Structured silicon anode

• US 20060097691A1
• Filed: 11/05/2003
• Published: 05/11/2006
• Est. Priority Date: 11/05/2002
• Status: Active Grant

• Current Assignee: Nexeon Limited
• Original Assignee: Nexeon Limited
• Inventors: Green, Mino
• Granted Patent: US 7,402,829 B2
• Time in Patent Office: Days
• US Class Current: 320/107
• 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 submicron diameter pillars of silicon fabricated on an end-type silicon wafer.

Claims

1. An integrated silicon electrode for a battery, comprising a regular or irregular array of sub-micron silicon structures fabricated on a silicon substrate.

2. A silicon anode comprising an electrode according to claim 1, in which the sub-micron silicon structures comprise pillars of silicon fabricated on an n-type silicon substrate.

3. A silicon anode according to claim 2 made on a wafer-bonded silicon-on-insulator substrate.

4. A silicon anode according to claim 2 in which the silicon pillars do not exceed a fractional coverage of 0.5 of the substrate.

5. A silicon electrode according to claim 1 formed by the steps of:

(a) depositing a very thin film of a highly soluble solid onto a flat hydrophilic silicon substrate;

(b) exposing the film to solvent vapour under controlled conditions so that the film reorganizes into an array of discrete hemispherical islands on the surface; and

(c) reactively ion etching the silicon substrate with the islands of highly soluble solid acting as a resist so that the exposed silicon is etched away leaving pillars corresponding to the islands.

6. A silicon anode according to claim 2 wherein the pillars are 0.1-1.0 microns in diameter (d) and 1-10 microns in height (H).

7. A silicon anode according to claim 6 wherein the pillars are about 0.3 microns in diameter (d) and about 6 microns in height (H).

8. A lithium battery including an anode in accordance with claim 1.