Oriented tuning yolk-shell structure for well-confinement and constructing durability of silicon/carbon composite

Silicon-based materials have been recognized as one of the most promising anode materials for next-generation lithium-ion batteries (LIBs) due to its high theoretical specific capacity (4200 mA h g ⁻¹ ), appropriate lithiation potential and abundance in earth. However, the fulsome volume swell and intrinsically low conductivity result in the sluggish kinetics and the limited cycle life, which severely hinders its commercial application. Herein, a composite of Si@hollow nitrogen-doped carbon (Si@HNC) with typical yolk-shell structure is designed and fabricated via a facile strategy coupled super-molecular self-assembly with carbonization. Benefiting from the buffering effect of yolk-shell nanostructure on the volumetric variation, and the excellent conductivity of the porous nitrogen-doped carbon shell, Si@HNC anode material exhibits high structural stability, fast charge and ion transfer. As a result, the Si@HNC sample with the Si content of 54.4 wt% delivers a reversible capacity of 865 mA h g ⁻¹ with the retention of ∼98 % at 1.0 A g ⁻¹ after 300 cycles. More surprisingly, a stable capacity of 1013 mA h g ⁻¹/3.24 mAh cm ⁻² is also retained at 0.5 A g ⁻¹ after 400 cycles even under the high areal loading of 3.2 mg cm ⁻².