Magnesium doped Li1-2xMgxFePO4/C (x = 0.00, 0.01, 0.03, 0.05) cathode materials were synthesized by sol-gel method, and the effect of magnesium doping as well as its content on the electrochemical properties for lithium batteries was also investigated. Their morphology was studied with field emission scanning electron microscope and Li1-2xMgxFePO4 materials showed the olivine phase without impurities. The thin carbon layer of Li1-2xMgxFePO4/C was confirmed by high resolution transmission electron microscopy. The magnesium doped Li1-2xMgxFePO4/C particles were smaller than those undoped. The Li1-2xMgxFePO4/C materials showed better cycling behavior than undoped LiFePO4, especially at high C-rate in which Li0.94Mg0.03FePO4/C composition exhibited the best electrochemical properties. (C) 2012 Elsevier Ltd. All rights reserved.