Layered Li[Ni1/2Mn1/2]O-2 was synthesized by an ultrasonic spray pyrolysis method. The Li[Ni1/2Mn1/2]O-2 Powder was characterized by means of X-ray diffraction, charge/discharge test, and cyclic voltammetry. The discharge capacity increases linearly with increase of the upper cut-off voltage limit and attains a high discharge capacity of 187 mA h g(-1) between 2.8 and 4.6 V with excellent cyclability. A cyclic voltammetric study of the Li[Ni1/2Mn1/2]O-2 electrode showed only one redox peak implying no structural phase change during cycling.