Lithium microbattery and fabrication method thereof

• US 8,475,963 B2
• Filed: 03/04/2010
• Issued: 07/02/2013
• Est. Priority Date: 03/16/2009
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Oukassi, Sami, Salot, Raphael, Dunoyer, Nicolas, Martin, Steve
• Primary Examiner(s): Huff, Mark F
• Assistant Examiner(s): WILLS, MONIQUE M
• Application Number:
  US13/203,796
• Publication Number:
  US 20110311883A1
• Time in Patent Office: 1,216 Days
• Field of Search: 429/231.95, 429/322, 429/211, 204/192.15, 216/13
• US Class Current: 429/322
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0562 Solid materials
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 2300/0068 inorganic
• CPC Class Codes: H01M 6/18 with solid electrolyte
• CPC Class Codes: H01M 6/186 Only oxysalts-containing solid electrolytes
• CPC Class Codes: H01M 6/187 Solid electrolyte characterised by the form
• CPC Class Codes: H01M 6/40 Printed batteries , e.g. thin film batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The microbattery is formed by a stack of solid thin layers on a substrate which, starting from the substrate, successively comprises a first electrode, a solid electrolyte and a second electrode/current collector assembly. A first surface and a second surface of the electrolyte are respectively in contact with a main surface of the first electrode and a main surface of the second electrode/current collector assembly. The dimensions of the main surface of the first electrode are smaller than the dimensions of the main surface of said assembly, and the dimensions of the first surface of the solid electrolyte are smaller than the dimensions of the second surface of the solid electrolyte. The solid electrolyte is furthermore not in contact with the substrate.

Claims

1. A lithium microbattery comprising a stack of solid thin layers on a substrate, said stack successively comprising, starting from the substrate, a first electrode, a solid electrolyte, and a second electrode/current collector assembly formed by at least one thin layer,

wherein:

a first surface and a second surface of the electrolyte is in contact respectively with a main surface of the first electrode and a main surface of the second electrode/current collector assembly, said main surfaces facing one another;

dimensions of the main surface of the first electrode are smaller than dimensions of the main surface of said assembly;

dimensions of the first surface of the solid electrolyte are smaller than dimensions of the second surface of the solid electrolyte;

the solid electrolyte is not in contact with the substrate; and

the solid electrolyte has a trapezoid shape, in cross-section, with a small base and a large base respectively constituting the first surface and the second surface of the electrolyte.

2. The microbattery according to claim 1, wherein:

the first electrode comprises at least one lateral surface, and

no lateral surface is completely covered by the solid electrolyte.

3. The microbattery according to claim 1, wherein:

the dimensions of the first surface of the electrolyte are substantially equal to the dimensions of the main surface of the first electrode, and

the dimensions of the second surface of the electrolyte are substantially equal to the dimensions of the main surface of the second electrode/current collector assembly.

4. The microbattery according to claim 1, wherein a difference between a diameter, width, or length of the first surface of the electrolyte and a corresponding diameter, width, or length of the second surface of the electrolyte is between 0.2 μ

m and 2000 μ

m.

5. The microbattery according to claim 1, wherein the solid electrolyte is a lithium-base compound.

6. The microbattery according to claim 1, wherein the second electrode/current collector assembly comprises:

a thin layer constituting the second electrode; and

a thin layer constituting the current collector.

7. The microbattery according to claim 6, wherein the second electrode comprises one or more materials chosen from transition metals and alloys, metalloids and their alloys, and lithium intercalation and insertion materials.

8. The microbattery according to claim 1, wherein the second electrode/current collector assembly consists of a single thin layer.

9. The microbattery according to claim 6, wherein the current collector or the second electrode/current collector assembly consists of a single thin layer made from metal or from metal alloy.

10. A fabrication method of a lithium microbattery according to claim 1, successively comprising:

full wafer deposition, on the substrate, of the first electrode and then of the solid electrolyte and of at least one thin layer to form the second electrode/current collector assembly;

selective etching of said assembly; and

selective etching, by a wet process, of the solid electrolyte and of the first electrode, said wet etching comprising at least one aqueous etching solution to pattern the solid electrolyte in the trapezoid shape, in cross-section, with the small base and the large base respectively contacting the first and the second electrodes.

11. The method according to claim 10, wherein the solid electrolyte and the first electrode are etched simultaneously by the wet process.

12. The method according to claim 10, wherein:

the second electrode/current collector assembly comprises a thin layer constituting the second electrode and a thin layer constituting the current collector, and

said thin layers are etched simultaneously through at least one mask.

13. The method according to claim 10, wherein:

the solid electrolyte is a lithium-base compound; and

the aqueous etching solution is an alkaline solution.

14. The method according to claim 10, wherein selective etching of the second electrode/current collector assembly is a dry process etching.

15. A lithium microbattery comprising a stack of solid thin layers on a substrate, said stack successively comprising, starting from the substrate, a first electrode, a solid electrolyte, and a second electrode/current collector assembly formed by at least one thin layer,

wherein:

a first surface and a second surface of the electrolyte is in contact respectively with a main surface of the first electrode and a main surface of the second electrode/current collector assembly, said main surfaces facing one another;

dimensions of the main surface of the first electrode are smaller than dimensions of the main surface of said assembly;

dimensions of the first surface of the solid electrolyte are smaller than dimensions of the second surface of the solid electrolyte;

the dimensions of the first surface of the electrolyte are substantially equal to the dimensions of the main surface of the first electrode;

the dimensions of the second surface of the electrolyte are substantially equal to the dimensions of the main surface of the second electrode/current collector assembly;

the dimensions of the first surface of the electrolyte are smaller than the dimensions of the second surface of the electrolyte; and

the solid electrolyte is not in contact with the substrate.

16. The microbattery according to claim 15, wherein:

the first electrode comprises at least one lateral surface, and

no lateral surface is completely covered by the solid electrolyte.

17. The microbattery according to claim 15, wherein the solid electrolyte has a trapezoid shape, in cross-section, with a small base and a large base respectively constituting the first surface and the second surface of the electrolyte.

18. The microbattery according to claim 15, wherein a difference between a diameter, width, or length of the first surface of the electrolyte and a corresponding diameter, width, or length of the second surface of the electrolyte is between 0.2 μ

m and 2000 μ

m.

19. The microbattery according to claim 15, wherein the solid electrolyte is a lithium-base compound.

20. The microbattery according to claim 15, wherein the second electrode/current collector assembly comprises:

a thin layer constituting the second electrode; and

a thin layer constituting the current collector.

21. The microbattery according to claim 20, wherein the second electrode comprises one or more materials chosen from transition metals and alloys, metalloids and their alloys, and lithium intercalation and insertion materials.

22. The microbattery according to claim 15, wherein the second electrode/current collector assembly consists of a single thin layer.

23. The microbattery according to claim 20, wherein the current collector or the second electrode/current collector assembly consists of a single thin layer made from metal or from metal alloy.