Positive electrode active material for lithium secondary battery and method for preparing the same

Patent metadata

Field	Value
Publication number	US-9825294-B2
Application number	US-201113821615-A
Country	US
Kind code	B2
Filing date	Sep 8, 2011
Priority date	Sep 8, 2010
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

Provided is a method for preparing a positive electrode active material for a lithium secondary battery, the method comprising: mixing and reacting a nickel source, a cobalt source, and an aluminum source, ammonia water, sucrose, and a pH adjusting agent to prepare a mixed solution; drying and oxidizing the mixed solution to prepare a positive electrode active material precursor; and adding a lithium source to the positive electrode active material precursor and firing them to prepare a positive electrode active material for a lithium secondary battery.

First claim

The invention claimed is:

1. A method for preparing a porous positive electrode active material for a lithium secondary battery, the method comprising:
mixing and reacting raw materials including a metal aqueous solution containing a nickel source, a cobalt source, and an aluminum source, ammonia water, sucrose as a pore forming agent, and a pH adjusting agent to prepare a positive electrode active material precursor wherein the sucrose is present in the positive electrode active material precursor;
drying and naturally oxidizing the positive electrode active material precursor to prepare a solid positive electrode active material precursor;
mixing a lithium salt in a solid form with the solid positive electrode active material precursor to prepare a solid mixture; and
firing the solid mixture in air to prepare a positive electrode active material for a lithium secondary battery represented by the following Chemical Formula 1
Li 1+z Ni 1−x−y Co x Al y O 2   [Chemical Formula 1]

(z, x, y, and 1−x−y are real numbers that satisfy the following Equations, respectively: 0≦z≦0.3, 0.05≦x≦0.3, and 0.4≦1−x−y<0.95),
wherein a content of the sucrose contained in the metal aqueous solution is 5 to 30 weight %,
wherein in firing, the sucrose which is present in the solid positive electrode active material precursor is carbonized and pores are formed in the positive electrode active material, and
wherein the positive electrode active material has a total pore volume of 6.5×10 −2 to 8.0×10 −2 cc/g and a specific surface area of 0.7 to 1.0 m 2 /g.

2. The method of claim 1 , wherein the firing is performed for 15 to 20 hours through a first step of raising a temperature to 400˜500° C. at a rate of 0.5 to 1° C./min; and a second step of raising a temperature to 800˜900° C. at a rate of 1 to 2° C./min.

3. The method of claim 1 , wherein a concentration of the metal in the metal aqueous solution is 1 to 3M.

4. The method of claim 3 , wherein a molar ratio of nickel, cobalt, and aluminum contained in the metal aqueous solution is 0.5 to 0.94:0.05 to 0.3: 0.01 to 0.3.

5. The method of claim 3 , wherein the metal aqueous solution is supplied into a reactor at a rate of 0.2 to 0.5 L/hr.

6. The method of claim 1 , wherein pH of the mixture at the time of conducting the mixing reaction is 11 to 13.

7. The method of claim 1 , wherein a concentration of the ammonia water is 0.1 to 0.25 times a mole concentration of the metal in the metal aqueous solution.

8. The method of claim 7 , wherein the ammonia water is supplied at a rate of 0.02 to 0.05 L/hr.

9. The method of claim 1 , wherein the lithium salt is LiOH.

Assignees

• Oh Sung Woo
• Sun Hee Young
• Do Yu Rim
• Lee Hyung Bok
• Sk Innovation Co Ltd

Inventors

• Oh Sung Woo
• Sun Hee Young
• Do Yu Rim
• Lee Hyung Bok

Classifications

• H01M4/26

  Processes of manufacture · CPC title

• C01D15/02

  Oxides; Hydroxides · CPC title

• C01P2006/11

  Powder tap density · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/52

  of nickel, cobalt or iron · CPC title