Infrared and electrochemical studies on Mg intercalated a-MoO3 thin films

MoO3 thin films were intercalated with Mg ions using a standard three-electrode configuration. The concentration of Mg ions was varied from x = 0.1 to x = 0.7, where x is the ratio of intercalated Mg ions and host Mo ions. Infrared (IR) studies were carried out on intercalated and deintercalated films. The effect of Mg ion concentration on the nature of interaction with host ions and cyclability has been investigated by monitoring selected resonance absorption peaks' intensities and spectral locations. The intensities of few characteristic absorption peaks were very sensitive to humidity confirming adsorption of water vapor. The diffusivity (D) of Mg ions has been estimated from Galvanostatic Intermittent Titration Technique (GITT) and the same is correlated with the chemical changes occurring in the films on intercalation. The estimated D values are of the order of 10(-17)-10(-18) cm(2)/s. The D value is found to be a strong function of number of intercalation/ deintercalation cycle. The IR spectrum of deintercalated film, cycled five times, provides evidence of residual ions in the films. (C) 2004 Elsevier B.V. All rights reserved.