Positive active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-10566612-B2
Application number	US-201515521933-A
Country	US
Kind code	B2
Filing date	Jun 15, 2015
Priority date	Oct 27, 2014
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A positive active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same are disclosed, and the positive active material for a rechargeable lithium battery includes: a layered lithium composite oxide core; a first coating layer on the surface of the core and magnesium doped at a lithium site in the core; a NiO-phase second coating layer on the first coating layer wherein the NiO-phase has a rock salt structure; and a third coating layer on the second coating layer and including lithium magnesium phosphate.

First claim

What is claimed is:

1. A positive active material for a rechargeable lithium battery, comprising:
a layered lithium composite oxide core;
a first coating layer on the surface of the core, the first coating layer comprising the layered lithium composite oxide comprised in the core being doped with magnesium at a lithium site;
a NiO-phase second coating layer on the first coating layer wherein the NiO-phase has a rock salt structure; and
a third coating layer on the second coating layer, the third coating layer comprising lithium magnesium phosphate.

2. The positive active material of claim 1 , wherein the core is represented by Chemical Formula 1:
Li a Ni b CO c Mn d M e O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, M is a metal of Al, Zr, B or a combination thereof, 0.98≤a≤1.2, 0.1≤b≤0.9, 0.1≤c≤1, 0.1≤d≤0.9, 0≤e≤0.05, and b+c+d+e=1.

3. The positive active material of claim 1 , wherein the first coating layer is represented by Chemical Formula 2:
Li a-x Mg x Ni b Co c Nn d M e O 2   [Chemical Formula 2]

wherein, in Chemical Formula 2, M is a metal of Al, Zr, B or a combination thereof, 0.98≤a≤1.2, 0.1≤b≤0.9, 0.1≤c≤0.9, 0≤e≤0.05, b+c+d+e=1, and 0.01≤x≤0.1.

4. The positive active material of claim 1 , wherein the third coating layer is represented by Chemical Formula 3:
Li a MgPO 4   [Chemical Formula 3]

wherein, in Chemical Formula 1, 0.1≤a≤0.9.

5. The positive active material of claim 1 , wherein the total amount of the first, second, and third coating layers is greater than 0 wt % and less than or equal to 3 wt % based on 100 wt % of the total positive active material.

6. The positive active material of claim 1 , wherein a thickness of the third coating layer is greater than 0 nm and less than or equal to 10 nm.

7. The positive active material of claim 1 , wherein a thickness of the second coating layer is greater than 0 nm and less than or equal to 10 nm.

8. The positive active material of claim 1 , wherein in the first coating layer, a doping amount of magnesium in a lithium site is less than or equal to 1.9 mol %.

9. The positive active material of claim 1 , wherein the total thickness of the first, second, and third coating layers may be greater than 0 nm and less than or equal to 500 nm.

10. The positive active material of claim 1 , wherein the positive active material has a primary particle shape, and the primary particle has a diameter of less than or equal to 500 nm.

11. The positive active material of claim 10 , wherein the primary particles are aggregated to form a secondary particle, and the secondary particle has a diameter of 1 to 10 μm.

12. The positive active material of claim 11 , which further comprises a fourth coating layer comprising the lithium magnesium phosphate on the surface of the secondary particle.

13. A rechargeable lithium battery comprising:
a positive electrode including the positive active material for rechargeable lithium battery of claim 1 ;
a negative electrode including a negative active material; and

an electrolyte.

Assignees

• Ulsan Nat Inst Science & Tech Unist

Inventors

• Cho Jaephil

Classifications

• H01M4/505

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/1391

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