To reduce the reaction time, electrical energy consumption, and cost, binary alpha-NiS-beta-NiS has been synthesized by a rapid, one-pot, hydrothermal autoclave microwave method within 15 min at temperatures of 160-180 degrees C. The microstructure and morphology of the alpha-NiS-beta-NiS products were characterized by means of x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). At 140 degrees C. pure hexagonal NiAs-type alpha-NiS phase was identified from the XRD patterns. With increasing reaction temperature (160-180 degrees C), the XRD evidence indicates that an increasing fraction of rhombohedral millerite-like (beta-NiS is formed as a secondary phase. The alpha-NiS-beta-NiS sample synthesized at 160 degrees C yielded good electrochemical performance in term of high reversible capacity (320 mAh g(-1) at 0.1C up to 100 cycles). Even at high rates, the sample operated at a good fraction of its capacity. The likely contributing factor to the superior electrochemical performance of the alpha-NiS-beta-NiS sample could be related to the improved morphology. TEM imaging confirmed that needle-like protrusions connect the clusters of alpha-NiS particles, and the individual protrusions indicated a very high surface area including folded sheet morphology, which helps to dissipate the surface accumulation of Li(+) ions and facilitate rapid mobility. These factors help to enhance the amount of lithium intercalated within the material. (C) 2011 Elsevier Ltd. All rights reserved.