Micro-spherical FeS2/CNT powder was synthesized through one-step hydrothermal method for the first time. Carbon nanotube (CNT) had a great influence on the structure, morphology, and electrochemical performance of FeS2/CNT powder. X-ray diffraction (XRD) patterns have demonstrated that the existence of CNT can restrain the growth of marcasite during hydrothermal process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) test have shown that CNT help to form monodisperse microsphere particles. Comparing with untreated FeS2, FeS2/CNT electrode exhibits superior rate and cycling performance. The FeS2/CNT powders can sustain 491 and 370 mAh g(-1), much higher than FeS2 prepared without CNT (265 and 74 mAh g(-1)) after 50 cycles at 0.1 and 1 C (1 C = 890 mA g(-1)). Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.