A Sb₂S₃ Nanoflower/MXene Composite as an Anode for Potassium-Ion Batteries

Abstract

Potassium-ion batteries (PIBs) are prospective for energy storage systems owing to their low price and high operating voltage. Antimony-based electrode materials have the advantage of high capacity for PIBs, while suffering from huge volume expansion and inferior stability because of the large radius of K⁺. Therefore, developing suitable antimony-based electrode materials with high performance is highly challenging. Herein, self-assembled Sb₂S₃ nanoflowers on the surfaces of MXene (Ti₃C₂) flakes are synthesized through a solvothermal reaction along with a calcination method. The highly conductive two-dimensional Ti₃C₂ soft substrate could not only boost the charge transfer kinetics but also buffer the volumetric expansion of Sb₂S₃ effectively. In addition, the structural stability is enhanced because the Sb₂S₃ nanoflowers are in situ grown on Ti₃C₂ flakes through the strong interfacial coupling. Consequently, the Ti₃C₂-Sb₂S₃ anode exhibits a high reversible capacity of 461 mAh g^-1 at 100 mA g^-1, long cycling life (capacity retention of 79% for 500 cycles), and superior rate performance (102 at 2000 mA g^-1). This work may provide a pathway for designing advanced materials for PIBs.