Synthesis of [Co/LiF/C] nanocomposite and its application as cathode in lithium-ion batteries

[Co/LiF/C] nanocomposite has been synthesized by pyrolysis of a cobaltocene/LiF mixture at 700 °C in a closed reaction vessel under argon atmosphere. The morphology, structure and composition of the material was characterized by Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen physisorption measurement (BET) and elemental analysis. The composite is comprised of hexagonally closed packed (hcp) and face centred cubic (fcc) cobalt nanoparticles and LiF, which are embedded in a matrix of graphitic nanostructures. The composite has both micro- (0.05 cm3 g−1) and mesopores (0.1 cm3 g−1), and exhibits a BET surface area of 177 m2 g−1. Electrochemical characterizations were performed versus lithium to determine the capacity, cyclic stability and to investigate the reaction mechanism. At a given current density of 27.8 mA g−1 the composite electrode exhibits an initial specific discharge capacity of 152 mAh g−1 (based on cobalt and fluorine content) which stabilizes at about 170 mAh g−1 over 70 cycles.

[Co/LiF/C] nanocomposite which is used as conversion type cathode material for lithium-ion battery. The composite comprises lithium fluoride and cobalt nanoparticles which are embedded in a matrix of carbon nanotubes and onion type shells of carbon.Figure optionsDownload as PowerPoint slideHighlights
► Lithiated state of fluoride conversion type cathode material by single step pyrolysis.
► Co and LiF nanoparticles embedded in carbon matrix.
► No carbide formation observed.
► Average specific discharge capacity of 160 mAh g−1 over 80 cycles.
► Better cyclic stability than samples prepared by ball milling.