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 degrees 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.