Constructing Iron Vacancies in Thiospinel FeIn 2 S 4 to Modulate Fe D ‐Band Center and Accelerate Sodiation Kinetics Enabling High‐Rate and Durable Sodium Storage

Abstract The bimetallic synergies effect and combined conversion/alloying mechanism endow thiospinel FeIn 2 S 4 with great potential as an anode material for sodium‐ion batteries (SIBs). However, their inconsistent synthesis, severe volumetric expansion, and sluggish reaction kinetics typically lead to unsatisfactory cyclic stability and rate capability. Herein, bimetallic organic framework derived FeIn 2 S 4 @N/S‐C microrods with Fe vacancies is presented for fast, durable, and reversible sodium storage. The presence of Fe vacancies significantly modulates the d ‐band center of Fe and decreases the strength of the Fe─S bond for facilitating the sodiation reaction kinetics jointly. Moreover, a thin and stable…