Achieving Stable and Ultrafast Potassium Storage of Antimony Anode via Dual Confinement of MXene@Carbon Framework.

Antimony‐based anode materials are recognized for their high potassium storage capacities and appropriate operating potentials. However, the large volume expansion of Sb during the potassiation/depotassiation process, which results in a quick capacity decay, severely limits its practical application in potassium‐ion batteries (PIBs). Here, a carbon‐coated Sb/MXene heterostructure composite (CSM) is synthesized by adsorption of Sb3+ on MXene nanosheets via Sb‐O‐Ti bonds followed by carbothermic reduction to construct dual‐confined MXene@carbon conductive framework capable of withstanding high volume expansion of Sb and conducive to enabling accelerated electron transfer kinetics. The CSM composite, particularly CSM‐700, when configured as an anode for PIBs, realized high capacity (484.4 mAh g−1 at 0.1 A g−1), an ultra‐stable cycling performance with a high reversible capacity of 435.9 mAh g−1 at 0.1 A g−1 after 100 cycles corresponding to a capacity retention rate of 90.0%, and superior rate performance of 323.0 mAh g−1 at 1 A g−1. The proposed strategy offers a simple route to construct high‐performance Sb‐based anodes for advanced PIBs. [ABSTRACT FROM AUTHOR]