Graphene/Fe₂O₃/SnO₂ Ternary Nanocomposites as a High-Performance Anode for Lithium Ion Batteries

Abstract

We report an rGO/Fe 2 O 3 /SnO 2 ternary nanocomposite synthesized via homogeneous precipitation of Fe 2 O 3 nanoparticles onto graphene oxide (GO) followed by reduction of GO with SnCl 2 . The reduction mechanism of GO with SnCl 2 and the effects of reduction temperature and time were examined. Accompanying the reduction of GO, particles of SnO 2 were deposited on the GO surface. In the graphene nanocomposite, Fe 2 O 3 nanoparticles with a size of ∼20 nm were uniformly dispersed surrounded by SnO 2 nanoparticles, as demonstrated by transmission electron microscopy analysis. Due to the different lithium insertion/extraction potentials, the major role of SnO 2 nanoparticles is to prevent aggregation of Fe 2 O 3 during the cycling. Graphene can serve as a matrix for Li + and electron transport and is capable of relieving the stress that would otherwise accumulate in the Fe 2 O 3 nanoparticles during Li uptake/release. In turn, the dispersion of nanoparticles on graphene can mitigate the restacking of graphene sheets. As a result, the electrochemical performance of rGO/Fe 2 O 3 /SnO 2 ternary nanocomposite as an anode in Li ion batteries is significantly improved, showing high initial discharge and charge capacities of 1179 and 746 mAhg –1, respectively. Importantly, nearly 100% discharge–charge efficiency is maintained during the subsequent 100 cycles with a specific capacity above 700 mAhg –1 .