Interfacial Stability of Lithium in Non-Aqueous Gel Polymer Electrolyte Cells

摘要

Solid polymer electrolytes (SPE) prepared by crosslinking non-aqueous gel polymerprecursors in dimethyl sulfoxide-lithium salt media were investigated by a.c. conductivity measurements. These materials exhibit an ionic conductivity of about 10-3 S/cm at 25 deg C. Electrochemical cells of the type Li/SPE/Li and Li/SPE/M where M = Ni, Al SS were fabricated. Cyclic voltammograms on the asymmetric cells indicate that the electrolyte decomposition potential is about 3.6 volts. The shape of the repetitive cyclic voltammograms within the stability domain indicated that the lithium plating/stripping process is more efficient in the case of Li/SPE/Ni Li/SPE/Al than Li/SPE/SS asymmetric cells. The a.c. impedance measurements on symmetric Li/SPE/Li cells exhibited two well define semi-circles with three intercepts on three real-axis. The observed increase in impedance with time was indicative of passivating film formation at the interface. The growth of the film stabilized at a finite value, permitting lithium cyclability. Keywords: Polymer electrolyte, Solid state battery, Electric batteries, Interfacial impedance. (js)