Search

Silicon anode is one of the most potential large capacity anodes for the refreshing new generation of lithium‐ion batteries. However, the volume changes greatly and the conductivity of Si anode is poor during the lithiation/delithiation process, resulting in inferior discharge/charge performance. To overcome these challenges, we design a core‐dual shell Si@MoO2@C composite by solvent evaporation method and sol‐gel method. The dual shell can surmount the considerable volume expansion as well as further the Li+/e− transport under the synergistic actions of the inner MoO2 and the outer carbon. The MoO2 shell can release the expansion pressure of Si as well as involve the storage of lithium effectively. The Si@MoO2@C anode shows a high ICE (about 80.3 %), a good specific capacity after 100 cycles (1171.7 mAh g−1 at 1 A g−1), and a capacity retention of about 90.1 % (vs 2nd cycle). The excellent electrochemical performances are ascribed to the delicate design of the core‐dual shell structure apparently, which make the Si@MoO2@C to be considered as an extremely promising anode material for LIBs. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • 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. [ABSTRACT FROM AUTHOR]