Lithium-sulfur battery

Patent metadata

Field	Value
Publication number	US-11545720-B2
Application number	US-201816624750-A
Country	US
Kind code	B2
Filing date	May 4, 2018
Priority date	Jun 20, 2017
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

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

The invention claimed is:

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 and a conductive polymer,
wherein the conductive polymer is one or more selected from the group consisting of polyaniline, polyazulene, polypyridine, polyindole, polycarbazole, polyazine, polyquinone, polyacetylene, polyselenophene, polytellurophene, poly-para-phenylene, polyethylenedioxythiophene, polyethylene glycol and combinations thereof, and
wherein a weight ratio of the radical compound having the nitroxyl radical functional group to the conductive polymer is in a range of 3:1 to 7:1.

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 having the nitroxyl radical functional group 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 having the nitroxyl radical functional group 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 and a conductive polymer,
wherein the conductive polymer is one or more selected from the group consisting of polyaniline, polyazulene, polypyridine, polyindole, polycarbazole, polyazine, polyquinone, polyacetylene, polyselenophene, polytellurophene, poly-para-phenylene, polyethylenedioxythiophene, polyethylene glycol and combinations thereof, and
wherein a weight ratio of the tetramethylpiperidine N-oxyl to the conductive polymer is in a range of 3:1 to 7:1.

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. 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
• Lg Energy Solution Ltd

Inventors

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

Classifications

• H01M50/46

  Separators, membranes or diaphragms characterised by their combination with electrodes · 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

• H01M10/4235

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M50/449

  having a layered structure · CPC title