Electrolytes for lithium sulfur cells

• US 20050147891A1
• Filed: 01/06/2004
• Published: 07/07/2005
• Est. Priority Date: 01/06/2004
• Status: Active Grant

• Current Assignee: Sion Power Corporation
• Original Assignee: Moltech Corporation
• Inventors: Mikhaylik, Yuriy V.
• Granted Patent: US 7,354,680 B2
• Time in Patent Office: Days
• US Class Current: 429/326
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/40 Alloys based on alkali metals
• CPC Class Codes: H01M 6/164 by the solvent
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed is an additive for an electrochemical cell wherein the additive includes an N—O bond. The additive is most preferably included in a nonaqueous electrolyte of the cell. Also disclosed are cells and batteries including the additive, and methods of charging the batteries and cells. An electrochemical cell including the additive preferably has an anode that includes lithium and a cathode including an electroactive sulfur-containing material.

Claims

1. An electrochemical cell comprising:

(a) a cathode comprising an electroactive sulfur-containing material;

(b) an anode comprising lithium; and

(c) a nonaqueous electrolyte, wherein the electrolyte comprises;

(i) one or more nonaqueous solvents selected from the group consisting of acyclic ethers, cyclic ethers, polyethers, and sulfones;

(ii) one or more lithium salts; and

(iii) one or more N—

O additives.

2. The cell of claim 1 wherein the one or more N—

O additives is selected from one or more of the group consisting of inorganic nitrates, organic nitrates, inorganic nitrites, and organic nitro compounds.

3. The cell of claim 2 wherein the inorganic nitrate is selected from one or more of the group consisting of lithium nitrate, potassium nitrate, cesium nitrate, barium nitrate, and ammonium nitrate.

4. The cell of claim 2 wherein the inorganic nitrite is selected from one or more of the group consisting of lithium nitrite, potassium nitrite, cesium nitrite, and ammonium nitrite.

5. The cell of claim 2 wherein the organic nitro compound is selected from one or more of the group consisting of nitromethane, nitropropane, nitrobenzene, dinitrobenzene, nitrotoluene, dinitrotoluene, and nitropyridine.

6. The cell of claim 1 wherein the one or more lithium salts is selected from one or more of the group consisting of LiSCN, LiCF₃SO₃, and LiN(CF₃SO₂)₂.

7. The cell of claim 1 wherein the one or more lithium salts consist of LiSCN and LiN(CF₃SO₂)₂ and the N—

O additive comprises lithium nitrate.

8. The cell of claim 1 wherein the concentration of the one or more N—

O additives in the electrolyte is from about 0.02 m to 2.0 m.

9. The cell of claim 1 wherein the concentration of the one or more N—

O additives in the electrolyte is from about 0.1 m to 1.5 m.

10. The cell of claim 1 wherein the concentration of the one or more N—

O additives in the electrolyte is from about 0.2 m to 1.0 m.

11. The cell of claim 1 wherein the concentration of the one or more lithium salts in the electrolyte is from about 0.2 m to about 2.0 m.

12. The cell of claim 1 wherein the acyclic ether is selected from one or more of the group consisting of dimethoxymethane, trimethoxymethane, dimethoxyethane, diethoxyethane, and 1,3-dimethoxypropane.

13. The cell of claim 1 wherein the cyclic ether is selected from one or more of the group consisting of tetrahydrofuran, 2-methyl tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,3-dioxane, and 1,4-dioxane.

14. The cell of claim 1 wherein the polyether is selected from one or more of the group consisting of diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether.

15. The cell of claim 1 wherein the sulfone is selected from one or more of the group consisting of sulfolane, 3-methyl sulfolane, and 3-sulfolene.

16. The cell of claim 1 wherein the electroactive sulfur-containing material comprises greater than 75% by weight of sulfur.

17. The cell of claim 1 wherein the electroactive sulfur-containing material comprises elemental sulfur.

18. The cell of claim 1 wherein the anode comprises lithium metal.

19. The cell of claim 1 that further includes a separator disposed between the anode and the cathode.

20. A battery comprising a casing and one or more cells of claim 1.

21. The cell of claim 1 wherein the one or more N—

O additives is lithium nitrate.

22. The cell of claim 1 wherein the nonaqueous solvent comprises dioxolane.

23. The cell of claim 1 wherein the one or more solvents consists of dimethoxyethane and dioxolane.

24. The cell of claim 19 wherein the one or more N—

O additives was included as part of the separator and was introduced into the electrolyte after the electrolyte came into contact with the separator.

25. The cell of claim 1 wherein the one or more N—

O additives was included as part of the cathode and was introduced into the electrolyte after the electrolyte came into contact with the cathode.

26. An electrochemical cell comprising:

(a) a cathode comprising an electroactive sulfur-containing material;

(b) an anode comprising lithium; and

(c) a nonaqueous electrolyte, wherein the electrolyte comprises;

(i) one or more nonaqueous solvents selected from the group consisting of acyclic ethers, cyclic ethers, polyethers, and sulfones; and

(ii) one or more N—

O additives.

27. The cell of claim 26 wherein the one or more N—

O additives is selected from one or more of the group consisting of inorganic nitrates, organic nitrates, and inorganic nitrites.

28. The cell of claim 27 wherein the inorganic nitrate is selected from one or more of the group consisting of lithium nitrate, potassium nitrate, cesium nitrate, barium nitrate, and ammonium nitrate.

29. The cell of claim 27 wherein the inorganic nitrite is selected from one or more of the group consisting of lithium nitrite, potassium nitrite, cesium nitrite, and ammonium nitrite.

30. The cell of claim 26 wherein the concentration of the one or more N—

O additives in the electrolyte is from about 0.2 m to 2.0 m.

31. The cell of claim 26 wherein the electrolyte further comprises one or more lithium salts selected from one or more of the group consisting of LiSCN, LiCF₃SO₃, and LiN(CF₃SO₂)₂.

32. The cell of claim 26 that further includes a separator disposed between the anode and the cathode.

33. The cell of claim 32 wherein the one or more N—

O additives was included as part of the separator and introduced into the electrolyte after the electrolyte came into contact with the separator.

34. The cell of claim 26 wherein the one or more N—

O additives was included as part of the cathode and introduced into the electrolyte after the electrolyte came into contact with the cathode.

35. A battery comprising a casing and one or more cells of claim 26.