Preparation of dual layers N-doped Carbon@Mesoporous Carbon@Fe^sub 3^O^sub 4^ nanoparticle superlattice and its application in lithium-ion battery

Nanostructured Fe3O4, as a typical transition metal oxide material, has been widely used as high capacity anode in lithium ion batteries (LIBs). In order to further exerting its Li storage capacity, herein, we reported a rationally designed dual carbon shells coated Fe3O4 nanoparticle (NP) superlattices with mesoporous carbon (MC) and N-doped carbon (NC) as the dual shells. The inner mesoporous carbon shell could effectively buffer the volume change and promote the conductivity of Fe3O4 NP superlattices, and the outside N-doped carbon shell can ease the structure pulverization. N-doped carbon@mesoporous carbon@Fe3O4 NP superlattices (NC@MC@Fe3O4 NP superlattice) showed superior electrochemical performance, including high specific capacity (838 mAh/g at 0.5 A/g after 150 cycles), unique rate capacity (322 mAh/g at 5 A/g) and ultrahigh cycling capacity (576 mAh/g at 2 A/g after 500 cycles).