As one of the most promising candidates for next‐generation energy storage systems, lithium‐sulfur (Li‐S) batteries have gained wide attention owing to their ultrahigh theoretical energy density and low cost. Nevertheless, their road to commercial application is still full of thorns due to the inherent sluggish redox kinetics and severe polysulfides shuttle. Incorporating sulfur cathodes with adsorbents/catalysts has been proposed to be an effective strategy to address the foregoing challenges, whereas the complexity of sulfur cathodes resulting from the intricate design parameters greatly influences the corresponding energy density, which has been frequently ignored. In this review, the recent progress in design strategies of advanced sulfur cathodes is summarized and the significance of compatible regulation among sulfur active materials, tailored hosts, and elaborate cathode configuration is clarified, aiming to bridge the gap between fundamental research and practical application of Li‐S batteries. The representative strategies classified by sulfur encapsulation, host architecture, and cathode configuration are first highlighted to illustrate their synergetic contribution to the electrochemical performance improvement. Feasible integration principles are also proposed to guide the practical design of advanced sulfur cathodes. Finally, prospects and future directions are provided to realize high energy density and long‐life Li‐S batteries.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/sus2.42

Designing principles of advanced sulfur cathodes toward practical lithium‐sulfur batteries

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.

Electrocatalyst Modulation toward Bidirectional Sulfur Redox in Li–S Batteries: From Strategic Probing to Mechanistic Understanding

Although single-atom catalysts (SACs) have been largely explored in lithium-sulfur (Li-S) batteries, the commonly reported nonpolar transition metal-N4 coordinations only demonstrate inferior adsorption and catalytic activity toward shuttled lithium polysulfides (LiPSs). Herein, single Fe atoms with asymmetric coordination configurations of Fe-N3C2-C were precisely designed and synthesized as efficient immobilizer and catalyst for LiPSs. The experimental and theoretical results elucidate that the asymmetrically coordinated Fe-N3C2-C moieties not only enhance the LiPSs anchoring capability by the formation of extra π-bonds originating from S p orbital and Fe dx2-y2/dxy orbital hybridization but also boost the redox kinetics of LiPSs with reduced Li2S precipitation/decomposition barrier, leading to suppressed shuttle effect. Consequently, the Li-S batteries assembled with Fe-N3C2-C exhibit high areal capacity and cycling stability even under high sulfur loading and lean electrolyte conditions. This work highlights the important role of coordination symmetry of SACs for promoting the practical application of Li-S batteries.

Strengthened d-p Orbital Hybridization through Asymmetric Coordination Engineering of Single-Atom Catalysts for Durable Lithium-Sulfur Batteries.

Synergistic interlayer and defect engineering of hydrated vanadium oxide toward stable Zn-ion batteries

To tackle the parasitic polysulfides shuttle effect of lithium sulfur batteries, we herein report highly active Mn/Co-N-C catalyst with dual atom Mn/Co active sites coordinated on N doped carbon support....

Jiao An

Papers

Achieving reversible precipitation-decomposition of reactive Li2S towards high-areal-capacity lithium-sulfur batteries with a wide-temperature range