Micrometer-sized LiNi0.5Mn1.5O4 single crystals were synthesized by heating a stoichiometric mixture of LiOH, MnCl2, and NiCl2 at the relatively low temperatures of 650 and 700 degrees C. X-ray diffraction (XRD) patterns and scanning electron microscopic (SEM) images showed that LiNi0.5Mn1.5O4 synthesized at 650 and 700 degrees C has cubic spinel structure with well-formed octahedral shapes. The electrochemical measurements for the Li/LiNi0.5Mn1.5O4 cell showed good charge-discharge performance with an initial discharge capacity of 130 mAh g(-1) between 4.95 and 3.00 V. The rate capability test revealed that the sample synthesized at 700 C retains 97% of its capacity in going from C/5 to the 3C rate. (c) 2006 The Electrochemical Society.