NANO-FEATURED POROUS SILICON MATERIALS

• US 20180331356A1
• Filed: 08/12/2016
• Published: 11/15/2018
• Est. Priority Date: 08/14/2015
• Status: Active Grant

• Current Assignee: Group14 Technologies Inc.
• Original Assignee: EnerG2 Technologies, Incorporated, Sakshaug J. Avery
• Inventors: Feaver, Aaron M., Thompkins, Leah A., Geramita, Katharine, Kron, Benjamin E., Sakshaug, Avery J., Fredrick, Sarah, Costantino, Henry R., Goodwin, Chad, Timmons, Christopher
• Granted Patent: US 10,763,501 B2
• Time in Patent Office: Days
• CPC Class Codes: C01B 33/021 Preparation chemical coating from the vapour phase C23C16/00
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/85 by XPS, EDX or EDAX data
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C01P 2006/11 Powder tap density
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/14 Pore volume
• CPC Class Codes: C01P 2006/16 Pore diameter
• CPC Class Codes: C01P 2006/17 Pore diameter distribution
• CPC Class Codes: C01P 2006/21 Attrition-index or crushing strength of granulates
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C23F 1/00 Etching metallic material by chemical means manufacture of printing surfaces B41C; manufacture of printed circuits H05K
• 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 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/366 as layered products
• 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: H01M 8/1037 : having silicon, e.g. sulfonated crosslinked polydimethylsiloxanes
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

Porous silicon and methods for preparation and use of the same are disclosed. The porous silicon materials have utility either alone or in combination with other materials, for example, combined with carbon particles for energy storage applications.

Claims

1. A nano-featured porous silicon material comprising a skeletal density less than 2.2 g/cm³ as measured by helium pcynometry.

2. The nano-featured porous silicon of claim 1, wherein the skeletal density is less than 2.1 g/cm³.

3. The nano-featured porous silicon of claim 1, wherein the skeletal density is less than 2.0 g/cm³.

4. The nano-featured porous silicon of any one of claims 1 to 3, having a friability greater than 10%

5. The nano-featured porous silicon of any one of claims 1 to 3, having a friability greater than 50%

6. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic thickness of nano features of less than 300 nm.

7. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic thickness of nano features of less than 100 nm.

8. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic thickness of nano features of less than 50 nm.

9. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic thickness of nano features of less than 30 nm.

10. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic thickness of nano features of less than 15 nm.

11. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic distance between silicon nano features of the nano features of less than 300 nm.

12. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic distance between silicon nano features of the nano features of less than 100 nm.

13. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic distance between silicon nano features of the nano features of less than 50 nm.

14. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic distance between silicon nano features of the nano features of less than 30 nm.

15. The nano-featured porous silicon of any one of claims 1 to 5, having a characteristic distance between silicon nano features of the nano features of less than 15 nm.

16. The nano-featured porous silicon of any one of claims 1-15, wherein the nano-featured porous silicon comprises a specific surface area between 30 and 230 m²/g and a pore volume between 0.1 and 0.5 cm³/g.

17. The nano-featured porous silicon of claim 16, wherein the nano-featured porous silicon comprises a specific surface area between 30 and 100 m²/g and a pore volume between 0.1 and 0.5 cm3/g.

18. The nano-featured porous silicon of any one of claims 1-17, wherein the nano-featured porous silicon comprises less than 40% micropores, between 30 and 40% mesopores, and between 20 and 30% macropores.

19. The nano-featured porous silicon of any one of claims 1-17, wherein the nano-featured porous silicon comprises less than 20% micropores, between 30 and 60% mesopores, and between 20 and 50% macropores.

20. The nano-featured porous silicon of any one of claims 1-17, wherein the nano-featured porous silicon comprises less than 10% micropores, between 40 and 70% mesopores, and between 20 and 50% macropores.

21. The nano-featured porous silicon of any one of claims 1-17, wherein the nano-featured porous silicon comprises less than 5% micropores, between 40 and 50% mesopores, and between 40 and 50% macropores.

