Cage-like Silicene/CNT Microspheres Synthesized by a Topochemical Reaction as Anodes for Enhanced Stable Lithium-Ion Batteries

Abstract

Silicene has recently received increasing attention as an anode material in lithium-ion batteries (LIBs) due to its unique architectural properties. However, the synthesis of silicene still remains challenging, which limits its practical applications. In this work, silicene nanosheets with multilayer stacks are synthesized by the topochemical method and successfully combined with carbon nanotubes (CNTs) to form a cage-like structure composite. Benefiting from the hierarchical structure and two-dimensional active material, the cage-like silicene/CNTs increases the ionic and electric conductivity while reducing the volume expansion and relieving swelling stress. In addition, calculation also indicates a lower diffusion energy barrier of lithium ions in silicene than that in bulk silicon, which ultimately enhances the rate and cycling performance of the battery. The as-obtained electrodes exhibit a capacity of 690 mA h g–1 at 1 A g–1 after 500 cycles. This work not only introduces a facile topochemical method to prepare materials with two-dimensional multilayer silicene but also provides a new strategy for the application of silicene in LIBs.