Electrochemical intercalation of lithium ions from a saturated LiNO3 aqueous electrolyte solution into LiV3O8 prepared by a solid-state reaction at 680 degrees C was studied with cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Results show that there are three steps of intercalation in the presence of an aqueous electrolyte, in agreement with those previously observed with organic liquid electrolytes. In addition, variations of several parameters including the charge transfer resistance (R-ct), the capacitance of the double layer (C-DL), the Warburg diffusion impedance (Z(w)), and diffusion coefficient of lithium ions (DLi+) during the intercalation process are reported. (c) 2008 Elsevier B.V. All rights reserved.