AC impedance of the Li(_1-x)CoO₂ electrode

An equivalent circuit for a porous polycrystalline insertion electrode is presented. This model is found to be inadequate to describe the ac response of the Li(1-x)CoO2/LiBF4 in propylene carbonate interface because of the formation of a Li+-ion conducting layer on the surface of the electrode. Lithium diffusion in the electrode is determined by three methods which all indicate a value grater than that reported for TiS2. © 1986.