Structured silicon anode

• US 7,402,829 B2
• Filed: 11/05/2003
• Issued: 07/22/2008
• Est. Priority Date: 11/05/2002
• Status: Expired due to Fees

• Current Assignee: Nexeon Limited
• Original Assignee: Nexeon Limited
• Inventors: Green, Mino
• Primary Examiner(s): Jackson; Jerome
• Assistant Examiner(s): Valentine; Jami M
• Application Number:
  US10/533,822
• Publication Number:
  US 20060097691A1
• Time in Patent Office: 1,721 Days
• Field of Search: 257 1- 5, 438/809, 438/900, 320/107, 429/52
• US Class Current: 257/1
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/04 Processes of manufacture in general
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/1395 of electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• 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: Y10S 438/90 Bulk effect device making
• CPC Class Codes: Y10S 977/701 Integrated with dissimilar structures on a common substrate
• CPC Class Codes: Y10S 977/81 Of specified metal or metal alloy composition
• CPC Class Codes: Y10S 977/932 for electronic or optoelectronic application
• CPC Class Codes: Y10S 977/948 Energy storage/generating using nanostructure, e.g. fuel cell, battery
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A silicon/lithium battery can be fabricated from a silicon substrate. This allows the battery to be produced as an integrated unit on a chip. The battery includes a silicon anode formed from sub-micron diameter pillars of silicon fabricated on an n-type silicon wafer. The battery also includes a cathode including lithium.

Claims

1. An energy storage device comprising:

an anode comprising an array of sub-micron silicon structures supported on a silicon substrate; and

a cathode comprising lithium, arranged to form a battery.

2. A device according to claim 1 wherein the anode is arranged to tolerate the conditions occasioned by the volume changes caused by charging/discharging of the battery.

3. A device according to claim 1 wherein the anode is arranged to maintain structural integrity throughout the cycling of the battery.

4. A device according to claim 1 wherein the anode is arranged to withstand repeated volume expansion associated with alloying during use of the battery.

5. A device according to claim 1 wherein the array of sub-micron silicon structures comprise an array of sub-micron silicon pillars.

6. A device according to claim 5 wherein the pillars have a surface area of about 4 FH/d times the substrate area wherein F is the surface fractional coverage, H is the height of the pillar and d is the diameter of the pillar.

7. A device according to claim 5 in which the sub-micron pillars do not exceed a fractional coverage of 0.5 of the substrate.

8. A device according to claim 5 wherein the pillars are 0.1 to 1.0 microns in diameter and 1 to 10 microns in height.

9. A device according to claim 5 wherein the pillars are approximately 0.3 microns in diameter and 6 microns in height.

10. A device according to claim 1 in which the substrate comprises n-type silicon.

11. A device according to claim 1 made on a wafer-bonded silicon-on-insulator substrate.

12. A battery including a silicon anode comprising:

an array of sub-micron silicon pillars fabricated on a silicon substrate; and

a lithium cathode, wherein a compound film is formed on the silicon pillars in a charging step.

13. A battery according to claim 12 wherein the film is a Zintl-Phase Compound.

14. A battery according to claim 12 wherein the compound film is deformable so as not to give rise to significant stress-induced cracking during the volume change in a charging or discharging step.

15. An electrode for a battery comprising sub-micron silicon pillars supported on a silicon substrate and arranged to form a battery with a lithium cathode and a lithium-based electrolyte.