Carbon Nanohorns Carried Iron Fluoride Nanocomposite with ultrahigh rate lithium ion storage properties

Novel hierarchical carbon nanohorns (CNHs) carried iron fluoride nanocomposites have been constructed by direct growth of FeF₃·0.33H₂O nanoparticles on CNHs. In the FeF₃·0.33H₂O@CNHs nanocomposite, the mesopore CNHs play the role as conductive matrix and robust carrier to support the FeF₃·0.33H₂O nanoparticles. The intimate conductive contact between the two components can build up an express way of electron transfer for rapid Li + insertion/extraction. The CNHs can not only suppress the growth and agglomeration of FeF₃·0.33H₂O during the crystallization process, but also sever as an "elastic confinement" to support FeF₃·0.33H₂O. As was to be expected, the hierarchical FeF₃·0.33H₂O@CNHs nanocomposite exhibits impressive rate capability and excellent cycle performance. Markedly, the nanocomposite proves stable, ultrahigh rate lithium ion storage properties of 81 mAh g^-1 at charge/discharge rate of 50 C (a discharge/charge process only takes 72 s). The integration of high electron conductivity, confined nano sized FeF₃·0.33H₂O (∼5 nm), hierarchical mesopores CNHs and the "elastic confinement" support, the FeF₃·0.33H₂O@CNHs nanocomposite demonstrates excellent ultrahigh rate capability and good cycling properties.