LiFePO4 as a cathode material for rechargeable lithium batteries was prepared by hydrothermal process at 170 degrees C under inert atmosphere. The starting materials were LiOH, FeSO4, and (NH4)(2)HPO4. The particle size of the obtained LiFePO4 was 0.5 mu m. The electrochemical properties of LiFePO4 were characterized in a mixed solvent of ethylene carbonate and diethyl carbonate (1:1 in volume) containing 1.0 mol dm(-3) LiClO4. The hydrothermally synthesized LiFePO4 exhibited a discharge capacity of 130 mA h g(-1), which was smaller than theoretical capacity (170 mA h g(-1)). The annealing of LiFePO4 at 400 degrees C in argon atmosphere was effective in increasing the discharge capacity. The discharge capacity of the annealed LiFePO4 was 150 mA h g(-1). (c) 2006 Elsevier B.V. All rights reserved.