Single-Atom Vanadium Catalyst Boosting Reaction Kinetics of Polysulfides in Na-S Batteries.

The practical application of the room-temperature sodium-sulfur (RT Na-S) batteries is hindered by the insulated sulfur, severe shuttle effect of sodium polysulfides, and insufficient polysulfides conversion. Herein, on the basis of first principles calculations, the single atom vanadium anchored on three-dimensional N-doped hierarchical porous carbon matrix (denoted as 3D-PNCV) is designed and fabricated to enhance sulfur reactivity, and adsorption and catalytic conversion performance of sodium polysulfide. The 3D-PNCV host with abundant and active V sites, hierarchical porous structure, high electrical conductivity, and strong chemical adsorption/conversion ability of V-N bonding can immobilize the polysulfides and promote reversibly catalytic conversion of polysulfides toward Na 2 S. Therefore, the as-fabricated RT Na-S batteries can achieve a high reversible capacity (445 mAh g -1 over 800 cycles at 5 A g -1 ) and excellent rate capability (224 mAh g -1 at 10 A g -1 ). The electrocatalysis mechanism of sodium polysulfides is further experimentally and theoretically revealed, which provides a new strategy to develop the highly stable RT Na-S batteries. This article is protected by copyright. All rights reserved.