Carbon Coated Fe3O4 Nanospindles as a Superior Anode Material for Lithium-Ion Batteries

Carbon-coated Fe3O4 nanospindles are synthesized by partial reduction of monodispersed hematite nanospindles with carbon coatings, and investigated with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and electrochemical experiments. The Fe3O4-C nanospindles show high reversible capacity (similar to 745 mA h g(-1) at C/5 and similar to 600mA h g(-1) at C/2), high coulombic efficiency in the first cycle, as well as significantly enhanced cycling performance and high rate capability compared with bare hematite spindles and commercial magnetite particles. The improvements call be attributed to the uniform and continuous carbon coating layers, which have several functions, including: i) maintaining the integrity of particles, ii) increasing the electronic conductivity of electrodes leading to the formation Of Uniform and thin solid electrolyte interphase (SEI) films on the surface, and iii) stabilizing the as-formed SEI films. The results give clear evidence of the utility of carbon coatings to improve the electrochemical performance of nanostructured transition metal oxides as Superior anode materials for lithium-ion batteries.