Nanocrystalline/amorphous Sn3O2(OH)(2); prepared by simple precipitation, was investigated as an alternative anode material for lithium secondary batteries. The material was identified by X-ray diffraction (XRD), and the microstructure of the precipitates was confirmed by high resolution transmission electron microscopy. Electrochemical tests demonstrated that the first charge and discharge capacities of Sn3O2(OH)(2) were about 1580 and 1030 mAh/g, respectively. Ex situ XRD showed a drastic structural change of electrode material to an amorphous phase during the first cycle. When the potential window was restricted between 0.0 and 0.8 V, the reversible capacity was 600 mAh/g for the first cycle and could be retained up to about 500 mAh/g even after 100 cycles. The improved cycling performance was attributed to nanocrystalline active material with the restriction of Sn aggregation by voltage cutoff. (C) 2003 The Electrochemical Society.