Deciphering the Species-Dependent Polysulfide Corrosion on Lithium Anode Toward Durable Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are promising next-generation energy storage systems due to their ultrahigh theoretical energy density of 2600 Wh kg-1. However, soluble lithium polysulfides (LiPSs) violently corrode Li metal anodes, inducing rapid capacity decay and poor cycling lifespan of Li-S batteries. Herein, the corrosion of different LiPS species on the Li metal anode is systematically investigated. The corrosion rate of Li metal anode by Li2S8 and Li2S6 is higher than Li2S4. The discrepancy in corrosion rate is attributed to the continuous reaction between the LiPSs and Li metal, while the corrosion can hardly be prohibited by the LiPS-generated solid electrolyte interphase. Smaller Li nuclei size, more uniform Li deposition, and more durable cycling of Li metal anodes are found in Li2S4 electrolyte in comparison with Li2S8 and Li2S6 electrolytes. Consequently, a LiPS selection strategy is proposed to selectively inhibit the corrosion of high-order LiPSs and successfully prolong the cumulative capacity by 31% in Li-S batteries. This work clarifies the fundamentals of Li metal anode corrosion by different LiPS species and highlights the rational selection of favorable LiPS species for promoting the cycling durability of Li-S batteries.