Positive electrode 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 material

Patent metadata

Field	Value
Publication number	US-11637275-B2
Application number	US-201816633455-A
Country	US
Kind code	B2
Filing date	Sep 19, 2018
Priority date	Sep 19, 2017
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

The present disclosure relates to a positive electrode material which includes a first positive electrode active material and a second positive electrode active material, wherein the second positive electrode active material has an electrical conductivity of 0.1 μS/cm to 150 μS/cm, which is measured after the second positive electrode active material is prepared in the form of a pellet by compressing the second positive electrode active material at a rolling load of 400 kgf to 2,000 kgf, a method of preparing the positive electrode material, and a positive electrode for a lithium secondary battery and a lithium secondary battery which include the positive electrode material.

First claim

The invention claimed is:

1. A positive electrode material comprising:
a first positive electrode active material represented by Formula 1; and
a second positive electrode active material represented by Formula 2,
wherein the second positive electrode active material has an electrical conductivity of 0.1 μS/cm to 150 μS/cm, which is measured after the second positive electrode active material is prepared in a form of a pellet by compressing the second positive electrode active material at a rolling load of 400 kgf to 2,000 kgf,
wherein the first positive electrode active material and the second positive electrode active material are included in a weight ratio of 40:60 to 90:10,
wherein the second positive electrode active material has a grain size of 200 nm to 500 nm, and
wherein the operation starting voltage of the second positive electrode active material is 3.75 V or more:
LiCo 1-a M 1 a O 2   [Formula 1]

LiNi b Co c Mn d M 2 e O 2   [Formula 2]

wherein, in Formula 1, M 1 comprises at least one selected from the group consisting of aluminum (Al), titanium (Ti), magnesium (Mg), and zirconium (Zr), and 0<a≤0.2, and
wherein, in Formula 2, M 2 comprises at least one selected from the group consisting of Al, Ti, Mg, Zr, yttrium (Y), strontium (Sr), and boron (B), and 0<b≤0.6, 0<c≤0.35, 0<d≤0.35, and 0<e≤0.1.

2. The positive electrode material of claim 1 , wherein the first positive electrode active material has an average particle diameter (D 50 ) of 10 μm or more.

3. The positive electrode material of claim 1 , wherein the second positive electrode active material has an average particle diameter (D 50 ) of 8 μm or less.

4. The positive electrode material of claim 1 , wherein the second positive electrode active material comprises the doping element M 2 in an amount of 2,000 ppm to 10,000 ppm based on a total weight of the second positive electrode active material.

5. A method of preparing a positive electrode material, the method comprising:
preparing a first positive electrode active material represented by Formula 1 by mixing and sintering a cobalt oxide, a lithium-containing raw material, and a doping element M 1 -containing raw material;
preparing a second positive electrode active material represented by Formula 2 by solid-phase mixing and sintering a nickel oxide, a cobalt oxide, a manganese oxide, a doping element M 2 -containing raw material, and a lithium-containing raw material; and
mixing the first positive electrode active material and the second positive electrode active material,
wherein the second positive electrode active material has an electrical conductivity of 0.1 μS/cm to 150 μS/cm, which is measured after the second positive electrode active material is prepared in a form of a pellet by compressing the second positive electrode active material at a rolling load of 400 kgf to 2,000 kgf, and
wherein the operation starting voltage of the second positive electrode active material is 3.75 V or more:
LiCo 1-a M 1 a O 2   [Formula 1]

LiNi b Co c Mn d M 2 e O 2   [Formula 2]

wherein, in Formula 1, M 1 comprises at least one selected from the group consisting of aluminum (Al), titanium (Ti), magnesium (Mg), and zirconium (Zr), and 0≤a≤0.2, and
wherein, in Formula 2, M 2 comprises at least one selected from the group consisting of Al, Ti, Mg, Zr, yttrium (Y), strontium (Sr), and boron (B), and 0<b≤0.6, 0<c≤0.35, 0<d≤0.35, and 0<e≤0.1.

6. The method of claim 5 , wherein, in the preparing of the second positive electrode active material, the solid-phase mixing is performed such that a molar ratio of nickel:cobalt:manganese:lithium:doping element M 2 is in a range of 40:30:30:104:2 to 60:20:20:100:0.

7. The method of claim 5 , wherein the first positive electrode active material and the second positive electrode active material are mixed in a weight ratio of 40:60 to 90:10.

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

9. A lithium secondary battery comprising the positive electrode of claim 8 .

10. The positive electrode material of claim 1 , wherein the first positive electrode active material and the second positive electrode active material are included in a weight ratio of 50:50 to 80:20.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

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

Classifications

• H01M4/364 Primary

  as mixtures · CPC title

• H01M4/505

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

• H01M4/663

  containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres · CPC title

• H01M4/0435

  Rolling or calendering · CPC title

• H01M4/525

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