LiFePO4/C composites were prepared from thermal decomposition of Fe(II) organophosphonates Fe[(RPO3)(H2O)] (R = methyl or phenyl group! in the presence of Li2CO3 at high temperature and under inert atmosphere. The compounds were characterized by chemical analysis, thermogravimetric analysis and differential scanning colorimetry, X-ray powder diffraction, and scanning electron microscopy. Electrodes were fabricated for the electrochemical characterization. The cathode material obtained from Fe[C6H5PO3(H2O)] showed a specific energy evaluated at C/10 rate of about 550 Wh kg(-1). The specific power calculated at 30C rate in excess at 14,000 W kg(-1), while the specific energy was about 28% of the theoretical one. No capacity fading was observed upon cycling. (C) 2004 The Electrochemical Society.