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-11799066-B2
Application number	US-201917041233-A
Country	US
Kind code	B2
Filing date	Apr 1, 2019
Priority date	Apr 6, 2018
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

A positive electrode active material includes a lithium transition metal oxide, which is doped with doping element M 2 , wherein M 2 is at least one selected from the group consisting of Al, Ti, Mg, Zr, W, Y, Sr, Co, F, Si, Na, Cu, Fe, Ca, S, and B, and contains nickel in an amount of 60 mol % or more based on a total number of moles of transition metals excluding lithium, wherein the lithium transition metal oxide has a single particle form, and includes a center portion having a layered structure and a surface portion having a rock-salt structure, and the doping element M 2 is included in an amount of 3,580 ppm to 7,620 ppm based on a total weight of the positive electrode active material.

First claim

The invention claimed is:

1. A positive electrode active material comprising:
a lithium transition metal oxide doped with doping element M 2 ,
wherein M 2 is at least one selected from the group consisting of aluminum (Al), titanium (Ti), magnesium (Mg), zirconium (Zr), tungsten (W), yttrium (Y), strontium (Sr), cobalt (Co), fluorine (F), silicon (Si), sodium (Na), copper (Cu), iron (Fe), calcium (Ca), sulfur (S), and boron (B), and
wherein the lithium transition metal oxide contains nickel in an amount of 60 mol % or more based on a total number of moles of transition metals excluding lithium,
wherein the lithium transition metal oxide has a single particle form and comprises a center portion having a layered structure and a surface portion having a rock-salt structure, and
the doping element M 2 is included in an amount of 3,580 ppm to 7,620 ppm based on a total weight of the positive electrode active material.

2. The positive electrode active material of claim 1 , wherein a grain size of the positive electrode active material is in a range of 180 nm to 300 nm.

3. The positive electrode active material of claim 1 , wherein the doping element M 2 comprises Sr.

4. The positive electrode active material of claim 1 , wherein the surface portion is a region located within 100 nm from a surface toward a center of a particle.

5. The positive electrode active material of claim 1 , wherein the lithium transition metal oxide is represented by Formula 1:
Li 1+a [Ni x Co y M 1 z M 2 w ] 1−a O 2   [Formula 1]

wherein, in Formula 1,
0≤a≤0.2, 0.6≤x<1, 0<y≤0.4, 0<z≤0.4, 0<w≤0.1, and x+y+z+w=1,
M 1 comprises at least one selected from the group consisting of manganese (Mn) and Al, and
M 2 comprises at least one selected from the group consisting of Al, Ti, Mg, Zr, W, Y, Sr, Co, F, Si, Na, Cu, Fe, Ca, S, and B.

6. The positive electrode active material of claim 1 , further comprising a coating element M 3 -containing coating layer formed on a surface of the lithium transition metal oxide, wherein M 3 comprises at least one selected from the group consisting of Al, Ti, Mg, Zr, W, Y, Sr, Co, F, Si, Na, Cu, Fe, Ca, S, and B.

7. The positive electrode active material of claim 6 , wherein a total amount of the doping element M 2 and the coating element M 3 is in a range of 4,580 ppm to 9,120 ppm based on the total weight of the positive electrode active material.

8. The positive electrode active material of claim 1 , wherein the positive electrode active material has an average particle diameter of 3.5 μm to 7 μm.

9. A method of preparing a positive electrode active material, comprising:
mixing a transition metal precursor containing nickel in an amount of 60 mol % or more based on a total number of moles of transition metals, a lithium raw material, and a doping element M 2 -containing raw material, wherein M 2 is at least one selected from the group consisting of aluminum (Al), titanium (Ti), magnesium (Mg), zirconium (Zr), tungsten (W), yttrium (Y), strontium (Sr), cobalt (Co), fluorine (F), silicon (Si), sodium (Na), copper (Cu), iron (Fe), calcium (Ca), sulfur (S), and boron (B)), and
sintering the mixture at 800° C. to 1,000° C. to prepare a lithium transition metal oxide having a single particle form,
wherein the doping element M 2 -containing raw material is mixed such that an amount of the doping element M 2 is in a range of 3,580 ppm to 7,620 ppm based on a total weight of the positive electrode active material.

10. The method of claim 9 , further comprising:
forming a coating layer on a surface of the positive electrode active material by mixing the positive electrode active material and a coating element M 3 -containing raw material, wherein M 3 comprises at least one selected from the group consisting of Al, Ti, Mg, Zr, W, Y, Sr, Co, F, Si, Na, Cu, Fe, Ca, S, and B, and
performing a heat treatment.

11. The method of claim 10 , wherein the heat treatment is performed at 350° C. to 800° C.

12. The method of claim 10 , wherein the doping element M 2 -containing raw material and the coating element M 3 -containing raw material are mixed such that a total amount of the doping element M 2 and the coating element M 3 is in a range of 4,580 ppm to 9,120 ppm based on the total weight of the positive electrode active material.

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

14. A lithium secondary battery comprising the positive electrode of claim 13 .

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Yoo Tae Gu
• Park Young Uk
• Hwang Jin Tae
• Jung Wang Mo
• Park Sung Bin

Classifications

• H01M4/131 Primary

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

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/1391

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

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title