HIGH CAPACITY MONOLITHIC COMPOSITE SI/CARBON FIBER ELECTRODE ARCHITECTURES SYNTHESIZED FROM LOW COST MATERIALS AND PROCESS TECHNOLOGIES

• US 20140038042A1
• Filed: 09/09/2013
• Published: 02/06/2014
• Est. Priority Date: 08/06/2012
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: RIOS, Orlando, DANIEL, Claus, TENHAEFF, Wyatt Evan, MARTHA, Surendra K.
• Granted Patent: US 9,929,400 B2
• Time in Patent Office: Days
• US Class Current: 429/211
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/1393 of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/1395 of electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]

Abstract

A composite Si-carbon fiber comprising a carbon matrix material with 1-90 wt % silicon embedded therein. The composite carbon fibers are incorporated into electrodes for batteries. The battery can be a lithium ion battery. A method of making an electrode incorporating composite Si-carbon fibers is also disclosed.

Claims

1. A composite Si-carbon fiber comprising a carbon matrix material with 1-90 wt % silicon embedded therein.

2. The composite Si-carbon fiber of claim 1, comprising 1-30 wt % silicon embedded therein.

3. The composite Si-carbon fiber of claim 1, wherein the carbon fiber has a diameter of 10-200 μ

m and a length of at least 3 times the diameter.

4. The composite Si-carbon fiber of claim 1, wherein the carbon fiber has a diameter of 50-100 μ

m and a length of at least 3 times the diameter.

5. The composite Si-carbon fiber of claim 1, wherein the silicon is crystalline with crystals of between 5 nm-200 μ

m in size.

6. The composite Si-carbon fiber of claim 1, wherein the silicon is amorphous with particles of between 5 nm-200 μ

m in size.

7. The composite Si-carbon fiber of claim 1, wherein the carbon matrix material is derived from lignin.

8. The composite Si-carbon fiber of claim 1, wherein the carbon matrix material comprises an aromatic backbone polymer with a carbon char yield above 30 wt %.

9. The composite Si-carbon fiber of claim 1, wherein the carbon matrix material is derived from polyacrylonitrile.

10. The composite Si-carbon fiber of claim 1, wherein the carbon matrix material has a density of 2.0 g/cm3 or less.

11. The composite Si-carbon fiber of claim 1, wherein the carbon matrix material has a density of at least 1.7 g/cm3.

12. The composite Si-carbon fiber of claim 1, wherein the silicon is completely embedded inside the carbon fiber.

13. An electrode for a battery, comprising a composite Si-carbon fiber comprising a carbon matrix material with 1-90 wt % silicon embedded therein.

14. The electrode of claim 13, comprising 1-30 wt % silicon embedded therein.

15. The electrode of claim 13, wherein the composite Si-carbon fiber has a diameter of 10-200 μ

m and a length of at least 3 times the diameter.

16. The electrode of claim 13, wherein the composite Si-carbon fiber has a diameter of 50-100 μ

m and a length of at least 3 times the diameter.

17. The electrode of claim 13, wherein the silicon is crystalline with crystals of between 5 nm-200 μ

m in size.

18. The electrode of claim 13, wherein the silicon is amorphous with particles of between 5 nm-200 μ

m in size.

19. The electrode of claim 13, wherein the carbon matrix material is derived from lignin.

20. The electrode of claim 13, wherein the carbon matrix material comprises an aromatic backbone polymer with a carbon char yield above 30 wt %.

21. The electrode of claim 13, wherein the carbon matrix material is derived from polyacrylonitrile.

22. The electrode of claim 13, wherein the carbon matrix material has a density of 2.0 g/cm3 or less.

23. The electrode of claim 13, wherein the carbon matrix material has a density of at least 1.7 g/cm3.

24. The electrode of claim 13, wherein the silicon is completely embedded inside the composite Si-carbon fiber.

25. The electrode of claim 13, wherein the electrode has a reversible energy storage capacity of 350 mAh/g to 4000 mAh/g.

26. The electrode of claim 13, wherein the silicon is uniformly distributed throughout the bulk of the composite Si-carbon fiber.

27. The electrode of claim 13, wherein the electrode has a reversible energy storage capacity of 350 mAh/g to 3500 mAh/g.

28. The electrode of claim 13, further comprising a binder.

29. The electrode of claim 13, further comprising a conductive additive.

30. The electrode of claim 13, further comprising a current collector.

31. The electrode of claim 13, wherein the fibers are fused together in the absence of a binder.

32. The electrode of claim 13, wherein the fibers are fused together and in the absence of a current collector.

33. The electrode of claim 13, wherein the composite Si-carbon fibers are provided with a binder and a conductive additive and coated onto a support.

34. The electrode of claim 33, wherein the support is a current collector.

35. A battery comprising an electrode, the electrode comprising composite Si-carbon fibers comprising a carbon matrix material with 1-90 wt % silicon embedded therein.

36. A method of making an electrode for a battery, comprising the steps of:

providing carbon matrix material;

mixing silicon particles with the carbon matrix material to form a carbon-silicon mixture;

forming composite Si-carbon fibers from the carbon-silicon mixture wherein the silicon is embedded in the fibers; and

,

forming the carbon-silicon composite fibers into an electrode.

37. The method of claim 36, wherein the composite Si-carbon fibers are mixed with a binder to form the electrode.

38. The method of claim 36, wherein the composite Si-carbon fibers are mixed with carbon black to form the electrode.

39. The method of claim 36, wherein the composite Si-carbon fibers are mixed with carbon black and a binder to form an electrode.

40. The method of claim 39, wherein the binder is a polymeric binder.

41. The method of claim 39, wherein the binder is Li—

C.

42. The method of claim 36, wherein the composite Si-carbon fibers are fused together to form a mat.