Cathode active material for lithium secondary battery, method of manufacturing the same and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2022077458-A1
Application number	US-202117464882-A
Country	US
Kind code	A1
Filing date	Sep 2, 2021
Priority date	Sep 7, 2020
Publication date	Mar 10, 2022
Grant date	—

Abstract

A cathode active material for a lithium secondary battery according to embodiments of the present invention includes a lithium composite oxide containing sodium, and a coating formed on the surface of the lithium composite oxide. The coating contains sodium and aluminum. Sodium is distributed to a depth of 35 nm or more from a surface of the cathode active material. Thus, electrical and thermal properties of a lithium secondary battery are improved.

First claim

What is claimed is:

1 . A cathode active material for a lithium secondary battery, comprising:
a lithium composite oxide containing sodium; and a coating formed on the surface of the lithium composite oxide, the coating containing sodium and aluminum, wherein sodium is distributed to a depth of 35 nm or more from a surface of the cathode active material.

2 . The cathode active material for a lithium secondary battery according to claim 1 , wherein an amount of sodium contained in the coating is greater than an amount of sodium contained in the lithium composite oxide.

3 . The cathode active material for a lithium secondary battery according to claim 1 , wherein sodium is distributed to a depth of 35 nm to 200 nm from the surface of the cathode active material.

4 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the coating further contains boron.

5 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the coating comprises an aluminum-containing compound including at least one of an aluminum-containing oxide, an aluminum-containing hydroxide or a lithium-aluminum compound.

6 . The cathode active material for a lithium secondary battery according to claim 5 , wherein the aluminum-containing compound comprises at least one selected from the group consisting of AlO, Al 2 O, Al 2 O 3 , LiAlO 2 , LiAlB 4 , LiAlB 2 O 5 , Al(OH) 3 , LiAlH 4 and LiAlOH.

7 . The cathode active material for a lithium secondary battery according to claim 5 , wherein the coating further comprises a boron-containing oxide.

8 . The cathode active material for a lithium secondary battery according to claim 7 , wherein the boron-containing oxide includes LiBO 2 , LiB 3 O 5 or Li 2 B 4 O 7 .

9 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the coating at least partially covers the surface of the lithium composite oxide.

10 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the coating is discontinuously formed on the surface of the lithium composite oxide.

11 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium composite oxide includes nickel, and a mole fraction of nickel in the lithium composite oxide is 0.6 or more among elements other than lithium and oxygen.

12 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium composite oxide has an average particle diameter (D 50 ) from 3 μm to 25 μm.

13 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the cathode active material includes aluminum, and aluminum is distributed to a depth of 37 nm or more from the surface of the cathode active material.

14 . The cathode active material for a lithium secondary battery according to claim 13 , wherein aluminum is distributed to a depth of 37 nm to 200 nm from the surface of the cathode active material.

15 . A method of manufacturing a cathode active material for a lithium secondary battery, comprising:
preparing an aqueous reaction solution containing a sodium-aluminum compound; and wet-coating a lithium composite oxide using the aqueous reaction solution.

16 . The method of claim 15 , wherein the sodium-aluminum compound includes sodium-aluminum oxide or sodium-aluminum hydroxide.

17 . The method of claim 15 , wherein the wet-coating comprises:
forming a preliminary cathode active material by immersing a surface of the lithium composite oxide in the aqueous reaction solution; and thermally treating the preliminary cathode active material.

18 . The method of claim 17 , wherein forming the preliminary cathode active material comprises adding a boron-containing compound to the aqueous reaction solution.

19 . The method of claim 18 , wherein the boron-containing compound includes boric acid.

20 . The method of claim 17 , wherein thermally treating the preliminary cathode active material is performed at a temperature from 250° C. to 700° C.

21 . A lithium secondary battery, comprising:
a cathode comprising the cathode active material for a lithium secondary battery according to claim 1 ; and an anode facing the cathode.

Assignees

• Sk Innovation Co Ltd

Inventors

• Park Sung Soon
• Kim Jik Soo
• Choi Ji Hoon

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/362 Primary

  Composites · CPC title

• H01M10/0525

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

• C01G53/50

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• H01M4/366 Primary

  as layered products · CPC title