Synthesis of carbon coated Fe3O4/SnO2 composite beads and their application as anodes for lithium ion batteries

Abstract

Two metal oxide materials, namely, Fe₃O₄ and SnO₂, were combined into one specially designed nanostructure for lithium ion battery application. Hollow and porous Fe₃O₄ beads with an average size of ～700 nm were first synthesised through a one-step solvothermal route, followed by the decoration of SnO₂ nanoparticles via a hydrothermal method. A thin carbon layer was coated to further enhance the overall electrochemical performances. Under the current density of 100 mA g^?1, the first reversible capacity of such composite beads reached 834·7 mA h g^?1. While being tested at a higher current density of 500 mA g^?1, carbon coated Fe₃O₄/SnO₂ delivered steady reversible capacities with 569·5 mA h g^?1 at two hundredth cycle. Such performances were attributed to the high theoretical capacities of the metal oxides, desired morphology in nanoscale, carbon coating layer and the synergistic effect between Fe₃O₄ and SnO₂.