MICROELECTRODE STUDY OF THE LITHIUM PROPYLENE CARBONATE INTERFACE - TEMPERATURE AND CONCENTRATION-DEPENDENCE OF PHYSICOCHEMICAL PARAMETERS

Selected physicochemical parameters useful for characterizing the metallic lithium electrode exposed to a lithium perchlorate salt in a propylene carbonate solvent are reported as functions of temperature and salt composition. The advantages of using microelectrodes for the measurements are elucidated. Transport parameters governing the electrolyte-phase limiting current density are found to be independent of salt composition over a concentration range of interest for lithium batteries. The Li-Li+ reaction is shown to correspond to classic electron-transfer theory, with a symmetry factor of one-half, as would be expected for a strongly solvated ionic reactant. Simplified equations are derived that allow one to focus on specific aspects of a lithium thin-film battery, demonstrating the utility of the measured parameters for engineering design studies.