Cu nanowire wrapped and Cu3Si anchored Si@Cu quasi core-shell composite microsized particles as anode materials for Li-ion batteries

摘要

Si@Cu quasi core-shell composite microsized particles with Cu3Si interface, prepared by ball milling and subsequent heating treatment, were investigated as anode materials for lithium ion batteries. The influence of Cu/Si mass ratio and heating treatment on its electrochemical performance was investigated by means of CV, EIS and discharge/charge test. It is found that Si&2Cu600L composite powders, which were fabricated by heat treating the Cu-Si mixed powders with mass ratio 2 at 600 degrees C for 6 h, exhibit the best electrochemical performance with 865 mAhg(-1) discharge capacity and 649 mAhg(-1) charge capacity after the 1st cycle and maintaining the charge capacity as high as 523.9 mAh/g after 100 cycles, corresponding to an initial coulombic efficiency of 75% and an average capacity fading rate of 0.23% per cycle, respectively, owing to the synergetic effect of Cu shell with good mechanical flexibility and electrical conductivity as well as Cu3Si phase both as a buffer layer accommodating the volume change of Si and as an adhesive layer increasing the electrical contact between Si and Cu upon cycling. Moreover, 10 wt% Cu nanowires, instead of carbon black, as conductive additives can further improve its rate capability significantly. (C) 2019 Elsevier B.V. All rights reserved.