Composite positive active material, method of preparing the same, and lithium secondary battery including positive electrode including the same

Patent metadata

Field	Value
Publication number	US-11133501-B2
Application number	US-201615337541-A
Country	US
Kind code	B2
Filing date	Oct 28, 2016
Priority date	Oct 30, 2015
Publication date	Sep 28, 2021
Grant date	Sep 28, 2021

Abstract

A composite positive active material includes a lithium nickel cobalt aluminum composite oxide. A full width at half maximum (FWHM) of a peak of a (104) plane of the lithium nickel cobalt aluminum composite oxide is 0.15 or less and an FWHM of a peak of a (108) plane of the lithium nickel cobalt aluminum composite oxide is 0.15 or less, the peaks being obtained by X-ray diffraction analysis using a CuKα X-ray. A method of preparing the composite positive active material, and a lithium secondary battery including a positive electrode including the composite positive active material are disclosed.

First claim

What is claimed is:

1. A composite positive active material comprising a lithium nickel cobalt aluminum composite oxide that consists of lithium, nickel, cobalt, aluminum, and oxygen, wherein:
a full width at half maximum (FWHM) of a peak of a (104) plane of the lithium nickel cobalt aluminum composite oxide is 0.15 or less,
an FWHM of a peak of a (108) plane of the lithium nickel cobalt aluminum composite oxide is 0.15 or less, the peaks being obtained by X-ray diffraction analysis using a CuKα X-ray, and
the composite positive active material has an average crystal size of 800 nm or less.

2. The composite positive active material as claimed in claim 1 , wherein an amount of aluminum in the composite positive active material is in a range of about 5 mol % to about 10 mol % with respect to a total amount of nickel, cobalt, and aluminum.

3. The composite positive active material as claimed in claim 1 , wherein a cation mixing ratio in the composite positive active material is 5.0% or less based on a total amount of lithium sites.

4. The composite positive active material as claimed in claim 1 , wherein the composite positive active material is a compound represented by Formula 1 below:
LiNi a Co b Al c O 2 ,  [Formula 1]

wherein in formula 1, 0.7≤a<1.0, 0<b≤0.3, and 0.05≤c≤0.1.

5. The composite positive active material as claimed in claim 1 , wherein the composite positive active material is LiNi 0.8 Co 0.1 Al 0.1 O 2 ,LiNi 0.7 Co 0.2 Al 0.1 O 2 , LiNi 0.7 Co 0.25 Al 0.05 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , or LiNi 0.9 Co 0.05 Al 0.5 O 2 .

6. A method of preparing the composite positive active material as claimed in claim 1 , the method comprising:
performing a first heat treatment on nickel cobalt oxide represented by Formula 2 below and aluminum oxide under an oxidative gas atmosphere to obtain nickel cobalt aluminum oxide represented by Formula 3 below; and
performing a second heat treatment on the nickel cobalt aluminum oxide and a lithium precursor under an oxidative gas atmosphere to obtain the composite positive active material,
Ni x Co 1-x O  [Formula 2]

wherein in formula 2, 0.7≤x<1.0,
Ni x Co 1-x-y Al y O 2   [Formula 3]

wherein in formula 3, 0.7≤x<1.0 and 0.05≤y≤0.1.

7. The method as claimed in claim 6 , wherein the first heat treatment is performed under an oxidative gas atmosphere at a temperature between about 400° C. and about 1,200° C.

8. The method as claimed in claim 6 , wherein the second heat treatment is performed under an oxidative gas atmosphere at a temperature between about 400° C. and about 1,200° C.

9. A lithium secondary battery comprising a positive electrode including a composite positive active material including a lithium nickel cobalt aluminum composite oxide that consists of lithium, nickel, cobalt, aluminum, and oxygen, wherein the composite positive active material has:
a full width at half maximum (FWHM) of a peak of a (104) plane of 0.15 or less,
an FWHM of a peak of a (108) plane of 0.15 or less, the peaks being obtained by X-ray diffraction analysis using a CuKα X-ray, and
an average crystal size of 800 nm or less.

10. The lithium secondary battery as claimed in claim 9 , wherein an amount of aluminum in the composite positive active material is in a range of about 5 mol % to about 10 mol % with respect to a total amount of nickel, cobalt, and aluminum.

11. The lithium secondary battery as claimed in claim 9 , wherein a cation mixing ratio in the composite positive active material is 5.0% based on a total amount of lithium sites.

12. The lithium secondary battery as claimed in claim 9 , wherein the composite positive active material is a compound represented by Formula 1 below:
LiNi a Co b Al c O 2 ,  [Formula 1]

wherein 0.7≤a<1.0, 0<b≤0.3, and 0.05≤c≤0.1.

13. The lithium secondary battery as claimed in claim 9 , wherein the composite positive active material is LiNi 0.8 Co 0.1 Al 0.1 O 2 , LiNi 0.7 Co 0.2 Al 0.1 O 2 , LiNi 0.7 Co 0.25 Al 0.05 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , or LiNi 0.9 Co 0.05 Al 0.5 O 2 .

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Sanghoon
• Cho Kwanghwan
• Lee Eunsung
• Park Dohyung
• Kim Ilseok
• Choi Sol

Classifications

• C01G53/82

  Compounds containing nickel, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M50/107

  having curved cross-section, e.g. round or elliptic (H01M50/103, H01M50/109, H01M50/11 take precedence) · CPC title

• C01G53/50

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

• C01P2002/70

  defined by measured X-ray, neutron or electron diffraction data · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title