Encapsulating iron oxide@carbon in carbon nanofibers as stable electric conductive network for lithium-ion batteries

To meet the requirements for the quick charge for the hybrid electric vehicles (HEVs) or plug-in hybrid electric vehicles (PHEVs), better rate capability is urgently needed for the lithium ion batteries (LIBs). Here in our work, a new anode with excellent rate capability is developed. In this anode, nanoporous iron oxide nanoparticles coated with carbon (designated as Fe2O3@C NPs) are homogeneous distributed in carbon nanofibers (CNFs), which can be designated as Fe2O3@C CNFs. The CNF constrains the nanoporous Fe2O3@C NPs along the longitudinal direction and the fibers are cross-linked, establishing a three dimensional (3D) stable electric conductive network. The nanoporous Fe2O3@C NPs exposed on the surface of CNFs provide more active sites for electrode reactions. The thin carbon shell around the Fe2O3 NPs gives the additional protection and improves the conductive connection between the nanofibers, leading to an integral conductive network which links all the Fe2O3@C NPs. The Fe2O3@C CNFs structure exhibits good capacity retention and excellent rate capacity at high current density.