Low temperature electrochemical cells
View Patent ↗Disclosed is an electrochemical cell comprising a lithium anode and a sulfur-containing cathode and a non-aqueous electrolyte solvent. In the fully charged state of the cell the concentration of lithium ions is preferably less than 0.3 M. The cell delivers high discharge capacity at discharge rates, for example, C/5, over temperatures ranges of from +25° C. to −20° C. Also disclosed is a battery including an electrochemical cell according to the invention and a device that utilizes such a battery to derive power.
1. An electrochemical cell comprising;
(a) an anode comprising lithium;
(b) a cathode comprising an electroactive sulfur-containing material; and
(c) a non-aqueous electrolyte interposed between the anode and the cathode, the electrolyte comprising:
(i) one or more nonaqueous oxygen-containing solvents selected from the group consisting of acyclic ethers, cyclic ethers, polyethers, and sulfones; and
(ii) one or more lithium salts, wherein at least one of the one or more lithium salts is selected from the group consisting of LiBr, LiI, LiSCN, LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , and LiC(CF 3 SO 2 ) 3 ;
wherein, in the fully charged state of the cell, the concentration of the one or more lithium sats is less than 0.3 M and wherein the cell delivers at a discharge rate of from C/5 to 5 C, greater than 35% of the theoretical discharge capacity of the electroactive sulfur-containing material at temperatures between +25 ° C. to −20 ° C.
2. The cell of claim 1 , wherein the concentration of the one or more lithium salts is less than 0.15 M.
3. The cell of claim 1 , wherein the concentration of the one or more lithium salts is less than 0.05 M.
4. The cell of claim 1 , wherein the concentration of the one or more lithium salts is less than 0.01 M.
5. The cell of claim 4 , wherein the cell delivers 40% of the theoretical discharge capacity of the electroactive sulfur-containing material for more than 40 charge-discharge cycles at a C/5 rate when the cell is discharged to 0.0 V.
6. The cell of claim 4 , wherein the cell delivers 40% of the theoretical discharge capacity of the electroactive sulfur-containing material for more than 40 charge-discharge cycles at a C/5 rate when the cell is discharged to 0.0 V.
7. The cell of claim 1 , wherein the acyclic ether is selected from one or more of the group consisting of diethyl ether, dipropyl ether, dibutyl ether, methyl t-butyl ether, dimethoxymethane, trimethoxymethane, dimethoxyethane, diethoxxyethane, and 1,3-dimethoxyproane.
8. 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-dioxane, 1,3-dioxane, and 1,4-dioxane.
9. 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.
10. 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.
11. The cell of claim 1 , wherein the one or more non-aqueous solvents comprises at east 80% by weight of dioxolane.
12. The cell of claim 1 , wherein the one or more lithium salts is selected from the group consisting of LiSCN, LiCF 3 SO 3 , and LiN(CF 3 SO 2 ) 2.
13. The cell of claim 1 , wherein the electroactive sulfur-containing material comprises greater than 75% by weight of sulfur.
14. The cell of claim 1 , wherein the electroactive sulfur-containing material comprises elemental sulfur.
15. The cell of claim 1 , wherein the anode comprises lithium metal.
16. The cell of claim 1 that further includes a separator disposed between the anode and the cathode.
17. A battery comprising a casing and one or more cells of claim 1 .
18. A device that utilizes a battery to derive power, the battery comprising a casing and one or more cells of claim 1 .
19. The device of claim 18 that is a cellular telephone.
20. The cell of claim 1 , wherein the cell after four discharge-charge cycles delivers at a C/5 rate greater 40% of the theoretical discharge capacity of the electroactive sulfur-containing material.
21. The cell of claim 1 , wherein the electroactive sulfur-containing material comprises elemental sulfur.
22. The cell of claim 1 , wherein the anode comprises lithium metal.
23. An electrochemical cell comprising;
(a) an anode comprising lithium;
(b) a cathode comprising an electroactive sulfur-containing material; and
(c) a non-aqueous electrolyte interposed between the anode and the cathode, the electrolyte comprising one or more nonaqueous oxygen-containing solvents selected from the group consisting of acyclic ethers, cyclic ethers, polyethers, and sulfones; and wherein, in the fully charged state of the cell, the concentration of lithium salts is essentially zero and wherein the cell delivers at a discharge rate of from C/5 to 5C, greater than 35% of the theoretical discharge capacity of the electroactive sulfur-containing material at temperatures between +25° C. to −20° C.
24. The cell of claim 1 , wherein the cell after four discharge-charge cycles delivers at a C/5 rate greater 40% of the theoretical discharge capacity of the electroactive sulfur-containing material.
25. The cell of claim 1 , wherein the cell after four discharge-charge cycles delivers at a C/5 rate greater than 35% of the theoretical discharge capacity of the electroactive sulfur-containing material at temperatures between +25° C. to −10° C.
26. The cell of claim 1 , wherein the cell delivers at each discharge cycle greater than 40% of the theoretical discharge capacity of the electroactive sulfur-containing material for more than 10 charge-discharge cycles at a C/5 rate at −10° C.
27. The cell of claim 1 , wherein the cell delivers at each discharge cycle greater than 40% of the theoretical discharge capacity of the electroactive sulfur-containing material for more than 40 charge-discharge cycles at a C/5 rate at −10° C. dimethoxymethane, trimethoxymethane, dimethoxyethane, diethoxyethane, and 1,3-dimethoxypropane.
28. The cell of claim 23 , wherein the acyclic ether is selected from one or more of the group consisting of diethyl ether, dipropyl ether, dibutyl ether, methyl t-butyl ether, dimethoxymethane, trimethoxymethane, dimethoxyethane, diethoxyethane, and 1,3-dimethoxypropane.
29. The cell of claim 5 , 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.
30. The cell of claim 23 , 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.
31. The cell of claim 23 , wherein the sulfone is selected from one or more of the group consisting of sulfolane, 3-methyl sulfolane, and 3-sulfolene.
32. The cell of claim 23 , wherein the one or more non-aqueous solvents comprises at east 80% by weight of dioxolane.