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

Patent metadata

Field	Value
Publication number	US-2018145322-A1
Application number	US-201715713950-A
Country	US
Kind code	A1
Filing date	Sep 25, 2017
Priority date	Nov 18, 2016
Publication date	May 24, 2018
Grant date	—

Abstract

A composite cathode active material includes a first cathode active material including a core including a first lithium transition metal oxide represented by Formula 1 and having a first layered crystalline phase that belongs to a R-3m space group; and a coating layer disposed on the core and including a second lithium transition metal oxide having a plurality of layered crystalline phases, wherein each layered crystalline phase of the plurality of layered crystalline phases has a different composition:
Li a MO 2   Formula 1
wherein, in Formula 1, 1.0≤a≤1.03; and M includes nickel and an element including a Group 4 element to a Group 13 element other than nickel.

First claim

What is claimed is:

1 . A composite cathode active material comprising a first cathode active material comprising:
a core comprising a first lithium transition metal oxide represented by Formula 1 and having a first layered crystalline phase that belongs to a R-3m space group; and a coating layer disposed on the core and comprising a second lithium transition metal oxide having a plurality of layered crystalline phases, in which each layered crystalline phase of the plurality of layered crystalline phases has a different composition
Li a MO 2   Formula 1

wherein, in Formula 1, 1.0≤a≤1.03; and M comprises nickel and an element comprising a Group 4 to a Group 13 element other than nickel.

2 . The composite cathode active material of claim 1 , wherein, in the first lithium transition metal oxide, an amount of nickel is greater than an amount of the Group 4 element to the Group 13 element other than nickel.

3 . The composite cathode active material of claim 1 , wherein the first lithium transition metal oxide is represented by Formula 2:
Li a Ni b M2 c M3 d O 2   Formula 2
wherein, in Formula 2, 1.0≤a≤1.03, 0.4<b<1.0, 0<c<0.3, 0<d<0.4, and b+c+d=1; and M2 and M3 are different from each other and comprise manganese, vanadium, chromium, iron, cobalt, zirconium, rhenium, aluminum, boron, germanium, ruthenium, tin, titanium, niobium, molybdenum, platinum, or a combination thereof.

4 . The composite cathode active material of claim 1 , wherein the first lithium transition metal oxide is represented by Formula 3:
Li a Ni b Co c Mn d O 2   Formula 3
wherein, in Formula 3, 1.0≤a≤1.03, 0.4<b<1.0, 0<c<0.3, and 0<d<1.0.4.

5 . The composite cathode active material of claim 1 , wherein the plurality of layered crystalline phases comprises
a second layered crystalline phase that belongs to a C2/m space group; and a third layered crystalline phase that belongs to a R-3m space group.

6 . The composite cathode active material of claim 7 , wherein the second layered crystalline phase has a composition represented by Formula 4:
Li 2 MnO 3 .  Formula 4

7 . The composite cathode active material of claim 7 , the third layered crystalline phase has a composition represented by Formula 5:
LiMO 2   Formula 5
wherein, in Formula 5, M comprises at least two elements comprising nickel, manganese, vanadium, chromium, iron, cobalt, zirconium, rhenium, aluminum, boron, germanium, ruthenium, tin, titanium, niobium, molybdenum, platinum, or a combination thereof.

8 . The composite cathode active material of claim 1 , wherein the second lithium transition metal oxide is represented by Formula 6:
a Li 2 MnO 3 ·(1− a )LiMO 2   Formula 6
wherein, in Formula 6, 0.2<a<1; and M comprises at least two elements comprising nickel, manganese, vanadium, chromium, iron, cobalt, zirconium, rhenium, aluminum, boron, germanium, ruthenium, tin, titanium, niobium, molybdenum, platinum, or a combination thereof.

9 . The composite cathode active material of claim 1 , wherein the second lithium transition metal oxide is represented by Formula 7:
Li x M4 y M5 z Mn w O 2   Formula 7
wherein, in Formula 7, 1.07≤x≤1.20, 0.1≤y<0.8, 0≤z≤0.13, 0.46≤w<0.8, and 0.80≤y+z+w≤0.93; and M4 and M5 each independently comprise nickel, vanadium, chromium, iron, cobalt, zirconium, rhenium, aluminum, boron, germanium, ruthenium, tin, titanium, niobium, molybdenum, platinum, or a combination thereof.

10 . The composite cathode active material of claim 1 , wherein the coating layer comprising the second lithium transition metal oxide is a discontinuous coating on a surface of the core.

11 . The composite cathode active material of claim 1 , wherein an amount of residual lithium in the composite cathode active material is less than 1500 parts per million, based on a total content of the composite cathode active material.

12 . The composite cathode active material of claim 1 , wherein an average particle diameter of the first cathode active material is in a range of about 10 micrometers to about 20 micrometers.

14 . The composite cathode active material of claim 1 further comprising a second cathode active material having an average particle diameter of about 5 micrometers or less.

14 . The composite cathode active material of claim 14 , wherein the second cathode active material comprises the second lithium transition metal oxide having an average particle diameter in a range of about 1 micrometer to about 5 micrometers.

15 . The composite cathode active material of claim 13 , wherein an amount of the second cathode active material is in a range of about 1 weight percent to about 30 weight percent, based on a total weight of the composite cathode active material.

16 . The composite cathode active material of claim 1 , wherein the composite active material has a press density of about 3 grams per cubic centimeter or greater after pressing at a pressure of 2.6 tons/cm 2 for 30 seconds.

17 . A cathode comprising a composite cathode active material of claim 1 .

18 . A lithium battery comprising the cathode of claim 16 .

19 . The lithium battery of claim 17 , wherein during a charging process, the lithium battery is charged to a voltage of about 4.5 volts or greater with respect to a lithium metal.

20 . A method of preparing a composite cathode active material, the method comprising:
providing a first lithium transition metal oxide represented by Formula 1 and having a first layered crystalline phase that belongs to a R-3m space group; combining the first lithium transition metal oxide, a precursor of a second lithium transition metal oxide, and a lithium source to prepare a mixture; and heat-treating the mixture in an oxidation atmosphere to obtain a composite cathode active material
Li a MO 2   Formula 1

wherein, in Formula 1, 1.0≤a≤1.03; and M comprises nickel and an element comprising a Group 4 to a Group 13 element other than nickel.

Assignees

• Samsung Electronics Co Ltd
• Samsung Sdi Co Ltd

Inventors

• Choi Byungjin
• Yu Byongyong
• Park Jinhwan
• Song Jayhyok

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/525 Primary

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

• H01M4/366 Primary

  as layered products · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/131

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