Preparation of different FexN/rGO nanocomposites and their application as anodes for lithium-ion battery

Abstract

Iron-nitride based materials are considered to be one of the most promising anode materials for Lithium-ion batteries (LIBs) due to their good electrical conductivity and high theoretical capacity. However, iron-based nitrides are easily deteriorated in the long-term lithiation/delithiation process, which reduces the electrochemical stability and limits their large-scale application. Here, we report a Fe3N or Fe2N reduced graphene oxide nanosheets (rGO) composite prepared through a facile annealing process under different atmosphere (NH3/Ar) from Fe3O4 original material. The voids in cubic structure of Fe3N or Fe2N can be beneficial to buffer volume changes during lithiation/delithiation processes and provide active sites, and the rGO is helpful to improve electrical conductivity of composites. Moreover, the proportion of Fe3N in the composite is higher than that of Fe2N, indicating that more cubic structure can be released in Fe3N/rGO. Therefore, Fe3N/rGO showed a higher capacity (513 mA h g−1 after 200 cycles at a current density of 0.5 A g−1), better rate performance and more stable cycling performance. This work provides a new direction for the construction of iron-based nitrides with different valence states as anode active materials for LIBs using Fe3O4 as raw material.