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

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 similar to 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.