Composite cathode active material, cathode and lithium battery each including the same, and method of preparing composite cathode active material

Patent metadata

Field	Value
Publication number	US-2020136126-A1
Application number	US-201916504747-A
Country	US
Kind code	A1
Filing date	Jul 8, 2019
Priority date	Oct 25, 2018
Publication date	Apr 30, 2020
Grant date	—

Abstract

A composite cathode active material includes a secondary particle; and a coating on a surface of the secondary particle, wherein the secondary particle comprises a plurality of primary particles, and the plurality of primary particles include a lithium nickel transition metal oxide having a layered crystal structure; and a grain boundary between primary particles of the plurality of primary particles, the grain boundary including a lithium metal oxide having a crystal structure different from the lithium nickel transition metal oxide having a layered crystal structure, wherein the coating on the surface of the secondary particle includes a metal oxide including cobalt, and a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof

First claim

What is claimed is:

1 . A composite cathode active material comprising:
a secondary particle; a coating on a surface of the secondary particle,
wherein the secondary particle comprises a plurality of primary particles, and
wherein the plurality of primary particles comprise a lithium nickel transition metal oxide having a layered crystal structure; and
a grain boundary between primary particles of the plurality of primary particles, the grain boundary comprising a lithium metal oxide having a crystal structure different from the lithium nickel transition metal oxide having a layered crystal structure and represented by Formula 1, wherein the coating on the surface of the secondary particle comprises
a metal oxide including cobalt, and a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof,
Li a M1 b O c   Formula 1

wherein, in Formula 1, M1 is zirconium, manganese, silicon, molybdenum, palladium, cobalt, nickel, titanium, tin, iridium, platinum, aluminum, ruthenium, or a combination thereof, and wherein 1.9≤a≤4, 0.9≤b≤1.1, and 2.9≤c≤4.

2 . The composite cathode active material of claim 1 , wherein the lithium metal oxide represented by Formula 1 has a monoclinic crystal structure.

3 . The composite cathode active material of claim 1 , wherein the lithium metal oxide represented by Formula 1 comprises Li 2 ZrO 3 , Li 2 TiO 3 , Li 4 SiO 4 , Li 2 SiO 3 , or a combination thereof.

4 . The composite cathode active material of claim 1 , wherein the metal oxide comprising cobalt, and the at least one selected from a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof comprises a first metal oxide having a spinel structure, a second metal oxide having a layered structure, or a combination thereof.

5 . The composite cathode active material of claim 1 , wherein the metal oxide comprising cobalt is a metal oxide represented by Formula 2:
Li x Co a Me b O c   Formula 2
wherein, in Formula 2, Me is a Group 2 element, a Group 12 element, and a Group 13 element, or a combination thereof, and 0≤x≤1.1, 0<a≤3, 0<b≤3, and 1≤c≤4.1.

6 . The composite cathode active material of claim 1 , wherein the metal oxide comprising cobalt, and the at least one selected from a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof comprises a combination of i) at least one of Co 3 O 4 and Li x CoO 2 wherein 0<x≤1.5, and ii) MgO.

7 . The composite cathode active material of claim 1 , wherein the metal oxide comprising cobalt, and the at least one selected from a Group 2 element, a Group 12 element, a Group 13 element, or a combination thereof comprises a mixture of Co 3 O 4 and MgO, a Co 3 O 4 .MgO composite, a mixture of LiCoO 2 and MgO, a LiCoO 2 .MgO composite, a mixture of LiCoO 2 , Co 3 O 4 , and MgO, or a LiCoO 2 .Co 3 O 4 .MgO composite.

8 . The composite cathode active material of claim 1 , wherein a concentration of the Co and the Group 2 element, Group 12 element, Group 13 element, or combination thereof in the coating is greater than a concentration of the Co and the Group 2 element, Group 12 element, Group 13 element, or combination thereof in the secondary particle.

9 . The composite cathode active material of claim 1 , wherein, in the coating, a concentration of the Co and the Group 2 element, Group 12 element, Group 13 element, or a combination thereof increases in a direction away from the surface of the secondary particle.

10 . The composite cathode active material of claim 1 , wherein the metal oxide comprises Li x Co a Mg b O 4 , Li x Co a Ga b O 4 , Li x Co a Ca b O 4 , Li x Co a Ba b O 4 , Li x Co a Al b O 4 , or Li x Co a Zn b O 4 , wherein 1≤x≤1.1, 0<a<2, 0<b<2, and 0<a+b≤2.

11 . The composite cathode active material of claim 1 , wherein a particle comprising the lithium nickel transition metal oxide having a layered crystal structure comprises MgAl 2 O 4 .

