Hybrid of Co_3Sn_2@Co nanoparticles and nitrogen-doped graphene as a lithium ion battery anode

摘要

A facile strategy was designed for the fabrication of hybrid of Co _3Sn_2@Co nanoparticles (NPs) and nitrogen-doped graphene (NG) sheets through a hydrothermal synthesis, followed by annealing process. Core-shell architecture of Co_3Sn_2@Co pin on NG is designed for the dual encapsulation of Co_3Sn_2 with adaptable ensembles of Co and NG to address the structural and interfacial stability concerns facing tin-based anodes. In the resulted unique architecture of Co _3Sn_2@Co-NG hybrid, the sealed cobalt cover prevents the direct exposer of Sn with electrolyte because of encapsulated structure and keeps the structural and interfacial integrity of Co_3Sn_2. However, the elastically strong, flexible and conductive NG overcoat accommodates the volume changes and therefore brings the structural and electrical stabilization of Co_3Sn_2@Co NPs. As a result, Co_3Sn_2@Co-NG hybrid exhibits extraordinary reversible capacity of 1615 mAh/g at 250 mA/g after 100 cycles with excellent capacity retention of 102%. The hybrid bears superior rate capability with reversible capacity of 793.9 mAh/g at 2500 mA/g and Coulombic efficiency nearly 100%.