期刊
NANO LETTERS
卷 13, 期 12, 页码 5891-5899出版社
AMER CHEMICAL SOC
DOI: 10.1021/nl402793z
关键词
Energy storage; lithium batteries; sulfur; graphene oxides; cathodes
类别
资金
- University of California, Office of The President, UC Proof of Concept [12PC247581]
- Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy [DE-ACO20-5CH11231]
Lithium/sulfur (Li/S) cells are receiving significant attention as an alternative power source for zero-emission vehicles and advanced electronic devices due to the very high theoretical specific capacity (1675 mA.h/g) of the sulfur cathode. However, the poor cycle life and rate capability have remained a grand challenge, preventing the practical application of this attractive technology. Here, we report that a Li/S cell employing a cetyltrimethyl ammonium bromide (CTAB)-modified sulfur-graphene oxide (S GO) nanocomposite cathode can be discharged at rates as high as 6C (1C = 1.675 A/g of sulfur) and charged at rates as high as 3C while still maintaining high specific capacity (similar to 800 mA.h/g of sulfur at 6C), with a long cycle life exceeding 1500 cycles and an extremely low decay rate (0.039% per cycle), perhaps the best performance demonstrated so far for a Li/S cell. The initial estimated cell-level specific energy of our cell was 500 W.h/kg, which is much higher than that of current Li-ion cells (similar to 200 W.h/kg). Even after 1500 cycles, we demonstrate a very high specific capacity (similar to 740 mA.h/g of sulfur), which corresponds to similar to 414 mA.h/g of electrode: still higher than state-of-the-art Li-ion cells. Moreover, these Li/S cells with lithium metal electrodes can be cycled with an excellent Coulombic efficiency of 96.3% after 1500 cycles, which was enabled by our new formulation of the ionic liquid-based electrolyte. The performance we demonstrate herein suggests that Li/S cells may already be suitable for high-power applications such as power tools. Li/S cells may now provide a substantial opportunity for the development of zero-emission vehicles with a driving range similar to that of gasoline vehicles.
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