Preparation of Sb nanoparticles in molten salt and their potassium storage performance and mechanism

Sb nanoparticles with a size of 55 nm are fabricated via the reduction of SbCl₃ by metallic Al in the molten salt of SbCl₃ at 80 °C. In situ XRD patterns and ex situ Raman spectra show that the potassium storage mechanism is an alloying-type with the formation of a cubic K₃Sb phase when fully potassiated and an amorphous phase when fully depotassiated. As an anode for potassium-ion batteries, Sb nanoparticles coated with graphene could deliver a reversible capacity of 381 mA h g⁻¹ at 100 mA g⁻¹, and maintain a capacity of 210 mA h g⁻¹ at 500 mA g⁻¹ for 200 cycles.