Electrolytes for lithium-sulfur electrochemical cells
View Patent ↗Disclosed is an electrolyte for an electrochemical cell wherein the electrolyte includes a solvent mixture comprising a dioxolane and one or more of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and/or 1,3-dialkoxyalkanes of 5 or 6 carbon atoms. Also disclosed are cells and batteries including the electrolyte. An electrochemical cell including the electrolyte preferably has an anode that includes lithium and a cathode including an electroactive sulfur-containing material.
1. An electrochemical cell comprising:
(a) an anode comprising lithium;
(b) a cathode comprising an electroactive sulfur-containing material; and
(c) a liquid nonaqueous electrolyte, wherein the electrolyte comprises:
(i) one or more lithium salts; and
(ii) a solvent mixture comprising 10 to 90% by weight of a dioxolane and 10 to 90% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms.
2. The cell of claim 1 wherein the solvent mixture comprises 30 to 80% by weight of a dioxolane and 20 to 70% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms.
3. The cell of claim 1 wherein the solvent mixture comprises 50 to 75% by weight of a dioxolane and 25 to 50% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms.
4. The cell of claim 1 wherein the one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms are selected from one or more of the group consisting of 1-ethoxy-2-methoxyethane, 1-methoxy-2-propoxyethane, 1,2-dimethoxypropane, 1-ethoxy-2-methoxypropane, 2-ethoxy-1-methoxypropane, and 1,3-dimethoxypropane.
5. The cell of claim 4 wherein the one or more of the group consisting of 1,2-dialkoxyalkanes and 1,3-dialkoxyalkanes is 1-ethoxy-2-methoxyethane.
6. The cell of claim 1 wherein the dioxolane is selected from one or more of the group consisting of 1,3-dioxolane and 4-methyl-1,3-dioxolane.
7. The cell of claim 6 wherein the dioxolane is 1,3-dioxolane.
8. The cell of claim 1 wherein the electroactive sulfur-containing material comprises elemental sulfur.
9. The cell of claim 1 wherein the electrolyte solvent mixture further comprises an additive selected from one or more of the group consisting of furan, 2-methylfuran, 2,5-dimethylfuran, 2-methylthiophene, 2,5-dimethylthiophene, and 1-methylpyrrole.
10. The cell of claim 9 wherein the additive comprises from 2 to 15% by weight of the electrolyte solvent.
11. The cell of claim 9 wherein the additive comprises from 3 to 10% by weight of the electrolyte solvent.
12. The cell of claim 1 wherein the one or more lithium salts are selected from one or more of the group consisting of LiBr, LiI, LiSO 3 CF 3 , LiN(SO 2 CF 3 ) 2 , and LiC(SO 2 CF 3 ) 3 .
13. The cell of claim 1 wherein the anode comprises lithium metal.
14. A battery comprising a casing and one or more cells of claim 1 .
15. An electrolyte of an electrochemical cell wherein the electrolyte comprises:
(a) one or more lithium salts; and
(b) a solvent mixture comprising 10 to 90% by weight of a dioxolane and 10 to 90% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms.
16. The electrolyte of claim 15 wherein the solvent mixture comprises 50 to 75% by weight of a dioxolane and 25 to 50% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms.
17. The electrolyte of claim 15 wherein the solvent mixture further comprises an additive selected from the group consisting of furan, 2-methylfuran, 2,5-dimethylfuran, 2-methylthiophene, 2,5-dimethylthiophene, and 1-methylpyrrole.
18. The electrolyte of claim 17 wherein the additive comprises from 3 to 10% by weight of the electrolyte solvent.
19. The electrolyte of claim 15 wherein the one or more lithium salts are selected from one or more of the group consisting of LiBr, LiI, LiSO 3 CF 3 , LiN(SO 2 CF 3 ) 2 , and LiC(SO 2 CF 3 ) 3 .
20. The cell of claim 15 wherein the electroactive sulfur-containing material comprises elemental sulfur.
21. 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 lithium salts; and
(ii) a solvent mixture comprising 10 to 90% by weight of a dioxolane and 10 to 90% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms; and wherein the cell exhibits a utilization of the electroactive sulfur containing material of at least 35% over at least 200 cycles at a discharge rate of about 0.4 mA/cm 2 .
22. The cell of claim 21 that exhibits a utilization of the electroactive sulfur containing material of at least 35% over at least 250 cycles at a discharge rate of about 0.4 mA/cm 2 .
23. The cell of claim 21 wherein the solvent mixture comprises 50 to 75% by weight of a dioxolane and 25 to 50% by weight of one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes of 5 or 6 carbon atoms.
24. The cell of claim 21 wherein the one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes are selected from one or more of the group consisting of 1-ethoxy-2-methoxyethane, 1-methoxy-2-propoxyethane, 1,2-dimethoxypropane, 1-ethoxy-2-methoxypropane, 2-ethoxy-1-methoxypropane, and 1,3-dimethoxypropane.
25. The cell of claim 21 wherein the one or more of the group consisting of 1,2-dialkoxyalkanes of 5 or 6 carbon atoms and 1,3-dialkoxyalkanes is 1-ethoxy-2-methoxyethane.
26. The cell of claim 21 wherein the dioxolane is selected from one or more of the group consisting of 1,3-dioxolane and 4-methyl-1,3-dioxolane.
27. The cell of claim 21 wherein the solvent mixture further comprises an additive selected from one or more of the group consisting of furan, 2-methylfuran, 2,5-dimethylfuran, 2-methylthiophene, 2,5-dimethylthiophene, and 1-methylpyrrole.
28. The cell of claim 27 wherein the additive comprises from 3 to 10% by weight of the electrolyte solvent.
29. A battery comprising a casing and one or more cells of claim 21 .
30. The cell of claim 21 wherein the electroactive sulfur-containing material comprises elemental sulfur.