Aluminum-doped lithium iron phosphate was synthesized with a modified sol–gel process. The sol–gel derived cathodes show much higher conductivity than those prepared by a solid-state method. The conductivity is 8×10−2 Scm−1 for the Al-doped LiFePO4/carbon composite powders synthesized at 850°C for 2h, as determined using AC impedance spectroscopy. The electrodes consisting of the Al-doped LiFePO4/carbon composite powders were fabricated for the electrochemical characterization and showed a specific capacity of about 150mAhg−1 at C/40 rate. Not only the conductivity of the crystal lattice but also the conductivity of the grain boundary is enhanced for the nano-sized Al-doped LiFePO4/carbon composite powders.