Cathode active material for lithium secondary battery, method of preparing the same, cathode for lithium secondary battery including the same, and lithium secondary battery including cathode

Patent metadata

Field	Value
Publication number	US-2024322156-A1
Application number	US-202318497818-A
Country	US
Kind code	A1
Filing date	Oct 30, 2023
Priority date	Mar 24, 2023
Publication date	Sep 26, 2024
Grant date	—

Abstract

A cathode active material, a method of preparing the same, and a lithium secondary battery including a cathode including the same are provided. The cathode active material includes nickel-based lithium metal oxide monolithic particles, the nickel-based lithium metal oxide monolithic particles having an average size of about 1 μm to about 4 μm, and a cobalt compound-containing coating layer on surfaces of the nickel-based lithium metal oxide monolithic particles, wherein the nickel-based lithium metal oxide monolithic particles are doped with molybdenum.

First claim

What is claimed is:

1 . A cathode active material for a lithium secondary battery, the cathode active material comprising:
nickel-based lithium metal oxide monolithic particles, the nickel-based lithium metal oxide monolithic particles having an average size of about 1 μm to about 4 μm; and a cobalt compound-containing coating layer on surfaces of the nickel-based lithium metal oxide monolithic particles, wherein the nickel-based lithium metal oxide monolithic particles are doped with molybdenum.

2 . The cathode active material of claim 1 , wherein an amount of the molybdenum is in a range of at least about 0.1 mol % and at most about 1.0 mol % with respect to a total amount of metals other than lithium in the cathode active material.

3 . The cathode active material of claim 1 , wherein an amount of a cobalt compound in the cobalt compound-containing coating layer is in a range of about 0.1 mol % to about 5.0 mol % with respect to a total amount of the cathode active material.

4 . The cathode active material of claim 1 , wherein the cobalt compound-containing coating layer has a thickness of about 1 nm to about 50 nm.

5 . The cathode active material of claim 1 , wherein a cobalt compound in the cobalt compound-containing coating layer comprises cobalt oxide, lithium cobalt oxide,
or a combination thereof.

6 . The cathode active material of claim 5 , wherein the cobalt compound-containing coating layer further comprises at least one selected from among boron,
manganese, phosphorus, aluminum, zinc, zirconium, and titanium.

7 . The cathode active material of claim 1 , wherein the nickel-based lithium metal oxide monolithic particles are a compound represented by Formula 1:
Li a (Ni 1-x-y M1 x M2 y )O 2±α1   Formula 1

wherein, in Formula 1, M1 is at least one element selected from among Co, Mn, and Al,
M2 is at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr), and
0.95≤a≤1.1, 0.6≤(1-x-y)<1, 0≤x<0.4, 0≤y<0.4, and 0≤α1≤0.1, and
wherein a case where both x and y are 0 at the same time is excluded.

8 . The cathode active material of claim 1 , wherein the nickel-based lithium metal oxide monolithic particles are a compound represented by Formula 2:
Li a (Ni 1-x-y-z Co x M3 y M4 z )O 2±α1   Formula 2
wherein, in Formula 2, M3 is at least one element selected from among Mn and Al, M4 is at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr), and 0.95≤a≤1.1, 0.6≤(1-x-y-z)<1, 0≤x<0.4, 0≤y<0.4, 0≤z<0.4, and 0≤α1≤0.1, and wherein a case where all of x, y, and z are 0 at the same time is excluded.

9 . The cathode active material of claim 1 , wherein FWHM (003) /FWHM (104) of the cathode active material, as measured by X-ray diffraction analysis, is in a range of about 0.72 to about 0.79.

10 . A method of preparing a cathode active material for a lithium secondary battery, the method comprising:
mixing a nickel precursor, at least one selected from among an M1 precursor and an M2 precursor, and a basic solution to obtain a first mixture, and coprecipitating the first mixture in a coprecipitation reaction, followed by drying, to obtain a nickel-based metal precursor having a pore region with pores therein; mixing the nickel-based metal precursor having the pore region with the pores therein and a lithium precursor to obtain a second mixture; adding a molybdenum precursor to the second mixture and heating the second mixture with a primary heat treatment to obtain a first product; pulverizing the first product utilizing a pulverization process to obtain a second product in a form of small monolithic particles; and adding a cobalt precursor to the second product to obtain a third mixture, and heating the third mixture with a secondary heat treatment, wherein the primary heat treatment is performed at higher temperature than the secondary heat treatment, the M1 precursor is at least one selected from among a cobalt precursor, a manganese precursor, and an aluminum precursor, and the M2 precursor is a precursor containing at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr).

11 . The method of claim 10 , wherein the pore region inside the nickel-based metal precursor has a size of about 2 μm to about 7 μm.

12 . The method of claim 10 , 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 a combination thereof.

13 . The method of claim 10 , wherein the nickel-based metal precursor is a compound represented by Formula 3, a compound represented by Formula 4, or a combination thereof:
(Ni 1-x-y M1 x M2 y )(OH) 2   Formula 3
wherein, in Formula 3, M1 is at least one element selected from among Co, Mn, and Al, M2 is at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr), and 0.6≤(1-x-y)<1, 0≤x<0.4, and 0≤y<0.4, wherein a case where both x and y are 0 at the same time is excluded,
(Ni 1-x-y M1 x M2 y )O  Formula 4

wherein, in Formula 4, M1 is at least one element selected from among Co, Mn, and Al, M2 is at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr), and 0.6≤(1-x-y)<1, 0≤x<0.4, and 0≤y<0.4, and wherein a case where both x and y are 0 at the same time is excluded.

14 . The method of claim 10 , wherein the nickel-based metal precursor is a compound of Formula 5, a compound of Formula 6, or a combination thereof:
Ni 1-x-y-z Co x M3 y M4 z (OH) 2   Formula 5
wherein, in Formula 5, M3 is at least one element selected from among Mn and Al, M4 is at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr), and 0.6≤(1-x-y-z)<1, 0≤x<0.4, 0≤y<0.4, and 0≤z<0.4, wherein a case where all of x, y, and z are 0 at the same time is excluded,
(Ni 1-x-y-z Co x M3 y M4 z )O  Formula 6

wherein, in Formula 6, M3 is at least one element selected from among Mn and Al, M4 is at least one element selected from among boron (B), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), and zirconium (Zr), and 0.6≤(1-x-y-z)<1, 0≤x<0.4, 0≤y<0.4, and 0≤z<0.4, and wherein a case where all of x, y, and z are 0 at the same time is excluded.

15 . The method of claim 10 , wherein the nickel-based metal precursor and the lithium precursor are mixed such that a molar ratio of Li/Me (a metal other than Li) is at least about 0.9 and at most about 1.1.

16 . The method of claim 10 , wherein the lithium precursor comprises lithium hydroxide, lithium carbonate, lithium sulfate, lithium nitrate, or a combination thereof.

17 . The method of claim 10 , wherein the primary heat treatment is performed at about 800° C. to about 1200° C. in an oxidizing gas atmosphere.

18 . The m

Assignees

• Samsung Sdi Co Ltd

Inventors

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

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C01P2006/40

  Electric properties · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• H01M2004/028

  Positive electrodes · CPC title