Planetary explorations of human beings necessitate the research of the influence of gamma-radiation on lithium-ion cells. In this study, the radioactive Co-60 was used as the radiation source. The electrochemical performances of LiCoO2/graphite full cells and LiCoO2/Li half-cells with a LiPF6-based electrolyte were measured before and after the radiation. The structural and compositional changes of the cell components were evaluated by means of X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), and H-1 nuclear magnetic resonance spectroscopy (H-1 NMR). The experimental results indicate that the cell performance is substantially deteriorated after the radiation due to two aspects of changes, i.e. radiation-induced defects in LiCoO2 and production of carboxyl in the electrolyte. The cell degradation is more pronounced for the LiCoO2/C full cells than for LiCoO2/Li half-cells owing to the reaction between active lithium and the carboxyl. (c) 2006 Elsevier Ltd. All rights reserved.