Molybdenum trioxide/polyaniline (MoO3/PANI) composite was prepared first by ion-exchange reaction between aniline (ANI) and dodecylamine (DDA) which was intercalated precursor, and then was formed under the polymerization of ANI within the interlayer space Of MoO3 at 120 degrees C for 3 d in air. According to powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, infrared spectroscopy and electrochemical testing, MoO3/PANI composite has layered structure, and its interlayer spacing is 1.127nm. Moreover, it has high thermal stability with the compound and completes its weight loss at 751.9 degrees C. Electrochemical investigation shows that MoO3 is the major active substance in the MoO3/PANI electrode, and MoO3/PANI electrode demonstrates better conductivity and electrochemical activity than pure MoO3 electrode, attributed to the promotion of Li+ and/or electron transport. in addition, the alternating current impedance proves that if the resistance Of MoO3/PANI electrode reduces apparently, the electrochemical activity will increase correspondingly, the same as the relationship between the ohmic resistance and the electrical conductivity. (C) 2009 Elsevier Inc. All rights reserved.