Electrochemical investigations on electrostatic spray deposited LiMn2O4 films

Abstract

LiMn2O4 films have been prepared using an electrostatic spray deposition (ESD) technique at 400 °C. The deposited films are investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical quartz crystal microbalance (EQCM), cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS). Analysis of LiMn2O4 films using XRD and SEM indicates the formation of a LiMn2O4 single spinel phase with a uniform and dense film. On the other hand, electrochemical investigation in a non-aqueous electrolyte (1 M LiClO4+EC+DEC) suggests the formation of surface film after the initial dissolution of Li2CO3 layer, the mass of surface film has been calculated from the resonant frequency curve and is about 1.2% of entire LiMn2O4 film. The results of CV, EQCM and EIS studies are discussed in terms of changes in surface electrochemical properties during the lithium insertion–extraction process.