Scavenging of "dead sulfur" and "dead lithium" revealed by integrated-heterogeneous catalysis for advanced lithium-sulfur batteries

The simultaneous engineering of sulfur cathode and Li anode is critical for electrolyte-starved high energy density Li-S batteries, in which slow electrochemical conversions and side chemical reactions of dead sulfur are found to be the determining factors in limiting the sulfur utilization, corresponding to the poor reversible capacity of Li-S batteries. Herein, this work challenges the conventional wisdom of heterogeneous and homogeneous catalyses in Li-S batteries and proposes the concept of integrated-heterogeneous catalysis to simultaneously scavenge the dead sulfur and dead lithium to compensate the active materials sulfur and lithium loss simply through adding a small amount of ZnI${}_2$ into conventional electrolyte of Li-S cells. Regulated by integrated-heterogeneous catalysis, over 1300 h of cycling is realized in Li||Li symmetric cells, revealing superb compatibility of the ZnI${}_2$-incorporated electrolyte with lithium metal. Meanwhile, the ZnI${}_2$ shows good prospects in promoting the reutilization of dead sulfur in both theoretical calculation and experimental tests. Practically, a high initial capacity of 1170 mAh g${}^{-1}$ with decent cycling stability is achieved in electrolyte-starved and high-loading pouch cells (5.0 µL mg${}^{-1}$ and 5.2 mg cm${}^{-2}$). (© 2023 Wiley‐VCH GmbH)