Ultrathin Si Nanosheets Dispersed in Graphene Matrix Enable Stable Interface and High Rate Capability of Anode for Lithium‐ion Batteries

Abstract Owing to the thinness and large lateral size, 2D Si materials exhibit very promising prospects as the high‐performance anodes of lithium‐ion batteries (LIBs). However, the facile synthesis of ultrathin 2D Si nanosheets (Si‐NSs) and their efficient application still remain a great challenge. Herein, the fabrication of ultrathin Si‐NSs with the average thickness of < 2 nm is demonstrated using a unique etching‐reduction protocol. After hybridizing with graphene, the as‐prepared Si‐NSs@rGO material delivers ultrahigh rate capability (2395.8 mAh g −1 at 0.05 A g −1 and 1727.3 mAh g −1 at 10 A g −1 ), long cycling lifespan (1000 cycles at 2 A g −1 with a capacity decay rate of 0.05% per cycle) and high average Coulombic efficiency (99.85% during 1000 cycles). The superior performance is attributed to the ultrathinness of Si‐NSs that greatly improves the diffusivity and reversibility of Li + ions. This work provides a strategy for fabricating a high‐rate‐capability anode material to meet the growing demand for high power density LIBs.