Engineering Peculiar Cathode Electrolyte Interphase toward Sustainable and High-Rate Li-S Batteries

The lithium-sulfur battery is considered to be one of the most promising rechargeable energy storage systems because of its high theoretical energy density. Unfortunately, the shuttle effect during cycling causes serious loss of sulfur species and corrosion of the lithium metal anode, resulting in severe capacity decay. This work proposes to completely suppress the shuttle effect of lithium polysulfides (LiPSs) without sacrificing the interfacial Li+ transport, through in situ construction of a compact cathode electrolyte interphase (CEI), which is formed of the reaction between vinylene carbonate (VC), bis(trifluoromethane)sulfonimide ions and LiPSs in a self-limiting manner during the initial discharge process. Hence, the CEI-confined sulfur cathode in the VC-based electrolyte with a solid phase conversion mechanism delivers a long-term cycling stability and high-rate performance, as well as excellent performance under an extreme climate in a subzero temperature of -20 degrees C, limited lithium source with a low N/P ratio of 1.1, and even at mechanical mutilation. The present study reveals an appealing approach to tailor the composition and interfacial structure of sulfur cathodes by in situ construction of a robust, self-healing, and high Li+ conductive CEI from the aspect of electrolyte, and thus completely solve the issue of the shuttle effect.

Automated summary

This study proposes a method to completely suppress the shuttle effect of lithium polysulfides through in situ construction of a compact cathode electrolyte interphase (CEI) using vinylene carbonate (VC), bis(trifluoromethane)sulfonimide ions and LiPSs. This allows for long-term cycling stability and high-rate performance of the sulfur cathode in the electrolyte. The study reveals an appealing approach to tailored sulfur cathodes by in situ construction of a self-healing and high Li+ conductive CEI, effectively solving the shuttle effect issue.