Abstract: Nano-structured silicon (Si) has demonstrated high capacity for lithium storage; however, it suffers from unsatisfactory cycling stability caused by large volume change and poor interface stability. Thus, it is very important to construct functional coatings on nano-structured Si to buffer the volume change and im-prove the interface stability. Herein, we successfully construct V₂ O₃ and carbon (C) dual-layer coatings on Si nanoparticles with ultrathin and uniform thickness using a facile spray drying and chemical vapour deposition method. The as-prepared Si@V₂ O₃ @C manifests a high specific capacity of 2230 mAh g^-1 af-ter 100 cycles under the current density of 200 mA g^-1, showing its promising application prospect in lithium storage. In situ electrochemical impedance spectroscopy (EIS) results at different lithiation states and different cycles show a more stable interface resistance of Si@V₂ O₃ @C than pristine Si. The V₂ O₃ and C dual coating layers not only ensure the Si nanoparticles with high structural stability by buffering vol-ume expansion and preventing electrolyte penetration, but also guarantee a superior electron transport rate because of the metallic V₂ O₃ as well as the highly conductive carbon layers.

Key words: Lithium-ion batteries, Silicon anode, Vanadium (III) oxide, Spray drying, SEI layer