Electrolysis transistor

• US 9,096,939 B2
• Filed: 05/29/2008
• Issued: 08/04/2015
• Est. Priority Date: 05/29/2007
• Status: Expired due to Fees

• Current Assignee: Transphorm, Inc (Kohlberg Kravis Roberts & Company LP)
• Original Assignee: Transphorm, Inc (Kohlberg Kravis Roberts & Company LP)
• Inventors: Mishra, Umesh, Lai, Rakesh, Shen, Likun, McCarthy, Lee, Parikh, Primit
• Primary Examiner(s): Wecker, Jennifer
• Application Number:
  US12/156,178
• Publication Number:
  US 20080296173A1
• Time in Patent Office: 2,623 Days
• Field of Search: 205/742, 205/628, 204/279, 204/280, 204/242, 204/270, 204/276
• US Class Current: 1/1
• CPC Class Codes: C25B 1/02 Hydrogen or oxygen
• CPC Class Codes: C25B 1/04 by electrolysis of water
• CPC Class Codes: C25B 1/55 Photoelectrolysis
• CPC Class Codes: C25B 11/00 Electrodes; Manufacture thereof not otherwise provided for
• CPC Class Codes: C25B 11/075 consisting of a single catalytic element or catalytic compound
• CPC Class Codes: C25B 15/00 Operating or servicing cells
• CPC Class Codes: C25B 9/65 Means for supplying current; Electrode connections; Electric inter-cell connections
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight

Abstract

An electrolysis transistor for providing high-density electrochemistry and products utilizing the same, and high-efficiency electrolysis and electrochemical processes is disclosed. The electrolysis transistor may comprise an electrolyte, one or more working electrodes for transferring charge to or from said electrolyte, and one or more gate structures for altering electrode over-voltage and modifying the barrier at the electrode-electrolyte interface, reducing the voltage necessary for electrolysis. An electrochemical or photo-electrochemical cell may incorporate one or more of these electrolysis transistors.

Claims

1. A device, comprising:

a first electrode and second electrode;

a gate structure coupled to an insulating material layer, wherein said insulating material layer prevents current from flowing from said gate structure, said gate structure electrically coupled to one of said first and second electrodes, wherein said gate structure is overhanging either said first or second electrode; and

a liquid electrolyte disposed between the electrodes and the gate structure, said liquid electrolyte configured to produce hydrogen or oxygen through electrolysis;

wherein the electric coupling is such that an electrical bias applied to said gate structure causes an electrical field formed in the electrolyte to lower an electrical potential barrier to electrolysis of the electrolyte, and a proximity of the gate structure to an active electrode surface of the first or second electrode is less than 100 nm, such that the electrical potential barrier to electrolysis is directly lowered at the electrode surface.

2. The device of claim 1, wherein said lowering of the electrical potential barrier reduces the voltage needed for electrolysis of said electrolyte;

wherein the electrical field formed in said electrolyte is caused by image charges in said first or second electrode induced from an electrical bias applied to said gate structure.

3. The device of claim 1, wherein said insulating material layer comprises silicon nitride.

4. The device of claim 1, wherein said first and second electrodes comprise a cathode and an anode;

wherein said gate structure and said first and second electrodes are disposed on a substrate.

5. The device of claim 1, wherein said first and second electrodes are formed on a substrate formed from a semiconductor material.

6. The device of claim 1, wherein said first and second electrodes are formed on a substrate comprised of conductive or insulating material.

7. The device of claim 1, wherein said first or second electrode comprises a roughened surface which enhances electrical field modification at said first or second electrode.

8. The device of claim 1, wherein at least one of said first and second electrodes is formed from GaN.

9. The device of claim 1, wherein at least one of said first and second electrodes beneath said suspended gate structure is etched to create a patterned surface beneath said gate, said patterned surface increasing the working surface contributing to electrolysis.

10. The device of claim 1, wherein said electrolysis occurs at a current density >

1 A/cm2, efficiency of >

40% in said electrolyte, and at room temperature and pressure, where said electrolyte is neutral.

11. The device of claim 1, wherein the peak current density is >

5 A/cm2.

12. The device of claim 1, wherein said first and second electrodes comprise an anode and a cathode in a stacked configuration.

13. The device of claim 1, wherein the electrolysis of said electrolyte disposed between said electrodes and gate structure causes commingled hydrogen and oxygen to be generated.

14. The device of claim 1, wherein said first and second electrodes comprise an anode and cathode that are separated in space.

15. The device of claim 14, wherein said spacing between said anode and cathode is less than 100 μ

m.

16. The device of claim 14, wherein said electrolysis causes spatially separated hydrogen and oxygen to be generated.

17. The device of claim 1, wherein one of said first and second electrodes is formed from Ti/Pt.

18. A method for increasing the efficiency of electrolysis of a liquid electrolyte, comprising:

providing a device having an electrode electrically coupled to a gate structure such that said gate structure is overhanging said electrode, having the electrolyte disposed therebetween, wherein the gate structure is coupled to an insulating material layer, said insulating material layer preventing current from flowing from said gate structure;

applying an electrical bias to said gate structure to modify an electric field and potential in a region between said electrolyte and said electrode or gate structure to lower an electrical potential barrier to electrolysis of said electrolyte disposed between said electrode and said gate structure; and

generating spatially separated hydrogen and oxygen from electrolysis of the electrolyte.

19. A method for increasing the efficiency of electrolysis of a liquid electrolyte, comprising:

providing a device having an electrode electrically coupled to a gate structure such that said gate structure is overhanging said electrode, having the electrolyte disposed therebetween, wherein the gate structure is coupled to an insulating material layer, said insulating material layer preventing current from flowing from said gate structure;

applying an electrical bias to said gate structure to modify an electric field and potential in a region between said electrolyte and said electrode or gate structure to lower an electrical potential barrier to electrolysis of said electrolyte disposed between said electrode and said gate structure; and

generating hydrogen from electrolysis of the electrolyte.