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-2017288262-A1
Application number	US-201715630014-A
Country	US
Kind code	A1
Filing date	Jun 22, 2017
Priority date	Dec 31, 2014
Publication date	Oct 5, 2017
Grant date	—

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

1 . A method for manufacturing a lithium secondary battery positive active material having a concentration gradient layer, the method comprising:
inputting a chelating agent solution into a reactor; continuously inputting a core forming solution, a chelating agent solution, and an 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, a chelating agent solution, and an alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a barrier layer; preparing a shell forming solution and continuously mixedly inputting a chelating agent solution, an 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; drying the precipitate; and thermally treating the dried precipitate.

2 . The method of claim 1 , wherein the barrier layer forming solution includes Ni and Mn.

3 . The method of claim 1 , wherein the barrier layer forming solution includes Ni and Mn in a mole ratio of 30:70 to 70:30.

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

5 . 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).

6 . 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).

7 . The method of claim 1 , wherein the preparing of the shell forming solution and the continuously mixedly inputting of the chelating agent solution, the alkaline solution, the core forming solution, and the shell forming solution into the reactor at the same time comprises:
mixing the core forming solution and the shell forming solution in an additional preliminary reactor and continuously inputting the mixed solution into the reactor at the same time.

8 . The method of claim 1 , further comprising:
continuously mixedly putting a shell forming solution, a chelating agent solution, and an alkaline solution into the reactor at the same time and obtaining a spherical precipitate forming a shell layer between the preparing of the shell forming solution and the continuously mixedly putting of the chelating agent solution, the alkaline solution, the core forming solution, and the shell forming solution into the reactor at the same time, and the drying of the precipitate.

9 . A lithium secondary battery positive active material precursor, having a concentration gradient layer, manufactured by the method according to claim 1 .

10 . The lithium secondary battery positive active material precursor of claim 9 , wherein a barrier layer has a thickness equal to or larger than 0.01 μm and smaller than 2.0 μm, or equal to or larger than 1% and smaller than 20% of a volume of particles.

11 . The lithium secondary battery positive active material precursor of claim 9 , wherein a size of a primary particle is reduced in 10 to 40% from a size of a primary particle of a positive active material precursor having the same composition without a barrier layer.

12 . A method for manufacturing a lithium secondary battery positive active material having a concentration gradient layer, the method comprising:
mixing a lithium secondary battery positive active material precursor having a concentration gradient layer according to claim 9 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.

13 . A lithium secondary battery positive active material, having a concentration gradient layer, manufactured by the method according to claim 12 .

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

• H01M4/366 Primary

  as layered products · 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

• H01M4/505

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

• H01M10/0525 Primary

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

• C01G53/44

  containing manganese · CPC title