Si/Cu composite as anode material for lithium-ion batteries

Abstract

An Si/Cu composite anode was prepared using a facile solid mechanosynthesis method and wet chemical etching. Phase transition and morphologies were investigated on pristine and as-synthesized composites. Effects of presence of Al80Si20 and super p carbon on ball-milling were investigated. Moreover, the etching effect was compared with that of pristine Cu–Zn and composites by addition of NH4Cl. The results of X-ray diffraction patterns, scanning-electron-microscopy morphological images, and focus-ion-beam/energy-dispersive mapping demonstrated that the formation of the intermetallic, elemental distribution, homogeneity, and dezincification is involved with the addition of Al, super p carbon, and etching additive NH4Cl. Super p carbon avoided the formation of Cu–Si, while Al made the more homogenous distribution of Si/Cu. The two synthesized types of Si/Cu composites deliver specific capacity/retention rates of 608 mAhg−1/66.4% (Si/Cu from pure Si) and 707 mAhg−1/81.1% (Si/Cu from Al80Si20) after 200 cycles, respectively. The higher stability of the galvanostatic cycling and capability performance resulted from the homogeneity of Si and Cu.