Interface Modulation of Metal Sulfide Anode Materials SnS/ZnS/C for Long‐Cycle‐Life Sodium‐Ion Batteries

Transition metal sulfides (TMS) are considered promising anode materials for sodium‐ion batteries (SIBs) due to their high theoretical capacity and excellent redox reversibility. However, challenges like rapid capacity decay and sluggish reaction kinetics hinder their practical application. This study presents the development of SnS/ZnS heterostructure composites with a porous carbon layer, synthesized using NaCl as a hard template. The L‐SnS/ZnS/C composites exhibit a unique structure that buffers volume stress during sodium insertion/extraction, enhances electron transport, and prevents the agglomeration of active particles. The porous carbon layer increases the contact area with the electrolyte, improving electrochemical stability and rate performance. The L‐SnS/ZnS/C anode demonstrates superior cycling stability, maintaining a reversible capacity of 363.9 mAh g ⁻¹ after 750 cycles at 2 A g ⁻¹ , and high‐rate performance with a capacity of 370.5 mAh g ⁻¹ at 5 A g ⁻¹ . The enhanced performance is attributed to the synergetic effect of the porous carbon layer and heterostructure, which together mitigate volume expansion and enhance ionic and electronic conductivity. This work offers a promising strategy for designing high‐performance TMS‐based anode materials for practical SIB applications.