Lithium-sulfur battery

Patent metadata

Field	Value
Publication number	US-2021143510-A1
Application number	US-201816624750-A
Country	US
Kind code	A1
Filing date	May 4, 2018
Priority date	Jun 20, 2017
Publication date	May 13, 2021
Grant date	—

Abstract

A lithium-sulfur battery comprising a separator in which an adsorption layer including a radical compound having a nitroxyl radical site is formed, and in particular, to a lithium-sulfur battery suppressing elution of lithium polysulfide by using an adsorption layer including a radical compound having a nitroxyl radical site and optionally a conductive material on at least one surface of a separator. In the lithium-sulfur battery, elution and diffusion may be prevented by a radical compound having a nitroxyl radical site, a stable radical compound, adsorbing lithium polysulfide eluted from positive electrode, and in addition thereto, electrical conductivity is further provided to provide a reaction site of a positive electrode active material, and as a result, battery capacity and lifetime properties are enhanced.

First claim

1 . A lithium-sulfur battery comprising:
a positive electrode comprising a sulfur-carbon composite; a negative electrode disposed opposite to the positive electrode; and a separator provided between the positive electrode and the negative electrode, wherein the separator comprises a separator body; and a lithium polysulfide adsorption layer formed on at least one surface of the separator body, and the adsorption layer comprises a radical compound having a nitroxyl radical functional group.

2 . The lithium-sulfur battery of claim 1 , wherein the radical compound is a polymer having the nitroxyl radical functional group in a molecule thereof.

3 . The lithium-sulfur battery of claim 2 , wherein the polymer is polymerized from a monomer comprising any one functional group selected from the group consisting of (meth)acrylate, acrylonitrile, an anhydride, styrene, epoxy, isocyanate and a vinyl group.

4 . The lithium-sulfur battery of claim 2 , wherein the polymer is one or more selected from the group consisting of poly(2,2,6,6-tetramethyl-1-piperidinyloxyl-4-yl-(meth)acrylate, poly(2,2,6,6-tetramethyl-1-piperidinyloxyl-4-yl vinyl-ether, poly(TEMPO-substituted norbornene), poly(2,2,5,5-tetramethylpyrrolidine-1-oxyl-3-yl ethylene oxide, poly[2,3-bis(2,2,6,6-tetramethylpiperidine-1-oxyl-4-oxycarbonyl)-5-norbonene], poly(tetramethylpiperidinoxy)acrylamide and combinations thereof.

5 . A lithium-sulfur battery comprising:
a positive electrode comprising a sulfur-carbon composite; a negative electrode disposed opposite to the positive electrode; and a separator provided between the positive electrode and the negative electrode, wherein a portion of the separator comprises tetramethylpiperidine N-oxyl.

6 . The lithium-sulfur battery of claim 2 , wherein the polymer is poly(2,2,6,6-tetramethyl-1-piperidinyloxyl-4-yl methacrylate.

7 . The lithium-sulfur battery of claim 1 , wherein a content of the radical compound having the nitroxyl radical functional group is 80% by weight or greater based upon a total weight of the adsorption layer.

8 . The lithium-sulfur battery of claim 1 , wherein the adsorption layer has a thickness of 0.1 μm to 10 μm.

9 . The lithium-sulfur battery of claim 1 , wherein the adsorption layer further comprises a conductive polymer.

10 . The lithium-sulfur battery of claim 9 , wherein the conductive polymer is one or more selected from the group consisting of polyaniline, polypyrrole, polythiophene, polyazulene, polypyridine, polyindole, polycarbazole, polyazine, polyquinone, polyacetylene, polyselenophene, polytellurophene, poly-para-phenylene, polyphenylene vinylene, polyphenylene sulfide, polyethylenedioxythiophene, polyethylene glycol and combinations thereof.

11 . A method for manufacturing the lithium-sulfur battery of claim 1 , comprising preparing the separator by a method comprising:
i) preparing a separator body; ii) preparing a solution by mixing a radical compound having a nitroxyl radical site to a solvent; iii) coating the solution on at least one surface of the separator body; and iv) forming a lithium polysulfide adsorption layer by drying the coated separator.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Kihyun
• Kim Soohyun
• Yang Doo Kyung
• Jin Sun Mi
• Lee Changhoon

Classifications

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M50/449

  having a layered structure · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M2300/0085

  Immobilising or gelification of electrolyte · CPC title