PRODUCTION

• US 20100196760A1
• Filed: 07/17/2008
• Published: 08/05/2010
• Est. Priority Date: 07/17/2007
• Status: Active Grant

• Current Assignee: Nexeon Limited
• Original Assignee: Nexeon Limited
• Inventors: Green, Mino
• Granted Patent: US 8,642,211 B2
• Time in Patent Office: Days
• US Class Current: 429/220
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/022 Electrodes made of one single microscopic fiber
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/0492 Chemical attack of the support material
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: H01M 4/626 Metals
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49115 including coating or impregnating
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]

Abstract

A pre-charged material including silicon-comprising fibres characterised in that two or more of the fibres are bonded together to create both a bonded felt anode structure, with or without a current collector, and a composite anode structure with a current collector and an electrode structure. The structure overcomes problems associated with charge/discharge capacity loss.

Claims

1. A pre-charged material comprising silicon-comprising fibres characterised in that two or more of the fibres are bonded together.

2. The material as claimed in claim 1 wherein the two or more bonded fibres are bonded via a metal bridging element.

3. The material as claimed in claim 2 wherein the metal bridging element is one or more selected from copper, nickel, aluminium, iron, iridium, gold, titanium, lead, bismuth, antimony and silver.

4. The material as claimed in claim 1 wherein substantially all of the fibres are bonded together.

5. The material as claimed in claim 1 in which the fibres have transverse dimensions in the range 0.08 to 0.5 microns, preferably 0.2 microns and a length in the range 20 to 300 microns preferably 100 microns.

6. The material as claimed in claim 1 in which the fibres have an aspect ratio of about 100:

1.

7. The material as claimed in claim 1 in which the fibres have a substantially circular cross-section.

8. The material as claimed in claim 1 in which the fibres have a substantially non-circular cross-section.

9. A method of fabricating a material comprising bonded silicon-comprising fibres as claimed in claim 1, comprising bonding two or more silicon-comprising fibres together

10. The method as claimed in claim 9 wherein the two or more fibres are bonded via excess pressure.

11. The method as claimed in claim 9 wherein the two or more fibres are bonded via elevated temperature.

12. The method as claimed in claim 9 wherein the two or more fibres are bonded via a metal bridging element.

13. The method as claimed in claim 12 wherein the metal bridging element is copper, nickel, aluminium, iron, iridium, gold, titanium, lead, bismuth, antimony and silver.

14. The method as claimed in claim 12 wherein the two or more silicon fibres are heated to the alloying temperature of silicon and the metal bridging element.

15. The method as claimed in claim 12 wherein the metal bridging element is added onto one or more of the silicon comprising fibres by electroless plating, dispersion of a small particle size powder or vapour deposition.

16. The method as claimed in claim 9 wherein the fibres are prepared by etching a substrate comprising silicon to make fibres and detaching the fibres from the substrate.

17. The method as claimed in claim 16 in which the pillars are created by reactive ion etching, chemical reaction etching or galvanic exchange etching.

18. The method as claimed in claim 16 in which the pillars are detached by one or more of scraping, agitating or chemical etching.

19. The method as claimed in claim 9 in which the silicon-comprising material comprises one of undoped silicon, doped silicon or a silicon germanium mixture.

20. The method as claimed in claim 9 in which the fibre is single crystal silicon, single crystal or silicon germanium.

21. The method of creating a cell electrode comprising depositing a slurry containing a material as claimed in claim 1 to form a layer of bonded silicon-comprising fibres.

22. The method of creating a cell electrode comprising depositing a slurry comprising silicon-comprising fibres onto a current collector and bonding two or more of the silicon-comprising fibres as claimed in claim 9.

23. The method as claimed in claim 21 in which the fibres are single crystal fibres.

24. The method as claimed in claim 21 in which the fibres are deposited in a bonded felt or a bonded composite.

25. The method as claimed in claim 21 including depositing the bonded fibres on a current collector.

26. The method as claimed in claim 21 in which the electrode is an anode.

27. The method as claimed in claim 21 in which the material has a percentage pore volume of about 10-30 percent.

28. A method of fabricating a lithium rechargeable cell comprising the steps of creating an anode as claimed in claim 21 and adding a cathode an electrolyte.

29. The method as claimed in claim 28 further comprising adding a separator between cathode and the anode.

30. The method as claimed in claim 28 further comprising providing a casing around the cell.

31. A composite electrode containing bonded silicon-comprising fibres according to claim 1.

32. A composite electrode as claimed in claim 31 which uses copper as a current collector.

33. A composite electrode as claimed in claim 31 in which the electrode is an anode.

34. An electrochemical cell containing an anode as claimed in claim 31.

35. The electrochemical cell as claimed in claim 34 in which the cathode comprises a lithium-containing compound capable of releasing and reabsorbing lithium ions as its active material.

36. The electrochemical cell as claimed in claim 35 in which the cathode comprises lithium-based metal oxide, sulphide or phosphate as its active material.

37. A lithium rechargeable cell anode comprising a bonded layer of silicon-comprising single crystal fibres.

38. An anode as claimed in claim 37 in which the fibres are the active components of a composite electrode.

39. An anode as claimed in claim 37 including amorphous silicon portions at intersections of the fibres.

40. A cell comprising an anode as claimed in claim 37 and a cathode.

41. A cell as claimed in claim 40 in which the cathode comprises lithium-based material.

42. A cell as claimed in claim 41 in which the cathode comprises lithium cobalt dioxide.

43. A device powered by a cell as claimed in claim 38.

44-50. -50. (canceled)