Nitrogen-doped carbon hollow spheres packed with multiple nano Sn particles for enhanced lithium storage

Metallic tin has been considered as one of the promising anode candidates for next-generation lithium-ion batteries. However, its poor cycling stability due to the severe volume expansion upon lithiation hinders its further application. Here we propose a shell-to-yolks evolution strategy to synthesize a novel structured Sn-based composite that can well address this issue. The as-prepared composite with multiple Sn cores embedded in one hollow nitrogen-doped carbon sphere is called multiple-yolks-shelled Sn@nitrogen doped carbon (MYS-Sn@NxC). The appropriate voids between Sn particles inside the sphere can well accommodate the volume change during cycles. The robust NxC shell maintains a stable structure of the electrode. As a result, the MYS-Sn@NxC electrode demonstrates excellent electrochemical performance, achieving a long stable reversible capacity of 820 mAh g−1 after 1000 cycles at 2C and nearly 530 mAh g−1 at a high rate of 5C. (1C = 1000 mA g−1).