Positive Electrode Active Material For Secondary Battery, Manfuacturing Method Thereof, And Secondary Battery Including Same

Patent metadata

Field	Value
Publication number	US-2019300382-A1
Application number	US-201716316554-A
Country	US
Kind code	A1
Filing date	Dec 19, 2017
Priority date	Dec 28, 2016
Publication date	Oct 3, 2019
Grant date	—

Abstract

The present invention provides a positive electrode active material for a secondary battery, which includes a lithium transition metal oxide including nickel (Ni) and cobalt (Co), and at least one selected from the group consisting of aluminum (Al), manganese (Mn), and a combination thereof. The lithium transition metal oxide is characterized in that the content of nickel (Ni) in the total transition metal elements is 80 mol % or more, and the cation mixing ratio of Ni cations in a lithium layer in the lithium transition metal oxide structure is 1.1% or less.

First claim

1 . A method for preparing a positive electrode active material for a secondary battery, comprising:
preparing a lithium transition metal oxide including nickel (Ni) and cobalt (Co), and at least one selected from the group consisting of aluminum (Al), manganese (Mn), and a combination thereof; rinsing the lithium transition metal oxide with water to remove lithium impurities present on a surface of the lithium transition metal oxide; and subjecting the lithium transition metal oxide rinsed with water to a high-temperature heat treatment to form a high-temperature heat treated lithium transition metal oxide, wherein the high-temperature heat treatment includes: elevating a temperature to the elevated temperature; maintaining the elevated temperature; and cooling, wherein an amount of time spent in the elevating the temperature step is 20 to 30% of a total time of the high-temperature heat treatment.

2 . The method of claim 1 , wherein an amount of time spent in the maintaining step is 40 to 50% of the total time of the high-temperature heat treatment.

3 . The method of claim 1 , wherein an amount of time spent in the cooling step is 20 to 30% of the total time of the high-temperature heat treatment.

4 . The method of claim 1 , wherein the total time of the high-temperature heat treatment is 6 to 10 hours.

5 . The method of claim 1 , wherein, in the maintaining the elevated temperature step, the elevated temperature step is 600° C. to 900° C.

6 . The method of claim 1 , wherein, in the elevating the temperature step, the temperature is elevated at a rate of step 2 to 7° C./min.

7 . The method of claim 1 , wherein the cooling step is natural cooling.

8 . The method of claim 1 , wherein the high-temperature heat treatment is performed in an oxygen atmosphere having an oxygen partial pressure of 80% or more.

9 . The method of claim 1 , wherein the rinsing is performed using 50 to 100 parts by weight of pure water based on 100 parts by weight of the lithium transition metal oxide.

10 . The method of claim 1 , wherein the rinsing is performed at a temperature of −10 to 30° C.

11 . The method of claim 1 , wherein the lithium transition metal oxide is represented by Formula 1 below:
Li a Ni 1-x1-y1-z1 Co x1 M 1 y1 M 2 z1 M 3 q1 O 2   [Formula 1]
(in Formula 1, M 1 is at least one selected from the group consisting of Mn, Al, and a combination thereof, and M 2 and M 3 are each independently at least one selected from the group consisting of Ba, Ca, Zr, Ti, Mg, Ta, Nb, W, Mo, and a combination thereof, and 1.0≤a≤1.5, 0<x1≤0.2, 0<y1≤0.2, 0≤z1≤0.1, 0≤q1≤0.1, and 0<x1+y1+z1≤0.2).

12 . The method of claim 1 , wherein the preparing a lithium transition metal oxide is performed by mixing a precursor represented by Formula 2 below and a lithium-containing raw material, and firing the mixture at 700 to 900° C.:
Ni 1-x2-y2-z2 Co x2 M 1 y2 M 2 z2 (OH) 2   [Formula 2]

(in Formula 2, M 1 is at least one selected from the group consisting of Mn, Al, and a combination thereof, M 2 is at least one selected from the group consisting of Ba, Ca, Zr, Ti, Mg, Ta, Nb, W, Mo, and a combination thereof, and 0<x2≤0.2, 0<y2≤0.2, 0≤z2≤0.1, 0≤q2≤0.1, 0<x2+y2+z2≤0.2).

13 . The method of claim 1 , wherein the method further comprises:
mixing the high-temperature heat-treated lithium transition metal oxide with at least one selected from the group consisting of H 3 BO 3 , B 2 O 3 , Al 2 O 3 , and a combination thereof to form a mixture, and heat treating the mixture at a temperature of 200 to 500° C. to form a coating layer on the surface of the lithium transition metal oxide.

14 . A positive electrode active material for a secondary battery, comprising:
a lithium transition metal oxide including nickel (Ni) and cobalt (Co), and at least one selected from the group consisting of aluminum (Al), manganese (Mn), and a combination thereof, wherein the lithium transition metal oxide is characterized in that the content of nickel (Ni) in the total transition metal elements is 80 mol % or more, and the cation mixing ratio of Ni cations in a lithium layer in the lithium transition metal oxide structure is 1.1% or less.

15 . The positive electrode active material of claim 14 , wherein the content of lithium by-products present in the positive active material is greater than 0.3 wt % to 1 wt % or less.

16 . The positive electrode active material of claim 14 , wherein the lithium transition metal oxide comprises a layered structural phase and a spinel-like structural phase.

17 . The positive electrode active material of claim 14 , wherein the positive active material has a crystal density of 4.76 g/cm 3 or more.

18 . The positive electrode active material of claim 14 , wherein the positive active material has a BET specific surface area of 0.5 m 2 /g or less.

19 . A positive electrode for a secondary battery comprising the positive electrode active material for a secondary battery of claim 14 .

20 . A lithium secondary battery comprising the positive electrode for a secondary battery of claim 19 .

Assignees

• Lg Chemical Ltd

Inventors

• Kim Ji Hye
• Park Byung Chun
• Baek So Ra
• Yoo Tae Gu
• Jung Wang Mo

Classifications

• C01P2002/60

  Compounds characterised by their crystallite size · CPC title

• H01M4/131

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

• C01G53/42

  containing alkali metals, e.g. LiNiO2 · CPC title

• H01M4/505

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

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title