Facile synthesis of yolk-shell Si@void@C nanoparticles with 3D conducting networks as free-standing anodes in lithium-ion batteries

The low cost and high performance via a simple way of fabrication are considerable challenges for Si-based anode in the application of lithium-ion batteries. In this study, we synthesize a novel free-standing Si/C anode, consisting of yolk (Si)-shell (amorphous carbon) nanoparticles and carbon nanofibers (denoted as Si@void@C/CNFs), via a facile route of template removal and electrospun. The designed yolk-shell structure help buffer the volume expansion of silicon during the discharge/charge cycles, and the intertwined CNFs are conducive to electron fast transmission and guarantee structural integrity. As expected, with a low Si content (∼23 wt%), the self-supporting electrode of Si@void@C/CNFs exhibits a high specific capacity of ∼627.5 mAh g−1 as well as 69.3% capacity retention at 0.1 A g−1 after 100 cycles, better than Si@C/CNFs (20%) and Si/CNFs (9.5%) electrodes. The superior performance of Si@void@C/CNFs indicates that it is an attractive anode material for the practical application of Lithium-ion batteries.