Separator for lithium secondary battery and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2018358596-A1
Application number	US-201715761724-A
Country	US
Kind code	A1
Filing date	May 30, 2017
Priority date	May 30, 2016
Publication date	Dec 13, 2018
Grant date	—

Abstract

The present invention relates to a separator for a lithium secondary battery, including a porous resin comprising one or more polar functional groups selected from the group consisting of —C—F; and —C—OOH and —C═O on a surface thereof, wherein, among the polar functional groups, a molar ratio of —C—OOH and —C═O to —C—F ranges from 0.2:0.8 to 0.8:0.2, and a method of manufacturing the same.

First claim

1 . A separator for a lithium secondary battery, the separator comprising a porous resin comprising one or more polar functional groups selected from the group consisting of —C—F; and —C—OOH and —C═O on a surface thereof,
wherein, among the polar functional groups, a molar ratio of —C—OOH and —C═O to —C—F ranges from 0.2:0.8 to 0.8:0.2.

2 . The separator of claim 1 , wherein the one or more polar functional groups included in the porous resin are included in an amount of 0.7 mol/cm 2 to 6 mol/cm 2 with respect to a surface area of the porous resin.

3 . The separator of claim 1 , wherein the one or more polar functional groups are present in a region of 0.01 μm to 1 μm from a surface of the porous resin toward a center thereof.

4 . The separator of claim 1 , wherein a total amount of the polar functional groups included in the porous resin ranges from 0.1 wt % to 2 wt % based on 100 wt % of the separator.

5 . The separator of claim 1 , wherein the porous resin is formed of any one selected from the group consisting of high-density polyethylene, linear low-density polyethylene, low-density polyethylene, ultra-high-molecular-weight polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene, or a mixture of two or more thereof.

6 . A lithium secondary battery comprising the separator according to claim 1 .

7 . The lithium secondary battery of claim 6 , wherein the lithium secondary battery comprises an insoluble lithium salt layer formed on a surface of a negative electrode.

8 . The lithium secondary battery of claim 7 , wherein an insoluble lithium salt of the insoluble lithium salt layer comprises one or more selected from the group consisting of lithium fluoride (LiF), lithium carbonate (Li 2 CO 3 ), lithium oxide (Li 2 O), lithium oxalate (Li 2 C 2 O 4 ), and lithium hydroxide (LiOH).

9 . The lithium secondary battery of claim 7 , wherein the insoluble lithium salt layer has a thickness of 0.001 μm to 0.5 μm.

10 . The lithium secondary battery of claim 6 , wherein the lithium secondary battery comprises lithium metal as a negative electrode.

11 . A method of manufacturing a separator for a lithium secondary battery, the method comprising:
preparing a gas mixture by mixing N 2 gas, O 2 gas, or a mixture thereof with F 2 gas; and bringing the gas mixture into contact with a porous resin to form a polar functional group on a surface of the porous resin.

12 . The method of claim 11 , wherein, in the preparing of the gas mixture, a pressure ratio of the F 2 gas to the N 2 gas, the O 2 gas, or the mixture thereof ranges from 8:2 to 9:1.

13 . The method of claim 11 , wherein the preparing of the gas mixture is performed by mixing a mixture of the N 2 gas and the O 2 gas, mixed in a pressure ratio of 1:9 to 9:1, with the F 2 gas.

14 . The method of claim 11 , wherein the bringing of the gas mixture comprises bringing the gas mixture into contact with the porous resin at a pressure of 1 KPa to 60 KPa.

Assignees

• Lg Chemical Ltd

Inventors

• Woo Sang Wook
• Chae Oh Byong
• Choi Hee Won
• Kim Eun Kyung

Classifications

• H01M4/382 Primary

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M50/423

  Polyamide resins · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/491

  Porosity · CPC title

• H01M2/1653 Primary

  Electricity · mapped topic