Nano-silicon embedded in MOFs-derived nitrogen-doped carbon/cobalt/carbon nanotubes hybrid composite for enhanced lithium ion storage

Abstract

Silicon has been deemed to be one of the most prospective anode material for lithium-ion batteries due to its high theoretical capacity, low lithiation potential, and bountiful resources. However, its industrial application can still be impeded by its unsatisfied electrochemical performance, especially poor cycling performance caused by larger volume expansion (about 300%). Herein, we synthesize the silicon-based composites by embedding nano-silicon in Co-based metal–organic frameworks derived nitrogen-doped carbon/cobalt/Co-catalyzed carbon nanotubes porous framework (Si@NC/Co/CNTs). In this architecture, the high conductivity NC/Co/CNTs framework with stable structure owing to the existence of Co can not only significantly improve the electrical conductivity to improve the reaction activity of Si, but also effectively buffer the volume expansion during electrochemical reaction. Hence, the advanced Si@NC/Co/CNTs exhibits a high reversible specific capacity (895 mAh g−1 at 0.1 A g−1) and excellent cycling performance (758 mAh g−1 after 800 cycles at 1 A g−1). Insight into the kinetics reveals that capacitive charge-storage mechanism plays an important role in boosting Li+ storage beneficial from the high specific surface area and accelerated charge transfer. This work propounds a simple route to prepare the Si/C hybrids with improved electrochemical performances for being of great application potential towards lithium-ion batteries anode.