Polysulfide-Scission Reagents for the Suppression of the Shuttle Effect in Lithium–Sulfur Batteries

Abstract

Lithium-sulfur batteries have become an appealing candidate for next-generation energy-storage technologies because of their low cost and high energy density. However, one of their major practical problems is the high solubility of long-chain lithium polysulfides and their infamous shuttle effect, which causes low Coulombic efficiency and sulfur loss. Here, we introduced a concept involving the dithiothreitol (DTT) assisted scission of polysulfides into lithium-sulfur system. Our designed porous carbon nanotube/S cathode coupling with a lightweight graphene/DTT interlayer (PCNTs-S@Gra/DTT) exhibited ultrahigh cycle-ability even at 5 C over 1100 cycles, with a capacity degradation rate of 0.036% per cycle. Additionally, the PCNTs-S@Gra/DTT electrode with a 3.51 mg cm^-2 sulfur mass loading delivered a high initial areal capacity of 5.29 mAh cm^-2 (1509 mAh g^-1) at current density of 0.58 mA cm^-2, and the reversible areal capacity of the cell was maintained at 3.45 mAh cm^-2 (984 mAh g^-1) over 200 cycles at a higher current density of 1.17 mA cm^-2. Employing this molecule scission principle offers a promising avenue to achieve high-performance lithium-sulfur batteries.