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

The 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 S3·−${\rm{S}}_3^{\cdot{\bm{ - }}}$ radicals during the discharge process. In the case of the relatively high conversion barrier of “liquid–liquid” reaction, the generated S3·−${\rm{S}}_3^{\cdot{\bm{ - }}}$ 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.

Amorphous/crystalline heterostructure design enables highly efficient adsorption–diffusion–conversion of polysulfides for lithium–sulfur batteries

“…Impressively, a high reversible areal capacity of 3.85 mA h cm −2 is achieved aer 100 cycles, which is comparable to other reports listed in Table S3. † 10,15,17,20,31,44,53,[57][58][59][60]65 As shown in Fig. 6b, the GCD curves still display one charge and two discharge plateaus with a low polarization between charge and discharge processes.…”

“…Catalytic conversion of LiPSs has been proposed as a crucial approach to address these drawbacks. [9][10][11][12] Currently, considerable efforts are devoted to exploring highly active, durable and cost-effective electrocatalysts to modulate the redox reaction kinetics and accelerate LiPS conversion. 13,14 Metal oxides and suldes have been widely investigated as potential sulfur electrocatalysts in the past decade.…”

Tuning Anion Defects in Cu-Fe Spinel Oxides by Sulfur Doping for Boosted Peroxydisulfate Activation

“…Additionally, the crystal fringes along the curved edges are discontinuous, which can offer plentiful defects. In comparison to amorphous or polycrystalline catalysts, these additional active edge sites resulted in higher electron transfer ability 20 . Besides, the deformation of the crystal creates a special strain field around the region of dislocation defects, leading to the formation of vacancies and the accumulation of charges 21…”

Dynamic evolution of electrocatalytic materials for Li–S batteries

“…As mentioned above, adsorption is an important prerequisite for LiPSs catalytic conversion, and thus, relevant studies have designed various catalytic materials to trap LiPSs. [122][123][124] Attributed to the strong interaction between electrocatalysts and LiPSs, some electrocatalysts undergo a series of reconstruction, including new phase formation or component changes. Therefore, a proper study of adsorption-induced electrochemical reconstruction is valuable for a thorough understanding of the real catalytic process and mechanisms.…”