Promoting “Strong Adsorption” and “Fast Conversion” of Polysulfides in Li‐S batteries Based on Conductive Sulfides Host with Hollow Prism Structure and Surface Defects

Abstract

AbstractThe chemical binding between metal compounds and polysulfides provides a good solution to inhibit shuttle effect in Li‐S batteries. However, the Sabatier principle predicts that overly strong adsorption will commonly hinder the conversion of polysulfides, so building the synergetic effect mechanism between “strong adsorption” and “fast conversion” for polysulfides is a significant strategy. To realize this goal, in this study, the defect‐enriched Co9S8 hollow prisms (DHCPs) as both S host and catalyst material for Li‐S batteries are designed. Based on in situ UV–vis spectroscopy results, it is found that DHCPs can profitably promote the generation of radicals during the discharge process. In the case of the relatively high conversion barrier of “liquid–liquid” reaction, the generated radicals are responsible for the fast conversion reaction via a unique reaction pathway. When the sulfur loading is 4.63 mg cm−2, the cell with DHCP/S cathode delivers a high areal capacity of 4.75 mAh cm−2 at 0.1 C and keeps a high capacity of 2.99 mAh cm−2 after 100 cycles at 0.5 C. This study provides a positive attempt to achieve “strong adsorption” and “fast conversion” of polysulfides simultaneously, which will convincingly boost the development and practical process of Li‐S batteries.