A Sulfur-Infused Separator for Boosting Areal Capacity of Li-S Batteries

This study presents a new approach for enabling the development of high-performance lithium-sulfur (Li-S) cells by simply inserting a sulfur-infused separator (SIS) between a common S cathode and a Li metal anode. All solid sulfur electrically isolated from the cathode is electrochemically reduced to polysulfides during the first discharge. Notably, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) studies have demonstrated that the S in the separator disappears completely even when the cell is discharged to 2.1 V in the first cycle. The combination of a SIS with a typical S cathode results in the doubling of the areal capacity with superior cycling stability upon comparison with the control cell. This result demonstrates that the introduction of additional active materials, such as elemental sulfur, to a separator is a highly effective method for the fabrication of Li-S cells with a high areal capacity.