Impedance of Lithium Electrodes in a Propylene Carbonate Electrolyte

Abstract

Different models of homogeneous, composite, and stratified surface layers have been investigated for the interpretation of impedance measurements of lithium electrodes in organic electrolytes. The surface layers are assumed to consist of organic and inorganic compounds with the properties of solid and polymer electrolytes. Comparison of predicted impedance spectra with those measured for surface layers formed in a molar solution of lithium percholate in propylene carbonate shows that with the use of assumed film properties two interphase models provide thicknesses of surface layers which agree with previous ellipsometer measurements: In a compact‐stratified layer (CSL) model, the surface layer is assumed to consist of two sublayers of solid and polymer electrolytes; in a solid‐polymer layer (SPL) model, the surface layer is assumed to consist of a mixture of solid and polymer electrolytes.