Phosphorous Pentasulfide as a Novel Additive for High‐Performance Lithium‐Sulfur Batteries

Abstract Lithium‐sulfur (Li‐S) batteries suffer from rapid capacity decay and low energy efficiency because of the low solubility of lithium sulfide (Li 2 S) in organic solvents and the intrinsic polysulfide shuttle phenomenon. Here, a novel additive, phosphorus pentasulfide (P 2 S 5 ) in organic electrolyte, is reported to boost the cycling performance of Li‐S batteries. The function of the additive is two‐fold: 1) P 2 S 5 promotes the dissolution of Li 2 S and alleviates the loss of capacity caused by the precipitation of Li 2 S and 2) P 2 S 5 passivates the surface of lithium metal and therefore eliminates the polysulfide shuttle phenomenon. A Li‐S test cell demonstrates a high reversible capacity of 900–1350 mAh g −1 and a high coulombic efficiency of ≥90% for at least 40 stable cycles at 0.1 C.