Enhanced electrochemical performance of Ag-coated CuCr2O4 as anode material for lithium-ion batteries

CuCr2O4/Ag is prepared by a preliminary sol-gel formation of CuCr2O4 and a subsequent chemical deposition of Ag on the surface by electroless plating. The surface morphology, structure and electrochemical behaviors of CuCr2O4/Ag and CuCr2O4 are observed and compared by various analytical techniques. It is obvious that the electrochemical property of CuCr2O4 is enhanced by Ag coating layer. The as-prepared CuCr2O4/Ag composite shows an initial discharge specific capacity of 495.6 mA h g−1, and its coulombic efficiency evolves from 27.7% to 97.8% in the initial 40 cycles. In contrast, the initial discharge specific capacity and coulombic efficiency of CuCr2O4 are 372.8 mAh g−1 and 21.7%, respectively. During the following 40 cycles, the cycling coulombic efficiency for CuCr2O4 is merely 94.3%. Besides, the reversible charge capacity of CuCr2O4/Ag is 133.9 mA h g−1 after 40 cycles. For comparison, the reversible lithium storage capacity of bare CuCr2O4 is only 100.5 mA h g−1. It suggests that the improved reversible capacity and cycling performance should be ascribed to the Ag coating layer, which improves the electronic conductivity of CuCr2O4 and may suppress the volume change of CuCr2O4 particles during repeated cycles.