An Anode Material for Lithium Storage: Si@N,S-Doped Carbon Synthesized via In Situ Self-Polymerization

Silicon is one of the most promising candidates for anode materials for next-generation lithium-ion batteries due to its high theoretical capacity. However, the catastrophic volume change upon lithiation/delithiation and the subsequent pulverization result in poor electrochemical performance and hinder its applications. To address this issue, a Si@N,S-doped carbon core–shell structure (Si@NSC) is proposed in this work. The composites are prepared by in situ polymerization and pyrolysis. The as-prepared Si@NSC electrode exhibits a stable capacity of 1720 mAh g–1 at 0.3 A g–1 after 550 cycles with a capacity retention of 90.2%. Compared with commercial silicon and a mixture of Si and C, Si@NSC demonstrates high initial efficiency and superior cyclic stability owing to its unique structure and moderate Si/C ratio. The Si@NSC composites shed light on the application of Si-based anode materials for high-capacity lithium storage.