Regenerative polysulfide-scavenging layers enabling lithium-sulfur batteries with high energy density and prolonged cycling life and methods of making same

Patent metadata

Field	Value
Publication number	US-10985368-B2
Application number	US-201815889603-A
Country	US
Kind code	B2
Filing date	Feb 6, 2018
Priority date	Feb 9, 2017
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

The invention relates to a method for fabricating a regenerative polysulfide-scavenging layer (RSL). The method includes embedding nanowires or nanocrystals of metal oxides with a membrane of carbon nanotubes (CNTs); and forming the RSL with the embedded nanowires or nanocrystals of the metal oxides and the membrane, so as to enable lithium-sulfur batteries with high energy density and prolonged cycling life. The invention also relates to a lithium-sulfur battery that contains the RSL.

First claim

What is claimed is:

1. A method of fabricating a regenerative poly sulfide-scavenging layer (RSL) of a lithium-sulfur battery having a lithium anode, a sulfur cathode, and a polypropylene separator disposed between the lithium anode and the sulfur cathode, comprising:
synthesizing composites of metal oxide nanowires intertwined with carbon nanotubes (CNTs) using hydrothermal reaction;
dispersing the CNTs and CNTs/metal oxide composites in ethanol by sonication;
filtrating the CNTs and the CNTs/metal oxide composites after the dispersing through a polypropylene membrane; and
forming a flexible triple-layered membrane to fabricate the RSL having middle layers embedded with interpenetrating metal oxide nanowires: and
placing the flexible triple-layered membrane between the polypropylene separator and the sulfur cathode of the lithium-sulfur battery to form the RSL therein, such that during discharging of the lithium-sulfur battery, polysulfides generated from the sulfur cathode are adsorbed by or reacted with the RSL and are immobilized onto the RSL to form polysulfides-RSL complexes: and a subsequent charging process strips away the immobilized polysulfides-RSL complexes and regenerates the RSL, thereby enabling dynamic blocking of the generated polysulfides.

2. The method of claim 1 , wherein the metal oxide nanowires are made from V 2 O 5 .

3. The method of claim 2 , further comprising:
entangling the CNTs from the dispersing to form CNTs networks for effective electron conduction, thereby allowing performing effecting redox reaction with CNTs/V 2 O 5 RSL.

4. The method of claim 2 , further comprising the following steps after the dispersing:
forming a CNT suspension having a first concentration and a CNTS/V2O5 suspension having a second concentration, respectively;
selecting a first volume of the CNT suspension and a second volume of the CNTS/V2O5 suspension; and
filtering the first volume of the CNT suspension and the second volume of the CNTs/V2O5 suspension through the polypropylene membrane.

5. The method of claim 1 , further comprising:
drying the flexible triple-layered membrane at a first temperature for a first predetermined time; and
punching the flexible triple-layered membrane into a round shape with a diameter.

6. The method of claim 1 , wherein the synthesizing comprises:
dispersing a first mass of ammonium metavanadate and a second mass of P123 (EO20PO70EO20) in a first volume of deionized (DI) water with a second volume of 2 molar (M) HC1 to form a mixture;
adding activated CNTs to the mixture and sonicating for a first time;
stirring the mixture at a room temperature for a second time;
transferring the mixture to an autoclave;
heating the mixture at a second temperature for a second predetermined time;
rinsing the mixture with the DI water and ethanol for three times; and
drying the mixture at a third temperature in vacuum.

7. The method of claim 1 , wherein the weight of the RSL on each separator is around 0.4-0.6 mg cm −2 .

Assignees

• Univ California
• Ford Cheer International Ltd

Inventors

• Lu Yunfeng
• Wang Jimmy
• Shen Li

Classifications

• H01M50/417

  Polyolefins · CPC title

• H01M2300/0094

  in the form of layered products, e.g. coatings · CPC title

• H01M4/762

  Porous or perforated metallic containers · CPC title

• H01M4/75

  Wires, rods or strips · CPC title

• H01M4/663

  containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres · CPC title