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

Abstract

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@Al2O3@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@Al2O3@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@Al2O3@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.