Hollow CuFe2O4 spheres encapsulated in carbon shells as an anode material for rechargeable lithium-ion batteries

We report here a polymer-templated hydrothermal growth method and subsequent calcination to achieve carbon coated hollow CuFe2O4 spheres (H–CuFe2O4@C). This material, when used as anode for Li-ion battery, retains a high specific capacity of 550 mAh g−1 even after the 70th cycle, which is much higher than those of both CuFe2O4@C (∼300 mAh g−1) and H–CuFe2O4 (∼120 mAh g−1). And galvanostatic cycling at different current densities reveals that a capacity of 480 mAh g−1, 91% recovery of the specific capacity cycling at 100 mA g−1, can be obtained even after 50 cycles running from 100 to 1600 mA g−1. The significantly enhanced electrochemical performances of H–CuFe2O4@C with regard to Li-ion storage are ascribed to the following factors: (1) the hollow void, which could mitigate the pulverization of electrode and facilitate the lithium-ion, electron and electrolyte transport; (2) the conductive carbon coating, which could enhance the conductivity, alleviate the agglomeration problem, prevent the formation of an overly thick SEI film and buffer the electrode. Such a structural motif of H–CuFe2O4@C is promising, for electrode materials of LIBs, and points out a general strategy for creating other hollow-shell electrode materials with improved electrochemical performances.