Conductive fibrous materials

Patent metadata

Field	Value
Publication number	US-10128503-B2
Application number	US-201414890410-A
Country	US
Kind code	B2
Filing date	May 12, 2014
Priority date	May 10, 2013
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

There is provided a conductive fibrous material comprising a plurality of carbonaceous fibers, wherein each carbonaceous fiber is fused to at least one other fiber. The carbonaceous fibers may be fused at fiber-to-fiber contact points by a polymer. The process of making the conductive fibrous material comprises mixing a phenolic polymer with a second polymer to form a polymer solution, preparing phenolic fibers having nano- or micro-scale diameters by electrospinning the polymer solution, and subsequent carbonization of the obtained phenolic fibers, thereby generating carbonaceous fibers, wherein each carbonaceous fiber is fused to at least one other fiber. The conductive fibrous material may be useful in electrode materials for energy storage devices.

First claim

The invention claimed is:

1. A conductive fibrous material comprising a plurality of carbonaceous fibers, wherein the carbonaceous fibers have a diameter of about 0.1 μm to about 15 μm and each carbonaceous fiber is fused to at least one other fiber, wherein the carbonaceous fibers are fused at fiber-to-fiber contact points by a low-melting point polymer selected from the group consisting of homo-polyether, co-polyether, co-polyether-polyester, and polymer blends thereof, wherein the weight ratio between a carbonaceous fiber precursor to polymer is from 99:1 to 80:20, and wherein the carbonaceous fibers are electrospun.

2. The material according to claim 1 , wherein a major portion of the carbonaceous fibers are fused at multiple fiber-to-fiber contact points.

3. The material according to claim 2 , wherein the polymer has a melting point of below 200° C.

4. The material according to claim 2 , wherein the polymer has a molecular weight from about 100,000 to 1,000,000.

5. The material according to claim 1 , wherein the polymer is selected from the group consisting of polyethylene oxide, polypropylene oxide, and poloxamer 407, preferably wherein the homo- or co-polyether is selected from the group consisting of homo-(polyalkylene oxide), co-(polyalkylene oxide), and poloxamer.

6. The material according to claim 1 , wherein the carbonaceous fiber precursor is a phenolic fiber, preferably wherein the carbonaceous fiber precursor is derived from lignin, and preferably wherein the lignin is selected from the group consisting of: organosolv lignin, softwood kraft lignin, hardwood kraft lignin and lignosulfonate.

7. The material according to claim 1 , wherein said material is doped with nitrogen, preferably wherein the content of nitrogen is in the range of 0.1% to 0%.

8. The material according to claim 1 , wherein the carbonaceous fibers have nano- or micro-scale diameters.

9. A process for forming a conductive fibrous material according to claim 1 , comprising:
(a) mixing a phenolic polymer with a second polymer to form a polymer solution, wherein the weight ratio of phenolic polymer to second polymer is selected as being from about 80 to 99 weight percent of phenolic polymer to about 1 to 20 weight percent of second polymer;
(b) preparing phenolic fibers having nano- or micro-scale diameters by electrospinning the polymer solution of step a);
(c) carbonizing the phenolic fibers obtained through step b), thereby generating carbonaceous fibers, wherein each carbonaceous fiber is fused to at least one other fiber, wherein the second polymer is a low melting point polymer selected from the group consisting of homo-polyether, co-polyether, co-polyether-polyester, and polymer blends thereof.

10. The process according to claim 9 , further comprising stabilizing the phenolic fibers prior to carbonization, preferably wherein the stabilizing comprises heat treating and oxidizing the phenolic fibers.

11. The process according to claim 9 , wherein the carbonizing comprises heat treating the phenolic fibers in an inert atmosphere.

12. The process according to claim 9 , comprising the step of selecting the phenolic polymer as being derived from lignin, preferably wherein the lignin is selected from the group consisting of: organosolv lignin, softwood kraft lignin, hardwood kraft lignin and lignosulfonate.

13. The process according to claim 9 , comprising the step of selecting the second polymer as having a melting point below 200° C.

14. The process according to claim 9 , wherein the second polymer has a molecular weight from about 100,000 to 1,000,000.

15. The process according to claim 9 , wherein the second polymer is selected from the group consisting of polyethylene oxide, polypropylene oxide, and poloxamer 407, preferably wherein the homo- or co-polyether is selected from the group consisting of homo-(polyalkylene oxide), co-(polyalkylene oxide), and poloxamer.

16. The process according to claim 9 , wherein the polymer solution of step a) further comprises a polar solvent, preferably wherein the polar solvent is selected from the group consisting of acetone, acetonitrile, N,N-dimethylformamide (DMF), tetrahydrofuran (THF), ethyl acetate (EtOAc), formamide, dimethyl sulfoxide (DMSO), acetamide water, ethanol, and methanol.

17. The process according to claim 9 , further comprising the step of doping the carbonaceous fibers with nitrogen.

18. An electronic device comprising the conductive fibrous material of claim 1 , a fibrous mat comprising the material according to claim 1 , or an electrode material for energy storage devices comprising the material of claim 1 .

Assignees

• Agency Science Tech & Res

Inventors

• Li Xu
• He Chao Bin
• Wang Suxi
• Wong Siew Yee
• Chen Shilin

Classifications

• H01M4/1393

  of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• D01F9/17

  from lignin · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title