Reduced Shuttle Effect of Lithium−sulfur Batteries by using a Simple Graphite‐Modified Separator with a Preformed SEI Film

This is the authors' abstract. We don't add key points for this paper.

Lithium−sulfur (Li−S) batteries, which possess a high theoretical capacity of 1675 mAh g−1 and energy density of 2600 Wh kg−1, are regarded as appealing candidates for next‐generation power storage systems. However, poor electrochemical performance, mainly attributed to polysulfide diffusion, obstructs their practical application. Herein, a simple graphite‐modified separator with a preformed solid electrolyte interphase (SEI) is first fabricated to suppress the polysulfide shuttle. Particularly, the formed SEI film on the graphite surface inhibits the graphite exfoliation caused by co‐intercalation of solvents. Thus, the stable graphite layer with a preformed SEI can function as an effective physical barrier to suppress the polysulfide shuttle and enhance the utilization of the trapped active material. As a result, the cell using the graphite‐modified separator exhibits a high capacity of 698 mAh g−1 (0.2 C) after 100 cycles with a low capacity decay of 0.13 % per cycle. Even under relatively high sulfur loading (2.5 mg cm−2), it shows a reversible capacity of 519 mAh g−1 after 200 cycles.