Asymmetrically Coordinated p ‐Block Aluminum Single‐Atom Sites for Stable Na─S Batteries

Abstract

ABSTRACT Main‐group metal single‐atom catalysts (SACs) are promising for sodium−sulfur (Na─S) batteries owing to their low toxicity and economic viability, yet their inherently poor catalytic activity limits the electrochemical performance. Moreover, the electronic interplay involving p‐p orbital hybridization between p ‐block metal SACs and sodium polysulfides (Na 2 S n ) remains unclear. Herein, we design efficient aluminum (Al) SACs with a planar asymmetrical Al─O 3 N coordination anchored on carbon materials (Al─O 3 N─C) for Na─S batteries. The introduced N ligand breaks the coordination symmetry, creating localized charge at the Al sites, which enhances p‐p orbital hybridization between Al‐3 p and S‐3 p of Na 2 S n . This effectively suppresses Na 2 S n shuttling and accelerates sulfur redox kinetics. The resulting Al─O 3 N─C/S exhibits a high capacity of 1196 mAh g −1 at 0.1 C after 100 cycles, and an ultralow capacity decay of 0.017% per cycle over 2500 cycles, outperforming most reported d ‐block SACs for Na─S batteries. This strategy of regulating p ‐orbital charge distribution provides a general guideline for the rational design of other efficient main‐group metal SACs.