Surface reactions constitute the foundation of various energy conversion/storage technologies such as the lithium–sulfur (Li–S) batteries. To expedite surface reactions for high‐rate battery applications demands for in‐depth understanding of reaction kinetics and rational catalyst design. Herein, we proposed an in‐situ extrinsic‐metal etching strategy to activate an inert monometal nitride of hexagonal Ni3N through iron‐incorporated cubic Ni3FeN. In‐situ etched Ni3FeN regulates polysulfide‐involving surface reactions at high rates. Advanced electron microscopy was employed to unveil the mechanism of in‐situ catalyst transformation. The Li–S batteries modified with Ni3FeN exhibited superb rate capability, remarkable cycling stability at a high sulfur loading of 4.8 mg cm−2, and lean‐electrolyte operability. This work opens up the exploration of multimetallic alloys and compounds as kinetic regulators for high‐rate Li–S batteries and also unearth
the understanding of catalytic surface reactions and the role of defect chemistry.
