Electrocatalyst design has stimulated considerable attention and strenuous effort to tackle a multitude of detrimental issues in lithium–sulfur (Li–S) systems, mainly pertaining to the severe polysulfide shuttle effect and sluggish sulfur redox kinetics. In this context related advances in expediting bidirectional sulfur reactions have lately surged. Nonetheless, the structure–activity correlation and electrocatalytic mechanism remain rather elusive, as a result of elusory active sites, complicated aprotic environments, and multistep conversion pathways. This review summarizes burgeoning strategies in the modulation of heterogeneous and homogeneous electrocatalysts, wherein the advanced electrokinetic measurements, operando instrumental probing, and theoretical simulations are elucidated with an emphasis on deciphering bidirectional sulfur electrochemistry. Notably, a “3s” electrocatalysis model is proposed to deepen the mechanistic understanding in this realm. Finally, a development roadmap is sketched and future research layouts are discussed, aiming in essence, to realize favorable bidirectional redox kinetics and ultimately bridge the gap between reality and ideal systems in working Li–S batteries.

中文翻译：

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锂硫电池中双向硫氧化还原的电催化剂调控：从战略探索到机理理解

电催化剂设计引起了人们对解决锂硫（Li-S）系统中许多有害问题的极大关注和努力，主要与严重的多硫化物穿梭效应和缓慢的硫氧化还原动力学有关。在这种情况下，加速双向硫反应的相关进展最近激增。尽管如此，由于难以捉摸的活性位点、复杂的非质子环境和多步转化途径，结构-活性相关性和电催化机制仍然相当难以捉摸。本综述总结了调制非均相和均相电催化剂的新兴策略，其中先进的电动测量、操作仪器探测、阐明了理论模拟，重点是破译双向硫电化学。值得注意的是，提出了“3s”电催化模型以加深对该领域的机理理解。最后，勾勒出发展路线图并讨论了未来的研究布局，旨在实现有利的双向氧化还原动力学，并最终弥合工作锂硫电池的现实与理想系统之间的差距。