Lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2019221829-A1
Application number	US-201916247732-A
Country	US
Kind code	A1
Filing date	Jan 15, 2019
Priority date	Jan 15, 2018
Publication date	Jul 18, 2019
Grant date	—

Abstract

A lithium secondary battery comprises a cathode, an anode, a separator and a nonaqueous electrolyte solution. The cathode includes a first cathode active material in which at least one of metals included in the first cathode material has a concentration gradient region between a central portion and a surface portion, and a second cathode active material having a single particle structure. The lithium secondary battery has improved life-span and penetration stability.

First claim

What is claimed is:

1 . A lithium secondary battery, comprising:
a cathode including a first cathode active material and a second cathode active material; an anode; and a separator interposed between the cathode and the anode, wherein the first cathode active material includes a lithium metal oxide including a concentration gradient region between a central portion and a surface, wherein the second cathode active material includes a lithium metal oxide having a single particle structure.

2 . The lithium secondary battery according to claim 1 , wherein the single particle structure includes a single crystalline structure.

3 . The lithium secondary battery according to claim 1 , wherein the first cathode active material includes a first lithium metal oxide represented by Chemical Formula 1:
Li x M1 a M2 b M3 c O y   [Chemical Formula 1]
wherein in Chemical Formula 1, at least one of M1, M2 and M3 has a concentration gradient region between a central portion of the first metal oxide and a surface portion of the first metal oxide, and M1, M2 and M3 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,
0<x1.1, 2≤y≤2.02, 0≤a≤1, 0≤b≤1, 0≤c≤1, and 0<a+b+c≤1

4 . The lithium secondary battery according to claim 3 , wherein M1 is Ni, 0.6≤a≤0.95 and 0.05≤b+c≤0.4 in Chemical Formula 1.

5 . The lithium secondary battery according to claim 3 , wherein M1 is Ni, 0.7≤a≤0.9 and 0.1≤b+c≤0.3 in Chemical Formula 1.

6 . The lithium secondary battery according to claim 1 , wherein the second cathode material includes a second lithium metal oxide represented by Chemical Formula 2:
Li x Ni a Co b Mn c M4 d M5 e O y   [Chemical Formula 2]
wherein, in Chemical Formula 2, M4 includes at least one selected from Ti, Zr, Al, Mg or Cr, M5 includes least one selected from Sr, Y, W or Mo, 0<x<1.5, 2≤y≤2.02, 0.313≤a≤0.353, 0.313≤b≤0.353, 0.313≤c≤0.353, 0≤d≤0.03, 0≤e≤0.03 and 0.98≤a+b+c≤1.02.

7 . The lithium secondary battery according to claim 6 , wherein the second lithium metal oxide includes Li 1.0 Ni 1/3 Co 1/3 Mn 1/3 O 2 .

8 . The lithium secondary battery according to claim 1 , wherein the second cathode active material has a primary particle shape.

9 . The lithium secondary battery according to claim 1 , wherein the second cathode active material shows an exothermic peak of 25 J/g or less at 320° C. or more in a DSC measurement.

10 . The lithium secondary battery according to claim 1 , wherein a blending weight ratio of the first cathode active material and the second cathode active material is in a range from 80:20 to 10:90.

11 . The lithium secondary battery according to claim 1 , wherein a blending weight ratio the first cathode active material and the second cathode active a material is in a range from 50:50 to 10:90.

Assignees

• Sk Innovation Co Ltd

Inventors

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

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/54

  of silver · CPC title

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M4/505

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

• 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