HIGH-CAPACITY NANOSTRUCTURED GERMANIUM-CONTAINING MATERIALS AND LITHIUM ALLOYS THEREOF

• US 20100190059A1
• Filed: 04/22/2004
• Published: 07/29/2010
• Est. Priority Date: 04/22/2004
• Status: Active Grant

• Current Assignee: California Institute of Technology, Centre National De La Recherche Scientifique
• Original Assignee: California Institute of Technology, Centre National De La Recherche Scientifique
• Inventors: Yazami, Rachid, Graetz, Jason A., Ahn, Channing, Fultz, Brent T.
• Granted Patent: US 7,781,102 B2
• Time in Patent Office: Days
• US Class Current: 429/231.95
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/405 Alloys based on lithium
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Electrodes comprising an alkali metal, for example, lithium, alloyed with nanostructured materials of formula Si_zGe_(z-1), where 0<z≦1; formula Si_zGe_(z-1), where 0<z<1; and/or germanium exhibit a combination of improved capacities, cycle lives, and/or cycling rates compared with similar electrodes made from graphite. These electrodes are useful as anodes for secondary electrochemical cells, for example, batteries and electrochemical supercapacitors.

Claims

1. (canceled)

3. (canceled)

4-7. -7. (canceled)

16. (canceled)

17. (canceled)

19. A secondary electrochemical cell comprising an anode, a cathode, and an electrolyte, wherein the anode comprises nanostructured material of formula Si_(1-z)Ge_z or a lithium alloy thereof, wherein 0<

z≦

1.

20. The secondary electrochemical cell of claim 19, wherein the secondary electrochemical cell is an electrochemical supercapacitor.

21. The secondary electrochemical cell of claim 19, wherein the secondary electrochemical cell is fabricated on an integrated device.

22-29. -29. (canceled)

30-40. -40. (canceled)

41-50. -50. (canceled)

53. (canceled)

55. (canceled)

56-63. -63. (canceled)

64. An electrode for a secondary electrochemical cell, the electrode comprising a substrate and a layer of nanostructured framework material which adheres to the substrate, the framework material being in the form of an amorphous nanofilm of silicon-germanium material of formula Si_(1-z)Ge_z, wherein z is from 0.25 to 0.75 and wherein the electrode is the anode of a secondary electrochemical cell comprising an anode, a cathode and an electrolyte, the framework material of the electrode being disposed to allow interaction with the electrolyte.

2. The electrode of claim 64 wherein the framework material is alloyed with an alkali metal.

8. The electrode of claim 64, wherein the nanofilm has a thickness of not greater than about 500 nm.

9. The electrode of claim 8, wherein the nanofilm has a thickness of not greater than about 200 nm.

10. The electrode of claim 9, wherein the nanofilm has a thickness of not greater than about 100 nm.

11. The electrode of claim 2, wherein the alkali metal is lithium and the lithium alloy of the nanostructured material has the formula Li_xSi_(1-z)Ge_z, wherein x is at least about 1.

12. The electrode of claim 11, wherein the lithium alloy of the nanostructured material has the formula Li_xSi_(1-z)Ge_z, wherein x is at least about 2.5.

13. The electrode of claim 64, wherein the nanostructured material has a cycle life that is stable over at least about 10 cycles.

14. The electrode of claim 13, wherein the nanostructured material has a cycle life that is stable over at least about 20 cycles.

15. The electrode of claim 64, wherein the nanostructured material exhibits a rate capability of at least about 1 C.

18. The electrode of claim 64, wherein the substrate is a current collector and is made from a metal.

51. The electrode of claim 64 wherein z is from 0.5 to 0.75.

52. The electrode of claim 64, wherein the substrate serves as a current collector.

73. The electrode of claim 64, wherein the silicon-germanium material is a solid solution of silicon and germanium.

74. The electrode of claim 64, wherein the silicon-germanium material is not homogeneous.

65. (canceled)

66. An electrode for a secondary electrochemical cell, the electrode comprising an alkali metal alloy of nanostructured silicon-germanium material of formula Si_(1-z)Ge_z wherein z is from 0.25 to 0.75, the alkali metal alloy being produced by electrochemically alloying an alkali metal with an amorphous nanofilm of the material of formula Si_(1-z)Ge_z and wherein the electrode is the anode of a secondary electrochemical cell comprising an anode, a cathode and an electrolyte, the alkali metal alloy of the electrode nanofilm being disposed to allow interaction with the electrolyte.

54. The electrode of claim 66, where the thickness of the nanofilm is no greater than 500 nm.

69. The electrode of claim 66 wherein the alkali metal is lithium.

75. The electrode of claim 66, wherein the silicon-germanium material is a solid solution of silicon and germanium.

76. The electrode of claim 66, wherein the silicon-germanium material is not homogenous.

77. The electrode of claim 66, wherein the alkali metal is lithium and the lithium alloy has the formula Li_xSi_(1-z)Ge_z, wherein x is at least about 1.

67-68. -68. (canceled)

70-72. -72. (canceled)