Smart surface coatings of silicon (Si) nanoparticles are shown to be good examples for dramatically improving the cyclability of lithium-ion batteries. Most coating materials, however, face significant challenges, including a low initial Coulombic efficiency, tedious processing, and safety assessment. In this study, a facile sol-gel strategy is demonstrated to synthesize commercial Si nanoparticles encapsulated by amorphous titanium oxide (TiO ), with core-shell structures, which show greatly superior electrochemical performance and high-safety lithium storage. The amorphous TiO shell (≈3 nm) shows elastic behavior during lithium discharging and charging processes, maintaining high structural integrity. Interestingly, it is found that the amorphous TiO shells offer superior buffering properties compared to crystalline TiO layers for unprecedented cycling stability. Moreover, accelerating rate calorimetry testing reveals that the TiO -encapsulated Si nanoparticles are safer than conventional carbon-coated Si-based anodes.

Silicon is one of the most promising anode materials for lithium‐ion batteries because of the highest known theoretical capacity and abundance in the earth' crust. Unfortunately, significant “breathing effect” during insertion/deinsertion of lithium in the continuous charge‐discharge processes causes the seriously structural degradation, thus losing specific capacity and increasing battery impedance. To overcome the resultant rapid capacity decay, significant achievements has been made in developing various nanostructures and surface coating approaches in terms of the improvement of structural stability and realizing the long cycle times. Here, the recent progress in surface and interface engineering of silicon‐based anode materials such as core‐shell, yolk‐shell, sandwiched structures and their applications in lithium‐ion batteries are reviewed. Some feasible strategies for the structural design and boosting the electrochemical performance are highlighted. Future research directions in the field of silicon‐based anode materials for next‐generation lithium‐ion batteries are summarized.

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A core-shell-shell heterostructure of Si nanoparticles as the core with mesoporous carbon and crystalline TiO as the double shells (Si@C@TiO) 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), 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 TiO 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@TiO core-shell-shell nanoparticles are proven to show excellent Li storage properties. It delivers high reversible capacity of 1726 mA h g over 100 cycles, with outstanding cyclability of 1010 mA h g even after 710 cycles.