Molten‐Salt‐Assisted Industrial‐Scale Fe ₃ C‐Based Nano‐Reactors Endow Dynamic Regulation from Polysulfides Guided Transfer to Enforced Transformation Mechanism

Abstract Electrocatalysts accelerate the redox kinetics of polysulfides in lithium–sulfur batteries (LSBs), yet their directional reaction dynamics demand a rational design of both structure and electronic behavior. However, scalable and efficient synthesis strategies remain a bottleneck for the practical deployment of advanced catalysts. Herein, the kilogram‐scale fabrication of 1D nanoreactors comprising Fe ₃ C nanocrystals encapsulated within nitrogen‐doped carbon nanotubes (Fe ₃ C@NCNT) is reported, synthesized via a simple molten‐salt‐assisted pyrolysis method. The resulting core–shell heterostructure forms a delocalized electron‐active region at the Fe ₃ C/NCNT interface, which guides negatively charged polysulfides toward the electron‐deficient Fe ₃ C core and positively charged Li⁺ toward the electron‐rich NCNT shell to promote the dynamic mass transfer. As discharge proceeds, Li ₂ S is electrostatically driven toward the inner cavity for stable deposition under the influence of an internal electron density gradient to accelerate forced conversion. This dynamic electron‐regulated pathway enables vectorial polysulfide conversion and promotes enhanced sulfur redox kinetics (LiPSs), refining the conversion process in the nano‐confined space. After verification, both coin and pouch cells based on Fe ₃ C@NCNT deliver application‐relevant electrochemical performance. This work provides an industrial‐scale manufacturing process and perceives elucidation of the vectoriality of polysulfide multi‐electron transfer and the structure‐activity relationship within active substrates.