Interfacial Bonding of Metal‐Sulfides with Double Carbon for Improving Reversibility of Advanced Alkali‐Ion Batteries

Abstract Engineering interfacial properties of metal‐sulfides toward excellent electrochemical capability is imperative for advanced energy‐storage materials. However, they still suffer from an unclear mechanism of capacity fading, along with ineffective physical–chemical evolution. Herein, a highly‐effective Sb 2 S 3 with double carbon is designed with interfacial SbC bonds and double carbon, which boosts promoting of ion transferring and alleviates the separation of both active phases (Sb, S). Through “voltage‐cutting” manners, the key elements of capacity improvement about phase transitions are further determined. As expected, even at 5.0 A g −1 , the lithium‐storage capacity remains about 674 mAh g −1 . Utilized as sodium ion battery (SIB) anode, the rate capacity still reaches up to 366 mAh g −1 at 3.0 A g −1 , much larger than that of Sb 2 S 3 . Obtaining the full cell of Ni–Fe Prussian blue analog versus M‐Sb 2 S 3 @DC, the reversible capacity is 330 mAh g −1 at 0.5 A g −1 . Supported by kinetic analysis, the excellent rate properties are determined by the surface‐controlling behaviors, mainly resulting from the decreased capacitive resistance and improved ion moving. Furthermore, the reassembling evolution of active phases is revealed in detail by ex situ techniques. This work is expected to offer significant insights into interfacial evolutions toward advanced energy‐storage systems.