Behavior of Secondary Lithium and Aluminum‐Lithium Electrodes in Propylene Carbonate

The improvement of the l ithium cycling efficiency obtained by substituting an aluminum substrate for a l ithium substrate is explained by means of morphological and kinetic studies of the electrodes in the molar solution LiC104-propylene carbonate. SEM observations show that the insertion rate of the l ithium deposit into a luminum can be sufficiently high so as to avoid dendritic growth; ESCA analysis reveals that propylene carbonate leads to a chemical iormation of a polymeric membrane on the electrodes, which is less important on the a luminum than on the l ithium substrate. Electrochemical impedance measurements a sociated with polarization curve data point out that most of the surface is active, giving rise to an exchange current density of about 17 mA/cm'~; these studies also demonstrate hat diffusion processes in the passivating layer and in the bulk of the electrode are responsible for the l imited l i thium cycling performances with the a luminum substrate. The difficulties encountered in the development of