Magnetite Nanocrystals as Anode Electrode Materials for Rechargeable Li-Ion Batteries

Monodispersed magnetite (Fe3O4) nanocrystals were synthesized and their electrochemical properties as anode electrode materials for rechargeable lithium ion batteries were measured. The magnetite anodes, in the form of monodispersed nanospheres with average diameters (< 10 nm), show particle size effects. Specifically, the first discharge curves show that the nanocrystals can hold much more Li+ per formula unit than their counterparts in bulk before the reduction begins. The electrolyte decomposition takes place before the reduction reaction is completed. The cycling performance of the Fe3O4 nanocrystals after being heated at 300 degrees C for different lengths of time show that heating can improve the integration of the nanocrystals and increase their capacity retention in consequence.