Nonaqueous electrolyte lithium secondary battery

Patent metadata

Field	Value
Publication number	US-10153518-B2
Application number	US-201515109299-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Sep 30, 2014
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

Disclosed is a lithium secondary battery including a positive electrode, a negative electrode, a separator and a nonaqueous electrolyte, wherein the positive electrode includes Li a Ni x Mn y Co z O 2 (a+x+y+z=2, 0.9≤a≤1.1, 0≤x, 0≤y, 0≤z) as a positive electrode active material, and wherein the nonaqueous electrolyte includes (i) fluorinated cyclic carbonate expressed by Chemical Formula 1 below, (ii) propionate-based ester expressed by Chemical Formula 2 below, and (iii) non-halogenated carbonate, so that a mixture weight ratio (i:ii) thereof is 20:80 to 50:50:

wherein, in Chemical Formula 1, R 1 , R 2 , R 3 and R 4 are independently any one of F, H and methyl group, and at least one thereof is F,

wherein, in Chemical Formula 2, R 5 is alkyl group having 1 to 5 carbons.

First claim

What is claimed is:

1. A lithium secondary battery, including a positive electrode, a negative electrode, a separator and a nonaqueous electrolyte,
wherein the positive electrode includes
Li a Ni x Mn y Co z O 2 (a+x+y+z=2, 0.9≤a≤1.1, 0≤x, 0≤y, 0≤z), and
LiCoO 2,
wherein a content of the Li a Ni x Mn y Co z O 2 is 50 wt % to 100 wt % in comparison to the entire weight of the positive electrode active material, and
wherein the nonaqueous electrolyte includes (i) fluorinated cyclic carbonate expressed by Chemical Formula 1 below, (ii) propionate-based ester expressed by Chemical Formula 2 below, and (iii) non-halogenated carbonate, so that a mixture weight ratio (i:ii) thereof is 20:80 to 50:5, and
a content of the non-halogenated carbonate is 10 wt % or below in comparison to the entire weight of the nonaqueous electrolyte,

wherein, in Chemical Formula 1, R 1 , R 2 , R 3 and R 4 are independently any one of F, H and methyl group, and at least one thereof is F,

wherein, in Chemical Formula 2, R 5 is alkyl group having 1 to 5 carbons.

2. The lithium secondary battery according to claim 1 ,
wherein the propionate-based ester expressed by Chemical Formula 2 is at least one of methyl propionate, ethyl propionate and propyl propionate.

3. The lithium secondary battery according to claim 1 ,
wherein the positive electrode has a loading amount of 0.01 g/cm 2 to 0.03 g/cm 2.

4. The lithium secondary battery according to claim 1 ,
wherein the non-halogenated carbonate is any one compound selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), butylene carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylmethyl carbonate (EMC), and mixtures thereof.

5. The lithium secondary battery according to claim 1 ,
wherein the lithium secondary battery has a charging voltage of 4.3 to 5.0 V.

Assignees

• Lg Chemical Ltd

Inventors

• Yu Sung-Hoon
• Yang Doo-Kyung
• Lee Min-Hyung
• Jeon Jong-Ho

Classifications

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M2300/004

  Three solvents · CPC title

• H01M10/0525

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

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M4/502

  for non-aqueous cells (H01M4/505 takes precedence) · CPC title