Refined Tin Nanoparticles by Oxidation-Reduction Treatment for Use in Potassium-Ion Batteries

A unique method is developed to synthesize Sn nanomaterials. Through an oxidation-reduction treatment, Sn particles are refined from the submicron (300 nm) to nanoscale (88 nm). With a series of ex situ and in situ experiments, we confirm that the Sn refinement follows the scattered nucleation and restricted fusion mechanism. The carbon films forming in oxidation play a key role in inducing the refinement as they restrict the agglomeration of Sn nanoparticles to keep the narrow size distribution. When used as anodes for potassium-ion batteries, the obtained Sn nanoparticles restricted in carbon films (r-Sn/C) exhibit enhanced cycling stability and capacity retention. This unprecedented treatment provides some enlightenment to produce functional nanomaterials used for energy storage applications.