1f:T4c0,Silicon is considered as one of the most favorable anode materials for next-generation lithium-ion batteries. Nanoporous silicon is synthesized via a green, facile, and controllable vacuum distillation method from the commercial Mg₂Si alloy. Nanoporous silicon is formed by the evaporation of low boiling point Mg. In this method, the magnesium metal from the Mg₂Si alloy can be recycled. The pore sizes of nanoporous silicon can be secured by adjusting the distillated temperature and time. The optimized nanoporous silicon (800 °C, 0.5 h) delivers a discharge capacity of 2034 mA h g^-1 at 200 mA g^-1 for 100 cycles, a cycling stability with more than 1180 mA h g^-1 even after 400 cycles at 1000 mA g^-1, and a rate capability of 855 mA h g^-1 at 5000 mA g^-1. The electrochemical properties might be ascribed to its porous structure, which may accommodate large volume change during the cycling process. These results suggest that the green, scalable, and controllable approach may offer a pathway for the commercialization of high-performance Si anodes. This method may also be extended to construct other nanoporous materials.20:T4c1,A core-shell-shell heterostructure of Si nanoparticles as the core with mesoporous carbon and crystalline TiO₂ as the double shells (Si@C@TiO₂) is utilized as an anode material for lithium-ion batteries, which could successfully tackle the vital setbacks of Si anode materials, in terms of intrinsic low conductivity, unstable solid-electrolyte interphase (SEI) films, and serious volume variations. Combined with the high theoretical capacity of the Si core (4200 mA h g^-1), the double shells can perfectly avoid direct contact of Si with electrolyte, leading to stable SEI films and enhanced Coulombic efficiency. On the other hand, the carbon inner shell is effective at improving the overall conductivity of the Si-based electrode; the TiO₂ outer shell is expected to serve as a rigid layer to achieve high structural stability and integrity of the core-shell-shell structure. As a result, the elaborate Si@C@TiO₂ core-shell-shell nanoparticles are proven to show excellent Li storage properties. It delivers high reversible capacity of 1726 mA h g^-1 over 100 cycles, with outstanding cyclability of 1010 mA h g^-1 even after 710 cycles.

	Year	Citations

References