Electrolytes for lithium sulfur cells
View Patent ↗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.
1. An electrochemical cell compnsing:
(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, wherein the one or more N—O additives comprises an inorganic nitrite selected from one or more of the group consisting of lithium nitrite, potassium nitrite, cesium nitrite, and ammonium nitrite.
2. The cell of claim 1 wherein the one or more N—O additives further comprise one or more of the group consisting of inorganic nitrates, organic nitrates, organic nitrites, and organic nitro compounds.
3. 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, nitropyridine, dinitropyridine, nitrobutanes, and dialkyl imiazolium.
4. The cell of claim 1 wherein the one or more lithium salts is selected from one or more of the group consisting of LiSCN, LiCF 3 SO 3 , and LiN(CF 3 SO 2 ) 2 .
5. 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.
6. 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.
7. 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.
8. 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.
9. 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, 1,4-dioxane, and trioxane.
10. The cell of claim 1 wherein the electroactive sulfur-containing material comprises greater than 75% by weight of sulfur.
11. The cell of claim 1 wherein the electroactive sulfur-containing material comprises elemental sulfur.
12. The cell of claim 1 wherein the anode comprises lithium metal.
13. The cell of claim 1 that further includes a separator disposed between the anode and the cathode.
14. The cell of claim 13 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.
15. A battery comprising a casing and one or more cells of claim 1 .
16. The cell of claim 1 wherein the nonaqueous solvent comprises dioxolane.
17. The cell of claim 16 wherein the nonaqueous solvent comprises greater than 40% by weight dioxolane.
18. The cell of claim 1 wherein the one or more solvents consists of dimethoxyethane and dioxolane.
19. 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.
20. The cell of claim 1 wherein the one or more lithium salts are selected from one or more of the group consisting of LiSCN, LiBr, LiI, LiClO 4 , LiAsF 6 , LiSO 3 CF 3 , LiSO 3 CH 3 , LiBF 4 , LiB(Ph) 4 , LiPF 6 , LiC(SO 2 CF 3 ) 3 , and LiN(SO 2 CF 3 ) 2 .
21. The cell of claim 1 wherein the nonaqueous electrolyte comprises two or more solvents selected from acyclic ethers, glymes and cyclic ethers.
22. The cell of claim 21 wherein one of the two or more non aqueous solvents is dioxolane.
23. The cell of claim 1 wherein the one or more nonaqueous solvents consist of:
1,3-dioxolane and dimethoxyethane; or
1,3-dioxolane and diethyleneglycol dimethyl ether; or
1,3-dioxolane and triethyleneglycol dimethyl ether; or
1,3-dioxolane and sulfolane.
24. The cell of claim 23 wherein the electrolyte comprises a binary mixture and the weight ratio of the components of the binary mixture are from about 5 to 95 to 95 to 5.
25. The cell of claim 23 wherein the non aqueous solvent comprises greater than 40% by weight dioxolane.
26. An electrochemical cell comprising:
(a) a cathode comprising an electroactive sulfur-containing material;
(b) an anode comprising lithium; and
(c) a nonagueous electrolyte, wherein the electrolyte comprises:
(i) one or more nonagueous 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;
wherein the one or more lithium salts consist of LiSCN and LiN(CF 3 SO 2 ) 2 and the N—O additive comprises lithium nitrate.
27. An electrochemical cell comprising:
(a) a cathode comprising an electroactive sulfur-containing material;
(b) an anode comprising lithium; and
(c) a nonagueous electrolyte, wherein the electrolyte comprises;
(i) one or more nonagueous 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, wherein the one or more N—O additives is lithium nitrate.
28. The cell of claim 27 wherein the concentration of the one or more N—O additives in the electrolyte is from about 0.02 m to 2.0 m.
29. The cell of claim 27 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, 1,4-dioxane, and trioxane.
30. The cell of claim 27 wherein the electroactive sulfur-containing material comprises elemental sulfur.
31. The cell of claim 27 wherein the anode comprises lithium metal.
32. The cell of claim 27 wherein the nonaqueous solvent comprises dioxolane.
33. The cell of claim 32 wherein the nonaqueous solvent comprises greater than 40% by weight dioxolane.
34. The cell of claim 27 wherein the nonaqueous electrolyte comprises two or more solvents selected from acyclic ethers, glymes and cyclic ethers.
35. The cell of claim 34 wherein one of the two or more non aqueous solvents is dioxolane.
36. The cell of claim 27 wherein the one or more nonaqueous solvents consist of:
1,3-dioxolane and dimethoxyethane; or
1,3-dioxolane and diethyleneglycol dimethyl ether; or
1,3-dioxolane and triethyleneglycol dimethyl ether; or
1,3-dioxolane and sulfolane.
37. The cell of claim 36 wherein the electrolyte comprises a binary mixture and the weight ratio of the components of the binary mixture are from about 5 to 95 to 95 to 5.
38. The cell of claim 37 wherein the non aqueous solvent comprises greater than 40% by weight dioxolane.
39. An electrochemical cell comprising:
(a) a cathode comprising an electroactive sulfur-containing material;
(b) an anode comprising lithium; and
(c) a nonagueous electrolyte, wherein the electrolyte comprises:
(i) one or more nonagueous solvents selected from the group consisting of acyclic ethers, cyclic ethers, polyethers, and sulfones; and
(ii) one or more N—O additives, wherein the one or more N—O additives comprises an inorganic nitrite selected from one or more of the group consisting of lithium nitrite, potassium nitrite, cesium nitrite, and ammonium nitrite.
40. The cell of claim 39 wherein the one or more N—O additives further comprises one or more of the group consisting of inorganic nitrates, and organic nitrates.
41. The cell of claim 39 wherein the concentration of the one or more N—O additives in the electrolyte is from about 0.2 m to 2.0 m.
42. The cell of claim 39 that further includes a separator disposed between the anode and the cathode.
43. The cell of claim 42 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.
44. The cell of claim 39 wherein the one or more N—O additives was included as part of the cathoded and introduced into the electrolyte after the electrolyte came into contact with the cathode.
45. A battery comprising a casing and one or more cells of claim 39 .