Double-shell-structured Si@Al2O3@C nanoparticles as high-performance anode materials for lithium-ion batteries

Silicon is one of the most promising candidates for anode materials of lithium-ion batteries, due to its high theoretical capacity and low working voltage, etc . Nonetheless, silicon has huge volume change during the lithiation/delithiation, resulting in poor cycle performance. Herein, novel double-shell-structured Si@Al 2 O 3 @C nanoparticles are prepared to obtain stable electrochemical performance. The improved performance can be attributed to novel double-shell structure, which greatly improves the conductivity of material, stabilizes solid-electrolyte interface (SEI) film, and releases the expansion stress of silicon. Si@Al 2 O 3 @C nanoparticles deliver a specific capacity of 1316.1 mAh g −1 at 1 A g −1 after 100 cycles, and the average discharge capacity of Si@Al 2 O 3 @C nanoparticles at 4 A g −1 still remains 781.6 mAh g −1 . Additionally, the initial Coulombic efficiency (ICE) of material is as high as 82.9%. This work offers a significant method to further enhance the performance of lithium-ion batteries. • For lithium-ion batteries, double-shell-structured Si@Al 2 O 3 @C anode is reported for the first time. • The double-shell structure can improve conductivity, stabilize SEI film, and release the expansion pressure of silicon. • Si@Al 2 O 3 @C nanoparticles show a high ICE of 82.9% and a reversible capacity of 1316.1 mAh g −1 at 1 A g −1 after 100 cycles. • Simple two-step synthesis.