Self-assembled 3D Fe3O4/N-Doped graphene aerogel composite for large and fast lithium storage with an excellent cycle performance

Abstract

• A 3D Fe 3 O 4 /NGA with a mesopore is prepared for using in lithium-ion battery anode. • Nitrogen is doped on reduced graphene oxide via hydrothermal and roasting process. • The effect of nitrogen type on electrochemical stability of composite is investigated. • The three-dimensional structure is confirmed for the cycling stability of the anode. A three-dimensional (3D) Fe 3 O 4 / N -doped graphene aerogel composite (Fe 3 O 4 /NGA) was constructed via a simplistic two-step method of hydrothermal reaction-roasting using iron (Ⅱ) phthalocyanine (FePc) and graphene oxide (GO) as raw materials. GO nanosheets can self-assemble into 3D aerogels and be converted into reduced graphene oxides (rGO) in the first step of the hydrothermal process. Further, Fe 3 O 4 /NGA with a strong chemical coupling can be obtained via roasting (the second step) based on the fact that FePc and rGO can be tightly combined under the chemical reaction of oxygen-containing functional groups. The electrochemical properties were studied by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements, which exhibit superior cycling performance with high rate capability as anode applied in a lithium-ion battery. The specific capacity of Fe 3 O 4 /NGA-90 was still up to 1184.8 mAh/g after 500 cycles at a current density of 1 A/g. These exciting results indicate that the 3D Fe 3 O 4 / N -doped graphene aerogel composite exhibits superior performance as an active material for the use of lithium-ion batteries.