Metal–organic framework derived Fe2O3@NiCo2O4 porous nanocages as anode materials for Li-ion batteries

Abstract

Metal–organic frameworks (MOFs) with high surface areas and uniform microporous structures have shown potential application in many fields. Here we report a facial strategy to synthesize Fe₂O₃@NiCo₂O₄ porous nanocages by annealing core–shell Co₃[Fe(CN)₆]₂@Ni₃[Co(CN)₆]₂ nanocubes in air. The obtained samples have been systematically characterized by XRD, SEM, TEM and N₂ adsorption–desorption analysis. The results show that the Fe₂O₃@NiCo₂O₄ porous nanocages have an average diameter of 213 nm and a shell thickness of about 30 nm. As anode materials for Li-ion batteries, the Fe₂O₃@NiCo₂O₄ porous nanocages exhibit a high initial discharge capacity of 1311.4 mA h g⁻¹ at a current density of 100 mA g⁻¹ (about 0.1 C). The capacity is retained at 1079.6 mA h g⁻¹ after 100 cycles. The synergistic effect of the different components and the porous hollow structure contributes to the outstanding performance of the composite electrode.