Nisar Ahmad

ABSTRACT A series of Fe3O4/CNT nanocomposites are effectively synthesized by an in situ chemical co-precipitation technique. The structure, morphology and chemical composition of synthesized nanocomposites are analyzed by X-ray diffraction, Rutherford backscattering spectroscopy, scanning electron microscopy, transmission electron microscopy and fourier-transform infrared spectroscopy. The electrochemical performance of synthesized nanocomposites is tested by cyclic voltammetry (CV), charge/discharge studies and electrochemical impedance spectroscopy (EIS). The carbon nanotubes are nicely dispersed in the Fe3O4 nanoparticles for all the nanocomposites. Due to the synergistic effect arising from Fe3O4 nanoparticles and carbon nanotubes, the electrochemical properties of pure Fe3O4 material is considerably enhanced. A discharge capacity of 1093 mA h g (1) is demonstrated by Fe3O4-7% CNT nanocomposite at a current density of 100 mA g (1) with a high columbic efficiency of 98.4%. Moreover, this nanocomposite shows a stable cycling and rate performance at higher current densities. Hence, based on the above studies, such Fe3O4/CNT nanocomposite could be a possible contributor for lithium ion batteries.

ABSTRACT In this study, functionalized carbon nanotubes (CNTs) with good conductivity and high surface area are anchored with mesoporous Co3O4 nanoparticles by a facile chemical co-precipitation method. Electrochemical characterizations show that Co3O4/CNT nanocomposite delivers a capacity of 873 mAh g−1 after 50 cycles at a current density of 100 mA g−1. When the current density is increased to 250, 350 and 500 mA g−1, it still maintains a capacity of 895, 834 and 757 mAh g−1, respectively. The high capacity, rate capability and good cycling ability of Co3O4/CNT nanocomposite are attributed to the intimate interaction between the CNTs and Co3O4 nanoparticles. The CNTs not only enhance the conductivity of Co3O4 nanoparticles but also improve the structure stability of Co3O4 nanoparticles. Furthermore, the mesoporous structure of Co3O4 nanoparticles is available to the transfer of electrolyte. Our results demonstrate that CNTs reinforced Co3O4 nanocomposite could be a promising anode material for high capacity lithium-ion batteries.