High specific energy lithium-sulfur battery


Among the alternatives for conventional lithium-ions batteries, the lithium-sulfur (Li-S) battery is an energy storage system of particular interest, due to its high energy density of up to 2567 wh kg-1. Combining the advantages of relative abundance, low cost and the environmental friendliness of sulfur, Li-S batteries have been considered as one of the most promising candidates for the next-generation of batteries. However, any practical applications of Li-S cells are hindered by several significant drawbacks,such as: the low utilization of active materials, rapid capacity degradation, and poor rate capability seriously restrict their large-scale applications in commercial markets. Especially, for its practical application, the safety issues generated from metal lithium anode and low loading mass are urgently required to be addressed. Two strategies have been developed in our work. First, a series of electrolyte additives were developed, such as SOCl2, which can produce a stable SEI films on the surface of lithium anode. As a result, the as-assembled Lithium-sulfur battery delivered an ultra-high discharge capacity (2202.3 mAh g-1 at 400 mA g-1) and excellent rate performance (1348.6 mAh g-1 at 3000 mA g-1), as well as remarkable cycling performance. This study reveals an effective avenue to suppress the Li-dendrites growth and provide a significant step towards safe and high-energy Li-S batteries. Second, carbon felt is employed as the supporting materials of sulfur, and high sulfur loading above 5 mg cm-2 can be easily achieved. Meanwhile, high sulfur utilization still can be well retained.