A Universal Spin‐Polarization‐Engineered Antibonding‐Orbital Modulation Paradigm for Accelerating Reaction Kinetics in Ultrahigh‐Rate Sodium‐Ion Batteries

ABSTRACT Conversion‐type anode materials hold great promise for sodium‐ion batteries (SIBs), yet their practical rate performance is fundamentally constrained by sluggish reaction kinetics beyond mass‐transport limitations. Despite notable advances in accelerating ion/electron transport, intrinsically reducing the large reaction kinetic barrier and activation energy associated with robust metal–chalcogen (M─S) bonds remains a long‐standing challenge. In this study, we propose a universal spin‐polarization‐engineered (SPE) antibonding‐orbital modulation paradigm to fundamentally regulate M─S bond strength and enable ultrahigh‐rate sodium storage. As a proof of concept, magnetic manganese heteroatom doping into heterojunctions enhances the saturation magnetization by ∼210%, inducing a spin‐state transition from low‐spin to high‐spin configurations, which increases the electron occupation of antibonding orbitals formed between metal e g orbitals and chalcogen p orbitals, and thereby regulates M─S bond strength. Benefiting from this spin‐engineered electronic reconstruction, Mn‐FeS 2 /CoS 2 anode delivers an ultrahigh‐rate capability of 300 mA h g −1 at 120 A g −1 , together with exceptional long‐term durability (∼100% retention over 13 000 cycles at 100 A g −1 ), ranking among the best record. The generality of this strategy is further validated by extending SPE modulation to other magnetic dopants. Moreover, the industrial‐level pouch cell is assembled to demonstrate the practical potential of this strategy.