Si@Cu3Si nano-composite prepared by facile method as high-performance anode for lithium-ion batteries

Abstract

Due to the high density of lithium storage and abundant mineral resources, silicon has been well accepted as a promising anode for the new-generation lithium-ion batteries. In recent years, its poor cycle stability due to drastically volumetric change has been remarkably improved by means of such composites as Si–Cu or Si–Cu3Si. However, the preparation is still complicated. The present work proposed an environmentally friendly and facile method, that is, implementing hydrogenation reduction and subsequent calcinations on the nano Si particles immersed in CuCl2 solution to obtain the Si–Cu3Si composite (denoted as Si@Cu3Si) with coherent phase boundaries. This architecture helps reduce the contact between Si and electrolyte, depressing the formation of SEI film and the cyclic deterioration of discharge capacity. It not only enhances the cyclic stability by preserving the capacity of 1000 mAhg−1 for 300 cycles, but also improves the rate capability and kinetics of the electrode. Based on detections by X-ray diffraction, scanning electron microscopy/energy dispersive spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy, the effects of morphology, composition and structure on the electrochemical performance of the nano-sized Si@Cu3Si anode was clarified in the present work.