other than lithium in the positive electrode active material.

3 . The positive electrode active material as claimed in claim 1 , wherein at least one selected from surfaces and grain boundaries of the plurality of primary particles comprises the coating layer containing the cobalt compound.

4 . The positive electrode active material as claimed in claim 1 , wherein a content of the cobalt compound in the coating layer containing the cobalt compound is in a range of about 0.1 mol % to about 5.0 mol % with respect to a total content of the positive electrode active material.

5 . The positive electrode active material as claimed in claim 1 , wherein the coating layer containing the cobalt compound has a thickness of about 1 nm to about 50 nm.

6 . The positive electrode active material as claimed in claim 1 , wherein, in the coating layer containing the cobalt compound, the cobalt compound comprises cobalt oxide, lithium cobalt oxide, or a combination thereof.

7 . The positive electrode active layer as claimed in claim 6 , wherein the coating layer containing the cobalt compound further comprises at least one selected from boron, manganese, phosphorus, aluminum, zinc, zirconium, and titanium.

8 . The positive electrode active material as claimed in claim 1 , wherein the pores inside the positive electrode material have a size of about 2 μm to about 7 μm.

9 . The positive electrode active material as claimed in claim 1 , wherein the nickel-based lithium metal oxide is a compound represented by Formula 1 below:

wherein, in Formula 1, M 1 is at least one element selected from Co, Mn, and Al,
M 2 is at least one element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr),
0.95≤a≤1.1, 0.6≤(1-x-y)<1, 0≤x<0.4, 0≤y<0.4, and 0≤α 1 ≤0.1, with the proviso that x and y are not both 0.

10 . The positive electrode active material as claimed in claim 1 , wherein the nickel-based lithium metal oxide is a compound represented by Formula 2 below:

wherein, in Formula 2, M 3 is at least one element selected from Mn and Al,
M 4 is at least one element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr),
0.95≤a≤1.1, 0.6≤(1-x-y-z)<1, 0≤x<0.4, and 0≤y<0.4, 0≤z<0.4, 0≤α 1 ≤0.1, with the proviso that x, y, and z are not all 0.

11 . The positive electrode active material as claimed in claim 1 , wherein the primary particles have a size of about 2 μm to about 4 μm, and the secondary particles have a size of about 12 μm to about 18 μm.

12 . The positive electrode active material as claimed in claim 1 , wherein a peak intensity ratio (I (033) /I (104) ) of the positive electrode active material measured through X-ray diffraction analysis is in a range of about 1.2 to about 4.0, and an area ratio (A (003) /A (104) ) is in a range of about 1.1 to about 1.4.

13 . The positive electrode active material as claimed in claim 1 , wherein the large crystal secondary particles comprise one or two single crystal primary particle layers.

14 . A method of preparing a positive electrode active material for a lithium secondary battery, the method comprising:
mixing together a nickel precursor, at least one metal precursor selected from a precursor (M 1 ) and a precursor (M 2 ), and a basic solution, to obtain a mixture, performing a co-precipitation reaction of the mixture, and then drying the mixture to obtain a nickel-based metal precursor having pores therein; obtaining a mixture of the nickel-based metal precursor having pores therein and a lithium precursor; adding a molybdenum precursor to the mixture of the nickel-based metal precursor having pores therein and the lithium precursor and performing a primary heat treatment on the mixture; performing a disintegration process on a product subjected to the primary heat treatment, to obtain a product in a hollow secondary particle state; and adding a cobalt precursor to the product in the hollow secondary particle state to obtain a mixture and performing a secondary heat treatment on the mixture to prepare the positive electrode active material as claimed in claim 1 , wherein the primary heat treatment is performed at a higher temperature than the secondary heat treatment, the precursor (M 1 ) is at least one selected from a cobalt precursor, a manganese precursor, and an aluminum precursor, and the precursor (M 2 ) is a precursor comprising at least one element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr).

15 . The method as claimed in claim 14 , wherein a pore region inside the nickel-based metal precursor has a size of about 2 μm to about 7 μm.

16 . The method as claimed in claim 14 , wherein the cobalt precursor comprises Co(OH) 2 , CoOOH, CoO, Co 2 O 3 , Co 3 O 4 , Co(OCOCH 3 ) 2 ·4H 2 O, CoCl 2 , Co(NO 3 ) 2 ·6H 2 O, CoSO 4 , Co(SO 4 ) 2 ·7H 2 O, or combination thereof.

17 . The method as claimed in claim 14 , wherein the nickel-based metal precursor is a compound represented by Formula 3 below, a compound represented by Formula 4 below, or a combination thereof:

wherein, in Formula 3, M 1 is at least one element selected from Co, Mn, and Al,
M 2 is at least one element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr),
0.6≤(1-x-y)<1, 0≤x<0.4, and 0≤y<0.4, with the proviso that x and y are not both 0, and

wherein, in Formula 4, M 1 is at least one element selected from Co, Mn, and Al,
M 2 is at least one element selected from boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr),
0.6≤(1-x-y)<1, 0≤x<0.4, and 0≤y<0.4, with the proviso that x and y are not both 0.

18 . The method as

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kang Byungwuk
• You Yongchan
• Lee Jangwook
• Choi Seungyeon
• Kim Soohyeon

Classifications

• C01P2006/40

  Electric properties · CPC title

• C01P2004/04

  obtained by TEM, STEM, STM or AFM · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• C01G53/50

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• C01G53/42 Primary

  containing alkali metals, e.g. LiNiO2 · CPC title