Fe 3O 4 dendrites reduced by carbon-coatings as high reversible capacity anodes for lithium ion batteries

Abstract

Carbon-coated magnetite dendrites (CMDs) were prepared by partial reduction of hematite dendrites (HDs) with carbon-coatings. CMDs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), and thermogravimetric analysis. The XRD results demonstrated the transformation of hematite to magnetite. As anode materials for lithium ion batteries, the CMDs showed much higher reversible capacity in the first cycle and better cycling performance compared with bare HDs. The improvement of the performance could be attributed to both the enhanced conductance and the increased structural stability coming from the carbon-coatings, which acted as elastic buffers to relieve the strains associated with the volume change during lithium insertion/extraction. Beside, the interspaces between CMDs were also propitious to relieve the strains. The results demonstrated that CMDs, with high reversible capacities and good cycling performance, were promising anode materials for lithium ion batteries.