Dealloyed Fe3O4 octahedra as anode material for lithium-ion batteries with stable and high electrochemical performance

Fe3O4 octahedra are synthesized by dealloying Al-15Fe (at.%) alloy ribbons in 5 mol L-1 NaOH solution at 95 +/- 5 degrees C for 2 h. The electrochemical properties of the Fe3O4 octahedra as anode material for lithium-ion batteries are investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) are employed to study the structural evolution. The results show that the Al can be leached out from Al-15Fe ribbons consisting of alpha-Al (Fe) and Al13Fe4 phases to obtain regular Fe3O4 octahedra. Galvanostatic charge-discharge cycling of the Fe3O4 octahedra in half cell configuration with lithium at 50 mA g(-1) current density exhibits first discharge capacity of 1077 mA h g(-1), 16.3% higher than the theoretical capacity of Fe3O4. The cell shows stability at charge-discharge rate of 50 mA g(-1), and good capacity retention rate up to 38 cycles. The coulombic efficiency of the Fe3O4 octahedra remains as nearly 100% except for the first cycle. Moreover, dealloying strategy is suggested to be facile in large-scale production of superior anode materials for lithium-ion batteries, indicating its promising prospect for practical application. (C) 2014 Elsevier B.V. All rights reserved.