Sulfur Reduction Catalyst Design Inspired by Elemental Periodic Expansion Concept for Lithium-Sulfur Batteries.

Dong, Yangyang; Cai, Dong; Li, Tingting; Yang, Shuo; Zhou, Xuemei; Ge, Yongjie; Tang, Hao; Nie, Huagui et al. · ACS Nano · 2022

basic_science · Level V

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Abstract

The key challenges facing the commercialization of lithium-sulfur (Li-S) batteries are shortening the lithium polysulfide (LiPS) intermediate existence time while accelerating solid-phase conversion reactions. Herein, inspired by highly efficient natural enzymes with Fe/N active sites for oxygen reduction reactions, we report a periodic expansion catalysis concept, i.e., Ru and P synergic stereoselectivity, for designing sulfur reduction reaction (SRR) catalysts. As a proof of concept, a RuP<sub>2</sub>-configuration molecular catalyst was exploited to assemble an interlayer in Li-S batteries that adsorbs LiPSs, optimizes Li<sup>+</sup> migration paths, and catalyzes SRRs. Comprehensive investigation identified the elimination of steric hindrance and strong electron orbital couplings between metallic d band and nonmetallic p band as the main contributing factors of PEC for the SRRs. As a result, the Li-S battery with ∼0.5 wt % catalyst additive showed enhanced cycling stability even under a high sulfur loading (6.5 mg cm<sup>-2</sup>) and low electrolyte/sulfur ratio (9 μL mg<sup>-1</sup>).