Boosting Reversibility of Conversion/Alloying Reactions for Sulfur-Rich Antimony-Based Sulfides with Extraordinary Potassium Storage Performance

As a new sort of energy storage device, potassium-ion batteries (PIBs) have broad application prospects in the post-lithium-ion battery era. Among the massive anode materials for PIBs, Sb-based sulfides have attracted much attention because of their high potassium storage capacity and abundant resources. However, the huge volume expansion, sluggish K+ storage kinetics, and low reaction reversibility hinder their applications. Here we composited commercial Sb2S5 with cobalt- and nitrogen-codoped carbon (CoNC) via a facile ball-milling strategy, making it an efficient anode material for PIBs. The synergistic effect between the catalysis of Co and buffering of the carbon matrix enhances the reversibility of the conversion/alloying reaction, alleviates the volume inflation, and improves the electrochemical kinetics, thus enabling the electrode to exhibit enhanced electrochemical performance. The prepared anode delivers a high reversible specific capacity (468.5 mAh g–1 at 500 mA g–1) and outstanding cycling stability (98% capacity retention after 150 cycles). In situ characterization clarified its potassium storage mechanism, and theoretical calculations revealed the reason for the improved electrochemical performance.