SOLID SOLUTION LITHIUM ALLOY CERMET ANODES

• US 20100181528A1
• Filed: 06/05/2008
• Published: 07/22/2010
• Est. Priority Date: 06/19/2007
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Richardson, Thomas J.
• Granted Patent: US 8,480,922 B2
• Time in Patent Office: Days
• US Class Current: 252/182.100
• CPC Class Codes: C01B 21/06 Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boronazides C01B21/08
• CPC Class Codes: C01B 21/0602 with two or more other elements chosen from metals, silicon or boron
• CPC Class Codes: C01B 21/0612 with alkaline-earth metals, beryllium or magnesium
• CPC Class Codes: C01B 21/0635 with germanium, tin or lead
• CPC Class Codes: C01B 21/0637 with metals not specified in groups C01B21/0607 - C01B21/0635, other than aluminium, titanium, zirconium or hafnium
• CPC Class Codes: C01B 21/068 with silicon
• CPC Class Codes: C01B 21/072 with aluminium
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/382 Lithium H01M4/405 takes precedence
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/387 Tin or alloys based on tin
• CPC Class Codes: H01M 4/405 Alloys based on lithium
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A metal-ceramic composite (“cermet”) has been produced by a chemical reaction between a lithium compound and another metal. The cermet has advantageous physical properties, high surface area relative to lithium metal or its alloys, and is easily formed into a desired shape. An example is the formation of a lithium-magnesium nitride ceiniet by reaction of lithium nitride with magnesium. The reaction results in magnesium nitride grains coated with a layer of lithium. The nitride is inert when used in a battery. It supports the metal in a high surface area form, while stabilizing the electrode with respect to dendrite formation. By using an excess of magnesium metal in the reaction process, a cermet of magnesium nitride is produced, coated with a lithium-magnesium alloy of any desired composition. This alloy inhibits dendrite formation by causing lithium deposited on its surface to diffuse under a chemical potential into the bulk of the alloy.

Claims

1. A method for forming a lithium-metal composition, comprising:

providing Li₃N powder;

mixing a metal (M) powder into the Li₃N powder;

heating to cause a reaction that forms a Li-metal composition.

2. The method of claim 1 wherein the Li-metal composition is a Li-metal alloy.

3. The method of claim 1 wherein the Li-metal composition is an intermetallic compound containing lithium.

4. The method of claim 1 wherein the metal is selected from the group consisting of magnesium, aluminum, tin, silicon, antimony, germanium, gallium, indium, and their alloys with one another or with lithium.

5. The method of claim 1 wherein the reaction also forms a metal nitride.

6. The method of claim 2 wherein the alloy phase is stable over a composition range between about 30% and 100% Li.

7. The method of claim 3 wherein the reaction product of the metal and Li₃N is a free flowing powder.

15. The method of claim 1 wherein a second metal powder is mixed with the Li₃N powder and the first metal powder prior to heating.

16. The method of claim 15 wherein the first metal powder is magnesium and the second metal powder is tin.

17. The method of claim 15 wherein the first metal powder is magnesium and the second metal powder is silicon.

18. An electrode suitable for use in a lithium ion battery comprising as the active material the nitrogen free lithium-metal composition formed by the reaction process of claim 1.

19. The electrode of claim 18 wherein the electrode is an anode.

20. The lithium metal composition produced by the method of claim 4 wherein the metal nitride is silicon nitride and the lithium-metal composition is lithium-silicon.

21. The lithium metal composition produced by the method of claim 4 wherein the metal nitride is aluminum nitride and the lithium-metal composition is lithium-aluminum.

22. The lithium metal composition produced by the method of claim 4 wherein the metal nitride is magnesium nitride and the lithium-metal composition is lithium-magnesium.

8. A cermet composition, comprising grains of a metal nitride coated with lithium-metal composition.

9. The cermet composition of claim 8 wherein the composition is a free flowing powder.

10. The cermet composition of claim 8 wherein the lithium-metal composition is selected from the group consisting of lithium magnesium, lithium aluminum, lithium tin, lithium silicon, lithium antimony, lithium germanium, lithium gallium, lithium indium, and combinations thereof.

11. The cermet composition of claim 8 wherein the metal nitride is selected from the group consisting of magnesium nitride, aluminum nitride, tin nitride, silicon nitride, antimony nitride, germanium nitride, gallium nitride, indium nitride, and combinations thereof.

12. The cermet composition of claim 8 wherein the metal nitride is magnesium nitride and the lithium-metal composition is lithium-magnesium.

13. The cermet composition of claim 10, further comprising at least one additional metal.

14. The cermet composition of claim 13 wherein the lithium metal is combined with tin and silicon.