Thiuram Vulcanization Accelerators as Polysulfide Scavengers To Suppress Shuttle Effects for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are considered to be one of the most promising alternatives for next-generation high energy-density storage systems. Nevertheless, the notorious "shuttle effect" and sluggish kinetic conversion in actual operation seriously hamper its practical application. Herein, inspired by the action mechanism of vulcanization accelerators, dipentamethylenethiuram tetrasulfide (DPTT) is employed as a novel electrolyte additive. Just like a scavenger, DPTT sweeps lithium polysulfide by a spontaneous instant chemical reaction between them, and the latter is quickly converted to Li2S2, along with the generation of elemental S, which will be reduced to polysulfide again. This is beneficial for relieving the accumulation and shuttling of polysulfide in the electrolyte. Therefore, Li-S batteries with DPTT-containing electrolyte exhibit enhanced capacity retention and improved rate performance. With 4 wt % DPTT additive and 3.03 mg cm-2 S loading, the cell delivers a high initial capacity of 1227.6 mA h g-1 and excellent capacity retention of 914.7 mA h g-1 after 250 cycles at 0.5 C. This study provides a fresh insight into suppressing the shuttle effect and realizing high-performance Li-S batteries.