A nanocomposite consisting of both LiF and transition metal Co as general inactive electrochemical materials fabricated by pulsed laser deposition exhibits significant electrochemical activity. The charge and discharge measurement indicate that the first charge capacity of 205 mAh/g for the LiF-Co/Li cell is found to release Li. The process of releasing Li from the as-deposited LiF-Co nanocomposite thin films is confirmed by ex situ high resolution transmission electron microscopy and selected area electron diffraction measurements. These results provide direct experimental evidence to support the decomposition of LiF driven by the transition metal Co. LiF-Co nanocomposite electrodes may be found to be a new good candidate for Li storage material. (c) 2006 The Electrochemical Society.