Comparing the structures and sodium storage properties of centrifugally spun SnO2 microfiber anodes with/without chemical vapor deposition

Abstract

SnO2 microfibers were prepared using a newly developed centrifugal spinning technology with subsequent thermal treatment. The as-prepared SnO2 microfibers were further treated with chemical vapor deposition (CVD) of acetylene using different durations of 30, 60, and 90 min. The surfaces of the CVD-treated SnO2 microfibers are covered with thin carbon layers, and the surface nanoparticles on the SnO2 microfibers were reduced by carbon, producing nano-sized Sn/C whiskers grafted on the backbones. The X-ray diffraction, scanning electron microscopy, and cyclic voltammetry results demonstrate that longer CVD coating duration promotes the formation of Sn/C whiskers on the SnO2 microfibers. The thin carbon coating layers help stabilize the solid electrolyte interface formation while the grafted Sn/C whiskers facilitate better electrolyte–electrode contact. Hence, the CVD-treated SnO2 microfibers exhibit higher initial capacities than the pristine SnO2 microfibers, as well as enhanced capacity retentions after cycling. The results suggest that centrifugal spinning is a promising approach to produce fibrous electrode materials in a rapid and mass production fashion, and the CVD coating process is an effective method to improve the electrochemical performance of the SnO2-based electrode materials.