Positive electrode active material for lithium secondary battery, method of preparing the same, and positive electrode for lithium secondary battery and lithium secondary battery which include the positive electrode active material

Patent metadata

Field	Value
Publication number	US-11489156-B2
Application number	US-201816754027-A
Country	US
Kind code	B2
Filing date	Oct 19, 2018
Priority date	Oct 20, 2017
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

A positive electrode active material includes a lithium transition metal oxide represented by Formula 1, and a lithium-containing inorganic compound layer formed on a surface of the lithium transition metal oxide,Li1+a(NibCocXdM1eM2f)1−aO2  [Formula 1]in Formula 1, X is at least one selected from the group consisting of manganese (Mn) and aluminum (Al), M1 is at least one selected from the group consisting of sulfur (S), fluorine (F), phosphorus (P), and nitrogen (N), M2 is at least one selected from the group consisting of zirconium (Zr), boron (B), cobalt (Co), tungsten (W), magnesium (Mg), cerium (Ce), tantalum (Ta), titanium (Ti), strontium (Sr), barium (Ba), hafnium (Hf), F, P, S, lanthanum (La), and yttrium (Y), 0≤a≤0.1, 0.6≤b≤0.99, 0≤c≤0.2, 0≤d≤0.2, 0<e≤0.1, and 0<f≤0.1. A method of preparing the positive electrode active material, a positive electrode and a lithium secondary battery are also provided.

First claim

The invention claimed is:

1. A positive electrode active material comprising:
a lithium transition metal oxide represented by Formula 1; and
a lithium-containing inorganic compound layer formed on a surface of the lithium transition metal oxide:
Li 1+a (Ni b Co c X d M 1 e M 2 f ) 1−a O 2   [Formula 1]

wherein, in Formula 1,
X is at least one selected from the group consisting of manganese (Mn) and aluminum (Al),
M 1 is sulfur (S),
M 2 is zirconium (Zr), and
0≤a≤0.1, 0.6≤b≤0.99, 0≤c≤0.2, 0≤d≤0.2, 0<e≤0.1, and 0<f≤0.1.

2. The positive electrode active material of claim 1 , wherein the lithium-containing inorganic compound layer comprises at least one selected from the group consisting of Li 3 BO 3 , LiBO 2 , Li 3 PO 4 , and LiPO 3 .

3. The positive electrode active material of claim 1 , wherein the lithium-containing inorganic compound layer has a thickness of 1 nm to 200 nm.

4. The positive electrode active material of claim 1 , wherein an amount of lithium impurities in a surface of the positive electrode active material is in a range of 0.1 wt % to 1.0 wt % based on a total weight of the positive electrode active material.

5. A method of preparing a positive electrode active material, the method comprising:
mixing and sintering a doping element M 1 -doped transition metal hydroxide precursor, a lithium raw material, and a doping element M 2 -containing raw material to prepare a lithium transition metal oxide represented by Formula 1;
mixing the lithium transition metal oxide with an aqueous inorganic acid solution to prepare a mixed solution; and
drying and heat-treating the mixed solution to form a lithium-containing inorganic compound layer on a surface of the lithium transition metal oxide:
Li 1+a (Ni b Co c X d M 1 e M 2 f ) 1−a O 2   [Formula 1]

wherein, in Formula 1,
X is at least one selected from the group consisting of manganese (Mn) and aluminum (Al),
M 1 is at least one selected from the group consisting of sulfur (S), fluorine (F), phosphorus (P), and nitrogen (N),
M 2 is at least one selected from the group consisting of zirconium (Zr), boron (B), cobalt (Co), tungsten (W), magnesium (Mg), cerium (Ce), tantalum (Ta), titanium (Ti), strontium (Sr), barium (Ba), hafnium (Hf), F, P, S, lanthanum (La), and yttrium (Y), and
0≤a≤0.1, 0.6≤b≤0.99, 0≤c≤0.2, 0≤d≤0.2, 0<e≤0.1, and 0<f≤0.1.

6. The method of claim 5 , wherein the doping element M 1 -doped transition metal hydroxide precursor, the lithium raw material, and the doping element M 2 -containing raw material are mixed in a molar ratio of 1:1.00:0.02 to 1:1.30:0.1.

7. The method of claim 5 , wherein lithium impurities present in the surface of the lithium transition metal oxide react with the inorganic acid to form a lithium-containing inorganic compound layer.

8. The method of claim 5 , wherein the aqueous inorganic acid solution has a pH of 2 to 10.

9. The method of claim 5 , wherein the aqueous inorganic acid solution comprises at least one selected from the group consisting of boric acid and phosphoric acid.

10. The method of claim 5 , wherein the heat-treating of the mixed solution is performed at 200° C. to 400° C.

11. A positive electrode for a lithium secondary battery, the positive electrode comprising the positive electrode active material of claim 1 .

12. A lithium secondary battery comprising the positive electrode of claim 11 .

Assignees

• Lg Chemical Ltd

Inventors

• Ju Seo Hee

Classifications

• C01P2006/80

  Compositional purity · 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

• C01P2004/80

  Particles consisting of a mixture of two or more inorganic phases · CPC title

• H01M4/5825

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

• C01G53/50 Primary

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