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

Zhu, Yu-Jie; Bi, Chen-Xi; Zhao, Meng; Li, Zheng; Feng, Wen-Jun; Sun, Furong; Zhang, Xue-Qiang; Li, Bo-Quan et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

Lithium-sulfur (Li-S) batteries are promising next-generation energy storage systems due to their ultrahigh theoretical energy density of 2600 Wh kg<sup>-1</sup>. 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 Li<sub>2</sub>S<sub>8</sub> and Li<sub>2</sub>S<sub>6</sub> is higher than Li<sub>2</sub>S<sub>4</sub>. 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 Li<sub>2</sub>S<sub>4</sub> electrolyte in comparison with Li<sub>2</sub>S<sub>8</sub> and Li<sub>2</sub>S<sub>6</sub> 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.