Stereochemically Active Lone Pairs Promoted High Rate Potassium‐Ion Storage in Bismuth Sulfide

ABSTRACT Bismuth sulfide (Bi ₂ S ₃ ) is a promising potassium‐ion battery anode candidate due to its high theoretical capacity and cost‐effectiveness. However, it experiences severe volume variation and structure collapse during potassiation/depotassiation, leading to inferior cycling stability and rate performance. Herein, a novel stereochemically active lone pairs (SCALP)‐oriented strategy integrated with structural engineering is proposed. Guided by density functional theory calculations predicting that controlled lattice distortion can tune SCALP behavior, a rationally designed Bi ₂ S ₃ anchored within hollow carbon spheres (HCS@Bi ₂ S ₃ ) is synthesized via controlling sulfidation time. SCALP‐oriented approach narrows band gap and strengthens K ⁺ adsorption, improving redox reaction kinetics coupled with efficient ion‐transport pathways in well‐crystallized regions; HCS alleviates volumetric expansion and suppresses potassium‐polysulfide dissolution and shuttling. HCS@Bi ₂ S ₃ ‐3 delivers high reversible capacity (471.5 mAh g ⁻¹ at 200 mA g ⁻¹ ), good high‐rate long‐term cycling stability (147.3 mAh g ⁻¹ after 1000 cycles at 10 A g ⁻¹ ), and excellent rate capability (128.4 mAh g ⁻¹ at 12 A g ⁻¹ ). Full cell paired with 3,4,9,10‐perylenetetracarboxylic dianhydride cathode delivers exciting cycling stability, indicating the practical applications potential of HCS@Bi ₂ S ₃ ‐3. This work highlights SCALP‐modulation as a fundamental strategy optimizing electronic properties, while HCS mitigates volume changes, offering a new pathway for developing fast and stable potassium storage anodes using metal chalcogenides.