Carbon Disulfide Cosolvent Electrolytes for High-Performance Lithium Sulfur Batteries.

Development of lithium sulfur (Li-S) batteries with high Coulombic efficiency and long cycle stability remains challenging due to the dissolution and shuttle of polysulfides in electrolyte. Here, a novel additive, carbon disulfide (CS2), to the organic electrolyte is reported to improve the cycling performance of Li-S batteries. The cells with the CS2-additive electrolyte exhibit high Coulombic efficiency and long cycle stability, showing average Coulombic efficiency >99% and a capacity retention of 88% over the entire 300 cycles. The function of the CS2 additive is 2-fold: (1) it inhibits the migration of long-chain polysulfides to the anode by forming complexes with polysulfides and (2) it passivates electrode surfaces by inducing the protective coatings on both the anode and the cathode.