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

• Published in: Advanced functional materials 2008-12, Vol.18 (24), p.3941-3946
• Main Authors: Zhang, Wei‐Ming, Wu, Xing‐Long, Hu, Jin‐Song, Guo, Yu‐Guo, Wan, Li‐Jun
• Format: Article
• Language: English
• Subjects: carbon; electrodes; iron oxides; lithium‐ion batteries; nanostructures
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200801386

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 (∼745 mA h g−1 at C/5 and ∼600 mA 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 can 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. A superior anode material for lithium‐ion batteries is realized by introducing carbon coatings on the surface of iron oxide nanospindles. The carbon coating layers not only enhance the electronic conductivity of the electrode materials, but also lead to stabilized solid electrolyte interphase films. As a result, the as‐prepared carbon‐coated Fe3O4 nanospindles exhibit very high reversible capacity, significantly improved cycling performance, and high rate performance compared with commercial magnetite particles and bare hematite nanospindles.