Li1xCoO2 is an important cathode material for high-energy-density, rechargeable Li-ion batteries. 1-13 Li intercalation into this compound occurs via several phase transition processes. 1, 12 The most distinctive process appears as a pair of sharp reversible peaks in the cyclic voltammetry of these electrodes at a sufficiently slow scan. This process occurs in the 0< x< 0.25 range (3.6-4.0 V vs. Li/Li) and corresponds to a first-order transition between two different hexagonal phases. 1, 12

The present paper deals with the electroanalytical response of Li1xCoO2 electrodes in the given range of x obtained by simultaneous application of slow-scan-rate cyclic voltammetry (SSCV), potentiostatic intermittent titration (PITT), and electrochemical impedance spectroscopy (EIS). 14-17 We previously applied a similar approach for the study of lithiated graphite electrodes, 14-17 which revealed that the electroanalytical behavior of these electrodes may be well understood in terms of the existence of strong attractive interactions between intercalation sites. 18 This paper aims at extending such an approach to Li1xCoO2 electrodes (0< x< 0.25). Similar to lithiated graphite, Li1xCoO2 is also a layered material. 1, 12 Furthermore, our recent studies of several cathode materials. 19 showed that surface films, through which Li ions migrate from solution phase to active mass, cover the Li1xCoO2, as is the case with LixC6. Consequently, similar electrochemical models may fit both LixC6 and Li1xCoO2 electrodes. The present paper provides a basis for the calculation of several important kinetic parameters related to intercalation reactions. Direct comparison among the various electrochemical techniques used is also presented and discussed in terms of applicability and accuracy.