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.