Electrode including silicon-comprising fibres and electrochemical cells including the same

• US 8,642,211 B2
• Filed: 07/17/2008
• Issued: 02/04/2014
• Est. Priority Date: 07/17/2007
• Status: Active Grant

• Current Assignee: Nexeon Limited
• Original Assignee: Nexeon Limited
• Inventors: Green, Mino
• Primary Examiner(s): HENDRICKSON, STUART L
• Application Number:
  US12/669,237
• Publication Number:
  US 20100196760A1
• Time in Patent Office: 2,028 Days
• Field of Search: 429/218.1, 429/231.95
• US Class Current: 429/218.1
• 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 fibers characterized in that two or more of the fibers 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. An electrode comprising silicon-comprising fibres, wherein the silicon-comprising fibres are arranged to cross over each other to provide multiple intersection points, and characterized in that two or more of the fibres are bonded to each other at intersection points to form a bonded felt before any lithiation or delithiation of the silicon comprising fibres, and wherein the two or more fibres are made of the same material and have substantially the same dimensions.

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

3. The electrode as claimed in claim 1 in which the fibres have transverse dimensions in the range 0.08 to 0.5 microns and a length in the range 20 to 300 microns.

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

1.

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

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

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

8. A composite electrode as claimed in claim 7 which uses copper as a current collector.

9. A composite electrode as claimed in claim 7 in which the electrode is an anode.

10. An electrochemical cell containing a composite electrode as claimed in claim 7, wherein the composite electrode is an anode.

11. The electrochemical cell as claimed in claim 10 further comprising a cathode in which the cathode comprises a lithium-containing compound capable of releasing and reabsorbing lithium ions as its active material.

12. The electrochemical cell as claimed in claim 11 in which the cathode comprises lithium-based metal oxide, sulphide or phosphate as its active material.

13. A lithium rechargeable cell anode comprising a layer of silicon-comprising fibres, wherein the silicon comprising fibres are arranged to cross over each other to provide multiple intersection points and characterized in that two or more of the fibres are bonded to each other at intersection points to form a bonded felt before any lithiation or delithiation of the silicon-comprising fibres, and wherein the fibres are single crystal fibres.

14. An anode as claimed in claim 13 in which the fibres are the active components of a composite electrode.

15. An anode as claimed in claim 13 including amorphous silicon portions at intersections of the fibres.

16. A cell comprising an anode as claimed in claim 13 and a cathode.

17. A cell as claimed in claim 16 in which the cathode comprises lithium-based material.

18. A cell as claimed in claim 17 in which the cathode comprises lithium cobalt dioxide.

19. A device powered by a cell as claimed in claim 16.

20. An electrode for a lithium ion battery comprising an electrochemically active material comprising a layer of silicon-comprising fibres, wherein the silicon-comprising fibres are arranged to cross over each other to provide multiple intersection points, and characterized in that at least two of the silicon-comprising fibres are bonded to each other at intersection points to form a bonded felt before any lithiation or delithiation of the electrochemically active material.

21. The electrode as claimed in claim 20 wherein a plurality of fibres are bonded together.

22. The electrode as claimed in claim 20 in which the fibres have transverse dimensions in the range 0.08 to 0.5 microns and a length in the range 20 to 300 microns.

23. The electrode as claimed in claim 20 in which the fibres have an aspect ratio of about 100:

1.

24. The electrode as claimed in claim 20 in which the fibres have a substantially circular cross-section.

25. The electrode as claimed in claim 20 in which the fibres have a substantially non-circular cross-section.

26. The electrode as claimed in claim 20 which uses copper as a current collector.

27. The electrode as claimed in claim 20 in which the electrode is an anode.

28. An electrochemical cell containing an electrode as claimed in claim 27.

29. The electrochemical cell as claimed in claim 28 further comprising a cathode in which the cathode comprises a lithium-containing compound capable of releasing and reabsorbing lithium ions as its active material.

30. The electrochemical cell as claimed in claim 29 in which the cathode comprises lithium-based metal oxide, sulphide or phosphate as its active material.

31. The electrochemical cell as claimed in claim 30 in which the cathode comprises lithium cobalt dioxide.

32. The electrode of claim 20 wherein at least one of the silicon comprising fibres is a single crystal fibre.

33. The electrode of claim 20 including amorphous silicon portions at intersections of the fibres.