Synthesis of gamma monoclinic sulfur and sulfur batteries containing monoclinic sulfur
The present invention relates to a novel cathode employing a monoclinic sulfur phase that enables a single plateau lithium-sulfur reaction in, for example, a carbonate electrolyte system. The cathode is applicable to a variety of other types of anodes. Also disclosed are an electrode of a cell or battery and a battery including the cathode.
1. A cathode comprising a monoclinic phase sulfur that is stable at a temperature below 80° C. located on a substrate, wherein the monoclinic phase sulfur comprises monoclinic gamma phase sulfur, wherein
(a) the monoclinic gamma phase sulfur comprises intensity peaks in its x-ray diffraction spectrum that match relative intensities as shown in FIG. 4 A of the specification.
2. The cathode of claim 1 , wherein the cathode includes a current collector.
3. The cathode of claim 1 , wherein the cathode has an initial discharge capacity in a range of from about 300 mAh/g to about 2500 mAh/g, based on a total weight of sulfur in the cathode.
4. The cathode of claim 1 , wherein the cathode has a loading of the monoclinic phase sulfur in a range of at least 0.05 mg/cm 2 .
5. A sulfur cell comprising the cathode of claim 1 , an anode, and an electrolyte.
6. The sulfur cell of claim 5 , wherein the electrolyte is a carbonate electrolyte.
7. The sulfur cell of claim 6 , wherein the carbonate electrolyte is selected from the group consisting of ethylene carbonate, dimethylcarbonate, methylethyl carbonate, diethylcarbonate, propylene carbonate, vinylene carbonate, allyl ethyl carbonate, and mixtures thereof.
8. The sulfur cell of claim 6 , wherein the carbonate electrolyte is selected from the group consisting of ethylene carbonate, diethyl carbonate, propylene carbonate and mixtures thereof.
9. The sulfur cell of claim 5 , wherein the anode is an ion reservoir including an active material selected from the group consisting of alkali metals, alkaline metals, transition metals, graphite, alloys, and composites.
10. The sulfur cell of claim 5 , wherein the anode includes an active material selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, zinc, copper, titanium, nickel, cobalt, iron, or aluminum.
11. The sulfur cell of claim 5 , wherein the cell is selected from a lithium-sulfur cell, a sodium-sulfur cell, a potassium-sulfur cell, a magnesium-sulfur cell, and a calcium-sulfur cell.
12. The sulfur cell of claim 5 , wherein the cell exhibits a single plateau discharge curve with a discharge capacity of from 300 mAh/g to about 1700 mAh/g, all based on a total weight of the sulfur in the cathode, or the cell exhibits a single plateau discharge curve with a discharge capacity of from about 300 mAh/g to about 3000 mAh/g after a first cycle at a C/10 rate, all based on a total weight of the sulfur in the cathode.
13. The sulfur cell of claim 5 , wherein the cell has a discharge capacity of from about 100 mAh/g to about 1500 mAh/g, after 1300 cycles at a C/2 rate, all based on a total weight of the sulfur in the cathode.
14. The sulfur cell of claim 5 , wherein the cell is selected from a lithium-sulfur cell, a sodium-sulfur cell, and a potassium-sulfur cell.
15. The sulfur cell of claim 5 , wherein the cell is a rechargeable cell.
16. The sulfur cell of claim 5 , wherein the cell comprises a current collector.
17. A sulfur battery comprising a plurality of the sulfur cells of claim 5 .
18. The sulfur battery of claim 17 , further comprising a porous separator, wherein the separator is provided between an anodic section and a cathodic section of the battery.
19. The sulfur battery of claim 18 , wherein the separator comprises a material selected from the group consisting of a porous polypropylene membrane, cotton, nylon, polyesters, glass fiber, polyethylene, poly(tetrafluoroethylene, polyvinyl chloride, anodic aluminum oxide and rubber.
20. The cathode of claim 1 , wherein the substrate is conductive.
21. The cathode of claim 1 , wherein the substrate is non-conductive.
22. The cathode of claim 1 , wherein the substrate comprises carbon nanofibers.
23. The cathode of claim 22 , wherein the carbon nanofibers are free-standing carbon nanofibers.
24. The cathode of claim 1 , wherein the cathode has a loading of the monoclinic phase sulfur in a range of at least 0.5 mg/cm 2 .
25. A cathode comprising a monoclinic phase sulfur that is stable at a temperature below 80° C. located on a substrate, wherein the monoclinic phase sulfur has an x-ray diffraction spectrum comprising the following peaks:
Reflection - (hkl)
2 theta
Intensity
020
13.58
532.31
030
20.44
121.66
040
27.37
790.48
050
34.40
0
060
41.56
89.12
070
48.91
87.7
080
56.47
93.94
090
54.10
115.1
26. The cathode of claim 25 , wherein at least a portion of the monoclinic gamma phase sulfur is located on a surface of the substrate and is not confined.