ZnFe2O4@C/graphene nanocomposites as excellent anode materials for lithium batteries

ZnFe2O4 is a promising anode material for lithium ion batteries (LIBs) because of its high theoretical capacity (1000.5 mA h g(-1)), but its practical application is impeded by fast capacity fading and poor rate capability. To overcome these limitations, herein, core-shell structured ZnFe2O4@C nanoparticles were homogeneously anchored onto the surface of graphene (G) nanosheets through a mussel-inspired process and subsequent calcinations. The resulting ZnFe2O4@C/G nanocomposite delivered a reversible capacity of 705 mA h g(-1) at 0.25 C after 180 cycles (with capacity retention of 99.4%), and high rate capability of 403.5 mA h g(-1) at 5 C, thus exhibiting one of the best lithium storage properties among the reported ZnFe2O4 anodes. The excellent electrochemical performance is mainly related to the conducting, buffering and protective effects of carbon shells and graphene nanosheets on ZnFe2O4 nanoparticles. Considering its simplicity and effectiveness, this strategy might be extended to other anode materials with intrinsically low electronic conductivity, large volume-variation and severe agglomeration in the process of lithiation-delithiation.