NH4V3O8 center dot 0.2H(2)O is synthesized by sodium dodecyl sulfonate (SDS) assisted hydrothermal method and its electrochemical performance is investigated. The as-prepared material is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR) spectrum, differential scanning calorimetry and thermal gravimetry (DSC/TG), cyclic voltammetry (CV), and charge-discharge cycling test. The results show a pure NH4V3O8 center dot 0.2H(2)O phase with flake-like morphology is obtained and the average flake thickness is about 150 nm. The NH4V3O8 center dot 0.2H(2)O electrode has a good lithium ion insertion/extraction ability with the highest discharge capacity of 225.9 mAh g(-1) during 1.8-4.0V versus Li at the constant current density of 15 mA g(-1). After 30 cycles, it still maintains a high discharge capacity of 209.4 mAh g(-1), demonstrating good cyclic stability. Interestingly, at the discharge process a new (NH4)LixV3O8 center dot 0.2H(2)O compound is formed due to the new lithium ion from lithium metal anode. (C) 2010 Elsevier B.V. All rights reserved.