Suppressing Shuttle Effect via Cobalt Phthalocyanine Mediated Dissociation of Lithium Polysulfides for Enhanced Li‐S Battery Performance.

Cationic lithium polysulfides (LiPSs) within ether‐based electrolytes are essential intermediates pivotal in instigating the shuttle effect. Suppressing the generation of cationic LiPSs is crucial for enhancing the performance of high‐energy‐density Li‐S batteries in practical applications. Herein, for the first time, it is demonstrated that cobalt phthalocyanine (CoPc) can significantly enhance the dissociation of LiPSs, leading to a decrease in cationic LiPSs species within the electrolyte. Employing NMR and in‐situ Raman spectroscopy, it is observed that CoPc interacts with sulfur anions within LiPSs, modifying the dissociation equilibrium of LiPSs in 1,2‐dimethoxyethane (DME)/1,3‐dioxolane (DOL) electrolyte. This CoPc‐mediated shift toward dissociation equilibrium reduces the concentration of cationic LiPSs, effectively suppressing the electromigration of LiPSs intermediates toward the Li anode during the charging process of Li‐S battery. As a result, the Li‐S battery enabled a high reversible areal capacity of 4.2 mAh cm−2 at a high sulfur loading of 5.0 mg cm−2 and a low electrolyte/sulfur (E/S) ratio of 3 µL mgs−1. This work affords a promising strategy for tackling the fundamental challenges regarding Li‐S batteries. [ABSTRACT FROM AUTHOR]