Nanocrystalline ZnFe[sub 2]O[sub 4] and Ag-Doped ZnFe[sub 2]O[sub 4] Films Used as New Anode Materials for Li-Ion Batteries

Nanocrystalline and thin films have been prepared by reactive pulsed laser deposition, and used as anode materials for Li-ion batteries for the first time. X-ray diffraction (XRD) and scanning electron microscopy measurements showed that the prepared films were composed of a nanocrystalline structure with the average particle size less than 100 nm. The initial reversible capacity of and film electrodes reached 556 and 700 mAh/g, respectively, at a current density of 10 μA cm −2 between 0.01 and 3.0 V. The film electrode exhibited better cyclability than film electrode, and retained 91% of the reversible capacity up to 100 cycles. According to our results on cyclic voltammetry of cell coupled with ex situ photoelectron spectroscopy and XRD measurements of as-deposited and lithiated film electrodes, we suggest that the mechanism of film reacted with lithium involves reduction of and to metallic Zn and accompanying the formation of Li-Zn alloy. The dramatically improved electrochemical performance of film electrode might be related to the change of the reaction process after silver doping. © 2004 The Electrochemical Society. All rights reserved.