22. The nano-featured porous silicon of any one of claims 1-17, wherein the nano-featured porous silicon comprises less than 2% micropores, between 40 and 50% mesopores, and between 50 and 60% macropores.

23. The nano-featured porous silicon of any one of claims 1-22, wherein the nano-featured porous silicon exhibits a capacity of at least 1600 mAh/g and an average Coulombic efficiency of at least 0.98 when tested in a lithium ion half-cell cycled between 0.8 V and 0.005 V, where the counter electrode is lithium metal, the electrolyte comprises 1M LiPF₆ in a solvent comprised of 2:

1 iethylene carbonate;

diethylcarbonate (EC;

DEC) and 10% (w/w) fluoroethylenecarbonate (FEC) and employing a polypropylene separator.

24. The nano-featured porous silicon of claim 23, wherein the nano-featured porous silicon exhibits a capacity of at least 2300 mAh/g and an average Coulombic efficiency of at least 0.97.

25. The nano-featured porous silicon of any one of claims 1-24, having an oxygen content from 1 to 20% by weight, and an aluminum content from 1 to 30% by weight.

26. The nano-featured porous silicon of claim 25, comprising from 1 to 10% by weight aluminum.

27. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 1000 nm.

28. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 800 nm.

29. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 300 nm.

30. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 150 nm.

31. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 100 nm.

32. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 50 nm.

33. The nano-featured porous silicon of any one of claims 1-26, wherein the nano-featured porous silicon comprises a Dv50 less than 15 nm.

34. The nano-featured porous silicon of any one of claims 1-15, having a surface area of 30 to 120 m2/g, a pore volume of 0.08 to 0.3 cm3/g, wherein the pore volume is comprised of 5 to 40% micropores, 35-70% mesopores, and 30-60% macropores.

35. The nano-featured porous silicon of any one of claims 1-15, having a surface area of 30 to 120 m2/g, a pore volume of 0.09 to 0.18 cm3/g, wherein the pore volume is comprised of 5 to 15% micropores, 45-55% mesopores, and 30-45% macropores.

36. An electrode comprising a nano-featured porous silicon according to any one of claims 1-35.

37. The electrode of claim 36, wherein the electrode is an anode.

38. An energy storage device comprising a nano-featured porous silicon according to any one of claims 1-35 or the electrode of claim 36 or 37.

39. The energy storage device of claim 38, wherein the energy storage device further comprises a lithium ion battery.

40. A method for producing nano-featured porous silicon particles comprising:

a) suspending particles of a silicon alloy in a liquid medium containing a dissolved acid;

b) storing the suspended particles for a period of time at sufficient temperature to allow for erosion of metal cations from the silicon alloy in to the liquid medium to yield porous silicon particles with nano-sized features; and

c) removing the liquid medium to yield dried porous silicon particles with nano-sized features.

41. The method of claim 40, wherein the particles of the silicon alloy comprise a silicon-aluminum alloy.

42. The method of claim 41, wherein the silicon-aluminum alloy particles comprise a Dv50 between 1 um and 20 um.

43. The method of claim 40, wherein the liquid medium comprises aqueous hydrochloric acid, and the temperature is between 25 and 100°

C.

44. The method of claim 41, wherein the Al in the alloy is present at less than 30% by weight.

45. The method of any one of claims 40-44, wherein the erosion of metal cations is conducted in a continuous feed reactor.

46. The method of any one of claims 40-44, wherein the erosion of metal cations is conducted in a dunk tank.

47. The method of any one of claims 40-44, wherein the liquid removal is accomplished by subjecting the porous silicon particles to centrifugation, vacuum, or elevated temperature, or combinations thereof.

48. A method for producing nano-featured porous silicon particles comprising:

a) heating particles of a silicon metal alloy at a temperature between 350 and 850 C in the presence of nitrogen;

b) holding the particles of a silicon metal alloy at a temperature between 350 and 850 C in the presence of an etching gas comprising chlorine, hydrochloric acid, fluorine, or combinations thereof, to allow for creation of a metal chloride, metal fluoride, or combinations thereof; and

c) cooling the mixture, and removing the metal chloride, metal fluoride, or combinations thereof, to yield a nano-featured porous silicon.