Positive Electrode Active Material For Secondary Battery And Method Of Preparing The Same

Patent metadata

Field	Value
Publication number	US-2019165362-A1
Application number	US-201816320859-A
Country	US
Kind code	A1
Filing date	Feb 2, 2018
Priority date	Feb 2, 2017
Publication date	May 30, 2019
Grant date	—

Abstract

The present invention relates to a positive electrode active material for a secondary battery, which includes a core including a lithium composite metal oxide, and a surface treatment layer which is disposed on the core and includes an amorphous oxide containing a lithium (Li) oxide, a boron (B) oxide, and an aluminum (Al) oxide, wherein an amount of a lithium by-product present on a surface of the positive electrode active material is less than 0.55 wt % based on a total weight of the positive electrode active material, and a method of preparing the same.

First claim

1 . A positive electrode active material for a secondary battery, the positive electrode active material comprising:
a core including a lithium composite metal oxide; and a surface treatment layer which is disposed on the core and includes an amorphous oxide containing a lithium oxide, a boron oxide, and an aluminum oxide, wherein the lithium oxide, the boron oxide, and the aluminum oxide are chemically bonded to one another, and in the amorphous oxide in the surface treatment layer, an amount of the aluminum oxide is greater than an amount of the boron oxide, and an amount of a lithium by-product present on a surface of the positive electrode active material is less than 0.55 wt % based on a total weight of the positive electrode active material.

2 . The positive electrode active material for a secondary battery of claim 1 , wherein the lithium composite metal oxide is represented by Formula 1:
Li a (Ni x Co y M1 z ) b M2 c O 2   <Formula 1>
wherein, in Formula 1, M1 is at least one element selected from the group consisting of manganese and aluminum, and M2 is at least one element selected from the group consisting of barium, calcium, zirconium, titanium, magnesium, tantalum, niobium, and molybdenum, wherein 1≤a≤1.5, 0.9≤b≤1, 0≤c≤0.1, 0.6≤x<1, 0<y<0.4, 0<z≤0.4, and b+c=1.

3 . The positive electrode active material for a secondary battery of claim 1 , wherein a mole ratio of the boron oxide to the aluminum oxide is in a range of greater than 1:1 to less than 1:2.5.

4 . The positive electrode active material for a secondary battery of claim 1 , wherein the lithium oxide is Li 2 O, the boron oxide is B 2 O 3 , and the aluminum oxide is Al 2 O 3 .

5 . The positive electrode active material for a secondary battery of claim 4 , wherein the Li 2 O, the B 2 O 3 , and the Al 2 O 3 are chemically bonded to one another in a form selected from the group consisting of 2LiAl 7 B 4 O 5 , 2LiAlB 2 O 5 , and 2Li 2 AlB 2 O 5 .

6 . The positive electrode active material for a secondary battery of claim 1 , wherein the surface treatment layer has an average thickness of 20 nm to 100 nm.

7 . The positive electrode active material for a secondary battery of claim 1 , wherein the positive electrode active material has an average particle diameter (D 50 ) of 1 μm to 20 μm.

8 . The positive electrode active material for a secondary battery of claim 1 , wherein the lithium composite metal oxide is a secondary particle formed by agglomeration of primary particles, and
further comprises a segregation phase of Zr oxide on a surface of the secondary particle or at an interface between the primary particles.

9 . A method of preparing a positive electrode active material for a secondary battery, the method comprising:
preparing a mixture by mixing a lithium composite metal oxide, a boron-containing raw material, and an aluminum-containing raw material; and forming a surface treatment layer including an amorphous oxide on a core including the lithium composite metal oxide by performing a heat treatment on the mixture in an oxygen atmosphere, wherein the forming of the amorphous oxide is to form an amorphous oxide containing lithium, boron, and aluminum by reaction of a lithium by-product present on a surface of the lithium composite metal oxide with the boron-containing raw material and the aluminum-containing raw material, an amount of the aluminum-containing raw material included is greater than 1 time to less than 2.5 times an amount of the boron-containing raw material included, and the heat treatment is performed in a temperature range of 500° C. to 800° C.

10 . The method of claim 9 , wherein the boron-containing raw material is mixed in an amount of 0.1 parts by weight to 0.8 parts by weight and the aluminum-containing raw material is mixed in an amount of 0.1 parts by weight to 1 parts by weight, based on 100 parts by weight of the lithium composite metal oxide.

11 . The method of claim 9 , wherein the boron-containing raw material comprises at least one of H 3 BO 3 , HBPO 4 , B 2 O 3 , B 2 O 5 , Li 2 B 4 O 7 , or (NH 4 ) 2 B 4 O 7 .

12 . The method of claim 9 , wherein the aluminum-containing raw material comprises at least one of Al(OH) 3 , Al 2 (SO 4 ) 3 , AlCl 3 , or Al(NO 3 ) 3 .

13 . The method of claim 9 , wherein the lithium by-product comprises at least one of LiOH or Li 2 CO 3 .

14 . A positive electrode for a secondary battery, the positive electrode comprising the positive electrode active material of claim 1 , a binder, a conductive agent, and a positive electrode collector.

15 . A secondary battery comprising: the positive electrode of claim 14 , a negative electrode disposed to face the positive electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte.

Assignees

• Lg Chemical Ltd

Inventors

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

Classifications

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/131 Primary

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

• H01M10/052

  Li-accumulators · CPC title

• 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