Efficient Catalytic Conversion of Polysulfides by Biomimetic Design of Branch-Leaf Electrode for High-Energy Sodium-Sulfur Batteries

Highlights3D branch-leaf biomimetic design is proposed for high-performance Na-S batteries.The conductive branch can ensure adequate electron and electrolyte supply with the leaf can catalyze the conversion of polysulfides.DFT calculation reveals that the Co nanoparticles can enable fast reduction reaction of the polysulfides;The prepared CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g-1 at 0.1 C and superior rate performance. AbstractRechargeable room temperature sodium-sulfur (RT Na-S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D branch-leaf biomimetic design proposed for high performance Na-S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive branches to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D branch-leaf conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co-S-Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared branch-leaf CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g(-1) at 0.1 C and superior rate performance.

Automated summary

A 3D branch-leaf biomimetic design is proposed for high-performance Na-S batteries, utilizing conductive branches and catalytic leaves to effectively address limitations caused by polysulfides, providing electron and ion pathways for high specific capacity and superior rate performance.