Effects of radio-frequency sputtering powers on the microstructures and electrochemical properties of LiCoO2 thin film electrodes

Different LiCoO2 thin films are prepared with radio-frequency (RF) sputtering technique. The physical and electrochemical properties of the films are characterized with X-ray diffraction (XRD), Raman scattering spectroscopy (RS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and charge-discharge experiments. The films obtained at high sputtering power such as 150 W or 200 W which are composed of bigger particles or larger pieces of the target material exhibit better electrochemical performance than the films obtained at low sputtering powers. It should avoid further annealing process of the thin film electrodes. The experimental results have explained why the as-deposited films become better crystallized and therefore their charge-discharge performance is further improved with the increase of the sputtering power. (C) 2008 Elsevier B.V. All rights reserved.