Sandwich-structured graphene–NiFe2O4–carbon nanocomposite anodes with exceptional electrochemical performance for Li ion batteries

Graphene–NiFe2O4–carbon nanocomposites with a sandwich structure are synthesized via the hydrothermal growth of NiFe2O4 nanoparticles on graphene sheets, followed by carbon coating. As a promising anode material for Li ion batteries, the nanocomposites deliver exceptional cycle stability of 1195 mA h g−1 after 200 cycles measured at 500 mA g−1. This value is among the highest reported so far for anodes containing similar NiFe2O4 nanoparticles. The synergy arising from the conductive graphene substrate, the well-dispersed, ultrafine NiFe2O4 nanoparticles and the protective carbon layer sustaining the sandwich together is responsible for this trait.