Long-Life Lithium-Sulfur Cells (18650) with Reduced Polysulfide Shuttle (3LS 18650 Cells)

Lithium sulfur batteries can provide higher specific energies compared to lithium-ion batteries but the polysulfide dissolution is a serious issue for Li-S cells, severely limiting their cycle life. Lithium polysulfide formed as intermediates during sulfur reduction and dissolved in conventional liquid electrolytes diffuse to the anode to react and increase anode impedance, decrease active sulfur and finally reduce coulombic efficiency. All these phenomena manifest in poor cycle life for sulfur cathode, which makes it difficult to utilize the high specific energies possible with Li-S cells. Lyten proposes to address this problem in multiple ways, i.e., by adding metal chalcogenides to the cathode for æchemicallyÆ trapping polysulfides, by coating cathodes with polymer/inorganic coating to block the release of polysulfideĀ from cathode and by developing electrolyte with low solubility for polysulfides. Successful materials from this study will be integrated with new Li alloy anodes with surface coatings and modified commercial separators into 18650 cells to demonstrate performance improvement, especially cycle life at different depths of discharge for satellite applications.