Facial synthesis of carbon-coated ZnFe2O4/graphene and their enhanced lithium storage properties

Carbon-coated ZnFe2O4 spheres with sizes of ~110–180 nm anchored on graphene nanosheets (ZF@C/G) are successfully prepared and applied as anode materials for lithium ion batteries (LIBs). The obtained ZF@C/G presents an initial discharge capacity of 1235 mAh g−1 and maintains a reversible capacity of 775 mAh g−1 after 150 cycles at a current density of 500 mA g−1. After being tested at 2 A g−1 for 700 cycles, the capacity still retains 617 mAh g−1. The enhanced electrochemical performances can be attributed to the synergetic role of graphene and uniform carbon coating (~3–6 nm), which can inhibit the volume expansion, prevent the pulverization/aggregation upon prolonged cycling, and facilitate the electron transfer between carbon-coated ZnFe2O4 spheres. The electrochemical results suggest that the synthesized ZF@C/G nanostructures are promising electrode materials for high-performance lithium ion batteries.