Interfacial Charge‐Transfer Kinetics Regulate Na ₂ S Deposition by Recycled V Single‐Atom Catalysts for Durable Na–S Batteries

ABSTRACT

Na ₂ S, as the terminal discharge product of room‐temperature sodium–sulfur (Na–S) batteries, is electronically and ionically insulating. When it deposits as a compact film on the cathode, the cathode will become passivated, hindering electron transport and inhibiting further sulfur conversion reactions. Existing catalyst strategies promote the formation of Na ₂ S thermodynamically by enhancing polysulfide adsorption, but this does not address the kinetics passivation issue. Here, we adopt the exchange current density ( j ₀ ) as a kinetic descriptor of the Na ₂ S nucleation mode. Finite‐element simulations reveal that increasing j ₀ drives the nucleation pathway from progressive to instantaneous nucleation. The deposit morphology then evolves from a compact passivating film to uniformly dispersed nanoparticles, and ion and electron transport channels are preserved. This pathway prevents Na ₂ S aggregation and electrode passivation, maintaining electrochemical activity at deep discharge. Guided by this kinetic insight, nitrogen‐doped porous carbon‐supported V single‐atom catalysts (NPC‐V SACs) with high apparent j ₀ were fabricated, and instantaneous Na ₂ S nucleation was achieved on their surfaces. The resulting Na–S battery retains 976.3 mAh g ⁻¹ after 200 cycles at 0.2 A g ⁻¹ , with a decay rate of only 0.08% per cycle. This work establishes a kinetic design perspective for regulating Na ₂ S nucleation in durable Na–S batteries.