Lithium secondary battery and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-2019393479-A1
Application number	US-201916447522-A
Country	US
Kind code	A1
Filing date	Jun 20, 2019
Priority date	Jun 20, 2018
Publication date	Dec 26, 2019
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 separation layer interposed between the cathode and the anode. The first cathode active material particle includes a lithium metal oxide including a concentration gradient and has a secondary particle structure formed from an assembly of primary particles. The second cathode active material particle includes a lithium metal oxide having a single particle structure. The first and second cathode active material particles each includes at least two metals except from lithium, and an amount of nickel is the largest among those of the metals in each of the first and second cathode active material particles.

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 separation layer interposed between the cathode and the anode, wherein the first cathode active material particle includes a lithium metal oxide including a concentration gradient and has a secondary particle structure formed from an assembly of primary particles, wherein the second cathode active material particle includes a lithium metal oxide having a single particle structure, wherein the first and second cathode active material particles each includes at least two metals except from lithium, and an amount of nickel is the largest among those of the metals in each of the first and second cathode active material particles.

2 . The lithium secondary battery according to claim 1 , wherein the first cathode active material particle includes a concentration gradient region between a core region and a shell region.

3 . The lithium secondary battery according to claim 1 , wherein the first cathode active material particle has a continuous concentration gradient from a central portion to a surface.

4 . The lithium secondary battery according to claim 1 , wherein the first cathode active material particle includes a lithium metal oxide represented by the following Chemical Formula 1:
Li x M1 a M2 b M3 c O y   [Chemical Formula 1]
wherein, in the Chemical Formula 1 above, M1 is Ni, and 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 and B, and 0<x≤1.1, 2≤y≤2.02, 0.6≤a≤0.95, and 0.05≤b+c≤0.4.

5 . 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.

6 . The lithium secondary battery according to claim 4 , wherein M2 is manganese (Mn) and M3 is cobalt (Co).

7 . The lithium secondary battery according to claim 1 , wherein the second cathode active material particle includes a lithium metal oxide represented by the following Chemical Formula 2:
Li x Ni a Co b Mn c M4 d M5 c O y   [Chemical Formula 2]
wherein, in the Chemical Formula 1 above, M4 includes at least one element selected from Ti, Zr, Al, Mg, Si, B or Cr, and M5 includes at least one element selected from Sr, Y, W or Mo, wherein, in the Chemical Formula 2, 0≤x≤1.5, 2≤y≤2.02, 0.48≤a≤0.52, 0.18≤b≤0.22, 0.28≤c≤0.32, 0≤d≤0.25, 0≤e≤0.15 and 0.98≤a+b+c≤1.02.

8 . The lithium secondary battery according to claim 7 , wherein 0.49≤a≤0.51, 0.19≤b≤0.21 and 0.29≤c≤0.31 in the Chemical Formula 2.

9 . The lithium secondary battery according to claim 1 , wherein a mixing weight ratio of the first cathode active material particle and the second cathode active material particle is in a range from 5:5 to 1:9.

10 . The lithium secondary battery according to claim 1 , wherein the second cathode active material particle has a single crystalline structure.

11 . The lithium secondary battery according to claim 1 , wherein the second cathode active material particle has a constant concentration from a central portion to a surface.

12 . The lithium secondary battery according to claim 1 , wherein an average diameter of the second cathode active material particle is smaller than that of the first cathode active material particle.

13 . The lithium secondary battery according to claim 12 , wherein the number of the second cathode active material particles in a unit volume of the cathode is greater than that of the first cathode active material particles.

14 . The lithium secondary battery according to claim 12 , wherein the second cathode active material particles serve as pore fillers between the first cathode active material particles.

15 . The lithium secondary battery according to claim 1 , wherein an amount of Ni in the second cathode active material particle is smaller than that in the first cathode active material particle.

16 . The lithium secondary battery according to claim 1 , wherein each of the first and second cathode active material particles further includes cobalt (Co) and manganese (Mn),
wherein an amount of Co and an amount of Mn in the second cathode active material particle are each greater than that in the first cathode active material particle.

Assignees

• Sk Innovation Co Ltd

Inventors

• Kim Soo Ho
• Kang Min Gu
• Do Young Hoon
• Cho Yong Hyun

Classifications

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M10/058

  Construction or manufacture · 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

• H01M10/052

  Li-accumulators · CPC title

• H01M4/505

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