Ti/Si/Ti sandwich-like thin film as the anode of lithium-ion batteries

Abstract

Ti/Si/Ti sandwich-like thin film, which has been fabricated on copper foam by magnetron sputtering, has been studied as anode material for rechargeable lithium-ion batteries. Instrumental analyses of Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) have been employed to characterize the structure, morphology, composition and valence of the as-deposited films. Charge/discharge tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been performed to investigate the electrochemical performance of Ti/Si/Ti thin film. It is found that Ti/Si/Ti thin film delivered an initial discharge capacity of 2656 mAh g−1 and a reversible capacity of 1071 mAh g−1 after 100 cycles at 0.5C. When the discharge rate is increased to 10C, the discharge capacity is 950 mAh g−1. The enhanced electrochemical performance is mainly attributed to Ti/Si/Ti sandwich-like structure, which benefits the electrode stability and the electrode process kinetics. The results indicate that the sandwich-like structure is promising in the development of Si-based anode for rechargeable lithium-ion batteries.