Positive Electrode Active Material for Lithium Secondary Battery and Method of Preparing the Same

Patent metadata

Field	Value
Publication number	US-2023034497-A1
Application number	US-202117788814-A
Country	US
Kind code	A1
Filing date	Jan 29, 2021
Priority date	Jan 30, 2020
Publication date	Feb 2, 2023
Grant date	—

Abstract

A positive electrode active material, method of making the same, and positive electrode and lithium secondary battery include the same are disclosed herein. In some embodiments, a positive electrode active material in a form of single particles, includes a lithium transition metal oxide having nickel (Ni) in an amount greater than 50 mol % based on a total number of moles of transition metals excluding lithium, wherein a single particle has a region of 50 nm or less from a surface of the single particle along a center direction, and wherein a structure belonging to space group FD3-M and a structure belonging to space group Fm3m are formed in the region, and wherein a generation rate of fine powder having an average particle diameter (D50) of 1 μm or less is in a range of 5% to 30% when the positive electrode active material is rolled at 650 kgf/cm2.

First claim

1 . A positive electrode active material comprising:
a lithium transition metal oxide having nickel (Ni) in an amount of greater than 50 mol % based on a total number of moles of transition metals in the lithium transition metal oxide, wherein the transition metals excluding exclude lithium, wherein the positive electrode active material is in a form of single particles, wherein a single particle has a region of 50 nm or less from a surface of the single particle along a center direction, and wherein a structure belonging to space group FD3-M and a structure belonging to space group Fm3m are formed in the, and wherein a generation rate of fine powder having an average particle diameter (D 50 ) of 1 μm or less is in a range of 5% to 30% when the positive electrode active material is rolled at 650 kgf/cm 2 .

2 . The positive electrode active material of claim 1 , wherein the positive electrode active material has a formation ratio of 0.2 to 0.7, where the formation ratio is the length of the structure belonging to space group FD3-M in the region to the length of the structure belonging to space group Fm3m in the region, where each length is measured along the center direction.

3 . The positive electrode active material of claim 1 , wherein the structure belonging to space group FD3-M is a spinel structure.

4 . The positive electrode active material of claim 1 , wherein the structure belonging to space group Fm3m is a rock-salt structure.

5 . The positive electrode active material of claim 1 , wherein the single particles have an average particle diameter (D 50 ) of 1 μm to 10 μm.

6 . 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 Mn z M1 w O 2   [Formula 1]
wherein, in Formula 1, M1 is at least one selected from the group consisting of aluminum (Al), magnesium (Mg), vanadium (V), titanium (Ti), and zirconium (Zr), and 0≤a≤0.20, 0.5<x<1.0, 0<y<0.5, 0<z<0.5, 0<w<0.05, and x+y+z+w=1.

7 . The positive electrode active material of claim 1 , wherein the generation rate is in a range of 8% to 25%.

8 . A method of preparing a positive electrode active material, the method comprising:
mixing a transition metal hydroxide and a lithium (Li) raw material such that a molar ratio of Li in the Li raw material to transition metals in the transition metal hydroxide is in a range of 1 to 1.2, wherein the transition metal hydroxide has nickel (Ni) in an amount of greater than 50 mol % based on a total number of moles of transition metals; and over-sintering the mixture at 800° C. to 890° C. for 10 hours to 20 hours to prepare a positive electrode active material in the form of single particles, wherein a single particle has a region of 50 nm or less from a surface of the single particle along a center direction, and wherein a structure belonging to space group FD3-M and a structure belonging to space group Fm3m are formed in the region, and wherein the positive electrode active material has a generation rate of fine powder having an average particle diameter (D 50 ) of 1 μm or less is-in a range of 5% to 30% when the positive electrode active material is rolled at 650 kgf/cm 2 .

9 . The method of claim 8 , wherein the mixing is performed such that the molar ratio is in a range of 1.05 to 1.15.

10 . The method of claim 8 , wherein the over-sintering is performed in an oxygen or air atmosphere.

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 Energy Solution Ltd

Inventors

• Park Sang Min
• Lho Eun Sol
• Park Sung Bin
• Kim Seul Ki
• Wang Wen Xiu
• Do Joong Yeop
• Jung Wang Mo

Classifications

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/505

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

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/0471

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