A novel FeS2/CNT micro-spherical cathode material with enhanced electrochemical characteristics for lithium-ion batteries

• Micro-spherical FeS2/CNT sample is prepared by one-step hydrothermal technique for the first time.
• CNT can restrain the growth of marcasite during the hydrothermal process.
• CNT can help FeS2 form dispersed micro-spherical particles and form a conductive matrix on the FeS2 particle surface.
• FeS2/CNT electrode shows superior rate capability and cycling performance compared with FeS2.

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 micro-sphere 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).