ELECTROCHEMICAL STUDIES OF SPINEL LIMN2O4 FILMS PREPARED BY ELECTROSTATIC SPRAY DEPOSITION

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