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

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.