The electrochemical properties of LiNi0.8Co0.2O2 coated with ZrO2 by three different coating processes (ball-milling, sol-gel method, simple grinding) were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). Results showed that the ZrO2 coating significantly improved the capacity retention of the cathode by suppressing the impedance growth at the interface between electrodes and electrolyte and the best cyclability was obtained in the case of employing the simple grinding for the ZrO2 coating. On the other hand, the initial capacities of the ZrO2-coated LiNi0.8Co0.2O2 cathode were slightly decreased. (c) 2006 Elsevier Ltd. All rights reserved.