Improved coulombic efficiency in nanocomposite thin film based on electrodeposited-oxidized FeNi-electrodes for lithium-ion batteries

Electrochemical deposition from Ni2+ and Fe2+ using sulfate and nitrate solutions is carried out under galvanostatic regime. The resulting films are oxidized and examined in lithium test cells as potential anode materials for lithium-ion batteries. X-ray diffraction, XPS and SAED-TEM analyses revealed a thin film based on nanocomposite NiO and Fe2O3. Cycling studies show the smallest discharge polarization ever reported during the conversion reactions of metal oxides at similar to 0.8 V. Unlike typical transition metal oxides, the amorphous oxidized material exhibited low irreversibility from first to second discharge (similar to 15%) and a distinctive plateau on consecutive discharge branches. The changes in the film thickness on increasing deposition time and the crystallization phenomena on annealing the deposits strongly affect the electrochemical behavior. The present approach allows preparing a powder free electrode with improved coulombic efficiency directly on the current collector and opens a set of novel preparation routes in this field with intriguing results. (c) 2013 Elsevier B.V. All rights reserved.