Molybdenum-doped spinel Li[Ni(0.5+x)Mn(1.5-2x)Mox]O-4 (0 <= x <= 0.1) materials were synthesized by an ultrasonic spray pyrolysis method. Well-ordered [111] direction (octahedron shape) morphology powders were obtained at molybdenum-doped spinel. The structural, electrochemical, morphological properties, and thermal stability of the powders were characterized by X-ray diffraction, galvanostatic charge/discharge testing, scanning electron microscopy, and differential scanning calorimetry, respectively. The molybdenum doping spinel has a high discharge capacity, excellent capacity retention, rate capability, and thermal stability. (C) 2004 The Electrochemical Society.