Sn-Sb compounds with novel structure for stable potassium storage

Tin and antimony with layered structure is proposed for the first time for the exceptional anode of potassium ion batteries (PIBs). The Sn-Sb with a layer structure significantly alleviates the structural damage and material pulverization caused by volume expansion during the reaction of potassium ions with metal atoms in the form of insertions, improving the cycling stability of PIBs. Owing to the unique structure, the material can achieve a high capacity of 296 mA h g(-1) at 500 mA g(-1) over 150 cycles, which maintains an average capacity decay of only 0.065% per cycle with Coulombic efficiency of 98%, and have low charge/discharge plateaus (less than 0.5 V). More importantly, the Sn-Sb material with layer structure can still provide a high capacity of 118 mA h g(-1) at 5 A g(-1) with Coulombic efficiency of 99%, which show high rate performance. This work not only solves the problem of rapidly decreasing capacity aroused by the volume expansion of antimony during charging and discharging, but also opens up a new idea about the application of metal material in PIBs.