IN-SITU CONDUCTIVITY MEASUREMENTS OF LIMN2O4 THIN-FILMS DURING LITHIUM INSERTION EXTRACTION BY USING INTERDIGITATED MICROARRAY ELECTRODES/

Thin films of LiMn2O4 have been prepared by RF magnetron sputtering on interdigitated microarray electrodes. In situ conductivity-potential profiles and cyclic voltammograms during extraction/insertion processe s of Li ions were obtained simultaneously in nonaqueous and aqueous el ectrolyte solutions (1 M LiClO4/propylene carbonate and 1 M LiCl/water ). The electronic conductivity of Li1-xMn2O4 was found not to show met allic transition and maintain its semiconducting state during the extr action/insertion of Li ion. A slight decrease in conductivity was obse rved with increasing the anodic potential, i.e., with increasing x (li thium extraction) and recovered reversibly when the potential returned to the cathodic side (re-insertion of Li ions). Similar results were obtained in both aqueous and nonaqueous electrolyte solutions.