AC IMPEDANCE ANALYSIS OF Li** plus INTERCALATION ON LAYERED STRUCTURE TiS//2 ELECTRODES.

Impedance diagrams of PTFE-bonded TiS//2 electrodes on which lithium intercalation reactions were proceeding were measured at various cathodic potentials in LiBF//4/tetrahydrofuran(THF), LiClO//4/THF and LiClO//4/propylenecarbonate(PC) solutions. It was found that the diagram is basically composed of a distorted capacitive semicircle at higher frequencies and two straight lines with different slopes at lower frequencies. The semicircle is ascribed to the combination of the double layer capacitance, the charge transfer resistance and an additional constant phase impedance due to the effect of electrode porosity. The charge transfer resistance, R//c//t, increased from 0. 0052 OMEGA multiplied by (times) m**2 at 2. 5 V to 0. 25 OMEGA multiplied by (times) m**2 at 1. 8 V with decreasing potential in 2 kmol multiplied by (times) m** minus **3 LiBF//4/THF, showing that the intercalation rate is controlled by the charge transfer process at lower potentials in this solution. In 1 kmol multiplied by (times) m** minus **3 LiClO//4/THF and 1 kmol multiplied by (times) m**31 **3 LiClO//4/PC, values of R//c//t were less than 0. 01 OMEGA multiplied by (times) m**2 at all potentials examined.