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 Fe 2 O 3 @C NPs) are homogeneous distributed in carbon nanofibers (CNFs), which can be designated as Fe 2 O 3 @C CNFs. The CNF constrains the nanoporous Fe 2 O 3 @C NPs along the longitudinal direction and the fibers are cross-linked, establishing a three dimensional (3D) stable electric conductive network. The nanoporous Fe 2 O 3 @C NPs exposed on the surface of CNFs provide more active sites for electrode reactions. The thin carbon shell around the Fe 2 O 3 NPs gives the additional protection and improves the conductive connection between the nanofibers, leading to an integral conductive network which links all the Fe 2 O 3 @C NPs. The Fe 2 O 3 @C CNFs structure exhibits good capacity retention and excellent rate capacity at high current density.