Nanocaging Silicon Nanoparticles into a Porous Carbon Framework toward Enhanced Lithium‐Ion Storage

Abstract Silicon (Si) shows overwhelming promise as the high‐capacity anode material of Li‐ion batteries with high energy density. However, Si‐based anodes are subjected to a limited electrochemical cycling lifetime due to their large volume change. Herein, a honeycomb‐like biomass‐derived carbon nanosheet framework is reported to encapsulate Si nanoparticles via a facile molten salt templating method. The carbon framework provides sufficient void space for effectively accommodating the large volume expansion of Si upon Li + insertion. Moreover, the interconnected carbon skeletons afford fast electron/ion transport pathways for improving the reaction kinetics. Consequently, the porous Si/carbon composite could exhibit a high and stable Li storage capacity of 1022 mAh g −1 at 0.2 A g −1 over 100 cycles along with superior rate capability (555 mAh g −1 at 5 A g −1 ). This study demonstrates an effective structural design strategy for Si‐based anodes toward stable lithium energy storage.