The storage characteristics and surface basicity of Li-rich layered Li[Li0.2Ni0.2Mn0.6]O-2 cathode material are investigated. The electrochemical performance deteriorates during the storage in air, and the discharge capacity decreases greatly after stored for 5 months. HRTEM results show a thin layer forms on the surface of particle and becomes thicker with the storage time prolongs. The analysis of FTIR and XPS suggests that the component of the layer mostly is Li2CO3. The surface basicity of various cathode materials is determined by CO2 adsorption microcalorimetry measurement. The results show that the basicity of the active materials is directly related to their stable during storage. It is probably an effective and precise method to evaluate the storage characteristics of the active materials via determining their basic properties instead of testing after a long-term storage. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.065301jes] All rights reserved.