Method for producing positive active material precursor and positive active material for lithium secondary batteries, exhibiting concentration gradient, and positive active material precursor and positive active material for lithium secondary batteries, exhibiting concentration gradient, produced by same

Patent metadata

Field	Value
Publication number	US-10749205-B2
Application number	US-201715630014-A
Country	US
Kind code	B2
Filing date	Jun 22, 2017
Priority date	Dec 31, 2014
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

Disclosed are a method for manufacturing a lithium secondary battery positive active material exhibiting a concentration gradient and a lithium secondary battery positive active material exhibiting a concentration gradient, manufactured by the method, and more particularly, a method for manufacturing a lithium secondary battery positive active material exhibiting a concentration gradient and a lithium secondary battery positive active material exhibiting a concentration gradient, manufactured by the method, the method being characterized by forming a barrier layer so as to maintain a concentration gradient layer even in case of thermal diffusion by a subsequent thermal treatment process.

First claim

The invention claimed is:

1. A method for manufacturing a lithium secondary battery positive active material having a concentration gradient layer, the method comprising:
inputting a first chelating agent solution into a reactor;
continuously inputting a core forming solution with constant concentration, a second chelating agent solution, and a first alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a core layer;
continuously inputting a barrier layer forming solution with constant concentration, a third chelating agent solution, and a second alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a barrier layer,
wherein said barrier layer forming solution includes Ni and Mn in a mole ratio of 30:70 to 70:30,
wherein the Co molar content of the barrier layer forming solution is 0;

preparing a shell forming solution and continuously mixedly inputting a fourth chelating agent solution, a third alkaline solution, the core forming solution, and the shell forming solution into the reactor at the same time and obtaining a precipitate, which forms the concentration gradient layer where concentration of nickel-manganese-cobalt varies gradually and relatively, on a surface of the barrier layer,
wherein the core forming solution and the shell forming solution have different compositions of Ni, Co, and Mn;

continuously inputting a shell forming solution with constant concentration, a fifth chelating agent solution, and a fourth alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a shell layer,
drying the precipitate; and
thermally treating the dried precipitate,
wherein the barrier layer has a thickness equal to or larger than 0.01 μm and smaller than 2.0 μm in the positive active material particles, and
wherein said first chelating agent solution, said second chelating agent solution, said third chelating agent solution, said fourth chelating agent solution and said fifth chelating solution are the same, and
wherein said first alkaline solution, said second alkaline solution, said third alkaline solution and said fourth alkaline solution are the same.

2. The method of claim 1 , wherein the barrier layer forming solution includes Ni and Mn in a mole ratio of 50:50.

3. The method of claim 1 , wherein the core forming solution includes a mole ratio of Ni:Co:Mn=a:b:1−(a+b) (0.7≤a≤1.0, 0≤b≤0.2).

4. The method of claim 1 , wherein the shell forming solution includes a mole ratio of Ni:Co:Mn=a:b:1−(a+b) (0.3≤a≤0.6, 0≤b≤0.4).

5. The method of claim 1 , further comprising:
mixing a lithium secondary battery positive active material having a concentration gradient layer according to claim 1 with a lithium compound; and
thermally treating the mixture for 10 to 25 hours in oxidation atmosphere of air or oxygen at 750 to 1000° C.

6. A lithium secondary battery positive active material, having a concentration gradient layer, manufactured by the method according to claim 5 .

Assignees

• Ecopro Bm Co Ltd

Inventors

• Choi Moon Ho
• Kim Jik Soo
• Yun Jin Kyeong
• Jeon Suk Yong
• Jung Jae Yong
• Sung Yong Chul

Classifications

• C01G53/82

  Compounds containing nickel, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• Y02E60/10

  Energy storage using batteries · 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

• H01M10/0525 Primary

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

• H01M4/505

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