Lithium Secondary Battery

Patent metadata

Field	Value
Publication number	US-2018175388-A1
Application number	US-201715841708-A
Country	US
Kind code	A1
Filing date	Dec 14, 2017
Priority date	Dec 16, 2016
Publication date	Jun 21, 2018
Grant date	—

Abstract

A lithium secondary battery includes a cathode formed from a cathode active material including a first cathode active material particle and a second cathode active material particle, an anode and a separator interposed between the cathode and the anode. The first cathode active material particle includes a lithium metal oxide including a continuous concentration gradient in at least one region between a central portion and a surface portion. The second cathode active material particle includes a lithium metal oxide including elements the same as those of the first cathode active material particle, and the second cathode active material particle has a uniform composition from a central portion to a surface.

First claim

What is claimed is:

1 . A lithium secondary battery, comprising:
a cathode formed from a cathode active material including a first cathode active material particle and a second cathode active material particle; an anode; and a separator interposed between the cathode and the anode, wherein the first cathode active material particle includes a lithium metal oxide including a continuous concentration gradient in at least one region between a central portion and a surface portion, and wherein the second cathode active material particle includes a lithium metal oxide including elements the same as those of the first cathode active material particle, and the second cathode active material particle has a uniform composition from a central portion to a surface.

2 . The lithium secondary battery according to claim 1 , wherein the first cathode active material particle includes a first metal having a continuously decreasing concentration between the central portion and the surface portion, and a second metal having a continuously increasing concentration between the central portion and the surface portion.

3 . The lithium secondary battery according to claim 2 , wherein the first cathode active material particle further includes a third metal having a constant concentration from the central portion to the surface portion.

4 . The lithium secondary battery according to claim 3 , wherein the first cathode active material particle is represented by the following Chemical Formula 1:
Li x M1 a M2 b M3 c O y wherein, in the Chemical Formula 1 above, M 1 , M 2 and M 3 each represents the first metal, the second metal and the third metal, and are selected from Ni, Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga or B, and 0<x≤1.1, 2≤y≤2.02, 0<a<1, 0<b<1, 0<c<1, and 0<a+b+c≤1.

5 . The lithium secondary battery according to claim 4 , wherein 0.6≤a≤0.95 and 0.05≤b+c≤0.4 in the Chemical Formula 1.

6 . The lithium secondary battery according to claim 4 , wherein 0.7≤a≤0.9 and 0.1<b+c≤0.3 in the Chemical Formula 1.

7 . The lithium secondary battery according to claim 4 , wherein the first metal is nickel (Ni), the second metal is manganese (Mn), and the third metal is cobalt (Co).

8 . The lithium secondary battery according to claim 1 , wherein the first cathode active material particle includes a concentration gradient layer formed between the central portion and the surface portion.

9 . The lithium secondary battery according to claim 8 , wherein the concentration gradient layer includes a continuous concentration gradient, and
wherein the central portion and the surface portion each has a constant concentration composition, and the central portion and the surface portion have different concentration compositions from each other through the concentration gradient layer.

10 . The lithium secondary battery according to claim 1 , wherein the first cathode active material particle has the continuous concentration gradient throughout an entire region from the central portion to a surface thereof.

11 . The lithium secondary battery according to claim 1 , wherein each of the first cathode active material particle and the second cathode active material particle includes nickel (Ni), manganese (Mn) and cobalt (Co), and
wherein a concentration or a molar ratio of Ni is greater than that of each Mn and Co in the first cathode active material particle and the second cathode active material particle.

12 . The lithium secondary battery according to claim 11 , wherein a concentration or a molar ratio of Mn and a concentration or a molar ratio of Co are the same in the first cathode active material particle and the second cathode active material particle.

13 . The lithium secondary battery according to claim 11 , wherein the concentration or the molar ratio of Ni is greater than a sum of concentrations or molar ratios of Mn and Co in the first cathode active material particle and the second cathode active material particle.

14 . The lithium secondary battery according to claim 1 , wherein the second cathode active material particle is represented by the following Chemical Formula 2:
Li x M1′ a M2′ b M3′ c O y
wherein, in the Chemical Formula 2 above, M1′, M2′ and M3′ are selected from Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, W or B, and 0<x≤1.1, 2≤y≤2.02, 0.58≤a≤0.62, 0.18b≤0.22 and 0.18≤c≤0.22.

15 . The lithium secondary battery according to claim 14 , wherein 0.59≤a≤0.61, 0.19≤b≤0.21 and 0.19≤c≤0.21 in the Chemical Formula 2.

16 . The lithium secondary battery according to claim 11 , wherein M 1 ′, M 2 ′ and M 3 ′ are nickel (Ni), manganese (Mn) and cobalt (Co), respectively.

17 . The lithium secondary battery according to claim 1 , wherein a blending weight ratio of the first cathode active material particle and the second cathode active material particle is in a range from 6:4 to 1:9.

18 . The lithium secondary battery according to claim 1 , wherein a blending weight ratio of the first cathode active material particle and the second cathode active material particle is in a range from 4:6 to 1:9.

19 . The lithium secondary battery according to claim 1 , an average diameter (D 50 ) of the second cathode active material particle is in a range from 3 μm to 15 μm.

20 . The lithium secondary battery according to claim 1 , an average diameter (D 50 ) of the second cathode active material particle is in a range from 7 μm to 15 μm.

Assignees

• Sk Innovation Co Ltd

Inventors

• Han Kook Hyun
• Yoo Kyung Bin
• Hwang Duck Chul

Classifications

• H01M4/131

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/525 Primary

  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