Electrochemical studies of spinel LiMn2O4 films prepared by electrostatic spray deposition

An uniform, dense film of spinel LiMn2O4 (thickness, about 0.5 mu m) was prepared by the electrostatic spray deposition method onto a Pt film electrode on Si substrate kept at 400 degrees C. Electrochemical properties of the LiMn2O4 film in a solution of 1 M LiClO4/propylene carbonate were studied by cyclic voltammetry and potential-step chronoamperometry. The oxidation and reduction of the film, which are accompanied by the extraction/insertion of lithium ions, proceeded almost quantitatively around 4 V vs. Li/Li+ with excellent coulombic reversibility. The apparent chemical diffusion coefficient of Li+ in Li1-xMn2O4 spinel phase varied on the order between 10(-10) and 10(-12) cm(2) s(-1) as a function of electrode potentials with minima at the potentials corresponding to the voltammetric current peaks.