12 . The composite cathode active material of claim 1 ,
wherein the lithium nickel transition metal oxide having a layered crystal structure has a rock-salt layered crystal structure and belongs to an R-3m space group, and wherein the metal oxide of the coating is a lithium cobalt composite oxide, and the lithium cobalt composite oxide belongs to an Fd-3m space group.

13 . The composite cathode active material of claim 1 , wherein the coating has a thickness of 1 micrometer or less.

14 . The composite cathode active material of claim 1 , wherein the lithium nickel transition metal oxide having a layered crystal structure comprises Al, Zr, or a combination thereof.

15 . The composite cathode active material of claim 1 , wherein the lithium nickel transition metal oxide having a layered crystal structure is represented by Formula 3:
Li a M2O 2-α X α   Formula 3
wherein, in Formula 3, 0.9≤a≤1.1, 0≤α<2, and M2 comprises nickel and at least two elements of Groups 2 to 13 except for Ni, X is F, Cl, Br, S, or P, and a nickel content in M2 ranges from about 70 mole percent to less than about 100 mole percent, based on a total content of M2.

16 . The composite cathode active material of claim 1 , wherein the lithium nickel transition metal oxide having a layered crystal structure is represented by Formula 4 below:
Li a Ni b M2 c M3 d M4 e O 2-α X α   Formula 4
wherein, in Formula 4, 0.9≤a≤1.1, 0.7<b<1, 0<c<0.3, 0<d<0.3, 0≤e<0.1, b+c+d+e=1, and 0≤α<2, M2, M3, and M4 are different from one another and are each independently Co, Mn, Al, Zr, Re, V, Cr, Fe, B, Ru, Ti, Nb, Mo, Mg, or Pt, and X is F, Cl, Br, S, or P.

17 . The composite cathode active material of claim 1 , wherein the lithium nickel transition metal oxide having a layered crystal structure is a compound represented by Formula 5, a compound represented by Formula 6, or a combination thereof:
Li a Ni b CO c Mn d M5 e O 2-α X α ,  Formula 5
Li a Ni b CO c Al d M5 e O 2-α X α   Formula 6
wherein, in Formulae 5 and 6, a, b, c, d, and e, are each independently 0.9≤a≤1.1, 0.7<b<1, 0<c<0.1, 0<d<0.1, 0≤e<0.01, b+c+d+e=1, and 0≤α<2, M5 in Formulae 5 and 6 are each independently Zr, Al, V, Cr, Fe, Re, B, Ru, Ti, Nb, Mo, Mg, or Pt, and X is F, Cl, Br, S, or P.

18 . The composite cathode active material of claim 1 , wherein the lithium nickel transition metal oxide having a layered crystal structure is represented by Formula 7:
a Li 2 MnO 3 .(1- a )LiM 6 O 2-α X α   Formula 7
wherein, in Formula 7, 0<a<1 and 0≤a<2, M 6 comprises
Ni and
Co, Mn, Zr, Al, Re, V, Cr, Fe, B, Ru, Ti, Nb, Mo, Mg, Pt, or a combination thereof, and
X is F, Cl, Br, S, or P.

19 . The composite cathode active material of claim 1 , wherein the secondary particle comprising the lithium nickel transition metal oxide having a layered crystal structure has a mean particle diameter of about 10 micrometers to about 20 micrometers.

20 . The composite cathode active material of claim 1 , wherein the lithium nickel transition metal oxide having a layered crystal structure is a compound represented by Formula 8 or 9:
Li x Ni 1-y-z Mn z Co y O 2   Formula 8
wherein, in Formula 8, 0.8≤x≤1.1, 0≤y≤0.2, 0≤z≤0.2, and 0.8≤1-y-z≤0.99,
Li x Ni 1-y-z Al z Co y O 2   Formula 9

wherein, in Formula 9, 0.8≤x≤1.1, 0≤y≤0.2, 0≤z≤0.2, and 0.8≤1-y-z≤0.99.

21 . The composite cathode active material of claim 1 , wherein a total amount of the metal oxide in the coating is in a range of about 0.01 parts by weight to about 20 parts by weight, with respect to 10

Assignees

• Samsung Electronics Co Ltd
• Samsung Sdi Co Ltd

Inventors

• Hong Sukgi
• Shin Dongwook
• Yu Byongyong
• Park Jinhwan
• Song Jayhyok
• Yeon Donghee
• Choi Byungjin
• Ha Jinsu
• Ham Dongjin

Classifications

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/505

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

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/366 Primary

  as layered products · CPC title