Method for manufacturing a polyacrylonitrile-sulfur composite material

Patent metadata

Field	Value
Publication number	US-10096834-B2
Application number	US-201314406267-A
Country	US
Kind code	B2
Filing date	May 3, 2013
Priority date	Jun 8, 2012
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A method is provided for manufacturing a polyacrylonitrile-sulfur composite material, the polyacrylonitrile-sulfur composite material having an sp2 hybrid proportion, with respect to the total carbon atoms included in the composite material, of greater than or equal to 85% including the method steps: a) reaction of polyacrylonitrile with sulfur at a temperature of greater than or equal to 450° C., in particular greater than or equal to 550° C.; b) immediate purification of the product obtained in method step a); and c) drying the purified product, if necessary. A composite material manufactured in this way may be used in particular in an active material of a cathode of a lithium-ion battery and offers a particularly high rate capacity. In addition, methods are provided for manufacturing an active material for an electrode, a polyacrylonitrile-sulfur composite material and an energy store.

First claim

What is claimed is:

1. A method for manufacturing a polyacrylonitrile-sulfur composite material, wherein the polyacrylonitrile-sulfur composite material has an sp 2 hybrid proportion greater than or equal to 85% with respect to the total carbon atoms included in the composite material, the method comprising:
a) reacting polyacrylonitrile with sulfur at a first temperature of greater than or equal to 550° C., wherein the sulfur is used in excess;
b) immediately removing the excess sulfur from a product obtained in method step a) by purifying the product; and
c) drying the purified product.

2. The method as recited in claim 1 , wherein the purification according to method step b) is carried out by a Soxhlet extraction.

3. The method as recited in claim 2 , wherein the Soxhlet extraction is carried out using an organic solvent.

4. The method as recited in claim 1 , wherein at least method step a) is carried out under an inert gas atmosphere.

5. The method as recited in claim 1 , wherein during method step a) a cyclized polyacrylonitrile reacts with sulfur to form a polyacrylonitrile-sulfur composite material having an sp 2 hybrid proportion of greater than or equal to 85%, the cyclized polyacrylonitrile being obtained through a reaction of polyacrylonitrile to cyclized polyacrylonitrile.

6. The method as recited in claim 1 , wherein polyacrylonitrile is reacted with sulfur in the presence of a catalyst.

7. The method as recited in claim 1 , wherein a weight ratio of sulfur to polyacrylonitrile is greater than or equal to 2:1.

8. A method for manufacturing an active material for an electrode, including a method for manufacturing a polyacrylonitrile-sulfur composite material, wherein the polyacrylonitrile-sulfur composite material has an sp 2 hybrid proportion greater than or equal to 85% with respect to the total carbon atoms included in the composite material, the method comprising:
a) reacting polyacrylonitrile with sulfur at a temperature of greater than or equal to 550° C., wherein the sulfur is used in excess;
b) immediately removing the excess sulfur from a product obtained in method step a) by purifying the product; and
c) drying the purified product.

9. The method as recited in claim 8 , wherein the electrode is a cathode of a lithium-sulfur battery.

10. The method as recited in claim 8 , wherein the method furthermore includes the following method step:
d) admixing at least one electrically conductive additive to the polyacrylonitrile-sulfur composite material.

11. The method as recited in claim 10 , wherein the additive includes one of carbon black, graphite, carbon fibers, carbon nanotubes, and mixtures thereof.

12. The method as recited in claim 10 , wherein the method furthermore includes the following method step:
e) admixing at least one binder to the polyacrylonitrile composite material.

13. The method as recited in claim 12 wherein the binder includes at least one of polyvinylidene fluoride and polytetrafluoroethylene.

14. The method as recited in claim 12 , wherein
in method step d) and in method step e), greater than or equal to 60 wt.-% to less than or equal to 90 wt.-% polyacrylonitrile-sulfur composite material is used,
in method step d), greater than or equal to 0.1 wt.-% to less than or equal to 30 wt.-% electrically conductive additives are admixed, and
in method step e), greater than or equal to 0.1 wt.-% to less than or equal to 30 wt.-% binders are admixed.

15. A polyacrylonitrile-sulfur composite material, manufactured using a method for manufacturing a polyacrylonitrile-sulfur composite material, wherein the polyacrylonitrile-sulfur composite material has an sp 2 hybrid proportion greater than or equal to 85% with respect to the total carbon atoms included in the composite material, the method comprising:
a) reacting polyacrylonitrile with sulfur at a temperature of greater than or equal to 550° C., wherein the sulfur is used in excess;
b) immediately removing the excess sulfur from a product obtained in method step a) by purifying the product; and
c) drying the purified product.

16. A method of using a polyacrylonitrile-sulfur composite material manufactured using a method for manufacturing a polyacrylonitrile-sulfur composite material, wherein the polyacrylonitrile-sulfur composite material has an sp 2 hybrid proportion greater than or equal to 85% with respect to the total carbon atoms included in the composite material, the manufacturing method comprising:
a) reacting polyacrylonitrile with sulfur at a temperature of greater than or equal to 550° C., wherein the sulfur is used in excess;
b) immediately removing the excess sulfur from a product obtained in method step a) by purifying the product; and
c) drying the purified product,
wherein the polyacrylonitrile-sulfur composite material is used as an active material in an electrode.

17. The method as recited in claim 16 , wherein the electrode is a cathode of a lithium-ion battery.

18. An energy store, comprising an electrode with an active material which includes a polyacrylonitrile-sulfur composite material manufactured using a method for manufacturing a polyacrylonitrile-sulfur composite material, wherein the polyacrylonitrile-sulfur composite material has an sp 2 hybrid proportion greater than or equal to 85% with respect to the total carbon atoms included in the composite material, the method comprising:
a) reacting polyacrylonitrile with sulfur at a temperature of greater than or equal to 550° C., wherein the sulfur is used in excess;
b) immediately removing the excess sulfur from a product obtained in method step a) by purifying the product; and
c) drying the purified product.

19. The energy store as recited in claim 18 , wherein the energy store includes a lithium-sulfur battery.

20. The method as recited in claim 12 , wherein
in method step d) and in method step e), greater than or equal to 65 wt.-% to less than or equal to 75 wt.-% polyacrylonitrile-sulfur composite material is used,
in method step d), greater than or equal to 5 wt.-% to less than or equal to 20 wt.-% electrically conductive additives are admixed, and
in method step e), greater than or equal to 5 wt.-% to less than or equal to 20 wt.-% binders are admixed.

21. The method as recited in claim 1 , wherein the method furthermore includes a method step, after method step a) and before method step b), of further reacting polyacrylonitrile with sulfur at a second temperature that is higher than the first temperature.

Assignees

• Bosch Gmbh Robert

Inventors

• Tenzer Martin
• Rolff Malte
• Fanous Jean

Classifications

• H01M4/604 Primary

  containing aliphatic main chain polymers · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• C08F120/44

  Acrylonitrile · CPC title

• H01M4/623

  fluorinated polymers · CPC title