Fe3O4 nanoparticle anchored layered graphene films for high performance lithium storage

A flexible and binder-free Fe3O4/graphene film was prepared through the vacuum filtration of Fe3O4/GO suspensions, followed by an annealing process. Cross-sectional SEM images of the sandwiched films show that Fe3O4 nanoparticles homogeneously decorated onto layered graphene nanosheets and formed a nanoporous network structure. Thus, the composite film provided effective channels to promote electrolyte penetration when used as an anode for Li-ion batteries. Moreover, the good attraction between Fe3O4 and graphene is attributed to hydrogen bonding or intermolecular forces, making them beneficial for charge transfer. The unique film with excellent mechanical stability also can buffer the volume expansion during the Li-ion insertion/extraction process. After electrochemical tests, the as-prepared binder-free Fe3O4/graphene hybrid lamellar films demonstrated excellent cyclic retention with the specific capacity of 681.2 mA h g(-1) after 50 cycles, which is 3 times higher than the discharge capacity of 222.0 mA h g(-1) for pure Fe3O4, as well as good rate capability, making them promising candidates for use as anodes for Li-ion batteries.