Positive electrode for sulfur-based batteries

Patent metadata

Field	Value
Publication number	US-2016149218-A1
Application number	US-201414555026-A
Country	US
Kind code	A1
Filing date	Nov 26, 2014
Priority date	Nov 26, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A positive electrode includes a sulfur-based active material, a binder, a conductive filler, and porous, one-dimensional metal oxide nanorods. The one-dimensional metal oxide nanorods are mixed, as an additive, throughout the positive electrode with the sulfur-based active material, the binder, and the conductive filler. The positive electrode with the porous, one-dimensional metal oxide nanorods may be incorporated into any sulfur-based battery.

First claim

What is claimed is:

1 . A positive electrode, comprising:
a sulfur-based active material; a binder; a conductive filler; and porous, one-dimensional metal oxide nanorods mixed throughout the positive electrode, as an additive, with the sulfur-based active material, the binder, and the conductive filler.

2 . The positive electrode as defined in claim 1 wherein the porous, one-dimensional metal oxide nanorods are not embedded within the sulfur-based active material, the binder, or the conductive filler.

3 . The positive electrode as defined in claim 1 wherein the porous, one-dimensional metal oxide nanorods include pores that are three-dimensional nanopores.

4 . The positive electrode as defined in claim 1 wherein the porous, one-dimensional metal oxide nanorods are present in an amount ranging from greater than 0 wt % to about 2 wt % based on a total wt % of the positive electrode material.

5 . The positive electrode as defined in claim 1 wherein each of the porous, one-dimensional metal oxide nanorods has a diameter ranging from about 10 nm to about 100 nm and a length ranging from about 10 nm to about 3 microns, wherein the diameter is less than the length.

6 . The positive electrode as defined in claim 1 wherein the porous, one-dimensional metal oxide nanorods include pores, each of the pores having a diameter ranging from about 2 nm to about 6 nm.

7 . The positive electrode as defined in claim 1 wherein the porous, one-dimensional metal oxide nanorods include a metal oxide selected from the group consisting of TiO 2 , Al 2 O 3 , ZrO 2 , SiO 2 , and combinations thereof.

8 . The positive electrode as defined in claim 1 wherein each of the porous, metal oxide nanorods has a surface area ranging from about 130 m 2 /g to about 500 m 2 /g.

9 . The positive electrode as defined in claim 1 wherein:
the sulfur-based active material is present in an amount ranging from about 50 wt % to about 95 wt % based on a total wt % of the positive electrode material;
the binder is present in an amount ranging from about 5 wt % to about 20 wt % based on the total wt % of the positive electrode material;
the conductive filler is present in an amount ranging from about 5 wt % to about 20 wt % based on the total wt % of the positive electrode material; and
the porous, one-dimensional metal oxide nanorods are present in an amount up to about 2 wt % based on the total wt % of the positive electrode material.

10 . The positive electrode as defined in claim 1 wherein the porous, one-dimensional metal oxide nanorods further include a doping agent selected from the group consisting of chromium ions, vanadium ions, zirconium ions, niobium ions, yttrium ions, silicon ions, or lanthanum ions.

11 . A sulfur-based battery, comprising:
a positive electrode, including:
a sulfur-based active material;
a binder;
a conductive filler; and
porous, one-dimensional metal oxide nanorods mixed throughout the positive electrode as an additive with the sulfur-based active material, the binder and the conductive filler;
a negative electrode; and a microporous polymer separator soaked in an electrolyte solution, the microporous polymer separator being disposed between the positive electrode and the negative electrode.

12 . The sulfur-based battery as defined in claim 11 wherein the porous, one-dimensional metal oxide nanorods are present in an amount ranging from greater than 0 wt % to about 2 wt % based on a total wt % of the positive electrode material.

13 . The sulfur-based battery as defined in claim 11 wherein the porous, one-dimensional metal oxide nanorods include a metal oxide selected from the group consisting of TiO 2 , Al 2 O 3 , ZrO 2 , SiO 2 , and combinations thereof.

14 . The sulfur-based battery as defined in claim 11 wherein:
the sulfur-based active material is a sulfur-carbon composite; and
the electrolyte solution includes an ether based solvent and a lithium salt dissolved in the ether based solvent, the ether based solvent being selected from the group consisting of 1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,2-dimethoxyethane, 1-2-diethoxyethane, ethoxymethoxyethane, tetraethylene glycol dimethyl ether (TEGDME), polyethylene glycol dimethyl ether (PEGDME), and mixtures thereof, and the lithium salt being selected from the group consisting of LiClO 4 , LiAlCl 4 , LiI, LiBr, LiB(C 2 O 4 ) 2 (LiBOB), LiBF 2 (C 2 O 4 ) (LiODFB), LiSCN, LiBF 4 , LiB(C 6 H 5 ) 4 , LiAsF 6 , LiCF 3 SO 3 , LiN(FSO 2 ) 2 (LIFSI), LiN(CF 3 SO 2 ) 2 (LITFSI), LiPF 6 , LiPF 4 (C 2 O 4 ) (LiFOP), LiNO 3 , and mixtures thereof.

15 . A method, comprising:
forming an aqueous mixture containing nanoparticles of a metal oxide starting material having one of i) a pH ranging from about 7 to about 10 or ii) a pH ranging from about 5 to about 7; performing hydrothermal synthesis using the aqueous mixture, thereby forming precursor nanostructures from the nanoparticles; and annealing the precursor nanostructures, thereby sintering the precursor nanostructures and vaporizing water from the precursor nanostructures to form porous, one-dimensional metal oxide nanorods.

16 . The method as defined in claim 15 wherein, after the hydrothermal synthesis, the method further includes doping the porous, one-dimensional metal oxide nanorods with lanthanum ions, vanadium ions, zirconium ions, niobium ions, yttrium ions, silicon ions or chromium ions.

17 . The method as defined in claim 15 wherein the hydrothermal synthesis includes subjecting the aqueous mixture to heat and vapor pressure in a closed system, thereby causing:
an amorphous layer to form on respective surfaces of at least some of the metal oxide nanoparticles;
the amorphous layers to recrystallize to form recrystallized metal oxide materials;
the recrystallized metal oxide materials to grow into nanosheets; and
the nanosheets to separate from the metal oxide nanoparticles to form the precursor nanostructures.

18 . The method as defined in claim 15 , further comprising adding the porous, one-dimensional metal oxide nanorods, as an additive, to a positive electrode composition including at least a sulfur-based active material.

19 . The method as defined in claim 18 , further comprising:
removing the precursor nanostructures and any liquid present after the hydrothermal synthesis from the closed system prior to annealing the precursor nanostructures; and wherein annealing the precursor nanostructures occurs at a temperature ranging from about 350° C. to about 700° C. for a time ranging from about 3 hours to about 5 hours, thereby vaporizing the water to form the porous, one-dimensional metal oxide nanorods.

20 . The method as defined in claim 15 wherein the porous, one-dimensional metal oxide nanorods include a metal oxide selected from the group consisting of TiO 2 , Al 2 O 3 , ZrO 2 , and a combination thereof.

Assignees

• Gm Global Tech Operations Inc

Inventors

• Liu Zhongyi
• Xiao Qiangfeng
• Cai Mei
• Carpenter Michael K

Classifications

• H01M10/054

  Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium · CPC title

• H01M4/624

  Electric conductive fillers · CPC title

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M4/38 Primary

  of elements or alloys · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title