Internally inflated core-buffer-shell structural Si/EG/C composites as high-performance anodes for lithium-ion batteries

A watermelon-like internally inflated core-buffer-shell structural Si/electrochemically exfoliated graphene/C (Si/EG/C) composite is designed and prepared by the industrially established ball milling and spray drying method. Owing to numerous folds and voids in the EG filled between nano silicon and carbon shell, the volume fluctuations of silicon inside the Si/EG/C particles are buffered and lithium ions also could transport fast through the channels. With these advantages, the core-buffer-shell structural Si/EG/C composite demonstrates excellent electrochemical performance. The Si/EG/C anodes in half cells exhibit no degradation of the initial capacity (834 mA h g−1) after 100 cycles. Moreover, the Si/EG/C//LiCoO2 full cells retain almost 100% of the initial discharge capacity after 500 cycles. These results highlight the potential applications of Si/EG/C in the next generation of Li-ion batteries.