A ferrocene-based carbon-iron lithium fluoride nanocomposite as a stable electrode material in lithium batteries.

A nanocomposite comprising carbon–iron LiF was prepared by pyrolysis of a mixture of ferrocene and LiF at 700 C under an argon atmosphere for 2 h. The structure and morphology of the material was characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET analysis, and M€ossbauer spectroscopy. The composite consists of multi-walled carbon nanotubes and onion-type graphite structures in which Fe and Fe3C nanoparticles are encapsulated, and LiF is dispersed within the carbon matrix. The sample contains both micro- (0.025 cm3 g1) and mesopores (0.14 cm3 g1), and has a total specific surface area of 82 m2 g1. Its charge/discharge performances were studied in the potential range 0.5 V to 4.3 V at a current density of 20.83 mA g1 at 25 C. It exhibited an initial discharge capacity of 324 mAh g1 with respect to the active mass of FeF3. After five cycles the capacity reached 280 mAh g1 and is maintained at about 270 mAh g1 over 200 cycles. A reversible specific capacity of about 170 mAh g1 was realized when the potential range was between 1.3 and 4.3 V.