Hybrid of Co₃Sn₂@Co Nanoparticles and Nitrogen-Doped Graphene as a Lithium Ion Battery Anode

Abstract

A facile strategy was designed for the fabrication of hybrid of Co₃Sn₂@Co nanoparticles (NPs) and nitrogen-doped graphene (NG) sheets through a hydrothermal synthesis, followed by annealing process. Core–shell architecture of Co₃Sn₂@Co pin on NG is designed for the dual encapsulation of Co₃Sn₂ 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 Co₃Sn₂@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 Co₃Sn₂. However, the elastically strong, flexible and conductive NG overcoat accommodates the volume changes and therefore brings the structural and electrical stabilization of Co₃Sn₂@Co NPs. As a result, Co₃Sn₂@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%