Carbon-based fiber sheet and lithium-sulfur battery including same

Patent metadata

Field	Value
Publication number	US-2021098775-A1
Application number	US-202017115016-A
Country	US
Kind code	A1
Filing date	Dec 8, 2020
Priority date	Jun 2, 2016
Publication date	Apr 1, 2021
Grant date	—

Abstract

Disclosed is a carbon-based fiber sheet and a lithium-sulfur battery including the same. The carbon-based fiber sheet for the lithium-sulfur battery is doped with a high concentration of nitrogen and thus plays a role of preventing diffusion by adsorbing lithium polysulfide eluted from a positive electrode during charging and discharging, thereby suppressing a shuttle reaction and thus improving capacity and lifecycle properties of the lithium-sulfur battery.

First claim

1 . A lithium-sulfur battery comprising:
a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; a carbon-based fiber sheet interposed between the positive electrode and the separator; and an electrolyte impregnated thereinto, wherein the carbon-based fiber sheet is doped with nitrogen at a concentration of 5% to 30% by weight based on a total weight of the carbon-based fiber sheet.

2 . The lithium-sulfur battery according to claim 1 , wherein the nitrogen is doped at a doping concentration of 10% to 25% by weight in the carbon-based fiber sheet.

3 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber comprises at least one selected from the group consisting of carbon fiber, carbon nanofiber, graphite fiber and graphene fiber.

4 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber sheet comprises at least one fabric form selected from the group consisting of felt, mat, paper and cloth.

5 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber sheet has a thickness of 0.1 μm to 100 μm.

6 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber sheet comprises a carbon-based fiber having a diameter of 0.01 μm to 100 μm.

7 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber sheet has a pore size of 0.1 μm to 10 μm and a porosity of 5% to 90%.

8 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber sheet has a specific surface area of 5 m 2 /g to 500 m 2 /g and a bulk density of 0.05 g/cm 3 to 0.2 g/cm 3 .

9 . The lithium-sulfur battery according to claim 1 , wherein the carbon-based fiber sheet is prepared by a method comprising:
i) preparing a spinning solution comprising a carbon-based precursor; ii) spinning the spinning solution to prepare a sheet in a form of a fibrous web; iii) stabilizing the sheet through heat treatment in the presence of oxygen; and iv) carbonizing the sheet in an inert atmosphere, wherein the carbon-based precursor contains a nitrogen element in the molecular structure.

10 . The lithium-sulfur battery according to claim 9 , wherein the carbon-based precursor in step i) is at least one selected from the group consisting of polyacrylonitrile, polyaniline, polypyrrole, polyimide, polybenzimidazole, polypyrrolidone, polyamide, polyamideimide, polyaramid, melamine, melamine-formaldehyde and fluorine mica.

11 . The lithium-sulfur battery according to claim 9 , wherein the carbon-based precursor comprises from 5% to 20% of nitrogen atoms in the molecular structure.

12 . The lithium-sulfur battery according to claim 9 , wherein the heat treatment in step iii) is carried out at a temperature of 100° C. to 400° C.

13 . The lithium-sulfur battery according to claim 9 , wherein the heat treatment in step iii) is carried out in an oxidizing atmosphere.

14 . The lithium-sulfur battery according to claim 9 , wherein the carbonization in the step iv) is carried out at a temperature of 600° C. to 1500° C.

15 . The lithium-sulfur battery according to claim 9 , wherein the carbonization in step iv) is carried out in the inert gas atmosphere.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Yun Kyoung
• Kim Taek Gyoung
• Sohn Kwonnam
• Yang Doo Kyung
• Im Mira

Classifications

• D06M23/06

  Processes in which the treating agent is dispersed in a gas, e.g. aerosols (aerosol compositions C09K3/30) · CPC title

• D06M13/322

  with compounds containing nitrogen · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M50/491

  Porosity · CPC title