Modified synthesis of [Fe/LiF/C] nanocomposite, and its application as conversion cathode material in lithium batteries

In an attempt to enhance the energy storage capacity and discharge voltage, a new cathode material based on ferrocene and LiF for lithium-ion batteries has been explored [Fe/LiF/C] nanocomposite (1) has been synthesized by pyrolysis of a ferrocene/LiF mixture at 700 °C using a rotating quartz tube setup in a furnace. The structure and morphology of the composite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Brunauer–Emmer–Teller (BET) analysis, Raman, and Mössbauer spectroscopy. The nanocomposite is composed of well-defined nanotubes which are interlinked by graphitic shell-type structures containing uniformly distribution of Fe, Fe–C, and LiF nanoparticles. The binder-free nanocomposite cathode showed enhanced electrochemical performance with the reversible specific capacity of 230 mAh g−1 (1.3–4.3 V) at 20.8 mA g−1 at room temperature. It exhibited a remarkable cyclic stability and good rate capability performances. The morphology of 1 was changed by ball milling, and the resulting nanocomposite 2 did not show any cyclic stability as a cathode. Thus, the cyclic stability and rate capability performances of 1 were attributed to its structure and morphology.

► Modified synthesis yielded a better homogeneous [Fe/LiF/C] nanocomposite.
► It consists of well-defined carbon nanotubes and graphitic core–shells encapsulated with iron nanoparticles.
► The binder-free cathode exhibits a reversible capacity of 230 mAh g−1.
► It shows good cyclic stability (>150 cycles) as well as rate capability.
► Given evidence that the morphology is crucial for the cyclic stability.