Electrode active material of lithium ion battery and method for making the same

Patent metadata

Field	Value
Publication number	US-9240589-B2
Application number	US-201314070647-A
Country	US
Kind code	B2
Filing date	Nov 4, 2013
Priority date	Oct 17, 2013
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

A method for making an electrode active material of a lithium ion battery is provided. A sulfur grafted poly(pyridinopyridine) is synthesized. The sulfur grafted poly(pyridinopyridine) includes a poly(pyridinopyridine) matrix and a plurality of poly-sulfur groups dispersed in the poly(pyridinopyridine) matrix. The electrically conductive polymer is coated on a surface of the sulfur grafted poly(pyridinopyridine). An electrode active material of a lithium ion battery is also provided.

First claim

What is claimed is:

1. A method for making an electrode active material of a lithium ion battery comprising steps of:
synthesizing sulfur grafted poly(pyridinopyridine) comprising a poly(pyridinopyridine) matrix and a plurality of poly-sulfur groups dispersed in the poly(pyridinopyridine) matrix; and
coating a surface of the sulfur grafted poly(pyridinopyridine) with an electrically conductive polymer.

2. The method of claim 1 , wherein the synthesizing sulfur grafted poly(pyridinopyridine) comprises steps of:
mixing an elemental sulfur with a polyacrylonitrile to form a mixture;
sintering the mixture in vacuum or a protective gas at a temperature of about 250° C. to about 500° C., to form a sulfur containing composite; and
heating the sulfur containing composite to a temperature above a sublimation temperature of the elemental sulfur to remove at least a part of an un-reacted elemental sulfur from the sulfur containing composite.

3. The method of claim 2 , wherein the sintering the mixture is in a sealed container filled with the protective gas at a temperature of about 320° C. to about 400° C.

4. The method of claim 1 , wherein the synthesizing sulfur grafted poly(pyridinopyridine) comprises steps of:
mixing elemental sulfur with a polyacrylonitrile to form a mixture;
heating the mixture in vacuum or a protective gas at a heating temperature of about 250° C. to about 500° C., to form a sulfur containing composite; and
reacting the sulfur containing composite with a reducing agent for elemental sulfur in a liquid phase medium to remove un-reacted elemental sulfur from the sulfur containing composite.

5. The method of claim 4 , wherein the reducing agent is at least one of potassium borohydride and hydrazine.

6. The method of claim 4 , wherein a mass ratio of the elemental sulfur and the polyacrylonitrile is in a range from about 1:2 to about 10:1.

7. The method of claim 4 , wherein the reacting the sulfur containing composite with a reducing agent for elemental sulfur comprises steps of:
introducing the sulfur containing composite into a container having the liquid phase medium filled therein;
uniformly dispersing the sulfur containing composite in the liquid phase medium through mechanical stirring or ultrasonic vibration;
adding the reducing agent into the container while continuously mechanically stirring or ultrasonically vibrating the liquid phase medium, to dissolve the reducing agent in the liquid phase medium and react the reducing agent with the sulfur containing composite; and
separating the sulfur grafted poly(pyridinopyridine) from the liquid phase medium and purifying the sulfur grafted poly(pyridinopyridine).

8. The method of claim 7 , wherein the liquid phase medium is heated at a temperature in a range from about 90° C. to about 150° C.

9. The method of claim 4 , wherein the reacting the sulfur containing composite with a reducing agent for elemental sulfur comprises steps of:
introducing the sulfur containing composite with the reducing agent into a container having the liquid phase medium filled therein;
mechanically stirring or ultrasonically vibrating the liquid phase medium to uniformly disperse the sulfur containing composite in the liquid phase medium while dissolving the reducing agent in the liquid phase medium and reacting the reducing agent with the sulfur containing composite; and
separating the sulfur grafted poly(pyridinopyridine) from the liquid phase medium and purifying the sulfur grafted poly(pyridinopyridine).

10. The method of claim 1 , wherein the coating comprises:
mixing the sulfur grafted poly(pyridinopyridine), a monomer of the electrically conductive polymer, an oxidizing agent, and a surfactant in a liquid phase solvent to form a mixture; and
polymerizing the monomer of the electrically conductive polymer in the liquid phase solvent to synthesize the electrically conductive polymer coating layer on the surface of the sulfur grafted poly(pyridinopyridine).

11. The method of claim 10 further comprising a step of adding a doping agent to the mixture.

12. The method of claim 10 , wherein the electrically conductive polymer is selected from the group consisting of polythiophene, polyaniline, polyacetylene, polypyrrole, polyacene, polyphenylene, poly(p-phenylene vinylene), polydiacetylene, and combinations thereof.

13. The method of claim 10 , wherein the oxidizing agent is selected from the group consisting of ferric chloride, ammonium persulfate, ferric sulfate, and combinations thereof.

14. The method of claim 11 , wherein the doping agent is selected from the group consisting of sodium dodecyl sulfonate, sodium p-toluenesulfonate, and combinations thereof.

15. An electrode active material of a lithium ion battery comprising sulfur grafted poly(pyridinopyridine) and an electrically conductive polymer coated on a surface thereof, wherein the sulfur grafted poly(pyridinopyridine) comprises a poly(pyridinopyridine) matrix and sulfur dispersed in the poly(pyridinopyridine) matrix.

16. The electrode active material of claim 15 , wherein the sulfur is a poly-sulfur group consisting of one or more sulfur elements, represented by a formula of S x , and x is an integer between 1 and 8.

17. The electrode active material of claim 15 , wherein the sulfur is elemental sulfur composited with the poly(pyridinopyridine) matrix, the elemental sulfur has a shape of particles or grains, and one elemental sulfur particle is one sulfur molecule or a sulfur atom cluster consisting of a plurality of sulfur atoms.

18. The electrode active material of claim 15 , wherein the electrically conductive polymer is selected from the group consisting of polythiophene, polyaniline, polyacetylene, polypyrrole, polyacene, polyphenylene, poly(p-phenylene vinylene), polydiacetylene, and combinations thereof.

Assignees

• Univ Tsinghua
• Hon Hai Prec Ind Co Ltd

Inventors

• He xiang-ming
• Wang Li
• Li Jian-Jun
• Gao Jian

Classifications

• H01M4/1399

  of electrodes based on electro-active polymers · CPC title

• H01M4/608

  containing heterocyclic rings · CPC title

• H01M4/0402 Primary

  Methods of deposition of the material · CPC title

• H01M4/137

  Electrodes based on electro-active polymers · CPC title

• H01M4/366 Primary

  as layered products · CPC title